ABSTRACT
We tested this approach in a prospective study performed between April 1997 and June 1999, which included 146 consecutive patients with 173 lesions. The flow chart for this study is shown in Figure 3.1. The operator evaluates by visual estimate if the lesion to be treated is a long lesion which needs this approach. In general, this decision is taken if the lesion is too long to be treated with a single inflation of a 20 mm long balloon. Long lesions (15 mm) are initially approached with PTCA, utilizing a balloon-toartery ratio of 1 : 1. At the discretion of the operator, IVUS is performed prior to balloon dilatation, and the size of the first balloon is selected according to the IVUS media-to-media measurements. This means that the first step is to perform a preintervention IVUS evaluation. If this initial IVUS assessment is not possible or the operator prefers to defer this first IVUS evaluation, the lesion is first dilated with a balloon sized according to angiography. If extensive calcium is present, rotational atherectomy (Rotablator) can be performed before PTCA. If during balloon dilatation the balloon does not completely expand at 10-12 atm, a cutting balloon can be used. A cutting balloon is indicated if the IVUS study shows a fibrotic or moderately calcified lesion. If, after initial PTCA balloon dilatation, the IVUS criteria are met in all segments of the lesion, the procedure is considered complete. Criteria for success based on IVUS evaluation are: (1) achievement of a lumen cross-sectional area 50% of the vessel crosssectional area at the lesion site; or (2) a minimum true lumen cross-sectional area 5.5 mm2. These success criteria are defined independently of the presence of a dissection, as long as the true lumen cross-sectional area is adequate and meets our prespecified lumen cross-sectional area criterion, and thromolysis in myocardial infarction (TIMI) grade 3 flow is present. If the IVUS criteria are not met, the operator may consider using a bigger balloon or higher pressure, according to lesion morphology
Figure 3.1 Flow diagram of IVUS-guided PTCA with spot stenting.
