Vollmer Bomfim

High early patency of saphenous vein graft for coronary artery bypass harvested with surrounding tissue

BACKGROUND Surgical trauma to the saphenous vein, used as a conduit for coronary artery bypass grafting, affects their occlusion rate. This study evaluates the early patency of saphenous vein grafts harvested with a pedicle of surrounding tissue that protects the vein from spasm and trauma. METHODS Fifty-two patients underwent coronary artery bypass grafting with saphenous veins harvested with surrounding tissue. Forty-five patients, who received a total of 124 vein grafts and 42 left internal mammary arteries, underwent angiographic follow-up at a mean of 18 months (9 to 24 months). RESULTS Patency for saphenous vein grafts was 95.4% and for left internal mammary arteries, it was 93.3%. Twenty-nine of 30 (96.7%) vein grafts anastomosed to arteries 2.0 mm or more, 65 of 67 (97%) grafts to 1.5 mm, and 10 of 13 (77%) anastomosed to 1-mm arteries were patent. Nineteen of 22 (86.4%) vein grafts with flow rates 20 mL/min or less, 32 of 34 (94.1%) with flow between 20 and 40 mL/min, and 50 of 51 (98%) with flow more than 40 mL/min were patent. Other registered surgical and clinical factors did not contribute to vessel occlusion. CONCLUSIONS Early patency rate of saphenous veins harvested with surrounding tissue is very high, even in saphenous vein grafts demonstrating low blood flow. Preservation of graft endothelium using our harvesting technique may be the explanation of this success.

Myocardial Protection During Aortic Valve Replacement: Cardiac Metabolism and Enzyme Release Following Continuous Blood Cardioplegia

Cardiac metabolism following hypothermic potassium cardioplegia with blood as cardioplegia vehicle was studied in two groups of patients undergoing aortic valve replacement. In 15 patients, blood was given as single dose infusion (single dose group) and in 18 patients the same initial bolus was followed by a continuous perfusion (25-30 ml/min) with modified blood from the heart-lung machine (continuous blood group). Simultaneous samples were drawn from arterial and coronary sinus blood before and during the first 60 min after cardioplegia. In the continuous blood group, samples were also drawn during the period of cardioplegic perfusion. The samples were analyzed for PO 2, O2-saturation and content, PCO2, pH, lactate, pyruvate, glucose, potassium, myoglobin, creatine kinase (CK), its isoenzyme MB, and aspartate aminotransferase (ASAT). In addition myoglobin and enzymes were followed in peripheral venous blood for 24 hours. Myocardial biopsies were taken from the left ventricle at the beginning and end of cardioplegia and analyzed for adenosine triphosphate (ATP), creatine (C) and creatinephosphate (CP). The pattern of metabolic changes after cardioplegia was similar in both groups with decreased myocardial oxygen extraction, marked lactate and potassium release, increased glucose uptake and significant enzyme and myoglobin release. However, the degree of changes was significantly smaller in the continuous blood group. The myocardial biopsies also showed significantly less ATP and CP decrease in the continuous blood group, suggesting, together with the other metabolic results, that the myocardial protection afforded by continuous blood cardioplegia was superior to that of the single dose group. Furthermore, continuous perfusion permitted easy control of myocardial temperature during the period of aortic cross-clamping.

Myocardial Protection During Aortic Valve Replacement. Cardiac Metabolism and Enzyme Release Following Hypothermic Cardioplegia

Cardiac metabolism following hypothermic potassium cardioplegia was studied in 23 patients undergoing isolated aortic valve replacement. All had normal coronary arteries. Cardioplegia was induced by infusing 700-1 000 ml of cold Ringers acetate containing 20 mekv K+ selectively into the left coronary artery. Simultaneous blood samples were taken from the radial artery, a central vein and from the coronary sinus before and after cardioplegia. The PO2, O2-saturation and content, PCO2, pH, lactate, glucose, potassium, myoglobin, total creatine kinase (CK), its isoenzyme CK-MB, aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) were assessed. Before bypass lactate was extracted by the heart. During the initial 10 to 20 min after cardioplegia there was a marked release of lactate in the coronary sinus. Myoglobin concentration and CK-MB serum activity peaked during the first 4 hours after the release of the aortic cross-clamping. In order to determine the best indicator of myocardial damage after cardioplegia, duration of extracorporeal circulation (ECC-time), aortic occlusion time (AOT), mean myocardial temperature (MMT) and the product of AOT and MMT, referred to as time-temperature area (TTA), were related to possible indicators of myocardial injury, such as enzyme and myoglobin release. The TTA was the best way of expressing the degree of exposure of the heart to ischaemia. The CK-MB to peak area (CK-MB max area) was the best indicator of the degree of ischaemic injury sustained by the heart during operation.

Optimal Insertion Technique for the Björk-Shiley Valve in the Narrow Aortic Ostium

The Björk-Shiley tilting disc valve was used for aortic valve replacement (AVR) in 250 consecutive patients between 1977 and 1982. One hundred and ninety-six patients had isolated AVR, and 54 had combined procedures (double- or triple-valve replacement in 31, associated coronary artery bypass grafting in 20, and miscellaneous procedures in 3). A special technique for inserting large Björk-Shiley valves without using outflow patches or annuloplastic procedures was developed. This method included allowing the right portion of the aortic incision to end about 0.5 cm above the noncoronary sinus; the use of simple interrupted sutures; placement of the prosthetic sewing ring on top of the annulus of the noncoronary sinus, thereby tilting the valve slightly in the outflow tract; and routine orientation of the major opening of the valve toward the annulus of the noncoronary sinus. This orientation resulted in the largest effective orifice area at postoperative catheterization. None of the male patients received a valve smaller than 23 mm, and none of the female patients were given a valve smaller than 21 mm. The convexoconcave model of the Björk-Shiley valve was used in 71% of the patients. An outflow patch was required only in 1 patient with concomitant supravalvular stenosis of the aorta. The combination of adequate myocardial protection, comparatively short aortic cross-clamping times, and the use of large, properly oriented Björk-Shiley valves resulted in satisfactory postoperative hemodynamics in all patients. In fact, none of the 196 patients undergoing isolated AVR and only 5 (9%) of the 54 patients undergoing combined procedures required postoperative inotropic stimulation. There were no operative deaths, and all patients left the hospital in good condition. The Björk-Shiley tilting disc valve is a reliable and well-functioning aortic valve substitute that is particularly suited for patients with narrow aortic ostia. With attention to certain details in the insertion technique, encouraging clinical results can be obtained with this prosthesis.

Sickle cell anemia and mitral valve replacement: Case Report

An 8-year-old black boy with sickle cell disease and severe hemolytic anemia crisis (95% hemoglobin S) also had mitral incompetence due to rheumatic valve disease. A 27 mm monostrut Björk-Shiley valve prosthesis was implanted after partial exchange transfusions had reduced the hemoglobin S to less than 40%. High-flow normothermic perfusion was used during extracorporeal circulation, with care taken to avoid hypoxia and acidosis. Postoperative recovery was uneventful.

Myocardial Protection During Aortic Valve Replacement: Effects of Mannitol in the Cardioplegia Solution on Cardiac Metabolism and Enzyme Release

Myocardial substrate metabolism and enzyme release following hypothermic potassium cardioplegia with and without the addition of mannitol in the cardioplegic solution were studied in two series of patients undergoing isolated aortic valve replacement. Measurements were made of PO2. O2-saturation and content, PCO2, pH, glucose, lactate, pyruvate, potassium, myoglobin, creatine kinase (CK), its isoenzyme MB and aspartate aminotransferase (ASAT) simultaneously in arterial and coronary sinus blood before cardioplegia and during the first 60 min after the release of aortic cross-clamping. In addition, myoglobin and enzymes were followed in peripheral venous blood for 72 hours after cardioplegia. Analysis of the results revealed no striking difference between the groups. Nevertheless, with the addition of mannitol, there was a slightly lower release of lactate and myoglobin probably indicating a more rapid metabolic recovery of the myocardium.

Metabolismo miocárdico após cardioplegia sangüínea hipotérmica retrógrada contínua

CASUISTICA E METODOS: Realizamos uma analise metabolica da cardioplegia sanguinea hipotermica retrograda continua em um estudo prospectivo de 15 pacientes consecutivos encaminhados para operacao eletiva de revascularizacao miocardica. Os criterios de inclusao foram doenca coronaria bi ou triarterial e funcao ventricular preservada (FE > 40%). Os criterios de exclusao foram angina instavel, diabeticos insulino-dependentes e operacoes associadas. Tres pacientes foram excluidos do trabalho (operacao associada e deslocamento do cateter de cardioplegia retrograda). Amostras de sangue arterial e do seio coronario foram simultaneamente colhidas: antes do inicio da CEC, na abertura da aorta e com 10, 30 e 60 minutos de reperfusao, para analise do conteudo de oxigenio e da concentracao de lactato. Quatro biopsias miocardicas foram obtidas do apice do ventriculo esquerdo: (1) apos instalacao da CEC (mas antes do pincamento aortico), (2) imediatamente apos o termino da inducao cardioplegica, (3) antes do despincamento aortico e (4) com 30 minutos de reperfusao, para analise dos niveis de ATP, ADP, AMP e lactato no miocardio. A isoenzima CK-MB foi analisada no sangue venoso. RESULTADOS: Nao houve mortalidade no grupo. Houve uma diminuicao da extracao arterio-venosa do lactato e do oxigenio pelo coracao durante a reperfusao, somente havendo uma recuperacao parcial ao final de 60 minutos de reperfusao. O ATP e os outros nucleotideos tiveram os seus niveis mantidos no miocardio durante o pincamento aortico, mas estes cairam nos primeiros 30 minutos de reperfusao. O lactato acumulou-se no musculo cardiaco durante o pincamento aortico e diminuiu durante a reperfusao. Houve um aumento da enzima CK-MB, principalmente entre a terceira e sexta horas de pos-operatorio. CONCLUSOES: Do ponto de vista metabolico, o metodo nao evitou o metabolismo anaerobico durante o periodo de pincamento aortico e que somente com 60 minutos de reperfusao houve uma recuperacao metabolica parcial. Essas alteracoes sao, provavelmente, o reflexo da injuria isquemica celular ocorrida durante o pincamento aortico e sao de efeito transitorio.

Myocardial Protection During Aortic Valve Replacement: Comparison Between Sanguineous and Asanguineous Cardioplegic Solutions

Myocardial substrate metabolism and enzyme release following hypothermic potassium cardioplegia were studied in two series of patients undergoing isolated aortic valve replacement. In 15 patients blood was used as cardioplegia vehicle (blood cardioplegia group) and a plain electrolyte solution was used in a control group of 17 patients. Simultaneous blood samples were drawn from arterial and coronary sinus blood before and during the first 60 min after release of aortic cross-clamping. Blood samples were analyzed for PO2. O2-saturation and content, PCO2, pH, lactate, pyruvate, glucose, potassium, myoglobin, creatine kinase (CK), its isoenzyme MB and aspartate aminotransferase (ASAT). In addition, myoglobin and enzymes were followed in peripheral venous blood for 48 hours. The pattern of metabolic changes after cardioplegia was similar in both groups, but some differences were encountered in the degree of the changes in potassium, myoglobin and CK-MB between the groups. The differences were nevertheless small and cell damage was probably of reversible nature in all patients, but the myocardial protection afforded by single dose blood cardioplegia was not unquestionably better than that of the control group.

Metabolismo miocárdico após cardioplegia sangüínea hipotérmica retrógrada contínua com indução anterógrada normotérmica

OBJECTIVE: To determinate the alterations suffering by myocardium in the hypothermic retrograde continuous blood cardioplegia with antegrade warm cardioplegic induction. METHOD: A metabolic analysis of hypothermic retrograde continuous blood cardioplegia with antegrade warm cardioplegic induction was performed in a prospective study of 15 patients scheduled for elective coronary artery bypass grafting. Arterial and coronary sinus blood samples were simultaneously taken: before establishing cardiopulmonary bypass, after anterograde warm cardioplegic induction, when the aortic clamp was removed and 10, 30 and 60 minutes after reperfusion to analyze the oxygen content and lactate concentration. Four transmural left ventricular biopsy samples were obtained: before aortic clamping, immediately after the initial cardioplegia bolus, immediately before aortic declamping and 30 minutes after reperfusion to analyze the levels of ATP, ADP, AMP and lactate in the myocardium. The CK-MB isoenzyme was analysed in venous blood samples. RESULTS: There were no mortalities in the group. Inotropic support was not necessary in any patients and no peri- or post-operative myocardial infarction was detected. There was a decrease in the arterial-venous extraction of oxygen and lactate in the heart during reperfusion, a partial recovery occurred at 60 minutes of reperfusion. The levels of ATP and the other nucleotides in the myocardium were maintained during aortic clamping, but these levels decreased during the first 30 minutes of reperfusion. The lactate accumulated in the heart muscle during aortic clamping with a decrease occurring during reperfusion. CONCLUSIONS: From a metabolic point of view the method could not avoid an anaerobic metabolism during cross-clamping and only after 60 minutes of reperfusion there was a satisfactory metabolic recovery. These alterations are probably a reflection of cellular ischemic injury that occurs during cross-clamping and they seem to be of transitory effect. A better myocardium protection was observed with the addiction of anterograde warm induction cardioplegia.

Mitral Mechanical Valve Without Long-Term Anticoagulation: Eight-year Follow-up

In 12 patients with sinus rhythm (including 5 children and 6 young women), mitral valve replacement was performed with a microporous-surfaced valve similar to the Björk-Shiley Monostrut. After the first 3 months, permitting endothelialization of the suture ring to continue over the groove and adjacent metal valve ring, no long-term anticoagulant treatment was given. There was no thromboembolic complication in this group during follow-up for 6-8 years, during which four women gave birth to a total of seven children. In eight other cases, one mitral case with atrial fibrillation, anti-coagulant was not discontinued, and in the remaining aortic cases it was reinstituted. One of them (with atrial fibrillation) had hematuria during inadequate anticoagulant medication, but no thromboembolism. Of five patients with only aortic valve replacement, two had thromboembolic complications, one without residual symptoms and one with slight hand weakness. Another had a transient ischemic attack while on anticoagulant and acetylsalicylic acid was added. Two patients with aortic and mitral valve replacement died, one from heart tamponade and the other from venous thrombosis with pulmonary embolism.