Response by Schiavon et al to Letters Regarding Article, “Effects of Bariatric Surgery in Obese Patients With Hypertension: The GATEWAY Randomized Trial (Gastric Bypass to Treat Obese Patients With Steady Hypertension)”

Circulation. 2018;138:1492–1493. DOI: 10.1161/CIRCULATIONAHA.118.036015 1492 Carlos A. Schiavon, MD, PhD Dimas Ikeoka, MD, PhD Eliana V. Santucci, Pt, BS Renato N. Santos, Stat, BS Lucas P. Damiani, Stat, MSc Alexandre B. Cavalcanti, MD, PhD Luciano F. Drager, MD, PhD On behalf of the GATEWAY Investigators In Response: We thank Moris and Guerron and Yang, Zhang, and Wang for their interest and comments on our article. The main analysis followed the modified intention-totreat principle, and all 49 patients were included in it, but Table II in the online-only Data Supplement shows 5 sensitivity analyses for the primary end point: complete case (analysis without imputation), per protocol (excluded patients from the gastric bypass group who did not undergo surgery), as treated (patients randomized to gastric bypass group who did not undergo surgery were analyzed in the medical therapy group), worst-case scenario (in case of primary end point missing it was considered positive in the medical therapy group and negative in the gastric bypass group), and multiple imputation analysis. All of them were highly significant favoring the gastric bypass.1 As described in our design paper, the technique was the same in all patients, with an alimentary limb of 150 cm and a biliopancreatic limb of 100 cm.2 We agree with Moris and Guerron that cost-effectiveness is an important issue to be studied, but this study was not primarily designed for this outcome, and longer follow-up will be certainly required for addressing this question. The mechanisms involved in the early blood pressure decrease are not entirely clear. We speculated that besides the low ingestion of sodium in the postoperative period, the reduction in insulin resistance and sympathetic hyperactivity and gut hormonal changes such as GLP1 and PYY might play an important role in the blood pressure control.3 Further studies will certainly contribute to explaining this interesting finding. The impact of bariatric surgery on cardiac function is an interesting research field. Recent evidence supports that gastric bypass surgery was associated with ≈50% of the incidence of heart failure compared with intensive lifestyle modification.4 All patients from the GATEWAY study (Gastric Bypass to Treat Obese Patients With Steady Hypertension) received a transthoracic echocardiogram at baseline and yearly in the follow-up. We are planning to have data on cardiac function up to 5 years.1 We reported some preliminary data and found that patients receiving gastric bypass presented significant (weak) lower interventricular septum diastolic thickness at 12 months compared with the patients receiving medical therapy. In the Table IV in the online-only Data Supplement, you can find the baseline and 12-month results for the septum diastolic thickness and ejection fraction in both groups.1 We also performed blood pressure optimization before study entry. Considering the baseline values of blood pressure, it is not surprising that the majority of our patients had normal echocardiogram measurements and some of them had minor alterations. Therefore, at least for this relatively short follow-up period, any conclusions about cardiac function may be interpreted with caution. © 2018 American Heart Association, Inc. RESPONSE TO LETTER TO THE EDITOR