By Crina Frincu-Mallos, PhD
NEW YORK, NY -- October 7, 2007 -- Intravascular ultrasound (IVUS) is a powerful research tool in precisely assessing atherosclerotic disease progression, with impact on the development of novel anti-atherosclerotic therapies, researchers reported here at the XVI International Symposium on Drugs Affecting Lipid Metabolism (DALM).
Steven E. Nissen, MD, MACC, Chairman, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio, United States, and Immediate Past President, American College of Cardiology, Washington, DC, discussed the application of IVUS in recent clinical trials, in a plenary general session on October 6.
The application of this technique to the study of atherosclerosis progression or regression was examined in a few recent clinical studies, the REVERSAL (Reversal of Atherosclerosis with Aggressive Lipid Lowering) trial being one example, said Dr. Nissen. The rate of atheroma progression, as a percentage volume change, was compared over 18-months treatment with pravastatin versus atorvastatin.
The final mean LDL-C levels were 78.9 mg/dL in the atorvastatin 40 mg patients, compared to 110.4 mg/dL the group treated with pravastatin 80 mg. In addition, the decrease in the C-reactive protein (CRP) levels was significantly larger in the atorvastatin-treated patients (-36.4% vs -5.2%, P <.001).
Furthermore, IVUS clearly showed that the atheroma volume remained basically "unchanged over 18 months in patients treated with atorvastatin 80 mg (-0.4% total volume change), whereas patients on pravastatin 40 mg experienced a 2.7% increase in the total atheroma volume (P =.02)", explained Dr. Nissen.
IVUS was employed as well in the recent ILLUSTRATE trial to assess the potential benefit of adding an inhibitor of cholesterol ester transfer protein (CETP) to standard therapy, said Dr. Nissen.
A total of 1,190 patients were randomised to receive atorvastatin or the combination of atorvastatin and torcetrapib, a CETP inhibitor. Interestingly, commented Dr. Nissen, "the use of the combination resulted in a 60% increase in HDL-C and 20% decrease in LDL-C" compared to atorvastatin alone, yet IVUS showed no decrease in the atheroma volume attributable to torcetrapib.
Regression of atheroma with statin therapy was observed using IVUS in the ASTEROID trial, which enrolled 349 patients with coronary disease. After 24-months treatment with rosuvastatin 40 mg daily, the patients experienced an approximately 50% reduction in mean values for LDL-C, from 130.4 mg/dL to 60.8 mg/dL, and a 14.7% increase in HDL-C. In the most diseased, 10 mm segment, of the patient population, IVUS showed a -5.6% change in the total atheroma volume when compared to baseline.
Using IVUS, it was possible to show that intensive statin therapy to get LDL-C levels below current guidelines, together with an increase in HDL-C, could lead to the regression of atherosclerosis in patients with coronary disease, concluded Dr. Nissen.
[Presentation title: Recent Clinical Trials - Lessons learned from Intravascular Ultrasound. Plenary General Session 9]
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