摘要:

Key Wordsmanaged care, emergency cardiac care, Medicare.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Key WordsEditorials, coronary disease, exercise, electrocardiography, ischemia.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Key WordsEditorials, hemoglobin, endothelium-derived factors, thrombosis.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundChronic heart failure is associated with endothelial dysfunction including impaired endothelium-mediated, flow-dependent dilation (FDD). Since endothelial function is thought to play an important role in coordinating tissue perfusion and modulating arterial compliance, interventions to improve endothelial dysfunction are imperative.Methods and ResultsTo assess the potential of physical training to restore FDD, 12 patients with chronic heart failure were studied and compared with FDD of 7 age-matched normal subjects. With a recently developed high-resolution ultrasound system, diameters of radial artery were measured at rest, during reactive hyperemia (with increased flow causing endothelium-mediated dilation), and during sodium nitroprusside, causing endothelium-independent dilation. Determination of FDD was repeated after intra-arterial infusion of NG-monomethyl-L-arginine (L-NMMA, 7 micro mol/min) to inhibit endothelial synthesis and release of nitric oxide. The protocol was performed at baseline, after 4 weeks of daily handgrip training, and 6 weeks after cessation of the training program. FDD was impaired in heart failure patients compared with normal subjects. L-NMMA attenuated FDD, indicating that the endothelial release of nitric oxide is involved in FDD. Physical training restored FDD in patients with heart failure. In particular, the portion of FDD inhibited by L-NMMA (representing FDD mediated by nitric oxide) was significantly higher after physical training (8-minute occlusion: 8.0 plus/minus 1% versus 5.4 plus/minus 0.9%; P < .05; normal subjects: 9.2 plus/minus 1%).ConclusionsThese results indicate that physical training restores FDD in patients with chronic heart failure, possibly by enhanced endothelial release of nitric oxide. (Circulation. 1996;93:210-214.)Key Wordsheart failure, endothelium, exercise, endothelium-derived factor.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundPrevious studies have shown that it is feasible to withhold anticoagulation after a successful intracoronary stent procedure with a low incidence of stent thrombosis. The importance of specific antiplatelet agents when stenting is performed without anticoagulation is unknown.Methods and ResultsAfter successful intravascular ultrasound-guided stenting, 226 patients were randomly assigned to receive either aspirin therapy alone (n = 103) or a combination of ticlopidine and short-term aspirin therapy (n = 123). Primary angiographic and clinical end points were stent thrombosis, death, myocardial infarction, the need for postprocedure coronary artery bypass surgery or repeated angioplasty, and significant medication side effects requiring termination of the medication within the first month of a successful procedure. At 1 month, the rate of stent thrombosis was 2.9% in the aspirin only group and 0.8% in the ticlopidine-aspirin group (P = .2). Cumulative major clinical events after successful stenting occurred in 3.9% of the patients in the aspirin group and in 0.8% in the ticlopidine-aspirin group (P = .1). There were no medication side effects in the aspirin group; in the combined ticlopidine-aspirin group, medication side effects occurred in 3 patients (P = .2).ConclusionsAt 1 month, there was no difference in the incidence of stent thrombosis or other clinical end points between the two poststent antiplatelet regimens. However, the relatively small size of the study and the low incidence of thrombosis events may have contributed to the failure to detect differences in angiographic and clinical end points between the two groups. (Circulation. 1996;93:215-222.)Key Wordsstents, ultrasonics.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundRecent studies demonstrated that the "no reflow" phenomenon after coronary reflow implies the presence of advanced myocardial damage. In this study, we verified the prognostic value of the detection of this phenomenon by studying complications, left ventricular morphology, and in-hospital survival after acute myocardial infarction (AMI).Methods and ResultsThe study population consisted of 126 patients with a first anterior AMI. All patients received coronary reflow within 24 hours of onset of symptoms and underwent myocardial contrast echocardiography (MCE) before and shortly after coronary reflow with an intracoronary injection of sonicated microbubbles. From contrast reperfusion patterns, patients were divided into two subsets: those with MCE no reflow (47 patients, 37%) and those with MCE reflow (79 patients). There was no difference in the frequency of arrhythmia or coronary events between the two subsets. Pericardial effusion and early congestive heart failure were observed more