In most centers wfiere this operation is routinely conducted the mortality is 1-2 per cent. In high-risk group of patients this inay go up to 5 to 10 per cent.
Long-term Follow-up Results
To cvaluate the long-tcrm results of surgeiy, one has to take into consideration the natural history, results of medical treatment and that of PTCA. The main factors to be considered are: (1) number of vcssels i~ffected and tlie site of obstruction, (2) LV fimction, (3) severity of reversible ischnemia, and (4) previous history of myocardial infarction. Coiltrol or risk facrors likc hypertension, diabetes, hyperlipidemia and obesity also plays important role, In the earlier years when only saphellous vein grafts were used, f ~ ~ r t h e r interventions were required in about 50 per cent of cases at the end of ten years.Currently rlon-usage of LIMA is taken to be a risk factol: Patients w l ~ o hnci total'merial revascularisation (TAR) have lesser symptoms, require less niuuber of rcintei-ventions, and have better life style and survival.
There are many studies comparing long-term results of' CABG Vs ITCA and stenting.
From this study it is obvious that survival is better and less iiunlber of reinterventions are required after surgery.
This can be compased with the results of medical treattnent done in thc earlier years of coronary artery surgery.
This is the Veterans administration co-operathe study (VACOOP study),which conclucted that in left main coronaq artery disease and triple vessel disease, surgery is definitely indicated because the results of medical treatment poor.
Recurrence of Angina
a) Early: Recurrence of angina soon after the patient resumes activities is either due to inadequate 1.evascula1isation or acute graft closure. I n the immcdiate post-operative period if ECG shows significant fresh changes or if there is unexplained hypotension acute graft occlusion has to be suspected. The best treatment is immediate re operation and re grafting for the occluded conduit. Very often, re grafting can be done off pump(OPCAB) or on cal-dio pulmonary bypass. Early recurrence of angina peaks asound 3'" month when patient has resumed normal activities. Coronary angiogram has to be done again and patient should have either angioplasty or repeal surgery depending on the findings.
b) Late recurrence of artgirza: This is a reflection of progress of disease in the native coronaiy arteiies distal to Lhe grafts or narrowing or blockage of one or inore of the grafts. This occurs more frequently when only saphenous vein grafts are used as conduits. Such patients should have angiogram followed by either angioplasty or surgery.
It has been nlcntioned earlier that usage of IMA to LAD is important for long-term survival and a life free of angina. A patent and functioning LIMA does 1101 prevent recull-ence of angina altogether as the ischaeinia could be in the territory of RCA or circumilex coronary artery. Coronary angiogram to show suitability for re grafting and thallium scan to show reversible iscllaemia in that tel~itory should be done before re intcrvenlion.
Re operation is a complicated procedure and carries higher risk as compared to primary surgery. The patients are older and may have co existing disease like diabetes. There is likelihood of progression of native coronary artery disease along with disease of conduits and probably poor LV function. At the time of surgery, athero-embolism fro111 partially patent vein grafts is a grave danger.There will be adhesion in the pericardium causing excessive bleeding. In case of patent LIMA to LAD, there is danger to that pedicle on release of adhesions. The h e a l may be dependant 011 this single graft.
The indications for re operation are generally the same as for primary operation.As the risk is highel; the operation should be reserved for illore symptomatic patients with large area of myocardium at risk. Patient should have at least one good target vessel of more than 1.5 mrn with more than 75 per cent proximal narowing before advising surgery. Thallium 201 myocardial perfusion scan will help in arriving at a decision in these patients.
The surgeon has to study carefully the previous operation notes and diagrams of coronary arteriography and the vessels grafted. A lateral view chest X-ray and CT scan will help in deciding on the relationship of R.V and aorta to the under surface of the sternum.
Technique
Careful re-opening of sternum and release of steinum from the underlying adhesion is done. Femoral artery and vein are exposed for going on femoro fenioral bypass, if there is torrential bleeding. Arterial conduits are prepared for re grafting. (IMA or RA) Availability of a cell saver is a good idea.Careful dissection to release the heart from pericardium is done. At times, last
part of the dissection can be done on bypass with an empty beating heart.Careful preservation of LIMA, which is functioning, and minimal handling ofrunctioning vein grafts is important. Good myocardial protection by antegrade and retrograde cardioplegia is i~nportant. The operation can also be done off pump (OPCAB).
