Recurrent ischemia after thrombolysis for acute myocardial infarction

Rationale and design of the OPTIMAL-REPERFUSION trial: A prospective randomized multi-center clinical trial comparing different fibrinolysis-transfer percutaneous coronary intervention strategies in acute ST-segment elevation myocardial infarction

Primary percutaneous coronary intervention (PPCI), the preferred reperfusion strategy for all acute ST‐segment elevation myocardial infarction (STEMI) patients, is not universally available in clinical practice. Pharmacoinvasive strategy has been proposed as a therapeutic option in patients with STEMI when timely PPCI is not feasible. However, pharmacoinvasive strategy has potential delay between clinical patency and complete myocardial perfusion. The optimal reperfusion strategy for STEMI patients with anticipated PPCI delay according to current practice is uncertain. OPTIMAL‐REPERFUSION is an investigator‐initiated, prospective, multicenter, randomized, open‐label, superiority trial with blinded evaluation of outcomes. A total of 632 STEMI patients presenting within 6 hours after symptom onset and with an expected time of first medical contact to percutaneous coronary intervention (PCI) ≥120 minute will be randomized to a reduced‐dose facilitated PCI strategy (reduced‐dose fibrinolysis combined with simultaneous transfer for immediate invasive therapy with a time interval between fibrinolysis to PCI < 3 hours) or to standard pharmacoinvasive treatment. The primary endpoint is the composite of death, reinfarction, refractory ischemia, congestive heart failure, or cardiogenic shock at 30‐days. Enrollment of the first patient is planned in March 2021. The recruitment is anticipated to last for 12 to 18 months and to complete in September 2023 with 1 year follow‐up. The OPTIMAL‐REPERFUSION trial will help determine whether reduced‐dose facilitated PCI strategy improves clinical outcomes in patients with STEMI and anticipated PPCI delay. This study is registered with the ClinicalTrials.gov (NCT04752345).

Admission hyperglycemia is associated with failed reperfusion following fibrinolytic therapy in patients with STEMI: results of a retrospective study

BACKGROUND

Hyperglycemia on admission is associated with increased mortality rates in patients with ST-elevation myocardial infarction (STEMI) who are treated with either fibrinolytic therapy (FT) or primary percutaneous coronary intervention (PCI). However, data regarding the relationship between hyperglycemia and the success of FT are lacking. The aim of this study was to investigate the value of admission blood glucose for the prediction of failed reperfusion following FT.

METHODS AND RESULTS

This is a retrospective study of 304 STEMI patients who received FT and whose admission glucose levels were recorded. The main outcome measure was ST segment resolution≥50%. The median (interquartile range [IQR]) blood glucose level in the entire study group was 112 (95-153). In 92 (30.2%) patients, FT was unsuccessful and rescue PCI was performed. Admission glucose (126 [99-192] vs. 110 [94-144] mg/dL, p<0.001), time from symptom onset to FT (180 [120-270] vs. 150 [120-180] min, p=0.009), and maximum ST elevation amplitude (3 [2-7] vs. 3 [2-6] mm, p=0.05) were higher in the failed reperfusion group than in the reperfusion group. Admission hyperglycemia was an independent predictive factor for failed reperfusion (hazard ratio 4.79 [1.80-12.76], p=0.002), along with time from symptom onset to fibrinolysis and anterior wall myocardial infarction.

CONCLUSIONS

In patients with STEMI who undergo FT, admission hyperglycemia is an independent predictor of the failure of fibrinolysis.

Long-Term Follow-Up of Early Versus Delayed Invasive Approach After Fibrinolysis in Acute Myocardial Infarction

Background—

Optimal reperfusion strategy in ST-elevation myocardial infarction is controversial. Failure of fibrinolytic therapy is related to limited efficacy, high reocclusion rates, reinfarction, and systemic bleeding complications. Data on the impact of percutaneous coronary intervention (PCI) after fibrinolysis are conflicting. The Southwest German Interventional Study in Acute Myocardial Infarction (SIAM III) evaluated the effects of transfer for early PCI in acute ST-elevation–myocardial infarction compared with a delayed PCI strategy.

