BACKGROUND: Thromboxane A2 and endothelin-1 are the potent vasoconstrictors affecting pulmonary pathophysiology in response to whole body inflammatin following CPB. Aprotinin, as an antiiflammatory agent, may decrease the release of such vasoactive substance from pulmonary tissues, preventing pulmonary hypertension after cardiopulmonary bypass. MATERIAL AND METHOD: Ten mongrel dogs(Bwt. ac. 20kg) were subjected to cardioupulmonary bypass for 2 hours and postbypass pulmonary vascular resistance(0, 1, 2, 3 hours) were compared with prebypass level. The dogs were divided into 2 groups; control group(n-5) and aprotinin group(n=5). In the aprotinin group, aprotinin was administered as follows; 50,000 KIU/kg mixed in pump priming solution, 50,000 KIU/kg prebypass intravenous infusion over 30 minutes, 10,000 KIU/kg/hour postbypass continuous infusion. Prebypass and postbypass 0, 1, 2, 3 hour pulmonary vascular resistance were measured. At prebypass and postbypass 0, 90, 180 minutes, blood samples were obtained from pulmonary arterial and left atrial catherers for the assay of plasma thromboxane B2 a stable metabolite of thromboxane A2, and endothelin-1 concentrations. RESULT: The ratios of pustbypass over prebypass pulmonary vascular at postbypass 0, 1, 2, 3 hours were 1.28+/-0.20, 1.82+/-0.23, 1.90+/-0.19, 2.14+/-0.18 in control group, 1.58+/-0.18, 1.73+/-0.01, 1.66+/-0.10, 1.50+/-0.08 in aprotinin group ; the ratios gradually increased in control group while decreased or fluctuated after postbypass 1 hour in aprotinin group. There was statistically significant difference between control group and aprotinin group at postbypass 3 hours(P=0.014). Pulmonary arterial plasma concentration of thromboxane B2(pg/ml) at prebypass, postbypass 0, 90, 180 minutes were 346.4+/-61.9, 529.3+/-197.6, 578.3+/-255.8, 493.3+/-171.3 in control group, 323.8+/-118.0, 422.6+/-75.6, 412.3+/-59.9, 394.5+/-154.0 in aprotinin group. Left atrial concentrations were 339.3+/-89.2, 667.0+/-65.7, 731.2+/-192.7, 607.5+/-165.9 in control group, 330.0+/-111.2, 468.4+/-190.3, 425.4+/-193.6, 4.7.3+/-142.8 in aprotinin group. These results showed decrement of pulmonary thromboxane A2 generation in aprotinin group. Pulmonary arterial concentrations of endothelin-1(fmol/ml) at the same time sequence were 7.84+/-0.31, 13.2+/-0.51, 15.0+/-1.22, 16.3+/-1.73 in control group, 7.76+/-0.12, 15.3+/-0.71, 22.6+/-6.62, 14.9+/-1.11 in aprotinin group. Left atrial concentrations were 7.61+/-17.2, 57.1+/-28.4, 18.9+/-18.2, 31.5+/-20.5 in control group, 5.61+/-7.61, 37.0+/-26.2, 28.6+/-21.7, 37.8+/-30.6 in aprotinin group. These results showed that aprotinin had no effect on plasma endothelin-1 concentration after cardiopulmonary bypass. CONCLUSIONS: Administration of aprotinin during cardiopulmonary bypass could attenuate the increase in pulmonary vascular resistance after bypass. Inhibition of pulmonary thromboxane A2 generation was thought to be one of the mechanism of this effect. Aprotinin had no effect on postbypass endothelin-1 concentration.
Animals ; Aprotinin* ; Cardiopulmonary Bypass ; Dogs ; Endothelin-1* ; Endothelins ; Extracorporeal Circulation* ; Hypertension, Pulmonary ; Infusions, Intravenous ; Plasma* ; Thromboxane A2 ; Thromboxane B2* ; Vascular Resistance ; Vasoconstrictor Agents

BACKGROUND: Conventional cardiac transplantation with each atrial anastomosis designed by Shumway and associates has been used widely in cardiac transplantation because of its simplicity and efficiency. There have been many reports about the postoperative atrioventricular value regurgitation resulting from the alteration in atrial geometry after cardiac transplantation by Shumway's technique. New surgical technique of direct anastomosis of superior vena cava, inferior vena cava, right pulmonary vein and left pulmonary vein was introduced to overcome the those problems. We performed this study to test the feasibility of this new surgical technique prior to application to clinical practice. MATERIAL AND METHOD: Conventional cardiac transplantation was performed on 12 mongrel dogs(Group I) and cardiac transplantation with new surgical mthod of direct anastomosis of SVC, IVC, left and right pulmonary veins was performed on 11 mongrel dogs(Group II). After weaning from cardiopulmonary bypass, we compared the postoperative rhythm, hemodynamic data, and echocardiographic findings between two groups. RESULT: The cardiopulmonary bypass time and graft ischemic time were 119.0+/-4.4 minutes, 162.0+/-4.5 minutes respectively in group I, and 140.0+/-7.1 minutes, 180.5+/-5.4 minutes respectively in group II. The cardiopulmonary time and graft ischemic time in group II were longer than those of group I (p<0.05). There were 3 cases of failure to weaning from cardipulmonary bypass onein group I and two in group II, and this difference was not significant statistically. Sinus rhythm was regained postoperatively in 58% (group I) and 82%(group II), without statistical significant between 2 groups. Postoperative echolcardiography showed 2 cases of tricuspid value regurgitation and 1 case of mitral regurgitation in group I, and no regurgitation of atrioventricular value in group II. CONCLUSIONS: Although these was no statistically significant difference between 2 groups, there was tendency of less arrhythmia and less atrioventricular valvular regurgitation in group II. We suggested that the new surgical technique could be a useful strategy in heart transplantation, especially in the case of size mismatching between donor and recipient.
Animals ; Arrhythmias, Cardiac ; Cardiopulmonary Bypass ; Dogs* ; Echocardiography ; Heart Transplantation* ; Heart* ; Hemodynamics ; Humans ; Mitral Valve Insufficiency ; Pulmonary Veins ; Tissue Donors ; Transplants ; Vena Cava, Inferior ; Vena Cava, Superior ; Weaning

BACKGROUND: Patients with tetralogy of Fallot(TOF), pulmonary atresia(PA) and major aortopulmonary collateral arteries(MAPCAs) have been managed by heterogenous surgical strategies. We have taken 5 different surgical approaches to this lesion. In this study, relative advantages and disadvantages of each strategy were discussed by analyzing our surgical results. MATERIAL AND METHOD: Between January 1986 and June 1998, 50 patients aged 1 to 177(39+/-31) months at a various morphologic spectrum of this lesion were treated at our institution. The groups, which were classified according to the initial approaches, consisted of one-stage unifocalization(A-1, n=9), staged unifocalization(A-2, n=11), right ventricle to pulmonary artery connection(RV-PA)(B-1, n=11), one-stage RV-PA plus unifocalization (B-2, n=11), and one-stage definitive repair(C, n=8). Morphologic charateristics, operative mortalities, and probabilities of definitive repair were compared between the groups and the causes of death, complications and the follow-up results were described. RESULT: Mean ages at the first operation were 57+/-18(A-1), 42+/-48(A-2), 18+/-14(B-1), 52+/-55(B-2), and 32+/-34(C) months (p<0.05). Mean numbers of MAPCAs were least in group C (A-1=4.3+/-1.0, A-2=4.5+/-1.3, B-1=4.1+/-1.9, B-2=4.1+/-1.6, C=3.4+/-1.8 : p<0.05). The ratios of the direct and the indirect MAPCAs in each group were not different between the grousps (A-1=91%/9%, A-2=78%/22%, B-1=80%/20%, B-2=80%/20%, C=81%/19% : p>0.05). Nineteen patients had more than 1 dependent MAPCAs. True pulmonary arteries were not present 13 patients and they were confluent in 29. A total of 101 operations were performed. Operative mortalities of initial procedures were 33%(3/9, A-1), 18%(2/11, A-2), 0%(0/11, B-1), 36%(5/11, B-2) and 13%(1/8, C) (p<0.05). Percentages of the definitive repair among the patients of each group were 22%(2/9, A-1), 18%(2/11, A-2). 45%(5/11, B-1), 27%(4/11, B-2), and 100%(8/8, C)(p<0.05). Hypoxic respiratory and cardiac failure(6), hypoxic encephalopathy(2) and sepsis(4) were the major causes of death. Phrenic nerve palsy occured in 5 patients. Thirty-one patients among the survivals have been followed up for a mean duration of 74+/-42(3-145) months. One and five year actuarial survival rates were 73% and 73 %. CONCLUSION: In conclusion, Right ventricle to pulmonary artery connection used in patients with TOF/PA/MAPCA as an inital procedure appeared to be highly successful in enhancing the chance of satisfactory definitive repair without the significant surgical risks. One-stage total repair at an ealier age group could be performed safely with the resonable outcomes. Unifocalization approach, whether it was performed in a single stage or in the multiple stages, resulted in the high operative mortality and the lowest chance of definitive repair, however more tailored selection of the patients and the long follow-up is mandatory to prove the usefulness of this approach.
Arteries* ; Cause of Death ; Follow-Up Studies ; Heart Ventricles ; Humans ; Mortality ; Paralysis ; Phrenic Nerve ; Pulmonary Artery ; Pulmonary Atresia* ; Survival Rate ; Tetralogy of Fallot*

BACKGROUND: To evaluate the risk factor and long-term result of arterial switch operation , a retrospective study was done. MATERIAL AND METHOD: A retrospective analysis was done to evaluate the early and long-term results on 58 patients who underwent an arterial switch operation(ASO) for transposition of the great arteries(TGA) with intact ventricular septum, between January 1988 and December 1996. Beforesurgery, 36 patients(62.1%) underwent balloon atrial septostomy, 32 patients(51.7%) received PGE1 infusion, and preparatory banding of pulmonary artery was performed on 6 patients(mean LV/RV pressure ratio 0.53+/-0.11). RESULT: The age at operation ranged from 1 to 137 days(mean 24+/-26 days) and the weights ranged from 1.8 to 6.8 kg (mean 3.5+/-0.8 kg). There were 14 early deaths(24.1%), but of the last 24 patients operated on since 1994, there were only 2 early deaths(8.3%). In the risk factor analysis, the date of operation was the only risk factor for early death(p-value <0.01). Eight of the 14 early deaths were due to acute myocardial failure(mainly inadequate coronary blood flow). The length of follow-up ranged from 2 months to 8 years, average of 36+/-27 months. The follow-up included sequential noninvasive evaluations and 21 catheterizations and angiographic studies performed 5 to 32 months postoperatively with particular attention to the great vessel and coronary anastomosis, ventricular function, valvular competence, and cardiac rhythm. There were 5 late deaths(11.4%), one of thesedeaths was related to the late coronary problems, two to aspiration, one to uncontrolled chronic mediastinitis, and one to progressive aortic insufficiency and heart failure. The most frequent postoperative hemodynamic abnormality was supravalvular stenosis and the degree of pulmonary or aortic obstruction had slowly progressed in some cases, however there were no children who had to undergo a reoperation for supravalvular pulmonary or aortic stenosis. Aortic regurgitation was identified in 9 patients, which was mild in 7 and moderate in 2 and had progressed in some cases. Two patients who had an unremarkable perioperative course were identified as having coronary artery obstructions. The other late survivors were in good condition, were in sinus rhythm, and had normal LV functions. Actuarial survival rate at 8 years was 68.8%. CONCLUSION: We concluded that anatomic correction will be established as the optimal approach to the TGA with intact ventricular septum, though further long-term evaluations are needed.
