Mean platelet volume is a predictor of ST resolution following thrombolysis in acute ST elevation myocardial infarction.

Background: Larger mean platelets volumes (MPV) are thrombogenic and frequently seen after ST-segment elevation myocardial infarction (STEMI). This study aimed to examine the association of MPV and resolution of ST-segment after thrombolysis in STEMI patients as and its impact on clinical outcome.

Methods: Patients presenting to the emergency department with the diagnosis of first STEMI and were referred to thrombolysis were screened. Patients with ≥50% ST-segment resolution (STR) 90minutes after thrombolysis were assigned as "Responder" and those with <50% STR were assigned as "Non-Responders". Demographic, clinical comorbidities and risk factor were recorded along with and angiographic data. In-hospital occurrence of major adverse cardiac events (MACE), including acute heart failure (AHF), reinfarction and death were investigated. Additionally, the patients were followed for 6 additional months after their discharge from the hospital.

Results: STR≥50% was seen in 60.2% of patients after thrombolysis. Responders had significantly lower MPV (P=0.001) and the critical MPV values were 8.0 femtoliter (fL) and 8.2fL in predicting STR and MACE. Patients with MPV ≥8.2fL had lower probability of STR and higher rates of AHF (P<0.001), and MACE (P=0.001) compared to the patients with lower platelet volume. In multivariate regression, MPV was an independent predictor of STR (P<0.001) as well as MACE (HR=4.8, 95% CI of 1.8-12.4; P=0.001). Triple vessel disease was another independent factor that predicted MACE.

Conclusion: Higher MPV's at admission were associated with lower STR and higher occurrence of major adverse cardiac events in patients receiving thrombolytic therapy for first time STEMI.