Adverse long-term effects of reocclusion after coronary thrombolysis

Prolonged anticoagulation therapy adjunctive to aspirin after successful fibrinolysis: from early reduction in reocclusion to improved long-term clinical outcome

BACKGROUND

Long-term addition of antithrombotics (clopidogrel, anticoagulants) to aspirin has improved outcome after acute coronary syndromes. Data on the impact after fibrinolysis are scarce. In Antithrombotics in the Prevention of Reocclusion In COronary Thrombolysis-2 (APRICOT-2), adjunctive moderate-intensity coumarin (median international normalized ratio 2.6) conferred a marked reduction in 3-month reocclusion and ischemic events. Given the association between reocclusion and long-term outcome, we performed long-term clinical follow-up.

METHODS

Patients with thrombolysis in myocardial infarction (TIMI) 3 flow <48 hours after fibrinolysis for ST-elevation myocardial infarction were randomized to aspirin plus coumarin, with prolonged heparinization until the target international normalized ratio (2-3) was reached, or aspirin with standard heparinization. Three-month follow-up angiography (reocclusion rates 15% vs 28%) and long-term clinical follow-up (median 7.3 years, interquartile range 5.9-8.6 years) were performed.

RESULTS

Patients randomized to adjunctive anticoagulation (n = 123) received coumarin for a median of 280 days (113-387 days). Survival was 94% versus 88% in patients on aspirin alone (n = 128, P = .12). Infarct-free survival was 86% versus 71% (P = .01). Thrombolysis in myocardial infarction bleeding was 4% in both groups. Patients with reocclusion had impaired survival: 80% versus 94% (P < .01). In a multivariable model without reocclusion, combination therapy independently predicted survival (hazard ratio [HR] 0.36, 95% confidence interval [CI] 0.13-1.00) and infarct-free survival (HR 0.51, 95% CI 0.28-0.95). When adjusted for reocclusion, combination therapy did not predict outcome. Reocclusion independently predicted death (HR 2.56, 95% CI 1.02-6.43) and reinfarction.

CONCLUSIONS

Moderate-intensity oral anticoagulation added to aspirin improved 8-year clinical outcome after successful fibrinolysis. The beneficial effect was largely attributed to a reduction in reocclusion, which independently predicted death and reinfarction. This study provides a mechanistic rationale for prolonged adjunctive anticoagulation after fibrinolysis.

Sustained coronary patency after fibrinolytic therapy as independent predictor of 10-year cardiac survival Observations from the Antithrombotics in the Prevention of Reocclusion in COronary Thrombolysis (APRICOT) trial

BACKGROUND

Whether late coronary patency after myocardial infarction has prognostic impact independent of left ventricular function remains a matter of debate. Reocclusion rates in the first year after fibrinolysis vary between 20% and 30%. Of all reocclusions, about 30% present as clinical reinfarction, associated with a 2-fold-increased risk of mortality. The clinical impact of reocclusion that presents without reinfarction has not been studied; but an association has been demonstrated with impaired contractile recovery of left ventricular function, the strongest prognosticator of long-term outcome. We therefore studied the impact of 3-month coronary patency after successful fibrinolysis on 10-year cardiac survival.

METHODS

In the APRICOT-1 trial, 248 ST-elevation myocardial infarction patients with an open infarct artery 24 hours after fibrinolysis had 3-month repeated angiography. Ten-year clinical follow-up was complete in 99.6%.

RESULTS

The reocclusion rate was 29% (71/248). Of these reocclusions, 24% presented as clinical reinfarction (17/71). Cardiac survival at 10 years was 73% in patients with a reoccluded infarct artery and 88% in patients with sustained patency (P < .01). This difference was also present in patients in whom reocclusion was only detected as a result of systematic repeated angiography, that is, in the absence of reinfarction or ischemic symptoms between angiograms (70% vs 86%, P < .03). Multivariable analysis identified sustained patency at 3-month angiography as independent predictor of 10-year cardiac survival (hazard ratio 2.10, 95% CI 1.10-4.02) together with left ventricular ejection fraction.

CONCLUSIONS

Sustained infarct artery patency in the first 3 months after successful fibrinolysis is a strong predictor of 10-year cardiac survival, independent of left ventricular function. Notably, this also holds true when reocclusion occurs without signs of clinical reinfarction or recurrent ischemia. Therefore, future preventive strategies should also focus on "clinically silent" reocclusions. Additional studies on better antithrombotic regimens and the combination with a routine invasive strategy early after successful fibrinolysis are warranted.

High-grade infarct-related stenosis after successful thrombolysis: strong predictor of reocclusion, but not of clinical reinfarction

BACKGROUND

After successful thrombolysis, a high-grade stenosis at 24-hour angiography is strongly predictive of reocclusion and is often believed to result in high reinfarction rates. However, routine angioplasty did not reduce death or reinfarction in past trials. Systematic angiographic follow-up shows that reocclusion often occurs without clinical reinfarction. This study investigates whether the increased risk for reocclusion associated with a high-grade lesion translates into impaired clinical outcome.

