Sudden cardiac death accounts for 1/3 of cardiovascular deaths following ACS

A pooled cohort analysis found that sudden cardiac death accounted for nearly one-third of cardiovascular deaths among patients who were discharged from the hospital for a non-ST-segment elevation acute coronary syndrome.

In addition, patients with recurrent MI or rehospitalization had a significantly increased risk for sudden cardiac death.

Lead researcher Paul L. Hess, MD, MHS, of the Veterans Affairs Eastern Colorado and Health Care System in Denver, and colleagues published their results online in JAMA Cardiology on March 16.

The researchers analyzed data on 37,555 patients with high-risk unstable angina or acute MI from four multicenter, randomized, placebo-controlled studies: the Apixaban for Prevention of Acute Ischemic Events 2 (APPRAISE-2), Study of Platelet Inhibition and Patient Outcomes (PLATO), Thrombin Receptor Antagonist for Clinical Event Reduction in Acute Coronary Syndrome (TRACER) and Targeted Platelet Inhibition to Clarify the Optimal Strategy to Medically Manage Acute Coronary Syndromes (TRILOGY ACS).

Of the participants, 67.4 percent were men and 85.5 percent were white. The median age was 65 years old. Patients who received an implantable cardioverter defibrillator after randomization were excluded. The researchers conducted their analyses from Jan. 2, 2014 to Dec. 11, 2015.

After a median follow-up of 12.1 months, there were 2,109 deaths. Of the 1,640 cardiovascular deaths, 31.3 percent were sudden cardiac deaths. The rate of sudden cardiac death was 1.18 per 100 patient-years of follow-up, while the cumulative incidences of sudden cardiac death were 0.79 percent at six months, 1.65 percent at 18 months and 2.37 percent at 30 months.

The researchers added that the following factors at baseline were significantly associated with sudden cardiac death: Reduced left ventricular ejection fraction, older age, diabetes mellitus, lower estimated glomerular filtration rate, higher heart rate, prior myocardial infarction, peripheral artery disease, Asian race, male sex and high Killip class.

They mentioned the study had a few limitations, including that they only used variables that were included in databases from the trials. They also noted that patients in studies were more selected than real-world patients, so the results may not be generalizable to a broad population. Further, the observational design meant that unmeasured or residual confounding might have existed. In addition, the studies used experimental therapies that are not all currently the standard of care, and the cardiac or electrical origin of sudden cardiac death could not be confirmed in all instances.