Reocclusion three months after successful thrombolytic treatment of acute myocardial infarction with anisoylated plasminogen streptokinase activating complex

Thirty consecutive patients with acute myocardial infarction (AMI) were treated with anisoylated plasminogen streptokinase activating complex (APSAC) within 4 hours after onset of symptoms. After 1.5 and 48 hours, patency of the infarct-related vessel and the quantitative degree of residual diameter stenosis were studied by selective coronary angiography. Ventriculograms were made to determine the global left ventricular ejection fraction. Patients showing patency at 48 hours were reevaluated angiographically after 3 months. At 1.5 and 48 hours after APSAC administration patent vessels were demonstrated in 65 and 69% of patients, respectively. Mean residual stenosis decreased significantly from 56 +/- 11% at 1.5 hours to 46 +/- 13% at 48 hours (p less than 0.01). Patients not responding to thrombolytic therapy showed significant deterioration of the left ventricular function during the first 48 hours after AMI. Side effects were minor and mainly associated with invasive procedures. Despite adequate oral anticoagulation, angiographically documented reocclusion at 3 months amounted to 28%. Reocclusion, however, was neither associated with clinically documented reinfarction, nor with a decrease in the left ventricular ejection fraction. Our study shows that APSAC is an effective thrombolytic agent in AMI but that late reocclusion may occur. Oral anticoagulants appear to be less effective in the prevention of reocclusion in the treatment regimen after thrombolysis.

Anistreplase: a novel thrombolytic agent for acute myocardial infarction

Anistreplase, a modified congener of streptokinase, is a recently approved thrombolytic agent used in the treatment of acute myocardial infarction (AMI). Clinical studies have demonstrated anistreplase to be equally efficacious as intracoronary streptokinase when given within four hours of the onset of chest pain. Thirty units, given as a single bolus intravenous injection, result in reperfusion rates of approximately 60-70 percent. The adverse-effect profile of anistreplase compares favorably with that of streptokinase, with hemorrhagic complications being the most serious. Anistreplase has two distinct advantages over both streptokinase and alteplase: (1) it can be administered as a single bolus intravenous injection and (2) it has a longer half-life which may result in decreased reocclusion rates. Anistreplase therapy is associated with reductions in both short- and long-term mortality and has been shown to preserve left ventricular function. A large, long-term, comparative clinical trial (Third International Study of Infarct Survival or ISIS-III) investigating morbidity and mortality rates with streptokinase, alteplase, and anistreplase is ongoing, as is a direct comparative study against alteplase alone (TEAM-3, Multicenter Thrombolytic Trials of Eminase in Acute Myocardial Infarction).

Thrombolytic therapy in acute myocardial infarction

Recombinant tissue-type plasminogen activator (rt-PA), streptokinase (SK), and anisoylated plasminogen-streptokinase activator complex (APSAC) have salutary effects on mortality when administered to patients with evolving acute myocardial infarction (MI). Studies suggest that intravenous rt-PA is more effective in reperfusing occluded infarct-related arteries than SK, and the results of ongoing studies directly comparing the influence of SK and rt-PA on mortality are awaited. The clinical role of agents such as APSAC, urokinase, and pro-urokinase, used alone or in combination, remains to be determined. It is evident that a variety of thrombolytic agents will be effective, and variables such as ease of administration, pharmacokinetics, fibrin specificity, effects on blood viscosity, and incidence of adverse effects need to be assessed to determine which agents are the most suitable for clinical use. There is an increased risk of bleeding at vascular puncture sites with all thrombolytic agents. Current indications for thrombolytic therapy include ischemic chest pain of at least 30 min duration that is unrelieved by nitroglycerin and is associated with ST-segment elevations of at least 0.1 mV in two contiguous electrocardiographic leads. Such therapy is usually reserved for patients less than 75 years old who are not at increased risk for bleeding and whose chest pain began less than 4-6 prior to treatment. Trials are under way to determine whether patients with shorter pain duration, transient ST-segment changes (ie, unstable angina patients), chest pain associated with ST-segment depressions or T-wave inversions (ie, non-Q-wave infarction patients), or patients whose pain began more than 4 to 6 h earlier will benefit from early thrombolytic therapy. Other factors such as patient age, the likelihood of the diagnosis of MI, and the estimated risk of bleeding should also be considered. The findings of available major randomized trials indicate that early invasive procedures are generally unnecessary and that meticulous care must be exercised in the selection and management of patients subjected to thrombolytic therapy.

