Long-term storage in liquid nitrogen does not affect cell viability in cardiac valve allografts.

Liquid nitrogen is the most common medium used by tissue banks for the storage of cryopreserved heart valves. This study evaluates the effect of the length of storage on human cryopreserved heart valves. Human tissues (14 aortic and 13 pulmonary) were frozen in a controlled-rate freezer (1 degrees C/min) and stored in the liquid phase of a nitrogen tank for 9.1+/-1.6 years. The preservative solution was medium M199 containing 5% human serum albumin and 10% Me(2)SO. After thawing in a water bath at 42 degrees C, the cryoprotectant was removed. Then, fragments from vascular wall and leaflet were dissected. Explant cultures and histological studies were performed in order to assess cell viability and structural integrity. CD90 and CD31 expression was analysed in cultured cells using flow cytometry. Light microscopy, immunofluorescence staining and laser scanning confocal microscopy were used to evaluate cell viability and extracellular matrix components. Electron microscopy was used for ultrastructural study. Cell cultures could be obtained from all the specimens assayed. Cells grew from explants showing a fibroblastic phenotype. CD90 expression was common in cultured cells but a low percentage of cells expressed CD31. Histological results showed a good preservation estructure in both leaflets and vascular walls. Morphological features of cellular irreversible damage were very rare. No differences which could be due to length of allograft storage period were observed. We concluded that allografts stored in liquid nitrogen up to 13 years did not significantly undergo loss of cell viability other than that due to disinfection, freezing and thawing protocols.

Phylogenetic relationships of dengue-1 viruses from Argentina and Paraguay.

We sequenced the Capsid-pre Membrane (C/prM) and the Envelope-Nonstructural protein 1 (E/NS1) regions of 24 recent isolates of dengue-1 (DEN-1) from South America. This included 12 Argentinean and 11 Paraguayan DEN-1 strains isolated in 2000 plus a Paraguayan strain isolated in 1988. These sequences were compared with published sequences of DEN-1 isolated worldwide to determine the origin of these isolates. Pairwise comparisons of strains from Paraguay and Argentina revealed a nucleotide divergence of 0-5% in the E/NS1 region and 0-3% in the C/prM region. Our results showed that these viruses belong to the same genotype, but can be separated into two clades. Interestingly, both clades circulated simultaneously in the same geographic area during the 2000 outbreaks. Amino acid differences were found between both clades in the C/prM region at position 100 (Lys vs. Arg) and in the E/NS1 region at positions 722 (Ala vs. Thr). Although the geographic movement of DEN-1 virus can not be unequivocally traced from the genetic relationship determined here, our results suggest that the recent epidemics in Argentina and Paraguay were due to the re-emergence of a previously circulating strain, or to the virus circulating unnoticed, rather than to the introduction of a new genotype.

Long-term clinical experience with the Omnicarbon prosthetic valve.

BACKGROUND: From February 1985 to December 1994, 781 Omnicarbon valve prostheses were implanted in 647 patients. These were 357 male and 290 female patients with a mean age of 53.5+/-10.5 years (range, 4 to 78 years). Before operation, 81% of the patients were in New York Heart Association class III or IV, 16% were in class II, and only 3% were in class I. METHODS: There were 227 aortic valve replacements (AVR) (35%), 286 mitral valve replacements (MVR) (44%), and 134 double-valve replacements (DVR) (21%) (AVR + MVR). Follow-up was 96.3% complete and consisted of 2,746 patient-years (mean follow-up, 4.6 years, and maximum follow-up, 10.7 years). RESULTS: Hospital mortality rates were 7.0% for AVR, 8.0% for MVR, and 8.2% for DVR. The annualized rate of anticoagulant-related hemorrhage was 0.8% per patient-year, and thromboembolism occurred at a rate of 0.7% per patient-year. No structural failure was observed during 10-year follow-up. Twenty-one instances of nonstructural dysfunction (two, pannus growth, and 19, dehiscence) of the Omnicarbon valve occurred in 20 patients, an incidence of 0.8% per patient-year. Hemolytic anemia was observed only in the presence of valvular dehiscence (6 of 19). Eight patients (0.3% per patient-year) had development of prosthetic valve endocarditis (4, AVR; 2, MVR; and 2 DVR). At the end of 10 years of follow-up, 91% of the survivors were in New York Heart Association class I or II. The overall survival rate at 10 years was 82.5%+/-2.6% (85.0%+/-3.9%, AVR; 81.0%+/-4.1%, MVR; and 82.5%+/-2.6%, DVR). Considering only valve-related deaths, the survival rate at 10 years was 91.9%+/-2.4% (90.0%+/-2.7%, AVR; 93.1%+/-3.8%, MVR; and 90.0%+/-1.8%, DVR). CONCLUSIONS: Clinical results over a 10-year follow-up are excellent with the Omnicarbon prosthesis.