Patients who have severe angina and dii'l'use coronalay artery discaye with no graftable vcssels are at limes sul>jected to TMLR. I n this proced~uc, txgct arcas of' niyocardiuru are miukcd based on pre-opcrutive studies. On a beating heart with special Inser cquipmenl, laser channels are creatcd one cln npa1.1 on selected arcas of niyocnrdium of left vcntriclc. 10-12. such channels arc created on the antel-ior anti lateral walls of LV as rccluired. These shoultl be away from major coronary ~u-tcry branches. At times there may bc one or two gr:il'tablc vesscls and large areas of myocaniia~n that cannot be lavescul;lsise~l. A hybrid procedure is done for thcse cases. TMLR is done first and after liacnlc~stasis patient is hepariniscd and gl-alting is done either on or off bypass. This procedure has been described ant1 popularisctl from Escorts Iios~~itul in Intlia by Dr. Nares11 Trchan.
Symptoinatic or asymptomatic carotid artery discasc may be present in patients undcrgoing CABG. It is very in~portant to recognize this pre-operatively, as haemodynnnlic fl~~ctuntion during CABG may result ill posl-operative stroke. i n the early years of CAB(;, more than GO per cent hloclt of carotid artcry, whether symptomatic or not was treated sul.gically belhrc CABG. If' piltient has bilateral lesion of more th:m (10 pcr cent, the clolninant side wils tackled first.
Long-term Follow-up Results
To cvaluate the long-tcrm results of surgeiy, one has to take into consideration the natural history, results of medical treatment and that of PTCA. The main factors to be considered are: (1) number of vcssels i~ffected and tlie site of obstruction, (2) LV fimction, (3) severity of reversible ischnemia, and (4) previous history of myocardial infarction. Coiltrol or risk facrors likc hypertension, diabetes, hyperlipidemia and obesity also plays important role, In the earlier years when only saphellous vein grafts were used, f ~ ~ r t h e r interventions were required in about 50 per cent of cases at the end of ten years.Currently rlon-usage of LIMA is taken to be a risk factol: Patients w l ~ o hnci total'merial revascularisation (TAR) have lesser symptoms, require less niuuber of rcintei-ventions, and have better life style and survival.
There are many studies comparing long-term results of' CABG Vs ITCA and stenting.
From this study it is obvious that survival is better and less iiunlber of reinterventions are required after surgery.
This can be compased with the results of medical treattnent done in thc earlier years of coronary artery surgery.
This is the Veterans administration co-operathe study (VACOOP study),which conclucted that in left main coronaq artery disease and triple vessel disease, surgery is definitely indicated because the results of medical treatment poor.
Recurrence of Angina
a) Early: Recurrence of angina soon after the patient resumes activities is either due to inadequate 1.evascula1isation or acute graft closure. I n the immcdiate post-operative period if ECG shows significant fresh changes or if there is unexplained hypotension acute graft occlusion has to be suspected. The best treatment is immediate re operation and re grafting for the occluded conduit. Very often, re grafting can be done off pump(OPCAB) or on cal-dio pulmonary bypass. Early recurrence of angina peaks asound 3'" month when patient has resumed normal activities. Coronary angiogram has to be done again and patient should have either angioplasty or repeal surgery depending on the findings.
b) Late recurrence of artgirza: This is a reflection of progress of disease in the native coronaiy arteiies distal to Lhe grafts or narrowing or blockage of one or inore of the grafts. This occurs more frequently when only saphenous vein grafts are used as conduits. Such patients should have angiogram followed by either angioplasty or surgery.
It has been nlcntioned earlier that usage of IMA to LAD is important for long-term survival and a life free of angina. A patent and functioning LIMA does 1101 prevent recull-ence of angina altogether as the ischaeinia could be in the territory of RCA or circumilex coronary artery. Coronary angiogram to show suitability for re grafting and thallium scan to show reversible iscllaemia in that tel~itory should be done before re intcrvenlion.
Re operation is a complicated procedure and carries higher risk as compared to primary surgery. The patients are older and may have co existing disease like diabetes. There is likelihood of progression of native coronary artery disease along with disease of conduits and probably poor LV function. At the time of surgery, athero-embolism fro111 partially patent vein grafts is a grave danger.There will be adhesion in the pericardium causing excessive bleeding. In case of patent LIMA to LAD, there is danger to that pedicle on release of adhesions. The h e a l may be dependant 011 this single graft.
