Distinction of non-ischemia inducing versus ischemia inducing coronary stenosis by fluorescent cardiac imaging

Intraoperative fluorescent cardiac imaging (FCI) can quantitatively assess myocardial perfusion abnormalities produced by graded flow-limiting coronary stenosis (FLS), but there are no data to distinguish FLS from non flow-limiting stenosis (NFLS) to determine their functional significance. The aim of the study was to evaluate whether non-ischemia inducing NFLS can be quantified and differentiated from FLS by FCI technology. Data are compared to gold standard fluorescent microspheres (FM). 11 domestic pigs of either sex underwent sternotomy. Left anterior descending coronary artery blood-flow was recorded by transit-time flow measurements. After baseline and Adenosine-induced hyperemia, two stenosis of low severity (50 and 90 % NFLS) were produced, followed by FLS (50 %) and total vessel occlusion. Time-dependent fluorescence intensity curves were recorded by FCI. Slope of fluorescence intensity (SFI) and background-subtracted peak fluorescence (BSFI) intensity were calculated and data compared to myocardial blood flow measurements using FM. All NFLS and FLS reduced myocardial perfusion as quantified by FCI showing decreased normalized BSFI and SFI (P < 0.001). Box-plot analysis showed significant difference between NFLS (50 and 90 %) and FLS (50 %) assessed by BSFI (P < 0.001) and SFI (P < 0.001). In each animal, a linear correlation between FM-derived myocardial blood flow and FCI-derived BSFI (r = 0.936, P < 0.001) or SFI (r = 0.942, P < 0.001) was observed during baseline, hyperemia, graded NFLS, and FLS. Both, BSFI (r = 0.789, P < 0.001) and SFI (r = 0.802, P < 0.001) significantly correlated with transit-time flow measurements. FCI quantitative technology is capable of distinguishing between non-ischemia inducing NFLS and ischemia inducing FLS showing a good correlation compared to fluorescent microspheres.     

Assessment of coronary stenoses of graded severity by myocardial contrast echocardiography.

BACKGROUND: Myocardial contrast echocardiography (MCE) has potential value in the assessment and quantitation of myocardial perfusion defects. However, the severity of stenosis detectable by MCE and its diagnostic accuracy remain undefined. Thus, we produced coronary stenoses of variable severity and quantified their effect on MCE. METHODS AND RESULTS: Three grades of left anterior descending (LAD) obstructions were produced in 7 open-chest swine. The stenoses were nonflow-limiting at rest, but decreased coronary hyperemia by 31.3% +/- 4.7%, 69.9% +/- 5.3% and 98.9% +/- 1.1%, respectively. Regional myocardial blood flow (RBF) was measured with fluorescent microspheres and was expressed as the ratio of LAD and control (LCx) beds. MCE was performed with 0.3 mg/kg intravenous AF0150 during ECG-gated harmonic imaging in short-axis view. Background-subtracted peak intensity (PI) was expressed as the ratio of LAD/LCx beds. Both RBF and PI ratios progressively decreased with increasing grades of stenosis. MCE showed a significant correlation with RBF (r = 0.74; P <.0001). Ratios of both PI and RBF differed significantly from baseline when coronary hyperemia was reduced more than 50%. An LAD/LCx ratio less than 0.6 by MCE yielded 61% and 83% sensitivity and 85% and 76% specificity with stenosis that reduced coronary hyperemia more than 50% and more than 75%, respectively. CONCLUSION: MCE with intravenous AF0150 during vasodilation correctly depicted the progressive reduction of flow ratios produced by graded coronary stenoses. A significant reduction of PI ratio was observed with stenosis causing more than 50% reduction of coronary hyperemia. An MCE ratio in stenosed/control beds could be selected, which exhibited good sensitivity and specificity in the identification of coronary stenosis.     

