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Cardiac Surgery and Sickle Cell Disease Khaled E. Al-Ebrahim FRCSC Department of surgery,Faculty of Medicine King AbdulAziz University,Jeddah,Saudi Arabia Please send correspondence to Dr khaled Al _Ebrahim ,department of surgery, king abdulaziz university hospital ,p o box 80215 Jeddah 21589 [email protected] TEL 02-6401000 FAX 02-6408347 ABSTRACT Three cases of homozygous sickle cell disease underwent successful open heart surgery for multivalvular lesions. The description of the surgical technique and the necessary precautions are described. Exchange transfusion was implemented in all cases. We reviewed the world literature and analysed specific crucial issues in cardiac surgical management of those chronically and critically ill patients to avoid or at least minimize the vaso-occlusive crisis and associated complications. Key words : sickle cell, cardiac surgery ,valve procedure. Introduction Sickle cell disease is one of the commonest genetic disorder world_wide and affecting about 8% of black people[1] .The prevalence in Saudi Arabia in not studied. Sickle cell anemia is an inherited disease in which the red blood cells, normally discshaped, become crescent shaped causing small blood clots which give rise to recurrent painful episodes called "sickle cell pain or vaso- occlusive crises".Complications of sickle cell disease include recurrent aplastic and hemolytic anemia , gallstones ,multisystem disease (kidney, liver, lung (,narcotic abuse ,splenic sequestration syndrome , acute chest syndrome ,erectile dysfunction (as a result of priapis) , blindness/visual impairment , neurologic symptoms and stroke , joint destruction , infection, including pneumonia, cholecystitis , osteomyelitis , and urinary tract [2,3]. As surgery in general and especially cardiac surgery in homozygous patients is associated with high morbidity and mortality, special care and certain precautions are required peri-operatively in their management to minimize the surgical risk. Patients and Methods Three patients with sickle cell disease underwent open heart surgery for multivalvular lesions .The deails are as follows. CASE #1 18 years old chadian male patient known case of sickle cell disease(80% sickling by hemoglobin electropheresis) ,renal impairment and rheumatic heart disease was admitted with abdominal pain, dyspnoea, recurrent fever and chills.On examination his temperature was 38.5, heart rate 110,normal sinus rhythm , blood pressure 100/60.Auscultation revealed visible laterally displaced apex beat ,pansystolic mitral murmer and early diastolic aortic murmer. His Hemoglobin was 7.5 g/dl, white cell count was 19 000k/uL , urea 34mmol,creatinin 369umol ,total bilirubin was 130umol ,indirect bilirubin 90umol. He was admitted to the intensive care unit where ecchocardiography showed dilated cardiac chambers ,severe mitral and aortic regurgitatin , moderate pulmonary regurgitation and pulmonary hpertension..Ejection fraction was only 30%. Blood cultures were sent and the patient started on empiric antibiotics ,ceftriaxon , erythromicine and ampicillin . The following day, the patient developed convulsions and he was intubated and mechanically ventilated . Computerised tomography scan of the brain was showed suspicious hypodensity in the right periventriculer white matter region. The patient improved gradually and extubated . The cultures grew staphylococcus epidermidis (coagulase negative) and he received six weeks of intravenous antibiotics. He was discharged and readmitted for valve replacement . Cardias Surgery was done where metallic aortic and mitral valves (ATS MEDICAL ) were inserted . All Perioperative sickle cell precautions were undertaken . Postoperative course was smooth .The patient was started on anticoagulation ,mobilized and discharged home well. Case #2 : 28 years old male patient ,originally from south Saudi Arabia, known case of sickle cell disease , rheumatic heart disease, severe mitral and aortic regurgitation. He was admitted for recurrent attack of shortness of breath on moderate exertion . Cardiac examination revealed muffeled first heart sound , normal second heart sound , pansystolic murmer over