Alprostadil ; Aortic Valve Insufficiency ; Aortic Valve Stenosis ; Arteries* ; Catheterization ; Catheters ; Child ; Constriction, Pathologic ; Coronary Vessels ; Follow-Up Studies ; Heart Failure ; Hemodynamics ; Humans ; Mediastinitis ; Mental Competency ; Pulmonary Artery ; Reoperation ; Retrospective Studies ; Risk Factors* ; Survival Rate ; Survivors ; Transposition of Great Vessels ; Ventricular Function ; Ventricular Septum* ; Weights and Measures

BACKGROUND: We analyzed five hundred patients who underwent either isolated or concomitant coronary artery bypass grafting(CABG) between November 1981 and June 1997. MATERIAL AND METHOD: There were 330 males and 170 females with a mean age of 57.4+/-8.9 years. To evaluate the preoperative status, we performed electrocardiograghy, echocardiography, MIBI scan, Duplex sonogram, common blood test including CK and LDH and coronary angiography. RESULT: Preoperative clinical diagnoses were unstable angina in 282 (56.4%), stable angina in 141 (28.2%), postinfarction angina in 58 (11.6%), acute myocardial infarction in 8 (1.6%), variant angina in 7 (1.4%) and failed percutaneous transluminal coronary angioplasty in 4 (0.8%) patients. Preoperative angiographic diagnoses were three-vessel disease in 263 (52.6%), two-vessel disease in 93 (18.6%), one-vessel disease in 71 (14.2%), left main disease in 68 (13.6%), and others in 5 (1.0%) patients. Patients had various risk factors for coronary disease, and the frequency of the risk factors such as hypertension, diabetes and smoking showed increasing tendency year by year. We used saphenous vein grafts in 1143, internal thoracic artery grafts in 442, radial artery graft in 17, and gastroepiploic artery graft in 1 anastomosis. The mean number of grafts was 3.2+/-1.2 per patient. Concomitant operations were prosthetic valve replacement or valvuloplasty in 31, coronary endarterectomy and angioplasty in 27, left main coronary angioplasty in 13, carotid endarterectomy in 5, and neurologic problems, bleeding, and perioperative myocardial infarction. The mean follow-up period was 25+/-23 months and there were 5 cases of reoperation. CONCLUSION: We hope that the surgical results would improve with the accumulation of experience, application of new myocardial protection technique, and timely intervention of mechanical assisted devices.
Angina, Stable ; Angina, Unstable ; Angioplasty ; Angioplasty, Balloon, Coronary ; Coronary Angiography ; Coronary Artery Bypass* ; Coronary Disease ; Coronary Vessels* ; Diagnosis ; Echocardiography ; Endarterectomy ; Endarterectomy, Carotid ; Female ; Follow-Up Studies ; Gastroepiploic Artery ; Hematologic Tests ; Hemorrhage ; Hope ; Humans ; Hypertension ; Male ; Mammary Arteries ; Myocardial Infarction ; Radial Artery ; Reoperation ; Risk Factors ; Saphenous Vein ; Smoke ; Smoking ; Transplants

BACKGROUND: This study has proven the effect of modified ultrafiltration(MUF) performed after the cessation of cardiopulmonary bypass in pediatric patients who underwent open heart surgery. MATERIAL AND METHOD: From Jan. to Dec. 1997, modified ultrafiltration was performed after cardiopulmonary bypass in 50 infants with cyanotic heart disease and the results were compared to the control group of 50 patients with cyanotic heart disease in whom modified ultrafiltration was not used. Changes of hematocrit, central venous pressure, systolic and diastolic pressure, heart rate and body weight were compared. RESULT: Age and body weight were not different(p=0.38, p=0.46). Disease categories were similar. Average filtering volume was 60.0+/-29.2cc/kg for 7.0+/-2.4minutes of filtration. Mean hematocrit after filtration(MUF=36.1%, control=26.4%, p=0.001) was higher in the MUF group. Systolic (p=0.0001) and diastolic blood pressure(p=0.0001) were observed to increase more and the central venous pressure(p=0.02) and the heart rate(p=0.02) were lower after filtration in the MUF group. CONCLUSION: This study demonstrated that modified ultrafiltration after cardiopulmonary bypass was a technically feasible option to improve the post-surgical course through the effective hemoconcentration, hemodynamic improvements, and body water control.