Discordance between dipyridamole stress technetium-99m tetrofosmin single photon emission computed tomography and coronary angiography in patients with Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis syndrome of unknown etiology that mainly affects the coronary arteries. The purpose of this study was to assess the agreement between dipyridamole stress technetium-99m tetrofosmin (Tc-TF) myocardial perfusion single photon emission computed tomography (SPECT) and coronary angiography in these patients. Twenty-nine children with KD were included in this study. All of the 29 children also received dipyridamole stress Tc-TF myocardial perfusion SPECT within 1 month of their coronary angiographic studies. The results showed that (1) 89.7% of children had negative coronary angiographic findings without significant coronary stenoses, and 10.3% of children had positive coronary angiographic findings with significant coronary stenosis; (2) 44.8% of children had negative Tc-TF myocardial perfusion SPECT findings without abnormal myocardial perfusion, and 55.2% of children had positive Tc-TF myocardial perfusion SPECT findings with abnormal myocardial perfusion; (3) 44.8% of children had both normal coronary angiographic and Tc-TF myocardial perfusion SPECT findings, and 10.3% of children had both abnormal coronary angiographic and Tc-TF myocardial perfusion SPECT findings; and (4) There was no significant agreement between coronary angiographic and Tc-TF myocardial perfusion SPECT findings. We concluded that poor agreement exists between coronary angiographic and Tc-TF myocardial perfusion SPECT findings with coronary stenoses and abnormal myocardial perfusion in children with KD.     

CT和MRI在冠状动脉疾病诊断中的应用比较

目的比较心脏计算机断层扫描(CT)和心脏磁共振成像(MRI)在冠状动脉疾病的诊断的应用方法。方法 2008年2月到2010年2月我们前瞻性的连续选择了94例已知或者疑似CAD的患者,进行MRI心肌灌注、传统的冠状动脉造影、前瞻性ECG-门控的冠脉CTA分析,并比较了MRI心肌灌注和CA、前瞻性ECG-门控冠脉CTA加MRI心肌灌注和CA;评估了血流动力学相关狭窄。结果 MRI心肌灌注揭示了60/94(63.8%)的人具有心肌缺损(灌注缺损或梗阻)。CA揭示了94例病人中有66例冠状动脉中有150例大于50%直径的狭窄。平均每名患者的有效辐射剂量为2.5±1.1mSv。检测冠状动脉狭窄大于50%,在CA的敏感性,特异性,NPV,PPV和准确率低于MRI心肌灌注以及冠脉CTA加MRI心肌灌注。其中1例病人在CD伴随着MRI心肌灌注的LAD灌注缺损,在冠脉CTA被判定为没有明显狭窄。结论在诊断血流动力学相关的CAD,冠状动脉CTA可能取代CA。     

Relation between geometric dimensions of coronary artery stenoses and myocardial perfusion reserve in man.

To determine the relation between stenosis anatomy and perfusion in man, 31 patients had quantitative coronary arteriography and positron imaging (PET) with Rb-82 or N-13 ammonia at rest and after dipyridamole-handgrip stress. 10 patients were also studied after angioplasty (total stenoses = 41). Percent narrowing and absolute cross-sectional luminal area were related through a quadratic function to myocardial perfusion reserve determined with PET. Arteriographically determined coronary flow reserve was linearly related to relative myocardial perfusion reserve as expected, based on the derivation of equations for stenosis flow reserve. All of the correlations had considerable scatter, indicating that no single measurement derived by coronary arteriography was a good indicator of perfusion reserve by PET in individual patients. This study provides the relation between all anatomic dimensions of coronary artery stenoses and myocardial perfusion reserve in man, and suggests that PET indicates the functional significance of coronary artery stenoses for clinical purposes.     

