ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background—The aim of this study was to use serial volumetric intravascular ultrasound (IVUS) to evaluate the effect of a paclitaxel coating on in-stent intimal hyperplasia (IH).Methods and Results—Patients were randomized to placebo (bare metal stents) or 1 of 2 doses of paclitaxel (low dose: 1.28 &mgr;g/mm2; high dose: 3.10 &mgr;g/mm2). Complete post-stent implantation and follow-up IVUS were available in 81 patients, including 25 control patients and in 28 receiving a low-dose and 28 receiving a high dose. Volumetric analysis of the stented segment and of both reference segments was performed. Baseline stent measurements and both reference measurements were similar among the groups. With increasing doses, there was a stepwise reduction in IH accumulation within the stented segment (31±22 mm3in control, 18±15 mm3in low dose, and 13±14 mm3in high dose,P<0.001). Post hoc analysis showed less IH accumulation when low- and high-dose patients were compared with control (P=0.009 andP<0.001, respectively), but not when low-dose patients were compared with high-dose patients (P=0.2). Focal late malapposition was seen in 1 high-dose patient. With increasing doses, there was no significant change in the reference segments.Conclusions—Paclitaxel-coated stents are effective in reducing in-stent neointimal tissue proliferation in humans. They are not associated with edge restenosis or significant late malapposition.

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background—A growing body of evidence from animal studies supports the hypothesis that oxidative stress-mediated mechanisms play a central role in early atherogenesis. In contrast, clinical trials with antioxidant vitamins have not produced consistent results in humans with established atherosclerosis.Methods and Results—Low-density lipoprotein receptor-deficient mice (LDLR KO) were fed a high-fat diet for 3 months to induce atheroma. At this time, 1 group of mice was euthanized for examination of atherosclerosis, and 2 other groups were randomized to receive high-fat diet either alone or supplemented with vitamin E for 3 additional months. At the end of the study, LDLR KO on a vitamin E-supplemented fat diet had decreased 8,12-iso-isoprostane (iP)F2&agr;-VI and monocyte chemoattractant protein-1 levels, but increased nitric oxide levels compared with mice on placebo. No difference in lipid levels was observed between the 2 groups. Compared with baseline, placebo group had progression of atherosclerosis. In contrast, vitamin E-treated animals showed a significant reduction in progression of atherosclerosis.Conclusions—These results demonstrate that in LDLR KO, vitamin E supplementation reduces progression of established atherosclerosis by suppressing oxidative and inflammatory reactions and increasing nitric oxide levels.

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background—In patients with acute coronary syndromes, compensatory processes are initiated, including angiogenesis and endothelial regeneration of ruptured or eroded plaques. Angiogenic growth factors like vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and basic fibroblast growth factor (bFGF) are upregulated during ischemia. However, it is unknown whether their serum levels are related to clinical outcome.Methods and Results—We measured VEGF, HGF, and bFGF levels in 1090 patients with acute coronary syndromes. Angiographic evaluation was performed at baseline as well as death, and nonfatal myocardial infarctions were recorded during 6-month follow-up. HGF and VEGF, but not bFGF, were significantly and independently associated with the patients’ outcome. Patients with elevated VEGF serum levels suffered from adverse outcome (adjusted hazard ratio, 2.50 [1.52 to 4.82];P=0.002). VEGF elevation was associated with evidence of ischemia and was a significant predictor of the effect of glycoprotein IIb/IIIa inhibition. In contrast, patients with high HGF levels had a significantly lower event rate compared with patients with low HGF levels (adjusted hazard ratio, 0.33 [0.21 to 0.51];P<0.001). HGF levels did not correlate with evidence of ischemia and did not predict the effect of abciximab. Intriguingly, however, HGF levels significantly correlated with angiographically visible collateralization of the target vessel (22.4% versus 10.5%;P<0.001).Conclusions—The angiogenic growth factors VEGF and HGF are independent predictors of the patients’ prognosis in acute coronary syndromes. Whereas VEGF elevation correlated with the evidence of myocardial ischemia and indicated an adverse outcome, HGF elevation was independent of ischemia and associated with improved collateralization as well as a favorable prognosis.

