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Biomedical subjects

N A Stolf

Publications and source records attributed to N A Stolf.

At least 55 records · Page 3Linked to original sources
PubMed1996

[Results of aortic stenosis surgery in patients with severe ventricular dysfunction].

PURPOSE: To study the short and long term clinical course of patients with severe aortic stenosis after surgical treatment of the valvular lesion. METHODS: Thirty survivors among 31 consecutive patients with severe left ventricular dysfunction (LVD) due to aortic stenosis (AS) were submitted to clinical and echocardiographic follow-up during a mean of 30 months after surgical treatment of the valvular lesion. Twenty five (83.3%) patients were male with a mean age of 50 years (25 to 74). Before operation the following parameters were obtained: diastolic left ventricular diameter (DLVD), shortening fraction (SF), left ventricular ejection fraction (LVEF), aortic valve area (AVA), left ventricular-aortic pressure gradient (PG) and NYHA functional class (FC). During the follow up, after the surgical procedure, FC, DLVD, LVEF and SF could be analysed and compared with previous data. RESULTS: A significant rise in SF (p = 0.001) and LVEF (p = 0.0001), as well as a decrease in DLVD (p = 0.001) were observed in the follow up. Symptoms lessened in severity in the majority of patients. Three of our patients died with progressive LVD and heart failure, after at least 36 months of follow-up. These results indicate that when operation is carried out in patients with AS and left ventricular failure, a significant improvement in left ventricular function and in symptoms takes place. Although the risk of surgical treatment is increased in this group of patients, LVD should not be considered a contraindication to the procedure. CONCLUSION: The left ventricular dysfunction is not a contraindiction for the surgical treatment of the aortic stenosis.

Adult↗
PubMed1995

Clinical and left ventricular function outcomes up to five years after dynamic cardiomyoplasty.

Improvement in congestive heart failure and left ventricular function after dynamic cardiomyoplasty has been reported in patients with severe cardiomyopathies, but the long-term effects of this procedure remain unclear. In this investigation 31 patients undergoing cardiomyoplasty for treatment of idiopathic dilated cardiomyopathy were annually investigated with radionuclide scintigraphy, Doppler echocardiography, and right-sided heart catheterization. They were in New York Heart Association functional class III or IV before the operation. No hospital deaths occurred, but one patient with progressive heart failure required urgent heart transplantation 42 days after cardiomyoplasty. The other patients were followed up from 6 to 70 months (mean 25.6 months) and 12 patients died at late follow-up. Actuarial survivals were 86% at 1 year, 61.4% at 2 years, and 42.5% at 3 to 5 years of follow-up. Multivariate analysis of factors influencing outcome showed that long-term survival was significantly affected by preoperative functional class and pulmonary vascular resistance. Functional class improved from 3.2 +/- 0.4 to 1.7 +/- 0.7 in the surviving patients (p < 0.01). Furthermore, left ventricular ejection fraction improved from 19.8% +/- 3% to 23.9% +/- 7.2% (p < 0.01), and significant changes in stroke index, arterial pressure, pulmonary wedge pressure, and left ventricular stroke work index were also found at 6 months of follow-up. In the late postoperative period, the left ventricular ejection fraction tended to decrease and returned to preoperative levels at 5 years, whereas hemodynamic variables did not change significantly. Thus, despite the tendency of the left ventricular ejection fraction to decrease at late follow-up, the long-term course of these patients seems to be characterized by the maintenance of hemodynamic improvement. However, long-term survival after cardiomyoplasty is limited by the severity of the patient's condition before the operation.

Actuarial Analysis↗
PubMed1995

Present trends in clinical experience with dynamic cardiomyoplasty.