The role of magnetic resonance in the evaluation of functional results after CABG/PTCA

Magnetic resonance imaging (MRI) is a non-invasive modality which can be used for direct visualization of coronary artery bypass grafts. Spin-echo and gradient-echo (cine-MRI) techniques are now available on standard MR machines and provide information on graft morphology and graft patency with a 90% accuracy. By combining the standard techniques with MR phase velocity mapping, the flow rate in the graft can be measured, thereby offering a unique non-invasive assessment of the graft function. Newer techniques include MR coronary angiography, pharmacologically induced stress MRI, ultrafast MRI of the first-pass (perfusion) of a paramagnetic contrast agent through the myocardium, and³¹P MR spectroscopy of high-energy phosphate metabolism of the myocardium. All of these may develop into valuable diagnostic tools for the assessment of functional results after CABG or PTCA, but still require clinical validation. At present, MRI is a useful screening procedure for assessment of graft patency and function in post-operative pain syndromes and in late graft occlusion or stenosis.     

Effect of antegrade graft cardioplegia combined with passive graft perfusion in on-pump coronary artery bypass grafting

Patients undergoing on-pump coronary artery bypass graft (CABG) with proximal graft anastomosis were randomly divided into groups that received antegrade cardioplegic infusion only via the aortic root (group A) or antegrade cardioplegic infusion via the aortic root and additional cardioplegia via vein or free arterial grafts after completion of each distal anastomosis (group B). The group B patients also received bypass graft perfusion with warm arterial blood just after removal of the cross-clamp until the proximal graft anastomosis was completed. The need for defibrillation and inotropic support during separation from cardiopulmonary bypass (CPB), and total CPB time were significantly lower in group B than in group A. Group B also had significantly lower peak cardiac troponin I levels 12 h after operation compared with group A and this was more pronounced in subgroups with severe right coronary artery stenosis and poor left ventricular ejection fraction than in the whole population. It is concluded that antegrade graft cardioplegia and graft perfusion with warm blood during proximal graft anastomosis may improve myocardial protection.     

Adenosine myocardial contrast echo in intermediate severity coronary stenoses: a prospective two-center study

Background We sought to evaluate the role of adenosine myocardial contrast echocardiography (MCE) for the determination of functional relevance of coronary stenoses with intermediate angiographic severity and compared the results to single photon imaging (SPECT). We hypothezised that sole assessment of myocardial blood volume changes during adenosine on MCE would indicate functional stensosis relevance when accompanied by increased myocardial oxygen consumption (MVO2). Methods Fifty-seven patients with ≥1 coronary stenosis underwent adenosine MCE (ultraharmonic imaging) and exercise SPECT. On MCE, myocardial blood volume was assessed and constant or increased myocardial opacification during adenosine coupled with increased MVO2 was defined as normal and decreased opacification as abnormal. Results Rate–pressure product significantly increased during adenosine in all patients due to reflex tachycardia following mild hypotension, indicative of increased MVO2. Concordance between MCE and SPECT for the detection of reversible myocardial perfusion defects was 89% (κ = 0.83). Comparison of regions between rest and during adenosine as opposed to comparison to remote regions of the same stage was important for accurate assessment because concordance betweenn MCE and SPECT was less on separate assessment at rest (73%, κ = 0.40) compared to stress (91%, κ = 0.81, P < 0.05) mainly due to territories scored normal on SPECT and abnormal on MCE. Conclusions Assessment of myocardial blood volume changes during adenosine using MCE can be used for the determination of the functional relevance of coronary stenoses of intermediate angiographic severity if MVO2 is increased during adenosine.     

Proximal culprit lesion and coronary artery occlusion independently predict the risk of microvascular obstruction in acute myocardial infarction

