Gastric bypass surgery not only helps obese people lose weight, but it may also help patients’ hearts return to a healthier state and shape, according to a new study in the Feb. 8 issue of the Journal of the American College of Cardiology.
Researchers followed more than 400 morbidly obese people who underwent the surgery and 300 obese people who did not. Those who underwent gastric bypass had an average BMI of 48 at the time of surgery (over 40 is considered morbidly obese). Within two years of surgery, the patients had lost an average of 100 pounds and managed to get their BMI down to an average 32 (over 30 is still considered obese).
The surgery recipients also had smaller waists, reduced blood pressure, lower cholesterol levels and less insulin resistance, a sign of prediabetes. Researchers found another key benefit: following surgery, the shape and function of patients’ hearts measurably improved. (More on TIME.com: Why Are More White Girls Getting Weight-Loss Surgery?)
“We know obese people get cardiovascular disease more often than non-obese people,” Dr. Sheldon Litwin, chief of cardiology at the Medical College of Georgia and the study’s lead author, told HealthDay. “One of the questions out there is: Is it reversible if they lose weight? The answer is yes.”
The connection between obesity and cardiovascular disease isn’t fully understood, but obese people often show signs of structural changes to the heart, including excess heart muscle mass in the left ventricle and enlargement of the right ventricular cavity. Both are linked to heart failure and other problems.
After surgery, however, echocardiograms of the patients’ hearts showed structural “remodeling,” including reductions in the left ventricular muscle mass and in the right ventricular cavity area. The changes suggest that the heart is less stressed and isn’t working as hard to pump blood, HealthDay reports. (More on TIME.com: What’s The BMI For Longevity?)
Although bariatric surgery can lead to profound weight loss and significant improvements in associated illnesses such as diabetes, heart disease, sleep apnea and others, it is still a relatively uncommon procedure. The surgery, like all surgeries, may carry serious risks; it is also expensive, costing $14,000 to $26,000, and isn’t always covered by insurance. Each year, about 220,000 Americans — or about 0.25% of obese Americans — undergo weight loss surgery of some kind.
For some, successful surgery can be a lifesaver. A separate study released from the University of Padova in Italy last week found that undergoing either gastric bypass or banding surgery reduced a patient’s risk of death by almost half during a 7-to-8-year period. (More on TIME.com: Post-Superbowl Heartbreak: Cardiac Death Risk May Rise For Losing Fans)
Litwin told HealthDay that his next step will be to follow surgery recipients over a longer time period to determine the long-term heart effects of gastric bypass.