Methods and Results—

SIAM III was a multicenter, randomized, prospective, controlled trial in patients with ST-elevation–myocardial infarction receiving fibrinolysis <12 hours after onset of symptoms. All patients received reteplase, aspirin in combination with ticlopidine, and heparin. Patients of the early PCI group were transferred within 6 hours after fibrinolysis for PCI. The delayed PCI group received elective PCI 2 weeks after fibrinolysis. In total, 197 patients were included; 163 were treated by PCI. The primary end point was the composite of death, reinfarction, target lesion revascularization, and ischemic events. During a mean follow-up time of 7.9±3.4 years (maximum, 11.2 years), early PCI was associated with a significant reduction of the primary end point (hazard ratio, 0.61 [95% confidence interval, 0.42 to 0.88]; P =0.008). Long-term survival was higher in the early PCI group ( P =0.057). Ischemic events were significantly reduced after early PCI ( P =0.003).

Conclusions—

Early PCI after fibrinolysis improves long-term event-free survival compared with a delayed PCI treatment strategy.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01124890.

ST-segment resolution 60 minutes after combination treatment of abciximab with reteplase or reteplase alone for acute myocardial infarction (30-day mortality results from the resolution of ST-segment after reperfusion therapy substudy)

The combination of abciximab with thrombolytic therapy when treating acute ST-elevation myocardial infarction has been hypothesized to enhance microvascular perfusion. Resolution of ST-segment elevation after thrombolytic therapy is believed to be a marker of myocardial reperfusion and to predict mortality rate. Among 16,588 patients enrolled in the Fifth Global Use of Strategies to Open Occluded Arteries in Acute Myocardial Infarction trial, 1,764 consecutive patients from selected centers had their study electrocardiograms evaluated by a core laboratory for ST-segment deviation resolution 60 minutes after treatment. Patients were categorized into 4 groups: complete resolution (>70%), partial resolution (<70% to 30%), no resolution (<30%), and worsening ST-segment deviation. Patients treated with reteplase or a combination of reteplase plus abciximab had similar rates of complete resolution (32% vs 34%), partial resolution (29% vs 27%), no resolution (15% vs 16%), and worsening ST-segment elevation (23 vs 23%; p = 0.59). The 30-day mortality rates in these 4 groups were 2.1%, 5.2%, 5.5%, and 8.1% (p <0.001). Even after accounting for baseline variables, incomplete ST-segment resolution (<70%) was associated with an increased risk of death within 30 days (adjusted hazard ratio 2.41, 95% confidence interval 1.25 to 4.63, p <0.008). Thus, ST-segment resolution at 60 minutes was no different in patients treated with full-dose reteplase from those treated with a combination of abciximab and reteplase. Patients with >70% ST-segment resolution within 60 minutes had markedly decreased mortality rates, irrespective of treatment.

Beneficial effects of immediate stenting after thrombolysis in acute myocardial infarction

OBJECTIVES

The Southwest German Interventional Study in Acute Myocardial Infarction (SIAM III) investigated potentially beneficial effects of immediate stenting after thrombolysis as opposed to a more conservative treatment regimen.

BACKGROUND

Treatment of acute myocardial infarction (AMI) by thrombolysis is compromised by Thrombolysis In Myocardial Infarction (TIMI) 3 flow rates of only 60% and high re-occlusion rates of the infarct-related artery (IRA). Older studies showed no benefit of coronary angioplasty after thrombolysis compared with thrombolytic therapy alone. This observation has been challenged by the superiority of primary stenting over balloon angioplasty in AMI.

METHODS

The SIAM III study was a multicenter, randomized, prospective, controlled trial in patients receiving thrombolysis in AMI (<12 h). Patients of group I were transferred within 6 h after thrombolysis for coronary angiography, including stenting of the IRA. Group II received elective coronary angiography two weeks after thrombolysis with stenting of the IRA.

RESULTS

A total of 197 patients were randomized, 163 patients fulfilled the secondary (angiographic) inclusion criteria (82 in group I, 81 in group II). Immediate stenting was associated with a significant reduction of the combined end point after six months (ischemic events, death, reinfarction, target lesion revascularization 25.6% vs. 50.6%, p = 0.001).