Optimised function for determining time to peak creatine kinase and creatine kinase-MB as non-invasive reperfusion indicators after thrombolytic therapy in acute myocardial infarction

STUDY OBJECTIVE

The aim of the study was to investigate the use of an optimised function to approximate and interpolate the time course of serum creatine kinase and creatine kinase-MB values after thrombolytic therapy in acute myocardial infarction.

DESIGN

A three parameter interpolating function was developed which approximates the time course of serum enzyme levels. In the proposed function, time to peak creatine kinase and maximum of creatine kinase determined from raw data were used as starting parameters of the non-linear interpolation routine, thus providing ideal starting conditions for the iteration. The efficacy of the function was compared with that of three other functions cited in published reports (log-normal distribution function, modified gamma density function, three compartment function).

SUBJECTS

Serum enzyme data from 20 patients with acute myocardial infarction were used in the comparisons. The patients have all been treated with anisoylated plasminogen streptokinase activator complex.

RESULTS

In comparison with the other models, deviations of the experimental model function from the raw data were minimal. The fit remained stable for time intervals between blood samples of up to 6 h. CONCLUSIONS - Due to its numerical stability, the function outlined in this study is suitable for large clinical reperfusion trials. In the case of uncomplicated infarctions without thrombolytic therapy, the area under the creatine kinase activity curve could be directly calculated in terms of maximum activity and time to peak.

[Anisoylated plasminogen streptokinase complex during the acute phase of myocardial infarction. Results of a multicenter double-blind study versus heparin]

Two hundred and thirty-one patients admitted to hospital within 5 hours of the onset of symptoms of a primary myocardial infarction were randomised into 2 groups: one received thrombolytic therapy [anisoylated plasminogen streptokinase activator complex (APSAC): 30 IU in 5 minutes] and the other was given conventional heparin therapy (5,000 IU). Heparin was given to both groups 4 hours later (500 IU/kg/day); the APSAC (N = 119) was identical with respect to age, location of infarct, Killip classification, delay before randomisation (188 +/- 62 minutes). Coronary angiography and ventriculography were performed after 3.4 +/- 1.2 days, and angioscintigraphy and myocardial scintigraphy after 19 +/- 2.5 days to determine the size of the infarct and the quality of left ventricular function. Coronary patency was much higher in the APSAC group (77%) than the heparin group (37%) (p less than 0.001). The angiographic ejection fraction was significantly greater in the thrombolytic group than in the heparin group (53 +/- 13% vs 47 +/- 12%, p less than 0.002), the difference being statistically significant in the anterior and inferior infarct subgroups. At the third week, the difference remained significant in the anterior infarct subgroup: a 31 per cent reduction in necrosed myocardial mass was observed in the APSAC group (33% in anterior infarcts: p less than 0.05 and 16% in inferior infarcts: NS). The limitation of infarct size explained the smaller reduction in left ventricular systolic function (r = 0.73; p less than 0.01). The hospital and one year mortality was comparable in the two groups which was not surprising given the small number of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Tolerance and complications in a multicenter trial of intravenous APSAC and intracoronary streptokinase in acute myocardial infarction

Adverse events data of a randomized, multicenter, angiographically controlled trial of intracoronary streptokinase and intravenous anistreplase, or anisoylated plasminogen streptokinase activator complex (APSAC) are presented. The frequency of severe adverse events is similar for streptokinase and anistreplase; no unexpected adverse experiences were reported with either drug. The most frequently encountered side effect was bleeding, overwhelmingly from the groin puncture site from angiography.