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background—Managing chest pain in the emergency department remains a challenge with current diagnostic strategies. We hypothesized that cardiac MRI could accurately identify patients with possible or probable acute coronary syndrome.Methods and Results—The diagnostic performance of MRI was evaluated in a prospective study of 161 consecutive patients. Enrollment required 30 minutes of chest pain compatible with myocardial ischemia but an ECG not diagnostic of acute myocardial infarction. MRI was performed at rest within 12 hours of presentation and included perfusion, left ventricular function, and gadolinium-enhanced myocardial infarction detection. MRI was interpreted qualitatively but also analyzed quantitatively. The sensitivity and specificity, respectively, for detecting acute coronary syndrome were 84% and 85% by MRI, 80% and 61% by an abnormal ECG, 16% and 95% for strict ECG criteria for ischemia (ST depression or T-wave inversion), 40% and 97% for peak troponin-I, and 48% and 85% for a TIMI risk score ≥3. The MRI was more sensitive than strict ECG criteria for ischemia (P<0.001), peak troponin-I (P<0.001), and the TIMI risk score (P=0.004), and MRI was more specific than an abnormal ECG (P<0.001). Multivariate logistic regression analysis showed MRI was the strongest predictor of acute coronary syndrome and added diagnostic value over clinical parameters (P<0.001).Conclusions—Resting cardiac MRI exhibited diagnostic operating characteristics suitable for triage of patients with chest pain in the emergency department. Performed urgently to evaluate chest pain, MRI accurately detected a high fraction of patients with acute coronary syndrome, including patients with enzyme-negative unstable angina.

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background—There are currently no data on the accuracy of intravenous myocardial contrast echocardiography (MCE) in detecting myocardial hibernation in man and its comparative accuracy to dobutamine echocardiography (DE) or thallium 201 (Tl201) scintigraphy.Methods and Results—Twenty patients with coronary artery disease and ventricular dysfunction underwent MCE 1 to 5 days before bypass surgery and repeat echocardiography at 3 to 4 months. Patients also underwent DE (n=18) and rest-redistribution Tl201tomography (n=16) before revascularization. MCE was performed using continuous Optison infusion (12 to 16 cc/h) with intermittent pulse inversion harmonics and incremental triggering (1:1 to 1:8). Myocardial contrast intensity (MCI) replenishment curves were constructed to derive quantitative MCE indices of blood velocity and flow. Recovery of function occurred in 38% of dysfunctional segments. MCE parameters of perfusion in hibernating myocardium were similar to segments with normal function and higher than dysfunctional myocardium without recovery of function (P<0.001). The best MCE parameter for predicting functional recovery was Peak MCI×&bgr;, an index of myocardial blood flow (area under the curve, 0.83). MCE parameters were higher in segments with contractile reserve and Tl201uptake ≥60% (P<0.05) and identified viable segments without contractile reserve by DE. The sensitivity of Peak MCI×&bgr; >1.5 dB/s for recovery of function was 90% and was similar to Tl201scintigraphy (92%) and any contractile reserve (80%); specificity was higher than for Tl201and DE (63%, 45%, and 54%, respectively;P<0.05).Conclusions—MCE with intravenous contrast identifies myocardial hibernation in humans. Prediction of viable myocardium with MCE is best using quantification of myocardial blood flow and provides improved accuracy compared with DE and Tl201scintigraphy.

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID

摘要:

Background—Balloon angioplasty guided by intravascular ultrasound (IVUS) makes it possible to choose the balloon size according to the true vessel diameter and to detect suboptimal results requiring subsequent stent implantation. The Balloon Equivalent to STent (BEST) study aimed to assess whether this strategy would give the same results as systematic stenting.Methods and Results—A total of 132 of 254 patients were randomized to IVUS-guided percutaneous transluminal coronary angioplasty (aggressive PTCA), and 122 were randomized to stenting (stent group). We hypothesized that a difference of <8% in the 6-month angiographic restenosis rate (primary end point) could be considered noninferior. The aggressive PTCA procedure was longer and had a greater use of contrast medium than stenting. In the aggressive PTCA group, crossover to stent was needed in 58 patients (44%). At 6 months, 20 of 119 patients (16.8±6.7%) in the aggressive PTCA group and 21 of 116 patients (18.1±7.0%) in the stent group had restenosis. The difference was −1.3%, with an upper limit of 95% confidence interval of 7.1% (ie, less than the noninferiority boundary). The in-stent restenosis rate was higher in the stent group (15.5% versus 5%;P=0.02). The differences in minimum lumen diameter, lumen cross-section area, and 1-year event rate were not significant.Conclusions—A strategy of IVUS-guided angioplasty with provisional stenting is feasible and safe. At the cost of a more complex procedure, it reduces the stent rate by half, with similar 6-month angiographic IVUS and clinical outcome compared with stent implantation.

ISSN:0009-7322    

出版商:OVID    

年代:2003

数据来源: OVID