May dual-source computed tomography angiography replace invasive coronary angiography in the evaluation of patients referred for valvular disease surgery?

BACKGROUND: Coronary computed tomography (CT) angiography is currently the only alternative to invasive angiography in the evaluation of coronary anatomy. In patients referred for valvular or thoracic aortic disease surgery, invasive coronary angiography remains the gold standard required by cardiac surgeons during the preoperative evaluation. According to the current European Society of Cardiology guidelines, evaluation of coronary anatomy is recommended in all patients above 40 years of age, with a history of coronary artery disease (CAD), in postmenopausal women, patients with left ventricular systolic dysfunction, with suspected ischaemic aetiology of mitral regurgitation, and in patients with one or more risk factors for CAD. The possibility to perform coronary CT angiography to exclude CAD before planned non-coronary cardiac surgery was first allowed in the 2010 Report of the American College of Cardiology Foundation Task Force on Expert Consensus.

AIM: To evaluate the usefulness of dual-source CT for the evaluation of coronary anatomy in patients before planned cardiac valvular surgery.

METHODS: We studied 98 consecutive patients with a haemodynamically significant valvular heart disease and guideline-based indications for coronary angiography to exclude CAD before planned valvular surgery. Exclusion criteria included cardiac arrhythmia (atrial fibrillation, frequent ventricular and supraventricular premature beats), estimated glomerular filtration rate < 60 mL/min/1.73 m(2), allergy to iodine contrast agents, and lack of patient consent. Mean patient age was 58.8 (range 30-78) years. Coronary artery calcium score (CACS) was first determined in all patients. Coronary CT angiography was not performed if CACS was > 1000. In the remaining patients, complete CT evaluation was performed with the administration of a contrast agent. Conventional invasive coronary angiography was subsequently performed in patients with at least one > 50% stenosis, artifacts due to calcifications, or motion artifacts.

RESULTS: In 79 (80.6%) patients, CT angiography excluded the presence of a significant coronary artery stenosis without the need for invasive angiography. Conventional coronary angiography was required in 19 (19.4%) patients, including 13 (13.3%) patients with a > 50% stenosis in CT angiography, 2 (2%) patients with calcification artifacts, 1 (1%) patient with motion artifacts, 2 (2%) patients with CACS > 1000 in whom CT angiography was nor performed, and 1 (1%) patient with allergic symptoms during administration of a test dose of the contrast agent. Ultimately, significant CAD was diagnosed in 9 (9.2%) patients in whom coronary artery bypass surgery was also performed. In addition, vascular anomalies were diagnosed with cardiac CT angiography in 5 (5.1%) patients. In 14 patients, CT angiography was also used for previously planned evaluation of a coexisting aortic aneurysm.

CONCLUSIONS: Coronary CT angiography may be useful to exclude significant CAD in patients referred for valvular disease surgery.