The impact of age on effects of pre-hospital initiation of high bolus dose of tirofiban before primary angioplasty for ST-elevation myocardial infarction

Abstract

Purpose: Glycoprotein IIb/IIIa inhibitors are favourable in ST-elevation myocardial infarction (STEMI) patients, and the additional value of early pre-hospital high bolus dose tirofiban has recently been established. The aim of this study was to determine the impact of age on myocardial reperfusion and clinical outcomes of pre-hospital administration of high bolus dose tirofiban.

Methods: This is a pre-specified sub-analysis of the multicentre, double-blind, placebo-controlled, randomised On-TIME 2 trial and it's open label phase. The primary endpoint was mean residual ST segment deviation 1 h after primary PCI and was evaluated in three age groups.

Results: Of the 466 patients in the highest tertile (≥68 years), median age was 74.4 years (IQR 71.3-78.6 years) and 231 (50%) were randomised to tirofiban. Mean residual ST segment deviation 1 h after PCI was significantly lower in elderly patients pre-treated with tirofiban compared to elderly patients without tirofiban pre-treatment (4.2 ± 5.2 mm vs 6.4 ± 7.5 mm, p = 0.001). Furthermore, elderly patients pre-treated with tirofiban had a non-significantly higher rate of 30-day major or minor bleeding compared to elderly patients without tirofiban pre-treatment (14.2% vs 9.0%, p = 0.088). 30-day net adverse clinical events in elderly patients with- or without tirofiban was not significantly different (11.9% vs 15.2%, p = 0.300).

Conclusion: The effect of pre-hospital initiation of high bolus dose tirofiban on myocardial reperfusion, as determined by ST-segment resolution is highest in the elderly patients. However, this was associated with a trend towards more bleeding complications, resulting in a balanced clinical effect after 30-day follow-up. Future studies should evaluate whether the elderly STEMI patient may benefit from highly effective and safer antiplatelet therapy.