Registry Shows Better Survival for Women vs. Men After TAVR

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Among patients with severe aortic stenosis, women have better short- and long-term survival after transcatheter aortic valve replacement (TAVR) than men. The findings, from an observational study published online July 18, 2012, ahead of print in the Journal of the American College of Cardiology, lend support to the idea that women may be better served by TAVR than surgery.

Karin H. Humphries, DSc, of the University of British Columbia (Vancouver, Canada), and colleagues evaluated outcomes in 641 consecutive patients (51.3% women) undergoing TAVR between January 2005 and September 2011 at St. Paul’s Hospital (Vancouver) and the Quebec Heart and Lung Institute (Quebec City, Canada). All were at high or prohibitive risk for surgery and selected for TAVR by a multidisciplinary heart team. Median follow-up duration was 302 days.

At 30 days after TAVR, major vascular complication and transfusion rates were higher in women, with a trend toward increased bleeding. Women, on the other hand, had much lower mortality. Stroke and need for permanent pacemaker did not differ by sex (table 1).

Table 1. Short-Term Outcomes

 

Women
(n = 306)

Men
(n = 278)

P Value

Major Vascular Complication

12.4%

5.4%

0.003

Major/Life-Threatening Bleeding

21.6%

15.8%

0.08

Blood Transfusion

9.5%

3.6%

0.005

Major Stroke

2.0%

1.8%

0.89

New Pacemaker

6.4%

4.3%

0.24

Mortality at 30 Days

6.5%

11.2%

0.05


Kaplan-Meier analysis showed a survival advantage for women at 1 year (82.7% vs. 72.5% for men) and at 2 years (72.1% vs. 61.7% for men; log-rank P = 0.007). The unadjusted risk of 2-year all-cause mortality was lower in women compared with men (HR 0.64; 95% CI 0.46-0.88). When researchers adjusted not only for age, site, access route, and postprocedural complications but also baseline valve characteristics, surgical risk, mitral regurgitation grade, and comorbidities, women still had a lower risk of mortality (HR 0.55; 95% CI 0.37-0.81; P = 0.003).

Baseline characteristics varied considerably between the sexes. Compared with men, women had higher mean aortic gradients, worse renal function, more porcelain aortas, and increased prevalence of frailty. But female patients also had better ventricular function at baseline and fewer comorbidities.

Backing Up PARTNER

The current findings mirror those of the PARTNER 1A trial, which contained a prespecified subgroup analysis on sex differences in mortality (Smith CR. N Engl J Med. 2011;364:2187-2198). In that study, women seemed to derive a greater survival benefit from TAVR vs. surgery (RR 0.68; 95% CI 0.44-1.04) than did men (RR 1.17; 95% CI 0.84-1.63; P = 0.05 for interaction). Within the TAVR arm, women experienced a lower unadjusted rate of 1-year mortality compared with men at 18.4% vs. 28.4% (P = 0.03).

Considered together, results from the 2 studies suggest that “TAVR might be the preferred mode of treatment in elderly women with symptomatic severe [aortic stenosis],” the investigators conclude.

In a telephone interview with TCTMD, Dr. Humphries said, “[I]f anything, women do worse [periprocedurally]. They require more blood transfusions. They’re more likely to have vascular complications. If we could solve that problem, the gap. . . would be even greater in favor of women.”

She observed that for both PCI and CABG, outcomes were initially worse for women than men but have started to improve over the years. “Here we’ve got a new treatment modality where out of the gate women are doing better. I think it’s just amazing,” Dr. Humphries commented.

‘Good News for Women’

Alexandra J. Lansky, MD, of the Yale School of Medicine (New Haven, CT), pointed out in a telephone interview with TCTMD that this series stands as the largest to date looking at sex differences in the procedure. Though not a direct comparison between TAVR and surgical repair, the study holds value, she said: “The larger the number of patients, the more convincing the evidence. From my perspective, it’s contributing to the [credibility] of the benefit in female patients.”

While women still face a higher rate of vascular complications, Dr. Lansky observed, they show “a persistent mortality benefit. At the end of the day, we can say that the benefit in females is at least as good as in males, and there’s growing evidence that women may do better.”

“For once, we’re seeing [females] benefit [more] from a minimally invasive procedure instead of males,” she concluded. “I think most patients, given the choice, would choose a minimally invasive approach, and having a safe and effective option for women is very encouraging in that regard.”

Philippe Généreux, MD, of Columbia University Medical Center (New York, NY), described the findings as “confirmatory.”

He told TCTMD in a telephone interview that the study reveals a pattern that has been seen in other procedures such as PCI. Women appear more “vulnerable in the acute phase,” Dr. Généreux said. “But the paradox is they survive longer.”

The long-term advantage for women may “influence the decisional tree,” he commented. “This is especially important when both options are good. Why not pick the one that’s less invasive? This is good news for women.” Dr. Généreux reported that new analyses from PARTNER 1A will soon shed light on how patient sex affects outcomes from surgery vs. TAVR via the transapical or transfemoral routes.

Dr. Humphries added that results could potentially vary by sex depending on whether patients received balloon-expandable or self-expanding valves.

Why the Disparity?

As to why survival for women and men is so different after TAVR, “at this point it’s all speculative,” Dr. Lansky said. The theory that women may have better left ventricular remodeling after TAVR is “interesting,” she noted, though that would not explain why the sex difference is so visible after TAVR but not surgery.

“That’s actually a very good point,” Dr. Humphries agreed, noting that the mechanism would be expected to play out similarly in both procedures. She added that, likewise, her coauthors are “at a loss to explain [the sex difference].”

Dr. Généreux commented that echocardiographic findings might help elucidate how men and women differ. In addition, women tend to have smaller body size and as such might have smaller annuli. Therefore, “there’s probably more of a chance we’ll find a valve that’s going to fit them,” he noted, adding that in men, there may be more of a tendency to “push the envelope” for a large annulus.

Study Details

The majority of patients (97%) were treated with balloon-expandable valves, including the Cribier-Edwards, Sapien, and Sapien XT devices (Edwards Lifesciences, Irvine, CA). The remainder received self-expanding valves such as CoreValve (Medtronic, Minneapolis, MN), Portico (St. Jude Medical, St. Paul, MN), and Centera (Edwards Lifesciences). Transfemoral access was preferred except in patients with unsuitable iliofemoral arteries; the transapical approach was used in 51.7% of women and 38.1% of men (P < 0.001).

 


Source:
Humphries KH, Toggweiler S, Rodés-Cabau J, et al. Sex differences in mortality after transcatheter aortic valve replacement for severe aortic stenosis. J Am Coll Cardiol. 2012;Epub ahead of print.

 

 

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Disclosures
  • Dr. Humphries reports receiving grant support from the Michael Smith Foundation for Health Research (Vancouver, Canada).
  • Dr. Lansky reports no relevant conflicts of interest.
  • Dr. Généreux reports receiving speaker honoraria, consulting fees, and a research grant from Edwards Lifesciences.

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