Coronary stenting plus platelet glycoprotein IIb/IIIa blockade compared with tissue plasminogen activator in acute myocardial infarction. Stent versus Thrombolysis for Occluded Coronary Arteries in Patients with Acute Myocardial Infarction Study Investigators

BACKGROUND

Prevention of myocardial damage is the main goal of all reperfusion therapies in patients with acute myocardial infarction. The relative efficacy of various reperfusion strategies is under intensive investigation. We assessed whether coronary stenting combined with the blockade of platelet glycoprotein IIb/IIIa receptors produces a greater degree of myocardial salvage than fibrinolysis with an accelerated infusion of alteplase, a tissue plasminogen activator, in patients with acute myocardial infarction.

METHODS

A total of 140 patients were enrolled in the randomized trial; 71 were assigned to receive a stent plus abciximab, and 69 to receive intravenous alteplase. The primary end point was the degree of myocardial salvage, determined by means of serial scintigraphic studies with technetium Tc 99m sestamibi. The secondary end point was a composite of death, reinfarction, and stroke within six months after randomization.

RESULTS

In the group that received a stent plus abciximab, the median size of the final infarct was 14.3 percent of the left ventricle (25th and 75th percentiles, 6.8 and 24.5 percent), as compared with a median of 19.4 percent (25th and 75th percentiles, 7.9 and 34.2 percent) in the alteplase group (P=0.02). This difference was due to the larger salvage index (the percentage of the left ventricle that was salvaged, divided by the percentage that was compromised by the initial perfusion defect) in the stent group: 0.57 (25th and 75th percentiles, 0.35 and 0.69), as compared with 0.26 (25th and 75th percentiles, 0.09 and 0.61; P<0.001). The cumulative incidence of death, reinfarction, or stroke at six months was lower in the stent group than in the alteplase group (8.5 vs. 23.2 percent. P=0.02; relative risk, 0.34; 95 percent confidence interval, 0.13 to 0.88).

CONCLUSIONS

In patients with acute myocardial infarction, coronary stenting plus abciximab leads to a greater degree of myocardial salvage and a better clinical outcome than does fibrinolysis with a tissue plasminogen activator.

Extent of cardiac sympathetic neuronal damage is determined by the area of ischemia in patients with acute coronary syndromes

BACKGROUND

Prior studies have demonstrated that acute ischemic injury causes sympathetic neuronal damage exceeding the area of necrosis. The aim of this study was to test the hypothesis that sympathetic neuronal damage measured by (123)I-metaiodobenzylguanidine (MIBG) imaging would be determined by the area of ischemia as reflected by area at risk in patients undergoing reperfusion therapy for acute coronary syndromes.

METHODS AND RESULTS

In 12 patients, the myocardium at risk was assessed by (99m)Tc-sestamibi SPECT before reperfusion, and infarct size was measured by follow-up (99m)Tc-sestamibi SPECT 1 week later. All patients also underwent (123)I-MIBG SPECT within a mean of 11 days after onset. The SPECT image analysis was based on a semiquantitative polar map approach. Defect size on the (123)I-MIBG or (99m)Tc-sestamibi SPECT was measured for the left ventricle (LV) with the use of a threshold of -2.5 SD from the mean value of a normal database and was expressed as %LV. The (123)I-MIBG defect size (47+/-18%LV) was larger than the infarct size (27+/-23%LV, P<0. 001) but was similar to the risk area (49+/-18%LV, P=NS). Furthermore, the (123)I-MIBG defect size was closely correlated with the risk area (r=0.905, P<0.001).

CONCLUSIONS

Sympathetic neuronal damage measured by (123)I-MIBG SPECT is larger than infarct size and is closely related to risk area, suggesting high sensitivity of neuronal structures to ischemia compared with myocardial cells.

Regional myocardial wall thickening and global ejection fraction in patients with low angiographic left ventricular ejection fraction assessed by visual and quantitative resting ECG-gated 99mTc-tetrofosmin single-photon emission tomography and magnetic resonance imaging

We investigated the use of visual and quantitative technetium 99m tetrofosmin ECG-gated single-photon emission tomography (SPET) for the assessment of regional myocardial wall thickening (WT) and left ventricular (LV) ejection fraction (EF) in comparison with gated magnetic resonance imaging (MRI) in patients with a low angiographic LVEF. Gated SPET using 99mTc-labelled flow tracers offers potential for simultaneous assessment of myocardial perfusion and LV function. Few data are available on the use of visual and quantitative gated SPET in patients with low LVEF. In this study 21 patients with low angiographic LVEF (mean 37%+/-5%) were studied. Resting gated 99mTc-tetrofosmin SPET and gated MRI were performed within 48 h. WT was assessed by visual interpretation (five point score) and quantitative analysis based on count increase. There was good agreement for EF measurements by MRI and gated SPET (mean EF: 33%+/-12% vs 35%+/-11%, r = 0.86, P<0.001). Areas under receiver operator characteristic curves (AUC) for differentiation between MRI WT score points ranged from 0.60 to 0.66 for visual SPET WT analysis, from 0.59 to 0.71 for delta count increase values and from 0.46 to 0.60 for % WT, indicating substantial overlap between WT categories. Absolute agreement for visual WT between MRI and gated SPET ranged from 25% to 57% (kappa 0.03-0.25) depending on tracer uptake, and was limited in areas with moderate to severe perfusion defects (kappa 0.03-0.13). It is concluded that gated SPET provided reliable estimates of regional WT and global function in patients with low angiographic LVEF.

Multicentre evaluation of an immunological rapid test for the detection of troponin T in whole blood samples

In a multicentre study we assessed the analytical and diagnostic performance of a rapid test (TROPT rapid test, Boehringer Mannheim; in the USA: CARDIACT) for cardiac troponin T compared to quantitative troponin T ELISA and creatine kinase-MB mass determinations. The rapid test requires 150 microliters of heparinized or EDTA whole blood; serum is not suitable. Interference testing with biotin, haemoglobin and 27 standard drugs yielded no significant influence in the physiological range. Skeletal muscle troponin T concentrations > or = 40 micrograms/l gave positive results with the rapid test. We used the rapid test for 369 samples from 203 patients with suspected acute coronary syndromes and compared the results to troponin T ELISA and creatine kinase-MB mass. 90 patients (44%) were primarily classified as having myocardial infarction by the WHO criteria. Twenty-two (20%) of the 113 non-myocardial infarction patients were unstable angina pectoris cases showing increased troponin T ELISA but not increased creatine kinase-MB mass values. Consequently, these were classified as minor myocardial damage cases. The rapid test was positive in 99% of all samples with a troponin T ELISA value > or = 0.30 micrograms/l and negative in 95 to 96% of all samples below this value. Diagnostic sensitivities for the detection of acute myocardial infarction within the first 12 hours after onset of pain were the same, 90%, for the rapid test, troponin T ELISA and creatine kinase-MB mass. After 48 hours, diagnostic sensitivity of creatine kinase-MB mass sharply decreased whereas that of the troponin T assays remained close to 100% beyond 72 hours after onset of symptoms. Diagnostic specificities for acute myocardial infarction (WHO) of all markers remained between 80 and 100% over this time. The diagnostic sensitivity of the rapid test for the detection of high risk unstable angina pectoris patients with minor myocardial damage was nearly the same as for troponin T ELISA. A major advantage of the rapid test is the ease of use and 20 minute turn around time. This facilitates the detection of increased troponin T at alternate sites.