Impact of obesity on adverse in-hospital outcomes in patients undergoing percutaneous mitral valve edge-to-edge repair using MitraClip® procedure - Results from the German nationwide inpatient sample

Updates on obesity and the obesity paradox in cardiovascular diseases

The prevalence of obesity has reached pandemic proportions worldwide and certainly in the United States. Obesity is a well-established independent risk factor for development of many cardiovascular diseases (CVD), including heart failure, coronary heart disease, atrial fibrillation, and hypertension. Therefore, it is logical to expect obesity would have a strong correlation with CVD mortality. However, a substantial body of literature demonstrates a paradox with improved prognosis of overweight and obese patients with established CVD compared to lean patients with the identical CVD. Surprisingly, similar data has also shown that cardiovascular fitness, rather than weight loss alone, influences the relationship between obesity and mortality in those with established CVD. The impact of fitness, exercise, physical activity (PA), and weight loss and their relationship to the obesity paradox are all reviewed here.

Survival benefit of overweight patients undergoing MitraClip® procedure in comparison to normal-weight patients

BACKGROUND

The number of MitraClip® implantations increased significantly in recent years. Data regarding the impact of weight class on survival are sparse.

HYPOTHESIS

We hypothesized that weight class influences survival of patients treated with MitraClip® implantation.

METHODS

We investigated in-hospital, 1-year, 3-year, and long-term survival of patients successfully treated with isolated MitraClip® implantation for mitral valve regurgitation (MR) (June 2010-March 2018). Patients were categorized by weight classes, and the impact of weight classes on survival was analyzed.

RESULTS

Of 617 patients (aged 79.2 years; 47.3% females) treated with MitraClip® implantation (June 2010-March 2018), 12 patients were underweight (2.2%), 220 normal weight (40.1%), 237 overweight (43.2%), and 64 obesity class I (11.7%), 12 class II (2.2%), and 4 class III (0.7%). Preprocedural Logistic EuroScore (21.1 points [IQR 14.0-37.1]; 26.0 [18.5-38.5]; 26.0 [18.4-39.9]; 24.8 [16.8-33.8]; 33.0 [25.9-49.2]; 31.6 [13.1-47.6]; p = .291) was comparable between groups. Weight class had no impact on in-hospital death (0.0%; 4.1%; 1.5%; 0.0%; 7.7%; 0.0%; p = .189), 1-year survival (75.0%; 72.0%; 76.9%; 75.0%; 75.0%; 33.3%; p = .542), and 3-year survival (40.0%; 36.8%; 38.2%; 48.6%; 20.0%; 33.3%; p = .661). Compared to normal weight, underweight (hazard ratio [HR]: 1.35 [95% confidence interval [CI]: 0.65-2.79], p = .419), obesity-class I (HR: 0.93 [95% CI: 0.65-1.34], p = .705), class II (HR: 0.39 [95% CI: 0.12-1.24], p = .112), and class III (HR: 1.28 [95% CI: 0.32-5.21], p = .726) did not affect long-term survival. In contrast, overweight was associated with better survival (HR: 1.32 [95% CI: 1.04-1.68], p = .023).

CONCLUSION

Overweight affected the long-term survival of patients undergoing MitraClip® implantation beneficially compared to normal weight.

Heart valve surgery and the obesity paradox: A systematic review

Obesity has been associated with increased incidence of comorbidities and shorter life expectancy, and it has generally been assumed that patients with obesity should have inferior outcomes after surgery. Previous literature has often demonstrated equivalent or even improved rates of mortality after cardiac surgery when compared to their lower-weight counterparts, coined the obesity paradox. Herein, we aim to review the literature investigating the impact of obesity on surgical valve interventions. PubMed and Embase were systematically searched for articles published from 1 January 2000 to 15 October 2021. A total of 1315 articles comparing differences in outcomes between patients of varying body mass index (BMI) undergoing valve interventions were reviewed and 25 were included in this study. Patients with higher BMI demonstrated equivalent or reduced rates of postoperative myocardial infarction, stroke, reoperation rates, acute kidney injury, dialysis and bleeding. Two studies identified increased rates of deep sternal wound infection in patients with higher BMI, although the majority of studies found no significant difference in deep sternal wound infection rates. The obesity paradox has described counterintuitive outcomes predominantly in coronary artery bypass grafting and transcatheter aortic valve replacement. Recent literature has identified similar trends in other heart valve interventions. While the obesity paradox has been well characterized, its causes are yet to be identified. Further study is essential in order to identify the causes of the obesity paradox so patients of all body sizes can receive optimal care.