Persistent left superior vena cava: the anatomical and surgical importance.

OBJECTIVE: Persistence of the left superior vena cava (PLSVC) is a congenital anomaly resulting from failure of degeneration of the left cardinal vein. The prevalence of this anatomical variant is approximately 0.3% in the general population. The aim of this study was to determine the prevalence of the persistence of the left superior vena cava in order to avoid potential complications. SUBJECTS AND METHODS: The study was conducted during a five-year period in 152 patients (64 males, 88 females) aged 1-65 years who underwent cardiac surgery for congenital heart diseases. RESULTS: The persistence of the left superior vena cava was found in 5 of 152 patients (3.3%). All persistent left superior vena cavae opened into the coronary sinus. Furthermore, the coronary sinus was enlarged in all patients. The right superior vena cava was absent in one of the five cases (20%) in this study. CONCLUSION: This anatomical variant must be recognized to avoid the potential complications.

Persistent left superior vena cava: the anatomical and surgical importance / Vena cava superior izquierda persistente Importancia anatómica y quirúrgica

OBJECTIVE: Persistence of the left superior vena cava (PLSVC) is a congenital anomaly resulting from failure of degeneration of the left cardinal vein. The prevalence of this anatomical variant is approximately 0.3in the general population. The aim of this study was to determine the prevalence of the persistence of the left superior vena cava in order to avoid potential complications. SUBJECTS AND METHODS: The study was conducted during a five-year period in 152 patients (64 males, 88 females) aged 1-65 years who underwent cardiac surgery for congenital heart diseases. RESULTS: The persistence of the left superior vena cava was found in 5 of 152 patients (3.3). All persistent left superior vena cavae opened into the coronary sinus. Furthermore, the coronary sinus was enlarged in all patients. The right superior vena cava was absent in one of the five cases (20) in this study. CONCLUSION: This anatomical variant must be recognized to avoid the potential complications.

Objetivo: La persistencia de la vena cava superior (PVCSI) es una anomalía congénita que se presenta como resultado de un fallo degenerativo en la vena cardinal izquierda. La prevalencia de esta variante anatómica es aproximadamente 0.3% en la población general. El objetivo de este estudio es determinar la prevalencia de la persistencia de de la vena cava superior izquierda a fin de evitar complicaciones potenciales. Sujetos y métodos: El estudio fue realizado durante un periodo de cinco años en 152 pacientes (64 varones, 88 hembras) de 1 65 años, que fueran sometidos a cirugía cardíaca debido a enfermedades cardiacas congénitas. . Resultados: Se halló persistencia de la vena cava superior izquierda en 5 de 152 pacientes (3.3%). Todas las venas cavas superiores izquierdas desembocan en el seno coronario. Además, el seno coronario de todos los pacientes presentaba un ensanchamiento. No habia vena cava superior en uno de los cinco casos (20%) de este estudio. Conclusión: Esta variante anatómica tiene que ser reconocida a fin de evitar potenciales complicaciones.

Laryngeal mask airway insertion with remifentanil.

INTRODUCTION: We conducted a study to find out the best conditions for LMA insertion with two different doses of remifentanil added to propofol and propofol administered alone. METHODS: Following hospital clinical research ethics committee approval, 60 ASA I-II patients were included in the randomized double-blind study. Following premedication, patients received i.v. 0.25 microg kg(-1) remifentanil (Group R1), 0.50 microg kg(-1) remifentanil (Group R2) or normal saline (Group P) in 60 sec. Then following 20 mg lidocaine, propofol 2 mg kg(-1) were administered in R1 and R2 groups and 2.5 mg kg(-1) in P group. Ease of insertion of LMA and airway quality at first attempt was assessed. Number of attempts of LMA insertion, apnea time, additional propofol requirement and hemodynamic changes were recorded. RESULTS: There were no significant differences in demographic data among the patients. Apnea time (mean +/- SEM) was significantly shorter in P group (34.09 +/- 5.5 sec) compared to R1 (82.5 +/- 12.7 sec) and R2 (87.2 +/- 6.6 sec) groups (p = 0.01 and p = 0.001). Ease of LMA insertion was assessed as grade 1 in 100% of patients in R2 group while 65% in R1 and 30% in P groups. Undesirable responses following LMA insertion were observed in 54% of patients in P group. CONCLUSION: Propofol given 2.5 mg kg(-1) alone is not a good agent for LMA insertion. Remifentanil used in both doses combined with propofol provides good and excellent conditions for insertion of LMA with minimal hemodynamic disturbances.

