Iseu Affonso da Costa

Estudo comparativo da eficácia do etanol e do ácido L-glutâmico na prevenção da calcificação das cúspides e parede aórtica porcina: estudo experimental em ratos

INTRODUCTION: The glutataldehyde (GDA) treated pigs cusps are one of most employed tissues in bioprosthesis, but is late post-implant calcification is main cause of its failure. BACKGROUND: This study aims at comparing and analyzing two methods (ethanol 80% and l-glutamic acid 0.8%) to prevent calcification in pig cusps and aortic wall implanted subcutaneously in rats, the cusps and aortic wall segments of the control were in glutaraldehyde (GDA), during a 15, 30 and 60 days period after the implant. MATERIAL AND METHODS: We used 45 young rats, distributed in 3 groups of 15 rats each, which in turn were subdivided in 3 subgroups of 5 rats each, in which we implanted one cusp and one aortic wall segment in 2 subcutaneous pouches for each rat. We called each group as follows: GDA (control group), E80% (the group whose structures were previously prepared with ethanol 80%) and GA 0.8% (group previously prepared with L-glutamic acid 0.8%); in those groups we measured calcium and performed a microscopic analysis seeking for any calcification, its location and intensity; inflammatory infiltrate, location and type, during a 15, 30, and 60-day period after the implant. RESULTS: Calcium was found in the aortic cusp in the E80% group (1.30±0.21 mg calcium/mg tissue) at day 15, (1.05±0.22 mg calcium/mg tissue) at day 30, and (0.53±0.42 mg calcium/mg tissue) at day 60; in the GA 0.8% group (12.17±0.66 mg calcium/mg tissue) at day 15, (15.31±2.82 mg calcium/mg tissue) at day 30, and (34.24±16.28 mg calcium/mg tissue) at day 60; and in the control group, GDA at day 15 (12.44±2.26 mg calcium/mg tissue), at day 30 (13.44±3.34 mg calcium/mg tissue), and at day 60 (50.85±8.71 µg calcium/mg tissue). As for the calcium measured in the aortic wall, in the E80% group we found (4.62±0.68 µg calcium/mg tissue) at day 15, (9.47±2.59 µg calcium/mg tissue) at day 30, and (23.56±7.75 µg calcium/mg tissue) at day 60; in the GA 0.8% group at day 15 (4.31±0.85 µg calcium/mg tissue), at day 30 (7.69±1.48 µg calcium/mg tissue), and at day 60 (20.50±1.22 µg calcium/mg tissue); and in the control group (GDA) at day 15 (7.34±1.32 µg calcium/mg tissue), at day 30 (9.28±0.76 µg calcium/mg tissue), at day 60 (27.60±1.08 µg calcium/mg tissue). Microscopic evaluation of the aortic cusp, showed a progressive calcification in those fixed with GDA. Such process was found partially in the GA 0.8% group, and totally absent in the E80% group. As for the assessment of the aortic wall segments, we also observed progressive calcification, which was not inhibited by the treatment with either GA 0.8% or E80%. CONCLUSIONS: We concluded that a pre-treatment with ethanol at 80% inhibited calcification in pig aortic cusps, however it was not as effective on the aortic wall. However, L-glutamic acid at 0.8% did show that it minimizes calcification in the aortic wall. Further studies are required, to evidence if the anti-calcifying action of ethanol 80% is kept if the pig aortic bioprostheses are implanted in the circulatory system.

Valvas cardíacas obtidas por engenharia de tecidos: a mais nova geração de próteses biológicas

Hospital Charite, Universidade Humboldt, Berlim, Alemanha e Santa Casa deMisericordia, Pontificia Universidade Catolica do Parana, CuritibaCorrespondencia: Francisco Diniz Affonso da Costa – Rua Henrique Coelho Neto, 5582200-120 – Curitiba, PR – E-mail: fcosta@mps.com.brRecebido para publicacao em 12/11/01Aceito em 18/2/02

Cinco anos de experiência com a operação de Ross: o que aprendemos?

