[Intravascular ultrasound. Initial experience and review of the literature]

From February 1995 to February 1996, 52 patients underwent intravascular ultrasound (IVUS) imaging: three with aortic coarctation (AoCo), one with persistent ductus arteriosus (PDA), 5 with rheumatic heart disease (RHD) and normal coronary arteries by angiography, one with muscular bridge in anterior descending artery, 20 with percutaneous transluminal coronary angioplasty PTCA (Group I), one of them with eximer laser and 22 stents (Group II). In patients with AoCo was possible to observe obstruction mechanism and the effect of dilation. In patient with PDA we measured the diameter of ductus. In patients with RHD we found early atherosclerosis in four cases, no detected by angiography. In Group I, we found soft plaque in 8, fibrous/mixed in 7 and calcified plaque with the calcium located superficially near the lumen in 5, concentric in 6 and 14 eccentric plaques. In this group the objective was observational in most of the cases, except when the imaging was characteristic of mayor dissection or small final lumen. In 10 cases we observed fracture or dissection of the plaque, in some with small flaps into the lumen. In the last two cases, IVUS was used to optimize results after PTCA in one, in the other we postponed the procedure because the characteristics of the lesion (severe superficial calcification). The patient who underwent eximer laser, IVUS demonstrated irregular and small lumen and was followed by PTCA. In Group II, IVUS was used to optimize deployment of stents. We did not have any case with subacute thrombosis.

Only four cases had angina with ischemic ECG changes during the procedure, but reverted after catheter pullback and intracoronary nitroglycerin. In summary, IVUS gives information about mechanism of obstruction, its complications and results of PTCA. Also detect early atherosclerotic disease not observed by angiography. Optimize deployment of stents and avoids cumarinic anticoagulation in most of the patients. Rational selection of device or deferral of the procedure is possible if we know the characteristics of the plaque before intervention. Utility in other cardiovascular diseases is limited at this time. It's a safe procedure, the morbidity is low and in our experience, without mortality. In the future this new technology will bring useful information in other types of coronary arteries diseases.