NEW YORK (Reuters Health) – Aggressive reduction of cholesterol levels and normalization of high blood pressure is necessary to attenuate the progression of atherosclerotic coronary artery disease (CAD), investigators at Ohio’s Cleveland Clinic report in the Journal of the American College of Cardiology for March 31.
However, the authors of a related editorial caution that the surrogate end points used in this study may not be reliable, and that the true impact of therapy “can only be obtained from large-scale randomized clinical trials.”
For their study, Dr. Stephen J. Nicholls and fellow researchers used intravascular ultrasound (IVUS) to monitor changes in atheroma burden in 3,437 patients with CAD.
There were 263 patients with systolic blood pressure of 120 mm Hg or less and LDL-cholesterol of 70 mg/dL or less. Compared to the other patients, this group experienced less progression in percent atheroma volume and total atheroma volume and less frequent plaque progression (p < 0.001 for trends), and more frequent plaque regression (p = 0.01).
In patients with systolic blood pressure > 120 mm Hg, very low LDL-cholesterol was still associated with less progression of percent atheroma volume.
However, systolic blood pressure of 120 mm Hg or less was not enough to counter the effects of LDL-cholesterol > 70 mg/dL in promoting progression of atheroma volume, “suggesting that lower levels of LDL-cholesterol had a greater impact on progression of CAD than systolic blood pressure.”
“The results of this analysis suggest that a global risk factor modification strategy may optimize outcomes in patients with established CAD,” Dr. Nicholls and his team conclude.
Editorialists Dr. Jonathan M. Tobis and Dr. Alice Perlowski, at the David Geffen School of Medicine at UCLA in Los Angeles, point out that several sources of error can confound IVUS measurements.
“Until clinical outcomes are shown to correspond with predictions based on the IVUS surrogates,” they advise, “conclusions derived from these trials should be considered inferential, to be used as guides for future trials focused on clinical outcome measures.”
J Am Coll Cardiol 2009;53;1110-1115.