OBJETIVO: Analisar a evolucao clinica e funcional de 96 pacientes submetidos a substituicao da valva aortica por auto-enxerto pulmonar. CASUISTICA E METODOS: De maio/95 a marco/2000, 96 pacientes com media de idades de 25,4±11,4 anos foram consecutivamente submetidos a substituicao da valva aortica por auto-enxerto pulmonar. O diagnostico pre-operatorio mais comum foi de insuficiencia aortica de origem reumatica e 89% encontravam-se em classe funcional II ou III. Todos realizaram ecocardiograma bidimensional com Doppler e 42 tambem foram submetidos a cateterismo cardiaco antes da operacao. O auto-enxerto foi implantado pela tecnica de substituicao total da raiz aortica em 85 casos, como cilindro intraluminal em seis e em posicao subcoronariana nos demais. A reconstrucao da via de saida do ventriculo direito foi feita com homoenxertos pulmonares (84) ou aorticos (12), conservados em solucao nutriente com antibioticos (34) ou criopreservados (62). Antes da alta hospitalar, todos repetiram o exame ecocardiografico e 30 foram submetidos a cateterismo cardiaco. Atraves deles, foi feita avaliacao do desempenho hemodinâmico dos auto e homoenxertos, assim como da funcao e massa ventricular esquerda. No periodo de acompanhamento, os pacientes foram examinados e repetiram o ecocardiograma a cada seis meses. Vinte pacientes, com tempo de evolucao superior a seis meses, submeteram-se a ecocardiografia de stress com dobutamina, para estudar o desempenho hemodinâmico dos auto e homoenxertos em condicao de exercicio. RESULTADOS: A mortalidade hospitalar foi de 6,2%. Apos um tempo medio de 32,1 meses (1 - 58), 98,9% dos pacientes estao vivos. A incidencia de pacientes livres de tromboembolismo, endocardite, disfuncao do auto-enxerto, disfuncao do homoenxerto, reoperacoes mitrais e de qualquer tipo de complicacao apos 41 meses e de 100%, 100%, 97,1%, 96,5%, 93,9% e 87,5%, respectivamente. O auto-enxerto pulmonar teve desempenho hemodinâmico fisiologico, com media de gradiente medio de 3,8±3,3 mmHg. O grau de insuficiencia valvar foi negligenciavel. Mesmo em condicao de exercicio, os gradientes nao se elevaram de forma significativa, com media de gradiente medio de 6,8±3,8 mmHg. A funcao hemodinâmica dos homoenxertos foi excelente na fase imediata, com gradiente medio de 4,1±4,6 mmHg. Houve, entretanto, discreto aumento desses gradientes na fase tardia, com media de 13,9±10 mmHg. Durante o exercicio, houve aumento significativo destes gradientes, que foram para 33,6±18,9 mmHg. Diâmetro do homoenxerto e idade do receptor tiveram correlacao inversa com o gradiente pulmonar tardio. O indice de massa ventricular diminui de 180±68 g/m2 no pre-operatorio para 117±32 g/m2 na fase tardia. A funcao ventricular no pos-operatorio tardio foi normal tanto em repouso como em exercicio na maioria dos pacientes. CONCLUSOES: O implante do auto-enxerto pulmonar em posicao aortica pode ser feito com baixa mortalidade imediata. A sobrevida tardia foi excelente, com baixa incidencia de complicacoes. O desempenho hemodinâmico dos auto-enxertos pulmonares foi proximo ao fisiologico tanto em repouso como em exercicio. Houve significativa regressao da massa ventricular esquerda, e, os indices de funcao ventricular tambem foram normais na fase tardia de pos-operatorio. Apesar dos homoenxertos da via de saida do ventriculo direito apresentarem desempenho hemodinâmico adequado na fase imediata, o aparecimento de discretos gradientes na fase tardia foi frequente.

