Use of thrombolytic treatment in patients with acute myocardial infarctionin Spain. Observations from the PRIAMHO study

Introduction and objectives. Scarce information is actually available in ou r country regarding the use of thrombolytic treatment in patients with acut e myocardial infarction and how consistently the recommendations of the cli nical guidelines are being implemented. Methods. Cohort study with one year follow-up of patients with acute myocar dial infarction admitted in 24 Spanish hospitals in 1995. Differences in cl inical characteristics and prognosis from patients treated with or without thrombolysis were compared. Results. 2,191 of the 5,242 patients (42%) admitted with an acute myocardia l infarction received thrombolytic therapy (range: 23%-63%). Reasons for ex clusion in the rest were the absence of ST segment elevation (35%), contrai ndications (16%), prehospital delay >12 h (35%), and other causes (15%). Th rombolysis treated patients were at lower risk in general because they had shorter prehospital delays and were younger, more likely to be male, less f requently diabetic, with less prior history of angina or infarction. The av erage delay in administering therapy was of 3 hours while the average in-ho spital delay was 50 minutes and depended only on the hospital where patient s where admitted, as it was shorter in small centers. t-PA was administered in 49% of patients, streptoquinase in 46% and other drugs in 5%. Although t-PA was given more often to younger patients, smokers, anterior and Q-wave infarctions, and to patients with shorter prehospital delays, the determin ant factor was the admission hospital with a frequency ranging from 9% to 9 6%. Patients not treated with thrombolytics had more complications during t he acute phase, and required more invasive procedures. They also had a high er mortality at 28 days (17% vs. 10%, p < 0.0001) and at one-year follow-up (27% vs. 15%, p < 0.0001). Furthermore, a correlation was observed between mortality and delay of treatment application. In multivariate analysis, th rombolytic treatment was an independent predictor of survival at one year, with an odds ratio for mortality of 0.8 (95% CI: 0.66-0.96). Conclusion. Thrombolytic therapy in Spain does not yet conform to the recom mendations of the actual guidelines for the treatment of patients with acut e myocardial infarction because it is underused, especially in high-risk pa tients, the prehospital and in-hospital delays are too long, and a huge var iability exists between hospitals in the frequency and delays of administra tion and selection of the drug that are not sufficiently explained by the c haracteristics of the patients. In spite of this, mortality of treated pati ents was 20% lower in comparison to the nontreated patients, after adjustin g for the other clinical factors with demonstrated prognostic value.