Reperfusion Strategy and Infarct Size in ST-Elevation Myocardial Infarction (STEMI)

Background

Thrombolysis remains an important reperfusion strategy for ST segment elevation myocardial infarction (STEMI) in many outer metropolitan and regional settings. We looked to compare myocardial infarct size (assessed by peak high sensitivity troponin) according to reperfusion strategy in STEMI.

Methods

We performed a cohort study of consecutive STEMI patients presenting to two outer-metropolitan hospitals. Peak troponin during index hospitalisation was collected over a six-year period (2014-2019) along with blinded assessment for major adverse cardiac events (MACE) at one month follow-up (a composite of all-cause mortality, myocardial infarction, unplanned revascularization and readmission for heart failure).

Results

A total of 633 patients were included with 447 (71% undergoing thrombolysis) and the remainder undergoing primary percutaneous intervention (pPCI). Despite similar ischaemic times, myocardial necrosis was numerically greater in thrombolysed patients (median troponin =26,945ng/L IQR 78,766ng/L) v median 12,627ng/L IQR 43,646 ng/L in pPCI group) however this did not reach statistical significance. For the primary outcome (MACE) thrombolysis was associated with no higher incidence of adverse events (12% v 10%, OR: 1.27, p=0.52).

Conclusions

There was a higher median troponin after thrombolysis compared to pPCI suggesting a greater degree of myocardial injury, however this did not reach statistical significance. Furthermore we did not demonstrate a statistical difference in the primary MACE endpoint. Our study is hypothesis generating and further local prospective randomized comparisons are required.