Week 15 – CHADS2

“Validation of Clinical Classification Schemes for Predicting Stroke”

JAMA. 2001 June 13;285(22):2864-70. [free full text]

Atrial fibrillation is the most common cardiac arrhythmia and affects 1-2% of the overall population with increasing prevalence as people age. Atrial fibrillation also carries substantial morbidity and mortality due to the risk of stroke and thromboembolism although the risk of embolic phenomenon varies widely across various subpopulations. In 2001, the only oral anticoagulation options available were warfarin and aspirin, which had relative risk reductions of 62% and 22%, respectively, consistent across these subpopulations. Clinicians felt that high risk patients should be anticoagulated, but the two common classification schemes, AFI and SPAF, were flawed. Patients were often classified as low risk in one scheme and high risk in the other. The schemes were derived retrospectively and were clinically ambiguous. Therefore, in 2001, a group of investigators combined the two existing schemes to create the CHADS2 scheme and applied it to a new data set.

Population (NRAF cohort): Hospitalized Medicare patients ages 65-95 with non-valvular AF not prescribed warfarin at hospital discharge.

Intervention: Determination of CHADS2 score (1 point for recent CHF, hypertension, age ≥ 75, and DM; 2 points for a history of stroke or TIA)

Comparison: AFI and SPAF risk schemes

Measured Outcome: Hospitalization rates for ischemic stroke (per ICD-9 codes from Medicare claims), stratified by CHADS2 / AFI / SPAF scores.

Calculated Outcome: performance of the various schemes, based on c statistic (a measure of predictive accuracy in a binary logistic regression model)

1733 patients were identified in the NRAF cohort. When compared to the AFI and SPAF trials, these patients tended be older (81 in NRAF vs. 69 in AFI vs. 69 in SPAF), have a higher burden of CHF (56% vs. 22% vs. 21%), are more likely to be female (58% vs. 34% vs. 28%), and have a history of DM (23% vs. 15% vs. 15%) or prior stroke/TIA (25% vs. 17% vs. 8%). The stroke rate was lowest in the group with a CHADS2 = 0 (1.9 per 100 patient years, adjusting for the assumption that aspirin was not taken). The stroke rate increased by a factor of approximately 1.5 for each 1-point increase in the CHADS2 score.

CHADS2 score           NRAF Adjusted Stroke Rate per 100 Patient-Years
0                                      1.9
1                                      2.8
2                                      4.0
3                                      5.9
4                                      8.5
5                                      12.5
6                                      18.2

The CHADS2 scheme had a c statistic of 0.82 compared to 0.68 for the AFI scheme and 0.74 for the SPAF scheme.

The CHADS2 scheme provides clinicians with a scoring system to help guide decision making for anticoagulation in patients with non-valvular AF.

The authors note that the application of the CHADS2 score could be useful in several clinical scenarios. First, it easily identifies patients at low risk of stroke (CHADS2 = 0) for whom anticoagulation with warfarin would probably not provide significant benefit. The authors argue that these patients should merely be offered aspirin. Second, the CHADS2 score could facilitate medication selection based on a patient-specific risk of stroke. Third, the CHADS2 score could help clinicians make decisions regarding anticoagulation in the perioperative setting by evaluating the risk of stroke against the hemorrhagic risk of the procedure. Although the CHADS2 is no longer the preferred risk-stratification scheme, the same concepts are still applicable to the more commonly used CHA2DS2-VASc.

This study had several strengths. First, the cohort was from seven states that represented all geographic regions of the United States. Second, CHADS2 was pre-specified based on previous studies and validated using the NRAF data set. Third, the NRAF data set was obtained from actual patient chart review as opposed to purely from an administrative database. Finally, the NRAF patients were older and sicker than those of the AFI and SPAF cohorts, and thus the CHADS2 appears to be generalizable to the very large demographic of frail, elderly Medicare patients.

As CHADS2 became widely used clinically in the early 2000s, its application to other cohorts generated a large intermediate-risk group (CHADS2 = 1), which was sometimes > 60% of the cohort (though in the NRAF cohort, CHADS2 = 1 accounted for 27% of the cohort). In clinical practice, this intermediate-risk group was to be offered either warfarin or aspirin. Clearly, a clinical-risk predictor that does not provide clear guidance in over 50% of patients needs to be improved. As a result, the CHA2DS2-VASc scoring system was developed from the Birmingham 2009 scheme. When compared head-to-head in registry data, CHA2DS2-VASc more effectively discriminated stroke risk among patients with a baseline CHADS2 score of 0 to 1. Because of this, CHA2DS2-VASc is the recommended risk stratification scheme in the AHA/ACC/HRS 2014 Practice Guideline for Atrial Fibrillation. In modern practice, anticoagulation is unnecessary when CHA2DS2-VASc score = 0, should be considered (vs. antiplatelet or no treatment) when score = 1, and is recommended when score ≥ 2.

Further Reading:
1. AHA/ACC/HRS 2014 Practice Guideline for Atrial Fibrillation
2. CHA2DS2-VASc (2010)
3. 2 Minute Medicine

Summary by Ryan Commins, MD

Image Credit: Alisa Machalek, NIGMS/NIH – National Insititue of General Medical Sciences, Public Domain

Week 11 – AFFIRM

“A Comparison of Rate Control and Rhythm Control in Patients with Atrial Fibrillation”

by the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) Investigators

N Engl J Med. 2002 Dec 5;347(23):1825-33. [free full text]

It seems like the majority of patients with atrial fibrillation that we encounter today in the inpatient setting are being treated with a rate-control strategy, as opposed to a rhythm-control strategy. There was a time when both approaches were considered acceptable, and perhaps rhythm control was even the preferred initial strategy. The AFFIRM trial was the landmark study to address this debate.

The trial randomized patients with atrial fibrillation (judged “likely to be recurrent”) aged 65 or older “or who had other risk factors for stroke or death” to either 1) a rhythm-control strategy with one or more drugs from a pre-specified list and/or cardioversion to achieve sinus rhythm or 2) a rate-control strategy with beta-blockers, CCBs, and/or digoxin to a target resting HR ≤ 80 and a six-minute walk test HR ≤ 110. The primary endpoint was death during follow-up. The major secondary endpoint was a composite of death, disabling stroke, disabling anoxic encephalopathy, major bleeding, and cardiac arrest.

