Implications of ischaemic area at risk and mode of reperfusion in ST-elevation myocardial infarction.

OBJECTIVE: Uncertainty exists concerning the relative merits of pharmacological versus mechanical coronary reperfusion in patients presenting early with ST-elevation myocardial infarction (STEMI) with extensive myocardium at risk. Accordingly, we investigated whether the extent of baseline ST-segment shift was related to the response of either reperfusion modality in patients with STEMI presenting within 3 h of symptoms.

METHODS: We analysed baseline ECGs from 1859 patients enrolled in the STrategic Reperfusion Early After Myocardial Infarction (STREAM) trial. The sum of ST-segment elevation (∑STE) and ST-segment deviation (∑STD) was categorised into quartiles and associations with the primary endpoint (30-day death/shock/congestive heart failure/re-myocardial infarction) for each reperfusion strategy (early fibrinolysis vs primary percutaneous coronary intervention) were explored.

RESULTS: Overall, there was a progressive rise in the 30-day primary endpoint according to quartiles of baseline ∑STE (10.3% (0-5 mm), 12.4% (5.5-8.5 mm), 12.1% (9-13.5 mm), 17.6% (> 14.0 mm), p = 0.008) and ∑STD (9.0% (0-9 mm), 13.5% (9.5-14 mm), 14.7% (14.5-20 mm), 15.3% (> 20 mm), p = 0.019). Both ∑STE and ∑STD were associated with the primary endpoint (∑STE: p = 0.071; ∑STD: p = 0.024). However, there was no interaction between quartiles of baseline ∑STE or ∑STD and efficacy of either reperfusion strategy on the 30-day clinical outcomes (∑STE: p (interaction) = 0.696; ∑STD: p (interaction) = 0.542).

CONCLUSIONS: These data demonstrate an association between ∑STE or ∑STD on the baseline ECG and clinical events at 30 days following reperfusion therapy in STEMI. More importantly, the response to different reperfusion strategies was not influenced by the extent of jeopardised myocardium.

TRIAL REGISTRATION NUMBER: NCT00623623; Post-results.