Comparison of 21-23 size St. Jude medical valves to the 27-29 size mechanical valves in aortic position. Ten-year follow-up.

BACKGROUND: Between 1986 and 1996, 194 patients underwent isolated aortic valve replacement with 21-23 no. St. Jude Medical mechanical heart valves (small sized group) and 163 patients with 27-29 no. (large sized group). METHODS: The mean age at operation was 45.04+/-15.90 years (range: 12-76 years) for the small sized group and 38.05+/-13.41 years (range: 16-68 years) for the large sized group. Preoperatively, 39.7% of the patients from the small sized group and 42.9% from the large sized group had pure aortic stenosis, 31.9% and 27.6% had pure aortic insufficiency. Most of the patients had rheumatic valve disease. RESULTS: The overall hospital mortality rate was 12.4% and 3.07% respectively in the small sized and large sized groups (p<0.001). The overall actuarial survival rate for 10 years was 95.33+/-2.73% and 93.06+/-3.98% respectively in the small sized group and large sized group (p>0.05). In the small sized group male sex and all complications, in large sized group age and all complications were the statistically important hospital mortality predictors (p<0.05). CONCLUSIONS: Although, operative mortality and long term morbidity were higher in the small sized group, these changes did not reflect the actuarial survivals between the groups. Small sized valves carry some risk, but these risks do not affect long-term survival.

Experimental inhibition of protamine cardiotoxicity by prostacyclin.

Twelve animals (26+/-5 kg) were subjected to the study. In this experimental study, the authors used prostacyclin to inhibit the toxic metabolite release during protamine administration. Animals were divided into two equal groups. Six animals received prostacyclin (the prostacyclin group), and the other six animals did not receive any additional treatment (the control group). All cardiac output and biochemical measurements were evaluated at baseline; before cardiopulmonary bypass; and at 5, 30, and 60 minutes after protamine administration. The measured cardiac index showed that the hearts treated with prostacyclin had satisfactory preservation of left ventricular function. Metabolic and biochemical data showed that the tumor necrosis factor level was raised significantly in the control group (20.75+/-2.2 in the control group and 13.75+/-2.5 pg/mL in the prostacyclin group). Also, E and P selectin levels were elevated in the control group, but this change was less marked in the prostacyclin group. In addition, the intracellular adhesion molecule-1 (ICAM-1) level was significantly higher in the control group than in the prostacyclin group (9.26+/-2.13 in the control group and 5.13+/-1.66 ng/mL in the prostacyclin group). The authors observed that prostacyclin inhibited the toxic mediator release during heparin reversal with protamine. This inhibition is one way of protecting the myocardium reserves from protamine cardiotoxicity.

A clinical dilemma: cardiac and pericardiac echinococcosis.

BACKGROUND: Cardiac and pericardial echinococcosis as a life-threatening disease may present with a clear picture most of the time, however it may also become a clinical puzzle. METHODS: In the period between 1977 and 1998, 14 patients were operated on with the diagnosis of cardiac and pericardial echinococcosis. Nine patients were operated on with standard cardiopulmonary bypass (CPB) techniques, and the remaining 5 patients were operated on without CPB. Transesophageal echocardiography (TEE) or intraoperative surface echocardiography were used to plan and perform the operation for the late cases. RESULTS: One patient died during the postoperative period due to the rupture of interventricular septum. All other patients survived the perioperative period, received mebendazole treatment, and exhibited no recurrence during the follow-up. CONCLUSIONS: The definitive treatment is the surgical extraction of the cyst. Because the clinical picture may vary according to the number, size, and location of cysts, as well as complications, cardiac echinococcosis should be remembered and included in the differential diagnosis to achieve the treatment. Intraoperative surface echocardiography is of paramount value for diagnosis and planning the management of a successful surgery.