CONCLUSIONS

Immediate stenting after thrombolysis leads to a significant reduction of cardiac events compared with a more conservative approach including delayed stenting after two weeks.

Effects of different thrombolytic treatment regimen with abciximab and tirofiban on platelet aggregation and platelet-leukocyte interactions: a subgroup analysis from the GUSTO V and FASTER trials

BACKGROUND

Due to considerably high rates of reocclusion under standard thrombolytic therapy GP IIb/IIIa inhibitors have been combined with thrombolytics to improve therapeutic outcomes. Potential reasons for arterial reocclusion may be increased platelet activation, interaction of platelets with other cell types such as leukocytes and inadequate drug dosing due to lack of ideal platelet monitoring. We compared combination therapy regimens consisting of GP IIb/IIIa inhibitors and thrombolytics with respect to platelet inhibition and platelet-leukocyte interactions.

METHODS AND RESULTS

From the GUSTO V trial (standard rPA vs. reduced dose rPA and abciximab) and the FASTER trial (standard TNK-tPA vs. reduced dose TNK-tPA and tirofiban) 15 patients were monitored by platelet aggregometry, rapid platelet function assay (RPFA) and flow cytometry (FC). rPA alone (n = 5) caused initial increases in platelet aggregation. However, platelet aggregation was significantly (p < 0.05) and sufficiently (>80%) inhibited by abciximab/rPA (n = 5) and tirofiban/TNK-tPA (n = 5). The platelet inhibitory effect of tirofiban/TNK-tPA was more pronounced compared to abciximab/rPA with a significant difference after 2 h (p < 0.05). Tirofiban/TNK-tPA and abciximab/rPA caused decreases in platelet-leukocyte aggregates as well as in binding of specific antibodies to the platelet vitronectin receptor and P-selectin (p < 0.05, respect.). No differences among the treatment groups were seen with respect to antibody binding to MAC-1 and CD154/CD40 ligand.

CONCLUSIONS

Taken together, GP IIb/IIIa inhibitors overcome the platelet activating effect of thrombolytics resulting in sufficient platelet inhibition. RPFA is a suitable monitoring tool to accurately assess platelet inhibition. Within the given combination treatment regimen tirofiban appears to be more effective compared to abciximab and to exert effects beyond the inhibition of GP IIb/IIIa.

Reperfusion therapy for acute myocardial infarction with fibrinolytic therapy or combination reduced fibrinolytic therapy and platelet glycoprotein IIb/IIIa inhibition: the GUSTO V randomised trial

BACKGROUND

Plasminogen activator therapy for acute myocardial infarction is limited by lack of achievement of early, complete, and sustained reperfusion in a substantial proportion of patients. Many phase II trials have supported the potential of combined fibrinolytic therapy and platelet glycoprotein IIb/IIIa inhibition for improving reperfusion. We did a randomised, open-label trial to compare the effect of reteplase alone with reteplase plus abciximab in patients with acute myocardial infarction.

METHODS

16588 patients in the first 6 h of evolving ST-segment elevation myocardial infarction were randomly assigned standard-dose reteplase (n=8260) or half-dose reteplase and full-dose abciximab (n=8328). The primary endpoint was 30-day mortality, and secondary endpoints included various complications of myocardial infarction. Analysis was by intention to treat.

FINDINGS

At 30 days, 488 (5.9%) of patients in the reteplase group had died, compared with 468 (5.6%) in the combined reteplase and abciximab group (odds ratio 0.95 [95% CI 0.83-1.08], p=0.43). There were fewer deaths or non-fatal reinfarctions with the combination than with reteplase alone, and there was less need for urgent revascularisation and fewer major non-fatal ischaemic complications of acute myocardial infarction. On the other hand, there were more non-intracranial bleeding complications in the combination group. The rates of intracranial haemorrhage and non-fatal disabling stroke were similar.

INTERPRETATION

Although combined reteplase and abciximab was not superior to standard reteplase, the 0.3% absolute (5% relative) decrease in 30-day mortality fulfilled the criteria of non-inferiority. Combination therapy led to a consistent reduction in key secondary complications of myocardial infarction including reinfarction, which was partly counterbalanced by increased non-intracranial bleeding complications.