Relation between coronary intimal injury and myocardial polymorphonuclear leukocyte content in the reperfused myocardium (original) (raw)
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Journal of Nuclear …, 2005
Although physical exercise is the preferred stimulus for cardiac stress testing, pharmacologic agents are useful in patients who are unable to exercise. Previous studies have demonstrated short-term repeatability of exercise and adenosine stress, but little data exist regarding dobutamine (Dob) stress or the longterm reproducibility of pharmacologic stressors in coronary artery disease (CAD) patients. PET allows accurate, noninvasive quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR). The aim of the study was to investigate the long-term reproducibility of Dob stress on MBF and CFR in CAD patients using PET. Methods: Fifteen patients with chronic stable angina and angiographically proven CAD (Ͼ70% stenosis in at least 1 major coronary artery) underwent PET with 15 O-labeled water and Dob stress at baseline (time [t] ϭ 0) and after 24 wk (t ϭ 24). MBF at rest and MBF during Dob stress were calculated for the whole left ventricle, the region subtended by the most severe coronary artery stenosis (Isc), and remote myocardium subtended by arteries with minimal or no disease (Rem). Reproducibility was assessed using the Bland-Altman (BA) repeatability coefficient and was also expressed as a percentage of the mean value of the 2 measurements (%BA). Results: Dob dose (30 Ϯ 11 vs. 031 Ϯ 11 g/kg/min; P ϭ not significant [ns]) and peak Dob rate . pressure product (20,738 Ϯ 3,947 vs. 20,047 Ϯ 3,455 mm Hg ϫ beats/min; P ϭ ns) were comparable at t ϭ 0 and t ϭ 24. There was no significant difference in resting or Dob MBF (mL/min/g) between t ϭ 0 and t ϭ 24 for the whole left ventricle (1.03 Ϯ 0.19 vs. 1.10 Ϯ 0.20 and 2.02 Ϯ 0.44 vs. 2.09 Ϯ 0.57; P ϭ ns for both), Isc (1.05 Ϯ 0.24 vs. 1.10 Ϯ 0.26 and 1.79 Ϯ 0.53 vs. 1.84 Ϯ 0.62; P ϭ ns for both), or Rem (1.03 Ϯ 0.23 vs. 1.10 Ϯ 0.26 and 2.27 Ϯ 0.63 vs. 2.26 Ϯ 0.63; P ϭ ns for both) territories. Global (1.98 Ϯ 0.40 vs. 1.90 Ϯ 0.46; P ϭ ns) and regional CFR (Isc: 1.65 Ϯ 0.40 vs. 1.67 Ϯ 0.47, and Rem: 2.25 Ϯ 0.57 vs. 2.06 Ϯ 0.51; P ϭ ns) were reproducible. The BA repeatability coefficients (and %BA) for MBF in ischemic and remote territories were 0.3 (28%) and 0.26 (24%) at rest and 0.49 (27%) and 0.58 (26%) during Dob stress. Conclusion:
Echocardiography, 2007
Background: Patients with left ventricular (LV) systolic dysfunction due to coronary artery disease (CAD) may develop stress-induced wall motion abnormalities (SWMA) with low-dose (10 µg/kg/min) dobutamine infusion. The clinical significance of low-dose SWMA is unknown. Objective: We investigated the clinical, hemodynamic and angiographic correlates of low-dose SWMA in patients with chronic ischemic LV systolic dysfunction. Methods: Seventy patients with chronic ischemic LV systolic dysfunction who had dobutamine stress echocardiography were studied. Clinical, hemodynamic, and angiographic parameters at rest and low-dose were compared between 38 patients (mean ejection fraction (EF) of 30 ± 8%) with low-dose SWMA and 32 patients (EF 30 ± 11%) without low-dose SWMA. Results: Multivariate analysis showed that the number of coronary territories with severe disease (stenosis ≥70%)(P = 0.001, RR = 6.3) was an independent predictor of low-dose SWMA. An increasing number of collateral vessels protected patients from low-dose SWMA (P = 0.011, RR = 0.25). A higher resting heart rate was a negative predictor of low-dose SWMA (P = 0.015, RR = 0.92) but no other hemodynamic variables were predictors. In the patients with low-dose SMA, regions with low-dose SWMA were more likely to be supplied by vessels with severe disease than regions without low-dose SWMA (92% vs 58%, P < 0.001). Conclusion: In patients with ischemic LV systolic dysfunction, the extent of severe disease and a lower numbers of collaterals predict the occurrence of low-dose SWMA. Low-dose SWMA is a highly specific marker for severe disease.
