Limitation of angiography to identify the culprit plaque in acute myocardial infarction with coronary total occlusion utility of coronary plaque temperature measurement to identify the culprit plaque.

OBJECTIVES: The purpose of this study was to test the hypothesis that the maximal temperature (Tmax) site, as measured by thermal wire, coincides with the culprit plaque by intravascular ultrasound (IVUS) in patients with acute myocardial infarction (AMI). BACKGROUND: Subsequent thrombosis developing to the proximal region from the site of plaque rupture or erosion can potentially complicate the ability of coronary angiography to identify the accurate culprit plaque in patients with coronary total occlusion. METHODS: In 45 consecutive patients with a first anterior AMI, the Tmax site by thermal wire and the culprit plaque by IVUS were evaluated in the left anterior descending coronary artery (LAD). RESULTS: Twenty-five patients had LAD total occlusion, and the remaining 20 had LAD reperfusion. In both groups of patients, the Tmax site was significantly more distal to the angiographically most stenotic site or occlusive site (reperfusion: mean distance [MD] = 1.1 mm distal, 95% confidence interval [CI] 0.3 to 1.9 mm, p = 0.01; total occlusion: MD = 8.8 mm distal, 95% CI 8.0 to 9.6 mm, p < 0.0001). The culprit plaques by IVUS approximately coincided with those by angiography or thermal wire in patients with reperfusion. However, the angiographic occlusive site was significantly more proximal to the culprit plaque by IVUS (MD = 9.2 mm, 95% CI 7.9 to 10.6 mm, p < 0.0001), but the Tmax site coincided with the culprit plaque by IVUS (MD = 0.3 mm distal, 95% CI 0.3 mm proximal to 1.0 mm distal, p = 0.293) in patients with total occlusion. CONCLUSIONS: Temperature measurement of coronary plaque enables accurate localization of the culprit plaque in AMI with coronary total occlusion.     

Impact of coronary artery remodeling on clinical presentation of coronary artery disease: an intravascular ultrasound study

OBJECTIVES: We examined the association between the features of the culprit lesion in coronary artery disease (CAD) and clinical presentation as shown by intravascular ultrasound (IVUS). BACKGROUND: The association between coronary remodeling pattern and clinical presentation of CAD is unclear. METHODS: We analyzed 125 selected patients who underwent preintervention IVUS. Acute myocardial infarction (AMI) and unstable angina pectoris (UAP) were categorized as an acute coronary syndrome (ACS), and stable angina pectoris (SAP) and old myocardial infarction (OMI) as stable CAD. Coronary remodeling patterns and plaque morphology of the culprit lesion obtained by IVUS were analyzed in terms of their association with clinical presentation or angiographic morphology. RESULTS: Angiographically complex lesions were associated with ACS and OMI. In patients with a complex lesion, positive remodeling was observed more frequently than in those with a simple lesion. In AMI and UAP, positive remodeling was observed more frequently than in SAP and OMI (82% vs. 78% vs. 33% vs. 40%, respectively, p < 0.0001). The remodeling ratio was greater in AMI and UAP than in SAP and OMI (1.26 +/- 0.15 vs. 1.11 +/- 0.10 vs. 0.94 +/- 0.11 vs. 0.96 +/- 0.13, respectively, p < 0.0001). Furthermore, within ACS, the remodeling ratio was greater in AMI than in UAP (1.26 +/- 0.15 vs. 1.11 +/- 0.10, respectively, p < 0.05), whereas the frequency of positive remodeling was not different. CONCLUSIONS: Positive remodeling was more frequently observed in ACS than in stable CAD. Moreover, the degree of positive remodeling was greater in AMI than in UAP. These results may reflect the impact of remodeling types and its degree in the culprit lesion of CAD on clinical presentation.     

