Electrocardiographic evidence of myocardial salvage after thrombolysis in acute myocardial infarction

There is a need for a simple clinical measurement that will indicate the extent of myocardial salvage after successful thrombolysis. This study examined whether coronary artery reperfusion reduced the infarct size as assessed electrocardiographically after thrombolytic treatment. The sum of the (sigma) ST segment area in leads showing ST segment elevation in the 12 lead electrocardiogram at presentation was used as an index of potential myocardial injury (initial ischaemic index). The evolved infarct size at 48 h was assessed by a QRS scoring system. Two groups of patients, both admitted with anterior myocardial infarction within 6 h of onset, were studied. Group 1 (n = 35) received analgesia only and group 2 (n = 33) received thrombolytic treatment either by the intracoronary (streptokinase, n = 13) or intravenous route (anistreplase, n = 20). Reperfusion was assessed angiographically. The mean (SD) potential infarct size assessed by the initial ischaemic index was similar in both groups (group 1, sigma ST area = 115 (60) mm2 and group 2 = 126 (77 mm2). The QRS score representing evolved infarct size was significantly lower in the treated group (4.1 (2.5] than in group 1 (7.8 (2.6]. The 95% confidence intervals for QRS scores based on the admission sigma ST area from patients with successful reperfusion were applied to a third set of patients (n = 22) to test the ability of the admission ST area (myocardial injury) to predict the QRS score accurately. While patients with successful reperfusion had significantly lower QRS scores than those who did not (4.5 (3.1) versus 9.3 (3.4)), the wide confidence intervals caused by inter-individual variability precluded an accurate prediction of the QRS score in an individual from the sigma ST area at time of presentation. There was no difference in infarct size in patients treated early (</= 3 h) (QRS score 4.2(2.8)) or later (3-6 h) (4.1(2.1)). This study provides evidence that sequential electrocardiographic changes are reduced in patients with anterior infarction who achieve reperfusion after thrombolytic treatment and that this benefit is shown with treatment given up to six hours after infarct onset. None the less, the relation between the initial ischaemic index and the evolved QRS score has wide confidence intervals, reflecting inter-individual variability, and does not allow the prediction of a QRS score in an individual patient.

Effects of successful intravenous reperfusion therapy on regional myocardial function and geometry in humans: a tomographic assessment using two-dimensional echocardiography

This study tested the hypothesis that reperfusion therapy might provide benefit at two levels: 1) by arresting infarct migration at the endocardial level, such that partial or complete recovery of regional function occurs; and 2) if the former is not achieved, by preventing complete or near complete transmural migration and subsequent infarct expansion. To test this hypothesis, 24 patients who received intravenous streptokinase therapy within 4 h of chest pain were studied prospectively. All patients underwent two-dimensional echocardiography at the time of admission and 1, 2, 3 and 10 days later. The patients also underwent coronary angiography 2 h after completion of streptokinase therapy. Although 18 (75%) of the 24 patients had a patent infarct-related artery, only 8 (45%) of the 18 patients with this finding showed improvement in regional function. Improvement was not evident until 3 to 10 days after streptokinase therapy. In addition to the presence of an open infarct-related artery, the interval between chest pain and onset of streptokinase therapy (2.5 +/- 0.5 versus 3.2 +/- 0.7 h, p = 0.02) differed significantly between patients who did or did not show improved regional function. Of the 15 of 16 patients with no improvement in regional function, 4 showed infarct expansion, and all had a closed infarct-related artery compared with only 2 of the 11 not showing expansion (p = 0.01). In conclusion, intravenous streptokinase given within 4 h of chest pain results in improvement in regional function in about 33% of the patients, presumably by arresting the infarction within the endocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

[Successful fibrinolytic treatment in a patient with acute mitral prosthetic thrombosis]

A case is described of a 50 year-old man with an acute prosthetic dysfunction due to valve thrombosis and cardiogenic shock, on a prosthesis in the mitral position (Bjork-Shiley). The patient was promptly treated with a streptokinase in two infusions 1.5 x 10(6) UI over 180 and 90 minutes, respectively. Early clinical, fluoroscopy and echocardiography improvement was observed. The authors comment the present role of the thrombolytic therapy in front of surgery of prosthetic valve thrombosis.