METHODS

In the ischemia-guided Antithrombotics in the Prevention of Reocclusion in COronary Thrombolysis (APRICOT-1) trial, 240 patients with ST-elevation MI who had an open infarct artery 24 hours after thrombolysis had 3-month repeat angiography to assess reocclusion, with clinical follow-up at 3 months and 3 years.

RESULTS

On the basis of the optimal discriminative stenosis severity, the reocclusion rate was 40% (47/118) in patients with a high-grade residual stenosis and 16% (20/122) in patients with a low-medium-grade lesion (risk ratio [RR], 2.43; 95% CI, 1.54-3.84; P <.01). Three-month death and reinfarction rates did not differ: 6% (7/118) versus 9% (11/122; RR, 0.66; 95% CI, 0.26-1.64; P = not significant). Systematic angiographic follow-up revealed that reocclusion of a high-grade lesion occurred in the absence of clinical reinfarction in 85% (40/47) of patients, as compared with 45% (9/20) in patients with a low-medium-grade stenosis (RR, 1.89; 95% CI, 1.15-3.12; P <.01). Despite an independent association with reocclusion, a high-grade stenosis was not predictive of either short- or long-term death and reinfarction.

CONCLUSIONS

After successful thrombolysis and adopting an ischemia-guided revascularization strategy, patients with a high-grade stenosis experience death/reinfarction rates similar to that of patients with a low-medium-grade lesion. This is true despite a 2- to 3-fold higher risk for reocclusion. The finding that reocclusion of a high-grade lesion often occurs without clinical reinfarction explains the absence of a relationship between a severe stenosis and death/reinfarction. Appreciation of these observations may contribute to an optimal design of a future randomized trial to re-evaluate the impact of a routine invasive strategy.

Routine invasive strategy within 24 hours of thrombolysis versus ischaemia-guided conservative approach for acute myocardial infarction with ST-segment elevation (GRACIA-1): a randomised controlled trial

BACKGROUND

In patients with ST-segment elevated myocardial infarction (STEMI), early post-thrombolysis routine angioplasty has been discouraged because of its association with high incidence of events. The GRACIA-1 trial was designed to reassess the benefits of an early post-thrombolysis interventional approach in the era of stents and new antiplatelet agents.

METHODS

500 patients with thrombolysed STEMI (with recombinant tissue plasminogen activator) were randomly assigned to angiography and intervention if indicated within 24 h of thrombolysis, or to an ischaemia-guided conservative approach. The primary endpoint was the combined rate of death, reinfarction, or revascularisation at 12 months. Analysis was by intention to treat.

FINDINGS

Invasive treatment included stenting of the culprit artery in 80% (199 of 248) patients, bypass surgery in six (2%), non-culprit artery stenting in three, and no intervention in 40 (16%). Predischarge revascularisation was needed in 51 of 252 patients in the conservative group. By comparison with patients receiving conservative treatment, by 1 year, patients in the invasive group had lower frequency of primary endpoint (23 [9%] vs 51 [21%], risk ratio 0.44 [95% CI 0.28-0.70], p=0.0008), and they tended to have reduced rate of death or reinfarction (7% vs 12%, 0.59 [0.33-1.05], p=0.07). Index time in hospital was shorter in the invasive group, with no differences in major bleeding or vascular complications. At 30 days both groups had a similar incidence of cardiac events. In-hospital incidence of revascularisation induced by spontaneous recurrence of ischaemia was higher in patients in the conservative group than in those in the invasive group.

INTERPRETATION

In patients with STEMI, early post-thrombolysis catheterisation and appropriate intervention is safe and might be preferable to a conservative strategy since it reduces the need for unplanned in-hospital revascularisation, and improves 1-year clinical outcome.

Outcomes of thrombolytic therapy for acute myocardial infarction in women

Coronary artery disease is the leading cause of mortality in women older than 50 years of age. Thrombolytic therapy substantially reduces mortality in both women and men with ST-elevation acute myocardial infarction. However, the mortality risk reduction is somewhat lower in women, in spite of similar rates of successful coronary reperfusion after thrombolytic therapy in women and men. Hemorrhagic complications including stroke and other major bleeding appear to be more common in women, particularly elderly women. The risk of reinfarction after thrombolytic therapy also is greater in women compared with men. Because of the higher complication rates, women should be monitored closely after thrombolytic therapy. However, this lifesaving treatment should not be withheld or delayed in women when indicated.

Power thrombectomy in acute ischemic coronary syndromes

Intracoronary thrombi are commonly found in patients with acute coronary syndromes. A large thrombus burden or a platelet-rich thrombus frequently resists pharmacologic therapy ("thrombolytic ceiling"). In such cases restoration of adequate antegrade coronary flow necessitates application of a mechanical force. Power thrombectomy is a revascularization strategy incorporating a mechanical device for removal of occlusive coronary thrombi in conjunction with or following administration of either platelet glycoprotein IIb/IIIa receptor inhibitors or thrombolytic agents, or both. Mechanical devices for power thrombectomy include ultrasound sonication, rheolytic thrombectomy (Angiojet), laser, transluminal extraction catheter, aspiration catheter, and to a limited extent, balloon angioplasty. In acute coronary syndromes the strategy of power thrombectomy aims to achieve the clinical advantages of more nearly complete vessel patency, improved antegrade flow, and enhanced preservation of myocardial tissue.

