Volume 15 - Número 3

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BACKGROUND: To analyze the hemodynamic behavior of the heart in revascularization of the myocardium without use of extracorporeal circulation. MATERIAL AND METHODS: From August 1991 to June 1999, 616 patients suffering from angina of the chest underwent revascularization of the myocardium without use of extracorporeal circulation. In 18 patients the intraoperative hemodynamic parameters were studied. RESULTS: Heart rate remained high at all times during positioning of the heart (p=0.0007). Cardiac output throughout the procedure presented a very slight variation at different moments of positioning of the heart and exposure of the coronary arteries. However, once the heart was in its final normal position a major increase in output was noted (p=0.010). Mean blood pressure was found to be decreased throughout the procedure for exposing the coronary arteries (p=0.022). Arterial pulmonary pressure proved to be reduced at all times during mobilization, but without statistical significance. Pulmonary capillary pressure showed considerable, but statistically insignificant variation during exposure of the arteries. Central venous pressure behaved in a more varied fashion during exposure of the arteries, but again without statistical significance. Systemic vascular resistance proved to be diminished throughout the procedure (p=0.0001). Pulmonary vascular resistance remained reduced at all times during the procedure (p=0.002). Stroke volume was unchanged during anastomosis of the anterior interventricular artery and statistically significant differences were observed only in the right coronary (p=0.002) and right circumflex (p=0.0006) artery and its branches. The cardiac index was shown to be diminished throughout the procedure (p=0.0011). CONCLUSIONS: A) The present technique allows for maximum mobilization of the heart without inducing hemodynamic instability. B) The improvement of a number of hemodynamic parameters at the end of the procedure may be accounted for by: (1) the response to the myocardial revascularization; (2) the release of catecholamines following manipulation of the heart in the different positions and (3) the release of vasoactive mediators following prolonged traction of the pericardium. Keywords: Myocardial revascularization, methods; Heart, physiopathology; Extracorporeal circulation; Hemodynamics; Intraoperative period

OBJECTIVE: The aim of this study is to evaluate immediate hemodynamics evolution in myocardial revascularization with intermittent aortic cross-clamping, using or not a preconditioning protocol. MATERIAL AND METHODS: Thirty-five patients underwent myocardial revascularization, they were randomized in two groups: the control group (18) with intermittent aortic-clamping, and the preconditioning group (17) with two short aortic-clamping before the onset of conventional intermittent clamping. In both groups the patients' mean arterial pressure (mAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), left ventricular stroke work index (LVSWI) were monitored before the onset of the cardiopulmonary bypass (moment 1) and the sternal suture (moment 2), and, postoperatively at six/twelve/eighteen/twenty-four hours (moments 3, 4, 5 and 6, respectively). Also the patients' left ventricular ejection fraction (LVEF) was controlled through echocardiogram, in moments 1 and 2. RESULTS: None statistical differences was seen between groups, however occurred a growth in CI and LVEF after revascularization. All patients presented good clinical evolution. CONCLUSION: The hemodynamic evolution was similar between the groups. Keywords: Myocardial revascularization; Myocardial revascularization, methods; Hemodynamics, physiology; Extracorporeal circulation; Aortic clamping; Myocardial protection; Myocardial revascularization, comparative study; Myocardial revascularization, hemodynamics

MATERIAL AND METHODS: An metabolic analyse of hypothermic retrograde continuous blood cardioplegia was done in a prospective study of 15 patients scheduled for elective CABG. Inclusions criteria were double or triple vessel coronary artery disease and preserved left ventricular function (ejection fraction > 40%). Exclusions criteria were unstable angina, insulin-treated diabetes mellitus and associated peroperative procedures. Three patients were excluded of the study (associated procedure and coronary sinus catether dislocation). Arterial and coronary sinus blood samples were simultaneouslly taken: before ECC (extracorporeal circulation), when the aortic clamp was takem off and 10, 30 and 60 minutes after reperfusion for analysing of oxygen content and lactate concentration. Four transmural left ventricular biopsies samples were obtained: before aortic clamping, immediately after the inicial cardioplegia bolus, immediately before aortic declamping and 30 minutes after reperfusion for analysing of the levels of ATP, ADP, AMP and lactate in the myocardial. The CK-MB isoenzyme was analysed in venous blood samples. RESULTS: There was no mortality in the group. There was a decrease in the arterial-venous extraction of oxygen and lactate in the heart during reperfusion, occurring a parcial recuperation only at 60 minutes of reperfusion. The ATP and the others nucleotides had their levels in the myocardium maintened during aortic clamping, but these levels decreased during the first 30 minutes of reperfusion. The lactate was accumulated in the heart muscle during aortic clamping and his levels also decreased during reperfusion. The CK-MB levels were elevated specially between the third and sixth post-operative hour. CONCLUSIONS: In the 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 parcial metabolic recuperation. These alterations were probably a reflexion of cellular ischemic injury occurred during cross-clamping and they were of transitory effect. Keywords: Myocardium, metabolism; Heart arrest induced, methods; Hypothermia induced, methods; Myocardium, drug effects; Myocardium reperfusion; Heart physiology; Myocardial revascularization

