One of the most popular surgical procedures for treating obesity, Roux-en-Y gastric bypass (RYGB), reduces by almost half the risk of developing severe cardiovascular diseases, in patients assessed eight years following the operation.

RYGB alters the process of digestion by reducing the size of the stomach and bypassing the upper portion of the small intestine. As a result of the procedure, people feel full more quickly, while a smaller amount of food is absorbed. Surgery is indicated for people whose body mass index (BMI) — an estimate of corpulence calculated as body weight divided by square of the height — is greater than 40 kg/m2, or whose BMI is between 35 and 40 but have another condition, such as type II diabetes, hypertension, hyperlipidaemia or sleep apnoea. Beyond the positive effects on body weight, a long-term study by the Geisinger Obesity Institute in the US found the procedure brings other health benefits.

The team analysed data on more than 1,700 people who underwent RYGB between 2002 and 2012. At the time, they did not have pre-existing cardiovascular conditions. This group was compared with a control group of obese individuals who did not undergo the procedure. Follow-up data collected up to 12 years after surgery was also analysed. The team made sure that individuals in the study and control groups could be matched with each other for age, BMI, sex, ten-year cardiovascular risk, smoking history, hypertension medication and diabetes. This approach ensured that the surgery was the only factor attributable for the results.

The researchers concluded that RYGB provides long-term protection against major cardiovascular diseases, and in particular on congestive heart failure, a condition where the heart is unable to pump blood efficiently. While previous studies have linked weight loss surgery to reduction of heart attack, this is the first analysis to show the impact of RYGB on congestive heart failure.

Based on data analyses of a subset of almost 900 patients, the researchers suggest that the cardiovascular protective effects of RYGB may be the result of reductions in blood pressure, increases in HDL (good) cholesterol levels, and recovery of blood vessel elasticity. The same subset also demonstrated a significant increase in diabetes remissions.

The next challenge for the team will be to explain these improvements at the molecular level.

“In the US, there are approximately 15 million adults who are extremely obese, but less then 1% undergoes weight loss surgery. I hope that suitable patients who are at risk of cardiovascular diseases and meet the eligibility criteria would be offered this type of treatment,” says Peter N. Benotti, first author of the study.

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