Higher mortality rates in women after PCI driven by noncardiac causes

The higher rates of all-cause mortality after percutaneous coronary intervention (PCI) observed in women can be attributed to noncardiac factors, suggests a single-center study published in Circulation: Cardiovascular Interventions.

A team of researchers from Mayo Clinic in Rochester, Minnesota, analyzed cause-specific mortality among 16,280 men and 6,847 women who received PCI at their institution between 1991 and 2012. They noted previous studies have typically used all-cause mortality as an endpoint rather than cause-specific mortality, which is problematic considering noncardiac death is currently more common among PCI recipients than cardiac causes.

Forty-seven percent of the females and 39 percent of the males died within five years of follow-up. When broken down into seven-year increments, women PCI recipients in the most recent era were 26 percent less likely to die of cardiac causes than those in the earliest timeframe. Men experienced a 17 percent relative decrease in cardiac deaths over time.

Overall, 33.8 percent of women and 38 percent of men died of cardiac causes. Women were older on average at the time of PCI and had a greater burden of noncardiac and cardiac comorbidities, including hypertension and diabetes.

“The current study demonstrated a major temporal shift in cause of death after PCI in both women and men such that in the current era of PCI, both women and men are twice as likely to die from noncardiac compared with cardiac disease,” wrote lead author Claire E. Raphael, MD, and colleagues. “The decrease in cardiac mortality observed after PCI for the 3 eras is consistent with the temporal decline in cardiac deaths observed in women and men in the post-PCI and general population and may, in part, be related to the increase in use of secondary prevention medications observed in both sexes across eras.”

Raphael et al. said their findings suggest future clinical trials should be tweaked to more accurately reflect the risks associated with a treatment or a procedure. Different variables may warrant consideration in statistical adjustment models given the cardiac versus noncardiac likelihood of death in a given population.

“Variables collected and used in statistical models have tended to be cardiac centric and procedural in type,” they wrote. “Given that the dominant cause of death in the contemporary post-PCI population is noncardiac, these factors have diminishing or no influence on long-term all-cause mortality after PCI compared with parameters of noncardiac risk.”

The researchers found chronic disease and heart failure were the most common causes of death among women who received PCI, with five-year mortality rates of 5.4 and 3.9 percent, respectively. Cancer (5.4 percent) and myocardial infarction/sudden death (4.3 percent) were the commonest causes of death among men in the study.

“Although these findings likely result from differences in baseline risk in women and men, they do suggest sex-specific differences in long-term healthcare needs after PCI,” Raphael and colleagues wrote.