Effect of BMI on patients undergoing transcatheter aortic valve implantation: A systematic review and meta-analysis

Background: The relationship of body mass index (BMI) and an "obesity paradox" with cardiovascular risk prediction is controversial. This systematic review and meta-analysis aims to compare the associations of different BMI ranges on transcatheter aortic valve implantation (TAVI) outcomes.

Methods: International databases, including PubMed, the Web of Science, and the Cochrane Library, were systematically searched for observational and randomized controlled trial studies investigating TAVI outcomes in any of the four BMI categories: underweight, normal weight, overweight, and obese with one of the predefined outcomes. Primary outcomes were in-hospital, 30-day, and long-term all-cause mortality. Random-effects meta-analysis was performed to calculate the odds ratio (OR) or standardized mean differences (SMD) with 95% confidence interval (CI) for each paired comparison between two of the BMI categories.

Results: A total of 38 studies were included in our analysis, investigating 99,829 patients undergoing TAVI. There was a trend toward higher comorbidities such as hypertension, diabetes, and dyslipidemia in overweight patients and individuals with obesity. Compared with normal-weight, patients with obesity had a lower rate of 30-day mortality (OR 0.42, 95% CI 0.25-0.72, p < 0.01), paravalvular aortic regurgitation (OR 0.63, 95% CI 0.44-0.91, p = 0.01), 1-year mortality (OR 0.48, 95% CI 0.24-0.96, p = 0.04), and long-term mortality (OR 0.69, 95% CI 0.51-0.94, p = 0.02). However, acute kidney injury (OR 1.16, 95% CI 1.04-1.30, p = 0.01) and permanent pacemaker implantation (OR 1.25, 95% CI 1.05-1.50, p = 0.01) odds were higher in patients with obesity. Noteworthy, major vascular complications were significantly higher in underweight patients in comparison with normal weight cases (OR 1.62, 95% CI 1.07-2.46, p = 0.02). In terms of left ventricular ejection fraction (LVEF), patients with obesity had higher post-operative LVEF compared to normal-weight individuals (SMD 0.12, 95% CI 0.02-0.22, p = 0.02).

Conclusion: Our results suggest the presence of the "obesity paradox" in TAVI outcomes with higher BMI ranges being associated with lower short- and long-term mortality. BMI can be utilized for risk prediction of patients undergoing TAVI.