Volume 3 - Número 1

Valvar replacement with a g lutara Id eh yde-pre served, homologous aortic valve in a flexible stent is an original procedure of which we made preliminary reports. We now present up-dated information and follow-up data in a larger cohort of patients. Until now 118 patients have received the prosthesis, most oi them defined as a "high-risk" due either to age less than 15 years old or due to calcification of a previous bioprosthesis. Ages varied from 5 to 66 years (median: 20 y/o); 62 patients (52.5%) were children and 18 (15.3%) had a calcified bioprosthesis. The procedures performed were 88 isolated mitral valve replacement, 9 mitral and aortic replacement, 8 isolated aortic valve and 2 isolated tricuspid substitution. Hospital mortality was 2.5% (3/118); post-operative follow-up consisted of 2614 months/patient with complete and detailed direct follow-up obtained in 91% of survivors, Survival was 94.9%. at 36 months with only 3 deaths in the 115 patients who were discharged from hospital. In our experience and in the literature these results are superior to those with other biological prosthesis: it seems likely that this prosthesis will be highly recommended, specially for children, jf these results are maintained in longer periods. Keywords: heart valves, homologous, surgery; heart valves, surgery

Beneficial effects of cardiomyoplasty have been documented and the use of this technique in the treatment of dilated cardiomyopathy have been suggested. This study was undertaken to evaluate the contracting and fatigue characteristics of normal and conditioned Latissimus Dorsi and the effectiveness of stimulated preconditioned skeletal muscle flaps wrapped around the heart to restore ventricular contractility in presence of myocardial dysfunction. Thirteen adult mongrel dogs were studied after burst stimulation of left Latissimus Dosi for six to eight weeks. In seven animals, conditioned muscles were compared with unconditioned contralateral controls by isometric force development. Normal and transformed muscles exhibited the same optimum pacing parameters (burst frequencies from 5o Hz up, train duration from 150 ms up). Conditioned muscles showed a smaller force (-27%) and a longer contraction time (+32%). Fatigue curves of unconditioned muscles under different duty cycles showed marked initial decrease and inversely proportional stable values of force after some minutes with equal final tension time indexes (18 ± 2 KgF. seg/min). Conditioned Latissimus Dorsi maintained stable force during prolonged stimulation under same conditions with a greater tension time index (68 ± 6 KgF. seg/min). The other six animals were submited to cardiomyoplasty; hemodynamic and echocardiographic evaluation were performed after induction of myocardial dysfunction by betablockers administration and volume loading. With synchronous pulse train stimulation increases of cardiac index by an average of 36 ± 4% (p<0.01) were observed, associated with a decrease of pulmonary wedge pressure. Ejection fraction augmentation of 51 ± 3% above the control was also documented in same conditions (p<0.01), even when muscle flap was wrapped only around the left ventricle. In conclusion, this study reveals that skeletal muscles are capable to maintain steady-state work similarly to the myocardium with a power dependent of their aerobic capacity. It also suggests the occurrency of muscle adaptive transformation, increasing its steady-state work capacity, with chronic pulse train stimulation. In addition, cardiomyoplasty may be an alternative method of treatment for irreversible cardiomyopathy, including when muscle flap may wrapp only partially the heart. Keywords: cardiomyoplasty; circulatory support; myocardial insufficiency, surgery; skeletal muscle stimulation

From 1974 to December 1987, 620 patients were submitted to myocardial revascularization, with 28 deaths, 4.5% mortality. Nineteen patients received associated procedures: 14 ventricular aneurysmectomy and 5 valvular prosthesis. The method of myocardial protection was intermitent clamping of the aorta, topical and body hypothermia of 30ºC. From this experience we conclude that this method offers a satisfactory myocardial preservation. Keywords: myocardial revascularisation, surgery; myocardial preservation

Autotransfusion (AT) is an alternative to reduce the incidence of complications following homologous blood transfusion. The utilization of autogenous blood is feasible in elective surgical procedures (Pre-AT). A prospective comparative study was carried out in order to establish the ideal parameters for pre-AT, concerning volume, time interval prior to surgery and benefits to the patient, among others. Ninety-six consecutive patients candidates for myocardial revascularization, were analized in the present study. These patients did not present hypoproteinemia, anemia, infections or more than 70 years of age; cardiac reoperations were discarded. Four groups (G) were considered: GI - control group, without pre-AT (41 patients); GII - collection of 500 to 600 ml, comprizing the groups; GII-A - until 7 days before surgery (35 patients); GII-B - from 8 to 15 days before surgery (14 patients); GIII - collection of 1000 ml more than 30 days before operation, with reinfusion and a new collection after 15 days (6 patients). Mean age and hemotocrit were comparable in the different groups. In a few patients postoperative AT was utilized. The results indicated that homologous blood transfusion were necessary in 63% of GI, 26% of GII-A, 43% of GII-B and 67% of GIII patients. The mean amount of autogenous blood reinfused was 534 ml/patient in GII-A, 539 ml/patient in GII-B, and 908 ml/patient in GIII. The postoperative hematocrit at discharge from the hospital was comparable in the four groups. There were no deaths. A smaller number of patients in GII-A received homologous blood (p = 0,008) and there was no statistically significant difference in the groups II-A, II-B and III concerning the volume of homologous blood received. There was no higher incidence of complications, specially bleeding, in the different groups when compared with the control group. Keywords: autotransfusion, cardiac surgery; blood re-utilization; extracorporeal circulation, blood re-utilization