Avaliação inicial de homoenxertos em posição pulmonar em crianças e adolescentes

Objective: Heart valve homografts - fresh or cryopreserved - are a good valvular substitute in infants and teenagers as they need no anticoagulation, have a higher resistance to infection and present a good hemodynamic performance. The objective of this report was to evaluate the initial postoperative results on pediatric subjects after homograft implant in pulmonary position. Methods: Fourteen homografts were implanted in pulmonary position from September, 1995 to December, 1997. Four of them were fresh (28.6%) and ten were cryopreserved (71.4%). Subjects ranged in age from 10 months to 17 years with 9 (64%) males and 5 (36%) females . The subjects were divided into two groups, as follows: A - aortic valve disease (Ross operation) and B - congenital heart disease. The diameter of the homografts ranged from 16 to 26 mm. The cardiopulmonary-bypass time ranged from 74 to 303 minutes and the aortic-occlusion time between 49 to 160 minutos. Results: A hospital death occurred. All the survivors were clinically, radiologically, electrocardiographycally and echocardiographycally monitored. There were 13 NYHA I patients and one NYHA II patients. The most common complications were low output syndrome, pericardial effusion and EKG abnormalities. All these ocurred in two patient but with a favorable outcome. Stenosis of the right ventricular outflow track was observed early on in two subjects with gradients of 44 and 23 mmHg. One of the pulmonary homografts was submitted to a successful balloon valvuloplasty due to a severe stenosis. The rheumatic patients are still receiving antibiotic therapy and without recurrence of the disease. Conclusion: Evaluation of the hemodynamics of the homografts, in pulmonary position, was satisfactory. One of the subjects has presented marked stenosis but, after a balloon valvuloplasty, his gradient decreased. Another patient has kept his preoperative NYHA classification. We believe was not correlated with the homograft (coagulation disorder). Its our belief that fresh and cryopreserved homografts are a satisfactory solution for the correction of congenital or acquired valve disease in infants and adolescents.

Operação de Ross: a intervenção ideal para pacientes aórticos jovens?

Background: Aortic valve prosthesis with adequate hemodynamic performance should allow more complete left ventricular mass regression and return left ventricular function back to normal. This possibly affects long term prognosis after aortic valve replacement. Objective: Assessment of hemodynamic performance of the pulmonary autograft in the aortic position and the regression of left ventricular mass after the Ross procedure. Material and Methods: Between May/95 and Mar/96, 45 patients with mean age of 27.1 years were submitted to a Ross procedure. Doppler echocardiography and cardiac catheterization were performed on all patients before hospital discharge to analyze the hemodynamic performance of the auto and homografts employed, as well as to evaluate left ventricular mass and function. Fourteen patients with follow-up longer than six months were sumitted to dobutamine stress echocardiography to study hemodynamic performance of the auto and homografts at during exercise. Results: Hospital mortality was 6%. After a mean follow-up of 12.8 months (1-23), there was one late sudden death. No valve related event was noted during this period. Immediate and late hemodynamic performance of the pulmonary autografts were normal with average mean gradients of 1.8 ± 0.6 mmHg and average maximum instantaneous gradients of 2.9 ± 0.9 mmHg. Valvular insufficiency was almost null. Even during exercise, gradients did not increase significantly with average mean gradients of 4.3 ± 2.5 mmHg and average maximum gradients of 10.4 ± 6.1 mmHg. Homografts used for right ventricular reconstruction exhibited excellent immediate hemodynamic performance. However, at late follow-up an increase in flow velocities was noted with an average of mean gradients of 10 ± 7.1 mmHg at rest and 26 ± 13.3 mmHg at exercise. Left ventricular mass index dropped from 168 ± 46 g/m2 preoperatively to 115 ± 32 g/m2 six months after the operation. Left ventricular function was normal at rest and during exercise in the marjority of patients. Conclusions: Given the normal hemodynamic performance of the autografts, the important decrease in left ventricular mass and the normal left ventricular function late postoperatively, the Ross procedure is considered the operation of choice for young patients who need aortic valve replacement.

Homoenxerto mitral: uma realidade

Background: the use of cryopreserved aortic valve homografts is associated with excellent quality of life, low morbidity and satisfactory durability. We expect to achieve similar results in the mitral position with the use of cryopreserved mitral homografts. Objectives: Evaluate the immediate and short-term results of mitral valve replacement with cryopreserved mitral homografts. Material and Methods: Between July/97 and February/98, 8 patients with a mean age of 40.3 ± 6.2 years were submitted to mitral valve replacement with cryopreserved mitral homografts. Operative technique consisted of latero-lateral papillary muscle fixation, a running continuous suture at annulus level and annuloplasty with a Carpentier ring. Before hospital discharge, all patients were submitted to Doppler echocardiographic control for assessment of valvar and ventricular function. Patients were requested to return at the first and subsequently every 3 months postoperatively for further clinical and echocardiographic control. Results: There was one early non valve-related death. Echocardiographic evaluation before hospital discharge revealed a mean mitral valve area of 3.1 ± 0.6 cm2 and a mean gradient of 3.5 ± 1.6 mmHg. Valvar insufficiency was graded as non-existent or trivial in four cases and mild in the remaining three patients. Ejection fraction which was 57 ± 7% pre-operatively was well preserved in the postoperative period (62 ± 6%). Pulmonary hipertension reduced significantly from 87 ± 15 mmHg pre-operatively to 48 ± 12 mmHg post-operatively. There was also a reduction in the left atrial cavity from 61 ± 10 mm to 53 ± 7 mm. No patient was lost to follow-up. After a mean follow-up time 4.1 ± 2.5 months, all patients are functionally well without postoperative events. Late echocardiographic control showed persistence of the good immediate results. Conclusions: The immediate and short-term results of mitral valve replacement with mitral homografts are satisfactory, demonstrating the feasibility of the technique. Longer follow-up periods are necessary to determine durability of this graft and to eventually expand its indications.

