Emergency bypass surgery or angioplasty procedures to counteract deadly complications that follow some heart attacks not only improve survival odds for cardiogenic shock patients, but the quality of life after such emergency revascularization procedures appears to be better than that of survivors who received less aggressive treatment, according to a new study in the July 19, 2005, issue of the Journal of the American College of Cardiology.
“Although patients with cardiogenic shock are critically ill, most of those who survive their heart attack have good quality of life and physical functioning, and emergency revascularization treatment was a predictor of outcome one year later,” said Lynn A. Sleeper, Sc.D., at the New England Research Institutes in Watertown, Mass. “Cardiogenic shock appears to be an acute systemic disturbance; that is, if the patient survives, the patient typically has good functional status,” said Dr. Sleeper, Sc.D.
Dr. Sleeper noted that this finding differs from what is typically seen in patients with chronic heart failure.
About one of every dozen heart attack patients experiences cardiogenic shock. The heart no longer pumps effectively, leading to a rapid drop in blood pressure and organ failure. Cardiogenic shock is the leading cause of death for people admitted to the hospital with a heart attack, with death ranges historically ranging between 60 percent and 70 percent.
This study analyzed the results of follow-up interviews with surviving participants in the “SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK” (SHOCK) trial. The main trial enrolled cardiogenic shock patients from April 1993 to November 1998 at 30 international sites. The participants were randomly assigned to undergo emergency revascularization (either coronary artery bypass graft surgery or angioplasty) to restore blood flow to the heart muscle or to a control group treated with typical medical stabilization. Patients in the control group had the option of later non-emergency procedures to reopen heart blood vessels.
The SHOCK trial showed that emergency revascularization reduced the death rate at six months to 51 percent. However, cardiogenic shock inflicts heavy damage to the heart, so researchers wanted to know what sort of quality of life the survivors had.
The SHOCK trial survivors completed interviews at two weeks after discharge and at six and 12 months after their heart attacks. Of the patients who survived at least one year, 87 percent reported having either no symptoms or some symptoms, though with the ability to do normal activities with only slight limitations. The overall amount of improvement during the time from shortly after hospital discharge until one year later was similar in both the emergency revascularization group and the group that was initially stabilized medically. However, the patients who underwent the emergency bypass or angioplasty procedures were more likely to be stable (71 percent vs. 44 percent) and less likely to worsen or die (15 percent vs. 34 percent) than the patients who received initial medical stabilization.
“Although approximately half of these patients will die despite aggressive intervention and many days in the intensive care unit, the outcome for survivors of that early period is very rewarding,” Dr. Sleeper said. “The majority of cardiogenic shock survivors have very good quality of life following their heart attack, and treatment with emergency revascularization plays a role in preventing the deterioration of physical functioning.”
However, early revascularization is generally available only in tertiary care centers, accounting for about 15 percent of U.S. hospitals. Dr. Sleeper said that, in 2004, fewer than half of cardiogenic shock patients received an early revascularization procedure.
Although this study was not designed to determine why patients fared better after emergency revascularization, she suggested possible explanations.
“One hypothesis is that the patients treated with emergency revascularization do better because the rapid treatment helps to save more of the heart muscle from destruction following a heart attack,” she said.
The treatment also interrupts the vicious spiral of ischemia (interrupted blood flow) in the parts of the heart muscle served by the coronary arteries.
Dr. Sleeper pointed out that not all survivors were interviewed at all the time points indicated in the study protocol; therefore, the findings may not be applicable to all survivors of cardiogenic shock.
E. Magnus Ohman, M.D., F.A.C.C., at the University of North Carolina in Chapel Hill, who co-authored an editorial in the journal with Patricia P. Chang, M.D., M.H.S., F.A.C.C., called the results of this study rewarding for clinicians.
“The main issue for me is that there’s always been some concern that when you do early revascularization for patients in cardiogenic shock, you might end up saving people to a pretty horrible quality of life,” Dr. Ohman said. “What this study shows is that quality of life among the survivors actually is pretty good.”
The American College of Cardiology, a 33,000-member nonprofit professional medical society and teaching institution, is dedicated to fostering optimal cardiovascular care and disease prevention through professional education, promotion of research, leadership in the development of standards and guidelines, and the formulation of health care policy.