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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proper understanding of the pathologic process of a ruptured plaque followed by thrombus formation, with acute assessment of the deranged pathophysiology of the coronary circulation as a sequel, remains the basis for rational therapy of cardiac ischemia. With the advent of better thrombolytic regimens, improved direct reperfusion via angioplasty, and streamlined recognition/admission procedures, therapeutic strategies for dealing with acute myocardial infarction have once more turned to the options for early therapy. From recent studies of out-of-hospital thrombolysis or immediate percutaneous transluminal coronary angioplasty, the position is reinforced that "early" means the first 100 minutes. It is hoped that the large Global Utilization of Streptokinase and t-PA for Occluded Arteries (GUSTO) study, which specifically analyses the effect of early reperfusion by optimal alteplase and actilyse (recombinant tissue-type plasminogen activator [rt-PA]) versus streptokinase regimens will confirm this essential concept once and for all. Thus, when appropriate therapy--depending in the local availability of facilities--is promptly given, further reductions in myocardial infarction size and ventricular dysfunction can be achieved, resulting in mortality rates < 5%, at substantial savings in ever more expensive healthcare resources. "Early is < 100 minutes; later may be too late or too costly."
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PMID:Expanding indications for thrombolytic therapy in acute myocardial infarction. How late is too late, and how early is early: the clinician's view of the first 100 minutes. 827 56

The focus of new research efforts to improve the morbidity and mortality associated with acute myocardial infarction (AMI) has turned to adjuvant agents that show promise of improving outcomes following coronary thrombolysis. We enrolled 162 patients with AMI in a randomized trial comparing front-loaded tissue-plasminogen activator (t-PA) plus weight-adjusted heparin with anisoylated plasminogen streptokinase activator complex (APSAC) without heparin as well as standard-dose (325 mg) and low-dose (81 mg) aspirin. The primary end point was an in-hospital morbidity profile; secondary end points were clinical and angiographic potency and hemorrhagic events. Selected sites performed an electrocardiographic substudy to determine the time to 50% ST-segment recovery and the time to steady state. Although the trial was terminated when the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries-I trial showed that t-PA had a significant mortality advantage over streptokinase, important trends were evident. Patients given t-PA and heparin were better anticoagulated (p = 0.001), yet AP-SAC-treated patients had more bleeding complications. The primary end point favored t-PA (25.4% vs 31.3%), and the secondary end points were similar in both groups. In the electrocardiographic substudy, the t-PA group achieved both 50% ST-segment recovery and steady-state recovery sooner than the APSAC group. Patients taking low-dose aspirin had lower in-hospital mortality and less recurrent ischemia but more strokes than the standard-dose aspirin group. Thus, this trial demonstrated trends favoring front-loaded t-PA with weight-adjusted heparin over APSAC without heparin in the treatment of AMI. The use of low-dose aspirin did not appear to impose a loss of protection from adverse events, nor did standard-dose aspirin increase serious bleeding.
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PMID:A randomized factorial trial of reperfusion strategies and aspirin dosing in acute myocardial infarction. The DUCCS-II Investigators. 862 29

Intraarterial thrombolysis is used increasingly for management of arterial and bypass graft occlusions. Current research has been directed at the indications for and methods of catheter-directed thrombolysis. Streptokinase, urokinase, and tissue plasminogen activator (t-PA) are the most commonly used agents. They are administered by a variety of techniques and in various doses involving intrathrombic infusions, thrombus lacing, high-dose bolus therapy, and pulse-spray lysis. The latter methods appear to produce thrombolysis within a few hours, so this chemical therapy has the potential to become the first-line management for all episodes of acute limb ischemia. The role of thrombolysis is to return patients to their prethrombotic or preembolic state, so the underlying condition can be treated by radiologic intervention, surgery, or anticoagulation. Intraarterial thrombolysis is indicated for occlusions of less than 2 weeks' duration where the limb is able to withstand a period of further ischemia. Older occlusions should be treated by surgery, reserving intraoperative lysis for specific situations.
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PMID:Lower limb intraarterial thrombolysis as an adjunct to the management of arterial and graft occlusions. 866 48