The effect of statin therapy on ventricular late potentials in acute myocardial infarction

AIMS

To determine whether early statin therapy in acute myocardial infarction has any effect on ventricular late potentials which are considered as a noninvasive tool for evaluation of arrhythmogenic substrate.

METHODS AND RESULTS

Study population consisted of prospectively enrolled 72 patients presenting with acute myocardial infarction (<6 h). Thirty-four of the patients were randomized to pravastatin (40 mg/day) on admission irrespective of lipid levels. All patients received thrombolytic therapy. Signal-averaged ECG recordings were obtained serially prior to thrombolytic therapy, 48 h after and 10 days later. Late potentials were defined as positive if signal-averaged ECG met at least two of Gomes criteria: filtered total QRS duration >114 ms, root mean square voltage of the last 40 ms of the QRS <20 mV, or the duration of the terminal low (<40 mV) amplitude signals >38 ms. Changes observed in signal-averaged ECG recordings after thrombolysis were evaluated statistically with regard to statin usage. There were no significant differences between the clinical characteristics of the two randomized groups. There was a significant decrease in the rates of late potentials between the first and third signal-averaged ECG recordings after thrombolytic therapy in pravastatin group. Pravastatin group also had lower incidence of ventricular arrhythmias compared with control group (26 vs. 63%, P=0.021). The in-hospital cardiovascular event rates were also lower in statin group.

CONCLUSION

Early use of pravastatin reduces the incidence of late potentials following thrombolytic therapy in acute myocardial infarction. Statin therapy also seems to be reducing the incidence of in-hospital ventricular arrhythmias. These beneficial effects of statins might be explained through prevention of new myocardial ischemic episodes due to early plaque stabilization or regulation of endothelial and platelet functions.

Acute myocardial infarction complicated by early onset of heart failure: safety and feasibility of interhospital transfer for coronary angioplasty. Subanalysis of Killip II-IV patients from the PRAGUE-1 study

OBJECTIVE

The objective of this study is to assess the feasibility and safety of interhospital transfer (within up to 60 minutes) for primary/rescue coronary angioplasty of patients with myocardial infarction (AMI) complicated by an early onset of acute heart failure (AHF) admitted to a community hospital without PCI facilities.

DESIGN AND PATIENTS

From the multicenter randomized PRAGUE-1 study, a subgroup of 66 patients with AMI complicated by AHF on the first presentation to the community hospital were retrospectively analyzed. Group A patients (n = 21) were treated on site in community hospitals using thrombolysis (streptokinase), group B patients (n = 20) were transported with thrombolytic infusion to a PCI center for coronary angioplasty, and group C patients (n = 25) were immediately transported to a PCI center for primary angioplasty without thrombolysis.

RESULTS

No patient died during transportation. One group B patient developed ventricular fibrillation during transfer. The time delay from the onset of chest pain to reperfusion was > 142 minutes, and 253 and 251 minutes in groups A, B, and C, respectively. Hospital stay (16 vs 11 vs 10 days, P = NS) was shorter in the angioplasty groups. Transported patients (groups B, C) displayed a significant decrease in heart failure progression within the first 24 hours after treatment (48% vs 15% vs 8%, P < 0.05). The combined end point, i.e., mortality + nonfatal reinfarction (43% vs 25% vs 8%, P < 0.05), was significantly less frequent in the coronary angioplasty group.

CONCLUSIONS

Interhospital transfer for coronary angioplasty of patients with AMI complicated by an early onset of AHF is feasible and safe. Transport for angioplasty may even reduce the risk of heart failure progression and improve clinical outcome compared to immediate thrombolysis in the nearest community hospital.

Aspirin plus coumarin versus aspirin alone in the prevention of reocclusion after fibrinolysis for acute myocardial infarction: results of the Antithrombotics in the Prevention of Reocclusion In Coronary Thrombolysis (APRICOT)-2 Trial

BACKGROUND

Despite the use of aspirin, reocclusion of the infarct-related artery occurs in approximately 30% of patients within the first year after successful fibrinolysis, with impaired clinical outcome. This study sought to assess the impact of a prolonged anticoagulation regimen as adjunctive to aspirin in the prevention of reocclusion and recurrent ischemic events after fibrinolysis for ST-elevation myocardial infarction.

