Background:
An “obesity paradox” has been described after transcatheter aortic valve implantation (TAVI), suggesting lower mortality in patients with higher body mass index (BMI) despite higher comorbidity. In contrast, underweight consistently predicts adverse outcomes.
Objectives:
To evaluate the impact of obesity (BMI ≥30 kg/m²) and underweight (BMI <20 kg/m²) on 30-day clinical outcomes after transfemoral TAVI and to reassess the obesity paradox after multivariable adjustment.
Methods:
This prespecified subgroup analysis included all patients of the randomized DOUBLE-CHOICE trial, comparing two transcatheter heart valves and two anaesthesia strategies (minimalist approach including local anaesthesia only without sedation vs. standard-of-care with sedation). The primary endpoint for the comparison of anaesthesia strategies was a 30-day composite of all-cause mortality, vascular and bleeding complications, infections requiring antibiotic therapy and neurologic events. Associations were evaluated using multivariable logistic regression adjusted for age, sex, frailty, diabetes, hypertension, chronic kidney disease, and the anaesthesia strategy, to further assess the obesity paradox.
Results:
Among 738 patients (BMI ≥30: 193; <30: 545), obese patients showed lower event rates for the 30-day composite endpoint (15.2% vs 27.6%, p<0.001). After multivariable adjustment, obesity remained independently associated with lower risk of the primary composite endpoint (adjusted OR 0.48, 95% CI 0.30–0.75, p=0.002), whereas age, sex, frailty, diabetes, hypertension, renal function and the anaesthesia strategy were not significant predictors. Paradoxically, frailty was more common among obese patients (61.7% vs 53.2%, p=0.042).
In contrast, underweight (n=23) was strongly associated with excess risk: The primary endpoint occurred in 55.0% vs 23.4% (p=0.003), major vascular complications in 27.8% vs 2.3% (p<0.001), and bleeding in 26.3% vs 6.3% (p<0.001), respectively.
Conclusion:
In this randomized TAVI population, obesity was independently associated with lower rates of adverse outcomes at 30 days, whereas underweight conferred markedly increased procedural and vascular risk. The apparent “obesity paradox” persisted after multivariable adjustment, suggesting that obesity may reflect greater physiological reserves in this elderly population. Conversely, underweight represents a high-risk phenotype that may benefit from tailored procedural and peri-interventional management.