Independent roles of monocyte chemoattractant protein-1, regulated on activation, normal T-cell expressed and secreted and fractalkine in the vulnerability of coronary atherosclerotic plaques

Background:?Monocyte chemotactic factors contribute to the formation of atherosclerotic plaques. The present study aimed to elucidate the roles of monocyte chemoattractant protein-1 (MCP-1), Regulated on Activation, Normal T-cell Expressed and Secreted (RANTES) and fractalkine on the vulnerability of atherosclerotic plaques in patients with acute myocardial infarction (AMI) or unstable angina pectoris (UAP). Methods and Results:?Sixty patients with AMI, 60 patients with UAP, 60 patients with stable angina pectoris (SAP) and 40 patients without coronary heart disease comprised the study group. Quantitative coronary angiography and intravascular ultrasound (IVUS) were performed. Concentrations and mRNA expression levels of high-sensitivity C-reactive protein, MCP-1, RANTES and fractalkine were measured by ELISA and RT-PCR, respectively. IVUS found that 51.3% of the AMI patients and 47.7% of the UAP patients had soft lipid plaques. Among the SAP patients, 52.4% had fibrous plaques and only 17.1% had soft plaques. AMI and UAP patients had larger plaque burden and vascular remodeling index than did the SAP patients (P<0.01). The averaged number of migrated monocytes was higher in AMI and UAP patients. Concentrations and mRNA expression levels of MCP-1, RANTES and fractalkine were significantly higher in AMI and UAP patients than in SAP patients (P<0.05-0.01). The plaque burden in UAP patients as measured with IVUS correlated well with monocytes chemotaxis (r=0.56, P<0.01). Conclusions:?MCP-1, RANTES and fractalkine independently participate in the pathogenesis of plaque vulnerability and subsequent plaque rupture. (Circ J?2012; 76: 2167-2173).     

The Different Patterns of Coronary Artery Calcification in Acute and Chronic Coronary Syndromes Determined by Electron Beam Computed Tomography

Objectives To compare the different patterns of coronary artery calcification (CAC) in acute and chronic coronary syndromes utilizing electron beam computed tomography. Background Pathologic, angiographic, and intracoronary ultrasound studies revealed sharp differences in the plaque morphology between patients with acute versus chronic coronary syndromes. Whether there are different patterns of coronary artery calcification in patients with stable angina pectoris (SAP) and in those with unstable angina pectoris (UAP) or acute myocardial infarction (AMI), however, remains unclear. Methods Two hundred and sixty - four patients, including 67 with SAP, 94 with UAP and 103 with AMI were studied with electron beam computed tomography for analysis of coronary artery calcification and with selective coronary angiography for determination of atherosclerotic lesions. CAC prevalence and calcium score were compared among three groups, and relation of CAC to the severity of atherosclerotic disease in the SAP and UAP     

Impact of plaque rupture on infarct size in ST-segment elevation anterior acute myocardial infarction.

OBJECTIVES: We sought to assess whether coronary plaque rupture at culprit lesions is associated with infarct size in patients with anterior acute myocardial infarction (AMI). BACKGROUND: Some patients with AMI have large infarcts despite early reperfusion. Whether culprit plaque morphology impacts infarct size or not remains unknown. METHODS: Patients who had a first anterior AMI with reperfusion within 6 hours after onset were enrolled and divided into 2 groups according to the presence or absence of plaque rupture at the culprit lesion as defined by preintervention intravascular ultrasound (IVUS): patients with rupture (n = 54) and without rupture (n = 37). RESULTS: Patients with plaque rupture had a higher incidence of no-reflow phenomenon (15% vs. 3%; p = 0.08) and a lower myocardial blush grade (1.5 vs. 2.3; p < 0.05) after percutaneous coronary intervention. The IVUS analysis showed that patients with plaque rupture had a higher incidence of soft plaque and positive remodeling. Peak creatine kinase levels were higher (4,707 vs. 2,309 IU/l; p < 0.0001) and left ventricular ejection fraction in the chronic phase was lower (54% vs. 63%; p < 0.01) in patients with plaque rupture. A multivariate logistic regression analysis revealed that plaque rupture and the proximal lesion site correlated with a left ventricular ejection fraction of <50% in the chronic phase (odds ratios 6.5 and 17.5, respectively; p < 0.05). CONCLUSIONS: Plaque rupture is associated with morphologic characteristics of vulnerable lesions, as well as with larger infarcts and a higher incidence of no-reflow phenomenon, suggesting that plaque embolism contributes to the progression of myocardial damage in patients with anterior AMI.     

