ORLANDO – Researchers have identified risk groups of common perioperative conditions that indicate an increased risk for venous thrombotic events during arterial reconstruction procedures in an analysis of a large administrative database.
The findings could lead to more aggressive venous thrombotic event (VTE) prophylaxis strategies for patients with those "risk families," Dr. Leila Mureebe said at the annual meeting of the American Venous Forum.
Dr. Leila Mureebe
Infectious and pulmonary risk families were more commonly associated with VTE. Urinary and intestinal risk families were associated with a lower – although still important – risk of VTEs, said Dr. Mureebe, a vascular surgeon at Duke University in Durham, N.C.
Rates of deep vein thrombosis (DVT) and pulmonary embolism (PE) after common vascular procedures are poorly defined. However, determining the true incidence and/or prevalence would be impractical, she noted.
The researchers used administrative data from the National Inpatient Sample (NIS) to identify patients at increased risk of VTE by identifying associated pre- and postoperative factors. The NIS captures discharges by procedure, and is designed to approximate a 20% sample of U.S. community hospitals. All discharges from sampled hospitals are included in the NIS database, which contains clinical and resource-use information (typically included in a discharge abstract).
This study included all discharges during 2000-2008 with primary arterial operations (abdominal aortic aneurysm [open], aortobifemoral bypass, carotid endarterectomy, and infrainguinal bypass). Procedure codes were crossed by diagnosis code for DVT and PE diagnoses. Next the researchers subselected the population that was associated with VTE, including VTE discharges.
The incidence of VTE was 0.34% of 73,545 patients undergoing abdominal aortic aneurysm repair, 0.06% of 372,465 patients undergoing carotid endarterectomy, 0.27% of 50,415 patients undergoing aortobifemoral bypass, and 0.31% of 253,234 patients undergoing bypass graft.
"We then created risk families to capture the relatively common perioperative events," said Dr. Mureebe. The risk families included intestinal (ileus, small-bowel obstruction), pulmonary (aspiration, bronchitis, pneumonia, lobar pneumonia), urinary complications (urinary tract infection not otherwise specified, indwelling urinary catheter), infectious complications (postoperative infection, postoperative abscess, intra-abdominal infection, stitch abscess, subabscess, wound complications, septicemia, infection due to vascular device, and systemic inflammatory response syndrome), and cardiac (acute myocardial infarction, acute coronary occlusion without MI).
Potential confounders included age at admission, sex, a history of DVT/PE, and a history of a coagulopathy (clotting defect, thrombocytosis, heparin-induced thrombocytopenia, antithrombin deficiency, and mutations [factor V Leiden, prothrombin gene]). Logistic regression was used to assess the association between VTE and risk families. The model was adjusted for age and sex.
In all, 755,536 weighted procedures were identified. VTEs were found in 1,445 diagnoses, for an overall prevalence of 0.19%. "Interestingly, each family of complications was associated with a different risk of VTE," said Dr. Mureebe. The risk of intestinal family complications was 0.62%. Pulmonary, urinary, and infectious family risk rates were 1.2%, 0.66%, and 1.46%, respectively. "Cardiac fell out of all analyses and was not associated – at least in this dataset – with the development of VTEs."
Confounders were more strongly associated with VTEs, Dr. Mureebe noted. A history of VTE was associated with a 2.2% increased risk, and a history of coagulopathy was associated with a 1.68% increased risk.
"So, in addition to discrete risk families having increased risk, there’s also a different profile dependent upon the actual surgical procedure."
For example, in carotid endarterectomy – which is associated with an overall low risk of VTEs – "we really see a large contribution from these potential risk families," she said.
Dr. Mureebe did not report whether she had any relevant financial disclosures.