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CORONARY ARTERY BYPASS. Paul J. Corso, M.D., FACS, FACC Chief Cardiovascular Surgery, Washington Hospital Center. Coronary Revascularization - Surgical. Historical Review: 1946 Vineberg IMA implant into cardiac muscle 1954 Murray Experimental anastomosis (IMA/SVG)
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CORONARY ARTERY BYPASS Paul J. Corso, M.D., FACS, FACC Chief Cardiovascular Surgery, Washington Hospital Center
Coronary Revascularization - Surgical • Historical Review: • 1946 Vineberg IMA implant into cardiac muscle • 1954 Murray Experimental anastomosis (IMA/SVG) • 1962 Sabiston First CABG (SVG to RCA) • 1964 Garrett First CABG to LAD without pump • 1967 Kolessov Lima-LAD, thoracotomy • 1968 Favaloro Initial experience with SVG with pump • 1970 Johnson Expanded experience CABG • 1972 Ankeney USA 1st Single graft series w/o CPB
Classic Procedure (Same Operation For All) Sternotomy IMA Harvest SVG Cannulation for CP Bypass Arrest Heart Anastomosis Heparin Wean From Bypass Reverse heparin and Stop Bleeding
21st Century CABG On pump with sternotomy Off pump with sternotomy Small incisions on pump Small incisions off pump
CORONARY ARTERY BYPASS GRAFTING WITHOUT CARDIOPULMONARY BYPASS Complications of cannulation/clamping Bleeding – aorta and atrium Dissection Embolization
CORONARY ARTERY BYPASS GRAFTING WITHOUT CARDIOPULMONARY BYPASS Consumption of coagulation factors Platelet damage Bleeding Leukocyte damage (pyrogen) Fever Leukocyte & platelet-mediated endothelial damage Edema (increased Complement-induced increased interstitial H2O) vascular permeability Bradykinin Vasoconstriction Platelet & fibrin microemboli Organ dysfunction
CPB – Causes of Neurological Abnormalities • Platelet micro-emboli • Air emboli • Atherosclerotic emboli • Aortic cross clamping • Aortic cannulation • Proximal graft placement
COMPLICATIONS OF CABG Death MI CVA Infection Bleeding 70% Related to use of CP Bypass
Bleeding is a Significant Aspect of CABG 300,000 Operations 46% received blood and/or blood products 2.5% returned to OR for bleeding SOURCE – STS Database
Complications of Blood Transfusion • Death! – “With non-leukocyte reduced transfusions in randomized trials, multiorgan failure and death may occur in up to 10% of transfused intensive care unit patients versus 5% in recipients of leukocyte reduced blood transfusions” => at least 5% of patients may die as a result of blood transfusions!!! • Leukocyte-related target organ injury in 2 to 5% • Transfusion-related acute lung injury (TRALI) may be the most common complication!!
Intraoperative RBC Tx Increases Risk of Low Output Failure • 8004 Patients, Northern New England Cardiovascular Disease Study Group • Included only patients with <=3 units RBCs • nadir hematocrit associated with LOF (p<.02) • RBC TX also INDEPENDENTLY associated with LOF (p=0.047)!! Surgenor, et al. Circulation 2006;114:43-48
Adverse outcomes of Blood transfusion after cardiac surgeryVamvakas et al Transfusion 2000 • Prolonged need for mechanical ventilation Habib et al Ann thorac surg 1996 • Impaired wound healing Chmell et al J surg onc 1996 • Multiple organ system failure Tran et al Nephro Trans 1994 • Prolonged length of stay in hospital Vamvakas et al Trans 2000 • Increased postoperative mortality Watering et al Circ 1998
Transfusion in CABG is associated with Reduced long term SurvivalBlackstone et al Ann Thorac Surg 2006 Cleveland Clinic • 10,289 patients from 1995 to 2002 • Blood transfusion rate of 49%, Platelets in 9 %,FFP in 2.5 % and Cryo in 0.5 % • Risk adjusted: Increased early hazard at 6 months (p< 0.0001) and late hazard at 10 years ( p<0.0001) • Decreased survival is “dose dependant” i.e. no. of units • Unadjusted risk: 5-year survival in non-transfused vs. transfused was 80 % and 63 %
Outcomes: Blood Transfusion Landmark observational study – 10,289 isolated CABG patients Transfusion in coronary artery bypass grafting is associated with reduced long-term survival. Colleen Gorman Koch, Liang Li, Andra I Duncan, Tomislav Mihaljevic, Floyd D Loop, Norman J Starr, Eugene H Blackstone. Ann Throac Surg 2006;81(5):1650-7.
