Improved survival after bariatric surgery in patients with previous myocardial infarction
STOCKHOLM, Sweden: Researchers at Karolinska Institutet and Danderyd Hospital have studied the risk of additional myocardial infarctions and early death in severely obese patients who underwent metabolic surgery following a myocardial event. The registry study, which included 1,018 individuals, showed a lower risk of additional myocardial infarctions and an improved survival rate that cannot be attributed solely to weight loss.
In 2016, around two billion adults, 18 years and older, were overweight. Of these over 650 million were classified as obese with a body mass index (BMI) over 30, according to the World Health Organization. Severe obesity—in this study defined as BMI above 35—increases the risk of several health problems, including Type 2 diabetes, hypertension, cardiovascular disease and cancer.
Patients who lose weight can improve their health and it has previously been shown that after metabolic surgery, diabetes and hypertension go into a period of remission in which the symptoms disappear, at least temporarily.
In the current study, researchers at Karolinska Institutet, Örebro University and Uppsala University examined the risk of additional myocardial infarction and early death in people with severe obesity and a previous infarction who subsequently underwent metabolic surgery.
By cross-referencing the quality registries Scandinavian Obesity Surgery Registry and SWEDHEART (a registry for patients who have suffered myocardial infarction) between 1995 and 2018, the researchers were able to identify severely obese individuals who underwent a gastric bypass or gastric sleeve procedure as a treatment for their obesity after suffering a myocardial infarction.
Lower risk of myocardial infarction
The group of 509 individuals who underwent surgery was matched with patients of the same gender, age and BMI, and who had suffered a myocardial infarction in the same year but not undergone metabolic surgery.
“We found that individuals operated for their obesity were at a much lower risk of suffering another myocardial infarction, of death and of developing heart failure,” said first author Erik Näslund, professor at the Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet. “These data suggest that severely obese people who suffer a myocardial infarction should be offered metabolic surgery for their obesity as a secondary prevention.”
Remission of Type 2 diabetes
According to the researchers, weight loss is unlikely to be the only reason for the link observed in the study between metabolic surgery and a lower risk of cardiopathic events like stroke, heart attack or early death. One possible explanation is that metabolic surgery per se has a positive impact on cardiometabolic risk factors.
“Many of the patients who underwent metabolic surgery in this study had clinical remission of Type 2 diabetes, hypertension and dyslipidemia. An earlier study, Look AHEAD, demonstrated that long, intensive non-surgical lifestyle intervention in patients with Type 2 diabetes resulted in weight loss of 6%, but did not lower the risk of myocardial infarction.”
More research needed
Before the study results can be incorporated into clinical practice, further research is needed. In this follow-up research, severely obese people who have suffered a myocardial infarction will need to be randomly assigned to either surgery or regular post-infarction care.
The study, titled “Association of Metabolic Surgery With Major Adverse Cardiovascular Outcomes in Patients With Previous Myocardial Infarction and Severe Obesity: A Nationwide Cohort Study”, was published on 26 October in Circulation.