Porcine stentless valve/bovine pericardial conduit for right ventricle to pulmonary artery.

BACKGROUND AND OBJECTIVES: We assessed the long-term outcome of a glutaraldehyde-preserved bovine pericardial conduit containing a stentless composite porcine aortic valve. METHODS: Between November 1985 and May 1995, 33 stentless porcine valves attached to bovine pericardial conduits were used in 33 patients with complex congenital cardiac malformations. These patients required a conduit between the right ventricle and the pulmonary artery because of an absent or inadequate pulmonic artery. All patients were approached by midsternotomy. One patient with pulmonic atresia and an interventricular septal defect required left thoracotomy for ligation of collaterals. RESULTS: Of the initial 33 patients, clinical follow-up was performed in 23 discharged patients (70%) for 1.7 to 10.5 years. The echo-Doppler analysis performed in each of the 23 followed patients showed excellent conduit and valve function in all but 4 patients, in whom a valve gradient of 60 mm Hg was noted. There was no tissue structural failure noticed in this study. CONCLUSIONS: The SJM Biocor (Belo Horizonte, Brazil) bovine pericardial stentless valved conduit performed well as a substitute for the right ventricle to pulmonary artery connection.

Surgical technique of implanting the stentless porcine mitral valve.

The new stentless porcine mitral valve was developed to serve as an anatomically correct substitute for a diseased mitral valve. Extensive acute animal experimentation was performed, and from this the logical sequence for selecting the correct valve size and the specific technique for implanting it were determined. The following are the major steps to successfully implant a mitral stentless valve: First, mitral valve complex analysis must be done to determine the correct procedure to be performed and the feasibility of using the stentless mitral valve. Second, the correct size of stentless mitral valve must be chosen. Third, the papillary muscle anatomy must be assessed to determine the site and number of sutures necessary for securely holding the new origin of the new chordae. Fourth, the papillary muscle sutures must be anchored to the free pericardial edge of the new chordal origin. Fifth, the chordal alignment with both trigonal areas must be perfect. Sixth, the annulus may be sutured using either continuous or interrupted sutures. Perioperative echocardiography, preferably transesophageal echocardiography, should be done in every patient. Although reoperation was necessary in 5 patients (non-valve-related), the results in 74 patients (3 early and 3 late non-valve-related deaths excluded) followed up for at most 26 months (mean, 14 months) have been excellent. The quality of the results obtained in this initial clinical trial has reinforced our current preference for this valve in patients requiring mitral valve replacement. Longer follow-up is required to confirm that these good results continue.

[Atriofascicular connection with slow conduction and longitudinal dissociation. Electrophysiologic evidence and clinical implications]. / Conexão átrio-fascicular com condução lenta e dissociação longitudinal. Comprovação eletrofisiológica e implicações clínicas.

We report on a patient with paroxysmal left bundle branch block-like tachycardia with electrophysiologic findings suggestive of nodoventricular pathway (ventricular pre-excitation dependent on slowing of AV conduction, and accessory pathway with exclusive anterograde conduction). There was no pre-excitation during sinus rhythm but it was brought on by intravenous verapamil. Atrioventricular node conduction curves showed no signs of duality. Diagnosis of an atriofascicular pathway with decremental properties was based on the following findings: 1) absence of AV dissociation during reciprocating tachycardia; 2) absence of fusion beats or narrowing QRS complexes during tachycardia; 3) advancement of right ventricular activation with late atrial extrastimuli delivered during antidromic tachycardia at a time of low right atrium refractoriness; 4) observation that earliest ventricular endocardial electrogram during tachycardia (activation mapping) was simultaneous with the right bundle potential; 5) surgical ablation of the accessory pathway by endocardial incision at the right anterior aspect of the tricuspid ring, far away from the AV node region. Evidences showing anterograde longitudinal dissociation of the accessory pathway included cycle length alternation during tachycardia and duality of accessory pathway conduction times and refractory periods. We hypothesize that reentry occurring in such AV node-like structure could give to a pre-excited tachycardia with AV dissociation mimicking antidromic tachycardia associated with nodoventricular pathway.

[Surgery for Wolff-Parkinson-White syndrome in the first year of life]. / Cirurgia para síndrome de Wolff-Parkinson-White no 1. ano de vida.

A case of surgical treatment for reentrant atrioventricular tachycardia in a 7 months old child is reported. Episodes of tachycardia were repetitive and long-lasting, often leading to signs of hemodynamic impairement, and were not controlled by antiarrhythmic drugs. The electrophysiologic study showed a circus-movement tachycardia utilizing a concealed accessory pathway located at the anterior septal aspect of tricuspid anulus. The child underwent successful surgical treatment by the endocardial technique. Few minutes after weaning from extracorporeal circulation, developed T wave inversion followed by acute right ventricular dysfunction and ventricular fibrillation. Others ischemic like episodes, maybe as a result of coronary artery spasm, occurring in the next 6 hours were successfully treated with isosorbide dinitrate. At 18 months follow-up, the child is free of tachycardia and has normal atrioventricular conduction.

Stentless porcine and pericardial valve in aortic position.

Fifty-seven patients underwent aortic valve replacement with a stentless glutaraldehyde-fixed bioprosthesis; 27 received a porcine aortic valve and 30 had a bovine pericardial valve. Two groups of 30 patients each who had aortic valve replacement with a tilting-disc mechanical valve or a stented porcine bioprosthesis served as controls. There were no differences in sex, body surface area, valve lesion, and valve size among the four groups. Results were assessed on a Doppler-based determination of maximum velocity across the valve, aortic valve area, and degree of valve regurgitation. Velocity across the valve was significantly less with stentless pericardial valves than with stentless porcine valves, stented bioprostheses, and mechanical valves. Stentless valves had a significantly larger aortic valve area when compared with stented valves. Mild central aortic insufficiency was detected more often with stentless pericardial than with stentless porcine bioprostheses (p = 0.04). Stentless valves showed a higher incidence of complete atrioventricular block when compared with stented valves (p = 0.04). Long-term studies are now warranted to assess the durability of both types of stentless valves.

[Transcoronary chemical ablation of ventricular tachycardia in a patient with chronic chagas cardiomyopathy]. / Ablação química transcoronária de taquicardia ventricular em portador de cardiopatia chagásica crônica.

A case of recurrent ventricular tachycardia in the setting of chronic chagasic heart disease refractory to conventional antiarrhythmic agents as well as high doses of amiodarone (600 mg/day) is reported. Left ventriculography disclosed an apical aneurysm and a filling defect image suggestive of a thrombus. Sustained monomorphic ventricular tachycardia with the same QRS configuration as "clinical" tachycardia could be induced by means of right ventricular programmed electrical stimulation. The risk of systemic embolization precluded endocardial activation mapping of ventricular tachycardia. Intracoronary cold saline injections were done during induced ventricular tachycardia looking for a coronary artery branch related to the arrhythmogenic substrate. Cold saline mapping results pointed to an apical site of origin. Next step was intracoronary injection of ethyl alcohol in the distal part of the left anterior descending artery leading to a small and uncomplicated myocardial infarction. Control programmed stimulation was unable to reinduce ventricular tachycardia. Clinical outcome was uneventful and there was no recurrence of clinical arrhythmia in 6 months of follow-up.

[Cardiomyopathy induced by incessant ventricular tachycardia ("tachycardiomyopathy"): cure after control of arrhythmia]. / Miocardiopatia induzida por taquicardia ventricular incessante ("taquicardiomiopatia"). Cura após controle da arritmia.

A case of severe dilated cardiomyopathy in a young boy presenting with incessant ventricular tachycardia, who had been referred for heart transplantation is reported. Complete resolution of dilated cardiomyopathy followed arrhythmia control with oral amiodarone. Such evolution strongly suggests a cause-effect relationship between incessant ventricular tachycardia and dilated cardiomyopathy in this particular case.

Clinical results with the Biocor porcine bioprosthesis.

In order to evaluate our clinical results with the use of the Biocor prosthesis, a total of 1,101 patients were studied. Follow-up was from 1 to 96 months (mean 48); cumulative follow-up in the aortic group (385 patients) was 1,230 patient years and in the mitral group (716 patients) 3,018 patient years. Mitral patients had 102 late complications (14.24%), and aortic patients had 51 (13.2%). A total of 220 patients were under 20 years of age (176 mitral, 44 aortic). Intrinsic valve failure in this subgroup was found in 43% of mitral patients and 29% of aortic patients. Prosthetic endocarditis was more frequent in the aortic group (45%) than in the mitral group (29.9%). Sixty-two patients were reoperated, with a hospital mortality of 12.6%. Reoperation was more frequent in the mitral group and in patients under 20 years of age. The actuarial curve free mortality related to the bioprosthesis was 97.1% (32 patients). At the 8-year follow-up, 96.9% of the aortic versus 95.2% of the mitral group were free of valve dysfunction, and the majority were in Classes I or II of the New York Heart Association (NYHA) classification. The incidence of reoperation, although significant, is acceptable, especially since the bioprosthesis offers a safer alternative than mechanical prostheses followed for similar periods. Analysis of our results suggests the need for continued research for an ideal bioprosthesis.