Dynamic cardiomyoplasty has been performed to reinforce the myocardium in the treatment of patients with severe cardiomyopathies. At the Heart Institute of São Paulo University Medical School, 36 patients were submitted to cardiomyoplasty between May 1988 and December 1993. The indications were idiopathic dilated cardiomyopathy in 31, ischemic cardiomyopathy in 3, and Chagas' disease cardiomyopathy in 2 patients. Twenty-eight patients were categorized in New York Heart Association (NYHA) Class III and 8 in Class IV despite the use of maximal medical therapy. There were no hospital deaths, and patients were followed up from 2 to 70 months (mean, 24 months). Besides the improvement of NYHA functional class from 3.2 +/- 0.6 to 1.6 +/- 0.9 at 6 months of follow-up, patients also presented significant changes in the left ventricular systolic and diastolic functions. Nevertheless, 16 patients died, and 2 patients were submitted to heart transplantation during late follow-up. Actuarial survival rates were 82.3% at 1 year, 61.5% at 2 years, and 38.8% at 5 years of follow-up. Otherwise, the analysis of factors influencing the outcome showed that long-term survival was significantly affected by preoperative functional class and by pulmonary vascular resistance. The 26 patients operated in NYHA functional Class III and with pulmonary vascular resistance below 4 Wood units presented survival rates of 72.7% at 2 years and of 63% at 5 years of follow-up. In conclusion dynamic cardiomyoplasty improves functional class and left ventricular function in patients with severe cardiomyopathies. However, the long-term survival after this surgical procedure may be limited by the patients' condition before the operation.

Adolescent↗
PubMed1995

Design, manufacturing, and testing of a paracorporeal pulsatile ventricular assist device: São Paulo Heart Institute VAD.

This paper describes the design of a ventricular assist device (VAD), its manufacturing, and testing. The VAD presented is pulsatile, with a free-floating membrane, smooth internal surfaces, and pericardial valves. It comprehends also a pneumatic driving unit capable of operating in the "full to empty," EKG synchronized or asynchronous modes. In vitro tests were performed to assess its mechanical durability, hydrodynamic performance, and hemolysis. To optimize cannulas and implant techniques, we performed in vivo tests in 22 sheep and 8 calves. In these tests, we also evaluated hemolysis and the device's capacity to normalize hemodynamic parameters during induced cardiac failure. The VAD worked for 4,000 h without failure in a mock circulatory loop. In full to empty mode, it displayed a rate-mediated "Starling-like" performance. Optimum output was achieved with a systole duration of 40% of the cycle. The in vitro hemolysis index (IH) was 6.7 +/- 2.1. Hemolysis in animal experiments was clinically nonsignificant. In calves with induced cardiac failure, the VAD was able to normalize hemodynamic parameters within 120 min.

Animals↗
PubMed1995

[Evaluation of chronic morphological changes in the latissimus dorsi, after cardiomyoplasty, with magnetic resonance].

PURPOSE: Long term clinical and hemodynamic benefits of dynamic cardiomyoplasty (DC) have been reported. However, no information is available about long-term morphological changes in the wrapped latissimus dorsi (LD) muscle in humans. METHODS: The latissimus dorsi muscle flap was evaluated by magnetic resonance imaging (MRI) in 5 patients submitted to DC for treatment of severe dilated cardiomyopathy. All patients were studied from 24 to 52 months after the surgical procedure at the time of the cardiomyostimulator replacement. In the interim, LD was stimulated with burst of 6 pulses (burst duration 185 msec, burst freq 30Hz) synchronized to every cardiac contraction with a maximum of 100 LD contractions/min. Images were acquired on a GE Sigma 1.5 T system (TE = 25ms, TR = R- Rx2, slice thickness 8mm). RESULTS: The thickness of was 7.6 +/- 0.8mm. In addition, the signal intensity of the LD was compared with that of thoracic skeletal muscle and was found to be increased (2.19 +/- 0.42). The signal intensity was similar to that of subcutaneous fat in those images. CONCLUSION: Morphologic changes in the wrapped LD muscle consistent with fatty degeneration occur after DC and can be detected by MRI. Further studies will be necessary to demonstrate the clinical significance of such LD muscle flap changes.

Adult↗
PubMed1994

Unsuspected rheumatic fever carditis ending in heart transplantation.

A 25-year-old female patient with presumed peripartum cardiomyopathy was submitted after two years to orthotopic heart transplantation. Pathological examination of the excised heart revealed acute rheumatic fever. Five days after the transplantation persistent fever developed. The patient's condition deteriorated until death after six weeks, which was attributed to cytomegalovirus disease.

Adult↗
PubMed1994

Cardiomyoplasty review: physiological principles and characteristics of electrically stimulated skeletal muscle. II. A therapeutic option.

