Volume 15 - Número 2

Keywords:

The authors report the effects of laser rays, the different kinds of rays and their interaction with biological tissues. The use of laser rays in medicine, from photocoagulation experimental studies in the animal retina to their use in atheroma plaques and the cardiac muscle is also reported, with emphasis on the pioneer studies carried out in Brazil. Indirect methods of myocardial revascularization, the basis for the use of laser rays in transmyocardial revascularization surgery are reported as well, in addition to randomized protocols which have shown this procedure is adequate for the treatment of a selected group of patients. A special emphasis is given to the kind of patient chosen for revascularization using laser, i.e., patients in end-stage coronary artery disease, with ischemic (and viable) myocardium with angina, after all the usual therapy resources have been tried, especially classic myocardial revascularization and angioplasty. The experience of the Heart Institute in a two-year period consists of 40 patients with the clinical characteristics above, who underwent transmyocardial revascularization using laser rays. After 12 months of follow-up, about 87.8% of them have a significant improvement of symptoms, with regression of class III or IV angina to classes 0, I or II (p<0.0001). Three (7.5%) early deaths and 2 late deaths were observed. Despite a mild improvement in left ventricular function, shown by magnetic resonance and echocardiographic study, there was no change in myocardial perfusion. The fate of the channels created by laser rays in the myocardium is studied based on our own results and in literature. The probable activity mechanisms are also discussed, emphasizing myocardial denervation and neoangiogenesis. Future perspective involves the use of laser in minimally invasive procedures combined to classic myocardial revascularization. Keywords: Myocardial revascularization, methods; Laser surgery, methods; Angina pectoris; Carbon dioxide, therapeutic use

BACKGROUND: CABG surgery on the beating heart (off-pump) is increasingly used to lessen injury to the brain, kidneys and other organs. However, the perioperative incidence of myocardial injury and its effect on outcome vs conventional CABG (on-pump) remains unclear. MATERIAL AND METHODS: Retrospective study of 303 patients (122 off-pump, 181 on-pump) after isolated CABG from Feb/97-Feb/99. CPK and EKG were obtained pre and post-op, MB fraction and troponin T levels were measured postoperatively. Complications were also recorded. The groups were comparable in terms of age (65 ± 10 vs 65 ± 9 yr), CCS and NYHA class. RESULTS: Mean number of grafts was 3.10 on-pump vs 2.26 off-pump. Perioperative myocardial infarction, morbidity and mortality (7/181 vs 6/122) were also comparable. There were higher postoperative CK levels in the on-pump group compared to the off-pump (548 ± 420 vs 236 ± 365). MB fraction was slightly higher in the on-pump group, but not significantly different (62 ± 197 vs 29 ± 46) nor was troponin T levels (3.5 ± 16 vs 3.5 ± 17) were An inverse correlation between the number of grafts and troponin T release in the off-pump group occurred early during our off-pump experience. There was no correlation between graft location and the incidence of infarcts or troponin T release. CONCLUSION: The higher troponin T release during our initial experience subsequently decreased. This suggests that improvements in operative technique (e.g. better exposure allowing more posterior grafts without surface trauma) may be responsible. Current techniques make off-pump CABG a safe alternative for revascularization. Keywords: Myocardium, enzimology; Myocardial revascularization, methods; Myocardial revascularization, adverse effects; Myocardial revascularization, mortality; Extracorporeal circulation, adverse effects; Extracorporeal circulation, mortality

