All of these drugs pose a risk for bleeding complications.
Preventing Artery Narrowing (Restenosis) Over Time
Narrowing or reclosing of the artery (restenosis) can occur within a year of angioplasty or even longer in 15 - 60% of angioplasty patients. Coronary stents, anti-clotting drugs, and other advances have reduced these events significantly, but have not eliminated the problem. Theories for the cause of restenosis include:
- The release of oxidants (damaging unstable particles) at the surgical site may cause injury and activate immune factors that produce cellular overgrowth in smooth muscles of the blood vessels.
- Other activities, including scarring, may remodel and narrow the blood vessels. (This is most likely the reason for restenosis in stented patients.)
Symptoms of restenosis include chest pain on exertion. (Heart attacks, however, do not usually occur with such events.) The narrowing of the artery in this case is not due to blood clots, so anti-clotting drugs are not useful. Restenosis usually requires a repeat operation. A number of approaches, mostly investigative, have been developed to prevent restenosis after angioplasty.
Sirolimus- and Other Drug-Coated Stents. Stents coated with the drug sirolimus (Rapamune), also called rapamycin, are generating great excitement. This drug blocks immune factors that cause cell proliferation and inflammation. It also has antibiotic properties. In an important 2002 study, none of the patients who were given the coated stent experienced reclosure, and 94% of them were free of any adverse heart events. In comparison, 27% of patients in the noncoated group experienced restenosis, while only 71% of them were free of adverse heart events. Researchers are also investigating stents coated with the cancer drug paclitaxel. Studies suggest that these drug-coated stents may be especially important options for patients with diabetes who undergo angioplasty. Patients with diabetes are more likely to experience re-narrowing of the heart arteries than other patients.
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