[Behavior of arterial pressure during administration of intravenous streptokinase, in patients with acute myocardial infarct].

OBJECTIVE

To evaluate the effect on blood pressure (BP) of intravenous (IV) streptokinase (SK) in patients (PTS) with acute myocardial infarction (AMI).

DESIGN

Retrospective study with analysis of BP registers ten minutes before and during SK infusion.

SETTING

PTS admitted to the Coronary Care Unit (CCU) of Santo António Hospital, Oporto.

PATIENTS

Thirty-eight male PTS, average ages of 54, ranging from 38 to 67, AMI confirmed, and criteria to thrombolytic therapy. One patient was excluded on account of persistent hypotension since admission.

MATERIAL AND METHODS

IV infusion of 1,500,000 U of SK over 60 minutes, preceded by 200 mg IV of prednisolone. BP and heart rate (HR) were evaluated with a Datascope Accutorr 1A set. The lowest value of the systolic BP (SBP) recorded ten minutes before SK infusion was considered the baseline value. We valued the reduction of SBP above 15%, defining its fall as the difference between the baseline value and the minimum value of SBP recorded during the infusion. Hypotension was defined to SBP values below 90 mmHg.

MAIN RESULTS

The SBP fall was 40.4 +/- 22.1 mmHg (range 9 to 102), having been recorded the minimum value at 22.9 +/- 10.9 minutes. It was accompanied by diastolic BP (DBP) fall of 30.6 +/- 18.9 mmHg (range -2 to 76) and by a HR increasing from 76.2 +/- 13.7 beats/min. to 80.8 +/- 14.1 beats/min. (p less than 0.01). In 86% of the PTS this fall was transient, lasting 8.9 +/- 6.3 minutes, and was corrected by slowing or stopping the infusion for a few minutes and placing the patient in Trendelenburg position. Two PTS needed sympaticomimetic amines because of persistent BP reduction despite the previous measures. 92% of the PTS had a SBP fall higher than 15% in relation to the baseline value. The SBP was kept over 90 mmHg in 20 PTS (54%); hypotension was recorded in the remaining 14 PTS (38%), and in 10 (27%) of these the SBP fell below 80 mmHg. We couldn't prove that the infarction location and the extension of the ischemic lesion had influenced this BP fall.

CONCLUSION

The BP reduction during treatment with high doses of SK deserves some attention because, although transient and easily reversible, it is frequent and sometimes significative. It demands then careful monitoring in order to avoid the hypoperfusion to the ischemic myocardium, that could jeopardize the potential benefits of reperfusion in the reduction of infarction area, the main objective of the thrombolytic treatment.