Restenosis

Restenosis literally means the reoccurrence of stenosis. This is usually restenosis of an artery, or other blood vessel, but possibly any hollow organ that has been "unblocked". This term is common in vascular surgery, cardiac surgery, interventional radiology, or interventional cardiology following angioplasty, all branches of medicine that frequently treat stenotic lesions.

Coronary restenosis

There are probably several mechanisms that lead to restenosis of arteries. An important one is the inflammatory response, which induces tissue proliferation around an angioplasty site. The inflammatory response can be caused by the balloon expansion used to open the vessel, or if a stent is placed, by the foreign material of the stent itself.

Cardiologists have tried a number of approaches to decrease the risk of restenosis. Stenting is becoming more commonplace; replacing balloon angioplasty. During the stenting procedure, a metal mesh (stent) is deployed against the wall of the artery revascularizing the artery. Other approaches include local radiotherapy and the use of immunosuppressive antiproliferative drugs, coated onto the stenting mesh to form a drug-eluting stent. Analogues of rapamycin, such as tacrolimus (FK-506) and more so everolimus, normally used as immunosuppressants but recently discovered to also inhibit the proliferation of vascular smooth muscle cells, have appeared to be quite effective in preventing restenosis in clinical trials.

Antisense knockdown of c-myc, a protein critical for progression of cell replication, is another approach to inhibit cell proliferation in the artery wall and has been through preliminary clinical trials using Morpholino oligos.

Images of restenosis with bare-metal stents and drug-eluting stents are here