Despite advances in treatment, people with a myocardial infarction who survive the first hit and get to a hospital remain in danger. Almost one out of 10 of these patients will develop cardiogenic shock in which the heart malfunctions, causing an inadequate amount of blood to be pumped to the vital organs. As blood pressure plummets, the skin becomes cool and the body's organs shut down. Some 60% of these patients will not survive, which is why cardiogenic shock is the leading cause of death for myocardial infarction patients once they reach the hospital.

However, an important study published in 1999 by a group led by Judith S. Hochman, showed aggressive invasive treatment of myocardial infarction patients who develop cardiogenic shock could save lives and as a result, the American Heart Association ( AHA ) and the American College of Cardiology ( ACC ) recommend aggressively treating cardiogenic 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 study by Hochman's group has demonstrated 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 have reported in the Journal of the American Medical Association ( JAMA ) that with invasive treatment 33% of hospitalised myocardial infarction patients with cardiogenic 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 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, director of the National Heart, Lung, and Blood Institute ( NHLBI ). " These results should guide physicians to consider emergency revascularization for patients with cardiogenic shock complicating myocardial infarction," says 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 Hochman, 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 Hochman.

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 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 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 Hochman and colleagues. And only 38 percent of patients with shock were transferred to such centers from 1998 to 2001.

The latest report from 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.

Source: New York University Medical Center and School of Medicine, 2006

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