Chronic heart failure continues unsolved as ever despite recent advances in cardiac surgery and pharmacological new armamentarium and remains a significant cause of death, regardless of etiology. Cardiomyoplasty (CMP), a new form of biomechanical ventricular support, has given new life to the field of mechanical circulatory support, providing a "bridge" to transplantation and serving as a possible alternative to surgical treatment. The geographic distribution of world experience in 401 patients shows that 80% were centralized in Europe (50%) and South America (30%). This review of the data analysis, documented improved changes in patients clinical status, further clarifies and appropriate patients population indications for DCMP as well as that more than 80% survival probability for NYHA class II & III and an early procedure related mortality of 8 to 10%.

Cardiomyopathy, Dilated↗
PubMed1994

Geometric reconstruction in left ventricular aneurysm. Surgical aspects and early results.

The early results of 79 patients who underwent left ventricular aneurysmectomy with geometric and circular reconstruction in a seven-year experience are analyzed. The most common indication for operation was congestive heart failure (78.4%), either isolated (25.3%) or with angina (53.1%). Sixty patients (76%) were in NYHA class III and 10 (12.6%) in NYHA class IV at the time of surgery. Fifty-eight (73.4%) underwent coronary artery by-pass graft surgery. Hospital mortality was 5.1%, in patients older than 60 (12%), in NYHA class IV (20%), with poor left ventricular function (EF < 0.30-20% and LVED > 25) (14%), and with extensive coronary artery disease (10%) were under increased risk. Low cardiac output and use of intra-aortic balloon pump were also associated risk factors. Other risk factors mentioned in the literature are discussed. There were no deaths from isolated left ventricular aneurysmectomy. The early results of this study and the early and late results of others using the same technique are better than the results obtained in previous studies of different types of correction, suggesting that this is the procedure of choice for treating left ventricular aneurysm.

Adult↗
PubMed1994

[Design, manufacturing, and testing of a pulsatile ventricular assist device].

PURPOSE: To describe the design of a ventricular assist device (VAD), its manufacturing and testing. METHODS: The VAD is pulsatile, with a free floating membrane, smooth internal surfaces, and pericardium valves. It comprises also a pneumatic driving unit capable of operating in the "full to empty", EKG synchronized or asynchronous modes. The system was tested "in vitro" to assess its mechanical durability, hydrodynamic performance and hemolysis. "In vivo" tests were performed in 22 sheep and 8 calves aiming at optimizing cannulas and implant techniques. In these experiments, hemolysis and the device's capacity of restoring to normal hemodynamic parameters during induced cardiac failure were evaluated. RESULTS: The device was worked 4,000 hours without failure in a mock circulatory loop. Hydrodynamic performance was satisfactory for adult circulatory support. In "full to empty" mode it displayed a frequency mediated "Starling like" performance. Optimum output was achieved with a systole duration of 40% of the cycle. "In vitro" hemolysis index was 6.7 +/- 2.1. Hemolysis in animal experiments was clinically non significant. In calves under induced cardiac failure the VAD was able to normalize hemodynamic parameters within 120 minutes. CONCLUSION: This VAD is capable to circulatory assist for cardiogenic shock in conditions needed for an adult patient and the average time span anticipated for bridge to transplantation or post cardiotomy cardiogenic shock.

Animals↗
PubMed1994

[Human heart transplantation in Brazil].

PURPOSE: To analyze patients operated on in Brazil from May 1968 until June 1993. METHODS: Three patients were transplanted in the historical period of 1968 and 1969. In the modern period from 1984-1993, 380 transplants were performed in 379 patients. These patients were transplanted in 23 services in 20 hospitals. These services are in 12 cities of 11 states. The state with the larger number of patients was São Paulo with 239 transplants followed by Minas Gerais with 58. RESULTS: In this casuistry, the patients were predominantly male (81%) with age between 31 and 40 years (30%). The most frequent indication was idiopathic dilated cardiomyopathy (53.4%) followed by ischemic (26.8%) and with a special reference for the Chagas' etiology (11%). The results in 297 patients showed 48 immediate and 49 late deaths. The actuarial survival curve showed 64.7% and 47.4% respectively after one and five years. CONCLUSION: Important differences were observed in relation to the international casuistry but even so benefits were present when compared with medical treatment.

Adult↗
PubMed1994

Magnetic resonance imaging evaluation of chronic changes in latissimus dorsi cardiomyoplasty.

BACKGROUND: Long-term clinical and hemodynamic benefits of dynamic cardiomyoplasty (DC) have been reported. However, no information is available about long-term morphological changes in the wrapped latissimus dorsi (LD) muscle in humans. METHODS AND RESULTS: The LD muscle flap was evaluated by magnetic resonance imaging (MRI) in 13 patients submitted to dynamic cardiomyoplasty for treatment of severe dilated cardiomyopathy. Eight patients were studied 15 days after the surgery (group 1) and 5 patients were studied from 24 to 52 months after the surgical procedure at the time of the cardiomyostimulator replacement (group 2). In the interim, LD was stimulated with burst of 6 pulses (duration, 185 milliseconds; burst frequency, 30 Hz) synchronized to every cardiac contraction, with a maximum of 100 LD contractions per minute. Images were acquired on a GE Sigma 1.5-T system (echo time, 25 milliseconds; repetition time, R-R x 2; slice thickness, 8 mm). The thickness of the LD decreased from 19.6 +/- 7.3 mm for group 1 to 7.6 +/- 0.8 mm for group 2 (P < .01). In addition, the signal intensity of the LD was compared with that of thoracic skeletal muscle and was found to be significantly increased in group 2 (2.19 +/- 0.42) compared with group 1 (1.04 +/- 0.07, P < .001). The signal intensity for group 2 on the T1-weighted images was similar to that of subcutaneous fat in those images. CONCLUSIONS: Morphological changes in the wrapped LD muscle consistent with fatty degeneration occur after DC and can be detected by MRI. Further studies will be necessary to demonstrate the clinical significance of such LD muscle flap changes.

Adipose Tissue↗
PubMed1994

Arrhythmias and sudden death after dynamic cardiomyoplasty.

BACKGROUND: The main causes of death in patients with severe cardiomyopathy are progressive heart failure and sudden death. The influence of cardiomyoplasty on the incidence of sudden death and arrhythmias in patients with cardiomyopathy remains unclear. The aim of this study was to investigate the occurrence of arrhythmias and sudden death after cardiomyoplasty. METHODS AND RESULTS: We studied 32 patients (26 male, 6 female; mean age, 48 +/- 12 years) who submitted to cardiomyoplasty for treatment of heart failure in New York Heart Association (NYHA) class III (n = 24) or class IV (n = 8). The etiology was idiopathic dilated cardiomyopathy in 27 patients, ischemic heart disease in 3 patients, and Chagas' heart disease in 2 patients. Patients were routinely studied before and every 6 months after cardiomyoplasty by means of radioisotopic angiography and 24-hour Holter monitor recordings. There were no operative or immediate postoperative deaths. During the postoperative period, 5 patients presented with acute atrial fibrillation and 1 had an episode of sustained ventricular tachycardia. All episodes were successfully treated with intravenous antiarrhythmic drugs or cardioversion. During follow-up (from 2 to 66 months), 15 patients died from sudden death (n = 5) or progressive heart failure (n = 10). Survival rates at 1, 2, and 4 years were 79.9 +/- 7%, 62.5 +/- 9.7% and 35 +/- 12.1%, respectively. At 6-month follow-up, NYHA functional class improved from 3.2 +/- 0.4 to 1.7 +/- 0.6 (P = .001) and left ventricular ejection fraction increased from 19.8 +/- 3.3% to 24 +/- 8.2% (P = .004). The mean values per day of premature ventricular complexes (PVCs) and episodes of nonsustained ventricular tachycardia (NSVT) did not change statistically. The mean number of PVCs per 24 hours before and at 6, 12, 24, 36, and 48 months after surgery were 126 +/- 44, 96 +/- 33, 90 +/- 29, 81 +/- 35, 71 +/- 35, and 59 +/- 48. The mean number of episodes of NSVT per 24 hours before and at 6, 12, 24, 36, and 48 months after surgery were 3.3 +/- 1.3, 1.9 +/- 0.5, 1.3 +/- 0.5, 1 +/- 0.5, 1.5 +/- 1.1, and 0.6 +/- 0.5, respectively. With respect to analysis of the idiopathic dilated cardiomyopathy subgroup, there also were no significant differences in the incidences of pre- and postoperative arrhythmias. CONCLUSIONS: Despite NYHA functional class and left ventricular function improvements observed after cardiomyoplasty, the incidence of arrhythmias did not change, and sudden death was an important finding mainly in late follow-up. The problem of sudden death after cardiomyoplasty, the mechanism that produces it, and the means to prevent it remain critical areas for future research.

