Heart valve surgery and the obesity paradox: A systematic review

Low body mass index and risk of mortality after mitral transcatheter edge-to-edge repair procedure: The "obesity paradox"

BACKGROUND

Most patients undergoing the mitral transcatheter edge-to-edge repair (TEER) technique are elderly comorbid patients. Low body mass index (BMI) < 23 kg/m2 has been identified in other elderly populations as a risk factor, but has not been studied sufficiently in mitral TEER.

AIMS

We aimed to study the impact of low BMI (23 kg/m2) on the outcome after mitral TEER.

METHODS

Patients undergoing first-time TEER for mitral regurgitation at a single tertiary center were included, with the exclusion of patients with preprocedural hemodynamic instability or missing BMI. The primary endpoint was all-cause mortality. Secondary endpoints were long-term major bleeding or admission with heart failure.

RESULTS

A total of 120 patients (mean age 76 ± 10 years, 76% men) were included in the study. Thirty-nine (31%) had low BMI. Patients with low BMI had a similar symptomatic benefit as patients with BMI ≥ 23 kg/m2 at 1 year regarding decrease in diuretics dose and decrease in New York Heart Association (NYHA) class (p > 0.05). In a multivariable Cox regression analysis, BMI as a continuous variable (hazard ratio [HR]: 0.93 [95% confidence interval, CI: 0.87-0.99], p = 0.03) and low BMI (HR: 1.99 [95% CI: 1.12-3.52], p = 0.02) were associated with the primary outcome. Low BMI was not significantly associated with major bleeding (subdistribution hazard ratio [SHR]: 2.39 [95% CI: 0.96-5.97], p = 0.06) or admission with heart failure (SHR: 1.06 [95% CI: 0.61-1.88], p = 0.83) during follow-up with univariable competing risk regression analysis.

CONCLUSION

Low BMI is a risk factor for mortality after mitral valve TEER, confirming the presence of an "obesity paradox" in this population and should receive attention in patient selection.

Optimizing aortic valve prosthesis selection in patients with obesity: Institutional experience with multidisciplinary perspective

BACKGROUND

Aortic valve diseases are life-threatening conditions with increasing prevalence worldwide. Risk factors include gender, age, hypertension, dyslipidemia, and type 2 diabetes. Obesity is closely related to these risk factors and has been linked to a higher risk of developing aortic valve diseases. However, there is no specific guideline for managing aortic valve disease in patients with obesity, and the choice of valve type remains uncertain.

METHODS

A total of 130 patients with obesity who met the inclusion criteria underwent surgical aortic valve replacement. The patients were divided into two groups based on the type of prosthesis used. Among the study cohort, 50 patients received a bioprosthetic valve, while 80 patients received a mechanical valve. We compared these groups in terms of perioperative characteristics and follow-up results. Statistical significance was determined using a p-value threshold of 0.05.

RESULTS

There were no significant differences in age, gender, body mass index, or cardiac comorbidities between the two groups. Preoperative blood results and echo findings also showed no significant differences. Intraoperative characteristics and postoperative outcomes, including mortality and acute kidney injury, did not differ significantly between the groups. In addition, BHVG patients had shorter ICU stays compared to MHVG patients without significance.

CONCLUSION

Deliberate consideration is crucial when selecting valves for obese patients, particularly those with class II obesity. This is due to the potential influence of obesity on valve types, as well as the need to account for the possibility of bariatric surgery and its potential effects.

Sacrificial scaffold-assisted direct ink writing of engineered aortic valve prostheses

Heart valve disease has become a serious global health problem, which calls for numerous implantable prosthetic valves to fulfill the broader needs of patients. Although current three-dimensional (3D) bioprinting approaches can be used to manufacture customized valve prostheses, they still have some complications, such as limited biocompatibility, constrained structural complexity, and difficulty to make heterogeneous constructs, to name a few. To overcome these challenges, a sacrificial scaffold-assisted direct ink writing approach has been explored and proposed in this work, in which a sacrificial scaffold is printed to temporarily support sinus wall and overhanging leaflets of an aortic valve prosthesis that can be removed easily and mildly without causing any potential damages to the valve prosthesis. The bioinks, composed of alginate, gelatin, and nanoclay, used to print heterogenous valve prostheses have been designed in terms of rheological/mechanical properties and filament formability. The sacrificial ink made from Pluronic F127 has been developed by evaluating rheological behavior and gel temperature. After investigating the effects of operating conditions, complex 3D structures and homogenous/heterogenous aortic valve prostheses have been successfully printed. Lastly, numerical simulation and cycling experiments have been performed to validate the function of the printed valve prostheses as one-way valves.

