Bariatric Surgery Patients Fare Better After Heart Attacks and Strokes

Bariatric surgery has proven to confer significant protective effects on patients who, after the weight loss operations, wind up having either a heart attack or a stroke, a new Cleveland Clinic study shows. These patients’ chances for in-hospital survival improve, and their hospital length-of-stay after the event diminishes.

The fact that weight-loss surgery leads to striking reductions in patients’ risk factors for heart disease, as well as helping them to avoid other weight-related risks such as those linked to diabetes, was well established by prior studies. And a decrease in mortality, especially from cardiovascular causes, for patients who had had weight loss operations had also emerged as a clear finding in earlier research. “But despite these mortality benefits, we still have bariatric surgery patients who do go on to have heart attacks and strokes. What has remained unknown is the protective benefits of the weight loss surgery on survival for these patients,” says Cleveland Clinic bariatric surgeon Ali Aminian, MD, who presented the findings recently at the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO).

The study is “the first analysis of the protective effects of bariatric surgery when future adverse events do occur,” the authors wrote.

Large data set used, and two control groups

The researchers drew upon 2007 to 2014 data from the National Inpatient Sample (NIS). The NIS is the largest publicly available all-payer inpatient care database in the United States. Each year it gathers data that describe more than 7 million hospital stays. The NIS collects data from all states that participate in the federal Healthcare Cost and Utilization Project, a large majority of states.

The research team identified 2,218 patients who had previously had bariatric surgery and whose primary discharge diagnosis was acute myocardial infarction (MI). They also identified 2,168 patients who had had bariatric surgery whose primary discharge diagnosis was ischemic cerebrovascular accident (CVA).

For control groups, the patients described above were matched (with a 1:5 ratio) with others who had similar primary discharge diagnoses but who had not undergone bariatric surgery. The researchers used two control groups. Control group #1 comprised patients with obesity only. Control group #2 comprised patients whose weights were matched to the weights of the patients who had had the weight-loss procedures.

Key results included the following:

• Mortality rates after MI were significantly lower in patients with a history of bariatric surgery, compared with control group #1 (1.85% vs. 3.03%) and with control group #2 (2.00% vs. 3.26%).
• Mortality rates after stroke were also significantly lower in patients who had undergone weight-loss surgery compared with control group #1 (1.43% vs. 2.74%) and also with control group #2 (1.54% vs. 2.59%).
• Length-of-stay was significantly reduced in the group of patients with prior bariatric surgery for all comparisons.

Limitations

In this study, the outcome of concern was limited to in-hospital mortality due to the nature of the NIS. “The database could not provide data on morbidity, readmission, and mortality after hospital discharge,” the researchers wrote.

Hoped for effects of the findings

“We do these surgeries to improve the metabolic status of the patients; to decrease mortality and improve the patients’ quality-of-life.” says Dr. Aminian.

“Our findings are in line with the other studies. This shows that even if the patient has heart attack or a stroke, the patient who has had bariatric surgery before that event will survive better,” he says, “Hopefully patients and primary care providers and even surgeons will get the message,” he says and recommend bariatric surgery for suitable candidates.

Next questions

Looking forward, Dr. Aminian and his team want to explore the fundamental reasons that bariatric surgery protects patients who experience heart attacks or strokes. “We see that patients die less if they have had the bariatric surgery previously,” he says. “But we don’t exactly know about the underlying mechanics yet, about how the procedure can confer these effects.”