Experiência cirúrgica inicial com a operação de Ross (auto-enxerto pulmonar)

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.

Seguimento de 8 anos de prótese aórtica Medtronic-Hall: influência da anticoagulação oral na ocorrência de embolias

One hundred and sixty five survivors of isolated Medtronic-Hall aortic prosthesis operated on from September 1979 to September 1987 were studied. Ages varied from 14 to 68 years (m = 35.2) and 129 patients were male, 36 female. Preoperative diagnosis were 70 aortic insuficiency, 37 aortic stenosis and 39 double lesions. There were additionally 8 prosthetic dysfunctions, 8 acute infective endocarditis and 3 interventricular septal defects plus aortic insufficiency. One hundred and sixty three patients were followed (98.72), 9 of them being lost during the observation period. There were 45 late deaths, 59% SE 10.9% being the actuarial survival probality in 8 years. Twenty one patients suffered 26 embolic episodes, 69.8 SE 11.7% the probability of freedom from embolism and 39.7% SE 10.4% the chance of survival free from embolism. The rate of embolism episodes was 3,5% per patients/year in the entire series, 6 of them being lethal. In relation to the use of oral anticoagulation patients were divided into three sub-groups. Sub-group A included 144 patients, with a linearized incidence of 3.2% episodes per patients/year. Sub-group B included 21 patients who used anticoagulants after surgery, with an incidence of 1.9% per patients/year. Sub-group C comprised 9 patients who were put on anticoagulants after the occurence of an embolic episode. This sub-group presented 8.1 episodes per patients/year. It is concluded that it was not possible to doccument the influence of anticoagulation in the conditions prevailing during the observation of this series. After the occurence of one embolic episode the institution of oral anticoagulation was not effective in decreasing chance of its reccurence.

Parada circulatória total em cirurgia cardíaca pediátrica: relato de 130 casos

Deep hypothermic circulatory arrest (DHCA) increased the number of pediatric patients operated on our Service and it is an important aid for the correction of complex cardiovascular procedures. We studied 130 patients from January, 1995 to June, 1996. Patient ages ranged from 2 days to 16 years. The most frequent pathology was VSD (26%), tetralogy of Fallot (13%), TGA (10%) and AVSD (10%). All patients used membrane oxygenators, rectal temperature was maintained at a mean of 15,4°C. Mean perfusion time was 45 minutes. In the early postoperatory stage, low output was the most frequent complication (49 - 38%). Neurological changes occured in 27 patients (20%): 13 seizures (10%), 8 neuropsychologic disfunction (6.1%), 5 extrapyramidal signs (3,8%), 4 neuro-ophthalmic deficits (3%), 4 comas. 5 of these symptoms appeared early in the postoperative period and could be attributed to DHCA (3.8%). There were 20 (15%) deaths. 3 had a permanent neurologic deficit on discharge (2 dysartrias and 1 muscular hypertonya). We concluded that DHCA is useful for the correction of complex cardiac anomalies with a low risk of neurologic complications permanent. Our late follow up is too short for precise analysis of psycomotor development in these patients.

Monitorização de transplante cardíaco usando análises do eletrograma intracavitário

Serial intramyocardial electrogram recordings have been performed for noninvasive rejection monitoring in patients after heart transplantation using implanted telemetric dual-chamber pacemaker and fractally coated endocardial loads. The signals have been evaluated using the CHARM (Computerized Heart Acute Rejection Monitoring) system. The reports containing the trend curves of the rejection sensitive parameters show good correlation with the patients clinical course and the results of endomyocardial biopsy. Long-term cardiac transplant monitoring using intramyocardial electrograms is a valuable tool for clinical patient management.