Reduction in overall occurrences of ischemic events with vorapaxar: results from TRACER

Disparities in Advanced Peripheral Arterial Disease Presentation by Socioeconomic Status

Background

Diabetes and peripheral arterial disease (PAD) often synergistically lead to foot ulceration, infection, and gangrene, which may require lower limb amputation. Worldwide there are disparities in the rates of advanced presentation of PAD for vulnerable populations. This study examined rates of advanced presentations of PAD for unemployed patients, those residing in low Index of Economic Resources (IER) areas, and those in rural areas of Australia.

Methods

A retrospective study was conducted at a regional tertiary care centre (2008–2018). To capture advanced presentations of PAD, the proportion of operative patients presenting with complications (gangrene/ulcers), the proportion of surgeries that are amputations, and the rate of emergency to elective surgeries were examined. Multivariable logistic regression adjusting for year, age, sex, Charlson Comorbidity Index, and sociodemographic variables was performed.

Results

In the period examined, 1115 patients underwent a surgical procedure for PAD. Forty-nine per cent of patients had diabetes. Following multivariable testing, the rates of those requiring amputations were higher for unemployed (OR 1.99(1.05–3.79), p = 0.036) and rural patients (OR 1.83(1.21–2.76), p = 0.004). The rate of presentation with complications was higher for unemployed (OR 7.2(2.13–24.3), p = 0.001), disadvantaged IER (OR 1.91(1.2–3.04), p = 0.007), and rural patients (OR 1.73(1.13–2.65), p = 0.012). The rate of emergency to elective surgery was higher for unemployed (OR 2.32(1.18–4.54), p = 0.015) and rural patients (OR 1.92(1.29–2.86), p = 0.001).

Conclusions

This study found disparities in metrics capturing delayed presentations of PAD: higher rates of presentations with complications, higher amputation rates, and increased rates of emergency to elective surgery, for patients of low socioeconomic status and those residing in rural areas. This suggests barriers to appropriate, effective, and timely care exists for these patients.

Effects of initial invasive vs. initial conservative treatment strategies on recurrent and total cardiovascular events in the ISCHEMIA trial

AIMS

The International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial prespecified an analysis to determine whether accounting for recurrent cardiovascular events in addition to first events modified understanding of the treatment effects.

METHODS AND RESULTS

Patients with stable coronary artery disease (CAD) and moderate or severe ischaemia on stress testing were randomized to either initial invasive (INV) or initial conservative (CON) management. The primary outcome was a composite of cardiovascular death, myocardial infarction (MI), and hospitalization for unstable angina, heart failure, or cardiac arrest. The Ghosh-Lin method was used to estimate mean cumulative incidence of total events with death as a competing risk. The 5179 ISCHEMIA patients experienced 670 index events (318 INV, 352 CON) and 203 recurrent events (102 INV, 101 CON). A single primary event was observed in 9.8% of INV and 10.8% of CON patients while ≥2 primary events were observed in 2.5% and 2.8%, respectively. Patients with recurrent events were older; had more frequent hypertension, diabetes, prior MI, or cerebrovascular disease; and had more multivessel CAD. The average number of primary endpoint events per 100 patients over 4 years was 18.2 in INV [95% confidence interval (CI) 15.8-20.9] and 19.7 in CON (95% CI 17.5-22.2), difference -1.5 (95% CI -5.0 to 2.0, P = 0.398). Comparable results were obtained when all-cause death was substituted for cardiovascular death and when stroke was added as an event.

CONCLUSIONS

In stable CAD patients with moderate or severe myocardial ischaemia enrolled in ISCHEMIA, an initial INV treatment strategy did not prevent either net recurrent events or net total events more effectively than an initial CON strategy.

CLINICAL TRIAL REGISTRATION

ISCHEMIA ClinicalTrials.gov number, NCT01471522, https://clinicaltrials.gov/ct2/show/NCT01471522.

Alirocumab Reduces Total Hospitalizations and Increases Days Alive and Out of Hospital in the ODYSSEY OUTCOMES Trial

BACKGROUND

In ODYSSEY OUTCOMES (Evaluation of Cardiovascular Outcomes After an Acute Coronary Syndrome During Treatment With Alirocumab), alirocumab was compared with placebo, added to high-intensity or maximum tolerated statin treatment after acute coronary syndrome in 18 924 patients. Alirocumab reduced first occurrence of the primary composite end point-coronary heart disease death, nonfatal myocardial infarction, fatal or nonfatal ischemic stroke, or hospitalization for unstable angina-as well as total nonfatal cardiovascular events and all-cause deaths. The present analysis determined whether alirocumab reduced total (first and subsequent) hospitalizations and death and increased days alive and out of hospital (DAOH) and percent DAOH in ODYSSEY OUTCOMES.

