Routine CT angiography to detect severe coronary artery disease prior to transcatheter aortic valve replacement

Patients undergoing TAVR undergo routine CT angiography (CTA) to assess aorto-iliac pathology and annular dimensions. While coronary CTA may exclude severe CAD in younger patients, its efficacy in defining CAD severity prior to TAVR may be limited. We retrospectively studied 50 consecutive patients undergoing both invasive coronary angiography (ICA) and routine pre-TAVR CTA. Severe CAD was defined as ≥50% stenosis by quantitative coronary angiography and compared to a blinded CTA visual estimation of ≥50% stenosis. The analysis was confined to four segments: left main and three proximal to mid major coronaries to maximize myocardial territory at risk. Coronary assessment was performed using standard reconstructed ECG phases from pre-TAVR chest CTA on a Philips 256 iCT scanner. Nearly ¾ of patients were ≥75 years old, 57% were female, half were diabetic and 45% had prior PCI. By ICA, 49% had significant coronary calcification. The incidence of severe proximal to mid vessel CAD by ICA was 39%. Similarly, a third of patients required PCI prior to TAVR. CTA was unable to exclude severe proximal to mid vessel CAD in 88% of patients in all four segments: non-diagnostic CTA readings were mainly due to calcification (60%) or motion artifact (28%). Non-diagnostic coronary CTA readings ranged from 25 to 72% according to segment analyzed: only the left main segment had diagnostic quality CTA in the majority of patients (p < 0.01). PCI is performed frequently prior to TAVR based upon invasive coronary angiographic assessment. Routine chest CTA algorithms do not provide adequate diagnostic information to exclude severe CAD, primarily due to severe coronary calcification in the TAVR population.