OBJECTIVE: The purpose of this study is to analyze the experience of the Heart Institute with the use of mechanical bileaflet prostheses. PATIENTS AND METHODS: Between June 1989 and August 1998, 323 mechanical bileaflet prostheses were implanted in 300 patients. Mean age was 38.7 ± 18.4 years. One hundred and ninety one (63.7%) patients were male. The ethiology was rheumatic fever in 161 (53.7%) patients. One hundred and eighty-six aortic valve replacements, 89 mitral replacements, 2 tricuspid replacements, 22 double mitral and aortic replacement and 1 mitral and tricuspid replacement were performed. Seventy -three (24.3%) patients were in NYHA functional class (FC) IV 165 (55.4%) in FC III and 61 (20.3%) in FC II. RESULTS: Hospital mortality was 9% (27 patients), 13.5% in the mitral group, 7.5% in the aortic group and 4.5% in double mitral and aortic. The linearized rates in the late postoperative period were: 0.3% patient-year for endocarditis, 0.3% patient-year for leak, 0.2% patient-year for hemorrhage and 1.0% patient-year for thromboembolism. In the late postoperative period 213 patients (91%) were in FC I, 16 (6.8%) in FC II, 4 (1.7%) in FC III and 1 (0.5%) in FC IV. The actuarial survival in 9 years was 68.1 ± 15.5% for the mitral group and 67.5 ± 10.8% for the aortic. CONCLUSIONS: In conclusion, the results of valve replacement with mechanical bileaflet prostheses were satisfactory. Keywords: Heart valve prosthesis implantation, methods; Heart valve diseases, surgery; Heart valve prosthesis implantation, mortality

OBJECTIVE: The purpose of this study was to describe a new technique for closure of patent ductus arteriosus (PDA) by minithoracotomy (2.5 a 3.0 cm) and clipping the PDA with titanium clips. MATERIAL AND METHODS: From November 1996 to December 1997, 15 children with PDA underwent surgical closure. The mean age at the time of operation was 2.7 years, mean weight was 13.9 kg. The procedure was through a left minithoracotomy at the 4o intercostal space. The ductus was identified, dissected and isolated. Interruption of ductal flow was performed by direct clipping with two clips. The chest was closed without a chest drain. Unless the patient was ventilator dependent before the closure, the child usually was extubated in the operating room. RESULTS: Color doppler echocardiography demonstrated total occlusion of the ductus in all patients. All 15 patients were discharged from the hospital on the 4º postoperative day (mean). CONCLUSION: We conclude that surgical closure of patent ductus arteriosus with minitoracotomy, without chest tube drainage can be accomplished safely and with low incidence of complications. Keywords: Thoracotomy, methods; Ductus arteriosus patent, surgery; Surgical procedures, minimally invasive

OBJECTIVE: This in vitro investigation aimed to compare the degree of myocardial preservation afforded by intermittent anterograde normothermic vs hypothermic blood cardioplegia, infused at 20 minutes intervals, in acutely ischemic rabbit hearts. METHODS: Myocardial concentration of glycogen and lactate, as well as mitochondrial respiration and left ventricular function (dP/dtmax ) were analyzed. The study was divided into two phases, one without (Phase I) and one with (Phase II) a period of reperfusion following the last dose of cardioplegia. Each phase included 4 groups. In Phase I, hearts sent for metabolic analysis immediately after being excised comprised the Control group. After being subjected to global normothermic ischemia for 20 min, hearts were sent for biochemical analysis (Ischemic group), or else received 4 doses of cardioplegia at 37° C (Normothermic group) or at 17° C (Hypothermic group) before biochemical analysis was performed. In Phase II, except for the Ischemic group, left ventricular function was assessed on a modified Langendorff apparatus preceding metabolic analysis. RESULTS: Global normothermic ischemia (Ischemic group) resulted in reduction of glycogen levels, O2 consumption during state 3 and respiratory control rate (RCR) of mitochondrial respiration, and in elevation of lactate levels. Without reperfusion (Phase I), a significant biochemical improvement was noticed after infusion of 4 doses of hypothermic cardioplegia (Hypothermic group) except for the lactate levels that remained higher than the Control group. After normothermic cardioplegia (Normothermic group) biochemical variables showed values similar to the Control group. Reperfusion (Phase II) was followed by restoration of all biochemical variables to baseline (Control group). LV function showed similar results between Control, Normothermic and Hypothermic groups. CONCLUSIONS: The intermittent antegrade infusion of blood cardioplegia at 37° C and 17° C, infused at 20 minutes intervals, produced similar biochemical and functional results in rabbit hearts submitted to a prior period (20 minutes) of acute normothermic ischemia. Keywords: Heart arrest induced, methods; Myocardium, metabolism; Heart, physiology; Myocardial ischemia, physiopathology; Ventricular function, left, physiology