4060 patients were randomized. Death occurred in 26.7% of rhythm-control patients versus 25.9% of rate-control patients (HR 1.15, 95% CI 0.99 – 1.34, p = 0.08). The composite secondary endpoint occurred in 32.0% of rhythm control-patients versus 32.7% of rate-control patients (p = 0.33). Rhythm-control strategy was associated with a higher risk of death among patients older than 65 and patients with CAD (see Figure 2). Additionally, rhythm-control patients were more likely to be hospitalized during follow-up (80.1% vs. 73.0%, p < 0.001) and to develop torsades de pointes (0.8% vs. 0.2%, p = 0.007).

This trial demonstrated that a rhythm-control strategy in atrial fibrillation offers no mortality benefit over a rate-control strategy. At the time of publication, the authors wrote that rate control was an “accepted, though often secondary alternative” to rhythm control. Their study clearly demonstrated that there was no significant mortality benefit to either strategy and that hospitalizations were greater in the rhythm-control group. In subgroup analysis that rhythm control led to higher mortality among the elderly and those with CAD. Notably, 37.5% of rhythm-control patients had crossed over to rate control strategy by 5 years of follow-up, whereas only 14.9% of rate-control patients had switched over to rhythm control.

But what does this study mean for our practice today? Generally speaking, rate control is preferred in most patients, particularly the elderly and patients with CHF, whereas rhythm control may be pursued in patients with persistent symptoms despite rate control, patients unable to achieve rate control on AV nodal agents alone, and patients younger than 65. Both the AHA/ACC (2014) and the European Society of Cardiology (2016) guidelines have extensive recommendations that detail specific patient scenarios.

Further Reading / References:
1. Cardiologytrials.org
2. Wiki Journal Club
3. 2 Minute Medicine
4. Visual abstract @ Visualmed

Summary by Duncan F. Moore, MD

Image Credit: Drj via Wikimedia Commons

Week 6 – SOLVD

“Effect of Enalapril on Survival in Patients with Reduced Left Ventricular Ejection Fractions and Congestive Heart Failure”

by the Studies of Left Ventricular Dysfunction (SOLVD) Investigators

N Engl J Med. 1991 Aug 1;325(5):293-302. [free full text]

Heart failure with reduced ejection fraction (HFrEF) is a very common and highly morbid condition. We now know that blockade of the renin-angiotensin-aldosterone system (RAAS) with an ACEi or ARB is a cornerstone of modern HFrEF treatment. The 1991 SOLVD trial played an integral part in demonstrating the benefit of and broadening the indication for RAAS blockade in HFrEF.

The trial enrolled patients with HFrEF and LVEF ≤ 35% who were already on treatment (but not on an ACEi) and had Cr ≤ 2.0 and randomized them to treatment with enalapril BID (starting at 2.5mg and uptitrated as tolerated to 20mg BID) or treatment with placebo BID (again, starting at 2.5mg and uptitrated as tolerated to 20mg BID). Of note, there was a single-blind run-in period with enalapril in all patients, followed by a single-blind placebo run-in period. Finally, the patient was randomized to his/her actual study drug in a double-blind fashion. The primary outcomes were all-cause mortality and death from or hospitalization for CHF. Secondary outcomes included hospitalization for CHF, all-cause hospitalization, cardiovascular mortality, and CHF-related mortality.

2569 patients were randomized. Follow-up duration ranged from 22 to 55 months. 510 (39.7%) placebo patients died during follow-up compared to 452 (35.2%) enalapril patients (relative risk reduction of 16% per log-rank test, 95% CI 5-26%, p = 0.0036). See Figure 1 for the relevant Kaplan-Meier curves. 736 (57.3%) placebo patients died or were hospitalized for CHF during follow-up compared to 613 (47.7%) enalapril patients (relative risk reduction 26%, 95% CI 18-34, p < 0.0001). Hospitalizations for heart failure, all-cause hospitalizations, cardiovascular deaths, and deaths due to heart failure were all significantly reduced in the enalapril group. 320 placebo patients discontinued the study drug versus only 182 patients in the enalapril group. Enalapril patients were significantly more likely to report dizziness, fainting, and cough. There was no difference in the prevalence of angioedema.

Treatment of HFrEF with enalapril significantly reduced mortality and hospitalizations for heart failure. The authors note that for every 1000 study patients treated with enalapril, approximately 50 premature deaths and 350 heart failure hospitalizations were averted. The mortality benefit of enalapril appears to be immediate and increases for approximately 24 months. Per the authors, “reductions in deaths and rates of hospitalization from worsening heart failure may be related to improvements in ejection fraction and exercise capacity, to a decrease in signs and symptoms of congestion, and also to the known mechanism of action of the agent – i.e., a decrease in preload and afterload when the conversion of angiotensin I to angiotensin II is blocked.” Strengths of this study include its double-blind, randomized design, large sample size, and long follow-up. The fact that the run-in period allowed for the exclusion prior to randomization of patients who did not immediately tolerate enalapril is a major limitation of this study.

Prior to SOLVD, studies of ACEi in HFrEF had focused on patients with severe symptoms. The 1987 CONSENSUS trial was limited to patients with NYHA class IV symptoms. SOLVD broadened the indication of ACEi treatment to a wider group of symptoms and correlating EFs. Per the current 2013 ACCF/AHA guidelines for the management of heart failure, ACEi/ARB therapy is a Class I recommendation in all patients with HFrEF in order to reduce morbidity and mortality.

Further Reading/References:
1. Wiki Journal Club
2. 2 Minute Medicine
3. Effects of enalapril on mortality in severe congestive heart failure – Results of the Cooperative North Scandinavian Enalapril Survival Study (CONSENSUS). 1987.
4. 2013 ACCF/AHA guideline for the management of heart failure: executive summary

Summary by Duncan F. Moore, MD

Week 1 – CAST

“Mortality and Morbidity in Patients Receiving Encainide, Flecainide, or Placebo”

The Cardiac Arrhythmia Suppression Trial (CAST)

N Engl J Med. 1991 Mar 21;324(12):781-8. [free full text]

Ventricular arrhythmias are common following MI, and studies have demonstrated that PVCs and other arrhythmias such as non-sustained ventricular tachycardia (NSVT) are independent risk factors for cardiac mortality following MI. As such, by the late 1980s, many patients with PVCs post-MI were treated with antiarrhythmic drugs in an attempt to reduce mortality. The 1991 CAST trial sought to prove what predecessor trials had failed to prove – that suppression of such rhythms post-MI would improve survival.