Effect of body mass index on clinical outcomes after robotic cardiac surgery: is there an obesity paradox?

BACKGROUND

To investigate the effect of body mass index (BMI) on clinical outcomes after robotic cardiac surgery, and to explore the postoperative obesity paradox.

METHODS

The data of 146 patients who underwent robotic cardiac surgery under cardiopulmonary bypass (CPB) from July 2016 to June 2022 in Daping Hospital of Army Medical University were retrospectively analyzed, and their demographic data and related clinical data were statistically analyzed. The mean age was (42.88 ± 13.01) years, 55 (37.67%) were male and 91 (62.33%) were female. Patients were divided into 3 groups according to preoperative BMI: lean group (BMI < 18.5 kg/m²; n = 17; 11.64%), normal group (BMI 18.5 kg/m² to 23.9 kg/m²; n = 81; 55.48%), and overweight and obese group (BMI ≥ 24 kg/m²; n = 48; 32.88%). Multivariate analysis was performed to compare clinical outcomes across BMI groups.

RESULTS

Preoperative data in different BMI groups showed that there were statistically significant differences in age, height, weight, body surface area (BSA), diabetes, left atrial anteroposterior diameter (LAD), triglyceride (TG), and high-density lipoprotein (HDL) (all P < 0.05). Postoperative clinical outcomes showed that there was no statistical difference between the lean group and the normal group; the intensive care unit stay and postoperative hospital stay in the overweight and obese group were significantly higher than those in the normal group (P < 0.05), and the risk of postoperative cardiac surgery-related acute kidney injury (CSA-AKI) was significantly increased (P = 0.021); further Multiple Binary Logistic Regression Analysis suggested that preoperative TG (OR = 1.772, 95% CI 1.068-2.942, P = 0.027) and operation time ≥ 300 min (OR = 3.823, 95% CI 1.098-13.308, P = 0.035) were independent risk factors for postoperative CSA-AKI.

CONCLUSIONS

Overweight and obese patients had significantly prolonged intensive care unit stay and postoperative hospital stay after robotic cardiac surgery, and significantly increased incidence of postoperative CSA-AKI, which did not support the obesity paradox; preoperative TG and operation time ≥ 300 min were independent risk factors for postoperative CSA-AKI.

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.

A systematic review and meta-analysis of the effect of obesity on patients undergoing lower extremity revascularization

OBJECTIVE

In the present review, we assessed the effect of obesity on clinical outcomes for patients with peripheral arterial disease who had undergone endovascular or open lower extremity revascularization surgery.

METHODS

A systematic search strategy of MEDLINE, EMBASE, CINAHL, Web of Science, and Cochrane Library was conducted. The included studies had compared obese and nonobese cohorts with peripheral arterial disease who had undergone endovascular or open lower extremity revascularization. The outcomes included mortality, major adverse cardiovascular events, major adverse limb events, surgical site infections, endovascular access site complications, and perioperative complications.

RESULTS

Eight studies were included with 171,648 patients. The obese patients (body mass index ≥30 kg/m²) were more likely to be women, to have diabetes, and to have more cardiovascular comorbidities despite being younger. No association was found between obesity and peripheral arterial disease severity. Obesity was associated with an overall 22% decreased mortality risk after lower extremity revascularization (risk ratio [RR], 0.78; 95% confidence interval [CI], 0.71-0.85; P < .001; I² = 0%; GRADE (grading of recommendations assessment, development, evaluation), very low quality). A subgroup analysis by intervention type showed similar findings (endovascular: RR, 0.79; 95% CI, 0.71-0.87; P < .001; I² = 0%; open: RR, 0.70; 95% CI, 0.51-0.95; P = .024; I² = 43%). Obesity was associated with a 14% decreased risk of major adverse cardiovascular events for open surgery only (RR, 0.86; 95% CI, 0.76-0.98; P = .021; I² = 0%; GRADE, very low quality). Obesity was associated with an increased risk of surgical site infections pooled across intervention types (RR, 1.69; 95% CI, 1.34-2.14; P < .001; I² = 78%; GRADE, very low quality). No association was found between obesity and major adverse limb events (RR, 1.02; 95% CI, 0.93-1.11; P = .73; I² = 15%; GRADE, very low quality) or endovascular access site complications (RR, 1.11; 95% CI, 0.76-1.63; P = .58; I² = 86%; GRADE, very low quality). Pooled perioperative complications did not differ between the obese and nonobese cohorts (RR, 1.04; 95% CI, 0.84-1.28; P = .73; I² = 92%; GRADE, very low quality).

