Page 476 - Textbook of Pathology, 6th Edition

460 but blockage of left main coronary is a contraindication for 2. Internal mammary artery graft, however, has a patency
PCI. Unstable angioplasty may be associated with acute of more than 90% after 10 years.
coronary syndromes. PCI is followed by administration of 3. Atherosclerosis with superimposed complications may
anti-platelet (oral aspirin) and antithrombin therapy to avoid develop in native coronary artery distal to the grafted vessel
occurrence of coronary thrombosis. as well as in the grafted vessel.
Recurrent stenosis after metal stenting in PCI may occur
within 6 months in about 20% patients, more often in patients CARDIAC TRANSPLANTATION
of diabetes mellitus. Restenosis is multifactorial in etiology Since the first human-to-human cardiac transplant was
that includes smooth muscle cell proliferation, extracellular carried out successfully by South African surgeon Dr
matrix and local thrombosis. However, widespread use of Christian Barnard in 1967, cardiac transplantation and
drug-delivering stents has made it possible to overcome prolonged assisted circulation is being done in many
several long-term complications of coronary stening. countries in end-stage cardiac diseases, most often in
Currently, stents with anti-proliferative, anti-inflammatory, idiopathic dilated cardiomyopathy, heart failure and IHD.
cytotoxic and cytostatic agents are commercially available. Worldwide, about 3,000 cardiac transplants are performed
annually. The survival following heart transplants is reported
CORONARY ARTERY BYPASS GRAFTING as: 1 year in 85%, 5 years in 65% and 10 years in 45% cases.
Major complications are transplant rejection reaction,
Coronary artery bypass grafting (CABG) employs the use of infections (particularly with Toxoplasma gondii and
autologous grafts to replace or bypass the blocked coronary cytomegaloviruses), graft coronary atherosclerosis and
arteries. Most frequently used is autologous graft of higher incidence of malignancy due to long-term adminis-
saphenous vein which is reversed (due to valves in the vein) tration of immunosuppressive therapy. One of the main
and transplanted, or left internal mammary artery may be problems in cardiac transplant centres is the availability of
used being in the operative area of the heart. Long-term donors.
follow-up of CABG surgery has yielded following obser- The concept of cardiac stem cells resident in the heart
vations on pathology of grafted vessel: and possibly of bone marrow stem cells transdifferentiating
1. In a reversed saphenous vein graft, long-term luminal into cardiac myocyte has generated interest in treatment of
patency is 50% after 10 years. Pathologic changes which patients of IHD with transplantation of these stem cells.
develop in grafted vein include thrombosis in early stage, Preliminary studies in IHD cases have yielded encouraging
SECTION III
intimal thickening and graft atherosclerosis with or without results in clinical improvement and reduction in infarct size
complicated lesions. and hold promise for future.

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Systemic Pathology