The potential impact of local intracoronary infusion of streptokinase (SK) on vascular prostaglandin synthetic pathways was studied in a canine model. Control animals (n = 10) underwent left coronary artery (LC A) infusion of50,000 units SK for 90 minutes; experimental animals (n = 10) underwent LC A infusion of normal saline. Plasma samples for radioimmunoassay (RI A) of prostacyclin (PGI-2) and thromboxane (TXA-2) were obtained from the coronary sinus (CS) as follows: One sample pre infusion, six samples during infusion, and three samples post in fusion in each animal. Comparisons between control and experimental plasma levels of PGI-2 and TXA-2 were made for each sampling time. The PGI-2 levels remained at or below the lower limits of detect ability by RIA (the most sensitive assay available) in both control and experimental animals. TXA-2 levels were higher in experimental than in control animals at all sampling times, with the most significant differences occurring in samples 3 (after 30 minutes of infusion,.001 <P <.01), 4 (after 45 minutes of infusion,.05 <P <.10), and 5 (after 60 minutes of infusion,.02 < P <.05). We suggest (1) it is unlikely that any of the beneficial effects of coronary streptokinase infusions are PGI-2-mediated, (2) that the TXA-2 increases in our model may represent a patho physiologic-biochemical correlate of previously identified morphologic evidence of endothelial damage in animals infused with fibrinolytic agents, and (3) that our findings may indicate that fibrinolytic infusions produce competing effects: Lysis of thrombi and endothelial injury with TXA-2 production. Investigation into a possible dose response relationship and possible adjunctive use of antiplatelet drugs, antithromboxane drugs, and calcium channel blockers is warranted.
- Animal studies
- Coronary arteries
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology