Evaluation Of Intravascular Ultrasound In Percutaneous Coronary Intervention Of Bifurcation Lesion

Objectives: The intervential therapy of coronary artery bifurcation lesion, including the left main (LM) and non-left mian bifurcation, is the nodus of percutanious coronary intervention (PCI) and the side branch(SB) complications in precedure are main issue in this field, such as acute occlusion and aggreviated narrowing. The technique of stenting the main vesseles (MV) crossing SB ostium has been received widely. Most of studies related to SB complications were based on coronary angiography(CAG) and mainly limited to acute occlusion. Few studies were based on intravascular ultrasound (IVUS) and concerned about aggravated narrowing. But, because of the obvious limitation of CAG especially its poor capability in reflecting the morphological character such as plaque quality and spatial distribution, CAG might has some deficency on reflecting the stenositic degree of ostial, the classification of bifurcation and SB complacation. IVUS has been become the principle guiding instrument of PCI and might compensate the limitation of CAG mentioned above. There were some studies about observing plaque distribution using IVUS in coronary bifurcation but none of them performed classification. As we have known, the type of the bifurcation lesion was one of the critical factors for selecting the PCI strategy. Until now, there were few studies about SB complication and the relative mechanism were based on IVUS substantially. This study was designed mainly for three objectives: l:To observate and classify the lesion in left main coronary bifurcation using IVUS. Observing the IVUS character of every practise during and after PCI and analyzing the clinical follow-up outcome;2: To observate and give classification of the plaque distribution of non-left main coronary bifurcation by using IVUS. Analyzing the effection on SB with diameter >=2.0mm of stenting only the main vessels crossing SB ostium innon-left main coronary bifurcation by using IVUS;3: By using IVUS, quantificating analyzing of the morphological changes of SB ostium with diameter >=20mm after main vessel stenting by producing the concept of Deformation Index (DI) the first time and to investigating the potentional significence of the DI.Methords: There were 21 left main coronary bifurcations and 41 non-left main coronary bifurcation lesions. Besides conventional CAG, every patients was preformed IVUS before and after procedure. Observing and classificating the plaque position as well as the plaque morphological characters of left main and non-left main coronary bifurcations repectively. Invesgating the SB complications after MV (LAD) stenting of left main bifurcation interventional therapy. The patients were followed up by telephone and the main adverse cardiac events (MACE) include angina recurrence, Q and non-Q wave myocardium infarction (MI), cardiac sudden death, et al. Compareing analyze SB complications of 35 non-left main bifurcation lesions treated with stenting the main vessels in IVUS and CAG . Visual estimate of plaque shifting was done by IVUS. Detecting the correlated factors of SB complications and morphological characters using Multivarate analyzing. The conception of deformation index (DI) and the calculating fomula(DI= (MaxD-MinD) /MaxD) was proposed first, which was used to describe the morphological changes of SB ostium after MV stenting. Detecting its potential significance in coronary intervention.Results: 1. For left main bifurcation disease, 6 types of bifurcation lesion classification were found according to plaque distribution of the ostium of LAD and LCX, and the distal of left main by IVUS. There was obvious diference between these two types of classification. The tendency of free of disease at the carina was the critical difference between IVUS and CAG classification for coronary bifurcation. Guided by the IVUS classification, the main interventional strategy was Cross-over technique (83.3%). Stent malaposition was the mostcommen complication in all kinds of techniques. In LM-LAD single stenting cross LCX (Cross-over) technique group, LCX acute occlusion rate was 0%, the rate of aggraviated narrowing in IVUS and CAG group was 16.7% and 33.3% respectively. 22.2% patients suffered from angina recurrence in 8.22 ± 1.39m follow-up duration . 2. For 41 non-left main bifurcations, there were 4 types of lesion distribution by IVUS character. Only 2.7% of carina had lesions. In cross-over group, the rate of SB complication in IVUS was lesser than CAG (28.57% vs 37.14%, /?<0.001) respectively. The probable mechanism of SB complication detected by IVUS include plaque shift, vessel wall shrink, spasm and deformation. The DI of SB before and after MV stenting was 0.183 ± 0.133 and 0.265 ±0.165(p<0.0001), the relative factor was plaque eccentric index which showed positive relation to DI. DI was one of correlative factors of MinD of SB ostium measured by CAG. DI was still the indepandent factor by using partial correlation analysis.Conclusions: 1. IVUS could detect coronary bifurcation lesions more accurately than CAG, especiallly the morphological related characters, and CAG might overestimate the SB complication rate after MV stenting. Left main bifurcation PCI guided by IVUS was safe and efficient. IVUS could reflect the mechanism of SB complication directly. The ostium of SB showed the obvious tendency of becoming ellipse which might be the renson of higher complication rate after MV stenting detected by CAG.