OBJECTIVE: To evaluate the clinical and functional results of 96 patients submitted to aortic valve replacement with the pulmonary autograft. MATERIAL AND METHODS: From May/95 to March/2000, 96 patients with mean age of 25.4±11.4 years were consecutively submitted to aortic valve replacement with the pulmonary autograft. The most common preoperative diagnosis was rheumatic aortic valve insufficiency with 89% in functional class II or III. Bidimensional Doppler echocardiogram was performed in all patients and 42 were also submitted to cardiac catheterization before the operation. Pulmonary autograft was implanted as a complete root replacement in 85 patients, as a miniroot in six cases and in the subcoronary remainder position. Reconstruction of the right ventricular outflow tract was performed with pulmonary (84) or aortic homografts (12), which were stored in nutrient-antibiotic solution (34) or cryopreserved (62). Before hospital discharge, echocardiographic examination was repeated in all patients and cathterization in 30 of them in order to determine the hemodynamic performance of the auto and homografts, as well as left ventricular mass and function. During the follow-up period, patients were submitted to clinical evaluation and echocardiographic control every six months. Twenty patients with more than 6 months follow-up time were submitted to dobutamine stress echocardiography in order to determine the hemodynamic performance of the auto and homografts during exercise conditions. RESULTS: Hospital mortality was 6.2%. After a mean follow-up time of 32.1 months (1-58), 98.9% are alive. The incidence of freedom from thromboembolism, endocarditis, pulmonary autograft dysfunction, homograft dysfunction, mitral reoperations and of any kind of complications after 58 months is 100%, 100% 97.1%, 96.5%, 93.9% and 87.5% respectively. The hemodynamic performance of the pulmonary autografts was physiological, with an average mean gradient of 3.8±3.3. The degree of valvular regurgitation was negligible. Even during exercise conditions, gradients did not rise significantly, with average mean gradient of 6.8±3.8 mmHg. Hemodynamic function of the homografts was excellent during the immediate postoperative period, with average mean gradient of 4.1±4.6 mmHg. During late follow-up, however, there was a slight increase in these gradients with values of 13.9±10 mmHg. During exercise, these gradients rose significantly to 33.6±18.9 mmHg. Homograft diameter and patient age inversely correlated with late pulmonary gradients. Left ventricular mass index decreased from a preoperative value of 180±68 g/m2 to 117±32 g/m2 during late follow-up. Left ventricular mass and function was normal in the majority of patients in the late period. CONCLUSIONS: Aortic valve replacement with the pulmonary autograft was performed with a low operative mortality. Late survival was excellent, with a low incidence of complications. The hemodynamic performance of the pulmonary autografts at rest and during exercise was almost physiological. There was a significant regression of left ventricular mass and normal left ventricular function late postoperatively. Although the immediate hemodynamic performance of the right sided homografts was normal, mild gradients were frequently observed in the late period. Keywords: Aortic valve, surgery; Pulmonary valve, sugery; Cardiac surgical procedures, methods; Implantation, autologous; Cardiac surgical procedures, mortality

OBJECTIVE: To evaluate the clinical and functional results of 96 patients submitted to aortic valve replacement with the pulmonary autograft. MATERIAL AND METHODS: From May/95 to March/2000, 96 patients with mean age of 25.4±11.4 years were consecutively submitted to aortic valve replacement with the pulmonary autograft. The most common preoperative diagnosis was rheumatic aortic valve insufficiency with 89% in functional class II or III. Bidimensional Doppler echocardiogram was performed in all patients and 42 were also submitted to cardiac catheterization before the operation. Pulmonary autograft was implanted as a complete root replacement in 85 patients, as a miniroot in six cases and in the subcoronary remainder position. Reconstruction of the right ventricular outflow tract was performed with pulmonary (84) or aortic homografts (12), which were stored in nutrient-antibiotic solution (34) or cryopreserved (62). Before hospital discharge, echocardiographic examination was repeated in all patients and cathterization in 30 of them in order to determine the hemodynamic performance of the auto and homografts, as well as left ventricular mass and function. During the follow-up period, patients were submitted to clinical evaluation and echocardiographic control every six months. Twenty patients with more than 6 months follow-up time were submitted to dobutamine stress echocardiography in order to determine the hemodynamic performance of the auto and homografts during exercise conditions. RESULTS: Hospital mortality was 6.2%. After a mean follow-up time of 32.1 months (1-58), 98.9% are alive. The incidence of freedom from thromboembolism, endocarditis, pulmonary autograft dysfunction, homograft dysfunction, mitral reoperations and of any kind of complications after 58 months is 100%, 100% 97.1%, 96.5%, 93.9% and 87.5% respectively. The hemodynamic performance of the pulmonary autografts was physiological, with an average mean gradient of 3.8±3.3. The degree of valvular regurgitation was negligible. Even during exercise conditions, gradients did not rise significantly, with average mean gradient of 6.8±3.8 mmHg. Hemodynamic function of the homografts was excellent during the immediate postoperative period, with average mean gradient of 4.1±4.6 mmHg. During late follow-up, however, there was a slight increase in these gradients with values of 13.9±10 mmHg. During exercise, these gradients rose significantly to 33.6±18.9 mmHg. Homograft diameter and patient age inversely correlated with late pulmonary gradients. Left ventricular mass index decreased from a preoperative value of 180±68 g/m2 to 117±32 g/m2 during late follow-up. Left ventricular mass and function was normal in the majority of patients in the late period. CONCLUSIONS: Aortic valve replacement with the pulmonary autograft was performed with a low operative mortality. Late survival was excellent, with a low incidence of complications. The hemodynamic performance of the pulmonary autografts at rest and during exercise was almost physiological. There was a significant regression of left ventricular mass and normal left ventricular function late postoperatively. Although the immediate hemodynamic performance of the right sided homografts was normal, mild gradients were frequently observed in the late period. Keywords: Aortic valve, surgery; Pulmonary valve, sugery; Cardiac surgical procedures, methods; Implantation, autologous; Cardiac surgical procedures, mortality

