Intraaortic balloon counterpulsation enhances coronary thrombolysis induced by intravenous administration of a thrombolytic agent.
OBJECTIVE
This study was designed to test the hypothesis that in the presence of moderate hypotension, intraaortic balloon counterpulsation would enhance coronary thrombolysis induced by intravenous administration of recombinant tissue-type plasminogen activator (rt-PA).


BACKGROUND
Although many studies have confirmed the efficacy of thrombolytic therapy in acute myocardial infarction, few have systematically investigated the effects of alterations in aortic pressure on coronary thrombolysis, and none have previously investigated the effects of intraaortic balloon counterpulsation on thrombolysis.


METHODS
The effects of intraaortic balloon counterpulsation on aortic pressure, coronary blood flow and coronary thrombolysis were studied in a canine model. Coronary thrombosis was induced in eight dogs by injection of radioactive blood clot through a catheter placed in the left anterior descending coronary artery. Subsequently, dogs underwent phlebotomy to decrease systolic aortic pressure to approximately 90 mm Hg. After phlebotomy, during a 15-min interval of intravenous administration of rt-PA, coronary thrombolysis and coronary flow were determined during and in the absence of counterpulsation.


RESULTS
Intraaortic balloon counterpulsation significantly increased aortic diastolic pressure. Corresponding to the increase in pressure, intraaortic balloon counterpulsation significantly increased the rate of rt-PA-induced coronary thrombolysis. Although not statistically significant, peak diastolic coronary flow tended to increase with counterpulsation.


CONCLUSIONS
These results indicate that in the presence of moderate systemic hypotension, intraaortic balloon counterpulsation enhances the rate of rt-PA-induced coronary thrombolysis.
Prewitt
R M
RM
Department of Medicine, University of Manitoba, Winnipeg, Canada.
Gu
S
S
Schick
U
U
Ducas
J
J
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D003326:Coronary Circulation / Q000502:physiology; D003328:Coronary Thrombosis / Q000188:drug therapy* / Q000503:physiopathology / Q000628:therapy; D004285:Dogs; D007022:Hypotension / Q000503:physiopathology*; D007423:Intra-Aortic Balloon Pumping; D009200:Myocardial Contraction / Q000502:physiology; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*
D010959:Tissue Plasminogen Activator