[Ventricular fibrillation in a patient with ventricular dysplasia and mitral valve prolapse]. / Fibrilação ventricular em portador de displasia ventricular e prolapso valvar mitral.

A 30 year-old male patient with arrhythmogenic right ventricular dysplasia was submitted to implantation an automatic cardioverter-defibrillator. So far he is well in a follow-up of 7 months.

The use of PTFE graft to correct anomalous drainage of persistent left superior vena cava.

A new technique to correct persistent left superior vena cava (LSVC) drainage into the left atrium is described in a 14-year-old patient with situs inversus, left atrial isomerism common atrium, and mitral valve regurgitation. During surgery, occlusion of the LSVC markedly increased the venous pressure, precluding its ligation. Because of the malposition of the heart and the unusual atrial anatomy, correction with an intra-atrial baffle was not attempted. After correcting the intra-cardiac anomaly, the LSVC was divided and anastomosed to the "right" atrial appendage using a segment of PTFE graft. The postoperative course was uneventful and an angiogram demonstrated excellent performance of the graft.

New graft for the surgical treatment of small vessel diseases.

The purpose of this study is to analyze the use of a new Bovine Internal Mammary Artery (BIMA) graft in the surgical treatment of small arteries. Results were based on a study of 20 patients undergoing coronary revascularization, 9 patients undergoing modified Blalock-Taussig procedure, 15 patients requiring access for hemodyalisis, 6 patients undergoing peripheral revascularization, and 15 patients undergoing revascularization for impotence. Patients are well, and post-operative angiogram, when possible, showed patent BIMA grafts. Speadier anastomosis was possible, decreasing actual surgical time. Although long-term patency studies are required, the results of the present study justify the use of the BIMA graft as a small artery substitute if a healthy saphenous vein or internal mammary graft are not available. The ready availability in all sizes, superior handling, less likelihood to kinking, proper matching with the native artery, elasticity properties, and low cost, make this graft necessary in the armamentarium of the cardiovascular surgeon.

Avaliação hemodinâmica da prótese heteróloga Biocor / Hemodynamic evaluation of Biocor heterologous prosthesis

Sao apresentados os resultados do estudo hemodinamico em 16 pacientes portadores de 18 proteses Biocor (porcina, com orificio modificado, preservadas em glutaraldeido).Em 4 casos, o debito cardiaco e os gradientes foram medidos antes e apos exercicio. Em 8 pacientes com protese mitrais, a pressao venocapilar media caiu de 28,9 +/- 6,1 mmHg para 13,3 +/- 4,2 mmHg pos - operatorio e as proteses apresentaram um gradiente final diastolico medio de 0,8 mmgH. Seis pacientes tinham proteses aorticas, com gradiente medio de 6 mmgH. Dois pacientes com dupla protese, apresentaram bons resultados em relacao a valvula mitral e gradientes de 29 e 48 mmHg nas valvulas aorticas (ambas numero 23). Conclui-se que as valvulas Biocor apresentaram bom desempenho hemodinamico, com ausencia de gradientes na maioria dos pacientes estudados, boa abertura dos folhetos, sem refluxos significativos

Resultados clinicos e hemodinamicos da bioprotese Biocor. Estudo cooperativo preliminar. / Clinical and hemodynamic results of the Biocor bioprosthesis. Preliminary cooperative study

Este estudo representa a avaliação dos resultados clinico e hemodinâmico das bipróteses Biocor, entre 1/07/81 e 30/09/82.Embora tenham sido realizados 700 implantes no Brasil, este estudo relata a avaliação de um grupo inicial de 330 pacientes, durante o período de 15 meses. A mortalidade hospitalar foi 9,71% e a mortalidade tardia, 0,66%, ambas sem ligação direta com a válvula propriamente dita. As características hemodinâmicas foram inteiramente satisfatórias, como foi observado em estudos hemodinâmicos pós-operatórios resultado clinico mostrou uma nítida melhora na classificação funcional de acordo com a New York Heart Association (NYHA)