For all the leaps and bounds in medical science, it’s easy to overlook the stumbling blocks left in their wake. Take clogged arteries, for instance. Over the last few decades, we’ve learned how to unclog them without using a scalpel. In variations of angioplasty, a noninvasive alternative to coronary bypass surgery, tiny balloons, lasers or delicate drill-like instruments are used to smooth away plaque buildup. In some cases, miniature scaffolds called stents are inserted to keep newly opened arteries propped wide. But despite these remarkable advances, restenosis (reblockage) occurs in some patients who undergo angioplasty.
Experts aren’t sure exactly why arteries close up again, but they do know how it happens. Very soon after angioplasty is performed— within days or sometimes even hours of the procedure—the treated arteries start springing back to their original, narrowed position. This process is called recoiling. Over time, further changes in the artery wall cause the vessels to narrow even more, a process called remodeling.
In addition, restenosis can arise from the trauma of angioplasty itself. Reacting as if the treated artery had been injured, the body sends blood to the area, where it clots just as it would at the site of a wound. Clotting blood contains thrombin, a substance that attracts smooth muscle cells to repair the “injured” artery wall. In the case of restenosis, the healing process goes too far. Too much new tissue accumulates in the vessel, causing the artery to become narrow again.
Because restenosis requires repeat angioplasty, the insertion of a stent or possibly bypass surgery, researchers have been studying ways to prevent or at least stall the renarrowing process. So far, they say these strategies are important:
- Drug-releasing stents. The tiny scaffoldlike devices are placed at the site of the reblockage, where they release drugs, hormones or even low doses of radiation designed to foil the restenosis process.
- Anti-growth drugs. These medications scramble the genetic code that promotes tissue growth at the site of a wound.
- Anti-platelet drugs. These drugs discourage the buildup of platelet cells within the affected artery.
Often a silent process, restenosis sometimes becomes apparent only during follow-up testing after angioplasty. That’s why anyone who has had angioplasty should be closely monitored by his or her doctor and immediately report any suspicious symptoms, such as chest pain or a recurrence of chest pain similar to that experienced before the procedure.