Variability of thrombolytic coronary reperfusion: an angiographic study of streptokinase and anistreplase

A total of 1,615 angiographic readings in 240 patients with acute myocardial infarction were analyzed from a randomized trial of intravenous anistreplase (Eminase), also known as anisoylated plasminogen streptokinase activator complex (APSAC), versus intracoronary streptokinase. Coronary arteriography was performed at baseline and at 15, 30, 45, 60, 75, and 90 minutes after drug infusion. Coronary flow in the infarct-related artery was defined using the TIMI criteria. Some serial change in perfusion was noted in 25% of the total patient population and in 49% of all reperfusion patients. Complete loss of perfusion (grade 2 or 3 to grade 0 or 1) occurred in 35% of all reperfused patients. Half of these patients ultimately developed complete loss of perfusion at the study endpoint. All of these changes in flow were statistically more common for the circumflex coronary artery and early treatment (less than 4 h), but did not differ for anistreplase or streptokinase. We conclude that frequent alterations in coronary blood flow occur early during reperfusion therapy and that these findings may explain reports with varying results of thrombolytic therapy. Any angiographic assessment of thrombolytic drug efficacy should take these variations as well as interobserver variability into account.

Pharmacology of anistreplase

Eminase (anistreplase), or anisoylated plasminogen streptokinase activator complex (APSAC), is a reversibly inactivated lys-plasminogen-streptokinase activator complex that is given rapidly over a period of 2-5 minutes, and has a half-life in the circulation of 90-105 min. Eminase represents a significant advance in drug design for therapeutic thrombolysis based on convenience in administration, high gradient (especially initially) for diffusion into thrombus, improved fibrin binding, ability to lyse fibrin rapidly, improved stability in the circulation, long duration of action, and production of an antithrombotic state.

Summary of U.S. clinical trials program for evaluation of anistreplase

Because the reestablishment of coronary blood flow is believed to be central to the benefit of thrombolytic therapy, the U.S. evaluation program of anistreplase has focused on reperfusion, patency, and reocclusion comparisons with approved thrombolytic regimens, including (1) intracoronary streptokinase (completed) (TEAM-I), (2) intravenous streptokinase (completed) (TEAM-II), and (3) intravenous tissue plasminogen activator complex or alteplase (tPA, ongoing) (TEAM-III). The TEAM trials have established that anistreplase possesses similar reperfusion efficacy to intracoronary streptokinase, if given within 4 h, but is much easier to administer; comparisons with currently approved intravenous agents, streptokinase, and tissue plasminogen activator (tPA) have been completed and are being analyzed or are underway; reocclusion and reinfarction rates are low; safety is good, and similar to that of streptokinase; and mortality rates have been low with treatment, consistent with beneficial reports from randomized trials. Based on overall efficacy, ease of administration, and safety, anistreplase has been shown to be a promising agent for treatment of acute myocardial infarction.

Angiographic assessment of patency and reocclusion: preliminary results of the Dutch APSAC Reocclusion Multicenter Study (ARMS)

The main objective of the ARMS (APSAC Reocclusion Multicenter Study) trial was to obtain patency and reocclusion data. In an open multicenter study, a total of 156 patients were treated with 30 U of anistreplase or anisoylated plasminogen streptokinase activator complex (APSAC) within 4 h after onset of pain. Patency of the infarct-related vessel was assessed by coronary angiography performed 90 minutes after anistreplase administration. In those patients with a patent infarct-related vessel at 90 min, repeat coronary angiography was performed at 24 h to assess the reocclusion rate. Two independent cardiologists evaluated the angiograms and scored the coronary artery perfusion of the infarct-related vessel. The preliminary data of the first 148 patients indicate that the patency rate at 90 min was 73-75% and the reocclusion rate at 24 h was 4%. This patency rate corresponds with previous studies. The low reocclusion rate is noteworthy and probably reflects the prolonged action of anistreplase.