ATP-MgCl2 utilization for spinal cord protection during experimental thoracic aortic occlusion.

BACKGROUND: In this experimental study we investigate the effect of intravenous ATP-MgCl**2 administration for prevention of spinal cord injury occurring due to ischemia induced by aortic cross clamping. METHODS: Ten rabbits were studied. The abdominal aorta is ligated below the left renal artery. Five rabbits served as a control group and received no medication during 30 minutes of ischemic period. The other 5 rabbits received during 30 minutes of aortic occlusion ATP-MgCl2 solution (100 micromol/ml for each). Distal and proximal aortic pressures are measured during the procedure and incisions are closed. Rabbits are observed for 24 hours for their neurological status and scored accordingly. Specimens from the spinal cord are taken for electron microscopic investigations. RESULTS: All of the control group rabbits were paraplegic. One of the ATP-MgCl2 group rabbits was paraparesic and the others were normal Distal aortic pressure was 9+/-3 mmHg for the control group and was 17+/-4 mmHg for the ATP-MgCl2 group (p<0.05). Electron microscopic studies showed the preserved ultrastructure for ATP-MgCl2 group. CONCLUSIONS: ATP-MgCl2 administration during spinal cord ischemia reduces spinal cord injury. This may be an alternative modality for the protection of the spinal cord during aortic surgery.

Experimental evaluation of retrograde cerebral perfusion by single photon emission computed tomography technique (SPECT).

BACKGROUND: Protection of the brain is of vital importance during aortic arch aneurysms. In this study efficiency of retrograde cerebral perfusion was evaluated with the use of single photon emission computed tomography technique (SPECT) by using 99mTc hexamethylpropylene amine oxime (HMPAO). METHODS: Four animals were used. The internal maxillary vein was the site of retrograde cerebral perfusion. The animals were studied after the heart rate and respiration were stopped with the use of the high dose drug administration and the brain was perfused with cold Ringer's lactated solution. After this procedure, 99mTc HMPAO-SPECT study was performed. RESULTS: In one animal we did not get any cerebral image because of the competent venous valve in the internal maxillary vein. In the remaining animals, normal brain perfusion was achieved. CONCLUSIONS: 99mTc HMPAO-SPECT study documented that blood flow via the retrograde way meets the metabolic demand of the brain. Retrograde delivery of 99mTc HMPAO did not conclude any poorly perfused area in the brain when in given both sides and all parts of the brain can be effectively perfused by cerebral venous system in hypothermic conditions.

Coronary sinus retroperfusion during acute experimental coronary artery occlusion.

BACKGROUND: This study was planned to show the effect of retroperfusion and cardiopulmonary bypass on myocardial hemodynamic recovery. METHODS: Eighteen dogs entered this study. After, left anterior descending artery (LAD) was dissected and occluded, the animals were divided into three equal groups; Group I: retrograde coronary sinus perfusion, group II: cardiopulmonary bypass and retrograde coronary sinus perfusion, Group III: control group, left anterior descending artery occlusion only. RESULTS: In Group III, deterioration of the hemodynamic values progressed parallel with the degree of ischemic damage but in Group I, hemodynamic parameters were better because of the retrograde coronary sinus perfusion and minimally affected by the reperfusion. In Group II, at the end of the cardiopulmonary bypass minimal myocardial damage was observed. CONCLUSIONS: There is no statistical difference between Group I and II if we examine the data that was taken after reperfusion although myocardial performance was better in Group II.

Perinatal mitral valve interventions: a report of 10 cases.

BACKGROUND: Rheumatic mitral valve stenosis is still an endemic disease in some parts of the world and may complicate pregnancy and perinatal period. During the 10-year period between January 1988 and December 1997, 10 pregnant women with mitral stenosis were operated on. METHODS: Combined cesarean delivery and closed mitral valvulotomy (CMV) were performed on 6 patients, combined cesarean delivery and Mitral Valve Replacement (MVR) were performed on 1 patient, and 3 patients had CMV during their third trimester. RESULTS: There was 1 stillbirth. All other patients and delivered babies were healthy. MVR was necessary for mitral restenosis in one patient 5 years after her CMV. Three of the remaining patients had some degree of restenosis but did not require reoperation. CONCLUSION: CMV when indicated during pregnancy can be performed with low risk. For symptomatic patients responding to medical therapy, a combined approach of cesarean section and CMV will prevent possible complications that may arise on perinatal period due to hemodynamic fluctuation.

