However, an important study published in 1999 by a group led by Judith S. Hochman, M.D., showed aggressive invasive treatment of heart attack patients who develop cardiogenic shock could save lives and as a result, the American Heart Association and the American College of Cardiology recommend aggressively treating heart attack shock patients.
Although aggressive therapy is increasingly used in tertiary care hospitals, which have sophisticated invasive care facilities, not all eligible patients receive it. And most patients who reach a hospital without such facilities are not transferred to a hospital where they can be treated appropriately.
Now, a new study by Dr. Hochman's group demonstrates that some patients who quickly received invasive treatment with angioplasty or open-heart surgery to bypass clogged coronary arteries survive long-term, and the superiority of this treatment is sustained over time.
They report in the June 7 issue of the Journal of the American Medical Association that with invasive treatment 33% of hospitalized heart attack patients with cardiac shock were alive six years later. By comparison, only 20% of shock patients who were treated initially with medications and a device to support the circulation called an intra-aortic balloon pump (IABP) survived long-term.
'This well conducted study clearly shows that treating the sickest heart attack patients early and aggressively provides a survival benefit that is sustained years after treatment,' says Elizabeth G. Nabel, M.D., Director of the National Heart, Lung, and Blood Institute. 'These results should guide physicians to consider emergency revascularization for patents with cardiogenic shock complicating heart attack,' says Dr. Nabel.
'Our study shows a significant survival benefit that is sustained up to 11 years. This benefit extends even to selected patients over the age of 75,' says Dr. Hochman, Clinical Chief of the Leon H. Charney Division of Cardiology and Director of Cardiovascular Clinical Research at New York University School of Medicine. 'Patients can do very well and clearly benefit from this therapy, but many doctors are reluctant to treat shock patients aggressively because they are the sickest of the sick and the death rate is so high,' says Dr. Hochman, who is also the Harold Snyder Family Professor of Cardiology at NYU School of Medicine.
Another problem is that many shock patients need to be put into an ambulance and transferred to tertiary care centers where they can receive appropriate care. Doctors usually have to accompany these patients to another hospital, and Dr. Hochman says 'there is a lot of legitimate fear about putting very sick patients in an ambulance.' Tertiary care hospitals provide specialized services such as catheterization labs where angioplasty, which involves threading a catheter-tipped balloon to the site of a blockage in a coronary artery, is performed.
Only about 60 percent of shock patients younger than 75 received the more aggressive treatment in tertiary care centers in 2004, according to a previous study by Dr Hochman and colleagues. And only 38 percent of patients with shock were transferred to such centers from 1998 to 2001.
The latest report from Dr. Hochman's group stems from an international trial funded by the National Heart, Lung, and Blood Institute called SHOCK, which enrolled 302 patients between 1993 and 1998 at 29 tertiary care centers. All patients were initially treated with medications and IABP to support the circulation and half received immediate angioplasty or bypass surgery. Patients in the medications arm of the trial could undergo angioplasty or bypass surgery at least two days later. One year after treatment, 47 percent of the patients who received the invasive treatments immediately were alive compared to 34 percent of those in the medications group.
Dr. Hochman hopes that more patients with cardiogenic shock will be treated aggressively and she sees some progress. In January the New York State Department of Health began a two-year experiment in which heart attack patients with severe shock would be analyzed separately from the public databases.
Already Dr. Hochman says that she has heard from colleagues that more cardiogenic shock patients are undergoing angioplasty and surgery in New York because physicians aren't worried about raising their publicly reported surgical and angioplasty mortality rates due to treating many shock patients.
The change was in response to a number of publications that suggested bias by New York physicians against doing invasive procedures in these highest risk patients. One study by Dr. Hochman and colleagues from Albert Einstein College of Medicine and New England Research Institutes showed that shock patients in New York were less likely than patients in other states to be treated aggressively, presumably because of public reporting requirements. The study's findings were reported at a meeting last year of the American Heart Association.
Research is underway to find new treatments for cardiogenic shock. Dr. Hochman is leading a trial to determine whether a compound called nitric oxide synthase inhibitor can help shock patients by targeting excess nitric oxide production.