This trial took post-MI patients with PVCs (with no sustained VT) and reduced EF and randomized them to an open-label titration period in which encainide, flecainide, or moricizine was titrated to suppress at least 80% of the PVCs and 90% of the runs of NSVT. Patients were then either randomized to continuation of the antiarrhythmic drug assigned during the titration period or transitioned to a placebo. The primary outcome was death or cardiac arrest with resuscitation, “either of which was due to arrhythmia.”

The trial was terminated early due to increased mortality in the encainide and flecainide treatment groups. 1498 patients were randomized following successful titration during the open-label period, and they were reported in this paper. The results of the moricizine arm were reported later in a different paper (CAST-II). The RR of death or cardiac arrest due to arrhythmia was 2.64 (95% CI 1.60–4.36; number needed to harm = 28.2). See Figure 1 on page 783 for a striking Kaplan-Meier curve. The RR of death or cardiac arrest due to all causes was 2.38 (95% CI 1.59–3.57; NNH = 20.6). Regarding other secondary outcomes, cardiac death/arrest due to any cardiac cause was similarly elevated in the treatment group, and there were no significant differences in non-lethal endpoints among the treatment and placebo arms.

In this large RCT, the treatment of asymptomatic ventricular arrhythmias with encainide and flecainide in patients with LV dysfunction following MI resulted in increased mortality. This study provides a classic example of how a treatment that seems to make intuitive sense based on observational data can be easily and definitively disproven with a placebo-controlled trial with hard endpoints (e.g. death). Although PVCs and NSVT are associated with cardiac death post-MI and reducing these arrhythmias might seem like an intuitive strategy for reducing death, correlation does not equal causation. Modern expert opinion at UpToDate notes no role for suppression of asymptomatic PVCs or NSVT in the peri-infarct period. Indeed such suppression may increase mortality. As noted on Wiki Journal Club, modern ACC/AHA guidelines “do not comment on the use of antiarrhythmic medications in ACS care.”

Further Reading/References:
1. Wiki Journal Club
2. 2 Minute Medicine
3. CAST-I Trial @ ClinicalTrials.gov
4. CAST-II trial publication, NEJM 1992
5. UpToDate “Clinical features and treatment of ventricular arrhythmias during acute myocardial infarction”

Summary by Duncan F. Moore, MD

Image Credit: By CardioNetworks: Drj – CardioNetworks: Nsvt.png, CC BY-SA 3.0

Week 48 – HAS-BLED

“A Novel User-Friendly Score (HAS-BLED) To Assess 1-Year Risk of Major Bleeding in Patients with Atrial Fibrillation”

Chest. 2010 Nov;138(5):1093-100. [free full text]

Atrial fibrillation (AF) is a well-known risk factor for ischemic stroke. Stroke risk is further increased by individual comorbidities such as CHF, HTN, and DM and can be stratified with scores such as CHADS2 and CHA2DS2VASC. The recommendation for patients with intermediate stroke risk is treatment with oral anticoagulation (OAC). However, stroke risk is often closely related to bleeding risk, and the benefits of anticoagulation for stroke need to be weighed against the added risk of bleeding. At the time of this study, there were no validated and user-friendly bleeding risk-stratification schemes. This study aimed to develop a practical risk score to estimate the 1-year risk of major bleeding (as defined in the study) in a contemporary, real-world cohort of patients with AF.

Population: adults with EKG or Holter-proven diagnosis of AF
Exclusion criteria: mitral valve stenosis, valvular surgery

(Patients were identified from the prospectively developed database of the multi-center Euro Heart Survey on AF. Among 5,272 patients with AF, 3,456 were free of mitral valve stenosis or valve surgery and completed their 1-year follow-up assessment.)

No experiment was performed in this retrospective cohort study.

In a derivation cohort, the authors retrospectively performed univariate analyses to identify a range of clinical features associated with major bleeding (p < 0.10). Based on systematic reviews, they added additional risk factors for major bleeding. Ultimately, the result was a list of comprehensive risk factors that make up the acronym HAS-BLED:

H – Hypertension (> 160 mmHg systolic)
A – Abnormal renal (HD, transplant, Cr > 2.26 mg/dL) and liver function (cirrhosis, bilirubin >2x normal w/ AST/ALT/ALP > 3x normal) – 1 pt each for abnormal renal or liver function
S – Stroke

B – Bleeding (prior major bleed or predisposition to bleed)
L – Labile INRs (time in therapeutic range < 60%)
E – Elderly (age > 65)
D – Drugs (i.e. ASA, clopidogrel, NSAIDs) or alcohol use (> 8 units per week) concomitantly – 1 pt each for use of either

Each risk factor represents one point each. The HAS-BLED score was then compared to the HEMORR2HAGES scheme, a previously developed tool for estimating bleeding risk.


  • incidence of major bleeding within 1 year
  • bleeds per 100 patient-years, stratified by HAS-BLED score
  • c-statistic for the HAS-BLED score in predicting the risk of bleeding


  • major bleeding: bleeding causing hospitalization, Hgb drop >2 g/L, or bleeding requiring blood transfusion (excluded hemorrhagic stroke)
  • hemorrhagic stroke: focal neurologic deficit of sudden onset that is diagnosed by a neurologist, lasting > 24h, and caused by bleeding

3,456 AF patients (without mitral valve stenosis or valve surgery) who completed their 1-year follow-up were analyzed retrospectively. 64.8% (2242) of these patients were on OAC (with 12.8% (286) of this subset on concurrent antiplatelet therapy), 24% (828) were on antiplatelet therapy alone, and 10.2% (352) received no antithrombotic therapy. 1.5% (53) of patients experienced a major bleed during the first year. 17% (9) of these patients sustained intracerebral hemorrhage.

HAS-BLED Score       Bleeds per 100-patient years
0                                        1.13
1                                         1.02
2                                        1.88
3                                        3.74
4                                        8.70
5                                        12.50
6*                                     0.0                   *(n = 2 patients at risk, neither bled)

Patients were given a HAS-BLED score and a HEMORR2HAGES score. C-statistics were then used to determine the predictive accuracy of each model overall as well as within patient subgroups (OAC alone, OAC + antiplatelet, antiplatelet alone, and no antithrombotic therapy).