INTRODUCTION: Atrial fibrillation, nowadays, has been treated surgically by the maze procedure and its modifications. However, there is some evidence that points to the pulmonary vein ostia as trigger point for this arrhythmia. We postulate a surgical approach of pulmonary vein isolation or left atrial isolation in order to treat this disease. In this study we show the initial results of this technique in patients with chronic atrial fibrillation associated with mitral valve disease. MATERIAL AND METHODS: Seven patients were operated on by pulmonary vein isolation (IVP) and compared to the past results of the 57 patients in which the maze procedure had been done (Cox 3). RESULTS: Age - 49±8 years vs. 49±11 years (IVP vs. Cox 3), 71% and 72% (IVP vs. Cox 3) were female. Left atrium size was 5.5±0.7 cm vs. 6.0±1.1 cm (IVP vs. Cox 3). Ventricular EF 63±10% vs. 64±6% (IVP vs. Cox 3). Extracorporeal circulation time 91±33 min vs.104±29 min (IVP vs. Cox 3). Aortic cross-clamping 71±23 min vs. 83±26 min (IVP vs. Cox 3). Cardiac rhythm: sinusal / atrial n(%): 6(86) vs. 46(80) (IVP vs. Cox 3). Cardiac pace rhythm n(%):1 (14) vs. 4 (7) (IVP vs. Cox 3). Atrial fibrillation n(%):0 vs. 7 (13) (IVP vs. Cox 3). CONCLUSIONS: The initial results show sinus rhythm restoration and its maintenance. We have already started a double-blind randomized trial between these two surgical techniques. Keywords: Atrial fibrillation, surgery; Atrial fibrillation, etiology; Mitral valve, pathology; Mitral valve, surgery; Cardiac surgical procedures, methods; Pulmonary veins, surgery

OBJECTIVES: Evaluate residual pressure gradients after aortic valve replacement surgery in our Institution. MATERIAL AND METHODS: Between January 1988 and December 1998, 44 patients with isolated aortic stenosis underwent surgery and received a valve prosthesis size 23 or smaller. Echocardiographic studies were performed at our Institution before surgery and six months postoperatively. There were 28(63.6%) males, with an average age of 53.9, and an average body surface area of 1.67 m2. Preoperative average transvalvar pressure gradient was 95.8 mmHg. Twelve patients were in functional class II, 28 in class III, and 4 in class IV. Bioprostheses were implanted in 25 patients, and mechanic prostheses in the other 19, 11 of which received a bileaflet prostheses. RESULTS: Six months after surgery 35 (79.5%) patients were in functional class I, and 9 (20.5%) in class II. Average gradient variation was 62.9 mmHg. The average residual postoperative gradient was 32.9 mmHg. The gradient reduction was not influenced by sex, age, body surface area, or size of the valve prosthesis. The gradient variation was directly proportional to the preoperative gradient. Regarding type of valve prosthesis, the average residual gradient was 24.3 mmHg for the bileaflet mechanical prosthesis, 33.7 mmHg for the bioprosthesis, and 42.3 mmHg for the single leaflet mechanical prosthesis. CONCLUSION: Gradient variation was directly influenced by the preoperative gradient. The best results regarding residual gradients were achieved with bileaflet mechanical prostheses, followed by bioprostheses and single leaflet mechanical prostheses. Use of a smaller than recommended for body surface area prosthesis, avoiding aortic annulus enlargement procedures, was not related to higher residual gradients in this group of patients. Keywords: Aortic valve, surgery; Aortic valve, physiology; Aortic valve stenosis, surgery; Heart valve prosthesis, implantation