Microvascular obstruction (MO) and coronary flow have been independently described to have a high prognostic impact after acute myocardial infarction (AMI). Their interdependence has not been precisely elucidated, so far. Aim of this study was to investigate the impact of coronary flow on the occurrence of MO in patients with AMI. 336 patients with revascularized AMI were examined by cardiac magnetic resonance imaging. Patients were categorised into two groups based on the presence of MO. Procedural characteristics and marker of infarct size were analyzed. MO was present in 110 (33?%) and absent in 226 (67?%) patients. Both groups differed significantly regarding pre- and post-interventional thrombolysis in myocardial infarction (TIMI) flow. After multivariable regression analysis pre-interventional TIMI-flow 0, proximal culprit lesion, post-interventional TIMI-flow <III and creatine-kinase–myocardial band (CK-MB) remained strong independent predictors for MO. Odds ratios for pre-interventional TIMI-flow 0 were 2.31 (95?% CI 1.04–5.11, P?=?0.034); for proximal culprit lesion 11.94 (95?% CI 5.70–25.01, P?<?0.001); for post-interventional TIMI-flow III 0.28 (95?% CI 0.10–0.74, P?=?0.010) and for CK-MB 1.50 (95?% CI 1.24–1.82, P?<?0.001). Pre-interventional proximal coronary artery occlusion (TIMI 0) and insufficient post-interventional coronary reperfusion (TIMI-flow? <III) have a high impact on the occurrence of MO in AMI.     

冠状动脉桥血管的多层螺旋CT和造影评价

目的:评价多层螺旋CT在显示冠状动脉桥血管中的临床应用价值。方法:21例冠状动脉血管旁路移植术后患者行多层螺旋CT血管成像及常规造影检查,分析CT诊断桥血管通畅性和狭窄的可靠性。结果:多层螺旋CT血管成像成功检测出21例患者共45支桥血管,15支桥血管闭塞,30支桥血管通畅,10支共16处狭窄,5支桥血管明显狭窄(>50%)8处,5支桥血管显示轻度狭窄(<50%)病变8处,MSCT评价桥血管闭塞和明显狭窄和导管造影完全符合。结论:多层螺旋CT尤其是64层CT能够准确地评价冠状动脉桥血管及吻合口的通畅性和狭窄情况,可以作为临床上对冠状动脉桥血管可疑病变的一种常规的无创性检查手段。     

自制心肌超声造影定量分析软件的设计与评价

目的评价自制心肌超声造影(MCE)图像定量分析软件对心肌灌注研究的可行性。方法根据阻断和再灌注冠状动脉时间不同,家兔被分为两组:阻断15min再灌注30min(Ⅰ组)和阻断120min再灌注60min(Ⅱ组)。分别于基础状态、冠状动脉阻断时和再灌注后行MCE,应用基于淘汰粒子群优化(EPSO)聚类算法的自制计算机图像定量分析软件对造影图像进行自动处理,获得多个心肌灌注定量参数。结果 (1)阻断时,Ⅰ组与Ⅱ组危险心肌的标化CI值均明显减低,与基础状态比较差异有统计学意义(t=5.104和t=4.327,P0.01)。再灌注后,Ⅰ组危险心肌标化CI值比阻断时增高(t=2.933,P0.01),与基础状态时相比仍减低(t=2.653,P0.01),Ⅱ组危险心肌标化CI值与阻断时相比差异无统计学意义(P0.05);(2)Ⅱ组危险心肌红色编码区和TTC中梗死心肌面积分别为(21.4±12.3)%和(18.0±9.5)%,且与TTC结果呈正相关(r=0.89,P0.01);(3)阻断时,危险心肌节段直方图呈偏态分布,再灌注后,Ⅰ组危险心肌基本恢复至正态分布,而Ⅱ组危险心肌仍呈偏态分布。结论基于淘汰粒子群优化聚类算法的心肌超声图像分析软件在定量评价心肌微灌注和识别灌注异常方面具有较好的可行性和较高的应用价值。     

Incidence and predictors of target vessel revascularization after sirolimus-eluting stent treatment for proximal left anterior descending artery stenoses among 2274 patients fromthe prospectivemulticenter German Cypher Stent Registry

