Evaluation of Coronary Plaque Characteristics with Coronary Computed Tomography Angiography in Patients with Non-obstructive Coronary Artery Disease: a Long-term Follow-up Study

Aims: Recent studies suggested that even non-obstructive coronary artery disease (CAD) increases major cardiovascular adverse events (MACE) rate. Aim of this study was to evaluate whether coronary computed tomography angiography (CCTA) may detect specific plaque characteristics that may affect prognosis in patients with non-obstructive CAD.

Methods: We enrolled 245 patients who underwent CCTA between April 2004 and April 2007 for suspected CAD and were found to have non-obstructive CAD. Positive remodelling index (PRI), low-attenuation plaque (LAP), plaque burden (PB), spotty calcification (SC), and napkin-ring sign (NRS) have been evaluated for each coronary plaque detected. Acute coronary syndrome, all-cause/cardiac death, and very late elective revascularization (vl-ER) were the endpoints of the study.

Results: A total of 28 events were recorded (2 STEMI, 4 NSTEMI, 6 UA, 2 cardiac deaths, 4 non-cardiac death, and 10 vl-ERs) at long-term follow-up (98 ± 20 months). When adjusted for significant clinical variables PRI > 1.4 (HR 3.31 CI 95% 1.11-9.91, P = 0.0392), LAP (HR 8.45 CI 95% 2.22-32.21, P = 0.0019), PB > 0.7 (HR 5.25 CI 95% 1.45-19.03, P = 0.0120), and NRS (HR 12.52 CI 95% 1.51-103.90, P = 0.0198) were still significantly associated with higher rate of hard cardiac events at follow-up. The Kaplan-Meyer curves confirmed lower cumulative hard cardiac events-free survival in patients presenting at least one coronary plaque with two or more high-risk characteristics when compared with patients with no lesion with more than one high-risk plaque characteristics (log-rank P < 0.0001).

Conclusions: High-risk plaque characteristics at CCTA (PRI > 1.4, PB > 0.7, LAP, and NRS) seem to be promising for risk stratification of patients with non-obstructive CAD.