Outcomes: Blood Transfusion First large-scale study (10,949 patients) to closely examine isolated CABG surgery related transfusions and outcomes Each unit of packed red blood cells transfused was associated with an increased risk of: Morbidity and mortality risk associated with red cell and blood-component transfusion in isolated coronary artery bypass grafting. Colleen Koch, Liang Li, Andra Duncan, Tomislav Mihaljevic, Delos Cosgrove, Floyd Loop, Norman Starr, Eugene Blackstone. Crit Care Med 2006;34(6):1-9.
Predictors of Postoperative Bleeding – The Big 6 • Advanced age • Small body size or preoperative anemia (low RBC volume) • Anti-platelet & anti-thrombotic drugs. • Prolonged operation (CPB time) – high correlation with OR type. • Emergency operation • Other co-morbidities (CHF, COPD, HTN, PVD, renal failure, etc.) Ferraris VA, et al. STS Guidelines. Ann Thorac Surg. 2005;79:1454-61.; Ferraris VA, et al. Ann Surg. 2002;235:820-7.
Does Aspirin Cause Increased Postoperative Bleeding • 21 studies reviewed the effect of aspirin on postoperative bleeding. • 5 of 6 randomized trials showed increased bleeding due to aspirin (Level A evidence). • Evidence less convincing in 15 observational studies (Level B or C evidence). Ferraris VA, et al. STS Guidelines. Ann Thorac Surg. 2005;79:1454-61.
Postoperative Bleeding and Aspirin • Can estimate the amount of bleeding after operation due to aspirin • 200-400cc of increased chest tube blood loss • 0.5 to 1.0 unit of blood transfusion due to aspirin. • Lower doses of aspirin protect just as well and are associated with less bleeding. Ferraris VA, et al. STS Guidelines. Ann Thorac Surg. 2005;79:1454-61.
Blood Conservation Interventions – Class I Recommendations: “Is Recommended” • Identify high risk preoperatively. • High dose aprotinin; Low-dose aprotinin • Lysine Analogs • Cell saver • Blood transfusion algorithm w/ point-of-care testing. • Multimodality approach. Ferraris VA, et al. STS Guidelines on blood conservation. Ann Thorac Surg, May 2007;83:S27-89
Blood Conservation - Class IIA Recommendations: “Is Reasonable” • Preoperative Epogen • Intervention in Patients with thrombocytopenia • Autologous predonation • Off pump Bypass • Alternatives to Blood sampling • Total Quality Management • Discontinue plavix 5 to 7 days preop • RBC Transfusion for Hemoglobin < 6: Higher trigger in elderly, CVA, cardiac dysfunction, ischemia • Blood component transfusion for clinical bleeding Ferraris VA, et al. STS Guidelines on blood conservation. Ann Thorac Surg, May 2007;83:S27-89
Mangano & co-workers Conclusion • ‘Association between aprotinin & serious end-organ damage indicates that continued use is not prudent. In contrast, the less expensive generic medications, EACA & TXA, are safe alternatives.’ Mangano, 2006, NEJM
Aprotinin – Workforce on Evidence Based Surgery Response NEJM • ‘…data mostly representing level A evidence suggests that high-dose aprotinin has an acceptable risk-benefit profile and is indicated for blood conservation (class I, level A) in patients at increased risk for bleeding.’ Ferraris, Bridges and Anderson, 2006, NEJM
Evidence-Based Blood Conservation Strategies: Pennsylvania Hospital • Top 4 • Preoperative interventions • Epogen: Hgb =16 ideally • Limit anti-thrombotic & anti-platelet drug effect. • Limit blood loss during operation • High-dose aprotinin or anti-fibrinolytics • Meticulous hemostasis • Speed of operation • Perfusion strategies (minipump) • Salvage & sequester blood (not as helpful in high-risk) • Cell saver, pump salvage, RAP, AAP, etc. • Normovolemic Hemodilution (predonation) • Manage blood resources (process of care variables) • Multimodality approach including postop epogen/iron • Transfusion algorithm & point-of-care testing.
PAH Cardiac Surgery Blood Conservation ProtocolPre Operative measures • Consult Bloodless Medicine Team for all patients • Outpatients seen by Bloodless Medicine on the same day of Cardiac visit • Erythropoetin administration: • 40,000 U SQ weekly (caution in renal failure, cancer) • In selected cases, acute Coronary syndromes may be stabilized with stenting culprit vessel and elective CABG/Hybrid approach Courtesy of Dr. Bridges
PAH Cardiac Surgery Blood Conservation protocolPre operative measures • Avoid daily labs in the Inpatients awaiting surgery • Serum Ferritin levels in all patients • Bloodless Medicine will decide the need for Ferrlecit 125 mg IV/day 3 times • Angio - Seal recommended for all patients who may need surgery in the next 48 hrs ( blood loss upto 1 to 2 gms Hb from cath site reported) • Vitamin K 10 mg oral for selected patients pre operatively Courtesy of Dr. Bridges
PAH Cardiac Surgery Blood Conservation protocolManage risk factors for transfusion • Coumadin – normalize INR preoperatively; convert to Lovenox as needed • Stop Lovenox 24-48 hrs prior to surgery • Aspirin (low risk patients/Jehovah’s witnesses), Plavix to discontinue for 5 to 7 days • Celebrex • Ginka and other herbal supplements • Garlic, Vitamin E, Saw Palmeto • No Alcohol for at least 1 week • Pre operative anemia – major risk factor for transfusion Courtesy of Dr. Bridges
PAH Cardiac Surgery Blood Conservation ProtocolIntra operative measures • Trasylol ( Aprotinin) to be used in high risk patients ex: Plavix, combined procedures, aortic surgery, JW • Auto donation: ( Normovolemic hemodilution) Red cell volume > 900 - 1 unit Red cell volume > 1100- 2 units Red cell volume > 1400- 3 units “One sponge technique” • Blood returned to the patient after cardiopulmonary pass • Fibrillatory arrest for redo AVR patients with patent IMA Courtesy of Dr. Bridges
PAH Cardiac Surgery Blood Conservation ProtocolIntra Op measures- Bypass circuit • Miniature Cardiopulmonary Bypass Circuits • CELL SAVER ONLY • Leg elevation, chair position improves venous drainage • Antegrade and Retrograde priming • Smaller venous line 3/8 as opposed to ½ - less prime • ‘Follow through’–retrieve all blood from bypass circuit • Full rewarming to 36 deg before weaning bypass Courtesy of Dr. Bridges
Best Strategy: Optimize Cardiopulmonary Bypass Technology • 1. Reduces systemic inflammatory • response syndrome and preserves platelet function. Aprotinin enhances this effect • Decreases Blood Loss • Avoids Reduced Graft Patency of Off Pump Bypass • Applicable to all situations
Low Prime Circuits: Benefits • Reduced Priming Volume • Reduced hemodilution • Decreased blood component usage • Reduced foreign surface area • Less contact activation (systemic inflammatory response)
Summary – Low Prime Circuits • Demonstrated safety and efficiency • Proven results regarding clinical factors that influence patient outcomes (nadir HCT/Frequency of blood transfusions) • Confirmed cost avoidance • Low impact to surgical technique • Procedure independent – can by utilized on all procedures requiring CPB
PAH Cardiac Surgery Blood conservation ProtocolIntra Op measures–Hemostatic agents • Thrombin, Gelfoam, Surgicel for sternum • Bio Glue and Fibrin glue ( ex Tissel) as needed • ‘Point Of Care Testing’ to be evaluated Courtesy of Dr. Bridges
PAH Blood Conservation ProgramPost op measures – bleeding patients • Coagulation profile- Protamine as needed • Correct temperature • Replace volume with 5% Albumin • Positive Airway Pressure • Cryoprecipitate • Early re exploration Courtesy of Dr. Bridges
PAH Cardiac Surgery Blood Conservation ProtocolPost op measures – Minimize labs • Avoid routine labs • Use peripheral lines • Small “pediatric” tubes • Stable patients – labs on alternate days Courtesy of Dr. Bridges
Conclusions • A multimodality approach to blood conservation is essential • Guidelines are useful to help guide therapy and reduce variability in practice. • Aprotinin is an important adjunct to a comprehensive cardiac surgery blood conservation program in high risk patients, Jehovah’s witnesses, and other “transfusion free” cardiac surgery patients • The avoidance of blood transfusion in cardiac surgery patients decreases costs, morbidity and is likely to decrease mortality as well.