Role of Statin Therapy and Angiotensin Blockade in Patients With Asymptomatic Moderate Carotid Artery Stenosis

Background: The purpose of this study was to evaluate the 10-year outcome of patients presenting with asymptomatic moderate carotid artery stenosis, and to determine which factors correlate with progression of disease to stroke or revascularization. Methods: A retrospective review of all new patients presenting with asymptomatic moderate carotid artery stenosis from July 1998 to December 2001 was undertaken. Patients were consecutively identified and included by using duplex ultrasonography to identify moderate carotid disease. Variables were recorded for all patient encounters through June 2010. The primary end point was occurrence of ipsilateral cerebrovascular stroke or revascularization event (SORE). Statin therapy and angiotensin blockade (STAB) were categorized as follows: STAB(0)-medical treatment with neither statin therapy nor angiotensin blockade, STAB(1)-treatment with only one of the two, STAB(2)-treatment with both. An amortized cost model analyzed the cost of SORE-free survival. Results: Over a 42-month period, 468 carotids in 366 patients with an average age of 69.0 +/- 8.7 years were evaluated. Over a mean follow-up of 6.6 +/- 2.7 years, SORE occurred in 150 (32.1%) carotid arteries. Hyperlipidemia was predictive of SORE (hazard ratio [HR]: 1.543, 95% confidence interval [CI]: 1.053-2.262, P = 0.03). Medical therapies protective against SORE were beta-blockade (HR: 0.612, 95% CI: 0.435-0.861, P < 0.05), STAB(1) (HR: 0.487, 95% CI: 0.336-0.706, P < 0.01), and STAB(2) (HR: 0.149, 95% CI: 0.089-0.248, P < 0.01). At 10 years, SORE-free survival in STAB(2) was 82.7% +/- 4.6%, STAB(1) was 56.3% +/- 5.0%, and STAB(0) was 29.3% +/- 5.4% (P < 0.01). The cost per SORE-free year in STAB(2) was $1,695.40 +/- $275.60, STAB(1) was $3,916.80 +/- $605.44, and STAB(0) was $4,126.40 +/- $427.23 (P < 0.01). Conclusion: These data demonstrate the clinical and financial advantage of using both statin therapy and angiotensin pathway blockage in patients with asymptomatic moderate carotid artery stenosis.