Meta-analysis: Women Fare Better Than Men After TAVR Despite More Complications

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Although men experience fewer bleeding and major vascular complications after transcatheter aortic valve replacement (TAVR) compared with women, they are also less likely to survive at both 30 days and 1 year, according to a meta-analysis published online September 24, 2013, ahead of print in Circulation: Cardiovascular Interventions.

Researchers led by Mao Chen, MD, PhD, of Sichuan University (Chengdu, China), culled 27 papers from the literature that included 9,119 patients (46% men) undergoing TAVR for aortic stenosis.

In the 6 studies that directly compared men and women in terms of major bleeding, men were at lower risk (12.8% vs. 15.3%; RR 0.81; 95% CI 0.68-0.96; P = 0.02). Results were not maintained when the 2 largest studies were removed from the analysis. Five studies evaluated major vascular complications by patient sex, and again men had lower risk (6.1% vs. 11.3%; RR 0.49; 95% CI 0.37-0.66; P < 0.00001).

With regard to permanent pacemaker implantation, 9 studies reported data. This complication was common in studies that predominantly used the CoreValve device (Medtronic, Minneapolis, MN) and higher in men compared with women (31.3% vs. 24.7%; RR 1.29; 95% CI 1.13-1.47; P = 0.0002). This difference was not seen in studies that used the Sapien valve (Edwards Lifesciences, Irvine, CA; 8.0% vs. 7.4%; RR 1.06; 95% CI 0.75-1.48; P = 0.75).

Incidence of stroke, reported in 4 studies, did not differ between men and women after TAVR (2.2% vs. 1.7%; RR 1.39; 95% CI 0.71-2.74; P = 0.34).

Thirty-day mortality was higher in men (9.3%) compared with women (6.9%) in 13 studies (RR 1.37; 95% CI 1.07-1.76; P = 0.01). Similar results were seen at 1-year in 16 studies (22.0% vs. 16.9%; RR 1.30; 95% CI 1.14-1.49; P = 0.0002). At both follow-up durations, the findings were confirmed by omitting the 2 smallest studies.

Baseline comparative data between men and women were available in 5 studies. Men were more likely to have diabetes, COPD, coronary artery disease, peripheral vascular disease, and prior MI and PCI.

Unexplained Confounders

The findings are in line with those from the sex-specific analysis of the PARTNER trial, Dr. Chen and colleagues write, offering several explanations for the “phenomenon:”

  • Female sex was a risk factor of some complications, but these complications did not commonly lead to death
  • Pathophysiological characteristics may serve as a possible underlying mechanism (ie, women may have a lower prevalence of and less severe cardiac remodeling and fibrosis)
  • Differences in baseline characteristics between men and women may play a larger part than gender alone

In a telephone interview with TCTMD, Peter C. Block, MD, of Emory University School of Medicine (Atlanta, GA), said “it’s a little bit of a mystery why women should do better.” Since the majority of TAVR patients die from comorbidities rather than cardiac issues, he observed, “men with aortic stenosis [may] have more other stuff going on that ultimately will cause them to [die].”

Josep Rodés-Cabau, MD, of Laval University (Quebec City, Canada), agreed, offering additional reasons.

“Women have a smaller annulus, [so] maybe we are obtaining better results in terms of valve hemodynamics with less aortic insufficiency,” he told TCTMD in a telephone interview. A study from his group in Canada was included in the meta-analysis, but “when we [adjusted for] these factors and the hemodynamic results including aortic regurgitation, still women did better than men. There is something that we are not able to understand; some confounder that seems to play a positive role for women versus men with this technology,” he said.

In general, women have been known to have higher bleeding rates and vascular access site complication rates and “it’s always been attributed to them having smaller blood vessels,” according to Stephen G. Ellis, MD, of the Cleveland Clinic (Cleveland, OH). “I don’t think it’s a surprise that men have worse long-term outcomes, although the reason isn’t clear,” he told TCTMD in a telephone interview.

Risk Factor Management Deserves More Attention

But in terms of clinical implications, “you can’t do anything about the biology,” Dr. Ellis continued.

Additionally, paravalvular leak will not be a big issue with second-generation devices, and if coronary and renal disease are the real issue, “then maybe we need to be more attentive to risk factor management for coronary disease in these patients,” he said. “Sometimes we get wrapped up in treating the principle problem that a patient might have. So if a patient has aortic stenosis then all the focus is on the aortic stenosis. They may have coronary disease too, but sometimes that gets put on the back burner.”

The good news, according to Dr. Block, relates to risk management for TAVR in women in the future. “We’ve always worried [about] women because they have smaller arteries and vascular tissue, and because they overall don’t do as well with heart surgery as men in general,” he said. But they “are doing better with transcatheter valve replacement which gives us reassurance about choosing women who are smaller or with worse tissue. . . . It may push some women to transcatheter valve replacement that we might have operated on as we push toward lower risk patients as we go forward.”

Dr. Rodés-Cabau suggested that larger studies will have to validate the findings in the meta-analyses. “Maybe there are some factors that we’re not taking into account that can explain the difference between men and women. There might be some factors that you can control, modify, or improve,” he concluded.

Source:

Zhao Z-G, Liao Y-B, Peng Y, et al. Sex-related differences in outcomes after transcatheter aortic valve implantation: A systematic review and meta-analysis. Circ Cardiovasc Interv. 2013;Epub ahead of print.

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Disclosures
  • Drs. Chen, Block, and Ellis report no relevant conflicts of interest.
  • Dr. Rodés-Cabau reports serving as a consultant to Edwards Lifesciences and St. Jude Medical.

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