Inhibition of renin angiotensin axis may be associated with reduced risk of developing venous thromboembolism in patients with atherosclerotic disease.

BACKGROUND: Arterial and venous thrombosis may share common pathophysiology involving the activation of platelets and inflammatory mediators. A growing body of evidence suggests prothrombotic effect of renin angiotensin system (RAS) including vascular inflammation and platelet activation. We hypothesized that the use of angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) plays a role in protecting against venous thromboembolism (VTE) in patients atherosclerosis. METHODS: We conducted a retrospective study, reviewing 1,100 consecutive patients admitted to a teaching hospital with a diagnosis of either myocardial infarction or ischemic stroke from 2005 to 2010. Patients who had been treated with anticoagulation therapy before or after the first visit were excluded. The occurrence of VTE during the follow up period, risk factors for VTE on admission, and the use of ACEIs or ARBs during the follow up period were recorded. RESULTS: The mean age of the entire study population was 68.1 years. 52.0% of the patients were female and 76.5% were African American. 67.3% were on RAS inhibitors. The overall incidence of VTE was 9.7% (n = 107). Among the RAS inhibitor users, the incidence of VTE events was 9.0% (54/603) for the ACEI only users, 7.1% (8/113) for the ARB only users, and 0% (0/24) for the patients taking combination of ACEI and ARB. Among patients on RAS inhibitors, 8.4% (62/740) developed a VTE, compared with 12.5% (45/360) in the nonuser group [HR (hazard ratio), 0.58; 95% CI (confidence interval), 0.39-0.84; P<0.01]. Even after controlling for factors related to VTE (smoking, history of cancer, and immobilization, hormone use) and diabetes, the use of RAS inhibitors was still associated with a significantly lower risk of developing VTE (AHR, 0.59; 95% CI, 0.40-0.88; P = 0.01). CONCLUSIONS: The use of RAS inhibitors appears to be associated with a reduction in the risk of VTE.

Dose-related effect of statins in venous thrombosis risk reduction.

BACKGROUND: Atherosclerosis and venous thromboembolism share similar pathophysiology based on common inflammatory mediators. The dose-related effect of statin therapy in venous thromboembolism remains controversial. This study investigated whether the use of antiplatelet therapy and statins decrease the occurrence of venous thromboembolism in patients with atherosclerosis. METHODS: We conducted a retrospective cohort study reviewing 1795 consecutive patients with atherosclerosis admitted to a teaching hospital between 2005 and 2010. Patients who had been treated with anticoagulation therapy were excluded. Patients who either used statins for <2 months or never used them were allocated to the nonuser group. RESULTS: The final analysis included 1100 patients. The overall incidence of venous thromboembolism was 9.7%. Among statin users, 6.3% (54/861) developed venous thromboembolism, compared with 22.2% (53/239) in the nonuser group (hazard ratio [HR] 0.24; P <.001). After controlling for confounding factors, statin use was still associated with a lower risk of developing venous thromboembolism (HR 0.29; P <.001). High-dose statin use (average 50.9 mg/day) (HR 0.25; P <.001) lowered the risk of venous thromboembolism compared with standard-dose statins (average 22.2 mg/day) (HR 0.38; P <.001). Dual antiplatelet therapy with aspirin and clopidogrel decreased occurrence of venous thromboembolism (HR 0.19; P <.001). Interestingly, combined statins and antiplatelet therapy further reduced the occurrence of venous thromboembolism (HR 0.16; P <.001). CONCLUSIONS: The use of statins and antiplatelet therapy is associated with a significant reduction in the occurrence of venous thromboembolism with a dose-related response of statins.