The Thrombolysis in Myocardial Infarction (TIMI) trials: the first decade

Transition Towards Transradial Approach Improves Outcomes of Acute Myocardial Infarction PCI

INTRODUCTION AND AIM

Transradial (TRA) instead of transfemoral (TFA) approach strategy has been presented in research literature as superior access strategy especially for acute ST elevation myocardial infarction (STEMI) primary percutaneous coronary intervention (PCI). There is a paucity of registry-based data of outcomes from default TRA strategy compared to TFA.

MATERIALS AND METHODS

All-comers STEMI PCI institutional Registry identified 1808 consecutive patients in time-frame of 40 months from 2007 to 2010, without making any exclusions. Moreover, we applied Propensity Score Matching (PSM) to replace randomization, address the potential confounding and selection bias. PSM derived 565 congruent pairs of patients from the groups.

RESULTS

After 30 days the primary composite endpoint of major adverse cardiovascular events (MACE) was in favor of TRA 6.5% vs. 12.4% in TFA group, simultaneously secondary endpoints of death in TRA with rate of 4.8% and with rate of 10.1% in TFA. Moreover, the rate of major access related bleeding was 1.1% in TRA vs. 8.5% in TFA, in contrast the major non-access related bleeding was 1.8% and 2.4% respectively showed no significant difference. One year Kaplan Meier survival plots were in favor of TRA.

CONCLUSIONS

Default transradial access strategy is associated with improved STEMI PCI outcomes.

Revascularization grading in endovascular acute ischemic stroke therapy

BACKGROUND

Recanalization and angiographic reperfusion are key elements to successful endovascular and interventional acute ischemic stroke (AIS) therapy. Intravenous recombinant tissue plasminogen activator (rt-PA), the only established revascularization therapy approved by the US Food & Drug Administration for AIS, may be less effective for large artery occlusion. Thus, there is enthusiasm for endovascular revascularization therapies, which likely provide higher recanalization rates, and trials are ongoing to determine clinical efficacy and compare various methods. It is anticipated that clinical efficacy will be well correlated with revascularization of viable tissue in a timely manner.

METHOD

Reporting, interpretation, and comparison of the various revascularization grading methods require agreement on measurement criteria, reproducibility, ease of use, and correlation with clinical outcome. These parameters were reviewed by performing a Medline literature search from 1965 to 2011. This review critically evaluates current revascularization grading systems.

RESULTS AND CONCLUSION

The most commonly used revascularization grading methods in AIS interventional therapy trials are the thrombolysis in cerebral ischemia (TICI, pronounced "tissy") and thrombolysis in myocardial ischemia (TIMI) scores. Until further technical and imaging advances can incorporate real-time reliable perfusion studies in the angio-suite to delineate regional perfusion more accurately, the TICI grading system is the best defined and most widely used scheme. Other grading systems may be used for research and correlation purposes. A new scale that combines primary site occlusion, lesion location, and perfusion should be explored in the future.

Paramedics and pre-hospital management of acute myocardial infarction: diagnosis and reperfusion

In this paper, we discuss and critically analyse pre-hospital management of acute myocardial infarction (AMI). It is clear from several large studies that rapid diagnosis and application of thrombolysis reduces morbidity and mortality rates. Strategies that improve time to treatment in the pre-hospital setting are therefore of fundamental importance in the management of this fatal disease. The advantage of 12 lead electrocardiography use by paramedics to diagnose AMI and reduce time to treatment is discussed. Moreover, paramedic application of thrombolysis in the pre-hospital environment is examined. Several studies conducted worldwide support the notion that ambulance services can play a role in minimising time to treatment for patients with AMI. The contribution of early intervention by paramedics trained in critical care is potentially considerable, particularly in the important chain of survival that is often initiated by pre-hospital intervention.

Rapid early action for coronary treatment: rationale, design, and baseline characteristics. REACT Research Group

OBJECTIVE

Early reperfusion for acute myocardial infarction (AMI) can reduce morbidity and mortality, yet there is often delay in accessing medical care after symptom onset. This report describes the design and baseline characteristics of the Rapid Early Action for Coronary Treatment (REACT) community trial, which is testing community intervention to reduce delay.

METHODS

Twenty U.S. communities were pair-matched and randomly assigned within pairs to intervention or comparison. Four months of baseline data collection was followed by an 18-month intervention of community organization and public, patient, and health professional education. Primary cases were community residents seen in the ED with chest pain, admitted with suspected acute cardiac ischemia, and discharged with a diagnosis related to coronary heart disease. The primary outcome was delay time from symptom onset to ED arrival. Secondary outcomes included delay time in patients with MI/unstable angina, hospital case-fatality rate and length of stay, receipt of reperfusion, and ED/emergency medical services utilization. Impact on public and patient knowledge, attitudes, and intentions was measured by telephone interviews. Characteristics of communities and cases and comparability of paired communities at baseline were assessed.

RESULTS

Baseline cases are 46% female, 14% minorities, and 73% aged > or =55 years, and paired communities have similar demographics characteristics. Median delay time (available for 72% of cases) is 2.3 hours and does not vary between treatment conditions (p > 0.86).

CONCLUSIONS

REACT communities approximate the demographic distribution of the United States and there is baseline comparability between the intervention and comparison groups. The REACT trial will provide valuable information for community educational programs to reduce patient delay for AMI symptoms.

TNK-tissue plasminogen activator in acute myocardial infarction. Results of the Thrombolysis in Myocardial Infarction (TIMI) 10A dose-ranging trial

BACKGROUND

TNK-tissue plasminogen activator (TNK-TPA) is a genetically engineered variant of TPA, which in experimental models has a slower plasma clearance and greater fibrin specificity and is 80-fold more resistant to plasminogen activator inhibitor-1 than alteplase TPA.

METHODS AND RESULTS

The thrombolysis in Myocardial Infarction (TIMI) 10A trial was a Phase 1, dose-ranging pilot trial designed to evaluate the pharmacokinetics, safety, and efficacy of TNK-TPA in patients with acute myocardial infarction. One hundred thirteen patients with acute ST-segment elevation myocardial infarction presenting within 12 hours and without contraindications to thrombolysis were enrolled and treated with a single bolus of TNK-TPA over 5 to 10 seconds with doses ranging from 5 to 50 mg. TNK-TPA demonstrated a plasma clearance of 151 +/- 55 mL/min and a half-life of 17 +/- 7 minutes. Comparable values for wild-type TPA are 572 +/- 132 mL/min and 3.5 +/- 1.4 minutes, respectively. Systemic fibrinogen and plasminogen levels fell by only 3% and 13%, respectively, at 1 hour after TNK-TPA administration. TIMI grade 3 flow at 90 minutes was achieved in 57% to 64% of patients at the 30- to 50-mg doses. Seven patients (6.2%) experienced a major hemorrhage, which occurred at a vascular access site in six patients.

CONCLUSIONS

TNK-TPA has a prolonged half-life so it can be administered as a single bolus. TNK-TPA appears to be very fibrin specific, and the initial patency and safety profiles are encouraging. Further study of this new thrombolytic agent is ongoing.