Comparison of reoperation findings of the Carpentier-Edwards (standard) bioprosthesis and the St Jude bioimplant (formerly Liotta) in the mitral position.

Between 1986 and 1996, 50 patients with Carpentier-Edwards porcine bioprostheses and 211 with a St Jude bioprosthesis underwent reoperation because of structural valve deterioration. Structural valve deterioration was defined as an intrinsic abnormality of the prosthesis (leaflet disruption, calcification, leaflet thickening, etc.) that caused stenosis or regurgitation found on physical examination and echocardiography. Fifteen of the Carpentier-Edwards bioprosthesis group were male and 35 were female. Eighty-two of the St Jude group were male and 129 female. The mean age at reoperation was 33.88 +/- 10.31 years (range 19-70) for the Carpentier-Edwards group and 39.03 +/- 9.97 years (range 20-70) for the St Jude group. The average duration was 94.32 +/- 3.83 months for the Carpentier-Edwards group and 73.76 +/- 1.44 months for the St Jude group (P < 0.001). The mean aortic cross-clamp time was 67.4 min (minimum 32, maximum 210) for the St Jude group and 63.21 min (minimum 36, maximum 230) for the Carpentier-Edwards group. Reoperative hospital mortality was 10% (5/50) in the Carpentier-Edwards group and 7.1% (15/211) in the St Jude group (P > 0.05). Late failure modes of the bioprostheses were defined for the purposes of this study as calcification, stenosis and torn leaflets. Of the Carpentier-Edwards group, seven patients (14%) developed calcification, six patients (12%) developed stenosis and 13 patients (26%) developed leaflet tears. Of the St Jude group, the incidences were 22 patients (10%), 67 patients (31.8%) and 87 patients (41%), respectively. This study indicates that the Carpentier-Edwards bioprosthesis is more durable than the St Jude. The St Jude bioprosthesis tended to develop leaflet tears and linear calcification in female patients, and nodular calcification in male patients.

Low-dose oral anticoagulation and antiplatelet therapy with St. Jude Medical heart valve prosthesis.

BACKGROUND AND AIM OF THE STUDY: Since 1986, the St. Jude Medical (SJM) mechanical heart valve prosthesis has been implanted in patients at the authors' institution. We present our experience of low-dose oral anticoagulation and antiplatelet therapy following SJM valve implantation. METHODS: Among 2,585 patients (mean age 40.3 +/- 13.5 years) living in a rural environment, 865 underwent aortic valve replacement (AVR), 1,231 mitral valve replacement (MVR) and 489 double valve replacement (DVR). All patients received 2.5 mg/day warfarin and a combination of antiaggregation therapy (dypridamole 3 x 75 mg/day plus aspirin 100 mg/day), irrespective of their prothrombin time and cardiac rhythm. RESULTS: Postoperatively, 139 adverse events occurred (51 in AVR patients, 58 in MVR, 30 in DVR). Operative mortality rate was 5.9%, 4.7% and 6.1%, respectively, in the three groups (overall mortality rate 5.4%). The most frequent cause of operative mortality was low cardiac output. During follow up, there were 88 anticoagulant hemorrhages (1.2%/patient-year (pt-yr)), 11 paravalvular leaks (0.2%/pt-yr), 52 thromboembolisms (0.7%/pt-yr), 60 mechanical valve thromboses (0.8%/pt-yr) and 78 reoperations (1.1%/pt-yr). These complications occurred in 101 patients after AVR, in 125 after MVR, and in 63 after DVR (4.2%, 3.7% and 4.6% per pt-yr, respectively). Patient age (p = 0.0004), concomitant surgery (p = 0.0017) and late valve-related complications (p = 0.0159) were statistically significant mortality factors after AVR. Previous surgery was a significant risk factor for operative mortality after MVR (p <0.05). Female gender (p = 0.0059) and age (p = 0.017) were significant risk factors for operative mortality after DVR (p <0.01). CONCLUSIONS: Following implantation of the St. Jude Medical mechanical heart valve prosthesis, a fixed dose of 2.5 mg/day warfarin and combined dipyridamole/aspirin provided satisfactory results in terms of thrombosis, embolism and bleeding.