The continuity between mitral valve and the left ventricular wall through chordae tendinae and papillary muscles plays a role in left ventricular function. The morbity and mortality for mitral valve replacement remain much higher than other cardiac procedures such as aortic valve replacement, mitral valvuloplasty and coronary artery bypass grafts. These facts justify all possible studies related to the correction of mitral valve insufficiency. The present paper presents our experience with two techniques for correction of mitral valve insufficiency: valve replacement with preservation of the mitral apparatus components and valvuloplasty by the reconstruction and advancement leaflet. Our main concern was the surgical details and ventricular function studies were not performed. Various techniques to maintain continuity of the mitral valve annulus and the ventricular musculature, when valve replacements is mandatory, are presented. The importance of the reconstruction and advancement of the posterior leaflet, alone or associated with other repair techniques such as comissurotomy, annuloplasty and shortening of chordae tendinae, is emphasized. Keywords: mitral insufficiency, surgery; heart valves, surgery

In a 4 year period (1984-1987) 427 patients (313 males and 114 females, mean age 61.83 years) underwent emergency aorto-coronary bypass procedures. Indications for surgery were unstable angina, requiring intravenous nitroglycerine. 369 patients (86.41%) were class IV NYHA classification and 51.99% were grade III or IV ventricles. 30.44% had main left coronary stenosis. Mean number of grafts was 2.99%. Overall mortality was 7.72% and 17.09% had low output state. Stroke occured in 2.81% and the infarction rate was 16.86%. During the same period 30 patients (16 males and 14 females mean age 64.03 years) with unstable angina and in cardiogenic shock underwent emergency bypass. 86.66% were class IV and 13.33% class III. L. V. grade was IV 56.66% and III 13.33%. 40% had main left stenosis. Mean number of grafts was 2.75. 30% died in the OR and 30% died in 30 days. Stroke occured in 16.66% and 43.33% suffered a myocardial infartion. In conclusion the mortality and morbidity for patients undergoing emergency coronary artery bypass remain very high. This is particulary so for patients in cardiogenic shock Future developments in cardiplegic method may improve results. Keywords: myocardial revascularization, high risk patients; myocardial revascularization, surgery

Plasma catecholamine levels were measured in 20 infants (mean age 6.0 ± 5.86 months; mean weigh 5.3 ± 1.82 Kg), undergoing correction of congenital heart defects using surface cooling (26ºC), limited cardiopulmonary bypass and circulatory arrest (15ºC). Plasma adrenaline and noradrenaline were assayed in serial arterial blood samples using cromatography and electrochemical techniques. Surface cooling produced a significant rise in adrenaline and noradrenaline: the levels of both catecholamines fell, however, during core-cooling on cardiopulmonary bypass. Following the period of circulatory arrest (23/64 min, mean 41.3 min), there was a further increase in plasma catecholamines, which persisted during rewarming. Following rewarming, plasma catecholamines remained elevated untill the end of the surgical procedure. Our data show the technique of surface cooling, limited cardiopulmonary bypass and circulatory arrest produces a major sympathoadrenal response. The biological significance of high levels of circulating catecholamines under hypothermic conditions is uncertain. Keywords: simpathoadrenal function, children, surgery; surface cooling, children; cardiopulmonary bypass, children; circulatory arrest, children

The authors present the results of the utilization of Bioval bovine pericardium bioprosthesis in 73 patients operated upon in Bauru, SP. from September 1982 to December 1987. Thirty nine patients had mitral disease, 25 aortic, 6 both mitral and aortic, 2 had aortic and coronary disease and 1, mitral and coronary disease. The hospital mortality was 5.4% and none of them was valve related. There were only one patient with atrial thrombus and 1 patient with mild mitral calcification, which didn't require re-operation. Actuarial survival in 60 months follow-up was 82% for total, 88% for mitral and 78% for aortic patients. Late death was 2.7 events/100 patients/year. In conclusion, this prosthesis had a very good performance in this group of patients. Keywords: heart valves, biologic; heart valves, surgery

The authors report their experience with 14 patients who underwent correction of aneurysms of the aortic arch and descending thoracic aorta, utilizing a technique based on aortic exclusion. The approach was accomplished with an ascending abdominal aortic by-pass, and the aneurysm was isolated with a ligature of the aorta above and below it. In 5 patients, this ligature was done with staplers. Six patients died in the immediate post-operative period, mainly from preoperative clinical condition related to acute aortic dissection of the descending thoracic aorta. Severn patients have been followed from 6 months to 4 years and all of them showed a progressive reduction of the aneurysmal sac. Keywords: aneurysms, thoracic aorta, surgery