Weight Reduction Surgery Associated With Reduced Risk of Second Heart Attack in Obese Patients

In severely obese patients with previous myocardial infarction (MI), metabolic surgery (Roux-en-Y gastric bypass or sleeve gastrectomy) was associated with a lower risk of heart attack and new onset heart failure, according to study results published in Circulation.

Not only are obese individuals nearly 6 times more likely to develop type 2 diabetes (T2D), severe obesity now puts those with coronavirus disease 2019 (COVID-19) at a high risk of death. “With the increasing prevalence of obesity there is an expected increase in obese patients with T2D and cardiovascular disease (CVD),” the authors wrote.

Using large, well-established Swedish nationwide registries, the researchers investigated the association between metabolic surgery and major adverse cardiovascular events (MACE) in patients with MI and obesity (body mass index [BMI] >35).

A total of 509 patients who had undergone metabolic surgery between 2007 and 2018 after MI were included in the observational matched cohort study. Data were gleaned from the Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies, or SWEDEHEART, registry and the nationwide Scandinavian Obesity Surgery Registry. Participants were matched 1:1 based on sex, age, year of MI, and BMI to a control with MI from SWEDEHEART who did not undergo metabolic surgery.

Four hundred and sixty-five patients underwent Roux-en-Y gastric bypass while 44 had sleeve gastrectomy. Median (interquartile range [IQR]) follow-up time was 4.6 (2.7-7.1). Analyses revealed no significant differences regarding stroke (0.91 [0.38-2.20]) or new-onset atrial fibrillation (0.56 [0.31-1.01]) between the 2 groups.

However, the researchers found:

• The 8-year cumulative probability of MACE was lower in patients undergoing metabolic surgery: 18.7% (95% CI, 15.9-21.5%) vs 36.2% (95% CI, 33.2-39.3%) (adjusted HR, 0.44; 95% CI, 0.32-0.61)
• Patients undergoing metabolic surgery had also a lower risk of death (adjusted HR, 0.45; 95% CI, 0.29-0.70; MI: adjusted HR, 0.24; 95% CI, 0.14-0.41) and new onset heart failure
• Surgery patients exhibited significant improvements in sleep apnea (67% remission), hypertension (22% remission), and cholesterol and triglyceride levels (29% remission)
• Over half of patients with T2D experienced clinical remission of the disease following the surgery

“Compared with controls matched for age, sex, BMI, and year of MI, patients undergoing metabolic surgery had less than half the long-term risk of the composite of all-cause death, MI, or stroke, all-cause death alone, and MI alone,” the authors wrote.

Metabolic surgeries are rarely used in patients after they've had an MI due to concerns the beneficial effects will not outweigh the risks of perioperative complications and long-term adverse effects. In the current study, the rate of serious complications post surgery was similar to that in patients without previous MI.

“Overall, our data indicate that metabolic surgery may be an important secondary prevention strategy in the growing population of severely obese individuals with established coronary artery disease.” The results also suggest the benefit of metabolic surgery on MACE is not caused by a greater weight loss alone, but also by cardiometabolic effects of the surgery.

Lack of data on socioeconomic status and the observational nature of the study mark limitations, and the findings ought to be confirmed in a randomized, controlled trial.

Reference:

Näslund E, Stenberg E, Hofmann R, et al. Association of metabolic surgery with major adverse cardiovascular outcomes in patients with previous myocardial infarction and severe obesity. Circulation. Published online October 26, 2020. doi:10.1161/CIRCULATIONAHA.120.048585