Abstract
OBJECTIVE: To compare the quantity, subtype, and progression of atherosclerosis by cardiac computed tomography (CT) and intravascular ultrasound (IVUS) in patients with stable (SAP) and unstable angina pectoris or non-ST-elevation myocardial infarction (UAP/n-STEMI). METHODS: Forty patients with SAP and 20 with UAP/n-STEMI underwent cardiac CT and angiography with IVUS at baseline and after one year. Atherosclerotic segments were divided into calcified, mixed, or noncalcified subtypes, and significant stenoses were registered. RESULTS: Thirty-two SAP and 15 UAP/n-STEMI patients completed the CT follow-up. At baseline, the number of atherosclerotic segments was higher in UAP/n-STEMI than in SAP (P = 0.039). UAP/n-STEMI patients had more segments with noncalcified plaques (P = 0.0005) whereas SAP patients had more segments with calcified plaques (P = 0.013). The number of segments with significant stenosis did not differ between the groups, but noncalcified plaques more frequently caused significant stenoses in UAP/n-STEMI than in SAP patients (P = 0.0002). After one year the number of segments with atherosclerosis increased in SAP patients (P = 0.0001). The number of atherosclerotic segments remained unchanged in UAP/n-STEMI patients. However, composition was altered as the number of segments with noncalcified plaques decreased (P = 0.018). IVUS data confirmed the CT findings. CONCLUSION: Quantity, subtype, and progression of atherosclerosis differ between SAP and UAP/n-STEMI patients.