The impact of pre-hospital thrombolytic treatment on re-infarction rates: analysis of the Myocardial Infarction National Audit Project (MINAP)

Abstract

Objective To examine the frequency and determinants of re-infarction after thrombolytic treatment of STelevation myocardial infarction (STEMI). Design Observational study of national registry. Setting Emergency ambulance services and admitting hospitals in England and Wales. Patients 35356 cases of STEMI given thrombolytic treatment in 2005-6. Main outcome measures Re-infarction during hospital admission Results For 22391 (63.3%) the presence or absence of re-infarction was recorded, and 1460 (6.5%) had re-infarction. Re-infarction rates with in-hospital treatment were similar for reteplase (6.5%) and tenecteplase (6.4%). When the interval from pre-hospital treatment to hospital arrival was greater than 30 minutes re-infarction rates were 12.5% for reteplase, and 11.4% for tenecteplase. Overall, re-infarction rates were higher after pre-hospital treatment with tenecteplase than reteplase (9.6% vs. 6.6%, p = 0.005). After multivariate analysis independent predictors of re-infarction for tenecteplase were pre-hospital treatment, OR 1.44 (95% CI 1.21 to 1.71, p < 0.001) and weight in the highest quartile compared to the lowest, OR 1.66 (95% CI 1.19 to 2.31, p = 0.003). For reteplase neither factor predicted reinfarction. Bleeding was less common with pre-hospital treatment -overall 1.8% against 3.1%; intra-cerebral bleeding 0.4% against 0.7%. Conclusion Pre-hospital treatment with tenecteplase was associated with higher re-infarction rates. Longer intervals from pre-hospital treatment to arrival in hospital were associated with high re-infarction rates for both tenecteplase and reteplase. Differences in the use of adjunctive anti-thrombotic therapy in the two treatment environments may underlie the differences in re-infarction rates and bleeding complications observed between pre-hospital and in-hospital thrombolytic treatment. [250]

Predictors of in-hospital mortality for patients admitted with ST-elevation myocardial infarction: a real-world study using the Myocardial Infarction National Audit Project (MINAP) database

“…Administration of thrombolysis out of hospital was associated with a threefold better outcome than that of in-hospital thrombolysis and corroborate recent findings that longer intervals from prehospital treatment to arrival in hospital are associated with high re-infarction rates, which in turn are associated with elevated mortality rates 6. Although the mortality risk reduction associated with prehospital thrombolysis is likely to reflect the reduction in delay to thrombolysis it is also possible that those who received thrombolysis out of hospital were a different subpopulation from those who had treatment in hospital.…”

“…Although primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) offers advantages over and above thrombolysis for STEMI,2 – 4 the majority of patients who have STEMI in the United Kingdom are treated with thrombolytic agents 5. Implicit to thrombolysis therapy is the requirement for its prompt delivery as this has been demonstrated to influence outcome 6 – 10…”

Almanac 2011: acute coronary syndromes. The national society journals present selected research that has driven recent advances in clinical cardiology

“…This may be justified if fibrinolysis can be delivered within 30 min after presentation when primary PCI is not immediately available, because treatment delays by either modality are associated with substantial increases in mortality 36. This has provided justification for programmes of pre-hospital thrombolysis, particularly in rural regions where transport times are prolonged, but enthusiasm for this approach may now be diminished by evidence from the MINAP registry showing higher rates of reinfarction compared with in-hospital thrombolytic treatment for patients with STEMI 68. The difference in reinfarction rates was only significant for tenecteplase (9.6% vs 6.4%), not reteplase, and was particularly marked when transport times exceeded 30 min.…”

The impact of prehospital thrombolytic treatment on re-infarction rates

“…To the editor: We congratulate Horne and colleagues1 for their paper drawing attention to the high risk of re-infarction for patients receiving prehospital thrombolytic therapy for ST-segment elevation myocardial infarction. We disagree with their main conclusion that the major cause of this is underdosing with heparin and delay in commencing a heparin infusion.…”