Primary percutaneous transluminal coronary angioplasty (PTCA) is not used in all hospitals capable of performing it because the data regarding results are either not known or not easily interpreted. Unlike pharmaceutical trials, which receive $30-50 million in research funds, virtually all trials of PTCA have been unfunded. Nevertheless, several groups have conclusively proved the benefit of primary PTCA over thrombolysis. In a 1995 meta-analysis, PTCA proved superior to thrombolytic therapy in reducing death and reinfarction. The Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-IIB) substudy confirmed this fact with 94% certainly. Other studies were designed to refine the angioplasty technique. In the Primary Angioplasty in Myocardial Infarction (PAMI-I) study, acute catheterization was used to stratify patients and identified a low-risk population whose mortality equaled that of patients treated electively. Compared with clinical risk factors, angiographic findings enhanced the power to predict mortality three-fold. The high-risk subset with acute myocardial infarction (MI) was also randomized to treatment with or without prophylactic intra-aortic balloon pumping (IABP). Although IABP caused no complications, it had no positive effect on primary endpoints (death, recurrent MI, and reocclusion) and did not improve left ventricular function at 6 months. One limitation of primary PTCA is a high rate of late restenosis (30-50% at 6 months). In a pilot study we are examining the role of stents in conjunction with primary PTCA. Early results indicate that in the 69% of patients eligible for stent placement, in-hospital events were uncommon (no deaths, no reinfarctions, low rate of recurrent ischemia) and the need for repeat revascularization was infrequent.
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PMID:Aggressive intervention for myocardial infarction: angioplasty, stents, and intra-aortic balloon pumping. 875 44

Our purpose was to evaluate the outcomes of patients with prior coronary angioplasty who underwent thrombolysis for new acute myocardial infarction (AMI) in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries-I trial. Baseline characteristics and clinical outcomes were compared between patients with (n = 1,647) and without (n = 39,150) previous angioplasty. The relations among prior angioplasty, clinical outcomes, and treatment effects were examined with logistic regression modeling. Patients with previous angioplasty tended to be younger and presented sooner after symptom onset, but had more multivessel disease and lower ejection fractions. Unadjusted mortality was significantly lower in the prior-angioplasty group at 24 hours (1.8% vs 2.7%, p = 0.03) and 30 days (5.6% vs 7.0%, p = 0.036). Although most of the survival advantage was due to low-risk characteristics in this group (lower age and heart rate and fewer anterior wall AMIs), prior angioplasty remained a weak but independent predictor of survival. Recurrent ischemia and reinfarction occurred more often in the prior-angioplasty group, as did bypass surgery (12.2% vs 8.5%) and repeat angioplasty (34.5% vs 21.4%). Patients with prior angioplasty and prior AMI had lower 30-day mortality than those with prior infarction alone (6.3% vs 12.6%, p < 0.01). Treatment effects on 30-day mortality were similar among patients with prior angioplasty (odds ratio 1.2 for accelerated tissue-plasminogen activator v. combined streptokinase arms, 95% confidence interval 0.73 to 1.9). Patients with prior angioplasty who present with AMI have fewer in-hospital adverse events and lower 30-day mortality than those without such a history.
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PMID:Thrombolytic therapy for patients with prior percutaneous transluminal coronary angioplasty and subsequent acute myocardial infarction. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries. 897 Apr 3

ST-segment elevation acute myocardial infarction (AMI) in patients who have undergone previous coronary artery bypass grafting (CABG) is associated with low reperfusion rates and poor outcome after fibrinolytic therapy. The efficacy of a combination strategy (reduced fibrinolytic plus platelet glycoprotein IIb/IIIa agent) in this setting is unknown. In the Global Use of Streptokinase and TPA for Occluded coronary arteries V (GUSTO V) trial, 553 patients with a history of CABG were treated with standard-dose reteplase (n = 273), or half-dose reteplase and full-dose abciximab (n = 280) in the first 6 hours of evolving ST-segment elevation MI. Mortality at 30 days was significantly higher in patients who underwent prior CABG compared with patients with no prior CABG (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.21 to 2.24, p = 0.001). In patients who underwent prior CABG, mortality at 7 days was reduced 15% with combination therapy compared with reteplase alone, which was not statistically significant (OR 0.85, 95% CI 0.40 to 1.81, p = 0.66). Patients who underwent prior CABG treated with the combination therapy had fewer episodes of recurrent ischemia (OR 0.60, 95% CI 0.37 to 0.96, p = 0.02), high degree atrioventricular block (OR 0.17, 95% CI 0.02 to 0.82, p = 0.01), and ventricular tachycardia (OR 0.29, 95% CI 0.07 to 0.96, p = 0.04). There was a trend toward reduced urgent revascularization (OR 0.61, 95% CI 0.36 to 1.03, p = 0.06) but no significant difference in reinfarction (OR 0.61, 95% CI 0.31 to 1.52, p = 0.40). In the GUSTO V trial, patients who underwent prior CABG had significantly higher event rates compared with patients without CABG. As in the overall trial, combination therapy in patients who underwent prior CABG led to a consistent reduction in key secondary complications of AMI, including recurrent ischemia and a trend toward reduced urgent revascularization.
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PMID:Outcome of acute myocardial infarction in patients with prior coronary artery bypass grafting treated with combination reduced fibrinolytic therapy and abciximab. 1245 May 98


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