Improving Cardiac Outcomes Through Bariatric Surgery

By Daniel K. Brantley
Friday, September 10, 2021
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The link between obesity and cardiovascular health is well established. Until recent years, however, it was unclear whether bariatric surgery could improve morbidity and mortality among obese individuals who had already experienced significant cardiovascular events.

Traditionally, such individuals were deemed poor candidates for surgical intervention. This view is being reconsidered due to multiple studies that have found bariatric surgery to have a significant impact on the postsurgical health of patients with previous cardiac events.

MACE: A 10-Year Retrospective Review

Researchers in Ontario sought to determine the specific effect of bariatric surgery on longevity and the risk of future MACE (major adverse cardiac events). During their retrospective study, researchers reviewed Ontario-based bariatric surgery patients from January 2010 to December 2016 and compared them to obese patients who did not undergo surgery. Though not a randomized study, this population-based, propensity score-matched study allowed researchers to approximate the conditions of a randomized study.

The researchers found that among obese individuals with a significant history of major cardiac events, bariatric surgery led to a substantial reduction in the likelihood of future events and improved mortality, even among those in need of a heart or lung transplant. Whereas previous studies found an improvement of approximately 30%, the MACE study found a reduction twice as high. The implications are clear.

“In our view, such patients — if they meet surgical criteria — should be considered for bariatric surgery,” says Mehran Anvari, MD, PhD, Professor of Surgery at McMaster University in Hamilton, Ontario.

According to Dr. Anvari, the MACE study establishes the need to have a large, multicenter, randomized, controlled study to further look at the efficacy of bariatric surgery in this population. To that end, he and his colleagues are working to secure funding and hope to begin their study soon. Physicians interested in participating should contact Dr. Anvari at anvari@mcmaster.ca.

Cutting Subsequent MI Risk in Half

An observational study in Sweden found that metabolic surgery plays a role in secondary prevention of myocardial infarction. In the study, researchers demonstrated that metabolic surgery has no significant impact on stroke or newly developed atrial fibrillation. It does, however, reduce the risk of death significantly and decreases new MI in patients with severe obesity and a personal history of MI.

“I anticipated that the surgery would have an effect, but not to the magnitude that we found,” says Erik Näslund, MD, PhD, Professor of Surgery, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet in Stockholm, Sweden.

Moving forward, Dr. Näslund laid out three steps to further validate the study’s findings.

  1. Further research to determine if there is a difference in surgical risk in patients with severe obesity and previous MI.
  2. Determine if all patients with severe obesity and previous MI benefit from weight-loss surgery or whether some patients are poor surgical candidates.
  3. Perform a randomized clinical trial.

Additionally, Dr. Näslund suspects those with Type 2 diabetes and prior MI may have the greatest benefit from bariatric surgery, as it addresses both issues. Future research will be necessary to validate this theory.

Improving CHF With Bariatrics

Within the morbidly obese population, “the risk for heart failure increases from 30% up to 100%,” says Collin E.M. Brathwaite, MD, MS, FACS, Professor and Chair of the Department of Surgery, Chief of the Division of Minimally Invasive and Bariatric Surgery at NYU Long Island School of Medicine and Director of the Metabolic and Bariatric Surgery Program at NYU Langone Hospital–Long Island.

Based on research that showed positive effects of gastric bypass and sleeve gastrectomy on obese rats with diabetes and personal experience with obese CHF patients, Dr. Brathwaite and colleagues launched research to investigate whether bariatric surgery is a safe option for obese individuals with CHF.

“Currently, bariatric surgery is only being utilized in 1% of the population who may benefit from it,” Dr. Brathwaite says. “The study suggests … bariatric surgery can be performed safely in patients with a history of CHF.”

Encouraging as this news is, the study was limited. It was retrospective in design (CHF patients who underwent bariatric surgery over 11 years were studied), and there were not hemodynamic parameters associated with CHF diagnosis made for every patient. Despite this, Dr. Brathwaite insists that morbidly obese individuals with CHF can benefit from metabolic surgery. For optimal results, he specifies, they must be prepared for surgery with optimized conditions and provided surgical intervention by an experienced team using minimally invasive techniques.

Providing a Bridge to Transplant

A novel path is being paved in bariatrics that is improving the lives of those awaiting a heart or lung transplant. Certain hospitals now use bariatric surgery in tandem with the implantation of a left ventricular assist device (LVAD) as a bridge to transplantation. Early results documented on the Thomas Jefferson University website indicate positive outcomes.

“Despite being at higher risk for heart disease, when patients with obesity develop heart failure, their road to transplant can be frustrating,” says Vakhtang Tchantchaleishvili, MD, cardiac surgeon and Assistant Professor of Surgery at Thomas Jefferson University. “Our study shows that weight reduction surgery can help patients both lose weight and qualify for heart transplant, for which they were previously not eligible due to excessive weight.”

The patients were divided into two groups. One underwent both procedures at once, and the other underwent the procedures an average of two years apart. Both groups had positive results.