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First ‘absorbable’ heart stent opens new era in treating heart disease

Published:Wednesday | September 7, 2016 | 9:00 AM
The new 'absorbable' heart stent.

The United States Food and Drug Administration (FDA) this month approved a new absorbable heart stent to treat coronary artery disease. It is the first on the market that dissolves over time, and it will advance the treatment of coronary artery disease to the next level, noted doctors at Miami Cardiac & Vascular Institute, who took part in ground-breaking trials leading up to the FDA's action.

The short name for the new stent is Absorb, and it's a fitting moniker. The stent, or scaffold as cardiologists call it, is manufactured by Abbott Laboratories from a biodegradable polymer, similar to material used in other types of absorbable medical devices such as sutures.

The potential advantages to such an absorbable stent include less scar-tissue development in the treated arteries and fewer other complications. The older metallic devices remain permanently inside the body and can increase the risk of blood clots or cause complications as a patient ages.

DISSOLVES IN THREE YEARS

Like other available stents, Absorb releases a drug over time to treat the narrowed artery. Such drug-eluting stents were first approved more than a decade ago, but the non-metallic Absorb device takes the treatment of artery disease another step forward by completely dissolving within two to three years after it is deployed.

The Institute was the only South Florida medical facility to take part in the Absorb trials.

"We also had the opportunity to participate in cases outside of the United States in Europe," said Ramon Quesada, MD, Medical Director of Interventional Cardiology, Cardiac Research and Structural Heart Program at the Miami Cardiac & Vascular Institute at Baptist Hospital.

"We got involved in more complex cases than the ones we were doing traditionally under the trial, so the potential of this new technology, and this is the first generation, is really exponential. This is changing the whole spectrum of coronary intervention."

Coronary heart disease is responsible for about 370,000 deaths each year in the US, according to the National Heart, Lung, and Blood Institute. The condition develops when cholesterol-containing deposits build up and narrow the coronary arteries, decreasing blood flow to the heart.

Dr Quesada was the principal investigator for the Absorb stent trials at the Institute. Other participating Institute physicians were Marcus St John, MD; Ramon Lloret, MD, Rajesh Dhairyawan, MD; Alvaro Gomez, MD; and Bernardo Lopez Sanabria, MD.

The FDA's approval was based on the findings of a 2,008-person study of US heart patients. The Absorb study found that 7.8 per cent of patients treated with the new device suffered "a major cardiac adverse event," a rate that was "clinically comparable" to the 6.1 per cent rate for those treated with a drug-coated metal stent.

For now, some patients with coronary artery disease will not be candidates for the biodegradable plastic stent. Absorb should not be inserted in patients who are allergic to the material used to make the device, those who are sensitive to the contrast agents administered before the stent is implanted, or those who cannot take blood-thinning drugs for long periods, the FDA said.

'FOURTH REVOLUTION'

Dr Quesada refers to the development of the absorbable stent as the "fourth revolution" in treating coronary artery disease. The first involved opening arteries with balloons via angioplasty procedures. The second introduced metallic stents, or small mesh tubes, which can create problems by leaving scar formations. The third revolution, he explains, introduced the drug-releasing stents to help combat scarring.

"This new (fourth revolution) technology has a drug-eluting stent or a scaffold, but the difference is that it will be reabsorbed and disappear completely," explained Dr Quesada.

"Why is that important? It's important because we restore the natural function of the artery. And we can revascularise the artery with this stent, and within three years, the artery will be free of any foreign body."