METHODS AND RESULTS

At coronary angiography <48 hours after fibrinolytic therapy, 308 patients receiving aspirin and intravenous heparin had a patent infarct-related artery (Thrombolysis In Myocardial Infarction [TIMI] grade 3 flow). They were randomly assigned to standard heparinization and continuation of aspirin alone or to a 3-month combination of aspirin with moderate-intensity coumarin, including continued heparinization until a target international normalized ratio (INR) of 2.0 to 3.0. Angiographic and clinical follow-up were assessed at 3 months. Median INR was 2.6 (25 to 75th percentiles 2.1 to 3.1). Reocclusion (< or =TIMI grade 2 flow) was observed in 15% of patients receiving aspirin and coumarin compared with 28% in those receiving aspirin alone (relative risk [RR], 0.55; 95% CI 0.33 to 0.90; P<0.02). TIMI grade 0 to 1 flow rates were 9% and 20%, respectively (RR, 0.46; 95% CI, 0.24 to 0.89; P<0.02). Survival rates free from reinfarction and revascularization were 86% and 66%, respectively (P<0.01). Bleeding (TIMI major and minor) was infrequent: 5% versus 3% (P=NS).

CONCLUSIONS

As adjunctive to aspirin, a 3-month-regimen of moderate-intensity coumarin, including heparinization until the target INR is reached, markedly reduces reocclusion and recurrent events after successful fibrinolysis. This conceptual study provides a mechanistic rationale to further investigate the role of prolonged anticoagulation after fibrinolytic therapy.

Safety of coronary stenting early after thrombolysis in patients with acute myocardial infarction: one- and six-month clinical and angiographic evolution

To determine the feasibility and safety of early posthrombolysis coronary stenting and the incidence of further reocclusion, we followed 99 consecutive patients with acute myocardial infarction thrombolyzed with rt-PA 2.0 +/- 0.8 hr after onset. Culprit artery was stented 14.0 +/- 7.0 hr after thrombolysis. All patients underwent clinical and angiographic follow-up at 1 and 6 months. Angiographic success was achieved in 99% of cases. Neither major cardiac events nor bleeding or vascular complications occurred during hospital stay. At 30 days, no events occurred and normal flow persisted in all stented arteries. At 6 months, only one artery reoccluded (1%), resulting in a nonfatal reinfarction. Restenosis rate was 21%. Contribution of the infarcted area to left ventricular function significantly increased from baseline to 30-day and to 6-month evaluations. Thus, early posthrombolysis stenting is a safe strategy with a low reocclusion rate, which seems to allow functional recovery of the infarcted area. Further studies are necessary to define its impact on survival and cost-effectiveness.

Treating atherosclerosis: local drug delivery from laboratory studies to clinical trials

Treating only the specific section of the vascular bed that is diseased appears to make sense. Giving drugs systematically to treat perhaps only a few centimetres of affected artery carries with it the risk of systemic side effects and reduced efficacy consequent on low concentrations of agent at the site of the problem. There has thus been great interest since the early 1990s in local drug delivery. Initial targets were the thrombotic response to plaque disruption but the problems arising from the incidental damage inflicted by devices used in interventional cardiology and the pathological consequences of this, namely smooth muscle cell initiated intimal hyperplasia, soon became the focus of pre-clinical studies. Problems to be overcome were the low efficiency of delivery of drugs and the low retention rates. Solutions to these problems included the development of strategies to target drugs, through the use of antibodies directed at antigens newly released at the site of damage. As it became clear that stents were becoming central to the attainment of a better clinical response to intervention by their inherent physical properties, it also became obvious that stents could be used to deliver agents. Issues such as which stent, how to load the drug onto the stent and what drug to use to inhibit the unwanted pathobiological response are ongoing issues.

Treatment of reinfarction after thrombolytic therapy for acute myocardial infarction: an analysis of outcome and treatment choices in the global utilization of streptokinase and tissue plasminogen activator for occluded coronary arteries (gusto I) and assessment of the safety of a new thrombolytic (assent 2) studies

BACKGROUND

Early reinfarction after thrombolytic therapy is associated with adverse outcomes and increased mortality. Among patients with reinfarction in the 1992 Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO I) and the 1998 Assessment of the Safety of a New Thrombolytic (ASSENT 2) trials, we investigated temporal and regional differences in the use of repeat thrombolysis, revascularization (angioplasty and/or bypass surgery), or conservative measures and the outcomes of each management strategy.

METHODS AND RESULTS

Data from the 4% of patients (n=2301) who experienced reinfarction after thrombolytic therapy were studied. Baseline characteristics, 30-day mortality, and incidence of total and hemorrhagic strokes were compared among the 3 treatment groups. The 30-day mortality did not differ between the repeat thrombolysis and revascularization groups (P=0.72), and it was significantly lower among patients treated by these 2 strategies than in those treated conservatively (11% and 11% versus 28%, respectively; P<0.001). Stroke rates did not differ significantly between the 3 treatment strategies (P=0.49). From 1992 to 1998, the percentage of reinfarction patients treated with repeat thrombolysis decreased from 29.3% to 18.5% in US centers and from 51.4% to 41.9% in all other centers (P<0.001). In contrast, use of revascularization procedures increased from 33.5% to 47.9% in US centers and from 8.1% to 23.0% in all other centers (P<0.001).

