Invasive Treatment of Mild Heart Attack May Add Risk

As many as half of the 1.5 million Americans who suffer a heart attack each year may be treated too aggressively by cardiologists, raising their risk of death rather than lowering it, researchers said Wednesday.

In new study results that confounded some researchers, the death rate among patients suffering mild heart attacks was one-third higher among those receiving widely used invasive procedures, including angiography, angioplasty and bypass surgery, than among those who received only drugs and supportive therapy, Veterans Affairs researchers told a meeting of the American College of Cardiology in Anaheim.

The results contradict the prevailing wisdom about the treatment of such heart attacks and are likely to stimulate a spirited debate about the value of invasive procedures. The researchers themselves were surprised by the results because they expected to demonstrate that invasive treatments are more valuable.

“We were astonished,” said Dr. William E. Boden of the Veterans Affairs Upstate Health Care System in Syracuse, N.Y. “I hope that physicians will rethink their management approach to patients like this.”

Others suggested that cardiologists who currently feel compelled to use such aggressive treatments may now choose to explore other options. “They can use their clinical judgment,” said Dr. Robert J. Cody of Ohio State University.

“This is an important study that will change the way patients are managed,” added Dr. Adolph Hutter of Massachusetts General Hospital. “And it should do so immediately.”

But Dr. Gregg C. Fonarow of UCLA noted that the aggressive therapy used in the VA study did not incorporate some recent medical advances also described at the cardiology meeting, such as anti-clotting drugs and the use of stents to keep arteries open after the invasive procedures.

Such advances could tip the balance back in favor of more aggressive procedures, he said. “This is not the final word, by any means,” he said.

Boden’s study focused on so-called non-Q-wave heart attacks, relatively mild occurrences that are recognized by their unique electrocardiograms.

In such incidents, which account for about half the 1.5 million heart attacks in this country each year, the heart muscle is not damaged all the way through the heart wall. The arteries feeding the heart are typically not completely clogged either. In the more severe Q-wave heart attacks, the muscle is damaged all the way through its thickness and arteries are completely blocked, producing much more damage.

Since 1987, the American Heart Assn. and the American College of Cardiology have recommended aggressive treatment for non-Q-wave attacks. Typically, surgeons thread a probe through the blood vessels to determine the extent of blockage, a process called angiography.

They then either use angioplasty--inflating a balloon inside the blocked artery to reopen it--or bypass surgery to carry blood around it. Although most surgeons were convinced this was the best approach, the technique had never been evaluated in a clinical trial.

Boden and his colleagues enrolled 920 patients at 15 VA medical centers between 1993 and 1996. Half received the conventional invasive therapy, while the other half received more conservative treatment with medication, unless stress tests dictated surgery.

The study showed that noninvasive evaluation was better than angiography for identifying those patients who need surgical interventions, Hutter said.

After 2 1/2 years, there were 80 deaths and 70 additional heart attacks among the group that received aggressive therapy, compared to 59 deaths and 79 heart attacks among the conservatively treated group--a 36% higher death rate in the invasive group.

The results were especially dramatic in the first nine days of treatment, Boden said. After nine days, there were 21 deaths in the invasive group compared to only six in the conservative group.

Boden thinks the findings will be a shock to the cardiology community. “It is the opposite of what they would expect. I believe the issue here is not whether non-Q-wave patients would not ultimately benefit from [angioplasty or bypasses]. It’s that you shouldn’t be performing routine early invasive intervention on them because you may, in fact, worsen the short-term outcome.”

“All the invasive procedures carry some risk of their own,” Hutter noted. “We may be doing harm in patients who otherwise would have done well.”

While Fonarow agreed that conservative management may be best for some patients with the mildest heart attacks, he noted that new developments may have superseded the study.

Other studies presented at the Anaheim meeting show, for example, that using anti-clotting drugs such as ReoPro and Aggrastat during angioplasty can reduce the incidence of heart attacks and death as much as 50%. Other new treatments can also reduce the likelihood of recurring heart attacks.

“What it means is that we need to do further research and to aggressively apply the more recent developments,” he said.