Thrombosed iliac venous aneurysm: a rare cause of left lower extremity venous obstruction

A patient who had deep venous obstruction of the left lower limb was shown to have thrombosis of a venous aneurysm of the left common iliac vein that measured 8.8 cm at the largest diameter. The aneurysm was suspected on the basis of preoperative noninvasive testing. Findings at surgery suggested the left iliac vein was being compressed by the right iliac artery. The aneurysm was resected and prosthetic graft material was used to reconstruct the venous system. A 22-month follow-up is recorded. Literature pertaining to the case is discussed.

One-year prognosis of primary ventricular fibrillation complicating acute myocardial infarction. The GISSI (Gruppo Italiano per lo Studio della Streptochinasi nell'Infarto miocardico) investigators

The 1-year prognosis of 293 patients discharged alive from the hospital after acute myocardial infarction (AMI), who experienced primary ventricular fibrillation (VF) in the acute phase, was compared with that of a reference group of 6,337 patients identified from the same population included in the Gruppo Italiano per lo Studio della Streptochinasi nell'Infarto miocardico (GISSI) trial. There was no difference in the 6- and 12-month mortality between the patients with primary VF and the reference group (3.7 vs 2.7% and 4.1 vs 4.2%, respectively). Survival of the 2 groups was also similar when patients were stratified according to infarct site (anterior and posterior), and whether or not they received treatment with streptokinase during AMI. Thus, long-term mortality of patients discharged alive after AMI complicated by primary VF is low and is not influenced by previous fibrinolytic therapy or by infarct site. The excess mortality of patients with primary VF is confined to the hospital phase, after which survivors represent a low-risk subgroup.

Relation of plasma D-dimer concentrations to coronary artery reperfusion before and after thrombolytic treatment in patients with acute myocardial infarction

This study was designed to investigate the possible role of pre- and posttreatment plasma D-dimer concentration as a reflection of coronary artery thrombolysis. Blood was collected from 206 patients with angiographically documented acute coronary occlusion presenting within 6 hours of symptom onset who were enrolled in a prospective study comparing intravenous APSAC (30 U) (IV-APSAC) with intracoronary streptokinase (160,000 U) (IC-SK). D-dimer concentrations in 104 patients after IV-APSAC therapy were higher than in 90 patients after IC-SK (mean +/- standard error, 1,009 +/- 60 vs 603 +/- 45, p less than 0.001), but there was no difference in patients with and without reperfusion (1,096 +/- 88 vs 875 +/- 67, p = 0.1 for IV-APSAC, and 587 +/- 48 vs 634 +/- 95, p = 0.6 for IC-SK). The median concentrations before treatment were similar in the IV-APSAC and IC-SK groups (93 and 90 ng/ml, respectively). These were higher than the value in 25 ambulatory control subjects (72 ng/ml) but lower than in 29 post-AMI (6 to 30 hours) patients and in preoperative orthopedic patients (140 ng/ml each). There was no difference in D-dimer concentrations in patients with grade 0 or grade 1 coronary artery occlusion (median 85 vs 90 ng/ml) or in patients with or without ultimate successful reperfusion (median 85 vs 93 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

[Time peak of creatine kinase activity in various sites of myocardial infarct]

The authors studied the differences in the period of time spanning the onset of anginous pain and the peak of plasma creatine kinase activity in different areas of the left ventricle in patients with acute myocardial infarction. The patients were given either intravenous or intracoronary thrombolytic agents. The involvement of different areas of the cardiac muscle had a major effect on the lenght of time until the peak of creatine kinase activity was reached. This reduces the significance of this parameter which as so far been seen as a noninvasive indicator of the patency of the artery supplying the site of the infarction. The authors also refer to other familiar factors likely to alter the role of this parameter.

