Hypotension in acute myocardial infarction patients given streptokinase.

OBJECTIVE

This is a prospective cohort study done over a period of one year to look at hypotension that developed in the local Acute Myocardial Infarction (AMI) patients given Streptokinase (SK).

METHOD

Suitable patients with AMI (those with ischaemic chest pain most severe within the last 8 hours, ST-segment elevation and no contraindications) were selected for thrombolysis with SK given as the standard dose of 1.5 mega-units diluted in 100 mls of normal saline and infused over 60 minutes. (Group A). The AMI patients who did not receive SK (Group B), were analysed separately and acted as "controls", as it was not possible to withhold thrombolytic therapy in a group of patients in a completely randomised fashion. The pulse, non-invasive blood pressure and electrocardiogram were monitored and recorded.

RESULTS

Of 120 patients analysed, 70 received SK (Group A) and 50 (Group B) did not due to a variety of reasons. There was no statistically significant difference in the sex, age and body weight distribution as well as the initial mean arterial blood pressure (MAP) in the two groups. The MAP showed a statistically significant decrease at 15 minutes (105.6 to 81.4 mmHg, 95%CI: 13.965, 28.178) and 30 minutes (105.6 to 89.6 mmHg, 95%CI: 10.929, 19.814) after the commencement of SK in Group A patients. When analysed separately, the decrease in MAP was also statistically significant at 15 minutes (95%CI: 4.263, 22.014) for those with anterior AMI and both at 15 (95%CI: 19.112, 41.299) and 30 minutes (95%CI: 1.191, 28.716) for those with inferior AMI. There was no statistically significant decrease noted in Group B patients and the door-to-needle time for Group A patients was 37.2+/-6.0 minutes. The SK infusion time for Group A patients who developed hypotension was prolonged to 95.3+/-14.1 minutes.

CONCLUSION

Hypotension was more commonly noted in the AMI patients given SK. The MAP tend to decrease in the first 30 minutes after commencing the SK infusion. It is thus possible to conclude that the hypotension was at least partly due to SK and is probably a rate-related phenomenon.