Blood Pressure ; Body Water ; Body Weight ; Cardiopulmonary Bypass ; Central Venous Pressure ; Filtration ; Heart Diseases ; Heart Rate ; Heart* ; Hematocrit ; Hemodynamics ; Humans ; Infant ; Thoracic Surgery* ; Ultrafiltration*

BACKGROUND: Sixty five cases with congenitally corrected transposition of the great arteries (CCTGA) indicated for biventricular repair were operated on between 1984 and september 1998. Comparison between the results of the conventional(classic) connection(LV-PA) and the anatomic repair was done. MATERIAL AND METHOD: Retrospective review was carried out based on the medical records of the patients. Operative procedures, complications and the long-term results accoding to the combining anomalies were analysed. RESULT: Mean age was 5.5+/-4.8 years(range, 2 months to 18years). Thirty nine were male and 26 were female. Situs solitus {S,L,L} was in 53 and situs inversus{I,D,D} in 12. There was no left ventricular outflow tract obstruction(LVOTO) in 13(20%) cases. The LVOTO was resulted from pulmonary stenosis(PS) in 26(40%)patients and from pulmonary atresia(PA) in 26(40%) patients. Twenty-five(38.5%) patients had tricuspid valve regurgitation(TR) greater than the mild degree that was present preoperatively. Twenty two patients previously underwent 24 systemic- pulmonary shunts previously. In the 13 patients without LVOTO, 7 simple closure of VSD or ASD, 3 tricuspid valve replacements(TVR), and 3 anatomic corrections(3 double switch operations: 1 Senning+ Rastelli, 1 Senning+REV-type, and 1 Senning+Arterial switch opera tion) were performed. As to the 26 patients with CCTGA+VSD or ASD+LVOTO(PS), 24 classic repairs and 2 double switch operations(1 Senning+Rastelli, 1 Mustard+REV-type) were done. In the 26 cases with CCTGA+VSD+LVOTO(PA), 19 classic repairs(18 Rastelli, 1 REV-type), and 7 double switch operations(7 Senning+Rastelli) were done. The degree of tricuspid regurgitation increased during the follow-up periods from 1.3+/-1.4 to 2.2+/-1.0 in the classic repair group(p<0.05), but not in the double switch group. Two patients had complete AV block preoperatively, and additional 7(10.8%) had newly developed complete AV block after the operation. Other complications were recurrent LVOTO(10), thromboembolism(4), persistent chest tube drainage over 2 weeks(4), chylothorax(3), bleeding(3), acute renal failure(2), and mediastinitis(2). Mean follow-up was 54+/-49 months(0-177 months). Thirteen patients died after the operation(operative mortality rate: 20.0%(13/65)), and there were 3 additional deaths during the follow up period(overall mortality: 24.6%(16/65)). The operative mortality in patients underwent anatomic repair was 33.3%(4/12). The actuarial survival rates at 1, 5, and 10 years were 75.0+/-5.6%, 75.0+/-5.6%, and 69.2+/-7.6%. Common causes of death were low cardiac output syndrome(8) and heart failure from TR(5). CONCLUSION: Although our study could not demonstrate the superiority of each classic or anatomic repair, we found that the anatomic repair has a merit of preventing the deterioration of tricuspid valve regurgitations. Meticulous selection of the patients and longer follow-up terms are mandatory to establish the selective advantages of both strategies.
Arteries* ; Atrioventricular Block ; Cardiac Output, Low ; Cause of Death ; Chest Tubes ; Drainage ; Female ; Follow-Up Studies ; Heart Failure ; Humans ; Male ; Medical Records ; Mortality ; Retrospective Studies ; Surgical Procedures, Operative ; Survival Rate ; Tricuspid Valve ; Tricuspid Valve Insufficiency

BACKGROUND: We prospectively investigated types, incidences, and risk factors for arrhythmias after open heart surgery in adults. MATERIALS AND METHODS: From June 1994 to May 1995, we performed 302 cases of adult cardiac surgery at our department. This study group consisted of 150 men and 152 women, with a mean age of 43.9+/-28.0 (range 16 to 75)years. We included all the patients irrespective of their operative types or disease entities. RESULTS: The overall incidence of arrhythmias after open heart surgery in adults was 58.3%. The incidence of postoperative arrhythmias for redo-valvular heart surgery was 77.8%, and those for simple valvular procedure, coronary artery bypass surgery, aortic surgery, and congenital heart disease were 70.8%, 45.3%, 40.0%, and 29.5%, respectively. Eight out of twelve risk factors showed statistical significance for the development of postoperative arrhythmias. They were preoperative history of arrhythmias, antiarrhythmic drug medication, previous cardiac surgery, larger left ventricular end-diastolic, end-systolic dimension, left atrial dimension on preoperative echocardiogram, longer cardiopulmonary bypass time and aortic cross clamping time. Univariated analyses for age and types of cardioplegic solution did not show statistical significance. CONCLUSIONS: Prospective study on postoperative arrhythmias occurrence, treatment and prevention of is warrauted to draw more clear conclusion.
