BOSTON — A novel clot-blocking drug appears to significantly improve the success of angioplasty, which is performed on 400,000 Americans annually despite its disappointing failure rate.
If widely used, the medicine potentially could eliminate one-quarter of the repeat procedures now done on about 100,000 people each year.
In this exceedingly common treatment, doctors temporarily inflate balloons inside the heart arteries to push back blockages. However, the arteries frequently clog up again with blood clots, either abruptly within a few days or more slowly in the following months.
As a result, about one-quarter of patients soon need another angioplasty or a bypass operation. This problem has been the major drawback of angioplasty since its introduction almost two decades ago. Doctors have tried many strategies, such as burning the arteries with lasers or propping them open with wire frames, but there has been no easy answer.
The latest approach, tested on 2,099 patients at 56 U.S. hospitals, employs a test-tube-made antibody that prevents the blood’s clotting cells from clumping together.
The medicine is far from a complete solution to angioplasty’s shortcomings: For one thing, it causes bleeding that required 15 percent of the patients to get transfusions. But the research found it reduced angioplasty failure and its complications by one-third after one month and one-quarter after six months.
Dr. Eric Topol of the Cleveland Clinic, principal author of one of two reports being published on the treatment, called it a breakthrough.
The drug, called CentoRx, has not been approved yet for routine use. It was developed by Centocor Inc., a biotechnology firm in Malvern, Pa., that financed the latest study.
The reports on the treatment are being published in this week’s issues of the New England Journal of Medicine and the Lancet, a British journal.
All the patients treated were considered to be at high risk, largely because they had severe chest pain or had suffered heart attacks. Twenty percent to 30 percent of angioplasty patients are in this category.
Doctors randomly gave the patients either CentoRx or dummy shots. The patients were checked for a difference in their risk of death or heart attacks. The doctors also looked at whether they needed bypass operations or repeat angioplasties for newly reclogged heart arteries.
After one month, 8 percent of the CentoRx patients had these complications, compared with 13 percent in the untreated group.
After six months, the risk of these bad outcomes was reduced from 35 percent to 27 percent. The need for repeat angioplasties or bypasses alone dropped 26 percent — from about 22 percent of patients to just over 16 percent.
Dr. Robert Califf of Duke University, another principal author, said the research suggests that for every 1,000 patients who have angioplasties, the new drug will mean 34 fewer heart attacks, 37 fewer emergency bypass operations and 12 fewer repeat angioplasties in the first month after the treatment. Over six months, it eliminates the need for 80 procedures.
The treatment has one significant hazard, however. It causes bleeding in the thigh at the spot where angioplasty tubes are inserted into the body.