Gastric Bypass May Offer More Protection Against Cardiovascular Disease than Gastric Banding
Key findings
- Among 15,125 adults with obesity and prior cardiovascular disease (CVD), those who underwent gastric bypass, compared to those who had gastric banding, were significantly less likely to need acute care for CVD in the seven to 24 months after surgery
- The between-group difference persisted in a propensity-matched cohort
- The difference was primarily driven by lower rates of acute care use related to coronary artery disease and heart failure in the gastric bypass group
- During the early postoperative period, patients in the gastric bypass group were more likely than the gastric banding group to need acute care for venous thromboembolism, underscoring the need for preventive measures
Recent research reports that that gastric bypass results in not only more weight loss compared with adjustable gastric banding, but also more improvement in metabolism and cardiovascular disease (CVD) risk factors. However, no prior studies have examined whether the differences in risk factors translate into different effects on CVD outcomes.
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Kohei Hasegawa, MD, HMS, attending physician in the Department of Emergency Medicine at Massachusetts General Hospital, led the study team which included David F. M. Brown, MD, chief of the Mass General Department of Emergency Medicine, to address this knowledge gap. Dr. Hasegawa and colleagues become the first to address this knowledge gap. In Nutrition, Metabolism & Cardiovascular Diseases, they report that gastric bypass, when compared with gastric banding, may offer a higher degree of CVD protection in the long term.
Study Design
The researchers analyzed 15,125 adults from population-based hospital datasets from three racially/ethnically, socioeconomically and geographically diverse U.S. states: California, Florida and Nebraska. These adults had obesity, prior CVD and underwent either gastric bypass (n=11,229) or gastric banding (n=3,896) between 2005 and 2011.
The primary outcome measure was acute care use—emergency department visits and unplanned hospitalizations—for CVD. The secondary outcome measures were acute care use for each of the five most common CVD categories: coronary artery disease (CAD), heart failure (HF), hypertension, dysrhythmia and venous thromboembolism (VTE).
Primary Outcomes
The researchers describe the following primary outcomes for the entire cohort:
During the first six months after bariatric surgery, there was no significant difference between the gastric bypass and gastric banding groups with respect to acute care for CVD.
In contrast, patients who underwent gastric bypass had a 31% lower rate of acute care events in the seven to 12 months postoperatively (rate ratio, 0.69; 95% CI, 0.56–0.87, P = .002).
The event rate also significantly favored gastric bypass during:
- The 13 to 18 months after surgery, by 32%
- The 19 to 24 months after surgery, by 39%
- The seven to 12, 13 to 18 and 19 to 24 months after surgery, according to multivariable-adjusted analyses
According to researchers, primary outcomes specific to the second cohort were as follows:
- The researchers matched 3,745 of the patients in the gastric banding group with an equivalent number of patients who underwent gastric bypass, according to demographics, insurance type, season and year of surgery, state, hospital and Elixhauser comorbidity index
- The results in the propensity-matched cohort were consistent with the main analysis. Patients who underwent gastric bypass had significantly lower event rates of acute care for CVD during the seven to 12, 13 to 18 and 19 to 24 months after surgery when compared with those who underwent gastric banding
Secondary Outcomes
The use of acute care for specific diagnoses fell into three categories:
- Hypertension and dysrhythmia: Use of acute care did not differ between the gastric bypass and banding groups
- CAD and HF: Use of acute care was significantly lower in the gastric bypass group
- VTE: During the first six-month postoperative period, use of acute care was significantly higher for patients who underwent gastric bypass than for those who had gastric banding
Potential Mechanisms of the Differences
The nonsignificant increase in acute care events in the short term (the first six months postoperatively) may be explained, at least partially, by the significantly higher rate of VTE-related events during that period. Postoperative VTE is theoretically preventable, so this study underscores the importance of optimal VTE preventive measures and frequent VTE surveillance in patients who have recently undergone bariatric surgery, especially gastric bypass.
The lower rates of acute care use for CAD and HF associated with gastric bypass, compared with gastric banding, may be attributable to the greater weight reduction and metabolic effects of gastric bypass. These benefits lead to the reversal of some obesity-related changes that are relevant to CVD, such as left ventricular hypertrophy and diastolic dysfunction, lipotoxicity, systemic inflammation, activation of the renin-angiotensin-aldosterone system and higher sympathetic tone.
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