Acute coronary syndromes are associated with a reduction of VLA-1+ peripheral blood T cells and their enrichment in coronary artery plaque aspirates.

Memory T cells producing interferon (IFN)γ and expressing very late antigen-1 (VLA-1) integrin collagen receptors are found in carotid atherosclerotic plaques, suggesting their involvement in coronary artery disease (CAD) as well. To determine the role of VLA-1+ T cells in CAD percent of CD3+ T cells binding monoclonal antibodies (mAb) to VLA-1 in peripheral blood (PB), and in coronary plaque material aspirated during coronary arterography and arterial blood, were analyzed in a cohort of 117 patients with CAD and 34 controls without CAD. % VLA-1+ T cells in PB was 0.63 ± 0.09% in controls compared to 0.96 ± 0.95% in patients with CAD (p<0.009). The increase was due to a marked elevation of % VLA-1+ T cells in stable CAD (1.6 ± 0.27%) whereas % VLA-1+ T cells during acute coronary syndromes (ACS) and in patients with ischemia by thalium SPECT scan had significantly lower levels. % VLA-1+ T cells in coronary artery plaque material aspirated during therapeutic angiography in patients with ACS was significantly higher than in arterial blood (1.39 ± 0.96% vs 0.75 ± 0.84%, p<0.035, n=3). Thus, % VLA-1+ T cells increases in the PB during stable CAD but decreases in ACS. The finding of their enrichment in coronary blood containing atherosclerotic plaque aspirates suggests that a shift of VLA-1+ T cells from blood to atherosclerotic plaques may play a role in plaque instability in patients with ACS.

Use of electrocardiographic depolarization abnormalities for detection of stress-induced ischemia as defined by myocardial perfusion imaging.

High-frequency mid-QRS (HFQRS) analysis was recently introduced as a tool for identification of stress-induced ischemia. The diagnostic performance of this electrocardiographic technique has not been determined in a large cohort of patients. This study compared the diagnostic performance of HFQRS analysis to conventional ST-segment analysis in detecting exercise-induced ischemia. The study included 996 patients (56 ± 10 years of age, 670 men) referred for exercise myocardial perfusion imaging (MPI), which served as the gold standard of ischemia. High-resolution electrocardiogram was used for computer analysis of HFQRS signals. Number of electrocardiographic leads with ≥50% decrease of HFQRS intensity (L(50%)) was used as an index of ischemia. Perfusion images were evaluated semiquantitatively. Receiver operating characteristic analysis demonstrated an L(50%) ≥3 as the criterion that yielded optimal sensitivity and specificity for diagnosing moderate/severe ischemia. Compared to ST-segment analysis HFQRS analysis was more sensitive (69% vs 39%, p <0.005) and more specific (86% vs 82%, p <0.05). L(50%) correlated with amount of MPI ischemia (R(2) = 0.75, p <0.0001). Multivariate logistic regression analysis demonstrated a significant incremental diagnostic value for the addition of HFQRS data to a model containing pretest and conventional exercise parameters. L(50%) was the best predictor of mild or moderate/severe MPI ischemia. In conclusion, computerized HFQRS analysis improved the diagnostic performance of conventional stress electrocardiogram in detecting exercise-induced ischemia. Thus, this technique might aid in the noninvasive evaluation of coronary artery disease.

Left ventricular ejection fraction assessment by Tl-201 gated SPECT: a comparison with echocardiography.

BACKGROUND: Few studies including only a limited number of patients have compared left ventricular ejection fraction (LVEF) assessed by 2-dimensional echocardiography (2-DE) and electrocardiography-gated Tl-201 single-photon emission computed tomography (SPECT). HYPOTHESIS: LVEF assessment by Tl-201 gated spect is comparable with LVEF assessed by 2-DE in two different echocardiographic laboratories. MATERIAL AND METHODS: Patients (n = 402) underwent Tl-201 gated SPECT in the same laboratory and 2-DE in 2 different laboratories. Patients were divided into 2 groups according to the study laboratory: group 1, at the tertiary hospital and group 2, at a community laboratory. RESULTS: LVEF evaluations were similar (mean LVEF: 50.73% +/- 11.67% by 2-DE vs 50.11% +/- 11.41% by SPECT in group 1 and 57.27% +/- 7.44% by 2-DE vs 57.41% +/- 8.37% by SPECT in group 2). All LVEF measurements were highly correlated (r = 0.7, P<.001). Baseline characteristics differed between the groups, with a higher prevalence of past myocardial infarction in the in-hospital vs the community echo group (46.7% vs 22.2%, P<.01), resulting in a higher LVEF in the latter, both by 2-DE (mean 50.7% +/- 11.7% vs 57.3% +/- 7.4%, P<.01) and SPECT (50.1% +/- 11.4% vs 57.4% +/- 8.4%, P<.01). CONCLUSIONS: The Tl-201 gated SPECT is a reliable clinical tool for LVEF assessment, with good correlation when compared to 2-DE. It may be routinely used as an alternative for patients with poor acoustic visualization and should be performed systematically in patients undergoing myocardial perfusion imaging with Tl-201.

Noninvasive detection of collateral flow to the infarct-related coronary artery in patients after myocardial infarction by Tl-201 tomographic imaging.

BACKGROUND: The determination of viability and perfusion within the infarct zone in post-myocardial infarction patients has both therapeutic and prognostic significance. Reversibility of thallium 201 uptake within the territory of the infarct-related coronary artery (IRA) as shown by single photon emission computed tomography (SPECT) is associated with a jeopardized but viable myocardium. We aimed to test the hypothesis that for post-myocardial infarction patients undergoing Tl-201 stress-redistribution SPECT, a scintigraphic pattern of distal reversibility without proximal reversibility within a defect corresponding to the IRA territory is a marker of collateral flow to the occluded culprit artery. METHODS AND RESULTS: We assessed Tl-201 SPECT imaging results of 78 patients with IRA occlusion as demonstrated by angiography 7 +/- 1 months after myocardial infarction. Angiography demonstrated the presence of collateral flow in 57 patients and its absence in 21 patients. Distal reversibility was present in 42 of the 57 patients with collateral flow (sensitivity, 74%) and was absent in 16 of the 21 patients without collateral flow (specificity, 76%). Collateral flow to the IRA was demonstrated in 42 of 47 patients with distal reversibility (group A) (positive predictive value, 89%) and absent in 16 of 31 patients with a fixed defect without reversibility (group B) (P <.001) (negative predictive value, 52%). CONCLUSIONS: In patients after myocardial infarction, a Tl-201 SPECT redistribution pattern of distal reversibility without proximal reversibility within a defect in the IRA territory is a noninvasive marker of collateral flow to the culprit artery with a high positive predictive value that may provide valuable information on patient management. A larger prospective study in an unselected patient population is needed to further evaluate the clinical value of this marker.