Gender-specific findings in interventional cardiology: negative for PCI, positive for CRT?

Abstract

At present, gender-specific disparities still persist in cardiovascular health and care, and specifically in the delivery and outcomes of coronary revascularisation therapy. Of the 1.3 million percutaneous coronary intervention (PCI) procedures performed in 2006 in the USA, only 35% were performed in women. This is rather surprising since the benefits of PCI, particularly in high-risk women with acute coronary syndromes (ACS) and ST-segment elevation myocardial infarction (STEMI), are well known. Moreover, for those women treated with PCI, unadjusted mortality and (vascular and bleeding) complication rates remain significantly higher than in men. In patients undergoing contemporary PCI, using both bare-metal and drug-eluting stents (with sirolimus and paclitaxel), the benefits of reduction in restenosis and repeat target lesion and target vessel revascularisation are independent of gender. However, the hopeful thought that stents would eliminate the difference in mortality in women and men following the stent procedure has not been realised. For patients treated with stents, the gender difference in in-hospital and 30-day mortality has persisted in the setting of both acute myocardial infarction and elective/urgent procedures. Whether these gender differences are explained by pathophysiology, by impaired access to guideline-recommended therapies, by biology or bias, by lack of a robust evidence base in women, or by the artificial comparison between women and men as their control group remains a matter of controversy [1]. Do the ‘negative’ PCI data also hold for cardiac resynchronisation therapy (CRT) in women? A recent study by Mooyaart et al. [2] evaluated in 577 patients (431 men, 147 women) whether a gender difference existed in the long-term outcomes after CRT and whether gender is an independent predictor of mortality, beyond other clinical and echocardiographic characteristics. During a mean follow-up of 34 ± 25 months, 197 patients died (158 men and 39 women). Kaplan-Meier analysis showed a significant difference in long-term survival between the women and men (p = 0.007). The 2-year all-cause mortality rate was 15% in men and 8% in women (p = 0.025). It was clearly revealed that female gender was an independent predictor of long-term survival, together with heart failure aetiology and renal function. In particular, women with heart failure due to a non-ischaemic aetiology showed the best long-term survival rate. The authors concluded that female gender and non-ischaemic aetiology were independently associated with better long-term survival after CRT. These encouraging findings have been confirmed by Arshad et al. [3] who investigated the factors related to gender-specific outcomes for death and heart failure events in the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy) trial in 1820 patients (453 female, 1367 male). Overall, female patients had a better result from CRT-D therapy than male patients, with a significant 69% reduction in death or heart failure (p < 0.001) and 70% reduction in heart failure alone (p < 0.001). In addition, women showed a significant 72% reduction in all-cause mortality in the total population. These beneficial CRT-D effects among women were associated with consistently greater echocardiographic evidence of reverse cardiac remodelling in women than in men. To summarise, the ‘negative’ PCI findings in women suggest that the ongoing gender disparities in access to and delivery of evidence-based guideline-recommended revascularisation therapies for patients with ACS and STEMI represent potential opportunities to improve care and outcomes, particularly in women. On the other hand, for CRT in women, recent findings offer a more ‘positive’ perspective than in men. Although gender-specific designed prospective studies are required to draw any definite conclusions on the observed survival benefit in women after CRT, the two above-mentioned studies form at least a good basis to treat many women suffering from heart failure with CRT.