Factor V Leiden and morbid obesity in fatal postoperative pulmonary embolism

Hypothesis: Currently, the risk for postoperative acute pulmonary embolism (APE) is assessed clinically. We hypothesize that the expensive screening for the most common genetic thrombophilic clotting defect (factor V Leiden; R(506)Q) after exclusion of established clinical risk factors does not offer additional benefit to surgical patients. Design: We reviewed protocols and histories from 8249 consecutive autopsies performed at the Mayo Clinic, Rochester, Minn. All patients who died of APE after routine surgery and who lacked any other clinical risk factors for APE were included and compared with matched controls. Genomic DNA was extracted from archival tissues and examined for R(506)Q by polymerase chain reaction amplification, restriction enzyme digestion, and direct sequencing. Results: Acute pulmonary embolism was the immediate cause of death in 454 patients (5.5%). Of those, 32 (7.0%) had undergone routine surgery. These patients represent less than 0.07% of all case-adjusted surgical procedures in the same period. The rate of postoperative death from APE was higher after neurosurgical procedures (0.3%) than all other procedures (0.04%). Sixteen patients (50.0%) were morbidly obese. Only 1 patient was heterozygous and none were homozygous for R(506)Q. Conclusions: (1) Fatal APE is uncommon in surgical patients lacking clinically apparent risk factors for venous thromboembolism. (2) Neurosurgical patients are at increased risk for postoperative APE. (3) Morbid obesity is a major independent risk factor in cases of sudden death from APE postoperatively. (4) Routine preoperative screening for R(506)Q ill the factor V gene does not appear to offer additional benefit in surgical patients without clinically recognizable thromboembolic risk factor(s).