CABG in diabetics: surgical aspects Dr Raja Parvaiz Akhter Head of Cardiac Surgery Department, PIC, Lahore.

Diabetic patients have a particularly high risk of cardiovascular mortality Diabetes alone is a major risk factor Diabetics may suffer from accelerated atherosclerosis and a high proportion demonstrates an extensive form of CAD Diffuse peripheral involvement of the coronary circulation.

Patients suffering from diabetes have a higher mortality rate following myocardial infarction than those without diabetes Reasons for this may be multiple: Changes in the vascular endothelium under elevated blood glucose induce an impairment of the endothelium dependent vasodilatation Due to a reduction of the synthesis or release of nitric oxide

Accelerated inactivation of nitric oxide by high levels of free radicals Release of potent vasoconstrictors Increased activation of protein kinase C Decrease expression of inhibitory proteins causing abnormalities in signal transduction Reduced coronary flow reserve in diabetics and the diminished microvascular dilatation Poorer development of collateral vessels in the coronary circulation of diabetic patients

Lifetime Risk of Coronary Artery Disease Lifetime Risk of CAD Without Diabetes CAD 5.4% No CAD 93.8% Lifetime Risk of CAD with Diabetes No CAD 46% CAD 54 % Furnary, “Portland Continuous Intravenous Insulin Protocol: Laboratory Considerations,”

Diabetic Cardiac Surgery Population Percentage of U.S. Population Without Diabetes Mellitus Non-DM 94% DM 6% Percentage of Cardiac Surgery Population With Diabetes Mellitus Non-DM 71% DM 29% Furnary, “Portland Continuous Intravenous Insulin Protocol: Laboratory Considerations,”

Revascularization in Diabetics CABG and PTCA do poorly in diabetics CABG or PTCA do not cure diabetes nor CAD

Diabetes mellitus, a major determinant of cardiovascular events, portends an adverse prognosis in patients with coronary artery disease regardless of treatment strategy.

Within the global CABG population, diabetic patients demonstrated the following particular characteristics: They are older The proportion of females is higher Coronary circulation is more severely involved Higher number of stenosis Higher rate of prior myocardial infarction Higher incidence of decreased left ventricular contractility and Their overall cardiovascular risk profile is significantly worse than in non-diabetic patients

Specific vascular biology in diabetes DM have smaller vessels Less plaque mass but greater neg. remodelling Endothelial dysfunction Altered platelet function and coagulation DM have more plaque ruptures and different plaque morphology

Patients with diabetes comprise 15 to 29% of surgical population Associated with: Longer stay Greater infection rate Higher operative mortality Worse long-term prognosis

Specially true for patients with In diabetic patients CABG using arterial conduits should be the preferred. Specially true for patients with Left main involvement, Coronary three vessel disease with reduced LV-function and Diffuse coronary involvement

Several studies demonstrate increased perioperative morbidity among diabetics, including Neurologic Complications, Renal dysfunction Sternal wound infection

PTCA vs. CABG ARTS, arterial revascularisation therapy study BARI, bypass angioplasty revascularisation investigation CARDia, coronary artery revascularisation in diabetes EAST, Emory angioplasty versus surgery trial RITA, randomised intervention treatment of angina SoS, stent or surgery

ARTS I MACCE (30 day follow-up) CABG (605) Stent (600) Death 8+3* 1.8% 9 1.5% CVA 7+1 * 1.3% 5 0.8% AMI (Q) 13+4* 2.8% 15+1* 2.7% Re-CABG 2 0.3% 12 2.0% Re-PTCA 3 0.5% 10 1.7% Total 41 6.8% 52 8.7% *Events prior to assigned treatment

ARTS Trial (CABG v. PCI) Three year Follow-up 100 90 80 70 CABG 60 50 95.7% 87.8% 85.0% 83.6% 91.8% CABG Event Free Survival (%) 73.5% 69.5% 65.7% PCI p=0.005 Log Rank p=0.006 Fisher Death AMI CVA CABG Re-PCI 0 150 300 450 600 750 900 1050 1200 Days since randomization

Three year Follow-up (Diabetic subgroup) ARTS Trial (CABG v. PCI) Three year Follow-up (Diabetic subgroup) 100 90 80 70 60 50 CABG 92.7% Death, AMI, CVA PCI = CABG Event Free Survival (%) 61.6% PCI p=0.0001 Log Rank p<0.0001 Fisher CABG Re-PCI 0 150 300 450 600 750 900 1050 1200 Days since randomization

BARI

Total No of Patients 795 Total Grafts 2309 Off - Pump VS On – Pump CABG Prospective Randomized Comparative Study From Jan. 2006 to March 2007 at PIC, Lahore Total No of Patients 795 Male 682 (85.5 %) Female 113 (14.2 %) On-Pump 328 ( 41.3 %) Off-Pump 467 (58.7 %) Total Grafts 2309 Coronary Endarterectomy patients 126 (15.8 %)

Diabetics Non diabetic 2 (1.0) 1 (0.3) 0.282 22 (11.2) 33 (10) 0.643 Off - Pump VS On – Pump CABG Prospective Randomized Comparative Study Complications in Diabetic CABG patients Complications Yes (%) N= 242 No (%) N = 331 p-value Diabetics Non diabetic Neurological 2 (1.0) 1 (0.3) 0.282 Arrhythmias 22 (11.2) 33 (10) 0.643 Respiratory 19 (8.8) 29 (8.76) 0.986 Wound Infection 9 (3.7) 7 (2.1) 0.249 AMI 15 (6.19) 15 (4.53) 0.378 Low cardiac Output 6 (2.47) 0.019* IABP 12 (4.95) 5 (1.5) 0.016* Renal Failure 36 (14.87) 22 (6.64) 0.001* Mortality 15 (6.2) 6 (1.8) 0.005* Re-opening 5 (2.06) 0.612 Other complications 0.402

Low out put syndrome Diabetics VS Non- diabetics

Post CABG use of IABP Diabetics VS Non- diabetics

Post CABG Mortality Diabetics VS Non- diabetics

Our study – Complications in Diabetic patients

Recommendation An aggressive secondary prophylaxis which is directed to correct all cardiovascular risk factors is recommended in all patients, especially in diabetics. There are no difference to make in recommendations for long-term follow-up after PCI or CABG surgery.

Conclusions Percutaneous treatment of diabetes associated coronary artery disease seems to remain challenging, despite advances in the stent technology and anti-thrombotic treatment Acute results of PCI are comparable to those obtained in non-diabetic patients, the longterm results are in the majority of trials still Worse There is great hope among cardiologists, that systematic use of clopidogrel, preloading, drug-eluted stents and treatment with GPIIb/IIIa inhibitors will improve the results This may be partially true in the future, but nevertheless, all these strategies will never compete with exclusive arterial surgical revascularisation techniques with or without cardiopulmonary bypass