Intensive Use of Intravascular Ultrasound during Coronary Angioplasty. A Six-month Campaign

Background - Compared to coronary angiography, intravascular ultrasound (IVUS) gives additional information important for the percutaneous transluminal coronary angioplasty (PTCA) procedure, but is time-consuming and may cause complications. Aim - To evaluate, during a period of intensive use of IVUS, the impact of IVUS on the final decision on balloon/stent diameter, consumption of devices, time-consumption and IVUS-related complications. Method - During a 6-month period, IVUS was contemplated in all PTCA procedures and the reason for not using IVUS was specified. We used CVIS during the first, and Endosonics during the last 3 months, and both periods started with 1 week of hands-on practice. All procedures were to be planned according to an initial quantitative coronary angiography (QCA), and the finally achieved result, material used and complications were registered. Results - The proportion of IVUS/PTCA was 37% during, 8% 6 months before and 12% 6 months after the study period. Three hundred and twenty-three patients were included in the study (57% of all patients), 199 of them were subjected to IVUS. The indications for PTCA during the study period were stable angina (58%), unstable angina (32%) and acute myocardial infarction (10%). The main reasons for not doing IVUS were use of 6F guiding catheter (13%), urgent procedure (12%) and occluded vessel (11%). Initial QCA detected 253 stenoses in 199 patients and 64 additional stenoses were treated, most of them probably detected by IVUS. QCA systematically underestimated vessel size, particularly in small vessels. There was a non-significant trend to more accurate estimations towards the end of the study in small vessels. Dissection, probably due to IVUS, occurred in two cases (1%). There were no significant differences in the number of devices used in IVUS compared to non-IVUS patients. The procedural time was 24 min longer in IVUS than in non-IVUS cases and more stenoses were treated per procedure in the IVUS group. Conclusion - Coronary angiography often underestimated balloon/stent size but in an unpredictable way, with a substantial proportion of significant stenoses being undetected. IVUS had few serious complications, did not increase device consumption but prolonged procedural time.