Does the "obesity paradox" exist after transcatheter aortic valve implantation?

Abstract

Background: Transcatheter aortic valve implantation (TAVI) for symptomatic aortic stenosis is considered a minimally invasive procedure. Body mass index (BMI) has been rarely evaluated for pulmonary complications after TAVI. This study aimed to assess the influence of BMI on pulmonary complications and other related outcomes after TAVI.

Methods: The clinical data of 109 patients who underwent TAVI in our hospital from May 2018 to April 2021 were retrospectively analyzed. Patients were divided into three groups according to BMI: low weight (BMI < 21.9 kg/m², n = 27), middle weight (BMI 21.9-27.0 kg/m², n = 55), and high weight (BMI > 27.0 kg/m², n = 27); and two groups according to vascular access: through the femoral artery (TF-TAVI, n = 94) and through the transapical route (TA-TAVI, n = 15). Procedure endpoints, procedure success, and adverse outcomes were evaluated according to the Valve Academic Research Consortium (VARC)-2 definitions.

Results: High-weight patients had a higher proportion of older (p < 0.001) and previous percutaneous coronary interventions (p = 0.026), a higher percentage of diabetes mellitus (p = 0.026) and frailty (p = 0.032), and lower glomerular filtration rate (p = 0.024). Procedure success was similar among the three groups. The 30-day all-cause mortality of patients with low-, middle-, and high weights was 3.7% (1/27), 5.5% (3/55), and 3.7% (1/27), respectively. In the multivariable analysis, middle- and high-weight patients exhibited similar overall mortality (middle weight vs. low weight, p = 0.500; high weight vs. low weight, p = 0.738) and similar intubation time compared with low-weight patients (9.1 ± 7.3 h vs. 8.9 ± 6.0 h vs. 8.7 ± 4.2 h in high-, middle-, and low-weight patients, respectively, p = 0.872). Although high-weight patients had a lower PaO₂/FiO₂ ratio than low-weight patients at baseline, transitional extubation, and post extubation 12th hour (p = 0.038, 0.030, 0.043, respectively), there were no differences for post extubation 24th hour, post extubation 48th hour, and post extubation 72nd hour (p = 0.856, 0.896, 0.873, respectively). Chronic lung disease [odds ratio (OR) 8.038, p = 0.001] rather than high weight (OR 2.768, p = 0.235) or middle weight (OR 2.226, p = 0.157) affected postoperative PaO₂/FiO₂ after TAVI.

Conclusions: We did not find the existence of an obesity paradox after TAVI. BMI had no effect on postoperative intubation time. Patients with a higher BMI should be treated similarly without the need to deliberately extend the intubation time for TAVI.

Keywords: Aortic stenosis; Body mass index; Intubation time; TAVI.