frequently in patients with MCE no reflow than in those with MCE reflow (26% versus 4%, P < .05; 45% versus 15%, P < .05, respectively). Congestive heart failure tended to be prolonged in those with MCE no reflow, and 3 patients (7%) of this subset died of pump failure. Left ventricular end-diastolic volume progressively increased in the convalescent stage in patients with MCE no reflow (early versus late, 145 plus/minus 43 versus 169 plus/minus 60 mL, P < .001), whereas it decreased in those with MCE reflow (154 plus/minus 42 versus 144 plus/minus 44 mL, P < .01).ConclusionsThe substantial size of the MCE no reflow phenomenon at coronary reflow conveys useful information about an outcome of coronary intervention and left ventricular remodeling in individual patients with anterior wall AMI, although these are suggestive results in a limited number of patients. (Circulation. 1996;93:223-228.)Key Wordsechocardiography, contrast media, myocardial infarction, reperfusion, microcirculation, prognosis, remodeling.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundIn acute myocardial infarction (AMI), platelets play a key role in thrombotic processes that limit the patency of the recanalized, infarct-related coronary artery and contribute to reperfusion injury. Platelet function in the course of AMI treated by direct percutaneous transluminal coronary angioplasty (PTCA) has not been evaluated.Methods and ResultsIn 15 patients with anterior AMI, peripheral venous blood samples were obtained before and 4, 8, 24, and 48 hours after recanalization of the occluded artery by PTCA. Fifteen patients who had stable coronary heart disease and were undergoing elective balloon angioplasty served as control subjects. Fibrinogen receptor function and surface expression of P-selectin on platelets were determined by flow cytometry. In addition, we evaluated generation of platelet-derived microparticles and the effect of systemic plasma from patients with AMI on normal platelet function and on platelet adhesion to human endothelial cells in culture. We found fibrinogen receptor activity and P-selectin expression on circulating platelets 8 hours after direct PTCA are decreased (P < .01). This coincided with a decrease in peripheral platelet count (P < .05) and an increase in generation of microparticles (P < .002). Twenty-four to 48 hours after PTCA, fibrinogen receptor activity and P-selectin expression increased again. Systemic plasma obtained before and after direct PTCA sensitized normal platelets to hyperaggregate in vitro (P < .001) and stimulated platelet adhesion to endothelial cells in culture (P < .01). None of the changes found in AMI were detectable in the control group.ConclusionsAfter transient apparent deactivation of circulating platelets, probably caused by sequestration of hyperactive platelets, the level of platelet activation increases in patients with AMI treated by direct PTCA. These findings underscore the need for novel antiplatelet strategies in AMI. (Circulation. 1996;93:229-237.)Key Wordsplatelets, revascularization, myocardial infarction, thrombosis, angioplasty.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundRecent reports have demonstrated the clinical use of rubidium-82 chloride (Rb-82) in combination with positron emission tomography (PET) not only as a tracer of myocardial blood flow but also as a marker of cell membrane integrity using static imaging early and late after tracer injection. The purpose of this study was to compare myocardial Rubidium-82 kinetics assessed by dynamic PET imaging as a marker for tissue viability with regional fluorine-18 fluorodeoxyglucose (FDG) uptake in patients with coronary artery disease.Methods and ResultsTwenty-seven patients with angiographically proven coronary artery disease and 5 subjects with a low likelihood for coronary artery disease underwent dynamic PET imaging under resting conditions using Rubidium-82 and FDG. Both image sequences served as input data for a semiautomated regional analysis program. This program generated polar maps representing Rubidium-82 tissue half-life and FDG utilization assessed by Patlak's approach. Myocardial tissue viability was visually determined from static Rubidium-82 and FDG images. Regions were categorized as normal, ischemically compromised, and scar tissue. Their coordinates were subsequently copied to the functional polar maps for further analyses. In normal subjects, Rubidium-82 tissue half-life was homogeneous throughout the left ventricle (90 plus/minus 11 seconds). In coronary patients, differences between Rubidium-82 tissue half-lives in normal and scar tissue were highly significant (95 plus/minus 10 and 57 plus/minus 15 seconds, respectively; P < .0001). FDG uptake in these two tissue groups was 78 plus/minus 12% and 40 plus/minus 13%, respectively (P < .0001). Ischemically compromised tissue with reduced perfusion but maintained FDG uptake displayed an Rubidium-82 half-life of 75 plus/minus 9 seconds, indicating active cellular tracer retention, which was significantly