Heart attack survival in patients given thrombolytic therapy -- clot-busting drugs -- is boosted dramatically when doctors also use a pump device that is already commonly available in hospital emergency rooms and cardiac intensive care wards to aid in the pumping of blood, according to a study presented at the recent American College of Cardiology meeting in Atlanta.
To obtain the findings, Hal Barron, MD, assistant professor of medicine with the division of cardiology at the University of California San Francisco and associate director of cardiovascular research at Genentech Inc. of South San Francisco, Calif., evaluated survival of heart attack patients.
Sixty-nine percent of patients who received thrombolytic therapy without the pump died in the hospital, whereas only 49 percent who were treated with the pump in addition to clot-busting drugs died, Barron found. In contrast, death rates in patients given emergency angioplasties to clear coronary arteries were 44 percent with the pump and 47 percent without, not a significant difference according to Barron.
The senior scientist on the study, Tony Chou, MD, assistant professor of medicine and acting director of the cardiac catheterization lab at UCSF, suggests that angioplasty is emerging as a treatment of choice for most emergency heart attack patients.
However, Chou notes, "Many hospitals in the United States, especially in rural areas, do not offer angioplasties as an option. On a nationwide basis, the use of the intra-aortic balloon pump in combination with clot-busting drugs at these hospitals has the potential to save thousands of lives each year."
The pump treatment, called intra-aortic balloon counterpulsation, requires that an emergency room physician or intensive-care cardiologist place the balloon into the aorta by pushing it through a thin flexible tube that is inserted through an artery in the groin and threaded upward into the aorta. Once the balloon is in place, a pump is used to expand and contract it. When the balloon expands, it helps improve delivery of oxygenated blood to all the body's tissues and to the heart muscle itself.
To conduct the retrospective study, the researchers used the National Registry of Myocardial Infarction 2, a data base maintained by Genentech. The researchers identified 21,718 patients who had acute heart attacks and who arrived at the hospital with cardiogenic shock or else developed the condition while in the hospital. Of the 21,178 patients studied, 6993 received the balloon pump treatment.
Cardiogenic shock is a life-threatening condition in which, as a result of the heart's failure to pump, blood pressure drops too low to maintain the functioning of other organs. More often than not, cardiogenic shock leads to death.
Barron says use of a pump may improve delivery of a thrombolytic drug to the site of heart-attack causing clot, thereby boosting prospects for breaking up the clot and restoring blood flow to the oxygen-starved heart.