Low-dose alteplase during PCI increases microvascular obstruction in STEMI patients
Adjunctive treatment with low-dose intracoronary alteplase during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) and an ischaemic time ≥4 to 6 h results in increased microvascular obstruction (MVO), a study has shown. Intracoronary alteplase appears to be unsafe for this subgroup.
No association was found between alteplase dose and the extent of MVO (ptrend=0.128), but alteplase increased the mean extent of MVO in patients with an ischaemic time ≥4 to 6 h compared with placebo (alteplase 10 mg vs 20 mg vs placebo: 3.11 percent vs 5.20 percent vs 1.13 percent; ptrend=0.009).
In addition, a statistically significant interaction was observed between ischaemic time and alteplase dose (p=0.018).
A total of 440 patients presenting with STEMI within 6 h of symptom onset (<2 h, n=107; ≥2 h but <4 h, n=235; ≥4 h to 6 h, n=98) and enrolled at 11 UK hospitals between 17 March 2016 and 21 December 2017 were included in this prospective, multicentre, parallel group, randomized, dose-ranging trial. Patients were randomly assigned to treatment with placebo (n=151), alteplase 10 mg (n=144) or alteplase 20 mg (n=145).
Ischaemic time was defined as the time from symptom onset to coronary reperfusion and was a prespecified subgroup of interest. The primary outcome of amount of MVO was quantified by cardiac magnetic resonance imaging at 2–7 days (available for 396 of 440 patients).
“Microvascular obstruction affects one-half of patients with STEMI and confers an adverse prognosis,” the investigators said.