The APSAC interventional mortality study (AIMS) trial: mortality data

The anistreplase (anisoylated plasminogen streptokinase activator complex or APSAC) intervention mortality study was designed as a double-blind, placebo-controlled study to test the effectiveness of anistreplase, 30 U administered intravenously within the first 6 hours of acute myocardial infarction. The primary endpoint of the study was mortality of all causes at 30 days and 1 year. Within 30 days, there were 77 deaths with placebo (17.8%) and 40 deaths (6.5%) with anistreplase, an odds reduction of 50.5% (p = 0.0006). By the end of one year, there had been a total of 113 deaths (17.8%) with placebo and 69 deaths (11.1%) with anistreplase, an odds reduction of 42.7% (p = 0.0007).

Effects on infarct size and left ventricular function of early intravenous injection of anistreplase in acute myocardial infarction. The APSIM Study Investigators

A total of 231 patients suffering from a first acute myocardial infarction were randomly allocated within 4 hours following the onset of symptoms either to anistreplase or anisoylated plasminogen streptokinase activator complex (APSAC), 30 U over 5 minutes, or to conventional heparin therapy, 5000 IU in bolus injection. Heparin was reintroduced in both groups 4 h after initial therapy at a dosage of 500 IU/kg per day. A total of 112 patients received anistreplase and 119 received heparin within a mean period of 188 +/- 62 min following the onset of symptoms. Infarct size was estimated from single photon emission computerized tomography and expressed in percentage of the total myocardial volume. The patency rate of the infarct-related artery was 77% in the anistreplase group and 36% in the heparin group (p less than 0.001). Left ventricular ejection fraction determined from contrast angiography was significantly higher in the anistreplase group than in the heparin group (6 absolute percentage point difference). A significant 31% reduction in infarct size was found in the anistreplase group (33% for the anterior wall infarction subgroup [p less than 0.05] and 16% for the inferior wall infarction subgroup, NS). A close inverse relation was found between the values of left ventricular ejection fraction and infarct size (r = -.73, p less than 0.01). In conclusion, early infusion of anistreplase in acute myocardial infarction produced a high early patency rate, a significant limitation of infarct size, and a significant preservation of left ventricular systolic function, mainly in the anterior wall infarctions.

The safety of anistreplase from the placebo-controlled AIMS study (anistreplase Intervention Mortality Study). The AIMS Study Group

In the anistreplase, or anisoylated plasminogen streptokinase activator complex (APSAC) Intervention Mortality Study (AIMS), 1,258 patients with acute myocardial infarction were randomized in a parallel, double-blind, placebo-controlled mortality study in which they received either anistreplase or placebo, followed by anticoagulation therapy. Data on all adverse clinical events were recorded, regardless of their clinical significance or possible relation to therapy. There was a similar frequency of such events in both groups (anistreplase 80.4%, placebo 76.0%, difference not significant). Cardiovascular events included more reports of bradycardia, idioventricular rhythm, and hypotension in the anistreplase group, and a higher incidence of cardiac arrest, ventricular fibrillation, complete heart block, and pericarditis in the placebo group. Hemorrhagic events occurred in 13.8% of patients in the anistreplase group compared with 4.1% of patients in the placebo group. Most of these events consisted of bleeding or bruising around the puncture sites. There was a low incidence of allergic events after administration of both anistreplase and placebo. Thirteen cerebrovascular events (8 strokes and 5 transient ischemic episodes) were reported in the anistreplase group, compared with 5 in the placebo group (5 and 0, respectively). The mean systolic and diastolic pressures were significantly lower (by 5-10 mmHg) in patients in the anistreplase group during the first 24 hours after dosing. There were no significant differences in temperature and pulse rate between the two groups. The incidence of chest pain during the first 4- to 24-h period was lower in the anistreplase-treated patients than in the placebo group. The frequency of in-hospital reinfarction was higher in anistreplase-treated patients compared with patients given placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term effects of intravenous anistreplase in acute myocardial infarction: final report of the AIMS study. AIMS Trial Study Group

