Tracheal cryopreservation: caspase-3 immunoreactivity in tracheal epithelium and in mixed glands

Cryopreservation has an immunomodulating effect on tracheal tissue as a result of class II antigen depletion due to epithelium exfoliation. However, not all epithelium is detached. We evaluated the role of apoptosis in the remaining epithelium of 30 cryopreserved tracheal grafts. Caspase-3 immunoreactivity of tracheal epithelium was studied in canine tracheal segments cryopreserved with F12K medium, with or without subsequent storage in liquid nitrogen at -196°C for 15 days. Loss of structural integrity of tracheal mixed glands was observed in all cryopreserved tracheal segments. Caspase-3 immunoreactivity in tracheal mucosa and in mixed glands was significantly decreased, in contrast to the control group and to cryopreserved tracheal segments in which it remained high, due to the effect of storage in liquid nitrogen (P < 0.05, ANOVA and Tukey test). We conclude that apoptosis can be triggered in epithelial cells during tracheal graft harvesting even prior to cryopreservation, and although the epithelial caspase-3 immunoreactivity is reduced in tracheal cryopreservation, this could be explained by increased cell death. Apoptosis cannot be stopped during tracheal cryopreservation.

Tracheal cryopreservation: caspase-3 immunoreactivity in tracheal epithelium and in mixed glands.

Cryopreservation has an immunomodulating effect on tracheal tissue as a result of class II antigen depletion due to epithelium exfoliation. However, not all epithelium is detached. We evaluated the role of apoptosis in the remaining epithelium of 30 cryopreserved tracheal grafts. Caspase-3 immunoreactivity of tracheal epithelium was studied in canine tracheal segments cryopreserved with F12K medium, with or without subsequent storage in liquid nitrogen at -196 degrees C for 15 days. Loss of structural integrity of tracheal mixed glands was observed in all cryopreserved tracheal segments. Caspase-3 immunoreactivity in tracheal mucosa and in mixed glands was significantly decreased, in contrast to the control group and to cryopreserved tracheal segments in which it remained high, due to the effect of storage in liquid nitrogen (P < 0.05, ANOVA and Tukey test). We conclude that apoptosis can be triggered in epithelial cells during tracheal graft harvesting even prior to cryopreservation, and although the epithelial caspase-3 immunoreactivity is reduced in tracheal cryopreservation, this could be explained by increased cell death. Apoptosis cannot be stopped during tracheal cryopreservation.

[Bidirectional cavopulmonary diversion for tricuspid atresia. Experience in the National Institute of Cardiology]. / Derivación cavopulmonar bidireccional para la atresia tricuspídea. Experiencia en el Instituto Nacional de Cardiología.

Bidirectional cavopulmonary shunt is an alternative palliative procedure for patients with congenital cyanotic heart disease, specially those patients less than "ideal" candidates for a Fontan's procedure. We present our results with this shunt in patients with tricuspid atresia. Twenty patients with tricuspid atresia were operated on with this shunt, with these associated defects: 20 atrial septal defect, 17 ventricular septal defect, 10 pulmonary stenosis, 1 pulmonary atresia and 1 transposition of the great arteries. Sex: 10 males and 10 females; the age was 27 days to 6 years (mean 1.8 years), the weight was 3.2 kg to 24 kg (mean 10.7 kg), the mean pulmonary artery pressure was 11 to 24 mmHg (mean 17 mmHg), pulmonary vascular resistance was 1.5 to 5 UW (mean 3.1 UW). Postoperative oxygen saturation improved 15 to 120%. All patients survived the surgical procedure. Three patients died in the immediate postoperative period, 2 due to a complications in the postoperative period and 1 due to sepsis. There were two late deaths, 1 sudden death after 6 months of the shunt, and 1 due to sepsis after a Fontan's procedure. Four patients presented pleural effusion and 2 pericardial effusion, they resolved well. We have 15 patients alive and well, in functional class I, and minimal cyanosis. We can conclude that this surgical procedure is useful in the management of patients with tricuspid atresia.

[Reconstruction of the normal right ventricle outflow tract in the Ross operation]. / Reconstrucción del tracto de salida normal del ventrículo derecho en la operación de Ross.

Now a day there are many surgical procedures that require intervention on the normal right ventricular outflow tract (RVOT) and its reconstruction. We present the surgical anatomy of the pulmonary root in the normal RVOT and its reconstruction in the Ross operation in 13 patients operated on from February 1992 through February 1994. The surgical excision of the pulmonary valve was done and in order to keep right ventricle-pulmonary artery continuity (RV-PA), autologous pericardium tubes with bovine pericardium valve [done at the Instituto Nacional de Cardiología (INC)], were elaborated during the surgical procedure in all patients. The postoperative period and its clinical status was satisfactory in all cases, without transpulmonary gradient or regurgitation. We conclude that is important to know the surgical anatomy of the pulmonary root in order to avoid irreversible damage. In the other hand, it is worthy to know the different choices to reconstruct RVOT and its postoperative clinical course.