CONCLUSIONS

Repeat thrombolysis and revascularization are associated with significantly lower mortality among reinfarction patients. Randomized trials are necessary to assess the exact risks and benefits of rethrombolysis versus interventional revascularization in this subset of high-risk patients presenting with reinfarction after thrombolytic therapy.

Antiplatelet therapy

Within the last few years antiplatelet therapy has developed exponentially, with new agents being tested in an increasing number of clinical scenarios. The mechanism of action of these newer agents and evidence of benefit is prevented in this review.

Overcoming thrombolytic resistance: rationale and initial clinical experience combining thrombolytic therapy and glycoprotein IIb/IIIa receptor inhibition for acute myocardial infarction

OBJECTIVES

We sought to review the emerging data and the clinical rationale for combining glycoprotein (GP) IIb/IIIa inhibitors with thrombolytic therapy for acute myocardial infarction (AMI).

BACKGROUND

Although thrombolytic therapy has been a major advance in the treatment of acute ST segment elevation MI, new single-bolus thrombolytic agents have been unable to break the "thrombolytic ceiling" in infarct-related artery (IRA) patency.

METHODS

Recent literature on GPIIb/IIIa inhibitors in acute coronary syndromes was reviewed.

RESULTS

A new approach toward improving current thrombolytic-antithrombotic regimens focuses on "targeted therapy" for each component of the occlusive coronary thrombus: fibrin, thrombin and platelets. For the fibrin component, front-loading and/or bolus dosing of plasminogen activators (PAs) has identified the currently available doses of tissue-type plasminogen activator (t-PA) and recombinant tissue-type plasminogen activator (r-PA). For the thrombin component, several recent trials have shown that lower doses of heparin improve the safety profile of the thrombolytic-antithrombotic regimen. For the platelet component, aspirin has been shown to be effective, but the GPIIb/IIIa inhibitors offer the potential for more effective platelet inhibition and improved clinical efficacy. The benefits of GPIIb/IIIa inhibition in reducing death, MI or urgent revascularization in the setting of percutaneous coronary intervention are well established. Emerging experimental and clinical data now suggest that combining GPIIb/IIIa inhibition with reduced-dose thrombolytic therapy may improve early IRA patency without increasing bleeding risk.

CONCLUSIONS

Given the strong clinical and physiologic rationale, clinical investigation in acute ST segment elevation MI is currently focused on combining the potent GPIIb/IIIa receptor inhibitors with reduced-dose fibrinolytic agents in acute MI, with the goal of overcoming "thrombolytic resistance."

Thrombolysis with saruplase versus streptokinase in acute myocardial infarction: five-year results of the PRIMI trial

BACKGROUND

Short-term safety and efficacy of thrombolysis with saruplase in acute myocardial infarction have been shown in several trials. To assess long-term outcome of patients treated with saruplase or streptokinase for myocardial infarction, a 5-year follow-up of patients included in the Pro-Urokinase in Myocardial Infarction Trial was performed.

METHODS AND RESULTS

Follow-up data are available from 8 centers on 255 (92.4%) of 276 included patients. The 5-year mortality rate was comparable with 20.8% of patients in the saruplase group and 16.9% in the streptokinase group (odds ratio 1.29, 95% confidence interval 0.69 to 2.42). In both groups, a considerable number of fatal cardiovascular events occurred more than 1 year after study inclusion. Rates of percutaneous transluminal coronary angioplasty and coronary artery bypass grafting were comparable in both groups. Reinfarction within 5 years occurred in 19.0% of patients in the saruplase group and tended to be less frequent at 10.8% after streptokinase treatment (odds ratio 1.94, 95% confidence interval 0.98 to 3.84). In both groups, the majority of reinfarctions took place more than 3 months after study inclusion. The 5-year stroke rate was 3.6% and 7.2% in the saruplase and streptokinase groups, respectively (odds ratio 0.49, 95% confidence interval 0.16 to 1.47). Subjective symptoms of heart failure and angina pectoris were comparable in both groups.

CONCLUSIONS

Our data are consistent with a similar long-term outcome for patients treated with saruplase or streptokinase. Despite the low-risk profile of the patient cohort, there were considerable adverse event rates over a 5-year period.

Angiographically documented late reocclusion after successful coronary angioplasty of an infarct-related lesion is a powerful predictor of long-term mortality

BACKGROUND

Late reocclusion of an infarct-related artery (IRA) that was patent in the early days after acute myocardial infarction (MI) is a frequent event; the reocclusion rate may be as high as 30%. Few studies have been designed to analyze the impact of late reocclusion of the IRA on late survival.