[Cardiac transplant in single ventricle]. / Transplante cardíaco en el ventrículo único.

Univentricular heart is an uncommon congenital heart disease. A select group of these patients (those with severe pulmonary stenosis or atresia) can reach adult age with different degrees of heart failure and severe chronic hypoxemia. Patients with adequate pulmonary tree development are likely to undergo heart transplantation when usual palliative techniques are contraindicated. Three cases of univentricular heart with pulmonary stenosis in which heart transplantation was the optimal choice are reported. Different techniques used to assess pulmonary tree development are analysed.

[Predictive variables of early mortality after orthotopic heart transplant in adults]. / Variables predictoras de mortalidad precoz tras el trasplante cardíaco ortotópico en adultos.

OBJECTIVE: The purpose of the study was to analyze some variables of donors, recipients and surgical procedures in order to discover factors that could predict mortality during the early stage (< 30 days) of orthotopic heart transplants. MATERIAL AND METHOD: 125 consecutive orthotopic heart transplants in adults were analyzed. The average age was 51 +/- 11 (range: 12-67), 109 (87%) were men, 16 were women (13%). Two groups were compared: 15 patients who died within 30 days after heart transplant and 110 who survived during that period. Immunosuppressive protocol: preoperative: Cyclosporin + Azathioprine. Intraoperative: Methylprednisolone Postoperative: Methylprednisolone (first 24 h), antilymphocyte monoclonal antibodies (7-10 days after heart transplant) + Cyclosporin + Azathioprine + Corticoids. The following parameters of the recipient were analyzed: sex, age, weight, size, thoracic perimeter, pretransplant cardiopathy, previous thoracic operations, functional stage or need for catecholamines during the days prior to the transplant, pulmonary artery pressure and resistance, history of systemic arterial hypertension, elevation of creatinine, blood type, urgent transplant indication, receptor/donor weight relationship. The following parameters of donors and operation were analyzed: sex, age, weight, thoracic perimeter, period in intensive care unit, dose of dopamine and dobutamine, blood type, origin of the organ, cause of death, ischaemia time, cardiopulmonary by-pass time and cardioplegia type. RESULTS: The rate of early mortality was 12%. The univariate analysis showed differences in: prior cardiovascular surgery, receptor blood type, need for urgent transplantation, pulmonary artery resistance > 2.5 Wood Units, cardiopulmonary by-pass time, weight relationship between receptor and donor. The death cause of the donor proved significant. On multivariate analysis, the following parameters independently predicted early mortality: history of operation with extracorporeal circulation, high pulmonary artery resistance, urgent transplant, receptor/donor weight relation and time of extracorporeal circulation. CONCLUSIONS: We believe that the results of our experience can help to stratify the risk in the orthotopic heart transplant recipient and even to contraindicate the procedure in some cases showing an accumulation of poor prognostic factors in borderline recipients.

[Heart angiosarcoma and heart transplantation. Report of a case]. / Angiosarcoma cardíaco y trasplante cardíaco. A propósito de un caso.

