Author + information
- Received June 2, 1993
- Revision received September 24, 1993
- Accepted September 30, 1993
- Published online March 1, 1994.
- Richard M. Prewitt, MD, FRCPC∗,
- Shian Gu, MD,
- Usha Schick, BSc and
- John Ducas, MD, FRCPC
- ↵∗Address for correspondence: Dr. Richard M. Prewitt, Health Sciences Centre, Department of Medicine, Section of Cardiology, 700 William Avenue, GF223, Winnipeg, Manitoba, R3E 0Z3 Canada.
Objectives. The 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 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 ~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 diastollic 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.
☆ This study was supported by the Heart and Stroke Foundation of Canada, Ottawa. Ontario, Canada.
- Received June 2, 1993.
- Revision received September 24, 1993.
- Accepted September 30, 1993.