METHODS AND RESULTS

We studied 528 patients who all had a patent IRA after a successful PTCA procedure 10+/-6 days after MI and who underwent systematic 6-month angiographic follow-up to assess late patency of the IRA. We compared long-term survival of patients with and without late reocclusion. Based on the results of 6-month follow-up angiography, 2 groups of patients were defined: (1) 90 patients (17%) with reocclusion (Thrombolysis In Myocardial Infarction [TIMI] flow 0 or 1) and (2) 438 patients (83%) without reocclusion. Long-term clinical follow-up was obtained for all 528 patients at a median of 5.7 years after follow-up angiography (6.4 years after PTCA). The overall actuarial 8-year total mortality rate was 13%. At the end of follow-up, there were 35 deaths (8%) among the 438 patients without reocclusion and 18 deaths (20%) among the 90 patients with reocclusion (P=0.002). The actuarial 8-year total mortality rate was 10% in patients without reocclusion and 28% in patients with reocclusion (P=0.0003). The actuarial cardiovascular mortality rate was 7% in patients without reocclusion and 25% in patients with reocclusion (P<0.0001). The impact of reocclusion on long-term mortality was greater in patients with anterior MI.

CONCLUSIONS

Late IRA patency is strongly associated with long-term survival after MI. These observations should encourage prospective studies to evaluate the impact of strategies designed to prevent late reocclusion in postinfarction patients.

Long-term arterial patency after coronary reperfusion

Coronary reocclusion is a frequent event after reperfusion and may be responsible for the deterioration of left ventricular function. It may occur early as well as in the chronic phase after hospital discharge. Current, evidence based, strategies to prevent reocclusion include antiplatelet and anticoagulant agents as well as the use of intracoronary stenting in those patients who are treated by PTCA. The combination of aspirin and ticlopidine adds on the results of stenting. Further treatments are currently investigated and may significantly improve the long-term coronary patency.

[The prognostic factors after an acute myocardial infarct treated with fibrinolytics]

BACKGROUND

The usefulness of the exercise test in evaluating patients with an acute myocardial infarction treated with fibrinolytics is controversial. On the other hand, the prognostic value of a patent infarct-related artery has not been clearly established. The objectives of this study were to assess the validity of the exercise test and to study the prognostic value of the artery patency after a myocardial infarction.

MATERIAL AND METHODS

We studied 99 patients with a myocardial infarction treated with fibrinolytics, non-complicated. An exercise test and a cardiac catheterization were performed in the first month. The patients were followed-up for 2 years, recording the major cardiac events (death and reinfarction) and the minor events (angina class (II, left cardiac failure class (II or maintained ventricular tachycardia).

RESULTS

On multivariate analysis with Cox regression, a workload < 4 METS at the exercise test was the only independent prognostic factor of major events (RR 5.6; CI 95% 1.68-19). The independent prognostic factors of minor events were: multivessel disease (RR 3.36; CI 95% 1.56-7.24), anterior infarction (RR 3.15; CI 95% 1.3-7.6), abnormal exercise test (RR 2.98; CI 95% 1.46-6.09) and ejection fraction < or = 40% (RR 2.48; CI 95% 1.07-5.74). The patency of the infarct-related artery was not a predictor of events.

CONCLUSIONS

The exercise test is useful in predicting the prognosis in patients treated with fibrinolytics. An occluded infarct-related artery was not an independent predictor of cardiac events in 2 years of follow-up.

The beneficial effect of a beta-D-xyloside, Iliparcil, in the prevention of postthrombolytic rethrombosis in the rat

The effect of Iliparcil, a new orally active beta-D-xyloside venous antithrombotic, was studied on the rethrombosis following thrombolytic therapy in rats, using a modified Umetsu model. The drug was administered by oral route prior to thrombolytic therapy, which consisted of administering a combination of heparin and urokinase (H/U) at 37.5 and 70,000 IU/kg, respectively. Time to reocclusion increased from 3.9 min with saline to 10.5 min following H/U injection. When Iliparcil (30 mg/kg, oral route) was administered 4 h before H/U injection, the time to reocclusion was increased by 250% compared with H/U alone (p < 0.001). Similarly, dermatan sulfate (DS), administered intravenously (3 mg/kg) 5 min before thrombus induction, also increased the time to reocclusion (300% compared with H/U alone; p < 0.001). It was also shown that times to reocclusion following Iliparcil or DS treatments were still increased even when heparin dosage was decreased. These results suggest that an antithrombotic product derived from the beta-D-xyloside family could be advantageously used in combination with thrombolytic treatment instead of heparin, which causes complications and side effects.

Incidence and predictors of restenosis after successful primary coronary angioplasty for acute myocardial infarction: the importance of age and procedural result

BACKGROUND

Previous studies have suggested that restenosis and reocclusion occur frequently in patients with acute coronary syndromes. This study was undertaken to assess the incidence and predictors of restenosis in a cohort of patients who underwent successful primary coronary angioplasty for acute myocardial infarction.

METHODS

Three hundred twelve patients who underwent successful primary angioplasty of a native coronary vessel were candidates for follow-up coronary angiography. This was performed in 284 patients (92%) at the 3- or 6-month follow-up. Quantitative coronary angiography was performed with the CMS system. Multivariate analysis was performed to determine independent predictors of restenosis.