The decrease of plaque volume during percutaneous coronary intervention has a negative impact on coronary flow in acute myocardial infarction: a major role of percutaneous coronary intervention-induced embolization

OBJECTIVES: The aim of this study was to evaluate how decreased plaque volume during percutaneous coronary intervention (PCI) affects coronary flow in patients with acute myocardial infarction (AMI). BACKGROUND: Coronary flow after reperfusion therapy is a major determinant of clinical outcomes in patients with AMI. However, little is still known about the changes in coronary flow that appear after PCI in response to the decreased plaque during the procedure. METHODS: The study group comprised 60 patients with AMI who underwent pre- and post-PCI intravascular ultrasound (IVUS). Qualitative and quantitative analyses were performed on all IVUS procedures. External elastic membrane volume (EEMV), lumen volume (LV), and plaque volume (PV) were measured every 1.0 mm to include the lesion and reference segments 3.0 mm proximal and distal to the lesion. The difference between pre- and post-PCI PV was defined as the index of the decrease in plaque volume (DeltaPV). The corrected TIMI frame count (CTFC) was used to evaluate coronary flow after PCI. RESULTS: Plaque volume was decreased at post-PCI IVUS in all 60 patients. Inadequate reflow (CTFC >40) was observed in 13 patients (21.7%). The decrease in PV was significantly larger in patients with inadequate reflow than in those with reflow (49.4 +/- 18.9 vs. 31.7 +/- 15.5 mm(3), p = 0.0010). Also, DeltaPV was significantly correlated with CTFC after PCI (r = 0.415, p = 0.0012). CONCLUSIONS: The decrease in PV during PCI has a negative impact on coronary flow after PCI in patients with AMI. Embolization induced by PCI may occur in all patients with AMI.     

急性与慢性冠状动脉综合征患者电子束CT冠状动脉钙化的比较

目的：比较急性与慢性冠状动脉综合征患电子束CT（EBCT）冠状动脉钙化（CAC）的不同模式。方法：264例患（包括67例SAP、94例UAP和103例AMI）行选择性冠状动脉造影以检测粥样硬化狭窄的程度，行EBCT检查以计算CAC积分，分析各组患CAC积分的差异及其与狭窄程度的关系。结果：（1）SAP组CAC检测阳性率为100％，显高于UAP组的87．23％和AMI组的86．41％（P＜0．05）。（2）SAP组严重钙化的病人和动脉比例显高于UAP组和AMI组（P＜0．05），钙化积分自然对数转换值（In[CS 1])的均数SAP组显高于UAP组和AMI组（P＜0．001）。（3）不同CAC程度在不同狭窄冠状动脉上的分布在SAP组与UAP组有明显差异。（4）AMI组梗死相关动脉多数无钙化或仅有轻度钙化，钙化积分显低于非梗死相关动脉。结论：应用电子束CT研究显示，急性与慢性冠状动脉综合征患存在不同的冠状动脉钙化模式，此点有助于理解这两类冠心病之间在临床和病理方面的差异。     

Predicting angiographic distal embolization following percutaneous coronary intervention in patients with acute myocardial infarction

