BMI and acute kidney injury post transcatheter aortic valve replacement: unveiling the obesity paradox

Abstract

Aims Acute kidney injury (AKI) may complicate transcatheter aortic valve replacement (TAVR) leading to higher mortality. The relationship between AKI, obesity, and mortality, however, is controversial. We sought to investigate the impact of body habitus on the prognostic value of AKI in TAVR. Methods Among the 645 patients who underwent successful TAVR in a single high-volume centre, we retrospectively evaluated the association between AKI-TAVR and 30-day, 6-month, and 1-year mortality, and whether this relationship was affected by BMI. AKI was defined according to the Valve Academic Research Consortium-2 criteria. Patients were categorized into three groups by BMI: low-to-normal weight (<25 kg/m2), overweight (25–30 kg/m2), obese (>30.0 kg/m2). Results Three-hundred and twenty-four (50.2%) patients were low-to-normal weight, 223 (34.6%) overweight, and 98 (15.2%) obese. AKI occurred in 141 (21.9%), similarly across BMI groups. Thirty-day, 6-month, and 1-year mortality rates were 2.2, 3.7, and 7.9%, without differences across BMI groups. Among patients who developed AKI-TAVR, 30-day (8.7 vs. 2.0 vs. 0.0%), 6-month (13.0 vs. 6.1 vs. 4.3%), and 1-year (20.3 vs. 12.2 vs. 4.3%) mortality showed a decreasing trend across increasing BMI categories (all P < 0.05); the same trend was not observed for patients without AKI-TAVR. In multivariate models, AKI was associated with 30-day [odds ratio (OR): 2.46, 95% confidence interval (CI): 1.70–8.67], 6-month (OR: 2.75, 95% CI: 1.32–7.59), and 1-year mortality (OR: 1.84, 95% CI: 1.22–3.71, all P < 0.05). The interaction between AKI and BMI, when added to the models, was consistently significant (all P < 0.05). Conclusion Higher BMI is associated with better survival in TAVR patients who develop AKI.

Heart valve surgery and the obesity paradox: A systematic review

“…Rates of mortality at various time points were either in favour of patients with higher BMI or not significantly different from their normal and low BMI counterparts. 1,11,15,16,21,25,27,29,32,40,41,[43][44][45][46][47][48][49][51][52][53][54][55] Similar to previous studies, it was patients with low BMI that tended to have inferior outcomes. 1,21,29,41,44,45,47,50,51,[53][54][55] Second, postoperative complications such as MI, stroke, reoperation rates, AKI, new renal failure, requirement of dialysis, were postoperative bleeding are either superior in patients with higher BMI or equivalent to their normal BMI counterparts.…”

“…Patients were followed for 1 year with rates of mortality, collected MI, stroke, AKI and bleeding complications provided. 43 A study conducted at our centre (El-Andari et al) retrospectively reviewed the outcomes of 701 patients undergoing MV repair surgery at our institution. Patient groups included BMI <20 kg/m 2 in the patients with underweight group, BMI 20-24.9 kg/m 2 in the patients with normal-weight group, BMI 25-29.9 kg/m 2 in the patients with overweight group, BMI of 30-34.9 kg/m 2 in the patients with obesity group and BMI >35 kg/m 2 in the patients with morbid obesity group.…”

“…32 The studies conducted by Aljanadi, Bruno, De Marzo, Forgie, Ho, Keller, Nazir, Rapetto, Smith and van der Boon did not find significant differences in mortality rates between their groups. 11,15,16,25,40,43,46,48,49,52…”

“…32 The studies conducted by Abawi, Abramowitz, Aljanadi, Boukhris, Bruno, De Marzo, Keller, Konigstein, Om, Owais, Rapetto and van der Boon demonstrated no significant differences in postoperative postoperative complications between different BMI groups. 1,11,15,21,25,27,29,40,41,43,48,50 The previous literature regarding the obesity paradox has focused primarily on CABG and TAVR. 1,9,[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] The literature regarding valve surgery and the obesity paradox has grown in recent years.…”

“…1,21,29,41,44,45,47,50,51,[53][54][55] Second, postoperative complications such as MI, stroke, reoperation rates, AKI, new renal failure, requirement of dialysis, were postoperative bleeding are either superior in patients with higher BMI or equivalent to their normal BMI counterparts. 1,11,15,16,21,25,27,29,32,[40][41][42][43][44][46][47][48][49][50][53][54][55] Finally, two studies demonstrated increased rates of DSWI for patients with higher BMI, although the majority of studies found no significant difference in DSWI rates in contrast to the previous literature. 16,42 A recent study published by our group illustrates the obesity paradox.…”