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Angioplasty is preferred treatment for acute coronary syndrome (Published 8/24/2003)

If one suspects they are suffering a heart attack, they need to get to the nearest emergency room where the diagnosis can be confirmed or denied. If the diagnosis of acute coronary syndrome is made, an angioplasty is the preferred treatment, according to an important study published recently in the New England Journal of Medicine.

The study provides the clinical proof of physiologic principles that have been known for about two decades. A Danish study surveying the outcome of patients treated by rapid balloon dilation of a closed blood vessel fared better than those treated by clot-busting drugs.

First, the fundamental ideas are important to review. A heart attack results when the blood supplying oxygen and nutrients to the very demanding heart muscle is interrupted. What was speculated in the late 1970s was that even if the blood vessel is irrevocably closed, the heart attack is not an "all or none" phenomenon. That is, the heart tissue takes some time to actually die. Moreover, most heart attacks are not abrupt closures. The process of closing of a coronary blood vessel has starts and stops.

Mostly because of lipid-induced injury to the walls of blood vessels, inflammatory and physical triggers can cause partial clots to form that may obstruct the blood flow. The blood vessel can call for help from clot-dissolving chemicals the body naturally makes, so the back-and-forth battle rages until the wall injury can stabilize in a partially open state, or the clot wins and the blood vessel is essentially obstructed enough to compromise the heart muscle.

The clinical mantra of "no flow, no hope" evolved, so the "open vessel" paradigm was established. Presumably, the idea was the sooner, the better. Excellent medications were developed to hopefully aid the body's ability to dissolve clots, tipping the battle in favor of clot dissolution.

A more elaborate and expensive approach was to open coronary arteries directly with tiny balloons that would physically push open the clotted and damaged plaque material to restore blood flow.

Besides the technical issues involved with coronary angioplasty, a major limiting factor with the balloon technique was assembling the required team and getting the catheterization laboratory open. This was especially a problem since most coronary events occurred at night and early in the morning.

Cost and staffing issues caused even some major hospitals to limit these options to routine working hours, which was a real headache since emergencies would disrupt routinely scheduled operations.

Clearly, this option was not even available for patients who lived near a hospital that did not have the capability of doing angioplasty in the first place.

The Danish study demonstrated that transfer to a facility capable of urgent angioplasty reduced the risk of death and major related complications by about 40 percent.

Of the 1,129 patients in this study, 14 percent of those treated with drugs alone died, had another heart attack, or suffered a stroke, compared with 8 percent if they were transferred to a facility for acute angioplasty.

A major caveat was that in this Danish study, most transfers were made within two hours. This time interval clearly is a pivotal factor in achieving benefit.

In the United States, about half a million heart attacks occur annually. Most of those who die actually do so before they get to the emergency room. Of those who get to a hospital, only about 20 percent will get an angioplasty because only about 15 percent of hospitals are equipped to do angioplasty.

Keep in mind that it is clinically important to be able to have cardiac surgery available as well, in case the angioplasty attempt fails to open a critical blood vessel that feeds a critical amount of heart muscle. Quality of life and survival itself depend greatly on how much heart damage results from the heart attack.

If the facility does not have the capability of doing angioplasty, and the process of transferring is awkward, i.e., time-consuming, then the clot-dissolving medications need to be used with stabilization, and transfer to a cardiac center done when possible. This Danish study illustrates that time is important. Patients need to be transferred expeditiously with ambulances capable and staffed to act as mobile acute cardiac care units.

Hospitals and invasive cardiologists need to be prepared to accept these patients 24/7, and cardiac surgery similarly needs to be on standby.

Regionalization of cardiac care should be accomplished to ensure that enough volume of cases keeps skills honed.

I fear that this study may cause smaller hospitals to build angioplasty laboratories to avoid losing lucrative cases.

This may result in laboratory overutilization, which would raise health-care costs, and individual facility and physician underutilization, which could reduce the probability of good patient outcome.

Intelligent management of health-care resources is required, with "intelligent" being the operative word.

It's time for communities to get involved. This issue should not be left up to corporate interests.

-- Irving Kent Loh, M.D., is medical director of the Ventura Heart Institute in Thousand Oaks. His e-mail address is iklmdvhi@aol.com.

 

 
   
   

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