BACKGROUND: Involvement of the proximal LAD is considered an indication for coronary artery bypass graft (CABG) surgery due to the high restenosis rates associated with this location after percutaneous coronary interventions (PCI). This seems to be different, however, when using sirolimus-eluting stents, a finding if proven to be true could have a major impact on clinical decision making regarding the optimal revascularization strategy for these patients. METHODS: We analyzed 2274 patients treated for proximal LAD stenoses using SES from the German Cypher Stent Registry. The incidence of TVR and other major clinical adverse events were determined and independent predictors of TVR were specified using a multiple logistic regression model. RESULTS: Event-free survival was achieved in 89.5% of patients. TVR was performed in 179 patients (7.9%) and the combined incidence of all cause death, myocardial infarction and TVR was 10.5% (231 patients). Independent predictors of TVR were multivessel disease (OR 1.74, 95% CI 1.16-2.62, p = 0.008), stent diameter < or = 2.75 mm (OR 1.61, 95% CI 1.10-2.40, p = 0.02) and the administration of GP IIb/ IIIa antagonists (OR 1.60, 95% CI 1.05-2.60, p = 0.03). TVR rate was as high as 11.2% for 2.5 mm SES and as low as 4.0% for 3.5 mm SES (p < 0.001 for trend test). CONCLUSION: TVR among patients treated with SES for proximal LAD stenoses is low and is related in part to operator dependent factors. Treatment with SES should be considered as an effective treatment for these patients.     

Staccato left anterior descending artery occlusion: a recognizable subset of unstable angina

Twenty-four of 96 patients with unstable angina exhibited transient ST-T abnormalities in anterior electrocardiographic leads at rest combined with severe subtotal stenosis (80% to 95% narrowing) of the proximal left anterior descending artery (LAD). This entity is termed staccato LAD occlusion to signify the probable pathophysiology responsible for the patients' repeated episodes of ischemic cardiac angina. Although staccato LAD occlusion represents a minority of patients hospitalized with unstable angina, it includes most who suffer cardiac complications. Among patients treated medically, 10 of 16 with staccato LAD occlusion developed anterior myocardial infarction, whereas cardiac complications occurred in only three of the remaining 50 patients with unstable angina during the 4-month follow-up period (p less than 0.001). Medical treatment of staccato LAD occlusion should be directed primarily against coronary occlusion. Considering the high risk of myocardial infarction, until reliable methods for preventing the threatened occlusion are demonstrated, urgent coronary bypass surgery seems warranted for these patients.     

Prediction of clinical outcome by myocardial CT perfusion in patients with low-risk unstable angina pectoris

The prognostic implications of myocardial computed tomography perfusion (CTP) analyses are unknown. In this sub-study to the CATCH-trial we evaluate the ability of adenosine stress CTP findings to predict mid-term major adverse cardiac events (MACE). In 240 patients with acute-onset chest pain, yet normal electrocardiograms and troponins, a clinically blinded adenosine stress CTP scan was performed in addition to conventional diagnostic evaluation. A reversible perfusion defect (PD) was found in 38 patients (16?%) and during a median follow-up of 19 months (range 12–22 months) 25 patients (10?%) suffered a MACE (cardiac death, non-fatal myocardial infarction and revascularizations). Accuracy for the prediction of MACE expressed as the area under curve (AUC) on receiver-operating characteristic curves was 0.88 (0.83–0.92) for visual assessment of a PD and 0.80 (0.73–0.85) for stress TPR (transmural perfusion ratio). After adjustment for the pretest probability of obstructive coronary artery disease, both detection of a PD and stress TPR were significantly associated with MACE with an adjusted hazard ratio of 39 (95?% confidence interval 11–134), p?<?0.0001, for visual interpretation and 0.99 (0.98–0.99) for stress TPR, p?<?0.0001. Patients with a PD volume covering >10?% of the LV myocardium had a worse prognosis compared to patients with a PD covering <10?% of the LV myocardium, p?=?0.0002. The optimal cut-off value of the myocardial PD extent to predict MACE was 5.3?% of the left ventricle [sensitivity 84?% (64–96), specificity 95?% (91–97)]. Myocardial CT perfusion parameters predict mid-term clinical outcome in patients with recent acute-onset chest pain.     