C statistics for HAS-BLED:
For overall cohort, 0.72 (95% CI 0.65-0.79); for OAC alone, 0.69 (95% CI 0.59-0.80); for OAC + antiplatelet, 0.78 (95% CI 0.65-0.91); for antiplatelet alone, 0.91 (95% CI 0.83-1.00); and for those on no antithrombotic therapy, 0.85 (95% CI 0.00-1.00).

C statistics for HEMORR2HAGES:
For overall cohort, 0.66 (95% CI 0.57-0.74); for OAC alone, 0.64 (95% CI 0.53-0.75); for OAC + antiplatelet, 0.83 (95% CI 0.74-0.91); for antiplatelet alone, 0.83 (95% CI 0.68-0.98); and for those on no antithrombotic therapy, 0.81 (95% CI 0.00-1.00).

This study helped to establish a practical and user-friendly assessment of bleeding risk in AF. HAS-BLED is superior to its predecessor HEMORR2HAGES because the acronym is easier to remember, the assessment is quicker and simpler to perform, and all risk factors are readily available from the clinical history or routine testing. Both stratification tools had (grossly) similar c-statistics for the overall cohort – 0.72 for HAS-BLED versus 0.66 for HEMORR2HAGES. However, HAS-BLED was particularly useful when looking at antiplatelet therapy alone or no antithrombotic therapy at all (0.91 and 0.85, respectively).

This study is useful because it provides evidence-based, easily calculable, and actionable risk stratification in the assessment of bleeding risk in AF. In prior studies, such as ACTIVE-A (ASA + clopidogrel versus ASA alone for patients with AF deemed unsuitable for OAC), almost half of all patients (n= ~3500) were given a classification of “unsuitable for OAC,” which was based solely on physicians’ clinical judgement without a predefined objective scoring. Now, physicians have an objective way to assess bleed risk rather than “gut feeling” or wanting to avoid iatrogenic insult.

The RE-LY trial used the HAS-BLED score to decide which patients with AF should get the standard dabigatran dose (150mg BID) rather than a lower dose (110mg BID) for anticoagulation. This risk-stratified dosing resulted in a significant reduction in major bleeding compared with warfarin but maintained a similar reduction in stroke risk.

Furthermore, the HAS-BLED score could allow the physician to be more confident when deciding which patients may be appropriate for referral for a left atrial appendage occlusion device (e.g. Watchman).

The study had a limited number of major bleeds and a short follow-up period, and thus it is possible that other important risk factors for bleeding were not identified. Also, there were large numbers of patients lost to 1-year follow-up. These patients likely had more comorbidities and may have transferred to nursing homes or even died. Their loss to follow-up and thus exclusion from this retrospective study may have led to an underestimate of true bleeding rates. Furthermore, generalizability is limited by the modest number of very elderly patients (i.e. 75-84 and ≥85), who likely represent the greatest bleeding risk. Finally, this study did not specify what proportion of its patients were on warfarin for their OAC, but given that dabigatran, rivaroxaban, and apixaban were not yet approved for use in Europe (2008, 2008, and 2011, respectively) for the majority of the study, we can assume most patients were on warfarin. Thus the generalizability of HAS-BLED risk stratification to the DOACs is limited.

Bottom Line:
HAS-BLED provides an easy, practical tool to assess the individual bleeding risk of patients with AF. Oral anticoagulation should be considered for scores of 3 or less. If HAS-BLED scores are ≥4, it is reasonable to think about alternatives to oral anticoagulation.

Further Reading/References:
1. 2 Minute Medicine
2. ACTIVE-A trial
3. RE-LY trial
4. RE-LY @ Wiki Journal Club
5. HAS-BLED Calculator
6. HEMORR2HAGES Calculator
7. Watchman (for Healthcare Professionals)

Summary by Patrick Miller, MD

Week 45 – Look AHEAD

“Cardiovascular Effects of Intensive Lifestyle Intervention in Type 2 Diabetes”

by the Look AHEAD (Action for Health in Diabetes) Research Group

N Engl J Med. 2013 Jul 11;369(2):145-54. [free full text]

NIH treatment guidelines recommend weight loss in patients with T2DM and overweight or obesity. Such weight loss is associated with improvements in glycemic control, hypertension, and quality of life. While retrospective cohort studies and a prospective trial of bariatric surgery in T2DM suggested that weight loss was associated with reduction in rates of cardiovascular events and mortality, no prospective trial has demonstrated such benefits from non-surgical weight loss. The Look AHEAD study was designed to determine if aggressive lifestyle intervention for weight loss in T2DM could provide benefits in hard cardiovascular outcomes.

Population: patients with T2DM, age 45-75, and BMI 25+ (27+ if on insulin), A1c < 11%, SBP < 160 mmHg, DBP < 100 mmHg, and the ability to complete a maximal exercise test

Intervention: an “intensive lifestyle intervention” with goal weight loss ≥ 7.0%, implemented via weekly group and individual counseling (decreasing in frequency over course of study). Specific recommended interventions: caloric restriction to 1200-1800 kcal/day, use of meal-replacement products, ≥ 175 min/wk of moderate-intensity exercise

Comparison: “diabetes support and education” comprised of three group meetings per year focused on diet, exercise, and social support (yearly meetings starting year 5)
Primary – composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, and hospitalization for angina.

Of note, hospitalization for angina was not a pre-specified component of the primary outcome. It was added 2 years into the trial after event rates of the other cardiovascular components were lower than expected.


  • composite of death from cardiovascular causes, nonfatal MI, nonfatal stroke (the original primary outcome)
  • composite of death (all-cause), nonfatal MI, nonfatal stroke, hospitalization for angina
  • composite of death (all-cause), nonfatal MI, stroke, hospitalization for angina, CABG, PCI, hospitalization for heart failure, or peripheral vascular disease

2570 patients were randomized to the intensive lifestyle intervention (ILI) group, and 2575 were randomized to the diabetes support and education (DSE) group. Baseline characteristics were similar in both groups. Mean BMI was 36.0, and 14% of patients had a history of cardiovascular disease.

At one year, mean weight loss from baseline was 8.6% in the ILI group and 0.7% in the DSE group (p < 0.001); however, weight loss at the end of the study was 6.0% in the ILI group and 3.5% in the DSE group (p < 0.001). The average group difference in A1c was 0.22% lower in the ILI group (p < 0.001) although A1c values were slightly higher than baseline in both groups at the end of the study (see Figure 1D for the time course).

The trial was terminated prematurely after interim analysis revealed that the likelihood of a significant positive primary result was approximately 1%. Median follow up was 9.6 years at the time of termination.