Arrhythmias, Cardiac↗
PubMed1994

[Dynamics of patient selection for heart transplantation or cardiomyoplasty].

PURPOSE: To evaluate patient selection for heart transplantation or dynamic cardiomyoplasty. METHODS: We evaluated 380 patients from April 1991 to July 1993. The ages ranged between 16 and 68 (mean 43.5 +/- 11.46) years, 303 (79.7%) were male. The diagnoses were dilated cardiomyopathy in 163 (42.9%), Chagas' cardiomyopathy in 70 (18.4%), ischemic heart disease in 61 (16.1%), hypertensive heart disease in 40 (10.5%), valvular heart disease in 23 (6.1%), alcoholic cardiomyopathy in 12(3.2%), peripartum cardiomyopathy in 5 (1.3%) and myocarditis of unknown etiology in 5 (1.3%). RESULTS: The indication of heart transplantation was eventually done in 55 (14.4%), and 19 (5%) were submitted to transplantation. Dynamic cardiomyoplasty was indicated in 9 (2.3%) patients and was performed in 8 (2.1%). In 30 (7.8%) patients there were clinical contraindications for transplantation. Conventional surgical treatment was indicated for 12 (3.1%) patients: myocardial revascularization and/or ventricular aneurismectomy in 5, surgical treatment of valvular heart disease in 6 and of atrial fibrillation in 1. Socioeconomic limitations precluded transplantation in 43 (11.3%) and psychic limitations hindered transplantation in 23 (6.0%) patients. Refusal of procedure by the patient occurred in 10 (2.6%) cases. Improvement of the symptoms occurred in 69 (18.1%) patients. CONCLUSION: A small percentage of patients are eligible and are eventually submitted to heart transplantation or dynamic cardiomyoplasty. New strategies may be delineated during follow up, as deferring transplantation or conventional surgical treatment of ischemic or valvular heart disease. Sociopsychic evaluation is an important step in the care of the patients.

Adolescent↗
PubMed1993

Current expectations in dynamic cardiomyoplasty.

Dynamic cardiomyoplasty has been evaluated in the treatment of severe cardiomyopathies. This report outlines the results of this procedure in 21 patients with dilated or ischemic cardiomyopathy who were in New York Heart Association class III or IV before operation. There were no operative deaths. Patients were followed up for a mean of 17.6 months. Eight patients died during late follow-up, and actuarial survival rates were 73.2% at 1 year and 65.9% at 2 years of follow-up. Functional class improvement was documented in the surviving patients. Furthermore, significant improvement in left ventricular function was demonstrated by radioisotopic angiography and by heart catheterization for more than 2 years after the operation. These studies documented that left ventricular ejection fraction increased as a result of global improvement in regional wall motion. Absence of clinical and hemodynamic improvement after cardiomyoplasty seems to be related to muscle flap ischemic compromise, whereas the patient's condition before operation seems to influence the long-term outcome of cardiomyoplasty.

Adolescent↗
PubMed1993

[Subaortic stenosis caused by anomalous chordae tendineae of the mitral valve ("mitral web")].

Patient with subaortic stenosis due to the insertion of anomalous chordae tendineae of the mitral valve in the interventricular septum (mitral web) associated with mitral stenosis with diagnosis made by bidimensional echocardiographic study with Doppler and confirmed by hemodynamic study. The patient was submitted to surgical treatment. The anomalous cords were resected and the mitral valve with severe malformation was replaced by a bioprosthesis. The patient had a uneventful recovery and echocardiographic evaluation showed an outflow tract without obstruction, with no gradient, with remnants of the papillary muscles and normo-functioning bioprosthesis.

Aortic Stenosis, Subvalvular↗