Patients who received tirofiban before angiogram also had a reduction in thrombus and occlusions.
Early initiation of tirofiban (Aggrastat, Merck) during transport significantly improved outcomes in patients with acute MI, who are candidates for angioplasty in the On-TIME trial.
Harry Suryapranata, MD, PhD, from the ISALA Klinieken at the Hospital de Weezenlanden in Zwolle, The Netherlands, presented the results of the trial at late-breaking clinical trials session. ¡°The safety profile of tirofiban makes it attractive for early facilitation of percutaneous coronary intervention (PCI) in patients with acute MI, who are being transferred to a PCI center¡±, he said.

The On-TIME trial was designed to compare the effects of tirofiban initiated before patients reached the hospital with the effects of initiation of therapy in the catheterization lab. The primary endpoint of the study was TIMI-3 flow at the initial angiogram. Data were available on 487 patients. Patients were eligible if they presented with an acute MI showing ST elevation in at least two leads, had chest pain for more than 30 minutes and were able to have a PCI within six hours of symptom onset. These patients were identified in the ambulance or referral center and randomized to tirofiban at a dose of 10 mg/kg bolus with a 0.15 mg/kg/min infusion or placebo before continuing to a PCI center. After the initial angiogram, patients in the placebo group received a second bolus that was tirofiban, not placebo. Patients in the tirobiban group received a second bolus, this time a placebo. There were 243 patients who received tirofiban before the initial angiogram and 244 patients who received it after the angiogram. All patients then received a PCI, followed by open-label tirofiban.

Patients who received tirofiban early had a significant improvement in infarct-related vessel patency (TIMI-2 or TIMI-3), Dr. Suryapranata said. In the early group, 43% of patients had TIMI-2 or TIMI-3 flow, compared with 34% of patients in the late group. Those improvements occurred across all patient subsets, including age, gender, presence of diabetes, infarct location, smoking status, time to presentation and time before treatment, he added. There were also significant differences at the initial angiogram, according to the study. The incidence of thrombus and fresh occlusions was higher among patients who did not receive tirofiban prior to the angiogram. The combined incidence of thrombus and occlusions was 73% in the late treatment group and 60% in the early treatment group. Dr. Suryapranata and his colleagues also looked at clinical outcome at 30 days. Among all patients, the incidence of death, recurrent MI, stroke and major bleeding was 3.1%.