IJCS | Volume 32, Nº5, September/October 2019

531 Mourilhe-Rocha and Salvino Obesity and heart failure Int J Cardiovasc Sci. 2019;32(5):527-535 Review Article term morbid obesity. 21 Nevertheless, non-surgical weight reduction has shown that benefit in smaller studies. 6 A recent study 35 assessing high-sensitivity troponin I, a marker of subclinical myocardial injury, has suggested that weight loss following bariatric surgery may reduce cardiometabolic stress and the subsequent risk for HF. That study has assessed the impact of bariatric surgery versus lifestyle intervention, in isolation, in patients with morbid obesity. The patients submitted to bariatric surgery had a significantly higher reduction in high- sensitivity troponin I than those undergoing the intensive lifestyle intervention. 35 A clinical study, 19 assessing 23 obese class-III or class-II individuals with preoperative comorbidities six months and three years after bariatric surgery, has reported the predominance of LVH prior to surgery. Three years after, the normal pattern predominated. In addition, LV diastolic function improved in six months, remaining so for three years. 19 Another study, 36 assessing 60 women with BMI ≥ 40 kg/m 2 by using echocardiography before and six months after bariatric surgery, has concluded that the weight loss following the procedure improved ventricular diastolic function and cardiac morphology in morbidly obese women. 36 A cohort study, 37 assessing, in a 10-year follow-up, 44 Swedish obese individuals submitted to bariatric surgery and compared to two control groups (non- surgical obese patients and non-obese patients), has shown that the left ventricle adapts to long-term sustained weight loss, progressing to a smaller cavity, thinner walls and smaller ventricular mass. 37 Another study by those same authors has reported that patients with sustained weight loss have superior LV systolic and diastolic functions as compared to their obese counterparts remaining weight stable. 38 A recent study 2 based on the Swedish National Patient Registry has assessed 47,859 patients with the primary diagnosis of obesity from 2000 to 2011, and compared those submitted to bariatric surgery (n = 22,295; 46.6%) to those not submitted to surgery (n = 25,564; 53.4%). The result has shown an almost five-fold increased incidence of HF in non-surgical obese patients as compared to the obese patients submitted to bariatric surgery. This suggests that bariatric surgery can prevent HF in severely obese patients. 2 Similarly, another study 13 has assessed the efficacy of gastric bypass versus intensive lifestyle treatment to prevent HF in obese individuals from two large registries, evaluating almost 40,000 patients: 25,804 treated with gastric bypass and 13,701 submitted to lifestyle change. The first group lost more weight than the second one, and, in a mean follow-up of 4.1 years, had a lower incidence of HF. In addition, an inverse relationship between weight loss and HF incidence was observed. 13 Bariatric surgery in heart failure: safety and benefits Bariatric surgery has been safely performed in obese patients with HF and optimized pharmacological treatment. Patients with manifest systolic HF and severe obesity improved their ejection fraction and functional capacity after bariatric surgery. 1,12,34 There are several techniques of bariatric surgery: restrictive techniques, such as adjustable gastric band and vertical gastrectomy; and mixed techniques, with restrictive and disabsorptive components, such as gastric bypass. The latter has been the most frequently used in most publications analyzed in this review. The laparoscopic access has been shown to be a safe alternative for high-risk patients. 39 More than half of the patients submitted to bariatric surgery, mainly gastric bypass, lose at least 50% of excessive weight. 5 A case-control study 4 conducted in three North-American states has assessed the rate of emergency unit visits or hospitalization due to HF worsening for four consecutive years, two years before and two years after bariatric surgery, in a sample of 534 patients with HF. That study has concluded that bariatric surgery is associated with a decline in the rate of HF worsening that requires emergency unit assessment or hospitalization. The study has not identified the subtypes of HF. 4,40 Recently, Vest et al., 1 have compared 42 obese patients with LV systolic dysfunction (ejection fraction < 50%), who had undergone bariatric surgery, with 2,588 obese patients without known ventricular systolic dysfunction submitted to the same procedure. The first group showed a higher baseline prevalence of comorbidities and a mild increase in HF and infarction in the early postoperative period, but no increase in 1-year mortality. In addition, the analysis of a subgroup of 38 patients with HF, who underwent preoperative and postoperative echocardiography, has evidenced ejection fraction improvement, showing the safety and benefit of that procedure in those patients. 1,10