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30-06-2011 | Cardiology | Article

Noninvasive CV imaging has ‘unclear’ impact on primary prevention


Free abstract

MedWire News: Noninvasive cardiovascular (CV) imaging does not have a major influence on primary prevention efforts, researchers suggest.

Reasons put forward for use of imaging to detect subclinical CV disease include that it may increase patients' motivation to adopt a healthier lifestyle, and help refine risk prediction - which in turn impacts on clinical decision-making.

However, "despite extensive use in practice, the impact of noninvasive CV imaging in primary prevention remains unclear," write Daniel Hackam (University of Western Ontario, London, Canada) and colleagues in the Archives of Internal Medicine.

The researchers performed a meta-analysis of randomized trials that compared imaging with usual care in a primary prevention setting, and reported the following outcomes: medication prescribing, lifestyle modification (including diet, physical activity, or smoking cessation), angiography, or revascularization.

Of the seven trials included, two screened patients for inducible myocardial ischemia, three for coronary calcification, one for carotid atherosclerosis, and one for left ventricular hypertrophy.

The trials enrolled a median of 153 patients (45% women) with a median age of 55 years, and followed up patients for a median of 12 months. Screening methods included ultrasonography, echocardiography, exercise stress test, computed tomography, and myocardial perfusion imaging.

Findings revealed that imaging had no effect on medication prescribing overall (odds ratio [OR]=1.01, 95% confidence interval [CI]=0.76-1.33), or on the provision of lipid-modifying agents (OR=1.08, CI=0.58-2.01), antihypertensive drugs (OR=1.05, CI=0.75-1.47), or antiplatelet agents (OR=1.05, CI=0.84-1.32).

Similarly, no effect was observed for dietary improvement (OR=0.78, CI=0.22-2.85), physical activity (0.02 vs -0.08 point change for imaging vs control on a 5-point scale, p=0.23), or smoking cessation (OR=2.24, CI=0.97-5.19). Furthermore, imaging was not associated with invasive angiography (OR=1.26, CI=0.89-1.79).

Hackam et al point out that limitations of their study include its small sample size and potential reporting biases from individual trials, and recommend that more large-scale, high-quality studies be conducted.

"Given the low rate of CV events in most primary prevention populations accrued in the modern era, imaging trials powered for CV events will either need to include very large populations or induce greater shifts in the intensity and prevalence of evidence-based medical therapies," they conclude.

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Piriya Mahendra

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