To clear vascular blockage,drug-eluting balloons emerge as stent alternative

Stenting is difficult or impossible for vessels that have a small diameter.

Written by Abantika Ghosh | Published: September 8, 2012 12:04:37 am

Just when stents had seemed to be the final answer to vascular blockage,percutaneous cardiac intervention — range of procedures to remove blockages in blood vessels — has moved to a new form of treatment. Drug-eluting balloons (DEB) are increasingly being used in place of metallic stents to take drugs to the point of the blockage once the clot has been removed.

Stenting is difficult or impossible for vessels that have a small diameter. In such cases,DEBs are the best option and the procedure has become the preferred intervention.

Different from the popular and more conventional use of the balloon in an angioplasty procedure,where the clot is dislodged by an inflated balloon,its use for drug delivery is a recent development preferred because it’s cheaper. A patient on DEBs,unlike stents,doesn’t need to be put on blood thinners for a prolonged period. DEBs are preferred in cases of repeat blockages in vessels which have stents.

“This is a balloon made of a latex or PVC-like material that has the drug wrapped around it through an adsorption technique. The balloon is briefly inflated when being introduced into the vessel and then embedded in the endothelium (inner lining of the vessel) where it keeps releasing the drug slowly to prevent reblockage. In about six weeks,the balloon is washed away so that the vasomotor properties of the vessel,important for preventing blood from clotting while inside the vessel,are not hampered,” Dr Viveka Kumar,senior consultant interventional cardiology and electrophysiology at Max Superspeciality Hospital,Delhi,said.

He has treated about 30 cases so far. “There are about 10-12 centres in the country that offer this treatment at present,” he said.

The procedure would cost approximately Rs 2 lakh if stents are used,DEBs reduce the cost to Rs 1.2-1.4 lakh. More than the cost benefit,the reduced post-operative medication seems to be the key advantage. Metals precipitate coagulation in their vicinity because of their chemical effect on the blood. Balloons have no such effect. With normal stenting,the patient has to take anti-coagulation therapy for at least one year. With balloons,that is just about one month and the chances of bone lesions are lesser. However,there is a debate about the efficacy of balloons in case of blockages in the inner lining of fine cardiac vessels.

Some of the initial trial data was presented at the annual conference of the American Heart Association in Florida last November,where researchers recommended it’s use even for coronary artery blockages.

In a study published in the Journal of the American College of Cardiology a year ago,researchers found promising results of DEBs in patients with restenosis. German researchers selected a group of patients who had a disease of the tibial artery,which is associated with a very high restenosis rate (69 per cent) with standard balloon angioplasty. They were subjected to DEB and after a one-year follow up period,only 9.5 per cent of 104 patients showed signs of reocclusion. “The early restenosis rate of long-segment infrapopliteal disease is significantly lower after treatment with DEBs,compared with historical data using uncoated balloons,” the study concluded.

Dr Aswani Mehta,interventional cardiologist at Sir Ganga Ram Hospital says rates are usually quite high (25 per cent) even in regular balloon angioplasty followed by stenting without any underlying cause for it. “But that is halved with the use of drug-coated balloons. In the last six months or so,we have started using DEBs. All cases have shown very good results,” he said.

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