different from scar tissue. Overall agreement of tissue categorization as either viable or scar was 86% between Rubidium-82 kinetics and FDG utilization. In a subgroup of 11 patients with all three tissue types within one image set, Rubidium-82 tissue half-life discriminated between normal, ischemic, and scar tissue (97 plus/minus 9, 75 plus/minus 9, and 60 plus/minus 15 seconds, respectively; P < .01).ConclusionsThis study demonstrated a significant relationship between cell membrane integrity as assessed by dynamic Rubidium-82 PET imaging and myocardial glucose utilization as a marker for tissue viability. In regions with reduced perfusion, Rubidium-82 kinetics was different in compromised but metabolically active and irreversibly injured myocardium. The predictive value of this approach must be evaluated in follow-up studies. (Circulation. 1996;93:238-245.)Key Wordstomography, potassium, perfusion, myocardium.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundThe interpretation of exercise stress testing for coronary artery disease detection is affected by the many differences in chosen variables and mathematical methods. We conducted a prospective trial to evaluate a global muscle fatigue parameter--the blood lactate level achieved at maximal exercise--as a method of distinguishing between diseased and nondiseased coronary status.Methods and ResultsWe evaluated 236 consecutive male patients without previous myocardial infarction who had been referred for the diagnosis of coronary artery disease. None of the patients had cardiomyopathy, severe cardiac heart failure, or valvular heart disease. Blood lactate concentration at maximal exercise was measured as well as other classic variables. Correlations between variables and coronary status as assessed by coronary arteriography were described using receiver operating characteristic (ROC) curves and logistic regression analysis. The first four most powerful variables (lactate level, maximal power output, exercise duration, and percentage of maximal predicted heart rate), which are directly representative of the global functional capacity, showed values of 0.777, 0.775, 0.760, and 0.740, respectively, by ROC curve analysis. Mean plus/minus SD blood lactate level at peak exercise reached 7.68 plus/minus 2.70 mmol/L in the 153 diseased and 10.56 plus/minus 2.75 mmol/L in the 83 nondiseased patients (P < .0001). After adjustment for other variables, blood lactate level remained a significant predictor of coronary artery disease by logistic regression analysis (adjusted odds ratio, 1.2; confidence interval, 1.04 to 1.4).ConclusionsGlobal muscle fatigue as assessed by lactate levels in the blood at maximal exercise appears to be a powerful distinguisher of diseased and nondiseased coronary status. (Circulation. 1996;93:246-252.)Key Wordscoronary disease, ischemia, diagnosis, tests, exercise.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundThe presence of angiographically identified intracoronary thrombus has been variably associated with complications after coronary angioplasty. Angiography has been shown to be less sensitive than angioscopy for detecting subtle details of intracoronary morphology, such as intracoronary thrombi. The clinical importance of thrombi detectable by angioscopy but not by angiography is not known.Methods and ResultsPercutaneous coronary angioscopy was performed in 122 patients undergoing conventional coronary balloon angioplasty (PTCA) at six medical centers. Unstable angina was present in 95 patients (78%) and stable angina in 27 (22%). Therapy was not guided by angioscopic findings, and no patient received thrombolytic therapy as an adjunct to angioplasty. Coronary thrombi were identified in 74 target lesions (61%) by angioscopy versus only 24 (20%) by angiography. A major in-hospital complication (death, myocardial infarction, or emergency bypass surgery) occurred in 10 of 74 patients (14%) with angioscopic intracoronary thrombus, compared with only 1 of 48 patients (2%) without thrombi (P = .03). In-hospital recurrent ischemia (recurrent angina, repeat PTCA, or abrupt occlusion) occurred in 19 of 74 patients (26%) with angioscopic intracoronary thrombi versus only 5 of 48 (10%) without thrombi (P = .03). Relative risk analysis demonstrated that angioscopic thrombus was strongly associated with adverse outcomes (either a major complication or a recurrent ischemic event) after PTCA (relative risk, 3.11; 95% CI, 1.28 to 7.60; P = .01) and that angiographic thrombi were not associated with these complications (relative risk, 0.85; 95% CI, 0.36 to 2.00; P = .91).ConclusionsThe presence of intracoronary thrombus associated with coronary stenoses is significantly underestimated by angiography. Angioscopic intracoronary thrombi, the majority of which were not detected by angiography, are associated with an increased incidence of adverse outcomes after coronary angioplasty. (Circulation. 1996;93:253-258.)Key Wordsangioplasty, occlusion, thrombus, angioscopy.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID