Key result
Roux-en-Y gastric bypass fails to significantly alter 24-hour urinary sodium excretion postoperatively.
Why the study?
Although metabolic and bariatric surgery effectively achieves hypertension remission, it is unclear whether early metabolic changes within the first 48h after Roux-en-Y gastric bypass explain the underlying weight-loss-independent mechanisms of blood pressure control.
Does primary Roux-en-Y gastric bypass surgery alter 24-hour urinary sodium excretion or blood pressure within 48 hours postoperatively in patients with severe obesity?
Observational (n=20)
Does primary Roux-en-Y gastric bypass surgery alter 24-hour urinary sodium excretion or blood pressure within 48 hours postoperatively in patients with severe obesity?
Roux-en-Y gastric bypass does not significantly alter 24-hour urinary sodium excretion or blood pressure within the first 48 hours after surgery, suggesting that hyperacute natriuresis may not explain early postoperative blood pressure changes in normotensive or well-controlled hypertensive patients.
Loading...
No early change in urinary sodium excretion after RYGB; leaves open alternative mechanisms of hypertension remission.
Introduction Metabolic and bariatric surgery is effective in achieving remission of hypertension and metabolic disease. It is unclear whether metabolic changes within the first 48h after surgery can potentially explain underlying mechanisms of hypertension control. We aimed to assess changes in urinary sodium excretion early after Roux-en-Y gastric bypass (RYGB) as a potential weight-loss-independent mechanism of hypertension remission. Methods All patients undergoing primary RYGB provided a 24-h urine collection, blood pressure (BP) measurement, and blood sampling both preoperatively and 48h postoperatively. The dietary sodium content was similar at both time points. Results Twenty patients were included, of whom 16 met the minimum output urine volume criteria for 24-h urine samples. Mean patient age was 55.2 ± 7.7 years and median body mass index was 48kg/m 2 with 13 patients (65%) diagnosed with hypertension and 7 (35%) with obstructive sleep apnoea. Twenty-four-hour urine sodium excretion was similar immediately prior to surgery and 48h postoperatively (72.1 ± 44.0 vs 74.5 ± 65.2mmol/24h, p = 0.45). There was no significant difference in systolic or diastolic BP immediately prior to surgery compared with 48h postoperatively (143.3 ± 15.1 vs 135.9 ± 16.3mmHg, p = 0.09 and 79.8 ± 9.2 vs 79.9 ± 5.8mmHg, p = 0.47). Both findings were confirmed on further sensitivity analysis. Conclusion No significant change in urinary sodium excretion or BP was detected in the first 48h post RYGB in normotensive patients or those with well-controlled hypertension.
Henry et al. (2026) conducted an observational in Severe obesity and hypertension undergoing Roux-en-Y gastric bypass (n=20). Roux-en-Y gastric bypass (RYGB) vs. Preoperative baseline was evaluated on 24-hour urinary sodium excretion (p=0.45). Roux-en-Y gastric bypass resulted in no significant change in 24-hour urinary sodium excretion at 48 hours postoperatively compared to baseline (74.5 vs 72.1 mmol/24h, p=0.45).