Volumetric assessment of ulcerated ruptured coronary plaques with three-dimensional intravascular ultrasound in vivo.

Abstract

I ultrasound (IVUS) permits transmural visualization of coronary arteries to assess the vessel wall, including plaque rupture sites.1–9 Three-dimensional IVUS provides volumetric data and permits deeper insights into the architecture of coronary lesions.10–12 In the present study, we assessed ruptured coronary plaques in vivo using 3-dimensional IVUS to evaluate the potential relation between the volume of the emptied plaque cavity versus lesion characteristics and dimensions. We hypothesized that rupture and ulceration of larger coronary plaques may be associated with larger dimensions of the ulcerated cavities, indicating that more material must be embolized from the core of these atheromas. • • • The study population consisted of 29 patients with symptomatic coronary artery disease who were referred to our hospital for percutaneous coronary intervention and had a ruptured coronary plaque identified by IVUS in a previously untreated coronary artery. No patient had received glycoprotein IIb/IIIa antagonists or thrombolytic therapy. Plaques had to meet the following IVUS criteria: (1) high-quality images of the entire lesion segment as well as the proximal and distal reference segments, (2) nonostial lesion location, (3) calcification that did not limit quantitative assessment of external elastic membrane cross-sectional area or volume, or no calcification, (4) absence of side branches between the lesion and the proximal and distal reference segments, and (5) absence of very angular segments on angiography to permit reliable IVUS volumetric measurements. Of 51 patients with IVUS documented plaque rupture, 29 fulfilled these criteria. The study was approved by the Local Council on Human Research. All patients signed a written informed consent form, approved by the local medical ethics committee. Cardiovascular risk factors that were recorded included diabetes mellitus (medicationdependent only), hypertension (medication-dependent only), hypercholesterolemia (medication-dependent or total serum cholesterol 200 mg/dl), a history of smoking, and a family history of coronary artery disease. All patients were on aspirin and received adequate doses of heparin intravenously. Procedures were performed by the femoral approach using standard 8Fr guiding catheters. IVUS imaging was performed after intracoronary injection of 200 g of nitroglycerin and before any coronary intervention. All IVUS studies were performed with a mechanical sector scanner (Boston Scientific Corporation, Maple Grove, Minnesota) incorporating a 30-MHz single-element beveled transducer rotating at 1,800 rpm. The transducer was withdrawn automatically using a motorized pull-back device (0.5 mm/s). All pullbacks were started as distal as possible and the entire artery was imaged to the aorto-ostial junction. In addition, the site of the plaque rupture was examined using manual interrogation; bolus injections of dye and saline were performed to confirm the presence of plaque rupture as previously described (injections were performed during manual interrogation).2,8 The examinations were recorded on 0.5-in high resolution super-VHS tape for off-line From the Department of Cardiology, Essen University, Essen, Germany; and Cardiovascular Research Foundation, New York, New York. Dr. von Birgelen’s address is: Essen University, Department of Cardiology, Center of Internal Medicine, Hufelandstr. 55, D-45122 Essen, Germany. E-mail: von.birgelen@uni-essen.de. Manuscript received December 3, 2002; revised manuscript received and accepted January 7, 2003. FIGURE 1. Longitudinal IVUS reconstruction of ruptured plaque in the mid right coronary artery. Small arrowheads in the longitudinal (A) and transversal (B) IVUS images indicate the site of the plaque rupture, which was located in the proximal (upstream) shoulder of the plaque. Large dotted arrowhead, direction of blood flow. External elastic membrane (EEM), lumen and plaque cavity (CY) area were measured on each image slice of the lesion segment (C). Thin line in (B) and (C), the plane of the longitudinal reconstruction (A).