Plaque rupture and morphological characteristics of the culprit lesion in acute coronary syndromes without significant angiographic lesion: analysis by intravascular ultrasound.

PURPOSE: To evaluate by intravascular ultrasound (IVUS) the characteristics of the culprit lesion with plaque rupture without significant angiographic stenosis after acute coronary syndromes (ACS). PATIENTS AND METHODS: After ACS, IVUS was performed in 68 patients (46.8 years±11.9) without significant angiographic stenosis (31±15%). Plaque rupture was defined as a cavity within the plaque, communicating with the arterial lumen and having an overlying residual fibrous cap fragment. Qualitative analysis defined the type of plaque, and quantitative analysis evaluated plaque plus media area, plaque volume, plaque burden, and arterial remodeling index. Patients were divided into two groups: Group I with plaque rupture (25 patients) and Group II without plaque rupture (43 patients). RESULTS: All patients with rupture showed soft or mixed plaque but no calcified plaque. In Group I, plaque rupture was associated with a larger plaque burden (49.8±12.3% vs. 39.8±12.1%, P<.0005), a more significant plaque plus media area (7.44±2.9 vs. 5.24±2.4mm(2), P<.001), a greater plaque volume (151.9±103.4 vs. 99.2±81.6mm(3), P<.007), and a higher ratio of plaque volume over length (8.0±3.8 vs. 5.6±3.7mm(3)/mm, P<.003). In Group I, positive remodeling was more frequent than intermediate remodeling (P<.03) or negative remodeling (P<.005). In Group II, there was no significant difference between the three types of remodeling. CONCLUSION: The plaque ruptures responsible for ACS frequently appear on voluminous plaques with a large plaque burden and positive arterial remodeling.

[Identification of viable myocardium in ischemic heart disease with severe left ventricular contractile dysfunction: comparison of myocardial scintigraphy with 99mTc-sestamabi and with 201-thallium]. / Identification du myocarde viable dans les cardiopathies ischémiques avec atteinte sévère de la fonction contractile du ventricule gauche: comparaison de la scintigraphie myocardique <> au 99mtechnétium-sestamibi et de la scintigraphie myocardique au 201thallium.

The aim of this study was to compare quantitatively uptake of 99mTc-Sestamibi at rest and that of late redistribution of 201Tl in the same patients with severe ischaemic left ventricular dysfunction, and to correlate the uptake of the tracer to regional ventricular dysfunction studied by ECG grated 99Tc-Sestamini. A double isotope myocardial scintigraphy, 201 Thallium at rest/redistribution and 99Tc-Sestamibi at rest and on exercise, was performed in 28 patients with severe postinfarction ischaemic cardiomyopathy (EF= 29 +/- 4%). Quantitative analysis for each patient and each isotope were performed with respect to the number of hits expressed in percentage of the activity of a normal zone in 17 circumferential profiles distributed in 4 zones, that is to say in 476 segments. A score allowed counting of viable and non-viable segments and evaluation of contractile function of the 17 segments with respect to wall motion and systolic thickening. Total concordance of global uptake of the two isotopes was observed in 430 of the 476 segments (90.3%) (r= 0.814, p< 0.0001), but the 99mTc-Sestamibi uptake was less than 201 Th (71 +/- 23% vs 73 +/- 21%, p= 0.0001). With respect to left ventricular wall motion, uptake of 99mTc-Sestamibi was greater than that of 201Tl in normal or hypokinetic segments but less in akinetic and dyskinetic segments. The difference between the two isotopes was most marked in segments with very severe contractile dysfunction. The authors conclude that the uptake of 99mTc-Sestamibi is correlated with that of late distribution of 201Tl when left ventricular contraction is not too poor and should no longer be considered as only a marker of perfusion but can also be useful in the investigation of myocardial viability.

[Endo-coronary ultrasonography: significance of the images]. / Echographie endocoronaire: signification des images.

In addition to the assessment of the arterial lumen and coronary stenosis, endocoronary ultrasonography also provides information in vivo on the nature of atheromatous plaque. This study reports the preliminary correlations between the echographic appearances, the functional status of the patients and histological data of tissue obtained by directional atherectomy. The appearances of atheromatous infiltrations help distinguish stable forms of coronary disease with "hard", hyperreflective plaques, from acute forms with "soft" hyporeflective plaques. Ultrasonography confirms the clinico-pathological relationship of myocardial infarction and unstable angina with, in the acute forms, a similarity of the culprit plaques which appear vulnerable, hyporeflective and often complicated by the association of fissures and thrombus. The correlations with histological data are still incomplete. However, the "soft" nature of the plaque is an expression of its cellularity and lipid content whereas "hard" plaques correspond to increased fibrous tissue. These associations have no correlative values as yet. Nevertheless, they establish a parallelism which may eventually explain the functional variability and evolutivity of coronary artery disease. In the same way that visualisation of coronary stenosis led to the development of coronary artery surgery and later to angioplasty, observation of the plaque by ultrasonography should promote the development of pharmacological agents to treat the atheromatous lesions.

The safety of intracoronary ultrasound. A multicenter survey of 2207 examinations.

BACKGROUND: Intracoronary ultrasound (ICUS) is increasingly used in clinical practice to study the natural history of coronary artery disease and to assess the effects of intracoronary, catheter-based interventions. However, the risk associated with the procedure is not well documented. METHODS AND RESULTS: ICUS studies performed in 28 centers were retrospectively included; these centers agreed to contribute to the study among a total of 60 centers initially invited. Among the 2207 ICUS studies, 505 (23%) were performed in heart transplant recipients and 1702 (77%) in nontransplant patients. Indication for ICUS was diagnostic imaging in 915 (41%), drug testing in 244 (11%), and guidance for intracoronary interventions in 1048 patients (47%). There were no complications in 2034 patients (92.2%). In 87 patients (3.9%), complications occurred but were judged to be "not related" to ICUS by the operator. In 63 patients (2.9%), spasm occurred during ICUS imaging. In 9 patients (0.4%), complications other than spasm were judged to have a "certain relation" to ICUS, including acute procedural events in 6 (3 acute occlusion, 1 embolism, 1 dissection, and 1 thrombus) and major events in 3 patients (2 occlusion and 1 dissection; all resulting in myocardial infarction). In 14 patients (0.6%), complications with "uncertain relation" to ICUS were recorded, including acute procedural events in 9 (5 acute occlusion, 3 dissection, and 1 arrhythmia) and major events in 5 patients (2 myocardial infarction and 3 emergency coronary artery bypass surgery). The incidence of acute procedural or major complications judged to be associated with ICUS (uncertain relation or certain relation to ICUS) was compared in different patient groups. The complication rate was higher in patients with unstable angina or acute myocardial infarction (2.1% events) as compared with patients with stable angina pectoris and asymptomatic patients (0.8% and 0.4%, respectively; chi 2 = 10.9, P < .01). These complications were also more frequent in patients undergoing interventions (1.9%) as compared with transplant and nontransplant patients undergoing diagnostic ICUS imaging (0% and 0.6%, respectively; chi 2 = 13.5, P < .001). Adverse events were few, and no association was detected between these events and the size or type of ICUS catheter used. CONCLUSIONS: ICUS is associated with (but not necessarily the direct cause of) a minor acute clinical risk. Vessel spasm is the most frequent event occurring during ICUS. Other complications predominantly occur in patients with acute coronary syndromes and during guidance for intervention.