64层螺旋CT在评价冠状动脉桥血管中的价值

目的探讨64层螺旋CT在诊断冠状动脉桥血管的临床价值。方法对21例冠状动脉搭桥术的患者行64层螺旋CT心、胸部血管造影检查。对所有扫描原始数据行冠状、矢状MPR、曲面重建(CPR)以及VR、MIP重建。由两位有经验的放射科医生对所有图像进行观察,对桥血管狭窄进行诊断,并评价其狭窄程度。8例CT诊断桥血管重度狭窄(管腔狭窄>75%)或闭塞的患者同时行选择性血管造影检查。结果21例患者均可清晰地显示冠状动脉各主要分支,并能清晰地显示其斑块和管腔的狭窄。21例患者经螺旋CT心、胸部血管造影检查,可清晰显示52条桥血管,其中13条桥血管出现再狭窄(10条为大隐静脉桥血管,3条为乳内动脉桥血管),狭窄部位均位于桥血管吻合口处;重度狭窄7条,闭塞1条,此8条桥血管均与选择性血管的结果相吻合,CT评价冠状动脉桥血管重度狭窄的准确性为100%。结论64层螺旋CT心、胸血管造影检查不但能显示冠状动脉桥血管,而且能清晰地显示原始的冠状动脉及冠状动脉与桥血管的吻合口,是评价冠状动脉桥血管的一种有效的可靠的检查方法。     

Segmental analysis of thallium 201 myocardial perfusion scintigraphy: its value in a community hospital

In a community hospital, we correlated results of thallium 201 myocardial scintigraphy with coronary arteriographic data in 79 patients. Scintigraphy was 92% sensitive and 85% specific in detecting coronary artery disease. There were no false-negative scintigrams in patients with double or triple vessel disease. The most important factors determining sensitivity of the method in detecting individual coronary stenoses were (1) location of the stenosis in the coronary tree, (2) number of vessels involved, and (3) degree of obstruction. Higher prevalence of perfusion defects in areas of 90% to 99% stenosis as compared with 50% to 89% lesions was of borderline statistical significance (86% vs 59%; P = .06). Myocardial perfusion scintigraphy was unable to predict the number of significantly narrowed coronary vessels. Predictive value of a perfusion defect for a significant coronary stenosis was 87% for anterior, 88% for septal, 90% for lateral, 89% for posterior, and 78% for inferior segment. We conclude that segmental analysis of myocardial scintigrams may be of value in a community hospital.     

Tl-201 myocardial SPECT in silent myocardial ischemia and angiographically proven coronary heart disease

Silent myocardial ischemia is defined as true myocardial ischemia without angina pectoris in patients with angiographically detected coronary artery disease. In this study 52 patients (46 male, 8 female: mean age 53 years) with a pathological exercise test but no symptoms were investigated. They showed stenosis of 75% or more of the diameter in at least one coronary segment on angiography. Prior to or after catheterization (within 14 days) Tl-201 SPECT was done and evaluated independently of angiography. A clear correlation between angiographically confirmed stenosis and reversible perfusion defects with Tl-201 SPECT was established (62 out of 76 lesions). Furthermore, there was a significant relation between angiographically detected subtotal or total occlusions of coronary vessels and irreversible perfusion defects using Tl-201 SPECT (35 in 44 lesions) (p less than 0.001). In patients with ST depression but without angina pectoris during the exercise test, the Tl-201 SPECT is highly suited to determine the hemodynamic effect of coronary stenoses.     