METHODS AND RESULTS

In prespecified analyses, hazard functions for total hospitalizations and death were jointly estimated by a semiparametric model, while in post hoc analyses, DAOH and percent DAOH were compared between treatment groups with Poisson regression and one-inflated beta regression, respectively. With 16 629 total hospitalizations and 726 deaths, 331 fewer hospitalizations, and 58 fewer deaths were observed with alirocumab compared with placebo, translating to 15.6 total hospitalizations or deaths avoided with alirocumab per 1000 patient-years of assigned treatment. Alirocumab reduced total hospitalizations (hazard ratio, 0.96 [95% CI, 0.92-1.00]; P=0.04) and increased DAOH relative to placebo (rate ratio, 1.003 [95% CI, 1.000-1.007]; P=0.05), primarily through a reduction in days dead (rate ratio, 0.847 [95% CI, 0.728-0.986]; P=0.03). Patients randomized to alirocumab were also more likely to survive to the end of the study without hospitalization (odds ratio, 1.06 [95% CI, 1.00-1.13]; P=0.03).

CONCLUSIONS

Alirocumab reduced total hospitalizations with corresponding small increases in DAOH and percent DAOH. These outcomes provide alternative patient-centered metrics to capture the totality of alirocumab clinical efficacy after acute coronary syndrome.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01663402.

Differential occurrence, profile, and impact of first recurrent cardiovascular events after an acute coronary syndrome

OBJECTIVE

Acute coronary syndrome (ACS) trials typically use a composite primary outcome (myocardial infarction [MI], stroke, or cardiovascular death), but differential patient characteristics, timing, and consequences associated with individual component end points as first events have not been well studied. We compared patient characteristics and prognostic significance associated with first cardiovascular events in the post-ACS setting for initially stabilized patients.

METHODS

We combined patient-level data from 4 trials of post-ACS antithrombotic therapies (PLATO, APPRAISE-2, TRACER, and TRILOGY ACS) to characterize the timing of and characteristics associated with first cardiovascular events (MI, stroke, or cardiovascular death). Landmark analysis at 7 days after index ACS presentation was used to focus on spontaneous, postdischarge events that were not confounded by in-hospital procedural complications. Using a competing risk framework, we tested for differential associations between prespecified covariates and the occurrence of nonfatal stroke vs MI as the first event, and we examined subsequent events after the first nonfatal event.

RESULTS

Among 46,694 patients with a median follow-up of 358 (25th, 75th percentiles 262, 486) days, a first ischemic event occurred in 4,307 patients (9.2%) as follows: MI in 5.8% (n = 2,690), stroke in 1.0% (n = 477), and cardiovascular death in 2.4% (n = 1,140). Older age, prior stroke/transient ischemic attack, prior atrial fibrillation, and higher diastolic blood pressure were associated with a significantly greater risk of stroke vs MI, whereas prior percutaneous coronary intervention was associated with a greater risk of MI vs stroke. Second events occurred in 32% of those with a first nonfatal stroke at a median of 13 (3, 59) days after the first event and in 32% of those with a first nonfatal MI at a median of 35 (5, 137) days after the first event. The most common second event was a recurrent MI among those with MI as the first event and cardiovascular death among those with stroke as the first event.

CONCLUSIONS

Approximately 9% of patients experienced a first cardiovascular event in the post-ACS setting during a median follow-up of 1 year. Although the profile and prognostic implications of stroke vs MI as the first nonfatal event differ substantially, approximately one-third of these patients experienced a second event, typically soon after the first event. These findings have implications for improving post-ACS care and influencing the design of future cardiovascular trials.

Vorapaxar: A novel agent to be considered in the secondary prevention of myocardial infarction

Patients receiving therapy for the secondary prevention of myocardial infarction (MI) are still at high risk of a major cardiovascular event or death despite the use of currently available treatment strategy. Vorapaxar, an oral protease-activated receptor antagonist, is a novel antiplatelet drug that has been recently approved to provide further risk reduction. The results of two Phase III trials (thrombin receptor antagonists for clinical event reduction and the TRA 2°P-TIMI 50) have showed that vorapaxar, in addition to standard of care therapy, has the potential to provide further risk reduction in patients with prior MI. A search was made on PubMed on articles related to clinical trials and clinical consideration with the use of vorapaxar. This review article summarizes the results of Phase II trials, Phase III trials, subgroup analysis, precautions, and drug interaction with the use of vorapaxar.

Platelet thrombin receptor antagonism with vorapaxar: pharmacology and clinical trial development

Oral antiplatelet therapies for secondary prevention of ischemic recurrences in patients with atherosclerotic disease manifestations include aspirin and P2Y12 receptor antagonists. Despite the use of these therapies, patients remain at risk for recurrent ischemic events, which may be attributed to other platelet signaling pathways which continue to be activated. More intense antithrombotic strategies have been investigated, including identifying additional targets to modulate platelet activation. Among these, thrombin-mediated platelet activation through PAR-1 has been subject to broad clinical investigation. Vorapaxar is the only PAR-1 receptor antagonists that completed large-scale clinical investigations and is approved for clinical use. This manuscript provides an overview of the pharmacology and clinical trial development of vorapaxar as well as its role in clinical practice.