[Results and prospects of studying thrombosis formation in ischemic heart disease]

On the basis of own investigations and literary data of recent years the author discusses problems of frequency and location of thromboembolic complications in ischemic heart disease, their pathogenesis, effect on the course of acute myocardial infarction, clinico-laboratory criteria of diagnostics of the intravascular coagulation syndrome, current methods of diagnosis, treatment and prophylaxis.

Use of a proprietary database to examine lengths of hospital stay of patients who received drug therapy for acute myocardial infarction

Lengths of hospital stay of patients who received streptokinase therapy and of patients who received conventional i.v. heparin or nitroglycerin therapy for acute myocardial infarction (AMI) were determined using the International Health Services, Ltd., (IHS) database. Patients in all IHS-participating hospitals who had received streptokinase in conjunction with an AMI between October 1985 and September 1986 were identified from the database. Diagnosis-related groups (DRGs) 121 and 122 were found to contain patients who potentially could serve as the study population. Based on examination of length-of-stay data from the medical record database at the study hospital, the IHS study population was refined to include AMI patients 75 years of age or younger with stage 2 disease (intermediate severity) in DRG 121 or stage 1 disease (least severe) in DRG 122 and a length of stay of at least seven days. Patients who met those criteria and had been treated with heparin, nitroglycerin, or both served as a control group. The mean length of stay of patients treated with streptokinase (113 patients) was significantly shorter than that of patients treated with heparin (1332 patients) or nitroglycerin (752 patients). Patients treated with streptokinase had a length of stay 1.2 days shorter than patients treated with heparin and 1.3 days shorter than patients treated with nitroglycerin. The database proved to be useful for determining lengths of patient stay associated with thrombolytic and conventional medical therapy for AMI. Thrombolytic therapy may be a cost-effective treatment for AMI because length of stay may be somewhat shorter.

Comparison of tissue plasminogen activator and streptokinase in the management of acute myocardial infarction

Thrombolysis is well established as effective therapy in AMI. Two thrombolytic agents, streptokinase and tissue plasminogen activator (tPA), are now widely available for clinical use. These agents have different effects, and there has been considerable debate as to which is superior. Both are effective in preserving myocardial function and reducing mortality. However, the confidence limits of these findings overlap, and no firm conclusions can be made from comparing trials enrolling different populations with different baseline characteristics and ancillary treatments such as angioplasty. There have been few "head-to-head" comparisons. These trials show that tPA achieves better lysis rates than streptokinase, but the theoretic advantage of fibrin specificity does not result in fewer adverse effects or greater preservation of LV function. Although each drug may have specific indications, the drugs appear similar in clinical benefit, and further comparison trials are required.

A canine model of coronary artery thrombosis with superimposed high grade stenosis for the investigation of rethrombosis after thrombolysis

A canine model was developed to investigate coronary artery thrombolysis and reocclusion in the setting of endothelial cell damage and fixed stenosis, which simulate anatomic features occurring in patients with acute myocardial infarction. In open chest dogs, endothelial cell damage was produced in the left anterior descending coronary artery by external compression with blunt forceps, greater than 90% stenosis was obtained by an external constrictor and thrombosis was induced by instillation of thrombin and fresh blood in an isolated arterial segment. In the absence of stenosis, intravenous infusion of 750,000 U of streptokinase over 1 h caused reperfusion in five of six dogs in 34 +/- 25 min (mean +/- SD). Urokinase, 600,000 U intravenously over 30 min followed by 600,000 U over 30 min by the intracoronary route, induced reperfusion in three of four dogs in 65 +/- 23 min. Recombinant two chain tissue-type plasminogen activator (rt-PA) (G11021), infused intravenously at a rate of 15 micrograms/kg per min for 30 min or until reflow, induced reperfusion in all 12 dogs in 28 +/- 13 min. In the absence of coronary artery stenosis, spontaneous reocclusion did not occur within 2 h after the end of the infusion. In the presence of the coronary artery constrictor, which reduced the blood flow to 40 +/- 10% of baseline, streptokinase, urokinase and rt-PA caused coronary thrombolysis to proceed at comparable or only slightly slower rates. Cyclical reocclusion during or after the end of infusion of these thrombolytic agents, caused by platelet-rich thrombus, was almost invariably observed, generally within 30 min after the onset of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Thrombolytic therapy for acute myocardial infarction