Utility of stress perfusion-cardiac magnetic resonance in follow-up of patients undergoing percutaneous coronary interventions of the left main coronary artery

To assess the accuracy of cardiac magnetic resonance (CMR) for the diagnosis of angiographic stenosis after percutaneous coronary intervention (PCI) of left main coronary artery (LMCA). Patients undergone in the last year PCI of unprotected LMCA and scheduled for conventional X-ray coronary angiography (CXA) were evaluated with stress perfusion CMR within 2 weeks before CXA. Main contraindications to CMR were exclusion criteria. Stress perfusion CMR was performed to follow a bolus of contrast Gadobutrol after 3 min of adenosine infusion. Between the 50 patients enrolled, only 1 did not finish the CMR protocol and 49 patients with median age 71 (65–75) years (38 male, 11 female) were analyzed. Between 784 coronary angiographic segments evaluated we found 75 stenosis or occlusions (prevalence 9.5%), but only 13 stenosis or occlusions in proximal segments (prevalence 6.6%). Patients with coronary stenosis (n?=?12, 24%) showed a significantly (p?=?0.002) higher prevalence of diabetes (7 of 12, 58%). At CMR examination, late gadolinium enhancement was present in 25 (51%), reversible perfusion defects in 12 (24%), and fixed perfusion defects in 6 subjects (12%). The only patient with LMCA restenosis resulted positive at perfusion CMR. The accuracy of stress perfusion CMR in diagnosis of coronary stenosis was higher when the analysis was performed only in proximal coronary arteries (95%, CI 86–99) compared to overall vessels (84%, CI 70–92). Stress perfusion CMR could strongly reduce the need for elective CXA in follow up of LMCA PCI and should be validated in further multicenter prospective studies.     

Combined coronary and perfusion cardiovascular magnetic resonance for the assessment of coronary artery stenosis.

The purpose of this study was to evaluate the feasibility and accuracy of combined coronary and perfusion cardiovascular magnetic resonance (CMR) in the assessment of coronary artery stenosis. Thirty-five consecutive patients (27 men, eight women, age range 34-81 years), undergoing cardiac catheterization, were assessed with 3D coronary CMR and rest-stress perfusion CMR. Significant coronary stenosis was determined by vessel narrowing or signal loss with coronary CMR, and by abnormal contrast enhancement with perfusion CMR. Coronary artery diameter stenosis greater than 50% was considered significant with conventional cardiac catheterization. Seventeen patients had significant coronary artery disease, and in these there were 35 significant stenoses on cardiac catheterization. All left main stem arteries were normal on both cardiac catheterization and coronary CMR. For the diagnosis of coronary artery stenosis, coronary CMR had a sensitivity of 92% for the left anterior descending artery (LAD), 79% for the right coronary artery (RCA), but only 13% for the circumflex coronary artery (LCX). Perfusion CMR had corresponding sensitivities of 69%, 86%, and 63%, respectively. For all arteries the accuracies for coronary and perfusion CMR were 67% and 72%, respectively. Combining coronary and perfusion CMR improved the accuracy to 77%. These data demonstrate that in patients with suspected coronary artery disease, combined coronary and perfusion CMR is feasible, increases the accuracy of detection of significant coronary stenosis, and offers the possibility of combined anatomical and hemodynamic assessment of coronary artery stenosis.     

Repeat myocardial revascularization for uncontrollable angina after occlusion of prior aortocoronary bypass.

Twelve patients at Emory University Hospital have had repeat myocardial revascularization for recurrent, uncontrollable, disabling angina pectoris after previous coronary artery bypass grafts. The interval betweeen initial bypass procedure and reoperation ranged from six weeks to six years. The native coronary circulation remained unchanged in six, had developed additional proximal (left main) obstruction in four, and had advanced stenosis at the site of former anastomosis in three. Repeat revascularization consisted of new vein graft construction in eight and vein and internal mammary artery graft in four, with an average of 1.9 grafts per patient. There were no deaths. Seven of 12 patients (60%) are now asymptomatic and three of 12 (25%) are significantly improved. Patency of new grafts studied by elective repeat coronary angiography in six patients showed patency of all grafts to the left anterior descending artery and four of six grafts to other vessels. Analysis of the initial graft closures, method for selecting patients to undergo a second procedure, and operative technics believed important in safety of reoperation and avoidance of repeat early graft occlusion are presented.