The indications for re operation are generally the same as for primary operation.As the risk is highel; the operation should be reserved for illore symptomatic patients with large area of myocardium at risk. Patient should have at least one good target vessel of more than 1.5 mrn with more than 75 per cent proximal narowing before advising surgery. Thallium 201 myocardial perfusion scan will help in arriving at a decision in these patients.
The surgeon has to study carefully the previous operation notes and diagrams of coronary arteriography and the vessels grafted. A lateral view chest X-ray and CT scan will help in deciding on the relationship of R.V and aorta to the under surface of the sternum.
Technique
Careful re-opening of sternum and release of steinum from the underlying adhesion is done. Femoral artery and vein are exposed for going on femoro fenioral bypass, if there is torrential bleeding. Arterial conduits are prepared for re grafting. (IMA or RA) Availability of a cell saver is a good idea.Careful dissection to release the heart from pericardium is done. At times, last
part of the dissection can be done on bypass with an empty beating heart.Careful preservation of LIMA, which is functioning, and minimal handling ofrunctioning vein grafts is important. Good myocardial protection by antegrade and retrograde cardioplegia is i~nportant. The operation can also be done off pump (OPCAB).
Patients who have severe angina and dii'l'use coronalay artery discaye with no graftable vcssels are at limes sul>jected to TMLR. I n this proced~uc, txgct arcas of' niyocardiuru are miukcd based on pre-opcrutive studies. On a beating heart with special Inser cquipmenl, laser channels are creatcd one cln npa1.1 on selected arcas of niyocnrdium of left vcntriclc. 10-12. such channels arc created on the antel-ior anti lateral walls of LV as rccluired. These shoultl be away from major coronary ~u-tcry branches. At times there may bc one or two gr:il'tablc vesscls and large areas of myocaniia~n that cannot be lavescul;lsise~l. A hybrid procedure is done for thcse cases. TMLR is done first and after liacnlc~stasis patient is hepariniscd and gl-alting is done either on or off bypass. This procedure has been described ant1 popularisctl from Escorts Iios~~itul in Intlia by Dr. Nares11 Trchan.
Symptoinatic or asymptomatic carotid artery discasc may be present in patients undcrgoing CABG. It is very in~portant to recognize this pre-operatively, as haemodynnnlic fl~~ctuntion during CABG may result ill posl-operative stroke. i n the early years of CAB(;, more than GO per cent hloclt of carotid artcry, whether symptomatic or not was treated sul.gically belhrc CABG. If' piltient has bilateral lesion of more th:m (10 pcr cent, the clolninant side wils tackled first.
Simultaneoils CABG and CAE (carotid artesy cndustcrcctomy) had Iiiglicr rates of stroke and death. Carotid cndartcrectomy was done 2-5 days herorc CABG. Some surgeons fi~vour this. However if rlle comary artery discasc is critical, it is better to do both siniulla~~cously.Now even il' the cardiac status is stablc many surgeons advise one s l a g operation. With a single aliaesthchia and hospitalisation, this approach is probably better.hi a combined proceduse, the hear1 is exposed and co~iduits harvested at thc same Lime carotid arlcry is exposed. Thc common carotid artery, bir~~rcation, external and internnl carotid arteries are exposed. The internal.carotid aslery is exposed well above the diseased part. The vessels are looped. The external carotid, distal ends of internal carotid and common carotid are clamped. A vertical incision on the biCul.cation exterldi~lg on Lo the internal carotid is made. If back bleeding is not satisfactory on removal of distal internal carotid clamp, an intra luminal shunt has to be placed to protect cerebral circulation.
Endarterectomy is done from internal and common carotid arteries. Loose fragments are removed and irrigated well. At times the intinla has to be fixed with 7'01prolene suture inside the internal carotid artery. A~leriotomy is closcd with a vein patch or synthetic Goretex patch so as not to narrow the artery.The wound is packed and closure is clone after CABG and reversal of heparin with protamine. The peri-operative stroke and mortality rate
Endarterectomy is done from internal and common carotid arteries. Loose fragments are removed and irrigated well. At times the intinla has to be fixed with 7'01prolene suture inside the internal carotid artery. A~leriotomy is closcd with a vein patch or synthetic Goretex patch so as not to narrow the artery.The wound is packed and closure is clone after CABG and reversal of heparin with protamine. The peri-operative stroke and mortality rate
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.