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Health & Medicine

2002-11-01 14:20:00

Artery blockage

:  What are the latest and most non-invasive ways to correct a blockage in an artery?

ANSWER:  Previously when arteries were blocked in various parts of the body the only way to correct the blockage was to do something known as endarterectomy where by the plaque narrowing the artery was actually cut out and removed, or to bypass the blocked arteries using another structure such as a vein from the leg.  It was soon learned that cutting the plaque out of a smaller artery, such as a coronary artery, was fraught with great danger and often resulted in acute blockage of the artery.  Thus, bypass procedures became very common in the late 1960s and remain an important way of treating patients with coronary blockages.  Blockages in larger arteries may be bypassed, still, but vessels, particularly the arteries in the neck, are more amenable to endarterectomy or plaque removal.  Beginning in the late 1970s and early 80s, more non-invasive approaches have been attempted and have met with enormous success.  The first procedure to remedy blockages within arteries was performed by Dr. Andreas Gruntzig in Zurich, Switzerland in 1977.  He was able to pass a small balloon through an artery that was narrowed in the heart and expand the balloon resulting in improved blood flow and less restriction in the area of plaque formation.  This procedure quickly became known as balloon angioplasty, or PTCA (Percutaneous Transluminal Coronary Angioplasty).  This procedure has spawned a tremendous amount of investigations dealing with plaque removal and restoration of blood flow in blocked arteries.  We quickly became enamored of the idea of using clot busting drugs to open up arteries that were completely blocked and then doing a balloon procedure.  Later, much work was done with lasers to open arteries, and a procedure known as a Rotablator was performed where some of the plaque was actually ground away and it restored blood flow.  None of these techniques, however, resulted in long term improvement.  The latest, and by far the safest mechanism for non-surgical interventions in blocked arteries is to combine the balloon procedure with a stent.  In this procedure, the area of plaque formation, which has caused the artery to narrow, is either balloon dilated first, or, at the same time as the stent is implanted, the lesion is crossed, a balloon is expanded and the small wire mesh stent is left to scaffold the artery and keep it open.  This has resulted in several wonderful improvements in an angioplasty procedure.  First of all, the safety of this procedure has gone up immensely because in the simple balloon procedure a number of patients had to go to surgery emergently because the artery would not stay open.  This problem has virtually been eliminated by the use of stents.  Secondly, and perhaps more importantly, is the fact that the rate of restenosis, or recurrence of blockage, has fallen from about 42% with a simple balloon procedure now to the range of about 22%.  This nearly 50% reduction in restenosis has made this procedure more viable for the long term and more attractive to a greater number of patients.  On the horizon are yet new improvements in the stent procedure.  Stents have been developed which are coated, and the coated stents have a much lesser recurrence rate decreasing the rate of restenosis in early investigations in the range of five to 7%.  In some studies, the restenosis rate has approached 0% at the end of one year.  Certainly, the future looks to be very bright in the area of coated stents, and is an area that we are quite enthusiastic about doing research.  It only stands to reason if the restenosis becomes lower and if there is a virtual 0% risk of blockage or clot formation within the stent that more difficult lesions will be approached and many patients who ordinarily would have had bypass surgery will benefit from this non-invasive procedure