the apex radiating to the axilla and early diastolic murmer over aortic area . No lower limb edema . His hemoglobin was 7.5gram% . Urea and electrolyte were normal. Elctrocardiogram showed normal sinus rhythm, left ventricular dilatation. Ecchocardiography revealed severe aortic insufficiency , moderate to severe mitral insufficiency , left ventricular dysfunction , moderate to severe pulmonary hypertention , ejection fraction 60%. The patient underwent aortic and mitral valve replacement using St Jude Medical Biocor valves (aortic valve size 21 and mitral valve size 27). The patient had smooth intra and postoperative course .Cardiac rehabilitation and temporary anticoagulation were started. Postoperative ecchocrdiography showed status post mitral and aortic valve replacement ,both valves were functioning well, no paravalvuler leak or dihescence with mild to moderate left ventricular dysfunction , ejection fraction 50%.Patient was discharged home in good condition with clinic followup. He has been followed for more than one year with steady improvement. Case #3 14 years old Sudanese female patient known case of sickle cell disease (more than 80%by electrohemopharesis ), rheumatic heart disease mainly severe mitral and tricuspid regurgitation , pulmonary HTN , old treated TB. She presented to the emergency room with bilateral lower limb edema for 3 day associated with shortness of breath at rest and orthopnea . On examination, the patient was jaundiced , multiple cervical lymph nodes, her jugular venous pressure was 7-8 cm , hyperdynamic circulation,regular pulse, normal first heart sound , loud secod heart sound , pansystolic murmer at mitral and tricuspid area, Abdominal examination revealed hepatomegaly and ascitis. She had also bilateral lower limb edema . She was started on diuretics and digoxin . During hospitalization she went into fast atrial fibrillation which was controlled with amiodaron . The patient underwent mitral and aortic valve repair using annuloplasty flexable rings(size 30 for the mitral and 32 for the tricuspid) . Postoperative course was smooth and eventually she was discharged home in good condition . METHODS: General anesthesia was induced using ethomidate, fentanyl, midazolam and pancuronium and was maintained oxide.Cardiopulmonary bypass was using isoflurane ,oxygen and nitrous constructed using membrane oxygenator, cardiotomy reservoir , regular and haemofilters, and tubing set .The circuit was primed using ringers lactate ,5% dextrose ,8.4% sodium bicarbonate and 1 unit of blood. Heparinisation was achieved by 300 units/kg. Normothermic bypass was coducted using aortic and bicaval cannulae and cardiac arrest was achieved with hypothermic blood cardioplegia. All patients underwent about 30%exchange transfusion and continuous haemofiltration during cardiopulmonary bypass. The haemoglobin was maintained between 6-8.5 g/dl with a hematochrit between 18-28%.Th mitral valve was approached through the interatrial groove.All three patients had different valve procedure. The first case received two mechanical valves using ATS MEDICAL,hoping for its proven low thrombogenicity, as both valves were destroyed by the endocarditis process and to avoid hypercalcification of bioprosthetic valves which is usually associated with renal failure patients .The second patient received two tissue valves to avoid the controversial issue of prosthetic valve associated hemolysis [6]. In the third patient ,fortunately both mitral and aortic valves were repaired using annuloplasty rings. All three patients were weaned off cardiopulmonary bypass without difficulty . Discussion Sickle cell anemia affects millions throughout the world. It is particularly common among people whose ancestors come from sub-Saharan Africa; South America, Cuba, Central America, Saudi Arabia; India; Turkey, Greece, and Italy. Hemoglobin (HbS) results from single base mutation in beta chain of haemoglobin , adenine base replaced by thymine so glutamic acid is replaced by valine. Sickling test and hemoglobin electrophoresis help in diagnosis and differentiates individuals who are homozygous from those who are heterozygous. A homozygous patient will have hemoglobin SS (HbSS, 80-90%), hemoglobin