There was no group difference in rates of the primary composite cardiovascular endpoint. The endpoint occurred in 403 patients in the ILI group and 418 patients in the DSE group (1.83 and 1.92 events per 100 person-years, respectively; HR 0.95, 95% CI 0.83-1.09, p = 0.51).

There were no group differences in rates of the secondary composite outcomes.

Among patients with T2DM and overweight or obesity, an intensive lifestyle intervention for weight loss was not associated with improved cardiovascular outcomes, when compared to a control group-based diabetes support and education intervention.

Overall, this trial was a notable failure. Despite the trial’s adequate power and its authors shifting the goalposts at 2 years into the study, the intervention did not demonstrate “hard” cardiovascular benefits. Furthermore, generalizability of this study is limited by its exclusion of patients who could not complete a maximal-fitness test at baseline. With respect to diet, this trial did not address diet composition, only caloric restriction and increased physical activity.

The authors suggest that “a sustained weight loss of more than that achieved in the intervention group may be required to reduce the risk of cardiovascular disease,” and thus the trial failed to return a positive result.

Weight loss in patients with T2DM and overweight or obesity remains a Class A recommendation by the American Diabetes Association. The ADA also notes that weight loss may be achieved at 2 years with a “Mediterranean” diet. The 2013 PREDIMED study demonstrated that such a diet reduces the risk of ASCVD in high-risk patients.

Further Reading/References:
1. Look AHEAD @ Wiki Journal Club
2. American Diabetes Association. “Executive Summary: Standards of Medical Care in Diabetes – 2013.”
3. PREDIMED @ Wiki Journal Club

Summary by Duncan F. Moore, MD

Week 41 – PROVE IT-TIMI 22

“Intensive versus Moderate Lipid Lowering with Statins after Acute Coronary Syndromes”

by the Pravastatin or Atorvastatin Evaluation and Infection Therapy–Thrombolysis in Myocardial Infarction 22 Investigators

N Engl J Med. 2004 Apr 8;350(15):1495-504. [free full text]

Statins are a cornerstone of therapy for the primary and secondary prevention of atherosclerotic cardiovascular disease. In the early 2000s, atorvastatin (Lipitor) was an immensely popular and profitable drug for its maker Pfizer. Notably, the 2001 MIRACL trial demonstrated that early use of high-intensity atorvastatin after UA/NSTEMI significantly reduced the risk of adverse cardiovascular outcomes at 16 weeks. In this context, Bristol-Meyers Squibb designed a non-inferiority trial to compare a relatively low dose of its new drug pravastatin (Pravachol) to high-intensity atorvastatin 80mg for the prevention of adverse cardiovascular outcomes following ACS.

Population: adults with ACS in the preceding 10 days, post-PCI (if planned/applicable), with total cholesterol < 240 (< 200 if already on lipid-lowering therapy)

Intervention: pravastatin 40mg PO daily

Note – the dose of pravastatin could be increased to 80mg daily in a blinded fashion if LDL remained > 125 mg/dL on two consecutive follow-up visits.

Comparison: atorvastatin 80mg PO daily (“intensive therapy”)

Primary – composite of all-cause mortality, MI, UA requiring rehospitalization, revascularization > 30 days after randomization, and stroke

The authors pre-specified an upper limit of non-inferiority as a 17% increase in the hazard ratio for the primary outcome within the pravastatin group at 2 years.


  • composite of death from CAD, non-fatal MI, or revascularization
  • composite of death from CAD or non-fatal MI
  • the individual components of the composite primary outcome

Subgroup analyses of primary outcome: sex, baseline LDL > 125, UA, MI, DM

4162 patients were randomized. Baseline characteristics were similar among the two groups, aside from a higher rate of peripheral arterial disease among the pravastatin group. Regarding the type of ACS, approximately 1/3 of cases were UA, 1/3 were NSTEMIs, and 1/3 were STEMIs. 69% of patients received PCI prior to randomization. Approximately 25% of patients were taking statins at the time of inclusion. At inclusion, the median LDL level was 106 mg/dL.

During follow-up, the median LDL level among pravastatin patients was 95 mg/dL and 62 mg/dL in the intensive therapy (atorvastatin) patients. Ultimately, 8% of pravastatin patients had their dose uptitrated to 80mg daily due to LDL levels remaining above 125 mg/dL.

At two-year follow-up, the primary composite outcome was noted in 26.3% of patients in the standard-dose pravastatin group but only 22.4% of the intensive-therapy atorvastatin group (ARR = 3.9%, p = 0.005, NNT = 25.6). Pravastatin therapy failed to meet its prespecified non-inferiority criteria; in fact, atorvastatin was decidedly superior.

The composite of death due to CAD, non-fatal MI, or revascularization was reduced by 25% in the atorvastatin group (p < 0.001). The composite of death due to CAD or non-fatal MI was not different among the two groups. Regarding individual components of the primary outcome: there was a 14% reduction in the need for revascularization and a 29% reduction in recurrent UA in the atorvastatin group (p = 0.04 and 0.02, respectively). There were no group differences in all-cause mortality, MI, or stroke. Discontinuation rates were 21.4% in the pravastatin group and 22.8% in the atorvastatin group (p = 0.11).

Among patients with recent ACS, high-intensity atorvastatin was superior to standard-dose pravastatin in preventing a composite of cardiovascular outcomes.

Bristol-Meyers Squibb had counted on this trial to show the non-inferiority of its new drug pravastatin to high-intensity atorvastatin in the secondary prevention of ASCVD. Instead, this trial established the dominance of high-intensity statin therapy for secondary prevention.

The treatment groups in this trial differed both by drug and by relative dosage intensity of the assigned drug. Whether the improvements in outcomes were from one or both of these factors is unknown. The marked group difference in LDL reduction correlates with these interventions and outcomes, but this paper does not establish a causal relationship between LDL reduction and improved cardiovascular outcomes.

The current standard of care is to initiate high-intensity statin therapy as early as possible after the diagnosis of ACS. Per UpToDate, atorvastatin 80mg is the best-studied high-intensity statin regimen and an excellent default. However, rosuvastatin 20mg or 40mg is an acceptable alternative. Their expert opinion also recommends adding ezetimibe 10mg daily in patients with LDL > 70 mg/dL despite high-intensity statin therapy.