CONCLUSIONS

Obesity was associated with reduced mortality risk with both endovascular and open surgery, although a reduction in major adverse cardiovascular events was only observed with open surgery. In addition, obese patients had an increased risk of surgical site infections. Obesity was not associated with major adverse limb events, endovascular access site complications, or perioperative complications. The GRADE quality of evidence was very low. The findings from the present review suggest a survival advantage for obese patients with peripheral arterial disease. Future studies could focus on prospectively investigating the effect of obesity on peripheral arterial disease outcomes. A nuanced evaluation of body mass index as a preoperative risk factor is warranted.

The influence of metabolic syndrome in heart valve intervention. A multi-centric study

BACKGROUND

The effect of metabolic syndrome (MetS), defined as insulin resistance along with two or more of: obesity, atherogenic dyslipidaemia and elevated blood pressure, on postoperative complications after isolated heart valve intervention remains controversial. We hypothesized that MetS may negatively influence the postoperative course in these patients.

METHODS

Patients from 10 cardiac units who underwent isolated valve intervention (mitral± $\pm $  tricuspid repair/replacement (mitral valve surgery [MVS]) or surgical aortic valve replacement (SAVR), or transcatheter aortic valve replacement (TAVR) were included. MetS was defined according to the World Health Organization criteria. Primary outcome was in-hospital mortality and overall postoperative length of stay (LOS). Relevant postoperative complications were also recorded.

RESULTS

From 2010 to 2019, 17,283 patients underwent valve intervention. The MVS, SVAR, and TAVR accounted for the 39.4%, 48.2%, and 12.3% respectively of the whole. MetS compared to no-MetS was associated to higher mortality in the MVS group (6.5% vs. 2%, p < .001), but not in the SAVR and TAVR group. In both surgical cohorts, MetS was associated with increased complications including red blood cells transfusion, renal failure, mechanical ventilation time, intensive care and overall postoperative LOS (11 (9) vs. 10 (6), p < .001 and 10 (6) versus 10 (5) days, p = .002, MVS and [SAVR]). No differences were found in the TAVR cohort, with similar mortality and complications.

CONCLUSION

MetS was associated to more postoperative complications, with higher mortality in the MVS group. In the TAVR cohort, postoperative complications and mortality rate did not differ between patients with and without MetS, however LOS was longer in the MetS group.

Impact of Obesity on Early In-Hospital Outcomes after Coronary Artery Bypass Grafting Surgery in Acute Coronary Syndrome: A Propensity Score Matching Analysis

Recent advances in perioperative care have considerably improved outcomes after coronary artery bypass graft (CABG) surgery. However, obesity can increase postoperative complication rates and can lead to increased morbidity and mortality. Between June 2011 and October 2019, a total of 1375 patients with acute coronary syndrome (ACS) underwent cardiac surgery and were retrospectively analyzed. Patients were divided into 2 groups: non-obese (body mass index (BMI) < 30 kg/m2, n = 967) and obese (BMI ≥ 30 kg/m2, n = 379). Underweight patients (n = 29) were excluded from the analysis. To compare the unequal patient groups, a propensity score-based matching (PSM) was applied (non-obese group (n = 372) vs. obese group (n = 372)). The mean age of the mentioned groups was 67 ± 10 (non-obese group) vs. 66 ± 10 (obese group) years, p = 0.724. All-cause in-hospital mortality did not significantly differ between the groups before PSM (p = 0.566) and after PSM (p = 0.780). The median length of ICU (p = 0.306 before PSM and p = 0.538 after PSM) and hospital stay (p = 0.795 before PSM and p = 0.131 after PSM) was not significantly higher in the obese group compared with the non-obese group. No significant differences regarding further postoperative parameters were observed between the unadjusted and the adjusted group. Obesity does not predict increased all-cause in-hospital mortality in patients undergoing CABG procedure. Therefore, CABG is a safe procedure for overweight patients.