Acute mechanical valve thrombosis of the St. Jude medical prosthesis.

From 1986 to 1996, 2585 patients underwent valve replacement with the St. Jude medical prosthesis. Sixty experienced mechanical valve thrombosis. Seventeen of 60 patients (28.3%) had isolated aortic valve replacements, 33 had isolated mitral valve replacements (55%), and 10 had double valve replacements (16.7%) (aortic and mitral valve replacement). All patients who underwent reoperation for mechanical valve thrombosis were functional Class III or IV. Against medical advice, systemic anticoagulation with warfarin sodium had been discontinued or used only intermittently. Thus, anticoagulant activity was not adequate. The diagnosis of thrombosis was made by clinical examination, laboratory findings, and echocardiography and cineradiography. Of the 60 patients, 9 patients died early after surgery or before discharge. Most of the deaths were attributed to low cardiac output. The overall hospital mortality was 15%. The overall 10-year actuarial survival rate was 82.8+/-1.6%. In our study, reoperation for thrombosed mechanical prosthesis was not an independent parameter determining mortality. Age was the only statistically important hospital mortality predictor. Of this group, 90% suffered mechanical valve obstruction within the first 5 years after operation. These results suggest that valve re-replacement appears to be a suitable surgical treatment for thrombosis of mechanical prosthetic valves, especially in the young. In these patients subsequent anticoagulation management is necessary.

Preservation of myocardial metabolism in acute coronary artery occlusions with retrograde coronary sinus perfusion and iloprost.

A total of 12 healthy mongrel dogs were subjected to the study. The left anterior descending artery was occluded. The occlusion was done for 15 min. At the end of this period, without removing the occlusion, the heart was retroperfused for 3 h. Then, occlusion was removed and reperfusion was supplied. Animals were divided into two equal groups. Six animals received iloprost and the other six control did not receive any additional treatment. In the iloprost group, the drug was administered into the coronary sinus. After 15 min following occlusion, iloprost was infused at a rate of 50 microg/min continuously. Cardiac output (CO), mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), heart rate (HR), pulmonary capillary wedge pressure (PCWP), right atrium pressure (RAP), myocardial oxygen extraction (MOE) and myocardial lactate extraction (MLE) parameters were examined in the two groups, before and during retroperfusion and during the reperfusion (1-4 h). Iloprost retroperfusion (50 microg/min) was started at the fifteenth minute of occlusion and continued till the end of the observation period (3 h). The measured hemodynamic data showed that the hearts treated with iloprost had satisfactory preservation of cardiac function. At the end of the reperfusion period cardiac output was 1.5 +/- 0.06 L/min in the control and 1.7 +/- 0.04 L/min in the iloprost group (P < 0.05). At the end of the reperfusion period, tumor necrosis factor level was raised significantly in the control group (P < 0.05). Myocardial lactate release was also high in the control group (P < 0.05). CPK-MB release was low in the iloprost group (P < 0.05). We conclude that retrogradely administered iloprost reduced the risk of myocardial injury and it is probable that this drug effectively distributes to the area of myocardium at risk.

Mitral valve replacement with St. Jude Medical prosthesis and low-dose anticoagulation in patients aged over 50 years.