[Mitral valve replacement by mechanical disk valve. A surgical alternative]. / Substitución valvular mitral con prótesis mecánica de disco. Una alternativa quirúrgica.

From July to December 1993, 10 patients underwent mitral valve replacement with mechanical disc valve and running suture, preserving the posterior mitral valve apparatus. There were 6 men and 4 women, with a mean age of 44.2 years (25 to 63 years old). Three patients were in functional class II of the NYHA, 5 in functional class III and 2 in functional class IV. Eight patients were operated on for simple mitral valve replacement, of which, 2 underwent the first replacement 4 the second replacement and 2 the third replacement. One patient underwent double valve replacement (mitral and aortic valves) plus "bicuspidization" of the tricuspid valve and one patient underwent myocardial revascularization with two grafts of reverse saphenous vein besides mitral valve replacement. We used cardiopulmonary bypass in all patients with moderate hypothermia at 28 degrees and cardiac protection with cold cardioplegia at 4 degrees with potassium. One to 2 dosis of cardioplegia were required. Aortic cross clamping time was 37 minutes and 64 minutes of cardiopulmonary bypass in the patients operated on of simple mitral valve replacement. Supported by these preliminary results, we conclude that this surgical alternative is effective and safe with less ischemic and cardiopulmonary bypass time, preserve the posterior mitral apparatus and avoid disc jamming by the residual leaflet or tendinous chordae.

[Intraoperative circulatory collapse due to a coronary spasm following successful coronary revascularization]. / Colapso circulatorio intraoperatorio debido a espasmo coronario después de revascularización coronaria exitosa.

Coronary artery spasm is recognized cause of angina and circulatory collapse during the operative and early postoperative period following cardiopulmonary bypass for coronary artery surgery. We present our experience with hemodynamical collapse during cardiopulmonary bypass weaning, which were refractory to treatment with inotropics such as noradrenaline and adrenalin and vasodilators such as nitroglycerin. The electrocardiographic changes, poor answer to medical treatment following successful cardiopulmonary bypass for coronary artery surgery, good myocardial protection and complete revascularization suggested severe coronary artery spasm. We used sublingual nifedipine, achieving hemodynamical stability and stopping inotropic support and cardiopulmonary bypass. We review the literature about pathophysiologic mechanism and treatment of coronary artery spasm.

[Pulmonary valve autograft for aortic valvulopathy]. / Autotrasplante de la válvula pulmonar para valvulopatía aórtica.

Twelve patients were operated on between February 1992 and June 1993 because aortic valve disease with pulmonary autograft replacement of the aortic valve and reconstruction of the right ventricular outflow tract with a valved tube of autogenous pericardium and bovine prosthetic pericardium valve made at the Instituto Nacional de Cardiología Ignacio Chávez. Aortic and pulmonary annular diameters were taken preoperative in all patients by transthoracic echocardiography. During the surgical procedure, transthoracic echocardiography was done in order to assess valvular function of the pulmonary autograft. There was no peri-operative morbi-mortality and no anticoagulation was required. Post operative evolution was satisfactory in all patients and were discharged after transthoracic echocardiography evaluation. Annular diameters correlated with the trans-surgical annular measurements. We conclude that the use of the pulmonary autograft in selected cases can be done, in order to relieve aortic valve disease, without significant morbi-mortality as compared with single aortic valve replacement.

[The use of the right gastroepiploic artery for posterior myocardial revascularization]. / Uso de la arteria gastroepiploica derecha para la revascularización del miocardio posterior.

From August 1992 to June 1993, eight patients underwent myocardial revascularization in whom the right gastroepiploic artery was used in order to reach the posterior myocardium. All patients were men. Ages ranged from 32 to 65 years, with a mean of 51 years. The left internal mammary artery was used in all patients. The right internal mammary artery was used in three patients and the right inferior epigastric artery was used as a free graft in one patient. There was three bypass grafts per patient with a total of 20 arterial grafts in which 19 were pediculated and one as a free graft. The aortic clamping time ranged from 52 to 80 minutes with a mean of 72 minutes. All patients received combined antegrade/retrograde cardioplegia delivery through the aortic root and the coronary sinus respectively for myocardial protection. There was no need to use inotropic support for ventricular assistance. The right gastroepiploic artery was used in order to reach the posterior myocardium and it was passed through the antero-hepatic trans-diaphragmatic route. There was no complications with the use of the right gastroepiploic artery in the early and late postoperative period. The course was excellent in all patients and they remain asymptomatic. We conclude that the use of the right gastroepiploic artery for coronary bypass grafting in order to revascularize the posterior myocardium is an excellent choice. There were no technical difficulties nor gastric complications and we are increasing our experience in order to establish its routine use.