Volume 11 - Número 2

Keywords:

Keywords: Medical mistake, law aspects; Medical malpractice; Medical Ethic

OBJECTIVE: Relate the characteristics of the heart transplantation in children with complex congenital heart diseases and severe cardiomyopathies. The present article was written to show the three year experience of this procedure at the Instituto do Coração HC-FMUSP. METHODS: The methodology used was based on surgical procedure in congenital heart disease, heart transplant indication criteria, inclusion criteria for donors, postoperative management, immunosupression and prophylaxis as well as treatment for potential complications. RESULTS: From November 1992 to June 1996, fourteen children, aged 12 days old to six years of age (mean: 2.2 years), underwent transplantation. Fifty-seven percent of recipients were male; weight ranged from 3.5 to 17.8 kg (mean: 10.3 kg). The mean age of donors was 4.4 years (a range of three weeks to ten years), 80% male, weight ranging from 3.8 to 20 kg (median 14.3 kg). The survival rate was 85.7% (two deaths in 14 patients). The follow-up was between one month to three years (average 16 months). The most important complications were systemic hypertension, acute rejection and infection. The number of rejections and infections per patient were 3.5 and 3.3 episodes respectively. CONCLUSIONS: In this experience heart transplantation has been giving a chance for children with complex congenital heart diseases and cardiomyopathies, with a survival rate of 85.7%. Keywords: Heart transplantation, neonatal; Heart transplantation, pediatric

Patients with ischemic heart disease and disabling angina, for whom CABG or PTCA is impossible, present a difficult chalenge. The Transmyocardial Laser Revascularization (TMLR) provides direct perfusion of ischemic myocardium vialaser by creating transmural channels. Since April 1995 we have treated 11 patients, 9 males, mean age 68 years, with TMLR. Preoperatively 9 were in angina class IV, despite adequate and even maximum clinical medical treatment. The patients were screened preoperatively by SESTAMIBI perfusion scan and pharmacological echocardiogram to identify the location and extention of their reversible ischemia. Operative exposure was obtained via a left anterior thoracotomy. Employing a 850W CO2 laser an average of 30 was created. Bleeding from the channels was controlled by direct finger pressure and rarely by epicardial suture. The early mortality was 2 out of 11 patients. There was no late mortality. All patients revealed improvement in their clinical status, and the mean angina class was 1,8 postoperatively; In 4 patients SESTAMIBI scan was performed at the third postoperative month, and 1 showed improvement in the myocardium perfusion. Those early results indicate that TMLR is a single operative technique that may improve myocardial perfusion and provide angina relief for patients not amenable to standard methods of revascularization. However a larger number of patients and a longer time of follow-up will be needed to have definitive conclusions. Keywords: Myocardial revascularization, methods; Laser surgery, methods; Myocardial ischemia surgery; Angina pectoris, surgery; Coronary arteriosclerosis, surgery; Coronary atherosclerosis, surgery

The aim of our study is to determine the microscopical anatomy imunohistochemistry and electronical scanning analysis of the radial artery (RA); 269 patients underwent myocardial revascularization with a RA graft were studied, performing 319 RA anatomoses; 80.7% patients were male and 93.7% Caucasians. The left internal thoracic artery (LITA) was used in 246 patients at the present surgery and 17 LITA were used before (redo-operation), performing 97.8%. LITA conduits employed altogether. The patients received another additional conduits: 59 (21.9%) right internal thoracic arteries (RITA); 17 (6.3%) right gastroepiploic arteries (RGEA); 161 (59.8%) saphenous vein grafts. An average of 3.4 anastomoses/patient were constructed. There was no post-operative complications such as ischemia or infection envolving the hand with interruption of the RA supply. The RA immunohistochemistry and electronical scanning microscopy showed that the internal elastic layer is developed and the media layer presented muscular fibers sheafs surrounded by collagen fibers more than elastic fibers. The post-operative complications include respiratory distress (21 -7.8%), atrial fibrillation (21 -7.8%), and enzymatic or electrocardiographic signs (12-4.5%) of acute myocardial infarction. Six (2.2%) patients needed mechanical support with intraortic balloon pump. Early angiographic controls have been performed in 21 patients. One patient developed RA dissection during the angiographic study; in all other patients the RA patency was 100%. The overall in-hospital mortality rate was 2.2% (6 patients). Recently, different arrangements of the arterial grafts were adopted to achieve a more complete myocardial revascularization. The RA are frequently employed to sequential anastomosis with the inferior and lateral left ventricular coronaries. The RA proximal anastomosis is often performed with the LITA. Both the RGEA and the RITA are used as complementar arterial grafts. From 64 patients submitted to myocardial revascularization with RA last 3 months, 2 arterial conduits were performed in 62 (96.9%) patients, 3 arterial conduits were performed in 27 (42.2%) patients and 4 or 5 arterial conduits were performed in 8 (12.5%). Although the pedicled internal thoracic artery graft remains the primary arterial conduit for myocardial revascularization, the radial artery is an excellent additional bypass conduit. Keywords: Radial artery, transplantation; Myocardial revascularization, methods; Thoracic arteries, surgery; Aorta, surgery; Saphenous vein, surgery

