Use of coronary computed tomography angiography in clinical practice - single centre experience in Switzerland in light of current recommendations based on pretest probability considerations

Abstract

Aims of the study: Coronary computed tomography angiography (CCTA) is recommended as a first-line option for the exclusion of coronary artery disease in patients with low to intermediate (15–50%) pretest probability. We aimed to study the use of CCTA in clinical practice in a single centre in Switzerland in light of this recommendation.

Methods: In 523 consecutive patients (age 56 ± 13 years, 48% females) undergoing CCTA during a period of 2 years, the pretest probability of coronary artery disease was assessed using the revised Diamond-Forrester model (CAD consortium score). In patients who had invasive coronary angiography following CCTA, angiographic findings and the consequences regarding management are reported.

Results: The majority of patients (n = 316; 60%) had a pretest probability <15%, 188/523 (36%) had a pretest probability between 15 and 50%, and 19/523 (4%) had a pretest probability >50%. The prevalences of coronary artery disease (≥50% lumen diameter reduction) by CCTA in patients with pretest probability <15%, 15–50%, and >50% were 25/316 (8%), 45/188 (24%) and 8/19 (42%), respectively. In 438/523 patients (84%), a CCTA scan showing no coronary artery disease represented the final diagnostic step. In patients undergoing invasive coronary angiography (n = 59, age 58 ± 9 years, 88% with coronary artery disease by CCTA), coronary artery disease was found in 47/59 (80%) patients and 36/59 (61%) patients underwent revascularisation. The prevalences of coronary artery disease by invasive coronary angiography in patients with pretest probability <15%, 15–50%, and >50% were 14/21 (67%), 28/32 (88%) and 5/6 (83%).

Conclusions: The present data suggest that the currently used pretest probability model is still imperfect and that guideline recommendations regarding pretest probability use for the selection of CCTA candidates are not followed completely. Still, in more than 80% of patients coronary artery disease could be excluded by CCTA, while CCTA also detected a significant number of patients with coronary artery disease in the low pretest probability population. Thus, the data suggest a very judicious use of CCTA as a gatekeeper for invasive coronary angiography in current practice.