Letter by Kaneda Regarding Article, “Effect of Rosuvastatin Therapy on Coronary Artery Stenoses Assessed by Quantitative Coronary Angiography: A Study to Evaluate the Effect of Rosuvastatin on Intravascular Ultrasound–Derived Coronary Atheroma Burden”
To the Editor:
With great interest I read the article by Ballantyne et al examining whether rosuvastatin could regress coronary atherosclerosis by quantitative coronary angiography (QCA).1 First, the authors excluded 50 patients with adverse events and reported that 4 patients died and 10 patients (5 of whom had QCA analysis) suffered from myocardial infarction. Because these patients were likely to have progression of coronary stenoses, it would be of great help if the authors would provide additional results imputing noncompleters, as was done in the previous intravascular ultrasound (IVUS) study.2
Second, as the authors blinded baseline and follow-up images, lesions with >25% stenosis either at baseline or follow-up were assumed to be measured. However, the authors included only lesions with >25% stenosis at baseline. Exclusion of the lesions with <25% at baseline but >25% at follow-up may lead to underestimation of disease progression. In addition, the authors stated that “another limitation is the dropout rate of 25%; however, this rate is comparable to the dropout rate in similar populations in recent IVUS studies… and in prior QCA studies.” However, only 292 patients out of 507 (58%) receiving at least 1 dose of study drug were included in this study.
Third, the authors demonstrated association of effects on low-density lipoprotein cholesterol with measures of stenosis by QCA between several trials of statin therapy. However, because a low-density lipoprotein cholesterol goal of <70 mg/dL was achieved in few patients in previous studies, to examine the impact of low-density lipoprotein cholesterol levels (<70 mg/dL) on QCA variables, it seems appropriate to provide regression analysis within this study (low-density lipoprotein cholesterol versus QCA variables in individual patients), even though no significant correlations were found between the on-therapy lipid levels and changes in the QCA parameters.3
Fourth, in the Discussion section, the authors stated, “We show that 2 imaging modalities, which clearly measure different parameters and focus on different segments of the coronary arteries… Whereas IVUS focuses on the portion of the coronary tree with the least luminal narrowing, QCA focuses on the portion with the greatest luminal narrowing.” However, 1 of 2 primary efficacy parameters in the IVUS study was the change in nominal atheroma volume in the 10-mm subsegment with the greatest disease severity at baseline. Measured segments may have not been different in both IVUS and QCA studies.1,2 To clarify this point, it would be of great help if the authors would clarify how different segments were measured by angiography versus IVUS.
Ballantyne CM, Raichlen JS, Nicholls SJ, Erbel R, Tardif JC, Brener SJ, Cain VA, Nissen SE. Effect of rosuvastatin therapy on coronary artery stenoses assessed by quantitative coronary angiography: A Study to Evaluate the Effect of Rosuvastatin on Intravascular Ultrasound–Derived Coronary Atheroma Burden. Circulation. 2008; 117: 2458–2466.
Nissen SE, Nicholls SJ, Sipahi I, Libby P, Raichlen JS, Ballantyne CM, Davignon J, Erbel R, Fruchart JC, Tardif JC, Schoenhagen P, Crowe T, Cain V, Wolski K, Goormastic M, Tuzcu EM. Effect of very high-intensity statin therapy on regression of coronary atherosclerosis: the ASTEROID trial. JAMA. 2006; 295: 1556–1565.