VTE Risk Low in Laparoscopic Gastric Bypass

PALM BEACH, FLA. — Pharmacologic prophylaxis against venous thromboembolism is not mandatory for average-risk patients undergoing laparoscopic Roux-en-Y gastric bypass, according to data on more than 900 procedures.

“Pneumatic compression devices, early ambulation, and a relatively short operative time are effective prophylaxes against VTE,” Dr. Ronald H. Clements said.

As a follow-up to their earlier report of one deep vein thrombosis (DVT) among 380 patients (Surg. Endosc. 2004;18:1082–4), Dr. Clements and his associates continued to collect data on 957 consecutive laparoscopic Roux-en-Y gastric bypasses performed at the University of Alabama at Birmingham since 2000. Dr. Clements, a laparoscopic surgeon, presented the findings at the annual meeting of the Southern Surgical Association.

The study cohort was 83% women and 80% white. Mean age was 41 years, mean body mass index was 49 kg/m

The researchers followed all but one patient for 30 days. Among the 956 patients, there were three DVTs, one nonfatal pulmonary thromboembolism, and seven instances of major bleeding. Two patients with bleeding required reoperation, four had transfusions, and one required no intervention. One patient died of causes unrelated to DVT.

Venous thromboembolism (VTE) is a leading cause of postoperative mortality following bariatric surgery, but is “very rare: 3–7 [in] every 1,000 patients,” said study discussant Dr. Hiram C. Polk Jr., citing an unpublished study of 966,000 patients within his hospital consortium database. Elastic stockings were the most common intervention in his study. “The dangers of prophylaxis outweigh the risks of what you are trying to prevent,” said Dr. Polk, professor of surgery at the University of Louisville (Ky.).

The study “is important for the bariatric surgeon who chooses to use compression and early ambulation alone. You don't have to always use heparin,” said Dr. Bruce D. Schirmer, a general surgeon at the University of Virginia, Charlottesville, who was another study discussant. Chemoprophylaxis is still warranted for high-risk patients, he added.

But Dr. Spence M. Taylor, chair of surgery at the University of South Carolina, Greenville, took a different view. “I'm aware of at least six consensus statements for prophylaxis for DVT, and without fail, they all say chemoprophylaxis is the treatment of choice.”

Dr. Clements replied: “I don't think these obese patients fall into all those guidelines. I don't think most of you would use prophylaxis for the morbidly obese [patient undergoing] removal of a gallbladder, so I don't think you should do it for bypass, either.”

The consensus statements overlook or include only level II evidence for gastric bypass, he said, reiterating that his findings do not apply to the highest-risk patients. “I'm talking about the average person who comes to me for gastric bypass who is not at high risk” for VTE.

Citing the low incidence (0.1%–0.8%) of pulmonary embolism in this study, Dr. Taylor said, “It's conceivable you don't have enough patients yet.” Dr. Clements responded, “It's a low incidence, and that is the point of the paper. We are not saying compression devices are superior, simply that they are equivalent.”

Good follow-up and applicability of the findings to most patients undergoing gastric bypass are strengths of the study, Dr. Clements said. Limitations include the retrospective design and detection of VTE as clinically evident disease only.

“The biggest problem with your manuscript is physical examination for DVT,” Dr. Taylor said. “Don't some patients get swollen legs after surgery [even without VTE]? Don't some get shortness of breath?” Still, “from an objective standpoint, 106 minutes for bariatric procedures is an accomplishment.”