We present the case of a 29-year-old women with a cardiac primary angiosarcoma diagnosis. The initial symptom was a cardiac tamponade. The tests for screening metastasis proved negative. She was preoperatively treated with chemotherapy, followed by a heart transplant. There were no incidents related to surgery nor to the transplant except for a rejection in the second week biopsy. Four weeks after the transplant, the patient had a sudden dyspnea, the radiological tests confirmed the existence of a massive pleural overflow and lung and pleural metastasis. All types of therapeutical approaches were rejected except for pleurodesis. The patient died 60 days after the heart transplant.

[The use of cryopreserved homografts in reconstructing the right ventricular outflow tract in congenital cardiopathies]. / La utilización de homoinjertos crioconservados en la reconstrucción del tracto de salida del ventrículo derecho en cardiopatías congénitas.

In recent years the use of cryopreserved allograft valves has become very popular. Homograft valves have been used for aortic valve replacement and for reconstruction of the outflow tract of the right ventricle for more than 30 years with very good results. Recently the method of cryopreservation has made possible the creation of valve banks. The use of this cryopreserved valves has obtained very good short and medium term results. We present our experience with the use of cryopreserved allograft valves in the reconstruction of the right ventricular outflow tract in the treatment of complex cardiac malformations. We have operated 15 children. Six were diagnosed of different types of transpositions of the great arteries with ventricular septal defect and pulmonary atresia or stenosis. There were 2 deaths not related to the use of the allograft valves. Nine other patients were diagnosed of different types of complex cardiac malformations. One patient with a univentricular heart and pulmonary stenosis and a neonate presenting with a truncus arteriosus communis died after the operation; again the deaths were not related to the use of the homograft conduits. Our technique of cryopreservation consists in the procurement of aortic and pulmonary valves from multiorgan donor patients. The valves are sterilized in antibiotics for 48 hours. Then the process of freezing is began with a period of progressive cooling down to -40 degrees C and second phase of storage in liquid nitrogen to a temperature of -178 degrees C. The short and medium term results are very satisfactory. We have not seen late important complications.

Blunt chest injuries in 1696 patients.

We review 1696 patients with blunt chest trauma. Road traffic accidents were the main cause of injury followed by domestic falls and labour accidents. Outdoor falls and sport accidents accounted for a small number of injuries. For clinical evaluation, Stoddart's score was used. The injuries were considered as minor in 710 patients, intermediate in 740 and severe in 246. Global in-hospital mortality was low (5%) but increased to 37% when only patients with multiple severe injuries were considered. Thoracic wall fractures were present in 1419 patients. Flail chest was diagnosed in 140 patients and pulmonary contusion in 275. Diaphragmatic rupture was present in 40 patients and tracheobronchial injury in 6. Cardiovascular injuries occurred in 55 patients. Associated extrathoracic injuries were seen in 611 patients: 923 patients were clinically observed and/or medically treated. An intercostal tube was inserted in 638 patients. Thoracotomy was undertaken in 105 patients. Surgical fixation for flail chest was carried out in 29 patients. The results were generally good: 9 patients did not need any mechanical ventilation and 11 were ventilated for a short period. No deaths were due to the surgical procedure. The authors maintain that a selective attitude restricting, but not ignoring, surgical stabilization is the best policy.

Bronchial fistula to the mediastinum in a heart-lung transplant patient.

We present a case of heart-lung transplantation complicated by bronchial perforation as the cause or consequence of prolonged lung infection. Periodic bronchoscopic and radiological follow-up showed resolution of the condition following adequate antibiotic and physiotherapeutic treatment.

Management of non-tumoral tracheal stenosis in 112 patients.

From January 1973 to August 1989, 112 patients with non-tumoral tracheal strictures were treated in our unit. In 102 patients, the stenosis followed respiratory support. Eighty-one patients were treated surgically; the rest required only endoscopic therapy. In 28 patients, surgical treatment followed failure of endoscopic management. Of the patients submitted to surgery an isolated tracheal stenosis was present in 54 cases while a laryngotracheal stricture was the lesion in the other 27. Tracheal resection and end-to-end anastomosis was performed in the former group. Rethi, Pearson and Couraud procedures, respectively, were carried out in the latter. We emphasize the difference in the results achieved in the first 5 years and those obtained in the last 10 years. In the former period, 7 reoperations were needed. On the other hand, although the overall mortality of both series was 9%, it decreased to 2% during the last 10 years. Excellent or good ultimate results were achieved in 92% of survivors. Finally, we stress the differences in the proportion of reinterventions and definitive failures in the surgical treatment of isolated tracheal stenosis compared to laryngotracheal strictures.

