Underweight TAVR patients face higher mortality risk—obesity makes no significant impact
Overweight and obese patients who undergo transcatheter aortic valve replacement (TAVR) are associated with outcomes comparable to those with a healthy body mass index (BMI), according to new data published in The American Journal of Cardiology.[1] Patients who are underweight at the time of treatment, however, may face a heightened long-term mortality risk.
“Recent literature highlights an intriguing paradox in the relationship between obesity and outcomes in cardiovascular diseases, such as myocardial infarction and aortic stenosis,” wrote first author Jakob J. Reichl, MD, a researcher with the University of Basel in Switzerland, and colleagues. “Specifically, prior studies have reported lower mortality and superior outcomes in patients with higher BMI, even after TAVR—a phenomenon referred to as the ‘obesity paradox.’ The mechanisms underlying this paradox remain unclear and warrant further investigation. Similarly, underweight patients have been associated with worse outcomes following TAVR or surgical aortic valve replacement.”
Reichl et al. explored registry data from more than 6,000 TAVR patients treated in Switzerland or Germany from 2008 to 2024. All patients were categorized based on their baseline BMI as being underweight (<18.5 kg/m2), normal weight (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²) or obese (≥30 kg/m²).
Overall, 1.8% of patients were underweight, 38.8% had a normal weight, 38.6% were overweight and 20.6% were obese. After 30 days, the rates of all-cause mortality, stroke and bleeding events were not significantly different for any of these groups.
Underweight patients, meanwhile, were linked to a much higher mortality rate than normal-weight patients after one year (23.7% vs. 13.2%) and after five years (53.2% vs. 44%).
Obese patients, the authors noted, still had a mortality rate comparable to normal-weight patients after one year and then after five years.
“A key finding of our study is the demonstration of comparable rates of procedural success and short-term clinical outcomes among obese, overweighted, underweighted, and normal-weight patients,” the authors wrote. “These findings challenge traditional assumptions about BMI-related procedural risk and support the inclusion of diverse BMI profiles in TAVR treatment guidelines.”
The group also emphasized that these data “pose a significant challenge to the ‘obesity paradox.’”
“The absence of significant differences in mortality rates herein suggest that BMI alone may not adequately capture the heterogeneity of patient characteristics and outcomes,” they wrote. “These findings raise important questions about the validity of the obesity paradox in the context of TAVR and emphasize the need for further prospective research to explore the relationship between BMI and long-term survival.”
When it comes to the observed difference in outcomes for underweight patients, on the other hand, Reichl and colleagues believe the connection should lead to additional research.
“Frailty and cachexia, often-used markers of advanced heart disease, further highlight the need for tailored interventions to optimize outcomes for underweight patients undergoing TAVR,” the group wrote.
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Michael has more than 18 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.