European Journal of Nuclear Medicine and Molecular Imaging, 1999
Electrocardiography gated single-photon emission tomography (gated SPET) allows the assessment of regional perfusion and function simultaneously and in full spatial congruency. In this study changes in global and regional left ventricular function in response to dobutamine infusion were assessed in ten healthy volunteers using sequential gated SPET myocardial perfusion acquisitions. Four consecutive gated SPET images were recorded 60 min after injection of 925 MBq technetium-99m tetrofosmin on a three-head camera equipped with focussing collimators. Two acquisitions were made at rest (baseline 1 and 2), and the third and fourth acquisitions were started 5 min after the beginning of the infusion of 5 and 10 µg kg–1 min–1 dobutamine, respectively. Systolic wall thickening (WT) was quantified using a method based on circumferential profile analysis. Left ventricular ejection fraction (LVEF) and volumes were calculated automatically using the Cedars-Sinai program. Nine of the ten subjects presented a definite increase in WT during dobutamine infusion. WT increased on average from 46%±14% at baseline to 71%±23% (range: 37%–106%; P–1 min–1 dobutamine infusion and to 85%±25% (range: 62%–123%; P–1 min–1) during 10 µg kg–1 min–1 dobutamine infusion. Apical segments showed the largest WT at baseline. The average WT response to dobutamine was similar for all parts of the myocardium. It is concluded that changes in WT induced by infusion of low-dose dobutamine can be assessed by sequential gated SPET myocardial perfusion studies. The ”stress gated SPET” protocol proposed in this study might be helpful to distinguish viable from scar tissue in patients with coronary artery disease, by demonstrating a preserved inotropic response in hypoperfused myocardium.
Journal of the American Society of Echocardiography, 2000
The goals of this study were to examine peak systolic strain as an index of regional function in an animal model of inotropic stress and ischemia, and to compare these results with peak systolic myocardial tissue Doppler velocity (MDV). Background: Myocardial tissue Doppler velocity is an objective measure of regional left ventricular responses to inotropic stimulation and ischemia, but it is affected by tethering from adjacent segments and translational movement. Myocardial Doppler strain (ε, relative change in length) is a more local measure of contractility, which can now be derived noninvasively from MDV. Methods: Eight dogs underwent graded dobutamine infusion followed by coronary occlusion. Epicardial 2-dimensional echocardiography and color MDV of the left ventricle were obtained and digitized from the short-axis view at baseline and with dobutamine doses of 2, 4, and 8 µg/kg per minute. These were repeated 0, 10, 20, 45, and 90 seconds after occlusion of the left anterior descending artery (LAD) (n = 3) or circumflex coronary artery (n = 5). Dobutamine was continued at 8 µg/kg per minute during coronary occlusion. The peak systolic radial MDV (cm/s) and systolic strain (ε s , percent thickening) in the anterior and posterior walls were measured off-line at each stage. Results: Dobutamine caused an increase in MDV (P = .0001) and ε s (P = .09) above baseline values. Coronary occlusion caused a reduction in wall motion; after 45 seconds, all nonperfused segments were hypokinetic. There was a corresponding decrease in MDV and ε s , but this occurred earlier for ε s , and the difference between ischemic and nonischemic segments was greater for ε s than for MDV (P < .03). Nonischemic regions trended to an increase in ε s (compensatory hyperkinesis), whereas MDV trended downward, probably reflecting the global decrease in left ventricular function. Conclusion: Both MDV and ε s increase with dobutamine and decrease during ischemia. ε s appears to respond to local ischemia earlier than MDV, perhaps because it is a more local measure. Thus ε s may prove to be an accurate parameter for the clinical recognition of regional ischemia. (J Am Soc Echocardiogr 2000;13:731-7.)
Hemodynamics of volume loading compared with dobutamine in severe right ventricular infarction
The American Journal of Cardiology, 1994
To compare the hemodynamic effect of volume loading with that of dobutamine infusion in severe ischemic rigm ventricular (RV) dysfuno tion, 11 patients with inferior and RV infarction complicated by low cardiac output syndrome and important hemodynamic derangement (systolic blood pressure 400 mm Hg, cardiac index <2.0 liters/min/m*, rim atrial pressure >lO mm Hg) were prospe&ively studied within 46 hours of symptom onset. After right heart catheterization, volume loading (mean 400 ml saline solution) and dobutamine infusion (5 and 10 ug/kg/min over 10 minutes) were performed according to a randomized, crossover design. Volume loading resulted in increased rim atrial (from 15 f 2 to 19 f 3 mm Hg, p eO.05) and pulmonary capillary (from 15 + 2 to 19 f 3 mm Hg, p ~0.05) pressures, without increasing cardiac index, heart rate, aortic pressure, or m and left ventricular stroke work imlex. Dobutamine (5 pg/kg/min) increased cardiac index (Born 1.5 + 0.3 to 1.9 f 0.5 liters/min/m*, p <0.05), incrementing both heart rate (from 61 & 12 to 70 + 13 beats/min, p <0.05) and stroke volume index (from 25 f 6 to 27 + 5 ml/beat/m*, p <0.05), as well as right (from 1.4 + 1.6 to 2.3 + 2.2 g . m/m*, p ~0.05) and left (from 21 + 7 to 27 + 10 g . m/m*, p eO.05) stroke work indexes; right and left ventricular filling pressures did not decrease. Dobutamine (10 pg/kg/min) si@dficantly improved myocardial performance. These data document that, in patients with low cardiac output syndrome and elevated right atrial pressure due to severe ischemic RV dysfunction, dobutamine may improve hemodynamics more than volume loading.