OBJECTIVE: To analysis of morbidity and mortality of surgical treatment of the classic of tetralogy of Fallot in the first year of life and particularly to define possible advantages of early primary repair. MATERIAL AND METHODS: Between March 1986 and September 1999, 56 children under one age tetralogy of Fallot underwent surgical treatment. Thirty-six (64.3%) were male and 20 (35.7%) female, ranging in age from 1 to 11 months (mean 6.5 ± 2.9 mo.). Weight ranged from 3 to 10 kg (mean 6.3 ± 1.8 kg). The patients were divided into 2 groups: Group I, consisted of 26 children operated on between 1986 and 1996, submitted to a Blalock-Taussig shunt; Group II, comprised of 30 children operated on consecutively since 1996 and submitted to intracardiac repair. RESULTS: In Group I, there were 2 (7.6%) early and 1 (3.8%) late deaths. No postoperative com-plications were observed in the remaining children. In Group II, 2 (6.6%) early deaths and 1 (3.3%) non-cardiac late death of a have occurred. Only 2 children had non-significant postoperative complications and 16 presented signs of congestive heart failure. The mortality in both groups was not statistically significant. CONCLUSIONS: In the authors' experience, ideal management of children with classical Fallot's tetralogy in the first year of life consists of the intracardiac repair since it has the same surgical risk as palliation. Keywords: Tetralogy of Fallot, surgery; Cardiac surgical procedures, pediatric

BACKGROUND: As the advance of minimally invasive surgical techniques becomes more apparent, new applications are being identified. The present report describes the videothoracoscopy technique for closure of patent ductus arteriosus (PDA). OBJECTIVE: To report our initial surgical experience with this procedure. METHODS: From March 1994 to November 1999, thoracoscopic closure of PDA was performed in 40 patients, males and females, whose age ranged from 8 months to 17 years, and whose mean weight was 15 kg. After induction of general anesthesia and intubation, the patient was positioned on right side, as for a posterolateral thoracostomy. Four thoracostomies of 3 to 5 mm long were made in the left hemithorax, each corresponding in size to the appropriate instruments for work, than the PDA was dissected up and double clipped with titanium clips or closed by a thick suture with intracorporeal knot. RESULT: Three patients required conversion to thoracotomy owing to bleeding (7.5%). There was no operative mortality and the mean hospital stay was 48 hours. CONCLUSION: This is a safe procedure, with low complication rate and low cost. Keywords: Cardiac surgical procedures, methods; Arterial channel, surgery; Thoracoscopy, methods; Surgery minimally invasive, methods

OBJECTIVE: Warm intermittent blood cardioplegia has been shown to prevent the reperfusion damage seen when cold blood cardioplegia is used in patients undergoing coronary revascularization. Little is known on the effects of these two cardioplegic techniques on hypertrophic hearts. The aim of this study was to investigate the comparative effects of cold and warm antegrade blood cardioplegia in patients with aortic stenosis who underwent aortic valve replacement. MATERIAL AND METHODS: The intracellular concentration of substrates (ATP, lactate and amino acids) was measured in left ventricular biopsies taken from 20 patients undergoing aortic valve replacement in whom myocardial protection was achieved by hyperkalaemic intermittent warm (n=10) or cold (n=10) blood cardioplegia. Biopsies were taken 5 minutes after institution of cardiopulmonary bypass (control), after 30 minutes of ischaemic arrest and 20 minutes after reperfusion. RESULTS: There were no significant changes in the intracellular concentration of substrates in the samples collected during the time of ischaemic arrest when compared to control. Upon reperfusion however there was a significant fall in the ATP and amino acids regardless of the cardioplegia technique used. CONCLUSION: The data suggest that both cardioplegia techniques do not confer adequate myocardial protection in hypertrophic hearts. Keywords: Heart arrest, induced; Cardioplegic solutions; Aortic valve, surgery; Myocardial pathology; Myocardial physiology; Hypothermia, induced