RESULTS

Restenosis, defined as a diameter stenosis of >50%, occurred in 27% of patients at 3 months and in 37% of patients at 6-month follow-up. Reocclusion occurred in 4% and 6%, respectively. Reference diameter (vessel size) was related to restenosis. Age and lumen diameter immediately after angioplasty were independent predictors of restenosis. Young patients (<50 years) and patients with a minimal luminal diameter of more than 2.5 mm had restenosis rates of <25%. The radionuclide ejection fraction was 46% in patients with restenosis compared with 47% in patients without restenosis.

CONCLUSIONS

The incidence of restenosis after successful primary coronary angioplasty for acute myocardial infarction is comparable to the reported incidence after elective coronary angioplasty for stable angina. Restenosis is related to age and the lumen diameter after angioplasty and does not affect left ventricular function in this population.

Intravenous diltiazem in acute myocardial infarction. Diltiazem as adjunctive therapy to activase (DATA) trial

OBJECTIVES

This study was defined as a pilot investigation of the usefulness and safety of intravenous diltiazem as adjunctive therapy to tissue plasminogen activator in acute myocardial infarction, followed by oral therapy for 4 weeks.

BACKGROUND

Experimental studies have documented that calcium antagonists protect the myocardial cell against the damage caused by coronary artery occlusion and reperfusion, yet no benefits have been conclusively demonstrated in acute myocardial infarction (AMI) in humans.

METHODS

In this pilot study, 59 patients with an AMI treated with tissue-type plasminogen activator (t-PA) were randomized, double blinded, to intravenous diltiazem or placebo for 48 h, followed by oral therapy for 4 weeks. The primary objective was to detect an effect on indices of regional left ventricular function and perfusion. Patients were also closely monitored for clinical events, coronary artery patency and indices of infarct size and of left ventricular function.

RESULTS

Creatine kinase elevation, Q wave score, global and regional left ventricular function and coronary artery patency at 48 h were not significantly different between the diltiazem and placebo groups. A greater improvement observed in regional perfusion and function with diltiazem was likely explained by initial larger defects. Diltiazem, compared to placebo, reduced the rate of death, reinfarction or recurrent ischemia at 35 days from 41% to 13% (p=0.027) and prevented the need for an urgent intervention. The rate of death or myocardial infarction was reduced by 65% (p=0.15). These benefits could not be explained by differences in baseline characteristics such as age, site and extent of infarction, time of inclusion or concomitant therapy. Heart rate and blood pressure were reduced throughout the study with active diltiazem treatment. Side effects of diltiazem were bradycardia and hypotension that required transient or permanent discontinuation of the study drug in 27% of patients, vs. 17% of patients with placebo.

CONCLUSIONS

A protective effect for clinical events related to early postinfarction ischemia and reinfarction was suggested in this study, with diltiazem administered intravenously with t-PA followed by oral therapy for 1 month, with no effect on coronary artery patency and left ventricular function and perfusion.

The significance of coronary arterial patency and ventricular function for prognosis after myocardial infarction

This paper assesses the evidence that early, complete and sustained recanalisation of the infarct related artery is the most important factor in limiting myocardial damage and improving outcome after coronary thrombosis. Besides the results of experimental studies, clinical support for the 'open artery' concept comes from, first, the consistent demonstration that patients with patent arteries survive better that those in whom patency is not achieved; second, from the observation that early treatment is associated with a better outcome, and third, from the demonstration that reperfusion by angioplasty or bypass grafting produces results as good or better than those of fibrinolytic therapy. Validation of adequate reperfusion as both the mechanism of, and a surrogate for, improved clinical outcome encourages 'perfusion endpoint' clinical trials to develop new reperfusion strategies.

Benefit of early sustained reperfusion in patients with prior myocardial infarction (the GUSTO-I trial). Global Utilization of Streptokinase and TPA for occluded arteries

The primary objective of this study was to characterize a large cohort of patients receiving thrombolytic therapy for acute myocardial infarction with respect to the group with a prior event. Patients were randomly assigned to 1 of 4 thrombolytic strategies. Baseline characteristics, 30-day outcomes, and 1-year mortality were compared between patients with (n = 6,704) and without (n = 34,143) prior myocardial infarction. Patients with prior myocardial infarction presented to the hospital earlier than those having their first event, but institution of thrombolytic therapy was delayed. Mortality at 30 days (11.7% vs 5.9%, p = 0.001) and 1 year (17.3% vs 8.2%, p < 0.001) was greater among patients with prior infarction, and independent of other demographic variables. Accelerated alteplase was more effective than streptokinase or combination therapy (30-day mortality 10.4% vs 12.2%, p = 0.012; 1-year mortality 15.9% vs 17.8%, p = 0.041). Infarct vessel patency did not differ between those with and without prior myocardial infarction (67.3% vs 67% at 90 minutes, p = 0.92); however, recurrent ischemia was more common in patients with prior myocardial infarction. Patients with healed myocardial infarction should be educated to ensure early hospital admission if they develop symptoms suggestive of acute infarction, and upon hospital arrival should be promptly triaged to receive reperfusion therapy with accelerated alteplase.

