Ridogrel does not increase the speed and rate of coronary recanalization in patients with myocardial infarction treated with alteplase and heparin.

Ridogrel, a compound with the dual property of inhibiting the synthesis of thromboxane and blocking the receptors of thromboxane/prostaglandin/endoperoxides, has been shown to accelerate the speed of recanalization and to delay or prevent reocclusion during systemic thrombolysis with tissue plasminogen activator in experimental animals. Ninety patients who had not taken any antiplatelet drugs within the last 10 days were randomized to either intravenous ASA 250 mg immediately before the thrombolytic treatment and 100 mg once a day orally thereafter or ridogrel 300 mg i.v. before thrombolytic treatment and 300 mg b.i.d. orally thereafter. All patients were given intravenous heparin concomitantly with alteplase. The patency of the infarct-related artery was determined by coronary angiography before the administration of the thrombolytic agent and by repeated coronary angiography every 15 min until the end of the administration of alteplase. A final angiogram was obtained 48 to 72 h later. At 90 min, the recanalization and patency rates were the same in the two treatment groups with no intergroup difference in the speed of recanalization.

Coronary recanalization rate after intravenous bolus of alteplase in acute myocardial infarction.

The demonstration in animals that recombinant tissue-type plasminogen activator produces prolonged thrombolysis after its clearance from the circulation has prompted a few pilot studies of bolus administration in patients. Alteplase (bolus dose of 70 mg) resulted in the highest recanalization rate in our previous pilot study comparing bolus doses of 50, 60 and 70 mg of alteplase in patients with acute myocardial infarction. The aim of the present trial was to assess the efficacy and safety of the same bolus dose in a larger number of patients. A further objective was to study the angiographic reocclusion rate at 12 to 24 hours in patients who had a recanalized infarct-related coronary artery at 90 minutes and were randomized at that time to a bolus dose or an infusion for 3 hours of 30 mg of alteplase. Sixty patients with acute myocardial infarction and angiographically documented total occlusion of the infarct-related coronary artery before thrombolysis were treated within 5 hours of onset of symptoms with an intravenous 70-mg bolus dose of alteplase (or 80 mg if body weight was greater than or equal to 90 kg). Each patient received 5,000 IU of heparin intraarterially and 100 mg of aspirin by mouth before administration of alteplase. Coronary angiography was repeated 60 and 90 minutes after alteplase administration. The recanalization rate of the infarct-related coronary artery was 55% (95% confidence interval, 43 to 66%) at 60 minutes and 48% (95% confidence interval, 37 to 60%) at 90 minutes. Pretreatment levels of lipoprotein (a) were not significantly related to recanalization.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of high-frequency analysis of signal-averaged surface electrocardiograms in acute myocardial infarction before and after coronary thrombolysis for assessing coronary reperfusion.

The incidence of late potentials on the signal-averaged electrocardiogram before and after coronary thrombolysis was studied in 54 patients with an acute myocardial infarction of less than or equal to 5 hours' duration and with an angiographically documented total occlusion of the infarct-related coronary artery on admission. A significant (p = 0.038) 50% relative reduction in the incidence of late potentials was observed in the group of 35 patients who underwent reperfusion: from 16 of 35 (46%) before to 8 of 35 (23%) at 120 minutes after the start of thrombolytic treatment. No significant reduction was seen in the 19 patients in whom thrombolysis was unsuccessful: from 8 of 19 (42%) before to 7 of 19 (37%) afterward. Despite successful recanalization, late potentials persisted or newly developed after thrombolytic therapy in 8 of 54 patients (15%). It is concluded that successful thrombolysis reduces the incidence of late potentials on the signal-averaged electrocardiogram but that the sensitivity and specificity of this finding are not high enough to allow reliable monitoring of coronary reperfusion at the bedside.