BACKGROUND AND AIMS OF THE STUDY: These studies were designed to assess the effect of low-dose anticoagulation in elderly patients after mitral valve replacement. METHODS: Between 1986 and 1995, 250 patients aged > or = 50 years underwent isolated mitral valve replacement at the Cardiovascular Surgery Clinic of Turkiye Yuksek Ihtisas Hospital. The overall hospital mortality rate was 8%. Postoperatively, all patients received 2.5 mg/day warfarin, and 225 mg/day dypridamole and 250 mg/day aspirin following removal of mediastinal tubes. This regimen was continued indefinitely thereafter. RESULTS: Postoperatively, the mean International Normalized Ratio (INR) was 1.4 +/- 0.67 (range: 0.9 to 4.19) and mean prothrombin time 13.33 +/- 1.98 min (range: 11.7 to 21.3 min). Mean follow up was 1.42 +/- 1.2 years (range: 2 months to 8.3 years); total cumulative follow up was 322.75 patient-years (pt-yr). During follow up, six patients (1.85% per pt-yr) developed thromboembolic complications (including mechanical valve thrombosis), two (0.62% per pt-yr) developed oral anticoagulant-related bleeding, and two (0.62% per pt-yr) developed paravalvular leak. Five patients died during follow up (late mortality rate 1.2% per pt-yr). The nine-year actuarial survival rate was 93.9 +/- 4.8% for the entire group. CONCLUSIONS: Low-dose oral anticoagulation after mitral valve replacement with St. Jude Medical prosthesis in elderly patients provided satisfactory clinical results.

Iloprost added to the cardioplegic solutions improves myocardial performance.

A total of 12 mongrel dogs were divided into two equal groups. Six animals received IIoprost and the other 6 animals did not receive any additional treatment. In the Iloprost group, Iloprost was added to the cardioplegic solution (25 ng). Also, Iloprost was used (10 ng/kg/min.) 5 min. before and after cross-clamping. All cardiac output and biochemical measurements were evaluated before cross-clamp and 15 min., 1 h, and 4 h after cross-clamp. The measured dp/dt shows that the hearts treated with Iloprost preserved left ventricular function. Comparison of contractility indices between the groups revealed that contractile recovery was 59% in the control group and 71% in the Iloprost group (p < 0.05). Tumor necrosis factor (TNF) alpha level was significantly elevated in the control group (p < 0.001). Its level was 22.2 +/- 2.2 pg/mL in the control group and 13.8 +/- 1.0 pg/mL in the Iloprost group. E- and P-selectin levels were elevated in the control group (p < 0.001). ICAM-1 level was also elevated in the control group. ICAM-1 level was 17.7 +/- 1.8 ng/mL in the control group and 8.5 +/- 1.8 ng/mL in the Iloprost group. The Iloprost that was added to the cardioplegic solution and low dose administration during the pre- and post-ischemic period inhibits the toxic mediator release from endothelium-leukocyte interaction and reduces the severity of ischemia-reperfusion injury.

Comparison of the effects of enoximone and isoproterenol on protamine cardiotoxicity in anesthetized dogs.

In this study we investigated the effects of isoproterenol and enoximone on protamine cardiotoxicity because administration of protamine for heparin reversal during open heart surgery depresses left ventricular function. Eighteen mongrel dogs were entered into this study. After induction of general anesthesia and a stabilization period, a thermodilution catheter was inserted via the jugular vein. Another 2 catheters were inserted into the left ventricle and femoral artery. Heparin and protamine were used in all animals. Heparin dosage was 300 U/kg, and protamine dosage was 4.5 mg/kg. The animals were divided into 3 groups. Six animals received enoximone (5 micrograms/kg per min), 6 animals received isoproterenol (0.05 microgram/kg per min), and 6 animals received no inotropic agent. Measurements were performed before treatment, 5 min after protamine administration, and at 15-min intervals for 1 h. Cardiac output (CO), mean arterial pressure, pulmonary capillary wedge pressure, first derivative of left ventricular pressure (1 +/-) left ventricular systolic pressure, and heart rate were measured. CO was 1582 +/- 34 ml/min in the isoproterenol group (I + P), 1684 +/- 61 ml/min in the enoximone group (E + P), and 1471 +/- 37 ml/min in the protamine group (P) (p < 0.05 E + P vs I + P and P) 60 min after protamine administration. The first derivative of left ventricular pressure (dP/dt) was 1995 +/- 61 mmHg/sec in the I + P group, 2320 +/- 85 mmHg/sec in the E + P group, and 1816 +/- 48 mmHg/sec in the P group (p < 0.05 E + P vs I + P and P). In our experimental study, the isoproterenol and protamine combination did not increase hemodynamic activity. However, isoproterenol alone significantly increased hemodynamic activity as determined by dP/dt values. Protamine administration impairs the effects of beta agonists on the myocardium. In the protamine group, CO and pressure-dependent values were significantly reduced. Isoproterenol administration did not reverse this deterioration because of the loss of the beta-receptor activity. Inotropic agents acting through the beta-adrenergic system have partial effects on myocardium. Enoximone, a phosphodiesterase inhibitor, reverses deterioration of cardiac function after protamine administration because it increases myocardial function via the phosphodiesterase system.

