This work was carried out for 6 months at a tertiary care hospital at Miraj. It was a prospective, parallel, randomized and open-labeled study. An approval was obtained from Institutional Ethics Committee. All the patients registered in the ‘In Patient Department’ and ‘Intensive Care Unit’ were screened. An informed, written and signed consent was obtained before enrollment. Patients with severe angina pectoris of either sex within the age group of 35–75 years were included. They were either newly diagnosed patients or having angina at rest or having severe and or frequent episodes of angina.
The following categories of patients were excluded from the study: Patients with increased risk of bleeding, ulcer disease or known gastrointestinal bleeding during last 5 years or those who had a surgery during previous week or a surgery of eye, ear or cerebroneuronal system during previous month or those with known defects of hemostasis, platelet count less than 50% of normal, left bundle branch block or pacemaker electrocardiogram, hypersensitivity to study drugs and pregnant or nursing women. A total of 81 patients fulfilled the inclusion criteria and were selected for the study. They were randomized into two parallel groups. Group I (41 patients) received treatment with dalteparin, 120 IU/kg body weight sc, twice a day for 5 days. Group II (40 patients) received unfractionated heparin initially as an intravenous bolus of 5000 IU followed within two hours by continuous infusion at a rate of 1000 IU/ hour adjusted according to activated partial thromboplastin time (aPTT).
The aPTT was measured 6 and 12 hours after the start of the infusion and daily thereafter. The infusion could be maintained for 5 days or stopped after a minimum of 48 hours and replaced within 8-12 hours with a subcutaneous regimen of unfractionated heparin (12,500 IU every 12 hours).
Aspirin was started in all patients as soon as possible after admission to hospital and continued throughout the study. Other antianginal drugs were started according to standard practice. The patients were followed up at three visits on 1st, 5th and 21st days. A series of resting electrocardiogram were undertaken in all patients on each visit. The primary analysis of efficacy was a comparison of frequency of recurrent angina, myocardial infarction, death and need for revascularization by percutaneous transluminal angioplasty or coronary artery bypass grafting in two study groups. The secondary analysis was a comparison of the composite of the principal outcomes i.e., death, myocardial infarction and recurrence of angina between two study groups. Only one outcome was counted for each patient; where two occurred, death was counted before myocardial infarction, and myocardial infarction was counted before recurrent angina. Angiography was indicated in all patients with refractory angina despite medication. Safety was monitored by studying the parameters like major or minor bleeding, stroke (hemorrhagic, nonhemorrhagic) thrombocytopenia and allergic reactions.
Statistical analysis for efficacy was based on 81 patients with unstable angina pectoris having completed the study. The efficacy parameters tested were frequency of recurrent angina, myocardial infarction, death and need for revascularization procedures and composite outcome of death, myocardial infarction and recurrent angina. Statistical analysis for safety was based on 81 patients (40 on unfractionated heparin and 41 on dalteparin) enrolled in the study. Z-test was applied for the analysis of efficacy and safety results and group comparisons. P-value<0.05 was considered statistically significant.