We are currently studying an intraventricular axial flow blood pump in vitro. It is designed for long term left ventricular support. The small (30 cc, 7 cm length) was capable of producing flows of 5 - 8 l/min on a 8 W motor, with no device related hemolysis throughout the 12 h of the study. The cost of production, except for the batteries, has been estimated at between 5 - 8 thousand dollars, a reasonable amount for routine clinical use in Brazil. Keywords: Heart assist devices; Assisted circulation, device

INTRODUCTION: Pulmonary thromboendarterectomy is a well established method to alleviate pulmonary hypertension in cases of chronic pulmonary thromboembolism. It is difficult to balance the relatively short time of total hypothermic circulatory arrest (TCA) and the thorough opening of the pulmonary artery, and there is risk of neurologic damages. MATERIAL AND METHODS: From March 1998 to April 1999 (13 months), 8 patients, 5 male, 1 black with ages ranging from 25 to 56 years (mean: 46.2 years) with angiographic diagnosis of pulmonary thromboembolism, underwent unilateral or bilateral thromboendarterectomy for chronic pulmonary thromboembolism (PTE). Once the extracorporeal circulation is prepared and the pulmonary artery is incised, TCA is carried out and, approximately 20 minutes after thromboendarterectomy blood flow is re-established by ECC at 14o C for a period of 15 minutes for cerebral and corporeal reperfusion. Successive total circulatory arrests are carried out as many times as required until all thrombi are removed from the pulmonary artery. RESULTS: No trans-operative deaths were recorded. One patient died on postoperative (PO) day 30 due to bronchopneumonia which developed into sepsis. The 8 patients underwent hypothermic ECC and TCA, four TCA procedures were required in 5 (62.5%) and, only 3 in three (37.5%) with a mean of 3.6 TCA procedures. Total ECC time ranged from 210 to 255 minutes (mean time 225 minutes). Hypothermic TCA time ranged from 58 to 88 minutes (mean time 76.7 minutes) and the TCA time per patient ranged from 18 to 24 minutes (mean time 20.5 minutes). Skull CT scans were carried out for all patients and did not show any anatomic changes, the physical examination did now show motor deficit or sensorial loss. CONCLUSIONS: We believe this is a very promising technique which provides better operating conditions for the surgeons and central nervous system protection for the patient. Keywords: Endarterectomy, methods; Pulmonary embolism, surgery; Brain, physiology; Central nervous system diseases, prevention and control; Hypothermia, induced; Heart arrest, induced, methods

From March 1985 to September 1999, 214 patients were submitted to cardiac transplantation in consequence of refractory cardiomyopathy to medical therapy. Two patients (0.9%) aged 33 and 49 years, had developed thoracic aortic dissection as fatal late complication after the orthotopic cardiac transplantation. In the first patient suffering from idiopathic cardiomyopathy this complication occurred in the 93rd month of evolution, while in the second, with ischemic cardiomyopathy, the occurrence was early, in the 11th month. Systemic arterial hypertension and a smoking history had been showed as factors of risk in both cases. The clinical manifestations of the dissection had occurred of acute form and catastrophic that had prevented any surgical management. Greater attention of this rare complication can affect its bad natural evolution. Keywords: Heart transplantation; Heart transplantation, adverse effects; Cardiomyopathies; Cardiomyopathies, adverse effects; Aorta, dissection, risk factors

A 19 years-old-female with primary right atrial angiosarcoma partially obstructing the tricuspid valve, developed severe hypoxemia due-to-right to left shunting through a patent foramen ovale. This is the first report of such a clinical situation with this type of tumor. A complete resection of the tumor was attempted, and the right atrium had to be rebuilt with a bovine pericardial patch. Postoperative cranial, thoracic and abdominal CT scans and bone scintigraphy did not show metastatic spread. Chest radiation therapy was started on the third postoperative week. Chemotherapy was not used. The patient died a few months after surgery due to disseminated metastatic disease but no evidence of the tumor was found in the necroscopic study of the heart. Keywords: Hemangiosarcoma, surgery; Heart neoplasms, surgery; Heart atrium, surgery