The effect of weight loss on the outcome after coronary artery bypass grafting in obese patients

Abstract

The role of body mass index (BMI) in the setting of coronary artery bypass graft (CABG) surgery has been a focus of past studies. However, the effects of postoperative weight loss in patients after CABG is yet to be known. We performed a retrospective study of 899 patients who underwent CABG at our institution. Perioperative patient information was collected from an onsite electronic record system. Patients were grouped into four BMI categories: normal controls, overweight, obese and morbidly obese. Based on the postoperative BMI changes, patients were then grouped into three categories: gainers, no change and losers. Statistical analyses were performed using analysis of variance and linear regression to establish an association among the data. Hazard ratios (HR) and cumulative survival were obtained by the Cox-Mantel and Kaplan-Meier analyses, respectively. The normal controls exhibited a markedly higher mortality postoperatively, at 27.9%, especially when compared with the obese individuals (16.1%). Patients who lost weight faced a significantly increased risk of mortality than those who experienced no changes or gained weight after surgery. This trend was especially salient among the obese patients, who more than tripled their mortality risk (HR = 3.24) versus individuals who gained weight, and more than doubled their risk (HR = 2.87) versus those who had no changes. We conclude that obesity confers a survival advantage in the setting of the CABG surgery. Weight loss among all BMI categories of patients studied results in an adverse effect on postoperative survival.

Secondary Prevention After Coronary Artery Bypass Graft Surgery

“…Retrospective, observational studies assessing the association between weight loss and clinical outcomes after CABG have shown paradoxical results, with worse outcomes among patients losing weight after CABG. 403 However, these studies could not differentiate between purposeful and unintentional weight loss. Unintentional weight loss could reflect comorbidities such as heart failure, cancer, and lung diseases or may reflect the severity of other conditions associated with decreased survival.…”

The importance of weight stabilization amongst those with overweight or obesity: Results from a large health care system

“…Several observational studies have shown worse outcomes with weight loss in broad populations ( Karahalios et al, 2014 , Pack et al, 2014 , Myers et al, 2011 , Østergaard et al, 2010 ) and also in specific sub-groups, including individuals with diabetes, ( Lee et al, 2020 ) patients with ischemic stroke ( Wohlfahrt et al, 2015 ) or coronary heart disease, ( Moholdt et al, 2018 ) and those who have undergone coronary artery bypass graft surgery. ( Kocz et al, 2012 ) However, most of these studies could not distinguish between unintentional and intentional weight loss. While unintentional weight loss may be due to underlying cachexic conditions that lead to increased risk of poor outcomes ( De Stefani et al, 2018 ), intentional weight loss would be expected to improve outcomes given associated improvements in glucose, blood pressure, and lipids.…”

Analysis of Outcomes of the Nutritional Status in Patients Qualified for Aortic Valve Replacement in Comparison to Healthy Elderly

“…It has been documented that preoperative unintentional weight loss results in adverse effects on postoperative outcomes [ 32 ]. Moreover, decreased body weight is also observed after cardiac surgery and may intensify problems associated with nutritional status and outcomes, even in those with a high BMI [ 33 ].…”