Late cardiac tamponade after open heart surgery.

Delayed cardiac tamponade after open heart surgery is relatively uncommon, but constitutes a life-threatening condition that must be diagnosed and managed promptly. We report 21 patients who developed cardiac tamponade 5 to 53 days after open heart operations. Possible etiological factors included anticoagulant therapy (19 patients), excessive mediastinal drainage in the postoperative period (10 patients), postpericardiotomy syndrome (4 patients), and coagulation disorders (1 patient). The clinical presentation was insidious and the diagnosis was often difficult to establish at the outset. A high index of clinical suspicion and echocardiography were the most reliable means to reach an early diagnosis. Twenty patients in whom delayed tamponade was suspected were operated and all of them survived. In one patient tamponade was not diagnosed antemortem and he died; on autopsy left heart compression by a large loculated clot was found. Decompression of the pericardial space can be accomplished by pericardiocentesis or by surgical means (subxiphoid pericardiotomy, median sternotomy, or thoracotomy). Although pericardiocentesis alone may be effective, mainly when the postpericardiotomy syndrome is the suspected etiology, we recommend open procedures since the presence of blood clots and adhesions has been a frequent finding.

Pregnancy after heart valve replacement.

Thirty-two women, aged 21 to 44 years, who had undergone single (25) or multiple (7) heart valve replacement conceived 46 times and gave rise to 33 live-born infants. There were 12 abortions and one stillborn; a premature baby died 24 hr post-partum. Twenty-eight patients had mechanical prostheses and 4 had porcine xenografts, 29 patients being anticoagulated with acenocoumarol during the pregnancy. Cardiac status remained clinically satisfactory under medical treatment in all but one patient who developed heart failure. Fetal complications included cerebral hemorrhage in 1 premature infant, low birth weight in 3 newborns and 1 case of nasal hypoplasia. The incidence of abortion has decreased significantly during the latter part of our experience. It was significantly greater in patients with mitral prostheses. This review suggests that inadequate cardiac function, excessive anticoagulation and a history of primary infertility may increase the risk of abortion. Better control of anticoagulant therapy (accepting an elevation of the therapeutic limit) and improved prevention of pregnancy in high-risk patients are considered responsible for the improved results seen in recent years.

Mitral valve replacement and splenectomy in a patient with chronic idiopathic thrombocytopenic purpura.

We report the management of a patient with chronic idiopathic thrombocytopenic purpura and mitral valve disease. Although a two-stage approach was planned (splenectomy followed by mitral valve replacement one month later), the patient developed medically-resistant heart failure, and splenectomy plus mitral valve replacement were performed during the same operation. The platelet count at operation was 20,000/mm3. Platelet transfusion, used at the end of cardiopulmonary bypass, was considered no longer necessary in the postoperative period, as the platelet count quickly increased after the first postoperative day. The postoperative course was uneventful. Though we believe the two-stage surgical approach is preferable, our case shows that open-heart operations and splenectomy can be successfully performed simultaneously in patients with idiopathic thrombocytopenic purpura.

L-malposed great arteries with situs solitus and concordant atrioventricular connection.

Reports on surgical repair of cases with L-malposition of the great arteries with situs solitus atrialis and concordant atrioventricular connection are uncommon. A review of the anatomical characteristics of these cases has shown several peculiarities that may have considerable important in planning operation. Among them we emphasize the morphology of the ventricular septal defects, possible outflow tract obstructions and coronary artery course, anomalies of the atrioventricular valves and the course of the conduction system. Each of these aspects is reviewed from a surgical viewpoint in the light of our combined previous surgical and anatomical experience and of a review of previous reports by other authors.