Coronary angioscopic findings in the infarct-related vessel within 1 month of acute myocardial infarction: natural history and the effect of thrombolysis

BACKGROUND

Limited angioscopic information is available on the natural history of infarct-related plaque after myocardial infarction (MI), in particular the effect of thrombolysis.

METHODS AND RESULTS

We studied with angioscopy the morphological characteristics of the infarct-related lesion in 56 patients between 24 hours and 4 weeks after MI. Forty of these patients were initially treated with a thrombolytic agent. Most lesions were complex (complex + ulcerated shape = 54%). The predominant color of the plaque was yellow in 79% of cases; only 6% were uniformly white. Angioscopically visible thrombus was found in 77% of cases. Despite angioscopic evidence of instability, only 7% of the patients had post-MI angina. During the 1-month time window since the occurrence of MI, there was no significant difference in the angioscopic appearance of the plaque except for a slight increase in uniformly white plaques (P=.07). The use of a thrombolytic agent at the onset of MI was associated with a reduction in thrombus size and less protruding thrombi (P=.02) but not with a decreased frequency of plaque containing thrombi. Furthermore, a trend for more frequently ulcerated plaques (45% versus 16%, P=.06) was associated with the use of a thrombolytic agent.

CONCLUSIONS

These results suggest that healing of the infarct-related lesion requires more than 1 month and that an "unstable" yellow plaque with adherent thrombus is common during that period. This finding may partly explain the unique behavior of recent infarct-related lesions, which are more prone to occlude than other lesions.

Long-term implications of reocclusion on left ventricular size and function after successful thrombolysis for first anterior myocardial infarction

BACKGROUND

Successful thrombolysis can prevent left ventricular dilatation after acute myocardial infarction. However, in almost 30% of patients, reocclusion occurs. The aim of this study was to assess the long-term implications of reocclusion on left ventricular size and function.

METHODS AND RESULTS

Fifty-six patients were studied with two-dimensional echocardiography at baseline (2 +/- 1.6 days) and 5.0 +/- 1.4 years after first anterior myocardial infarction. All patients (a subset of those enrolled in the APRICOT trial) had a patent infarct-related artery when studied < 48 hours after thrombolysis and underwent repeat coronary angiography at 3 months. Baseline characteristics were comparable in patients with (n = 17) and without reocclusion (n = 39). Left ventricular volume indexes were stable in patients without reocclusion. Patients with reocclusion, however, showed a significant increase in end-diastolic volume index (EDVI; P = .008) and end-systolic volume index (ESVI; P = .039). Furthermore, patients without reocclusion demonstrated improvement in wall motion score index (WMSI; P = .0001) and ejection fraction (EF; P = .016), whereas patients with reocclusion did not. After 5 years, patients with reocclusion had significantly larger volume indexes (EDVI, 99 +/- 41 versus 76 +/- 22 mL/m2, P = .007; ESVI, 59 +/- 40 versus 39 +/- 20 mL/m2, P = .017) and more compromised left ventricular function (WMSI, 1.63 +/- 0.33 versus 1.39 +/- 0.32, P = .013; EF, 45 +/- 13% versus 51 +/- 11%, P = .077) than patients without reocclusion. Multivariate analysis identified baseline WMSI and reocclusion as significant independent predictors of left ventricular dilatation.

CONCLUSIONS

Reocclusion of the infarct-related artery within 3 months of successful thrombolysis is associated with left ventricular dilatation and is detrimental to functional recovery of left ventricular function 5 years after first anterior myocardial infarction.

Influence of early prehospital thrombolysis on mortality and event-free survival (the Myocardial Infarction Triage and Intervention [MITI] Randomized Trial). MITI Project Investigators

The Myocardial Infarction Triage and Intervention Trial of prehospital versus hospital administration of thrombolytic therapy markedly reduced hospital treatment times, but the 2 groups had similar outcomes. However, patients treated < 70 minutes from symptom onset had better short-term outcomes. The purpose of this study was to determine the long-term influence of very early thrombolytic treatment for acute myocardial infarction. A total of 360 patients were followed for vital status and cardiac-related hospital admissions over a period of 34 +/- 16 months. Patients enrolled in the trial had symptoms for < or = 6 hours, ST-segment elevation on the prehospital electrocardiogram, and no risk factors for serious bleeding. They received aspirin and recombinant tissue plasminogen activator either before or after hospital arrival. Primary end points in this study included long-term survival and survival free of death or readmission to the hospital for angina, myocardial infarction, congestive heart failure, or revascularization. Two-year survival was 89% for prehospital- and 91% for hospital-treated patients (p = 0.46). Event-free survival at 2 years was 56% and 64% for prehospital- and hospital-treated patients, respectively (p = 0.42). In patients treated < 70 minutes from symptom onset, 2-year survival was 98%, and it was 88% for those treated later (p = 0.12). Two-year event-free survival was 65% for patients treated early and 59% for patients treated later (p = 0.80). In this trial, poorer long-term survival was associated with advanced age, history of congestive heart failure, and coronary artery bypass surgery performed before the index hospitalization, but not with time to treatment.