The aim of this study was to investigate the relation between lesion morphology identified by intravascular ultrasound (IVUS) before intervention and angiographic distal embolization after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). PCI for AMI has already been established as beneficial therapy, although some complications remain unresolved. Distal embolization is 1 of the important complications of PCI. Recently, some new devices have been developed for the prevention of distal embolization. However, few studies exist that look into the relation between lesion morphology and distal embolization. IVUS was performed safely in 140 consecutive patients with AMI before coronary intervention. No patient received thrombolytic therapy. From the incidence of angiographic distal embolization, patients were divided into 2 groups--an embolization group and a nonembolization group--and clinical background, IVUS, and angiographic information were evaluated. Distal embolization was observed in 12 patients (9%). Peak creatine kinase levels (3,877 +/- 2,285 vs 2,293 +/- 1,792 IU/L, p <0.05) and the incidence of angiographic thrombus (25% vs 5%, p <0.05) and intracoronary mobile mass detected by IVUS (75% vs 16%, p <0.001) were higher for patients in the embolization group. From the multivariate logistic regression analysis, only an intracoronary mobile mass detected by IVUS emerged as a predictor of distal embolization (odds ratio 53, 95% confidence interval 2.7 to 1,040, p <0.01). Patients with an intracoronary mobile mass detected by IVUS are prone to distal embolization after PCI and larger infarction. IVUS imaging before PCI may be useful for determining which patients need a distal protection device.     

Out-of-hospital ventricular fibrillation in patients with acute myocardial infarction: coronary angiographic determinants

OBJECTIVES: The study intended to compare the acute coronary anatomy of patients with acute myocardial infarction (AMI) complicated by out-of-hospital ventricular fibrillation (VF) versus patients with AMI without this complication. BACKGROUND: More than half of the deaths associated with AMI occur out of the hospital and within 1 h of symptom onset. The angiographic determinants of out-of-hospital VF in patients with AMI have not been investigated in detail. METHODS: Acute coronary angiographic findings of 72 consecutive patients with AMI complicated by out-of-hospital VF were compared with findings from 144 matched patients with AMI without this complication. RESULTS: Patients with an acute occlusion of the left anterior descending coronary artery (LAD) or left circumflex coronary artery (LCx) had a higher risk for out-of-hospital VF compared with patients with an acute occlusion of the right coronary artery (RCA) (odds ratio and 95% confidence interval, respectively, 4.82 [2.35 to 9.92] and 4.92 [2.34 to 10.39]). With regard to extent of coronary artery disease (CAD), the location of the culprit lesion in the coronary arteries (proximal vs. mid or distal), the flow in the infarct related artery (IRA), the presence or absence of collaterals to the IRA and chronic occlusions, there were no differences between the two groups. CONCLUSIONS: Acute myocardial infarction due to occlusion in the left coronary artery (LCA) is associated with greater risk for out-of-hospital VF compared to the RCA. The location of occlusion within LCA (LAD, LCx, proximal or distal), amount of myocardium at risk for necrosis and extent of CAD are not related to out-of-hospital VF.     

Differentiation between patients with takotsubo cardiomyopathy and those with anterior acute myocardial infarction.

BACKGROUND: There has not been a comparison of the electrocardiographic (ECG) finding of ST-segment elevation in the precordial leads in patients with takotsubo cardiomyopathy (TC) and those with anterior acute myocardial infarction (AMI), with regard to the location of the culprit lesion. METHODS AND RESULTS: The present study evaluated 18 patients with TC, and 85 with anterior AMI who were divided into 3 groups: group A had the culprit lesion proximal to both the first septal branch (S1) and the first diagonal branch (D1), group B had the culprit lesion proximal to either S1 or D1, and group C had the culprit lesion distal to both S1 and D1. In patients with TC, reciprocal ST-segment depression in the inferior leads was observed less frequently than in patients in groups A (p<0.0001) and B (p=0.0002), and abnormal Q waves and ST-segment elevation in the inferior leads were observed more frequently than in group A (p=0.0007, p=0.0057, respectively). The ECG findings in TC did not differ from those in group C. CONCLUSION: Electrocardiographic findings may differentiate TC from AMI with a proximal lesion of left anterior descending coronary artery, but not those with distal lesions.     