In a randomised, double-blind study 1258 patients were allocated to receive either anistreplase (anisoylated plasminogen streptokinase activator complex [APSAC], 'Eminase') or placebo within 6 h of onset of suspected acute myocardial infarction. At 30 days, 40 (6%) of 624 patients on anistreplase had died, compared with 77 (12%) of 634 patients on placebo (odds reduction 50.5%). On long-term follow-up a survival benefit was still observed: at 12 months, 69 (11%) patients treated with anistreplase had died, compared with 113 (18%) patients given placebo (odds reduction 43%; p = 0.0007, 95% confidence interval 21-59%). This effect on mortality was not related to time between onset of symptoms and treatment or to any patient characteristic. Site of infarction and age were the most important influences on 1-year survival in both treatment groups; tachycardia (over 100 beats/min) on admission and previously diagnosed ischaemic heart disease were also associated with increased risk. Major complications of acute myocardial infarction were less frequent in patients treated with anistreplase than in controls. As for other thrombolytic agents, haemorrhage was more common, but usually minor. These findings indicate that anistreplase is an effective and acceptably safe thrombolytic with long-term survival benefits for patients with acute myocardial infarction.

Angiographic patency study of anistreplase versus streptokinase in acute myocardial infarction

128 patients with acute myocardial infarction of duration 6 h or less were randomised in double-blind fashion to receive 30 U anistreplase over 5 min or 1.5 MU streptokinase over 1 h, both intravenously. Angiographic patency was assessed 90 min and 24 h from the start of therapy. 55% of patients who received anistreplase and 53% of patients who received streptokinase had patent infarct-related arteries (TIMI grade 2-3) at 90 min (95% CI 42-68% and 40-66%, respectively). At 24 h 81% and 87.5% of arteries were patent respectively (95% CI, 71-91% and 83.5-91.5%). Time to therapy had no significant effect on patency rates. There was one early reocclusion within 24 h in each treatment group and clinical evidence of reocclusion was recorded between 24 h and hospital discharge in a further 5 patients (streptokinase 3, anistreplase 2). With these regimens, therefore, anistreplase and streptokinase gave the same patency rates.

[Coronary reperfusion by anistreplase (Eminase) used intravenously during the acute phase of myocardial infarction]

Coronary recanalisation rate is one of the parameters utilized to evaluate the effectiveness of a thrombolytic agent. This parameter can only be measured when the occlusion and reopening of the coronary artery involved are demonstrated by angiography. Moreover, this type of study enables the kinetics of drug activity to be accurately determined. When injected intravenously in doses of 30 units less than four hours after the onset of chest pain and when studied by this method, Eminase produces recanalisation in more than 60 per 100 of the cases. The time elapsed between injection and action is 45 minutes on average. The risk of early reocclusion is low (about 5%). The recanalisation rate obtained with Eminase is similar to that obtained with intracoronary streptokinase.

Improved left ventricular function in myocardial infarction following intravenous thrombolytic therapy with acylated plasminogen activator

Forty-six patients with acute myocardial infarction (MI) were treated within three hours of the onset of chest pain with an intravenous bolus (IV) of 30 units of anisolated plasminogen activator streptokinase complex (APSAC). Reperfusion was detected in 31 patients (67%) by clinical, electrocardiographic, and enzymatic criteria. The mean time elapsed between the onset of the chest pain to thrombolytic therapy was 114 +/- 53 minutes. Left ventricular ejection fraction (LVEF) was significantly better in patients with anterior and inferior myocardial infarction who had successful reperfusion, as compared with those who did not (48.8 +/- 13.0 vs 35.3 +/- 10.9, p less than 0.05 and 59.7 +/- 12.6 vs 47.9 +/- 15.3, p less than 0.05, respectively). The rate of reocclusion within three weeks was 22%. The overall one-year mortality was 4%. There were no serious adverse reactions following the thrombolytic treatment. Thus bolus IV injection of 30 units of APSAC is both safe and effective in preserving left ventricular function when given early in the course of acute myocardial infarction.