Thrombolytic therapy in AMI restores infarct artery patency, preserves LV function, and decreases hospital mortality. Although hemorrhagic complications including stroke can occur, the incidence of stroke is not increased compared with control groups. Aspirin must be administered as soon as possible to inhibit platelet function, and an adjunctive role for early beta-blocker therapy may be important. Acute cardiac catheterization and coronary angioplasty need not be routinely performed in stable patients after tPA therapy, but should be considered in unstable patients. Two trials suggest that aggressive use of coronary angioplasty or bypass graft surgery before hospital discharge to preserve infarct artery patency and to prevent postinfarction ischemia is associated with an important improvement in long-term prognosis. Thrombolytic therapy should be considered standard care for patients whose ischemic chest pain lasts 20 min to at least 6 h in duration and who have an injury current on their ECG unless they are at increased risk for bleeding. The need for and timing of cardiac catheterization, coronary angioplasty, and surgical revascularization after AMI requires further evaluation.

Fibrinolytic profiles in local low-dose thrombolysis with streptokinase and recombinant tissue plasminogen activator

Fibrinolytic parameters have been monitored in 44 patients undergoing local low-dose intra-arterial thrombolysis for acute peripheral arterial ischaemia. Streptokinase (Sk), at a dose of 5,000 units/hr with 250 units/hr heparin, was used in 23 patients and recombinant tissue plasminogen activator (r-tPA) at a dose of 0.5 mg/hr was used in 21 patients. Successful lysis was seen in 18 (86%) patients following r-tPA and in 15 (65%) patients following streptokinase. There were 4 minor haematomas in each group usually at the catheter entry site. Both agents produced a systemic effect, which was still seen 12 hours post-infusion. However, that produced by r-tPA was delayed and significantly reduced compared to that produced by Sk. These results confirm the relative fibrin specificity of r-tPA. When used as a continuous low-dose intra-arterial infusion, r-tPA offers a significantly lower, potentially safer, systemic effect than conventional therapy with streptokinase.

Randomised double-blind trial of recombinant pro-urokinase against streptokinase in acute myocardial infarction. PRIMI Trial Study Group

In a prospective, double-blind, randomised trial, 401 patients with a first acute myocardial infarction were treated within 4 h of onset of symptoms with 80 mg recombinant pro-urokinase or single-chain urokinase plasminogen activator (rscu-PA; proposed INN saruplase) intravenously given as a 20 mg bolus followed by 60 mg infusion for 60 min (198 patients), or 1.5 million IU streptokinase infused over 60 min (203 patients). The first two angiograms were taken at 60 min and at 90 min. Angiography was repeated at 24-36 h. Patency rates at 60 min were 71.8% for rscu-PA and 48.0% for streptokinase (p less than 0.001) and at 90 min they were 71.2% and 63.9%, respectively (p = 0.15). At 24-36 h 6/121 patients treated with rscu-PA and 5/114 patients treated with streptokinase showed reocclusion of the vessel. At the end of the thrombolytic infusion (60 min) fibrinogen concentration had decreased to 0.44 (0.23-1.27) g/l (median, 1st and 3rd quartile) in patients treated with rscu-PA and to 0.17 (0.06-0.27) g/l in patients treated with streptokinase (p less than 0.001). Concentrations of fibrin(ogen) degradation products rose to 96 (24-240) mg/l after rscu-PA and to 240 (192-360) mg/l after streptokinase (p less than 0.001). Bleeding complications were less common in the rscu-PA than in the streptokinase group (p less than 0.01). Thus intravenous rscu-PA led to higher patency rate, earlier reperfusion, less disturbance of haemostasis, and fewer bleeding complications than did intravenous administration of streptokinase.