Intravascular ultrasound assessment of remodelling and reference segment plaque burden in type-2 diabetic patients.

AIMS: Intravascular ultrasound (IVUS) assesses arterial remodelling by comparing the lesion external elastic membrane (EEM) with the reference segments; however, reference segments are rarely disease-free. The aim was to assess lesion and reference segment remodelling and plaque burden in patients with type-2 diabetes mellitus. METHODS AND RESULTS: We used pre-intervention IVUS to study 62 de novo lesions in 43 patients with type-2 diabetes mellitus. The lesion site was the image slice with the smallest lumen cross-sectional area (CSA). The proximal and distal reference segments were the most normal-looking segments within 5 mm proximal and distal to the lesion. Plaque burden was measured as plaque CSA/EEM CSA. The remodelling index was defined as lesion EEM CSA/mean reference EEM CSA. Reference segment plaque burden measured 0.54 +/- 0.09. The majority of lesions (83.9%) had negative remodelling (lesion EEM < reference). Similarly, the slope of the regression line relating EEM to plaque CSA within the lesion was less than the reference substantiating negative remodelling. The reference segment plaque burden correlated inversely with the difference between IVUS lumen and quantitative coronary angiographic artery size [slope = -0.12 (95% CI -0.17 to -0.07); P < 0.001] in all patients with type-2 diabetes mellitus. CONCLUSION: Lesions in type-2 diabetic patients are different from previous reports in non-diabetics. Lesions in type-2 diabetics are characterized by a large reference segment plaque burden and negative lesion site remodelling. These IVUS findings may explain the angiographic appearance of small arteries in diabetic patients.     

细胞间粘附分子-1和C反应蛋白在急性冠脉综合征患者中的表达及临床意义

目的观察不稳定性心绞痛(UAP)和急性心肌梗死(AMI)患者血清可溶性细胞间粘附分子-1(sICAM-1)和超敏C反应蛋白(hs-CRP)水平的变化,探讨炎症标志物与急性冠脉综合征发病的关系及临床意义.方法选择急性冠脉综合征患者56例(包括AMI组26例、UAP组30例),以同期住院的冠状动脉造影检查正常的30例患者作为对照组,进行对比研究.采用酶联免疫吸附测定法测定血清sICAM-1和hs-CRP水平,并记录每例患者狭窄程度＞50%的冠状动脉病变数.结果血清sICAM-1浓度在AMI组明显高于UAP组及对照组,在UAP组明显高于对照组;血清hs-CRP浓度在AMI组明显高于UAP组及对照组,但UAP组与对照组比较无显著差异;直线相关分析显示,血清sICAM-1水平与受累冠状动脉血管病变数相关,而hs-CRP水平与受累冠状动脉血管病变数无相关关系.结论炎症参与了急性冠脉综合征的发病,炎症因子sICAM-1血清水平升高与急性冠脉综合征的发生密切相关,还与动脉粥样硬化的范围和程度相关,可以作为监测急性冠脉综合征病情的指标,而hs-CRP水平升高主要与其稳定性有关.     

A case report of late coronary stent thrombosis manifested as acute myocardial infarction 19 months after stenting

A 63-year-old Japanese man was readmitted to our hospital due to acute broad-anterior myocardial infarction (AMI). The proximal left anterior descending artery (LAD) at the prior stent, which was implanted 19 months earlier and in which no angiographic restenosis was recognized 13 months before the second study, was totally occluded. After crossing a guide wire and balloon angioplasty, angiographic radiolucency was observed at the prior stent, suggesting that AMI was induced by late coronary stent thrombosis. Intravascular ultrasound performed 19 days after the onset of AMI revealed superficial calcification without significant stenosis and an atherosclerotic plaque distal to the stent that was not significantly changed compared to 19 months previously, consistent with the culprit lesion being an intrastent site. AMI may thus be induced by late coronary stent thrombosis during long-term clinical follow-up without clinical symptoms or angiographic restenosis at the second study.     

