What Explains the Higher Risk of Death in Women Who Have Received Treatment with PCI following STEMI?

Although previous studies have shown that women are less likely to receive acute reperfusion treatment for ST elevation myocardial infarction (STEMI) in clinical practice, there is comparatively little data on "gender differences in adjunctive treatment and outcome in the setting of primary PCI." Given this lack of data, what is the impact of female gender on hospital outcome of primary percutaneous coronary intervention (PCI) in patients with STEMI in clinical practice?

A study presented during the "Women, STEMI, and PCI Trials" Abstract Oral Session Tuesday morning at the American Heart Association Scientific Sessions 2009 sought to answer that question. Krishnaraj Rathod, from The London Chest Hospital, London, UK presented "Females Have a Higher Rate of Mortality after Primary PCI," a retrospective study that analyzed the factors that may contribute to gender differences in mortality rates in patients in the UK following PCI for STEMI.

Researchers collected clinical, procedural, and follow-up data on 1,163 patients (880 males, 283 females) who underwent primary PCI at a London-based tertiary referral center between January 2004 and December 2007. The researchers reported that "clinical information was prospectively collected onto a database at the time of the procedure and outcome assessed by all-cause mortality provided by the [UK] Office of National Statistics."

Female patients in the registry were on average eight years older than male patients (average age of 67 years in women vs. average age of 59 years in men). The researchers found similar incidences of diabetes in women and men (19% compared to 15%) and prior MI (11% vs. 13%). They also found no significant difference in rates of hypertension, hypercholesterolemia, and other clinical variables. Similarly, they reported no differences in procedural characteristics, including adjunctive medical treatment (including GPIIb/IIIa).

Patients in this cohort experienced similar mortality at discharge (1% vs. 0.8%). Analysis of the data did reveal a significantly higher mortality rate in females beginning 60 days post-discharge, a difference that persists up to five years post-MI (13.5% vs 7.5%), even after adjusting for age.

The researchers concluded that women who undergo primary PCI face significantly mortality compared to men who undergo the same procedure, "despite similar risk factor profiles and degree of coronary artery disease. This difference is still significant when correcting for age."