Transcatheter aortic valve implantation (TAVI) decreases mortality in high-risk patients with severe aortic stenosis, but it remains unclear if female gender is associated with more favorable outcomes after TAVI. All patients who underwent TAVI at a single institution were retrospectively analyzed and stratified by gender. Procedural, in-hospital, 30-day, and 1-year outcomes were defined according to the second Valve Academic Research Consortium. The primary end point was all-cause mortality at 1 year. Kaplan–Meier survival analysis and multivariable Cox proportional hazards regression were conducted. Overall, 755 patients underwent TAVI and were included in the study; 50.7% were women. Average age was 83.0 ± 7.7 years, with a mean Society of Thoracic Surgeons score of 8.9 ± 4.6. Women were older than men and more likely to be black. Most co-morbidities were less common among women, and they were more likely than men to suffer both in-hospital (8.4% vs 4.3%, p = 0.021) and 30-day (9.4% vs 5.4%, p = 0.035) all-cause mortality. Life-threatening bleeding, transfusion, and iliofemoral dissection or perforation were more common among women. There was no difference in mortality between women and men at 1 year (20.6% vs 21.5%, log-rank p = 0.87). After multivariable adjustment, however, female gender was independently associated with lower mortality at 1 year after TAVI. In conclusion, despite higher rates of major bleeding, vascular complications, and 30-day mortality, female gender was independently associated with improved survival at 1 year after TAVI.
The emergence of transcatheter aortic valve implantation (TAVI) as the preferred therapeutic option for patients with severe AS at high or extreme risk for surgery offers an opportunity to examine gender disparities in outcomes. The evidence base for the impact of gender upon TAVI, however, is still evolving. Some studies suggest improved long-term survival among women, whereas other studies report long-term survival that is similar to men. In general, previous studies also suggest more vascular and bleeding complications in women than those in men. We therefore sought to examine gender differences in co-morbidities, complications, and outcomes among patients undergoing TAVI at a single center.
Methods
From May 2007 to January 2015, patients with severe, symptomatic AS who underwent TAVI at MedStar Washington Hospital Center in Washington, DC, were included in this retrospective analysis. The Institutional Review Board at MedStar Washington Hospital Center and MedStar Cardiovascular Research Network approved this study. A multidisciplinary team that included interventional cardiologists, cardiothoracic surgeons, and imaging specialists determined eligibility for TAVI. Although protocols, access routes, and devices evolved over the time period of the study, all patients were determined to be at extreme risk, high risk, or intermediate risk based upon clinical (e.g., Society of Thoracic Surgeons risk score, frailty) and procedural (e.g., hostile chest, porcelain aorta) considerations. Pre-TAVI evaluation consisted of coronary angiography to detect significant stenoses; transthoracic echocardiography that included measurement of peak and mean aortic gradients, aortic valve area, left ventricular function, and pulmonary artery systolic pressure; and contrast computed tomography with postprocessing reconstructions to assess aortoiliac and aortic annulus diameters.
TAVI procedures were performed under either conscious sedation or general anesthesia in a hybrid cardiac catheterization laboratory. Access sites included transfemoral (either percutaneous or surgical cutdown), transapical, or direct transaortic. In the case of femoral access, preclosure was used with either a Prostar XL or 2 Perclose Proglide 6Fr devices (Abbott Vascular, Redwood, California). TAVI was performed with either balloon-expandable or self-expanding devices and included both early and contemporary versions of the Sapien (Edwards LifeSciences, Irvine, California) and CoreValve (Medtronic, Minneapolis, Minnesota) bioprostheses. A minority of patients also received devices yet to receive US Food and Drug Administration approval: Lotus (Boston Scientific, Marlborough, Massachusetts) and Direct Flow (Santa Rosa, California). Antiplatelet therapy after TAVI consisted of clopidogrel 75-mg daily and aspirin 81-mg daily for 3 to 6 months. Demographic, clinical, imaging, procedural, and follow-up data were prospectively collected by dedicated research personnel and entered into a database. Clinical end points were independently adjudicated by an interventional cardiologist blinded to the outcomes of this study. A dedicated data coordinating center at the MedStar Cardiovascular Research Network performed all data management and analyses.
In addition to in-hospital follow-up, clinical follow-up consisted of office visits or telephone contact at 30 days and 1 year. Clinical end point definitions used in this study were in concordance with the second Valve Academic Research Consortium criteria. This included all-cause mortality, stroke, bleeding, vascular complications, and acute kidney injury. Rates of acute kidney injury are reported only among patients not requiring dialysis before they underwent TAVI. The primary end point of the study was all-cause mortality at 1 year. In addition to using clinical data, mortality events were confirmed through inspection of death certificates and querying of the Social Security Death Index. Postprocedure perivalvular and central aortic regurgitation, in addition to aortic gradients and valve area, were also assessed by transthoracic echocardiography during the index hospitalization.