Effectiveness of excimer laser coronary angioplasty in acute myocardial infarction or in unstable angina pectoris

This study was conducted to evaluate the feasibility, safety, and acute results of percutaneous excimer laser coronary angioplasty (ELCA) in acute coronary syndromes. Fifty-nine patients were treated with ELCA (308 nm), including 33 patients with unstable angina pectoris (UAP) (35 vessels with 39 lesions) and 26 patients with acute myocardial infarction (AMI) (26 vessels with 29 lesions). In each patient the target lesion had a complex morphology. Overall, 71% of the patients had contraindications for pharmacologic thrombolytic agents or glycoprotein IIb/IIIa receptor antagonists. All patients received adjunct balloon dilation followed by stent implantation in 88% of patients with AMI versus 76% of patients with UAP (p = NS). Quantitative angiography was performed at an independent core laboratory; 86% laser success and 100% procedural success was achieved in the AMI group versus 87% laser success and 97% procedural success in the UAP group (p = NS). In the AMI group, the minimal luminal diameter increased from 0.77 +/- 0.56 to 1.44 +/- 0.47 mm after lasing to a final 2.65 +/- 0.47 mm versus 0.77 +/- 0.38 to 1.35 +/- 0.4 mm after lasing to 2.66 +/- 0.5 mm final in the UAP group. A prelaser percent stenosis of 76 +/- 17% for the AMI group versus 70 +/- 16% for the UAP group (p = NS) was decreased after lasing to 52 +/- 16% for the AMI group versus 51 +/- 14% for the UAP group (p = NS) and to a final stenosis of 15 +/- 17% for the AMI group versus 12 +/- 15% for the UAP group (p = NS). A 96% laser-induced reduction of thrombus burden area was achieved in the AMI group versus 97% in the UAP group (p = NS). Preprocedure Thrombolysis In Myocardial Infarction flow of 1.3 +/- 0.9 in the AMI group versus 2.3 +/- 1.2 for the UAP group (p = 0.01) increased to a final flow of 3.0 +/- 0 for the AMI group versus 3.0 +/- 0 for the UAP group (p = NS). There were no deaths, cerebrovascular accident, emergency bypass surgery, acute closure, major perforation or major dissection, distal embolization, or bleeding complications in either group. One patient with AMI had localized perforation (caused by guidewire) without sequelae and 1 patient with UAP had an abnormal increase in creatine kinase levels. All 59 patients survived the laser procedure, improved clinically, and were discharged. Thus, early experience in patients with acute coronary syndromes suggest that percutaneous ELCA is feasible and safe.     

Adaptive remodeling of the infarct-related artery is associated with recurrent ischemic events after thrombolysis in acute myocardial infarction

BACKGROUND: Recurrent ischemic events occur during the hospital stay of 7-32% of patients after successful thrombolytic treatment of acute myocardial infarction (AMI). OBJECTIVE: To define the association between postinfarction angina pectoris and the clinical, angiographic, and intravascular ultrasound (IVUS) parameters of the infarct-related artery for consecutive prospectively included patients. METHODS: Clinical, qualitative, and quantitative angiographic and IVUS data for 64 patients (56 men, aged 53+/-12 years) with thrombolysis of AMI were analyzed. All patients underwent coronary angiography and pre-interventional IVUS measurement electively within 1 month of AMI or at the time of the occurrence of postinfarction angina pectoris. Classification as adaptive or constrictive remodeling was according to whether the cross-sectional area of a vessel was larger or smaller than that of the proximal or distal reference segment. RESULTS: Nineteen of the 64 patients (29.7%) suffered from recurrence of ischemic events (group 1), whereas 45 patients (60.3%, group 2) remained free from symptoms. In univariate analyses, multivessel disease (42 versus 24%, P= 0.0236) and adaptive remodeling (63 versus 24%, P= 0.0032) were found to occur more commonly among patients in group 1. The patients in group 1 exhibited larger total vessel cross-sectional areas than did the patients in group 2 (17.5+/-4.2 versus 14.9+/-6.1 mm2, P = 0.0556). In multivariate regression analysis, adaptive remodeling proved to be a significant predictor (P = 0.0145) of the recurrence of ischemic events after thrombolysis of AMI. CONCLUSIONS: Adaptive remodeling of the infarct-related artery is associated with early postinfarction angina pectoris after thrombolysis of AMI.     

