Abstract
AIMS: We examined the association between the symptom-to-reperfusion-time and cardiovascular magnetic resonance (CMR)-derived global strain parameters and transmural infarct extent in ST-segment elevation myocardial infarction (STEMI) patients.
METHODS AND RESULTS: The study included 108 STEMI patients who underwent successful primary percutaneous coronary intervention (PPCI). Patients were categorized according to the median symptom-to-reperfusion-time: shorter (<160 min, n = 54) and longer times (>160 min, n = 54). CMR was performed 2-7 days after PPCI and at 1-month. CMR cine imaging was performed for functional assessment and late gadolinium enhancement to evaluate transmural infarct extent. Myocardial feature-tracking was used for strain analysis. Groups were comparable in relation to incidence of LAD disease and pre and post-PPCI TIMI flow grades. The mean transmural extent score at follow-up was lower in patients with shorter reperfusion time (p < 0.01). Both baseline and follow-up maximum transmural extent scores were smaller in patients with shorter reperfusion time (p = 0.03 for both). Patients with shorter reperfusion time had more favorable global left ventricular (LV) circumferential strain (baseline, p = 0.049; follow-up, p = 0.01) and radial strain (baseline, p = 0.047; follow-up, p < 0.01), while LV longitudinal strain appeared comparable for both baseline and follow-up (p > 0.05 for both). In multivariable regression analysis including all 3 strain directions, baseline LV circumferential strain was independently associated with the mean transmural extent score at follow-up (β=1.89, p < 0.001).
CONCLUSION: In STEMI patients, time-to-reperfusion was significantly associated with smaller transmural extent of infarction and better LV circumferential and radial strain. Moreover, infarct transmurality and residual LV circumferential strain are closely linked.