Women receiving coronary stents faced higher procedural risk than men, but their long-term survival rates were higher, according to an analysis published online Sept. 17 in Circulation. Outcomes for both genders were better when treated with drug-eluting stents (DES) rather than bare-metal stents (BMS).
Lead author Monique Anderson, MD, of Duke University Medical Center in Durham, N.C., and colleagues conducted the data analysis of 426,996 patients aged 65 and older entered between 2004 and 2008 in the National Cardiovascular Disease Registry's Cath PCI Registry. The patients included 180,752 women. The data were linked to Medicare inpatient claims by gender and to outcomes by gender and stent type.
The authors followed patients who had received either DES or BMS, focusing on these primary endpoints: death, bleeding, vascular complications and periprocedural MI. They created a propensity-matched cohort by grouping by gender and then matching the data against numerous variables, including variables affecting stent selection, such as:
- Bleeding the preceding year;
- Contraindication to prior antithrombotics;
- Antiplatelet therapy;
- Aspirin use; and
- Known warfarin administration.
The propensity scores represented the estimated probabilities of receiving a DES vs. a BMS. To determine whether there were gender-based differences in outcomes, the researchers matched propensity scores among the male and female study population and combined the two groups.
The analysis revealed that women receiving stents were "significantly older (75.8 vs. 74.1 years) and more likely to have diabetes mellitus, CHF [congestive heart failure] and hypertension. Men were more likely to have hyperlipidemia, prior MI and CABG," they wrote.
Procedural success rates were slightly higher in women, but women had higher rates of in-hospital mortality; rates of periprocedural MI, bleeding, vascular complications, cardiogenic shock and renal failure were higher in women.
At 30 months post-procedure, women had a lower adjusted incidence of death than men. Rates of MI, bleeding or repeat revascularization did not significantly differ between genders. The incidence of death was lower for patients of both genders who were treated with DES than for patients who were treated with BMS.
The authors noted that previous studies have postulated that women's higher rates of in-hospital mortality may be due to female patients being older, sicker, smaller or less aggressively treated with pharmaceuticals. In this study, the authors adjusted for the clinical variables hypothesized as significant by other researchers, including:
- Clinical risk profile;
- Body surface area; and
- Acuity of disease.
The study authors reported that even after adjusting for these variables, the data indicated that women undergoing stenting procedures experienced higher rates of in-hospital death and complications.
"Furthermore, these findings suggest that recent advances in care since prior papers such as the establishment of sex-based guidelines for weight-based anticoagulation therapy, availability of smaller stent-based therapies and smaller vascular access devices are either under-utilized or have not eliminated the sex-mortality gap."