Tricuspid regurgitation arising from chest trauma five years earlier was successfully corrected by valve reconstruction in a 36 year-old man. During correction a fissure of the anterior leaflet, absence of the anterior papillary muscle, chordae tendineae and tricuspid annulus dilatation were found. Tricuspid valvuloplasty was feasible using an anchored suture of the anterior leaflet fissure, artificial bovine chordae, pericardium implantation and Revuelta ring annuloplasty. There were no complications and no early or late mortality. At 22 months follow-up tricuspid valve function has remained with mild regurgitation. The patient is in good clinical condition. Keywords: Tricuspid valve insufficiency, etiology; Tricuspid valve, abnormalities; Thoracic injuries, complications; Tricuspid valve insufficiency, surgery; Tricuspid valve, surgery

The myxomas are the most frequent primary cardiac tumors. They are usually located in the left atrium but can be found in other places. This is a case report of a 71 year old patient with diagnosis of a tumor arising from the right atrium, submitted to a surgical resection of the tumor. The operation was realized and the diagnosis confirmed. Resection was successful and the procedure uneventful. Four months postoperatively a standard two-dimensional echocardiogram revealed a residual mass that seemed to arise from the inferior vena cava. He was reoperated and the myxoma originating from the inferior vena cava and extending to the interior of the right atrium was resected. At the basis of the tumor implantation, a portion of the inferior vena cave was resected. The present report shows an unusual location of the myxoma as well as the complications regarding the diagnosis and the approach to surgical treatment. Keywords: Myxoma, surgery; Heart neoplasms, surgery; Vena cava inferior; Myxoma, diagnosis; Heart neoplasms, diagnosis; Vena cava inferior, surgery

A 65-year-old man, presented with weight loss, dyspnea and recurrent pleural effusion. Cardiac evaluation showed a (3/6) diastolic rumble at the apex and accentuated 1st heart sound. Echocardiogram evaluation and hemodynamic study revealed a large mass within the left atrium (LA), suggesting a myxoma and pulmonary hypertension. Open heart surgery was performed and a large LA tumor excised, histopathology confirmed the diagnostic of myxoma. Pleural effusion has been a very rare manifestation of cardiac myxoma, that sometimes presents unspecific signs only and symptoms of chronic inflammatory disease. Keywords: Myxoma, complications; Heart neoplasms, complications; Pleural effusion, etiology; Myxoma, diagnosis; Myxoma, surgery; Heart neoplasms, diagnosis; Heart neoplasms, surgery; Pleural effusion, diagnosis; Pleural effusion, surgery

Brazilian pacemaker register (RBM) is a nationwide database to collect data about all permanent pacemaker procedures performed in Brazil. It is a task force composed of the Health Ministry, Pacemaker Companies and Medical Society. This is a survey reporting the 6th complete year of operation. From January 1st, 1999 to December 31st, 1999, 11.048 surgical procedures for permanent cardiac pacing were performed: 8141 initial implants (73.7%) and 2907 re-operations (26.3%). Single chamber pacemakers were implanted in 6779 patients (61.4%) and dual chamber in 4258 (38.6%). Only 99 atrial single chamber pacemakers were implanted (0.7%). It was possible to detect some factors that had influenced the pacing mode choice for ventricular (VVI) or dual chamber (DC) pacing: 1) the Brazilian region where the procedure was performed; 2) the age of the patient; 3) the functional class for Heart Failure (NYHA) and the preoperative EKG finding. Regional Influence: Ventricular pacemakers were more prevalent in all regions except the central-west where the DC / VVI ratio was 1.5: 1. In all other regions the VVI / DC ratio ranged from 1.3 to 2.0: 1. Age: Atrioventricular pacemakers were preferred for patients from 21 to 60 yrs. (DC / VV ratio range = 1.7:1 and 1.3:1, respectively for ages 21 to 40 and 41 to 60 yrs.). In all other age classes ventricular pacing mode was prevalent. Heart Failure: Ventricular pacemakers were the choice in classes II, III and IV (VVI / DC ratio = 1.2: 1 for class II, 1.5 : 1 for class III and 1.9: 1 in class IV). In class I patients, more dual chamber pacemakers were implanted (DC / VVI ratio = 1.4: 1). Pre-operative EKG Finding: Only sinus syndrome patients received more dual chamber pacemaker than ventricular (DC / VVI ratio = 2.1:1). In all other types of conduction disturbances, more ventricular pacemakers were implanted than dual chamber: in 2nd degree AV block the VVI / DC ratio was 1.2:1, in 3rd AB block it was 1.8: 1 and in atrial flutter / fibrillation patients 10: 1. Other Factors: Gender, preoperative symptoms and etiology of conduction disturbance were not related to pacing mode choice. Keywords: Pacemaker, artificial; Cardiac pacing, artificial, methods; Medical records, Brazil; Databases, Brazil; Pacemaker, artificial, data collection, Brazil

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