F (HbF, 2-20%), and hemoglobin A2 (HbA2, 2-4%). A carrier patient will have HbSS (35-40%) and hemoglobin A (HbA, 6065%). The test is not accurate in a patient who has recently received blood transfusions[3]. Clinically, common symptoms include paleness, yelloweyes/skin, fatigue, breathlessness , rapid heart rate ,delayed growth and puberty . Sickling may be induced by hypoxia ,hypothermia ,cidosis ,vascular stasis or hypovolemia. The purpose of therapy is to manage and control symptoms and to try to limit the frequency of vaso-occlusive crises. During a sickle crisis, certain therapies may be necessary. Painful episodes are treated with analgesics and adequate liquid intake. Hydroxyurea (Hydrea) was found to help some patients by reducing the frequency of painful crises and episodes of acute chest syndrome and decreasing the need for blood transfusions. Antibiotics and vaccines are given to prevent bacterial infections, which are common in those children. The risk of an intraoperatively crisis due to sickle cell disease is a major consideration in cardiovascular surgery. It is will documented in the medical literature that low oxygen tension and acidosis can induce sickling in the red cell and in those patients the cardiopulmonary bypass, as an artificial circulation wholly controlled by the perfusionist , may trigger a crisis of profound magnitude . As regard to cardiopulmonary bypass several precautions and issues have to be addressed and analyzed . These included cardiopulmonary bypass temperature, whether to cool or warm, also cardioplegia temperature , the need for partial exchange transfusion and continuous haemofiltration. It is generally worldwide agreed that avoidance of acidosis , maintenance of cardiopulmonary bypass adequate blood flow ,oxygen tension and close monitoring of laboratory results are essential basics in the management of sickle patients[4-7]. These issues have to be very well understood by the perfusionist , anaesthesiologist and the surgical team as violation may increase the surgical risk and jeoperdise patient life. Contiuous on line arterial oxygen tension , acid base balance and temperature are essential. Intra and postoperative control of the haemodynamics, regular follow up of haematocrit , keeping it between 20 and 30%, electrolytes , blood gases, avoidance or minimizing postoperative pain are important in those patients Although ,it is preferable to avoid hypothermia which will cause vasoconstriction in those patients ,still a number of studies, case reports, have employed mild to moderate cooling without adverse effect[7,8]. Reviewing the literature and from our cases we found that normothermic bypass , allowing the temperature to drift and using only cold cardioplegia, at four degrees centigrade, is the safest especially when operating on high risk and large number of cases[4-6,9,10,14,15]. Warm blood cardioplegia ,with its high potassium , may have deleterious effect on patients with impaired renal function Pre or intraoperative partial exchange transfusion have been recommended by many authors and implemented in the majority of cardiac patients to reduce the percentage of Hb SS[6,7,9,10] . At least 30 % of the circulating plasma volume is sequestered to improve the quality of the perfusate, increase oxygen delivery and to decrease the risk of a sickle cell crisis during bypass . In few case reports ,exchange transfusion was not implemented [5,8]. In the series of Metras et al.,most of the cases ,13 patients, were sickle cell trait . In our cases , exchange transfusion was done once intra operatively ,after cannulating and before going on bypass . The perfusionist drains about 500 to 1000ml of blood from the venous reservoir ,depending on the patient body weight , and replaced with 1 to 2 units of packed red blood cells . Hemofiltration will increase hematocrit, platelets and clotting factors, help potassium removal, reduce complement activation, reduce extracellular water and help in avoiding acidosis. Several papers showed the favorable but sometimes variable effect of haemofiltration especially in the pediatric patients[6,7,11-13]. Valve repair remains the procedure of choice to avoid prosthetic valve related