Importance of effective, early and sustained reperfusion during acute myocardial infarction

The determinants of myocardial salvage after thrombolytic therapy during acute myocardial infarction (AMI) have not been clearly defined. In 1984, a prospective randomized trial was undertaken to define the relations between delay to treatment and effectiveness of perfusion to salvage of myocardium. Patients presenting within 2 hours of symptom onset received intravenous streptokinase immediately (group 1, 20 patients) or 5 hours after symptom onset (group 2, 16 patients). Effective perfusion (less than or equal to 90% residual stenosis with rapid distal runoff) occurred in 63% of patients in both groups. Five patients, all in group 1, had recurrent AMI; 4 of the 5 had effective perfusion. There was no group difference in left ventricular ejection fraction at baseline or before discharge. However, group 1 patients with effective perfusion tended to have a greater predischarge mean ejection fraction than those in group 1 with ineffective perfusion (53 +/- 13 vs 44 +/- 16%, p less than 0.10) and had a greater mean value than those in group 2 with ineffective perfusion (53 +/- 13 vs 38 +/- 17%, p less than 0.03). The ejection fraction did not change significantly between admission and discharge in either group, but it increased significantly in group 1 patients with effective perfusion and no recurrent AMI (delta EF = +6 +/- 8%, p less than 0.04). Group 1 patients with ineffective perfusion had a significant decrease in ejection fraction (delta EF = -4 +/- 4%, p less than 0.04). In group 2 patients the ejection fraction did not change, regardless of the state of perfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

[Intravenous streptokinase in acute myocardial infarction. Reduction of early in-hospital mortality]

A randomized study of the effects of intravenous streptokinase was performed in 214 patients with an acute myocardial infarction of less than 4 hours of whom 110 were included in the therapeutic group (SK) and 104 in the control group (C). Incidence of angiographic recanalization was higher in SK group (71 vs 28%, p less than 0.001) as that of non-significant residual coronary artery stenosis (less than 70%, 16% vs 3%, p less than 0.005), particularly in young patients (less than 45 years; 42% vs 8%, p less than 0.05). However, SK group presented a higher incidence of severe residual stenosis (90-99%) (SK, 42% vs C, 22%, p less than 0.01). Ejection fraction was higher among recanalized patients in both groups. Peak CPK-MB occurred earlier in SK group (13 vs 19 hours, p less than 0.001) and also among the recanalized patients of each group (SK, 12 vs 16 hours, p less than 0.001; C, 15 vs 21 hours, 0.002). The course of ST segment was similar in the 2 groups. The occurrence of ventricular arrhythmias within the first hour was greater in SK group (40% vs 20%, p less than 0.002), whereas the incidence of pericarditis (14% vs 35%, p less than 0.001) and of early mortality (less than 5 days, 2% vs 10%, p less than 0.02) was lower in SK group. The incidence of cardiac rupture, confirmed at necropsy in each of the 5 cases studied, was also lower in SK group (1 vs 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative radionuclide assessment of regional ventricular function after thrombolytic therapy for acute myocardial infarction: results of phase I Thrombolysis in Myocardial Infarction (TIMI) trial

In Thrombolysis in Myocardial Infarction (TIMI) Phase I,290 patients with acute myocardial infarction were randomized to either intravenous recombinant tissue-type plasminogen activator (rt-PA) or intravenous streptokinase. Two hundred twenty-nine patients had radionuclide ventriculograms at discharge for assessment of global and regional left ventricular ejection fraction. Among these 229 patients 185 had totally occluded infarct-related arteries, and angiographic reperfusion of the infarct-related artery occurred in 69% of patients treated with rt-PA and 28% of patients treated with streptokinase (p less than 0.001). Mean global left ventricular ejection fraction was not different for rt-PA-treated patients compared with streptokinase-treated patients (0.46 versus 0.45). However, the average regional ejection fraction of the regions subtended by the infarct-related artery showed a trend toward better average infarct region ejection fraction in patients treated with rt-PA than in patients treated with streptokinase (0.40 versus 0.36; 0.05 less than p less than 0.06). Analysis of data according to perfusion status of the infarct-related artery showed no difference in mean global left ventricular ejection fraction between patients with sustained versus nonsustained reperfusion (0.47 versus 0.44). However, there was better average regional ejection fraction of the region subtended by the infarct-related artery in patients with sustained reperfusion (0.40 versus 0.36; p less than 0.01). Thus, quantitation of regional left ventricular function by radionuclide techniques provides a noninvasive means for evaluating the effects of thrombolysis. This study suggests a direct relation between improvement of regional left ventricular function and the greater infarct-related artery patency rate achieved by rt-PA compared with streptokinase.

[Behavior of arterial pressure during administration of intravenous streptokinase, in patients with acute myocardial infarct]

OBJECTIVE

To evaluate the effect on blood pressure (BP) of intravenous (IV) streptokinase (SK) in patients (PTS) with acute myocardial infarction (AMI).

DESIGN

Retrospective study with analysis of BP registers ten minutes before and during SK infusion.

SETTING

PTS admitted to the Coronary Care Unit (CCU) of Santo António Hospital, Oporto.

PATIENTS

Thirty-eight male PTS, average ages of 54, ranging from 38 to 67, AMI confirmed, and criteria to thrombolytic therapy. One patient was excluded on account of persistent hypotension since admission.

MATERIAL AND METHODS

IV infusion of 1,500,000 U of SK over 60 minutes, preceded by 200 mg IV of prednisolone. BP and heart rate (HR) were evaluated with a Datascope Accutorr 1A set. The lowest value of the systolic BP (SBP) recorded ten minutes before SK infusion was considered the baseline value. We valued the reduction of SBP above 15%, defining its fall as the difference between the baseline value and the minimum value of SBP recorded during the infusion. Hypotension was defined to SBP values below 90 mmHg.

MAIN RESULTS

The SBP fall was 40.4 +/- 22.1 mmHg (range 9 to 102), having been recorded the minimum value at 22.9 +/- 10.9 minutes. It was accompanied by diastolic BP (DBP) fall of 30.6 +/- 18.9 mmHg (range -2 to 76) and by a HR increasing from 76.2 +/- 13.7 beats/min. to 80.8 +/- 14.1 beats/min. (p less than 0.01). In 86% of the PTS this fall was transient, lasting 8.9 +/- 6.3 minutes, and was corrected by slowing or stopping the infusion for a few minutes and placing the patient in Trendelenburg position. Two PTS needed sympaticomimetic amines because of persistent BP reduction despite the previous measures. 92% of the PTS had a SBP fall higher than 15% in relation to the baseline value. The SBP was kept over 90 mmHg in 20 PTS (54%); hypotension was recorded in the remaining 14 PTS (38%), and in 10 (27%) of these the SBP fell below 80 mmHg. We couldn't prove that the infarction location and the extension of the ischemic lesion had influenced this BP fall.

CONCLUSION

The BP reduction during treatment with high doses of SK deserves some attention because, although transient and easily reversible, it is frequent and sometimes significative. It demands then careful monitoring in order to avoid the hypoperfusion to the ischemic myocardium, that could jeopardize the potential benefits of reperfusion in the reduction of infarction area, the main objective of the thrombolytic treatment.