There is a tendency in all fields of surgery to move towards less invasive surgical techniques in recent years. The end point of this study was to analyse the possibility of myocardial revascularization through a minimum left thoracotomy approach. From September 1995 till March 1996 we operated on 19 patients that had isolated lesion of interventricular anterior artery (IAA) and/or diagonal. The anastomoses were made by a left minor thoracotomy, opening the pleura at the 4º intercostal space. Through this incision we dissected the thoracic internal artery with ligation of only few branches. The anastomoses were performed without extracorporeal circulation, with a simple interruption of coronary blood flow. At the second postoperative day we studied the patients with angiography and transthoracic echo-Doppler, to verify patency and flow. All patients had uneventful recovery without major complications. Angiography was made in 16 out of 19 and showed patency in 13. The 3 patients with graft occlusion were reoperated on without complications. The presented technique did not involve ligation of the intercostal branches, however these branches were not demonstrated by angiography. Transthoracic Doppler showed good relationship with angiographic findings. The initial results with this technique suggest that we can have another option of minimum invasive myocardial revascularization for selected patients. Keywords: Myocardial revascularization, methods; Surgery minimally invasive, methods; Mammary arteries, surgery; Coronary vessels, surgery; Myocardial revascularization surgery

BACKGROUND: After the excelent long term results reported with the Ross operation, its use increased worldwide. OBJECTIVE: Report our initial surgical experience with this procedure. METHODS: From may/95 trough february/96, 24 patients (mean age 28.3 years) were submitted to Ross procedure with the root replacement method. Reconstrution of the right ventricular outflow tract was achieved by 17 pulmonary and 7 aortic homografts stored in nutrient-antibiotic media. All patients were submitted to angiographic and echocardiographic Doppler flow studies at the immediate postoperative period to assess ventricular function and hemodynamic performance of the homografts. Three patients with follow-up longer than 6 months had a second ecocardiographic study. RESULTS: Hospital mortality was 4%. All hospital survivors were discharged in synus rhytm and with no diastolic murmur of aortic insufficiency. Hemodynamic performance of the autografts was excellent with low peak systolic gradients (4.0 ± 1.3 mmHg by echocardiography and 2.8 ± 1.2 mmHg by cardiac catheterism). Twenty-one patients had none or trivial autograft insufficiency and two presented with mild insufficiency. None had moderate or severe regurgitation. Peak systolic gradients in the homografts were also low (3.0 ± 0.9 mmHg by echocardiography and 4,3 ± 1,4 mmHg by catheterism) and only two had mild insufficiency. There was a significant reduction in left ventricular mass in the early postoperative period. After a mean follow-up of 5,1 months (1-9 months) all patients were in NYHA functional class I and free of events. Three patients with followup periods longerthan 6 months had asecond echocardiogram which showed normal left ventricular function and mass and adequate performance of the auto and homografts. CONCLUSION: The Ross operation can be done with low operative mortality and good short term results. We believe it will be widely employed by others in our country. Keywords: Pulmonary valve, transplantation; Aortic valve, surgery; Aorta,surgery; Ross operation

Ketamine (30 mg/kg, IV) and chlorpromazine (2mg/kg, IV) were evaluated as pharmacological agents, for protection of the ischemic spinal cord in a rat model. A thirty-minute period of ischemia obtained by occlusion of the proximal descending thoracic aorta was followed by reperfusion. In 70 animals (medium weght-380g) distributed in 7 equal groups, the results regarding the complete motor and sensitivity function recovery were as follows: 1) Sham-operation: 100%; 2) Ischemia-reperfusion: 0%; 3) Ketamine, 1 minute before ischemia: 30%; 4) Ketamine, 10 minutes before ischemia: 50%; 5) Chlorpromazine, 1 minute before isquemia: 50%; 6) Chlorpromazine, 1 minute before reperfusion: 10%; 7) Ketamine+chlorpromazine, 1 minute before ischemia: 60%. Both pharmacological agents were effective in the protection of the ischemic spinal cord, as confirmed by the microscopic study. However, comparison of several groups showed statistical significant difference for groups 6 and 7, only. Perfusion of the subarachnoid space revealed excessive amounts of neuro-excitatories amino-acids, L-aspartate and L-glutamate. Keywords: Spinal cord, drug effects; Ischemia, physiopathology; Ketamine, pharmacology; Chlorpromazine, pharmacology; Spinal cord, ischemic