Simplified retroperfusion system preserves the myocardial function during acute coronary artery occlusion.

It is known that coronary venous retroperfusion restores the blood flow to the ischemic myocardium, resulting in reduction of infarct size and improvement in left-ventricular pump function. In this study, we used an animal model to investigate the effects of a simplified coronary venous retroperfusion system on myocardial hemodynamics. Twenty dogs were entered in this study. All dogs underwent fifteen minutes occlusion of the left anterior descending artery. For the rest of the experiment the dogs were randomized into two groups: the control group (n = 10) underwent a further 2 hours left anterior descending artery occlusion, then clamps were released and the animals were observed for 6 hours. In the retroperfusion group (n = 10) a simple aortocoronary sinus connection was made and retrograde perfusion achieved with an outflow of 43 +/- 6 ml/min. Retrograde coronary sinus perfusion was maintained for three hours and then the dogs were observed for six hours. Tissue adenosine triphosphate levels were 6 +/- 3 mumol/g in the control group and 12 +/- 2 mumol/g in the retroperfusion group (p < 0.05) 6 hours after reperfusion. Creatine phosphokinase levels were 99 +/- 11 IU/L in the control group and 42 +/- 8 IU/L in the retroperfusion group 6 hours after reperfusion (p < 0.05). Cardiac index was 63 +/- 4 ml/kg/min in the control group and 79 +/- 2 ml/kg/min in the retroperfusion group 6 hours after retroperfusion (p < 0.05). Left-ventricular stroke-work index at a pulmonary capillary artery wedge pressure of 20 mmHg was 0.54 +/- 0.06 g.m/kg in the retroperfusion group and 0.29 +/- 0.03 g.m/kg in the control group 6 hours after reperfusion (p < 0.05). It is concluded that myocardial hemodynamic and biochemical function can be preserved by simplified coronary sinus retroperfusion.

Aortic valve replacement with the St. Jude Medical prosthesis and fixed dose anticoagulation.

Over a 10-year period, between 1986 and 1996, 865 patients underwent primary aortic valve replacement (AVR) with the St. Jude Medical mechanical prosthesis. Patients who had undergone valve replacement with a different type of prosthesis previously were excluded from this study. Patient age ranged from 11 to 79 years. The mean age was 42.9 +/- 14.54. The gender distribution was 396 men (45.8%) and 469 women (54.2%). All patients received 2.5 mg/day Coumadin after extubation. A combination of the antiaggregant therapy (Dypridamole 3X 75 mg/day, Asprine 100 mg/day) was added after removal of the chest tubes. The dosage of Coumadin was maintained constant regardless of the prothrombin time (PT) or cardiac rhythm. There were 101 valve-related complications (4.2% per patient year [ppy]) occurring in the late follow-up period. Of these complications; 38 were anticoagulant-related hemorrhage (1.58% ppy), 3 were paravalvular leak (0.12% ppy), and 36 were thromboembolism (1.4% ppy). There were 24 reoperations (0.99% ppy) and 17 late deaths. The linearized late mortality rate was 0.7% ppy. Long-term survival estimates at 5 and 10 years were 97.14 +/- 0.82% and 94.86 +/- 1.54%, respectively. We conclude from the data that the St. Jude Medical valve may allow the use of a low level of anticoagulation. This study shows that fixed dose oral anticoagulation does not increase the rate of thromboembolism in patients with the St. Jude aortic valve. This protocol does not result in reduction of bleeding complications, however.