Gastric surgery reduces blood pressure long-term

NEW YORK (Reuters Health) - Gastric surgery to treat obese patients is associated with long-term reductions in blood pressure, which are most pronounced in patients who have untreated high blood pressure before surgery.

These findings are consistent with the notion that blood pressure improves when very obese individuals lose weight after surgery, lead author Dr. John D. Fernstrom and colleagues, from the University of Pittsburgh, and colleagues note. However, additional research is needed to determine if blood pressure in these patients eventually returns to presurgical levels.

The study involved a chart review of 347 patients who underwent gastric bypass or vertical-banded gastroplasty at the researchers' institution between 1992 and 2001. The average body mass index before surgery in the two groups was 55.7 and 48.5, respectively. Individuals with a body mass index of 30 or higher are considered to be obese.

Roughly half of the patients had high blood pressure at the initial surgical evaluation, and about half of them were on blood pressure medication, according to the report in the Archives of Surgery.

After 18 months, both operative procedures were associated with a drop in body mass index that stabilized at around 35, the report indicates.

The weight loss operations were associated with a significant drop in diastolic blood pressure (the bottom number of the blood pressure reading), but had only a modest effect on systolic pressure (the top number). As noted, previously untreated patients with high blood pressure had greater declines than did treated patients or those with normal blood pressure.

Of the 103 patients treated with blood pressure drugs before surgery, 35 were able to stop these medications after surgery and maintain a normal blood pressure.

The results suggest that the overall blood pressure rates following gastric surgery for obesity substantially decline and remain low for 1.5 years after the procedure, the researchers conclude.

SOURCE: The Archives of Surgery, March 2006.