Further Reading/References:
1. Wiki Journal Club
2. 2 Minute Medicine
3. UpToDate “Low density lipoprotein-cholesterol (LDL-C) lowering after an acute coronary syndrome”

Summary by Duncan F. Moore, MD

Week 38 – POISE

“Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery: a randomised controlled trial”

aka the PeriOperative Ischemic Evaluation (POISE) trial

Lancet. 2008 May 31;371(9627):1839-47. [free full text]

Non-cardiac surgery is commonly associated with major cardiovascular complications. It has been hypothesized that perioperative beta blockade would reduce such events by attenuating the effects of the intraoperative increases in catecholamine levels. Prior to the 2008 POISE trial, small- and moderate-sized trials had revealed inconsistent results, alternately demonstrating benefit and non-benefit with perioperative beta blockade. The POISE trial was a large RCT designed to assess the benefit of extended-release metoprolol succinate (vs. placebo) in reducing major cardiovascular events in patients of elevated cardiovascular risk.

Population: patients age 45+ undergoing non-cardiac surgery with estimated LOS 24+ hrs and elevated risk of cardiac disease à either 1) hx of CAD, 2) peripheral vascular disease, 3) hospitalization for CHF within past 3 years, 4) undergoing major vascular surgery, 5) or any three of the following seven risk criteria: undergoing intrathoracic or intraperitoneal surgery, hx CHF, hx TIA, hx DM, Cr > 2.0, age 70+, or undergoing urgent/emergent surgery.

Notable exclusion criteria: HR < 50, 2nd or 3rd degree heart block, asthma, already on beta blocker, prior intolerance of beta blocker, hx CABG within 5 years and no cardiac ischemia since

Intervention: metoprolol succinate (extended-release) 100mg PO starting 2-4 hrs before surgery, additional 100mg at 6-12 hrs postoperatively, followed by 200mg daily for 30 days.

Patients unable to take PO meds postoperatively were given metoprolol infusion.

Comparison: placebo PO / IV at same frequency as metoprolol arm

Primary – composite of cardiovascular death, non-fatal MI, and non-fatal cardiac arrest at 30 days

Secondary (at 30 days)

  • cardiovascular death
  • non-fatal MI
  • non-fatal cardiac arrest
  • all-cause mortality
  • non-cardiovascular death
  • MI
  • cardiac revascularization
  • stroke
  • non-fatal stroke
  • CHF
  • new, clinically significant atrial fibrillation
  • clinically significant hypotension
  • clinically significant bradycardia

Pre-specified subgroup analyses of primary outcome:

9298 patients were randomized. However, fraudulent activity was detected at participating sites in Iran and Colombia, and thus 947 patients from these sites were excluded from the final analyses. Ultimately, 4174 were randomized to the metoprolol group, and 4177 were randomized to the placebo group. There were no significant differences in baseline characteristics, pre-operative cardiac medications, surgery type, or anesthesia type between the two groups (see Table 1).

Regarding the primary outcome, metoprolol patients were less likely than placebo patients to experience the primary composite endpoint of cardiovascular death, non-fatal MI, and non-fatal cardiac arrest (HR 0.84, 95% CI 0.70-0.99, p = 0.0399). See Figure 2A for the relevant Kaplan-Meier curve. Note that the curves separate distinctly within the first several days.

Regarding selected secondary outcomes (see Table 3 for full list), metoprolol patients were more likely to die from any cause (HR 1.33, 95% CI 1.03-1.74, p = 0.0317). See Figure 2D for the Kaplan-Meier curve for all-cause mortality. Note that the curves start to separate around day 10. Cause of death was analyzed, and the only group difference in attributable cause was an increased number of deaths due to sepsis or infection in the metoprolol group (data not shown). Metoprolol patients were more likely to sustain a stroke (HR 2.17, 95% CI 1.26-3.74, p = 0.0053) or a non-fatal stroke (HR 1.94, 95% CI 1.01-3.69, p = 0.0450). Of all patients who sustained a non-fatal stroke, only 15-20% made a full recovery. Metoprolol patients were less likely to sustain new-onset atrial fibrillation (HR 0.76, 95% CI 0.58-0.99, p = 0.0435) and less likely to sustain a non-fatal MI (HR 0.70, 95% CI 0.57-0.86, p = 0.0008). There were no group differences in risk of cardiovascular death or non-fatal cardiac arrest. Metoprolol patients were more likely to sustain clinically significant hypotension (HR 1.55, 95% CI 1.38-1.74, P < 0.0001) and clinically significant bradycardia (HR 2.74, 95% CI 2.19-3.43, p < 0.0001).

Subgroup analysis did not reveal any significant interaction with the primary outcome by RCRI, sex, type of surgery, or anesthesia type.

In patients with cardiovascular risk factors undergoing non-cardiac surgery, the perioperative initiation of beta blockade decreased the composite risk of cardiovascular death, non-fatal MI, and non-fatal cardiac arrest and increased the overall mortality risk and risk of stroke.

This study affirms its central hypothesis – that blunting the catecholamine surge of surgery is beneficial from a cardiac standpoint. (Most patients in this study had an RCRI of 1 or 2.) However, the attendant increase in all-cause mortality is dramatic. The increased mortality is thought to result from delayed recognition of sepsis due to masking of tachycardia. Beta blockade may also limit the physiologic hemodynamic response necessary to successfully fight a serious infection. In retrospective analyses mentioned in the discussion, the investigators state that they cannot fully explain the increased risk of stroke in the metoprolol group. However, hypotension attributable to beta blockade explains about half of the increased number of strokes.

Overall, the authors conclude that “patients are unlikely to accept the risks associated with perioperative extended-release metoprolol.”

A major limitation of this study is the fact that 10% of enrolled patients were discarded in analysis due to fraudulent activity at selected investigation sites. In terms of generalizability, it is important to remember that POISE excluded patients who were already on beta blockers.

Currently, per expert opinion at UpToDate, it is not recommended to initiate beta blockers preoperatively in order improve perioperative outcomes. POISE is an important piece of evidence underpinning the 2014 ACC/AHA Guideline on Perioperative Cardiovascular Evaluation and Management of Patients Undergoing Noncardiac Surgery, which includes the following recommendations regarding beta blockers:

  • Beta blocker therapy should not be started on the day of surgery (Class III – Harm, Level B)
  • Continue beta blockers in patients who are on beta blockers chronically (Class I, Level B)
  • In patients with intermediate- or high-risk preoperative tests, it may be reasonable to begin beta blockers
  • In patients with ≥ 3 RCRI risk factors, it may be reasonable to begin beta blockers before surgery
  • Initiating beta blockers in the perioperative setting as an approach to reduce perioperative risk is of uncertain benefit in those with a long-term indication but no other RCRI risk factors
  • It may be reasonable to begin perioperative beta blockers long enough in advance to assess safety and tolerability, preferably > 1 day before surgery

Further Reading/References:
1. Wiki Journal Club
2. 2 Minute Medicine
3. UpToDate, “Management of cardiac risk for noncardiac surgery”
4. 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines.