Interventricular septal motion in acute myocardial infarction with proximal and distal left anterior descending coronary lesions

To evaluate the ability of echocardiography to detect and localize lesions of the proximal and distal left anterior descending (LAD) coronary arteries, the systolic excursion of the left side of the septum and the ratio of septal to posterior wall excursion (IVS/PW) were measured in 26 patients with acute myocardial infarction (AMI) and nine normal control subjects. The patients with proximal LAD lesions had septal wall excursions of less than 3 mm, whereas in those with distal LAD lesions septal wall excursions were more than 3 mm. All patients with proximal LAD lesions showed an IVS/PW ratio of less than 0.4, but in those with distal LAD lesions the ratio was 0.4 or greater. We conclude that reduced or absent interventricular septal motion in anterior AMI suggests an LAD lesion, and a septal excursion of less than 3 mm suggests involvement of the proximal LAD artery, whereas septal excursion of 3 mm or more indicates involvement of the distal LAD artery.     

Feasibility of intravascular ultrasound studies: Predictors of imaging success before coronary interventions

Background: Intravascular ultrasound (IVUS) is currently used to study lesions during transcatheter coronary therapy. However, before dilation some lesions cannot be reached or crossed with the imaging catheter. Hypothesis: This study seeks to elucidate which factors determine the feasibility of IVUS examination before coronary interventions. Methods: Accordingly, 100 consecutive patients undergoing IVUS examination before coronary angioplasty were prospectively studied. The clinical and angiographic characteristics of 77 patients with a successful IVUS study (Group A) were compared with those of 23 patients in whom IVUS was attempted but the target lesion could not be interrogated (Group B). The echogenic characteristics of the target lesion [before (n = 77) or after intervention (in 18 patients in Group B)] were also studied. Results: Patients in Group B were significantly older (62 ± 7 vs. 57 ± 10 years, p < 0.05) and more frequently had stable angina [8 (35%) vs. 9 (11%), p < 0.05]. The distribution of lesions within the coronary tree and angiographic lesion characteristics including length, eccentricity, calcification, bend location, and the American College of Cardiology/American Heart Association classification were similar in both groups. However, proximal tortuosities (>45° at end diastole) were more frequently found in Group B [20 (87%) vs. 47 (61%), p < 0.05]. In addition, by quantitative angiography, patients in Group B had smaller arteries (reference diameter 2.8 ± 0.4 vs. 3.1 ± 0.4 mm, p < 0.05) and more severe lesions (minimal lumen diameter 0.46 ± 0.24 vs. 0.65 ± 0.34 mm, p < 0.05). On IVUS, calcified lesions were more frequently visualized in Group B (61 vs. 38%, p < 0.05). On multivariate analysis, catheter size, baseline minimal lumen diameter, angiographic proximal tortuosities, and lesion calcification on imaging were independent predictors of the feasibility of IVUS studies. Conclusions: Unsuccessful IVUS studies before intervention occur more frequently (1) in vessels with proximal tortuosities or severe lumen narrowing, (2) in lesions that are calcified on IVUS, and (3) when large imaging catheters are used.     