Continuous variables are presented as mean ± SD; categorical variables are presented as percentages. Differences in continuous variables between groups were compared using the Student t test. Categorical variables were compared using the chi-square test or Fisher’s exact test when appropriate. A p value <0.05 was considered statistically significant. Kaplan–Meier analysis was used to investigate the association of gender with the cumulative incidence of all-cause mortality at 30 days and 1 year. Similar Kaplan–Meier analyses were performed based on stratification by gender and valve type (balloon-expandable vs self-expanding; direct flow excluded from this analysis) and by gender and route of access (transfemoral vs transapical; transaortic excluded from this analysis). Survival curves were compared using the log-rank test. To examine the independent association of female gender with all-cause mortality at 30 days and 1 year, we constructed a multivariable logistic regression model and a multivariable Cox proportional hazard model, respectively. Covariables for the models were selected based on significant univariable p values and overall clinical relevance. Covariables in the model for 30-day all-cause mortality, in addition to gender, included age (per 5 years), transfemoral access, and a history of chronic renal insufficiency. Covariables in the model for all-cause mortality at 1 year included all variables in the 30-day model, in addition to use of a self-expanding valve, left ventricular ejection fraction ≤40%, a history of peripheral vascular disease, and a history of myocardial infarction. Covariables in the models are expressed as odds ratios or hazard ratios with 95% CI. Statistical analyses were performed using SAS, version 9.1 (SAS Institute, Cary, North Carolina).
Results
Overall, 755 patients underwent TAVI and were included in the study; a majority (50.7%) were female. The average age of the cohort was 83.0 ± 7.7 years, with a mean Society of Thoracic Surgeons score of 8.9 ± 4.6. There were important differences in baseline characteristics between women and men, as women were older and more likely to be black. In addition, most co-morbidities were less common among women; this included atrial fibrillation or flutter, chronic renal insufficiency, peripheral vascular disease, left ventricular ejection fraction ≤40%, and current or previous smoking. Women were also less likely to have coronary artery disease or its sequelae, including previous percutaneous coronary intervention, coronary artery bypass grafting, or myocardial infarction. Despite this lesser burden of co-morbid conditions, women still had greater Society of Thoracic Surgeons scores than men: 9.8 ± 4.6 versus 8.0 ± 4.4, p <0.001. Women also demonstrated echocardiographic measurements that indicated more severe AS, including higher mean and peak aortic gradients, faster aortic jet velocity, and smaller aortic valve area than men. These baseline characteristics are displayed in Table 1 .
| Variable | Women (n = 383) | Men (n = 372) | p Value |
|---|---|---|---|
| Age (years) | 83.5 ± 7.7 | 82.4 ± 7.7 | 0.049 |
| Society of Thoracic Surgeons score | 9.8 ± 4.6 | 8.0 ± 4.4 | <0.001 |
| White | 286 (81.3%) | 285 (88.0%) | 0.02 |
| Black | 55 (15.6%) | 29 (9.0%) | 0.009 |
| Hypertension | 342 (92.4%) | 335 (95.4%) | 0.09 |
| Diabetes mellitus | 114 (31.1%) | 124 (35.4%) | 0.38 |
| Chronic obstructive pulmonary disease | 128 (35.0%) | 120 (34.1%) | 0.80 |
| Atrial fibrillation/flutter | 135 (36.5%) | 161 (46.0%) | 0.01 |
| Prior percutaneous coronary intervention | 91 (24.9%) | 127 (36.9%) | <0.001 |
| Prior coronary artery bypass grafting | 70 (19.1%) | 169 (48.3%) | <0.001 |
| Prior myocardial infarction | 50 (13.9%) | 81 (23.8%) | <0.001 |
| Chronic renal insufficiency | 151 (41.8%) | 185 (53.0%) | 0.003 |
| Peripheral vascular disease | 103 (28.4%) | 142 (41.9%) | <0.001 |
| Current or prior smoker | 73 (23.9%) | 131 (42.7%) | <0.001 |
| Left ventricular ejection fraction ≤40% | 59 (16.2%) | 105 (30.1%) | <0.001 |
| Mean aortic gradient (mm Hg) | 50.1 ± 13.3 | 44.9 ± 11.5 | <0.001 |
| Peak aortic gradient (mm Hg) | 73.7 ± 19.4 | 67.8 ± 13.6 | <0.001 |
| Peak aortic velocity (m/s) | 4.4 ± 0.6 | 4.2 ± 0.5 | <0.001 |
| Aortic valve area (cm 2 ) | 0.63 ± 0.13 | 0.70 ± 0.13 | <0.001 |
| Pulmonary artery systolic pressure (mm Hg) | 45.6 ± 16.6 | 44.2 ± 15.5 | 0.31 |
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