Summary by Duncan F. Moore, MD


“Angiotensin-Neprilysin Inhibition versus Enalapril in Heart Failure”

by the Prospective Comparison of ARNI with ACEI to Determine Impact on Global Mortality and Morbidity in Heart Failure Trial (PARADIGM-HF) investigators

N Engl J Med. 2014 Sep 11;371(11):993-1004. [free full text]

Thanks to the CONSENSUS and SOLVD trials, angiotensin-converting enzyme (ACE) inhibitors have been a cornerstone of the treatment of heart failure with reduced ejection fraction (HFrEF) for years.

Neprilysin is a neutral endopeptidase that degrades several peptides, including natriuretic peptides, bradykinin, and adrenomedullin. Inhibiting neprilysin increases levels of these substances and thus counteracts the neurohormonal overactivation of heart failure (which would otherwise lead to vasoconstriction, sodium retention, and maladaptive remodeling). Prior experimental data has demonstrated that, in terms of cardiovascular outcomes, neprilysin inhibition with an ARB is superior to ARB monotherapy. However, a clinical trial of concurrent neprilysin-inhibitor and ACE inhibitor therapy resulted in unacceptably high rates of serious angioedema. This study sought to show improved cardiac and mortality outcomes with neprilysin inhibition plus an ARB when compared to enalapril alone.

Inclusion Criteria: ≥18 y/o; NYHA class II, III, or IV; LVEF ≤ 35%; BNP ≥ 150 or NT-proBNP ≥600

Exclusion Criteria: Symptomatic hypotension, SBP < 100mmHg at screening or 95mmHg at randomization, eGFR < 30, or decrease in eGFR by 25% between screening and randomization, K+ > 5.2, or history of angioedema/side effects to ACE inhibition or ARBs

Intervention: sacubitril/valsartan 200mg BID

Comparison: enalapril 10mg BID

Trial design notes: Screened patients were initially given sacubitril/valsartan, followed by enalapril in single blinded run-in phases, in order to ensure similar tolerance of the drugs prior to randomization. Subsequently, patients who tolerated both drugs were randomized in a double-blind manner to treatment with one of the drugs. 

Primary – composite of death from cardiovascular causes or first hospitalization for heart failure


4187 patients were randomized to the sacubitril/valsartan group, and 4212 were randomized to the enalapril group.

The primary endpoint (composite death due to cardiovascular causes or first hospitalization for HF) occurred in 914 patients (21.8%) in the sacubitril/valsartan group and 1117 patients (26.5%) in the enalapril group (p < 0.001; NNT = 21). Death due to cardiovascular causes occurred 558 times in the sacubitril/valsartan group and 693 times in the enalapril group (13.3% vs. 16.5%, p < 0.001; NNT = 31). Hospitalization for heart failure occurred (at least once) 537 times in the sacubitril/valsartan group and 658 times in the enalapril group (12.8% vs. 15.6%, p <0.001; NNT = 36).

Regarding secondary outcomes, the mean change in KCCQ score was a reduction of 2.99 points (i.e. a worsening of symptoms) in the sacubitril/valsartan group, versus a reduction of 4.63 points in the enalapril group (p = 0.001). There was no significant group difference in time to new-onset atrial fibrillation or time to diminished renal function.

Regarding safety outcomes, patients in the sacubitril/valsartan group were more likely to have symptomatic hypotension compared to patients in the enalapril group (14.0% vs. 9.2%; p <0.001; NNH = 21). However, patients in the enalapril group were more likely to have cough, serum creatinine ≥2.5, or potassium ≥6.0 compared to sacubitril/valsartan (p value varies, all significant). There was no group difference in rates of angioedema (p = 0.13).

In patients with HFrEF, inhibition of both angiotensin II and neprilysin with sacubitril/valsartan significantly reduced the risk of cardiovascular death or hospitalization for heart failure when compared to treatment with enalapril alone.

This study had several strengths. The treatment with sacubitril/valsartan was compared to treatment with a dose of enalapril that had previously been shown to reduce mortality when compared with placebo. Furthermore, the study used a run-in phase to ensure that patients could tolerate an enalapril dose that had previously been shown to reduce mortality. Finally, more patients in the enalapril group than in the sacubitril/valsartan group stopped the study drug due to adverse effects (12.3% vs. 10.7%, p=0.03).

This study ushered in a new era in heart failure management and added a new medication class – Angiotensin Receptor-Neprilysin Inhibitors or ARNIs – to the arsenal of available heart failure drugs. Entresto (sacubitril/valsartan), the ARNI posterchild, has been advertised widely over the past several years. However, clinical use so far has been lower than expected. Novartis, Entresto’s drug maker, is currently sponsoring PARAGON-HF, a trial of Entresto in patients with heart failure with preserved ejection fraction (HFpEF).

The 2017 ACC/AHA update to the guidelines for management of symptomatic HFrEF states that primary inhibition of the renin-angiotensin system with an ARNI in conjunction with evidence-based beta blockade and aldosterone antagonism is a Class I recommendation (Level B evidence). However, it does not favor this regimen over the Level-A-evidence regimens of an ARB or ACE inhibitor substituted for the ARNI. Yet the new guidelines also state that patients who have chronic symptomatic HFrEF of NYHA class II or III and tolerate an ACE inhibitor or ARB should substitute an ARNI for the ACE inhibitor or ARB in order to further reduce morbidity and mortality (Class I recommendation, level B evidence). See pages 15 and 17 here to read the details.

Bottom line: Among patients with symptomatic HFrEF, treatment with an ARNI reduces cardiovascular mortality and HF hospitalizations when compared to treatment with enalapril. Due to this study’s impact, the use of ARNIs is now a Class I recommendation by the 2017 ACC/AHA guidelines for the treatment of HFrEF. Despite its higher cost, the use of sacubitril/valsartan appears to be cost-effective in terms of QALYs gained.