Adult* ; Arrhythmias, Cardiac* ; Cardioplegic Solutions ; Cardiopulmonary Bypass ; Constriction ; Coronary Artery Bypass ; Female ; Heart Defects, Congenital ; Heart* ; Humans ; Incidence ; Male ; Postoperative Complications ; Prospective Studies ; Risk Factors ; Thoracic Surgery*

BACKGROUND: This study is to evaluate the effectiveness and application of Lecompte procedure as a treatment for various complex cardiac anomalies with pulmonary outflow tract obstruction. Methods: Between July 1988 and December 1997, 44 patients underwent Lecompte procedure in Seoul National University Children's Hospital. The male to female ratio was 24 to 20 and the mean age was 29.2 months (range, 3 to 83). Of these patients, 28 (63.6%) had transposition of great arteries with ventricular septal defect and pulmonary stenosis (or pulmonary atresia), 14 (31.8%) had double outlet right ventricle with pulmonary stenosis (or pulmonary atresia), and so on. The principles of the technique are 1) extension of the ventricular septal defect or conal resection, 2) construction of a intracardiac tunnel connecting the left ventricle to the aorta, and 3) direct connection, without a prosthetic conduit, of the pulmonary trunk to the right ventricle. RESULTS: There were 3 in-hospital deaths and their causes were sustained hypoxia, myocardial failure, and sepsis, respectively. There was 1 late death due to sepsis. Reoperations were performed in 6 patients who had pulmonary outflow tract obstructions (4 cases), residual muscular ventricular septal defect (1 case), and recurrent septic vegetation (1 case). The cumulative survival rates by the Kaplan-Meier method were 92.7%, 92.7%, and 92.7% at 1, 2, and over 4 years. The reoperation free survival rates were 92.7%, 92.7%, and 70.2% at 1, 3, and over 5 years. Among the risk factors for the operative death, aortic cross clamping time had statistical significance (p<0.05) and all the risk factors for the recurrent pulmonary stenosis such as age, pulmonary artery index, and materials used for the pulmonary outflow tract reconstruction had no statistical significance (p>0.05). CONCLUSIONS: Our review suggests that Lecompte procedure is an effective treatment modality for various complex cardiac anomalies with pulmonary outflow tract obstruction. Repair in early age is possible and the rates of mortality and morbidity are also acceptable.
Anoxia ; Aorta ; Constriction ; Double Outlet Right Ventricle ; Female ; Heart Diseases* ; Heart Failure ; Heart Septal Defects, Ventricular ; Heart Ventricles ; Heart* ; Humans ; Male ; Mortality ; Pulmonary Artery ; Pulmonary Valve Stenosis ; Reoperation ; Risk Factors ; Seoul ; Sepsis ; Survival Rate ; Transposition of Great Vessels

We report a case of heart-lung transplantation in a 32 year-old female with Eisenmenger syndrome secondary to patent ductus arteriosus. She has been suffered from congestive heart failure since June 1996 and repeatedly treated at Intensive Care Unit with intravenous inotropic support since July 1997. Preoperative echocardiography showed a patent ductus arteriosus with right to left shunt, severe regurgitation of tricuspid valve and estimated right ventricular systolic pressure of 100mmHg. The brain-dead donor was an 18 year-old male with head trauma from traffic accident 3 days ago. Heart-lung block procurement was performed at another general hospital and was transported to the Seoul National University Hospital by ambulance. Total ischemic time of the transplanted heart and lung were 249 minutes and 270 minutes, respectively. The immunosuppressive therapy was commenced preoperatively with cyclosporine and azathioprine. Corticosteroid was not used until postoperative 3 weeks in order to avoid infection and delayed healing at the tracheal anastomotic site. The patient was discharged at 31st postoperative day, and has been regularly followed up at outpatient clinic without specific complication. The follow-up bronchoscopy, performed 2 weeks and 4 months after surgery, revealed no evidence of cellular rejection.
Accidents, Traffic ; Adolescent ; Adult ; Ambulances ; Ambulatory Care Facilities ; Azathioprine ; Blood Pressure ; Bronchoscopy ; Craniocerebral Trauma ; Cyclosporine ; Ductus Arteriosus, Patent ; Echocardiography ; Eisenmenger Complex ; Female ; Follow-Up Studies ; Heart ; Heart Failure ; Heart-Lung Transplantation* ; Hospitals, General ; Humans ; Intensive Care Units ; Lung ; Male ; Seoul ; Tissue Donors ; Tricuspid Valve