complications especially hemolysis,anti-coagulation and infection[5-8,14]. In our review of the literature , several authors did not show any preference of tissue valves over mechanical valves[4,5,7,8,15]. Others showed that mechanical valves should be avoided in sicklers to minimize the risk of hemolysis which may induce crisis[6]. In our cases ,we used three different valve procedures . Given the short life expectancy of those patients , the risk of mechanical valve hemolysis , tissue valve hypercalcification and risk of reoperation , we prefer , in nonrepairable valves, use of mechanical valves for patients less than 30 years and elder patients may receive biological valves. Postoperative pain management is helped by receiving multiple analgesia. Prophylactic antibiotic therapy is important in those patients to minimize the risk of infection. These three cases performed by the author received different valve procedures which emphesises the tolerance of those patients as long as the body environment during and after surgery are suitable and not triggering vasospasm . Four previous other sickle cell trait patients underwent also valvular procedures by the author in another institution and did not face any problems as those trait cases are not as critical as the homozygous. The world literature is deficient and has no major scientific contribution to help this sector of cardiac patients , except of sporadic case reports , most of it more than a decade ago. References [1] Heller P, Best WR, Nelson RB, Becktel J. Clinical implication of sickle cell trait and G6PD in hospitalized black male patients. N Engl J Med 1979;300:1001-5. [2] Ned JV.Sickle cell disease :a worldwide problem. In Abrahamson H, Bertles JF, Wether DL, eds. Sickle Cell Disease: diagnosis, management, education and research.St Louis:Mosby1973. [3] WintrobeMM. Clinical hematology,Philadelphia:Lea&Febiger,1993:1064. [4] Wenham PW, Scott GI, Wisheart JD. Red blood cell survival after aortic valve replacement with Bjork-Shiley prosthesis in presence of sickle cell trait. Br Heart J 1978;40:703-4. [5] Metras P, Chauvet J. Open heart surgery in sickle cell haemoglobinopathy;report of 15 cases. Thorax 1982;37:486-91. [6] Balasundaram S,Duran CG,Al-halees Z,Kassay M.Cardiopulmonary bypass in sickle cell anemia ,Report of five cases.JCardiovascSurg(Torino)1991;32:271-40 [7] Sutton SW,Hunley EK,Duncan MA,RodreguesR,Meyers T. Sickle Cell Disease and Aortic Valve Replacement. Texas Heart Inst J 1999;26:283-8. [8]Frimbong-Boateng K , Amoah AGB, Barwasser H-M, Kallen C. Cardiopulmonary bypass in sickle cell anaemia without exchange transfusion. European Journal of Cardio-Thoracic Surgery1998;14(5):527-9. [9] Black HA, Dearing JP. Exchange transfusion prior to cardiopulmonary bypass in sickle cell anemia. J Extra-corp Technol 1980;12:82-5. [10] Chun PKC, Flannery EP, Bowen TE. Open heart surgery in patients with hematologic disorders. Am Heart J 1983;105:835-42. [11] Hata M,Raman JS, Bellomo R, BuxtonBF, ShionoM, Sezai Y.Hemofiltration during cardiopulmonary bypass for high risk adult cardiac surgery. Science Links Japan 2002;44:53-60. [12] Brancaccio G, Villa E, Girolami E. Inflammatory cytokines in pediatric surgery and variable effect of the hemifiltration process.Perfusion2005;22:263-8. [13] Sexana P, SexanaN, Sharma R. Efficacy of haemofiltration during cardiopulmonary bypass in pediatric open heart surgery.2001;17(2):73-6. [14] Pagani FD, Polito RJ, Bolling SF. Mitral valve reconstruction in sickle cell disease .Ann Thorac Surg 1996;61:1841-3. [15] Craenen J, Kilman J, Hosier DM, Weinberger M. Mitral valve replacement in a child with sickle cell anemia. J Thorac Cardiovasc Surg 1972;63:797-9. Date 12 June 2008 Dr. khaled Al _Ebrahim To Tracking No. OC 80092 [Please quote this tracking # on all your correspondence] Cardiac Surgery and Sickle Cell Disease Title The comments raised by reviewers must be addressed in the revised manuscript Disagree (must give Summary Agree reasons) Problems during cardiopulmonary bypass yes Technique of exchange transfusion yes Cardioplegia temperature , yes 1 3 4 PLEASE NOTE: REVISION SUBMISSION WITHOUT RETURNING THIS FORM WILL NOT BE PROCESSED Reasons for Disagreement: