Volume 5 - Número 1

Newborns and small infants require special procedures of extracorporeal circulation for open heart surgery, which must be based on their specific physiological and metabolic patterns, as well as on the response to deviations of their homeostasis. The authors reviewed the protocols of cardiopulmonary bypass utilized during 100 procedures with total circulatory arrest and discuss some mechanisms by which the blood components may be damaged or injured during perfusion. Mechanical injury of solid blood components and plasma proteins are discussed; the activation of certain plasmatic systems as the coagulation, fibrinolytic and complement by the Hageman factor, which can produce a generalized inflammatory reaction is also identified; deviations of acid-base balance by excessive lactic acid production may impair enzymatic and cellular functions which can cause injury of a metabolic nature. Thermal injury may also be produced by overheating blood during rewarming if the dynamic nature of heat exchangers function is not adequately monitored. The conclusion is that neonatal perfusion represents a continuing exercise of attention to detail and must be performed with a profound respect to their specific physiology, metabolism and response to injury. Keywords: extracorporeal circulation, children

In acute myocardial infarction there are several treatments that try to reduce the dammage of left ventricle. The surgical treatment is one of the more important procedures after the use of thrombolitics and the complications of PCA. From July 87 to July 89, in the Instituto do Coração da Santa Casa de Ribeirão Preto, 262 myocardial revascularization surgeries were performed and 23 (8.7%) of those surgeries were during acute myocardial infarction. The patients included 19 males and 4 females. The range of age was 42 to 75 (mean: 58 yeats). The surgery was indicated for: pain, 15 (65%) cases: coronary opened by thrombolitics, 5 (22%); coronary expontaneous opened, 2 (9%) cases, and multiarterial coronary disease, 1 (4%) case. There were some factors associated with the surgery in the acute myocardial infarction: complicated TPA, 8 cases; previous use of thrombolitics, 7 cases; unsuccessful TPA, 4 cases; cardiac arrhythmia, 2 cases, and cardiogenic shock, 1 case. The localizations of the AMI were: antero wall, 14 (60.8%); posterior wall, 9 (39.2%) cases. The dammage of the myocardial wall was: transmural, 18 (78.2%) cases; subendocardial, 4 (17.3) cases, and unknown, 1 (4.3%). The range of CKMB was 15 U to 104 U (mean: 58.7 U). The left ventricle was normal in 5 cases and the other cases had variable degrees of hypocontractility. The coronary artery involved was: only lesions of the related AMI-coronary, 9 (39.1%) cases; lesion of the AMI coronary associated with lesions of other arteries, 8 (34.7%) cases; lesion of the AMI artery associated with previous myocardial infarction, 3 (13%) cases, and occluded AMI coronary associated with lesions of other arteries, 3 (13%) cases. The time of AMI surgery was 2 hours to 2 weeks (mean: 4.6 days). The relation bypass/patient was 1.7. The myocardial protection was made with discret hypothermia and crystaloid cardioplegic solution. The myocardial anoxia ranges 14 minutes to 50 minutes (mean: 16.3 minutes). The hemodynamic conditions were stable in all but 3 cases that needed inotropic drugs and longer time of assisted circulation. The postoperative follow-up shows complications in 10 (43.4%) and 3 (13%) deaths. The deaths were related with cardiac, pulmonary and neurological causes. The surgical approach in the AMI is growing up, despite os the increment of the mortality and postoperative complications. Selection of patients for operation during AMI must be individualized. Keywords: myocardial infarct, acute; myocardial infarct surgery; myocardial revascularization, surgery

Congenital diseases as pulmonary atresia, tetralogy of Fallot, among others, have been corrected using the extracardiac conduits. There is a variety of conduits valved or not that make possible the access of sanguineous flux from right ventricle to pulmonary circulation. However, the synthetic conduits with biologic or metalic valves shows prosthesis degeneration and obstruction problems and peeling of the conduit, moreover, they are very expensive. The experience with treated bovine pericardium showing it is impermeable and easy to suture, led to the production of valved conduits that in this study were evaluated for obstruction, calcification and stretching. The utilization of an animal experimental model allowed the detailed periodic evaluation by echodopplercardiography and cateterism during one, three and six months. The recuperated conduits were studied by optical microscopy and X ray, with several parts of the bioprosthesis analysed. The microscopic examination showed the conduits pericardium preserved with signs of pseudo-endotelization, and the majority of valves with moderate calcification, but with good function yet. The surgery technique without extracorporeal circulation and the results with the follow-up of five animals during six months are presented and discussed. The authors conclude that the bovine pericardium valved conduit showed good results in the right ventricule outlet, allowing to expect a satisfatory result when applied in human beings by the known relation of acelerated degeneration of the biological prostheses on the studied experimental model, several times greater than in man. Keywords: valvar tube graft, biologic