[Intra-arterial thrombolytic therapy of lower limb ischemia]

Between 1984 and 1989, 35 patients with recent arterial or graft occlusions have been treated with intra-arterial infusion using sequential association of Urokinase (U.K.) and Lys-Plasminogen. Occlusion was thrombotic in 68.5% of the cases ans embolic in 31.5%, involving 28 native arteries and 7 bypass grafts. The mean duration was 16 days (2 to 90). Continuous infusion of U.K.: 84,000 U.I./H and bolus of Lys-Plasminogen 15 microKatals every 30 minutes were delivered through a catheter embedded into the clot. Intra-venous heparin was always associated. The mean duration of lytic drug infusion was 8 H. Complementary arterial reconstruction by vascular surgery of percutaneous transluminal angioplasty was performed in 23% of the patients. Patients with recent alimentary tract bleeding, hemorragic stroke in the last six months or severe high blood pressures were contra-indicated. Complete lysis was obtained in 23 cases (66%), partial lysis in 7 (20%) and no lysis in 5 (14%). The clinical result was excellent in 24 cases (68.5%), good in 3 (8.5%) and bad in 8 (23%) in which amputation was always necessary. 5 local hematoma (14%) treated by surgery or transfusion and one death (3%) due to neurological complication occurring 24 hours after the end of the procedure were observed. The literature survey has shown that the results of low doses of Streptokinase (S.K.) local infusions were not better, and that higher doses of S.K. or U.K. delivered during a shorter infusion time increased the efficacy of lysis and decreased the rate of hemorragic complications. We have proposed the local thrombolytic treatment to the limb threatening ischemic cases when the traditional medical or surgical techniques where thought to be associated to a high risk of failure or complication. The specific indications are the acute or sub-acute ischemic situation due to atheromatous artery thrombosis, distal or old embolism where the Fogarty catheter is inefficient, and graft thrombosis. Severe acute ischemia with neurologic involvement are not good indications. Local thrombolysis can be successful on arterial occlusion even after one month duration.

[Pre-hospital thrombolysis]

Too few myocardial infarctions are thrombolysed, and the thrombolytic agent is usually administered too late. This situation can conceivably be improved by educating both physicians and patients, by promoting thrombolysis in all hospitals and by performing thrombolysis before admission. We report here our experience of pre-hospital thrombolysis with Eminase in the Val-de-Marne department. This preliminary study is just a small stone added to the big heap of small series of thrombolysis at home published throughout the world. But while the feasibility of pre-admission thrombolysis has been well demonstrated, its effectiveness remains to be accurately determined. Two studies involving large groups of patients are currently in progress: one in Seattle with the left ventricular function as principal criterion of judgment, the other in Europe (The European Myocardial Infarction Project) with mortality as main criterion of judgment. We must wait for the results of these studies to know whether pre-hospital thrombolysis will become the standard treatment of myocardial infarction and if so, to implement the relevant changes required in health structures.

[Study of survival using anistreplase (Eminase)]

Thrombolytic therapy has been one of the most important advances in the field of cardiovascular medicine. Several agents are available and research is continuing to develop new effective thrombolytics with a rapid onset of action. The efficacy of thrombolytic therapy can be evaluated by a number of criteria such as the reperfusion time, the incidence of coronary recanalisation, left ventricular function, and survival. Survival is certainly the parameter of choice for assessing any thrombolytic protocol. The aim of this paper is therefore to review the results of survival studies with Eminase, one of the new thrombolytic agents used in the treatment of acute myocardial infarction.

Body surface potential mapping to monitor the effects of thrombolytic therapy following acute myocardial infarction

The authors demonstrate the value of body surface potential mapping (BSPM) and a limited lead system in monitoring complete ECG evolution following myocardial infarction (MI) and the effects of thrombolytic therapy. They produced ST-segment isopotential maps, which indicate the site and extent of myocardial injury. Pathological Q wave maps were also produced, which intimate the extent of myocardial necrosis. Analysis of a sequence of maps recorded during the acute phase of MI revealed sudden changes attributed to reperfusion, reinfarction or "silent" events.

Safe use of thrombolysis in the elderly

Elderly individuals with acute myocardial infarction represent a high-risk population that may benefit the most from thrombolytic therapy. To date, studies with streptokinase, tissue plasminogen activator (t-PA), and APSAC have shown improved survival in patients up to age 80, although there was an increased risk for hemorrhagic complications. While a placebo-controlled trial is needed to confirm these findings in even older patients, careful screening of the individual should make thrombolysis safe and effective for selected patients in this age group.