During balloon angioplasty, which is a procedure performed to open a narrowed artery, an interventional cardiologist places a stent in the artery to support it after the blockage has been removed. Over time, healthy heart tissue grows around the stent. Sometimes, however, scar tissue also builds around the stent and leads to new narrowing in the artery. This renewed narrowing is called in-stent restenosis or stent reocclusion.
In-stent restenosis is a type of new narrowing of a formerly blocked artery, so symptoms tend to mimic those of the original problem. These include chest pain and shortness of breath during exercise or exertion. These symptoms, however, do not signal a new heart attack but narrowing caused by built-up scar tissue. Some patients, including diabetics, sense no new symptoms at all.
The treatment for in-stent restenosis depends in part on what type of stent was implanted during the original angioplasty procedure and whether that stent was placed properly. If a stent is inserted in an artery but not expanded fully, more room is left for scar tissue to build up between the stent and the artery wall. In a case such as this, an interventional cardiologist can reinsert a catheter, expand a balloon in the artery and use the stent, now further expanded, to compress scar tissue against the artery wall and ease the restenosis.
Drug-eluting stents slowly release medication to reduce the body’s ability to create new cells that might lead to scar tissue. If a drug-eluting stent was placed properly the first time, a cardiac surgeon might replace it with another type of drug-coated stent. If an uncoated or bare stent was used and placed properly, a new drug-eluting stent might be used. In cases where scar tissue buildup is excessive, a bypass procedure might be considered.
When new stents are placed, patients must observe the same post-procedure drug therapy they used after their first angioplasty procedures. This includes taking low-dose aspirin or prescription antiplatelet medication during the healing period. These medications help prevent blood clots from forming in the new stent as new cardiac tissue grows around it. Some doctors recommend that patients take low-dose aspirin or other medications for the rest of their lives.
Although the rate of in-stent restenosis can be as high as 25 percent, according to some studies, when no stent is used, the rate is even higher. For this reason, most interventional cardiologists use stenting as standard practice during angioplasty and then follow patients closely. Patients who develop in-stent restenosis typically do so within six months of stent placement.