The preliminary postoperative results in 16 patients submitted to valvular replacement utilising bovine pericardial valvular bioprostheses, without resection of their natural cusps, are presented. These patients were operated on sequentially from March to September 1989. The incompetent cusps were sutured to the mitral annulus with U stitches placed at their free edges. Pre and postoperative evaluation of the following parameters were obtained: left atrial diameters, left ventricular diameters, ejection fraction and mitral transvalvular gradients (peak and mean). Statistical evaluation utilising the Student's T test was performed. Preoperative mean value of the left ventricular diameter was 67.31 mm, decreasing to 60.50 mm in the postoperative evaluation. Critical value of T was 2.131, the value observed for the left ventricle variation being 3.18. The left atrial diameter varied from 60.25 mm to 49.31 mm (T equal to 6.72). Preoperative ejection fraction mean value was 0.72 and in the postoperative was 0.65 (T = 2.68). Mean transvalvular gradients varied from 23.7 mm (peak) and 12.5 mm (mean) to 9.10 and 5.125 respectively. These residual values are acceptable according to the current literature and the experience of our Institution. There were no complications or deaths in the present series. In no patient gradients in the left ventricular out flow tract suggesting obstruction by the anterior cusp were observed. The authors consider it an efficient technique, easily and rapidly performed, without danger of atrioventricular desinsertions and without significant gradients. Ventricular performance is enhanced and the left atrial and left ventricular diameters decrease considerably. Keywords: heart valves prosteses, biologic; heart valves prostheses, surgery

Twenty patients (aged 20 to 71 years, thirteen of them females), presented recurrent and refractory nodal reentry tachycardia (NRT) and were submitted to surgical treatment. The preoperative electrophysiological studies demonstrated classical NRT. All the patients had ventricular-atrial interval of less than 40 milliseconds, and the atrial retrograde depolarization started in the anterior portion of the A-V node. Additionaly, the patients presented retrograde atrial capture phenomenon, suggesting participation of atrio-nodal or atrio-Hisian anomalous pathways. The intraoperative mapping performed during ventricular pacing demonstrate retrograde atrial depolarization starting at the posterior area of the A-V node. The surgical procedure consisted in dissection of the posterior portion of the A-V node with a similar technique used in ablation of postero-septal anomalous pathways, taking care to preserve the Todaro tendon. No intra-nor-postoperative complications were observed. The programmed stimulation performed around the 15th postoperative day was unable to induce NRT. Five to 36 months after the procedure, the patients are asymptomatic with normal A-V conduction and without use of antiarrhythmic drugs. Notwithstanding the small number of cases and the ralatively short follow-up, the surgical procedure appears efficient to control NRT, while preserving intact A-V conduction. Keywords: nodal reentry tachycardia, surgery

Between July 1981 and February 1990, 2431 patients underwent attempted percutaneous transluminal coronary angioplasty (PTCA). Seventy-nine (3.2%) patients subsequently underwent emergency miocardial revascularization, and 32 (40.5%) developed myocardial infarction with 12 (15.2%) deaths. The operative mortality rate was significantly increased among elderly patients, those with left main occlusive dissection, late coronary thrombosis, and specially among patients with hemodynamic instability after PTCA. Additional minutes or hours of low myocardial and systemic perfusion after failed PTCA also increase the risk of immediate surgical revascularization. Despite the growing role of PTCA in the treatment of more complex coronary atherosclerotic heart diseases, the number of failed procedures that necessitate coronary artery bypass surgery decreased last two years (10/1351). This have been possible by placing a reperfusion catheter (Stack) across the narrowed coronary artery lumen. Surgical results were consistently improved by modifications in myocardial protection techniques, besides the use of reperfusion catheter after failed PTCA. Keywords: myocardial revascularization, angioplasty; myocardial revascularization, surgery; myocardial protection, cardioplegia

The immunocytomonitorization technique (CIM - Cytological and Immunologic Monitoring) is based on assessment of changes in the subpopulations of lyphocyte and their precursor cells, while under the acute rejection. The method assesses the precocious activation by counting the number of the lymphocytes normal and actives, lymphoblasts and prolymphocytes (here we state in terms of a set of active lymphocytes). The technique was applied to follow-up and control of activity of cellular immunology in nine patients submitted to cardiac transplantation, twenty normal volunteers, and five patients candidates to cardiac transplantation. We also submitted to the CIM test, in order to obtain the normal range of lymphocytic activity in the brazilian population. Both groups had not antecedents, either infectious or immunological, chronic or acute pictures. Ten patients with acute bacteriological or viral infection had been tested as a positive control. In normal individuals, we found 1,8% (+/- 1.088) of active lymphocytes and 3,2% (+/0,49) in candidates for cardiac transplantation. In our experience, values above are indicators of an immunological reactivity related to infection or rejection. Out of the 63 tests performed to the cardiac transplanted patients, four of them were positive, three cases related to infectious complications and one was confirmed as a process of acute graft rejection in progress. The mean time for the CIM execution was about two hours. The method was successful for the immunological diagnosis in transplanted cardiacs, due to its sensibility, low costs and promptness of results. Keywords: immunocytomonitorization in heart transplantation; heart transplantation, human, immunocytomonitorization

Between January 1979 and December 1989, eighty five operations were performed to treat aortic dissection, including fifty in the acute phase, and thirty five in a chronic phase. The Hospital mortality was 21.1% (eighteen patients) and low cardiac output was the major cause of death. The mortality was higher in the group of patients operated upon in the acute phase. Four patients were operated upon for redissection or dissection in other localization of the aorta, and all of them died. One patient developed paraplegy in the postoperative period. The late follow-up showed good evolution in the survivors group. Keywords: aortic dissection, surgery