不稳定型心绞痛患者的血管内超声分析

目的:应用血管内超声(IVUS)探讨不稳定型心绞痛(UAP)患者的斑块形态学特点。方法:经冠状动脉造影和IVUS检查的冠心病患者57例,其中稳定型心绞痛(SAP)21例,UAP 36例,根据斑块回声的强度,将斑块分为软斑块、纤维斑块、钙化斑块、混合斑块和斑块破裂等,分析比较UAP和SAP患者的斑块的形态学特点。结果:IVUS发现软斑块的比例在SAP和UAP患者中分别为47.6%和75.0%,纤维斑块的比例分别为52.4%和25.0%,斑块破裂分别为0和30.6%,钙化斑块分别为52.4%和19.4%(均P<0.05)。结论:IVUS显示UAP的斑块形态学特点主要表现为软斑块和斑块破裂。     

左主干冠状动脉病变的血管内超声研究

目的 血管内超声评价非严蕈钙化性左主干病变的形态特点,探讨开口和非开口部位形成狭窄的不同机制.方法 2004年10月至2007年10月,共入选造影确诊或可疑的狭窄病变并行血管内超声检查的153例(开口47例,非开口106例)非严重钙化性左主干病变,定性和定量分析血管内超声图像;负性重构定义为重构指数＜0.95.结果 左主干参考节段平均管腔直径和血管(外弹力膜)直径为(4.1±0.8)mm和(5.3士0.8)mm.开口病变的纤维性、钙化性和软斑块分别为70.2%、19.2%和8.5%,而非开口病变为35.8%、43.4%和3.8%,两者差异有统计学意义(P=0.01).总体来说,31.1%病例的最小管腔面积＜6 mm2,其中开口组29.5%,非开口组31.9%(P=0.87).最小管腔面积在两组相似,但非开口组的斑块面积[(13.3±5.4)mm2比(10.8±4.5)mm2,P=0.007]和斑块负荷(61.9%±14.5%比54.8%±15.9%,P=0.020)均显著大于开口组,斑块负荷＞50%的比例更高(84.8%比61.3%,P=0.002).开口病变的重构系数显著低于非开口病变(0.9±0.2比1.0.±0.2,P=0.000),而且负性重构更多见(74.5%和34.9%,P=0.000).logistic回归分析发现,病变部位(OR=4.9,P=0.004)、斑块面积(OR=1.2,P=0.01)和斑块负荷(OR=0.003,P=0.000)是左主干发生重构的独立预测因素.结论 负性重构现象在左主干开口病变中更常见,可能是其狭窄形成的机制之一.狭窄程度不确定的冠状动脉左主干病变需要血管内超声精确评价.     

冠状动脉二支主干堵塞行介入治疗完全血运重建

目的：本研究探讨对16例冠状动脉二支主干堵塞者采用分步和分次冠状动脉介入治疗术（PCI）完全血运重建的有效性和安全性。方法：（1）对5例急性心肌梗死（AMI）,采取一次性分步直接PCI术完成血运重建;（2）对11例不稳定型心绞痛（UAP）,采取多次性分步PCI术达到完全血运重建,首先解除本次发病罪犯血管的堵塞;（3）恰当使用XB导引导管、Crossit硬导丝和Maverick球囊以及主动脉内球囊反搏（IABP）支持。结果：（1）5例AMI二支堵塞冠状动脉均成功植入支架,并首先使左前降支（LAD）再通。（2）11例UAP中21／22支冠状动脉二支主干堵塞处经球囊预扩张后,均成功植入支架,所有堵塞冠脉均获得TIMI-Ⅲ级血流。（3）16例患者术后心电图显示心肌缺血明显改善,心脏超声显示左室射血分数较术前明显改善,由（42±34）％升至（51±44）％。经过平均18个月随访,患者生活质量明显提高,未发生严重心血管事件。结论：冠状动脉二支主干堵塞者行PCI术完全血运重建安全可行;对AMI者优先开通LAD的一次性PCI术安全高效;对慢性堵塞UAP者,优先开通近期罪犯病变的多次性PCI术既可达到完全血运重建,又符合临床实际。