The restoration of the systemic vascular resistance employing methylene blue (MB) in 6 patients after cardiac surgery with and without cardiopulmonary bypass is reported. All patients presented, during the immediate postoperative period, tachycardia, oligury, good peripheral perfusion and important systemic arterial hypotension not responsible to large doses of catecholamines infusion. The hemodynamic analysis, using the Swan-Ganz thermodilution technique, showed a profile compatible with vasoplegic syndrome, with the mean index of systemic vascular resistance of 868 dyne.s.cm5, similarly to the endotoxic shock this syndrome was assumed to be caused by nitric oxide synthase stimulation and release of nitric oxide (NO), by endothelial cells. Once released, NO stimulates solube guanylate cyclase, and thereby activates the production of cyclic guanosine 3',5' monophosphate (cGMP) resulting in relaxation. Methylene blue was administered to block the NO action by inhibiting the soluble guanylate cyclase at doses of 1.5 mg/kg during one hour intravenous infusion. Systemic vascular tone restoration (IRVS = 1693 dyne.s.cm5), with normal arterial pressure and clinical performance, were effective and fast, showing MB as a pharmacological tool able to reduce morbidity and mortality of the vasoplegic syndrome. Keywords: Methylene blue, therapeutic use; Heart surgery, adverse effects; Extracorporeal circulation, adverse effects; Postoperative complications, drug therapy; Hypotension, drug therapy; Vascular resistance, drug effects

Experiments were performed in "organ chambers" to investigate if high pressures infusions of crystalloid cardioplegia effect the endothelium function of epicardic canine coronary arteries. These experiments did not show any alterations at level of receptors (dose-response curves to ACH and ADP); signal transduction/G-proteins (dose-response curve to sodium fluoride); intracellular mechanisms of the EDRF/NO release (dose-response curves to phospholipase C and calcium ionophores A23187). The smooth muscular relaxant function (dose-response curves to sodium nitroprusside and isoproterenol) and contarctions (doseresponse curves to KCI and PGF2alpha) were also preserved. These experimental observations allow the following speculative considerations: a) Should barotrauma be a phenomenon present only in damaged coronary circulation? b) All infusion were performed in no more than two or three minutes. Is cardioplegia barotrauma a phenomenon time-dependente? c) High levels of potassium could be associated with barotrauma, d) Cardioplegia barotrauma is a fancy, at least in our experimental conditions? e) Experiments in "organ chambers" study only epicardic arteries. Could barotrauma damage the microcirculation? f) The canine coronary circulation is less affeccted by high pressure than human coronaries? These data are suggestive that crystalloid moderately hyperkalemic infusions at high pressures for two or three minutes, do not impair the endothelium release of EDRF/NO of canine epicardic coronary arteries. Keywords: Heart arrest, induced, methods; Barotrauma; Endothelium vascular, drug effects; Pericardium, drug effects; Coronary vessels, drug effects; Cardioplegic solutions, pharmacology

A combined mitral reconstructive surgery and Cox-maze operation without cryoablagao was performed in a 12-year-old female patient for the correction of a rheumatic mitral insufficiency and chronic atrial fibrillation. One year postoperative the patient was assymptomatic, in sinusal rhythm and no murmurs were observed. The Doppler echocardiogram showed an important reduction of the left atrial diameter and the cardiac catheterism confirmed an effective atrial systole. Keywords: Atrial fibrillation, surgery; Mitral valve insufficiency, surgery; Rheumatic heart disease, surgery; Cox operation

Six cases of anomalous origin of the coronary arteries are reported: left arising from pulmonary artery(n=3), right arising from pulmonary artery(n=2), and 1 case of right coronary with origin in the left sinus of Valsalva. They were submited to surgical repair without mortality. The controversies on the surgical options are discussed. Keywords: Coronary vessels anomalies, surgery