Statin slows coronary artery calcification

Mon, 05 Aug 2002 20:00:00

Munich, Germany - Lipid-lowering drugs may slow the progression of coronary artery calcification, new research suggests. Whether changes in coronary calcification seen on electron-beam computed tomography (EBCT) due to statin therapy actually translate into alterations in atherosclerotic plaque volume, composition, or vulnerability is still uncertain, the authors say.

Their study appears online in the August 6, 2002 rapid access issue of Circulation.

The popularity of fast CT scans for the detection and quantification of coronary artery calcification (CAC) is both booming and controversial, due in part to the aggressive marketing of the technology. Studies linking high calcium scores to presence of coronary disease and the risk of MI or stroke are proliferating, but skeptics of the modality point out that the added benefits of EBCT remain to be seen. In July 2000, an AHA/ACC consensus group concluded that the EBCT scan has proved "to have a predictive accuracy approximately equivalent to alternative methods for diagnosing coronary artery disease but has not been found to be superior to alternative noninvasive methods."

Progression of calcification slowed or halted

Tackling the topic from a new angle, Dr Stephan Achenbach (University of Erlangen-Nürnberg, Germany) and colleagues evaluated 66 patients with CAC detected by EBCT who had follow-up scans roughly 1 year after their first scan, during which time they took no lipid-lowering medications, then again after an additional 12 months on cerivastatin.

[Cerivastatin (Baycol®/Lipobay® - Bayer) was pulled from markets around the globe following reports of fatal rhabdomyolysis. In Germany, Achenbach et al's study was terminated prematurely and with fewer patients than initially intended due to the withdrawal of the drug.]

They found that the mean volume of CAC increased from 155 mm³ at baseline to 201 mm³ after 1 year on no medication. By contrast, during the subsequent year when the study subjects were taking cerivastatin, mean volume of CAC increased only marginally, to 203 mm³. During this same period, LDL and total cholesterol levels decreased significantly from pretreatment levels.

Strikingly, in 32 patients whose LDL levels fell below 100 mg/dL during the year on cerivastatin, CAC did not progress at all.

Measure of CAC, cholesterol, and triglycerides over 2-year period

Measure	Baseline	12 months, untreated	12 months, cerivastatin	p value
	155	201	203	0.01*
		164+30	107+21	<0.0001
		51+12	52+12	0.3
		184+106	152+68	0.004
		244+32	188+28	<0.0001

*p value reflects comparison of CAC increase between baseline and 12 mo vs increase between untreated and treated periodTo download the table as a slide, click on the slide logo below

"Progression of coronary calcification was significantly less pronounced during treatment with cerivastatin compared with the period before treatment was initiated," Achenbach and colleagues write.

They conclude that changes in CAC likely point to "activity" of the atherosclerotic process and that quantification of CAC using fast CT techniques may be a promising tool for assessing disease progression. Nonetheless, "the relationship between changes in the amount of CAC and changes in overall plaque burden and plaque vulnerability deserves additional investigation.

Noncardiac findings on EBCT "obligation" of physician reading scan

In a separate study appearing in the July 30, 2002 issue of Circulation, Dr Karen M Horton (Johns Hopkins Medical Institutions, Baltimore, MD) et al call for closer examination of noncardiac pathologies appearing on EBCT and multidetector-row (MDCT) scans. Horton and colleagues point out that more and more people are getting fast CT scans in the hopes of detecting early heart disease, but that scans typically also image portions of the lungs, chest wall, spine, and upper abdomen where other early-stage diseases may be visible on the scans.

Out of 1326 patients who underwent EBCT scans, Horton and her coinvestigators found 103 had "significant extracardiac pathologies" requiring clinical or imaging follow-up. The most common finding was noncalcified lung nodules (<1cm in 53 patients; >1cm in 12 patients), liver lesions, sclerotic bone lesions, breast abnormalities and other liver and esophageal abnormalities were also seen.

The scientific literature contains limited references to noncardiac pathologies seen on fast CT, the authors note. Indeed, many scans are read only by cardiologists "who are primarily concerned with the cardiac portion of the examination," they write, despite the fact that noncardiac problems can also be picked up, often at an early stage in disease processes, by CT scanning.

"We believe that is should be the responsibility and obligation of the physician interpreting the cardiac CT scan to review the entire study, including the lungs and bones," Horton et al conclude. "A qualified radiologist should review the entire examinations, even if a cardiologist has performed the coronary artery calcification scoring, to avoid missing potentially important pathology."

-SW

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Statin slows progression of coronary artery calcification: EBCT findings

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