13 Jul Coronary CT Able To Exclude Significant CAD in Patients Scheduled for Valve Surgery

MedicalResearch.com Interview with:

Dr. Maksymilian Opolski

Dr Maksymilian P. Opolski
Department of Interventional Cardiology and Angiology
Institute of Cardiology
Warsaw, Poland

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Valvular heart disease (VHD) that requires surgery is increasingly encountered in industrialized countries. Of particular interest, the presence of concomitant coronary artery disease (CAD) in patients with VHD is related to worse clinical outcomes, and various clinical studies suggested that combined valve and bypass surgery reduces early and late mortality. Consequently, in the majority of such patients, pre-operative evaluation for coronary artery disease (CAD) with invasive coronary angiography is recommended. However, provided that most patients with valvular heart disease are found to have no significant coronary stenoses, coronary computed tomography angiography (coronary CTA) appears as an extremely appealing noninvasive alternative to invasive coronary angiography for exclusion of significant CAD. This is further justified when the risks of angiography outweigh its benefits (e.g. in cases of aortic dissection or aortic vegetation).

According to European guidelines for the management of  valvular heart disease, coronary CTA should be considered before valve surgery in patients with low probability for CAD (excluding a significant number of patients such as men over 40 years, postmenopausal women and subjects with at least 1 cardiovascular risk factor, suspected myocardial ischemia or left ventricular systolic dysfunction). Further, the level of evidence for this Class IIa recommendation is only C, and certainly needs verification. Of note, in recent years, several single-center studies have tested the diagnostic performance of coronary CTA in patients undergoing cardiac valvular surgical treatment. We have thus performed a comprehensive meta-analysis of all available studies comparing ≥16-detector row coronary CTA with invasive coronary angiography for the detection of significant coronary stenoses in patients scheduled for elective valve surgery.

In all, we have included 17 studies with 1,107 patients and 12,851 coronary segments. Our main finding was that coronary CTA using currently available technology can reliably rule out significant coronary stenoses in patients scheduled for valve surgery compared with the clinical standard of invasive coronary angiography. Thus, coronary CTA may serve as an effective gatekeeper for coronary catheterization, and invasive coronary angiography may not be required in all patients with VHD referred to cardiac surgery. Importantly, the ability of coronary CTA to detect significant coronary stenoses in patients with VHD is not universal and was lower for subjects with aortic valve stenosis, a finding possibly reflective of the higher prevalence of atherosclerosis. Conversely, the specificity of coronary CTA for the detection of significant CAD was higher for CT scanners with at least 64 detector rows, confirming a steady progress with the latest and most advanced scanner generations.

MedicalResearch.com: What should readers take away from your report?

Response: The take-home message from our report is that coronary CTA using currently available technology provides excellent diagnostic performance for the exclusion of significant coronary stenoses in patients scheduled for valve surgery. This, in turn, makes the computed tomographic approach a reliable noninvasive alternative to invasive coronary angiography with a potential for reduction of unnecessary downstream testing as well as catheter-related complications and costs prior to cardiac valve surgery. We believe that our study is a major step forward in better understanding which patient populations might be most suitable for coronary CTA to rule out the presence of significant CAD. Notably, the findings from this study may be considered widely generalizable given the high number of included patients across a wide range of diverse clinical centers.

But despite good accuracy in excluding obstructive CAD, the positive likelihood ratio of coronary CTA to detect significant coronary stenoses was reduced against the background of aortic valve stenosis.

Similarly, the use of CTA with <64 detectors (hopefully rarely applied nowadays) was still inadequate for the detection of significant CAD, likely as a result of worse spatial and temporal resolution. Thus, invasive coronary angiography is still needed to confirm or refute a positive CT angiography in these clinical scenarios.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: Future studies are needed to further specify the most suitable candidates for coronary CTA before cardiac valve surgery with regard to pretest probabilities of CAD. Furthermore, evaluation of the impact of coronary CTA on therapeutic management is critical. In this regard, initiation of a randomized clinical trial investigating the influence of coronary CTA versus invasive coronary angiography on the management and outcomes (including downstream testing and costs) of patients with VHD scheduled for valve surgery is imperative to galvanize the eventual implementation of coronary CTA into standard clinical care. Moreover, whereas the image acquisition and reconstruction protocols of coronary CTA are constantly being developed, large-scale prospective clinical trials comparing radiation and contrast exposure between coronary CTA and invasive coronary angiography among patients with VHD now seem warranted. Finally, another open research question is whether CTA could substitute invasive coronary angiography in patients referred for transcatheter aortic valve implantation.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.

Citation:

CT Angiography for the Detection of Coronary Artery Stenoses in Patients Referred for Cardiac Valve Surgery: Systematic Review and Meta-Analysis.

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Last Updated on July 13, 2016 by Marie Benz MD FAAD