Bariatric Surgery Tied to Better Long-term Outcomes After MI
Though based on high-quality registry data, the findings need to be confirmed in a randomized trial, the lead researcher says.
Among severely obese patients with a previous MI, bariatric surgery is associated with a lower risk of major adverse outcomes over the next several years, according to a Swedish registry study.
Patients who underwent either Roux-en-Y gastric bypass or sleeve gastrectomy had lower risks of MACE and several stand-alone cardiac endpoints through nearly 8 years of follow-up compared with MI patients who didn’t undergo bariatric surgery, researchers led by Erik Näslund, MD, PhD (Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden), report.
An encouraging finding, Näslund told TCTMD, was that postoperative complications did not occur at a higher-than-expected rate in the patients with a prior MI.
The study, published online October 26, 2020, ahead of print in Circulation, was based on high-quality registry data from Sweden, he added, but it’s still subject to limitations inherent to observational analyses.
“These data imply that if you have had a prior MI, and you’re sufficiently obese to be qualifying for bariatric surgery, or metabolic surgery as we call it, then you should undergo the surgery,” Näslund said. “It implies that, but in order to prove it then we need to do a randomized controlled trial.”
The effect of bariatric surgery in terms of primary prevention of CVD in patients with severe obesity is “relatively established,” according to the authors, who point out that there are limited data on the use of weight-loss surgery for secondary prevention of CVD.
To examine the impact of bariatric surgery in patients with a prior MI, the investigators linked data from the SWEDEHEART registry and the Scandinavian Obesity Surgery Registry. The analysis included 509 patients with prior MI who underwent Roux-en-Y gastric bypass (91%) or sleeve gastrectomy (9%) and were matched to an equal number of patients with prior MI who did not undergo weight-loss surgery. Mean age was 53, and 57% of patients were men. The average time from MI to either surgery or the start of follow-up was a little over 4-and-a-half years.
The surgical group was less likely to have an ejection fraction below 40% (7% vs 12%), previous heart failure (10% vs 19%), A-fib (6% vs 10%), and chronic obstructive pulmonary disease (4% vs 7%).
Postoperative complications within 30 days occurred in 8.4% of patients, with 3.8% having complications that were considered serious. One patient died from a CV event related to massive postoperative bleeding, for a 30-day mortality rate of 0.2%.
As expected, bariatric surgery led to a significant drop in weight, with median body mass index declining from 40 kg/m2 at baseline to 29 kg/m2 at 1 year and 28 kg/m2 at 2 years. The percentage of weight lost was 28% and 29%, respectively, at those time points. By 1 year, substantial proportions of patients also had remission of diabetes (52.3%), hypertension (24.7%), dyslipidemia (35.6%), and sleep apnea (66.1%).
Over up to 8 years of follow-up (median 4.6 years), patients who underwent bariatric surgery had significantly lower rates of MACE (18.7% vs 36.2%; adjusted HR 0.44; 95% CI 0.32-0.61), death (11.7% vs 21.4%; adjusted HR 0.45; 95% CI 0.29-0.70), MI (5.4% vs 17.9%; adjusted HR 0.24; 95% CI 0.14-0.41), and new-onset heart failure compared with the nonsurgical group (2.0% vs 4.9%; P = 0.03, with not enough events for multivariable adjustment).
There were no significant differences between the surgical and nonsurgical groups in terms of stroke (3.5% vs 5.4%; adjusted HR 0.91; 95% CI 0.38-2.20) or new-onset A-fib (8.7% vs 9.9%; adjusted HR 0.56; 95% CI 0.31-1.01).
“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 investigators say. They propose that the lower risk of MACE after surgery “is caused not only by a larger and more sustainable weight loss, but also by other cardiometabolic effects of metabolic surgery.”
Commenting for TCTMD, Nieca Goldberg, MD (NYU Langone Health, New York, NY), said this study is “a very interesting look at procedures that we do for weight loss that shows, first, that it was done safely in people with previous MI, but [it] also showed a reduction in new cardiovascular events.”
She added, “I want to caution and say that this study was a good start, but even the researchers said more studies to look at the benefits and risks of the procedure in terms of cardiovascular risk, larger studies, are needed. So right now, I think that for people who fit a category for being a candidate for bariatric surgery should see that there is improvement in cardiovascular risk factors.”
Asked whether there are any specific concerns about taking patients who have had an MI in for bariatric surgery, both Goldberg and Näslund said they would be worked up to ensure they were fit for surgery like any other patient, with Goldberg saying that physicians would check for active cardiac symptoms, level of heart function, and blood pressure control. Both pointed out that surgeons wouldn’t typically perform bariatric surgery on a patient who has had an MI within the past 6 months.
“This is not a question of taking these people immediately to the operating room,” Näslund said. “It’s a matter of waiting until their cardiac health is sufficiently good for us to operate upon them and then doing the surgery.”
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: a nationwide cohort study. Circulation. 2020;Epub ahead of print.
- The study was supported by grants from Region Örebro County and Stockholm County Council.
- Näslund reports no relevant conflicts of interest.