Further Reading/References:
1. Wiki Journal Club
2. 2 Minute Medicine
3. ACC/AHA 2017 Focused Update for Guideline Management of Heart Failure
4. CardioBrief, “After Slow Start Entresto Is Poised For Takeoff.”
5. PARAGON-HF @ ClinicalTrials.gov
6. McMurray et al., “Cost-effectiveness of sacubitril/valsartan in the treatment of heart failure with reduced ejection fraction.” Heart, 2017.

Summary by Patrick Miller, MD

Week 34 – PLATO

“Ticagrelor versus Clopidogrel in Patients with Acute Coronary Syndromes”

by The Study of Platelet Inhibition and Patient Outcomes (PLATO) investigators

N Engl J Med. 2009 Sep 10;361(11):1045-57. [free full text]

In patients with acute coronary syndrome (ACS), with or without ST-segment elevation, clinical practice guidelines recommend dual antiplatelet therapy with aspirin plus one of either clopidogrel, prasugrel, or ticagrelor to reduce risk of thrombosis. The 2009 PLATO trial was designed to determine whether ticagrelor was superior to clopidogrel for the prevention of vascular events and death in patients presenting with ACS as well as whether this potential benefit came with an increased risk of major bleeding events.

Patients hospitalized for ACS with or without ST-elevations with symptom onset during the previous 24 hours.

If there were no ST-elevations, patients were required to have at least 2 of 3 of the following: ST change reflecting ischemia, elevated cardiac biomarkers (i.e. troponin), or one of several risk factors (age ≥ 60, prior MI/CABG, CAD w/ ≥ 50% stenosis in ≥ 2 vessels, prior ischemic stroke/TIA/carotid stenosis ≥ 50%, DM, PAD, CrCl < 60)

Intervention: ticagrelor 180mg loading dose followed by 90mg BID + aspirin

Comparison: clopidogrel 300mg loading dose followed by 75mg daily + aspirin

Primary: composite of death from vascular causes, MI, or CVA


  • major bleeding (fatal bleeding, intracranial bleeding, intrapericardial bleeding w/ tamponade, hemorrhagic shock, decline of Hgb < 5.0, or requiring transfusion of 4 units pRBC)
  • all-cause mortality, MI, or stroke
  • composite of death from vascular mortality, MI, stroke, recurrent severe ischemia, recurrent ischemia, TIA, or other arterial thrombotic event
  • stent thrombosis


18,624 patients from 862 centers in 43 countries were recruited and enrolled in the study. 9,333 were randomized to the ticagrelor group, and 9291 were randomized to the clopidogrel group. Patients were followed for up to 12 months.

The two treatment groups did not statistically differ in baseline characteristics, non-study medications following randomization, or procedures following randomization. Both groups started the study drug at a median of 11.3 hours after the onset of chest pain.

The primary end point (death from vascular causes, MI, or CVA) occurred less often in the ticagrelor group than in the clopidogrel group – 9.8% vs 11.7% (HR 0.77 – 0.92; p < 0.001; NNT = 52.6).

The groups did not significantly differ in terms of major bleeding – 11.6% vs. 11.2% (HR 1.04; 95% CI 0.95 – 1.13; p = 0.43).

Patients who received ticagrelor trended toward an increased rate of intracranial bleeding (26 [0.3%] vs. 14 [0.2%], p = 0.06), including a statistically significant increase in fatal intracranial bleeding (11 [0.1%] vs. 1 [0.01%], p = 0.02) as well as non-CABG bleeding (4.5% vs. 3.8%, p = 0.03). However, there were fewer episodes of other types of fatal bleeding in the ticagrelor group.

Regarding other secondary outcomes, ticagrelor performed better in:

  • composite of all-cause, MI, or stroke – 10.2% vs. 12.3% (HR 0.84; 95% CI 0.77 – 0.92; p < 0.001; NNT 47.6)
  • composite of death from vascular causes, MI, stroke, severe recurrent ischemia, recurrent ischemia, TIA, or other arterial thrombotic event – 14.6% vs. 16.7% (HR 0.88; 95% CI 0.81 – 0.95; p < 0.001; NNT 47.6)
  • stent thrombosis – 1.3% vs. 1.9% (HR 0.67; 95% CI 0.50-0.91; p = 0.009, NNT = 167).

Dyspnea was more common in the ticagrelor group than in the clopidogrel group (13.8% vs 7.8%, p < 0.001). There was a higher incidence of ventricular pauses in the first week in the ticagrelor group relative to the clopidogrel group; however, the two groups did not differ in incidence of syncope or pacemaker implantation. Discontinuation of study drug due to adverse event was more common in the ticagrelor group (7.4% vs. 6.0%). Ticagrelor was also associated with elevations in uric acid and creatinine.

PLATO demonstrated that treatment of ACS with ticagrelor (vs. clopidogrel) significantly reduced the rate of death from vascular causes, MI, or stroke, without increasing the risk of major bleeding.

 Although ticagrelor patients did demonstrate higher rates of intracranial and non-CABG bleeding, this bleeding did not qualify as “major bleeding.” They also complained more frequently of dyspnea (a known adverse effect of the drug). Discontinuation of ticagrelor due to dyspnea occurred in 0.9% of patients. Due to this risk of dyspnea, as well as the risk of elevated serum uric acid and creatinine, caution should be used in those with a history of COPD, asthma, CHF, gout, and CKD who are considering using ticagrelor.

Strengths of this study include that it was a double-blind, randomized controlled trial with a large patient population. Weaknesses include that the study was funded by AstraZeneca, manufacturers of Brilinta (the brand name of ticagrelor). Also, the study drug did not perform as well in North American sites or underweight patients, yet the authors do not offer clear explanations as to why.

Bottom line:
Patients with a high risk of thrombosis and a low risk of bleeding may benefit most from ticagrelor. Ticagrelor has a mortality benefit when compared to clopidogrel. But ticagrelor should be used with caution in those with pulmonary disease (e.g. COPD or asthma), CKD, and heart block (due to association with ventricular pauses).

Drug cost: At time of study. Ticagrelor: $108/month; Clopidogrel: $26/month

Further Reading/References
1. Wiki Journal Club
2. 2 Minute Medicine
3. UpToDate, “Long-term antiplatelet therapy after coronary artery stenting in stable patients”
4. 2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients with Coronary Artery Disease

Summary by Patrick Miller, MD