Women have a higher risk of in-hospital death than men following coronary artery bypass grafting (CABG) although long-term survival is similar between the sexes, according to 20-year UK research.

The propensity-matched study also suggests that greater use of off-pump CABG (OPCABG) may help to reduce the excess hospital mortality risk in women.

The findings underscore the need for a “female-tailored” perioperative approach for women undergoing CABG, the researchers reported in Openheart [link here].

“Females undergoing CABG surgery have worse preoperative risk profile, experience some intraoperative inequalities including less LIMA and overall number of grafts, suffer higher in-hospital mortality and longer hospital stay than males,” the authors noted. 

“The use of OPCABG surgery may mitigate the risk of in-hospital mortality in females.”

The pre-matched study population included 14,136 patients, of whom 81.9% were men and 18.1% women.

Use of CABG surgery was 55% in both groups, with no difference in cardiopulmonary bypass (CPB) time, but women received fewer left internal mammary artery (LIMA) grafts (84% vs 91%, p<0.001) and fewer total grafts (median 2 vs 3m p<0.001).

Following surgery, women had: 

• Higher in-hospital mortality (2.2% vs 1.4%, p=0.002);
• Longer hospital stays (median 7 vs 6 days, p<0.001); and
• Higher stroke rates (1.1% vs 0.7%, OR 1.55, p=0.046). 

Over the study period, women in the pre-matched population also had poorer survival than men, the authors noted.

The propensity-matched cohort consisted of 2,573 men and 2,573 women.

The female group were less likely to receive a LIMA graft (84% vs 88%) or a right internal mammary artery (RIMA) graft (2.1% vs 4.1%) and had a lower median number of grafts (2 vs 3) compared with males. 

Following CABG, women had:

• Higher in-hospital mortality than men (2.2% vs 1.3%, OR 1.74,  p=0.011); and
• Longer hospital stays (median 7 days vs 6days, OR 0.51,  p=0.01).

However, there were no significant differences between the matched cohorts in stroke rates (1.1% vs 0.9%, p=0.56) or 20-year survival.

Meanwhile, among the 1,099 men and 1,152 women who underwent OPCABG, women received fewer grafts (median 2 vs 3, p<0.001) and fewer LIMA grafts (91% vs 94%, p=0.015), although LIMA use was higher than in on-pump CABG, the researchers found. 

Notably, in-hospital mortality was significantly lower in women receiving OPCABG (1.6% vs 3.0%, OR 0.53, p=0.021), compared to those receiving on-pump CABG.

This finding suggests the need for further studies in larger or multicentre datasets, the researchers said.

“Despite a worse preoperative risk profile and worse in-hospital outcomes, the long-term survival in females was comparable to that of males after matching. This finding was observed in the matched population and in the predefined OPCABG sub-analysis. In addition, this finding was consistent when excluding all in-hospital deaths,” the authors noted. 

“This may suggest that, while presenting with worse risk profile and suffering worse in-hospital outcomes, females benefit from an innate long-term resilience as they appeared to do as well as males after discharge.” 

Professor Raimondo Ascione, professor of cardiac surgery and translational research at the University of Bristol, led the research.