The Impact of Occult Malignancy on Lower Extremity Bypass Graft Thrombosis.

Abstract

OBJECTIVE\nThe presence of cancer increases arterial thromboembolic events, specifically MI and stroke, prior to a formal diagnosis of cancer. This increase in thrombotic risk has never been studied in patients with lower extremity bypass grafts. This study aimed to determine the impact of occult cancer on femoral-popliteal bypass patency.\n\n\nMETHODS\nA retrospective review of femoral-popliteal bypass procedures completed from 2001 to 2018 was performed. ICD9 and 10 codes corresponding to breast, lung, prostate, colorectal, skin, brain and hematological cancers were utilized to identify patients who had occult cancer defined as cancer diagnosed up to one year after the bypass procedure. Demographics, comorbidities, bypass configuration and conduit, 1-month, 3-month, 6-month and 1-year occlusion, major adverse limb events, and mortality rates were analyzed. Statistical analysis included t-tests, chi square tests and cox regressions.\n\n\nRESULTS\n621 procedures in 517 patients met inclusion criteria of which 36 (5.8%) had occult cancer at time of their index bypass procedure. Occult cancer patients had higher occlusion rates at 3 months (27.8% vs. 8.0%, P<0.001), 6 months (30.5% vs. 15.1%, P<0.01) and 1 year (44.4% vs. 19.8%, P<0.001). In the Cox regression for bypass thrombosis at 1-year, the only significant predictors were occult cancer (HR: 2.03, P=0.01), below-knee distal target (HR: 1.88, P<0.01) and a compromised conduit (HR: 2.14, P<0.001).\n\n\nCONCLUSION\nThere is an increase in bypass graft thrombosis rates in patients with femoral-popliteal bypasses who have occult cancer. Thrombosis of the graft within 1 year postoperatively may be a sign of occult cancer.