Pulmonary Embolism Risk May Be Elevated for Months After Surgery

By Marilynn Larkin

October 16, 2019

NEW YORK (Reuters Health) - The postoperative risk of pulmonary embolism may be elevated for at least three months after all types of surgery, a retrospective case-crossover study suggests.

Dr. Alexandre Caron of the University of Lille analyzed the risks of pulmonary embolism using data from a French database on 60,703 inpatients admitted for postoperative pulmonary embolism between 2007 and 2014. Surgical procedures were vascular, gynecologic, gastrointestinal, and orthopedic, including hip or knee replacement, fracture repairs, and other orthopedic operations.

As reported online October 9 in JAMA Surgery, the mean age was 56.6; 58.9% were male and all were cancer-free with no history of pulmonary embolism.

For all types of surgery, the risk of postoperative pulmonary embolism was highest in the immediate postoperative period (one to six weeks) and was elevated for at least 12 weeks.

Specifically, odds ratios ranged from 5.24 for vascular surgery to 8.34 for surgery for fractures. The excess risk between seven to 12 weeks ranged from OR, 2.26 for gastrointestinal operations to 4.23 for fracture surgery.

However, the risk was not clinically significant beyond 18 weeks for any type of procedure.

Summing up, the authors state, "The risk of postoperative pulmonary embolism is elevated beyond 6 weeks postsurgery regardless of the type of procedure. The persistence of this excess risk suggests that further randomized clinical trials are required to evaluate whether the duration of postoperative prophylactic anticoagulation should be extended."

Dr. Elliott Haut of Johns Hopkins University School of Medicine in Baltimore, coauthor of a related editorial, told Reuters Health by email, "As clinicians, it is very hard to know what to do with a paper like this. We have been conditioned for years to give blood clot prevention to hospitalized patients based on strong data from numerous studies, and we have gotten very good at that."

"This single paper is a dramatic change in the potential scope of who we should consider prophylaxis for," he said. "Based on these data, it seems as though we need to start examining our practice and the potential benefit of venous thromboembolism prophylaxis to a much wider range of patients."

"It will not change my practice yet," he said. "But I will certainly be looking forward to new considerations and new research on this important topic."

Dr. Philip Green, an interventional cardiologist at NewYork-Presbyterian and Columbia University Medical Center, commented by email, "This is a very important study that has the potential to change practice."

"The findings are entirely consistent with our clinical experience, as we often see patients more than 5-6 weeks after surgery who developed severe venous thromboembolic complication," he told Reuters Health.

"This study's strongest attribute is that it analyses a national database of over 203 million inpatient stays," he noted. "This allows for a robust statistical analysis."

"However, among those inpatient stays, slightly over 500,000 were for pulmonary embolism, and slightly less than 61,000 hospitalizations were used for the primary analysis in this case crossover study," he said. "Therefore, the final study sample was approximately 12% of all pulmonary embolism hospitalizations, perhaps limiting the generalizability of these findings."

"Given the retrospective nature of this analysis, (it) is quite provocative; however, it remains hypothesis-generating," he said. "Before extending routine venous thromboembolism prophylaxis beyond 4-6 weeks, I would like to see a randomized clinical trial demonstrating the clear benefit of pharmacologic prophylaxis out to 12 weeks after surgery."

"At this point, I would reserve pharmacologic prophylaxis after 6 weeks to those at the highest risk for a venous thromboembolic complication with the understanding that we are doing so based on hypothesis-generating preliminary clinical evidence," he concluded.

Dr. Caron did not respond to requests for a comment.

SOURCE: http://bit.ly/35zYDPC and http://bit.ly/2q9NTah

JAMA Surg 2019.