Biomedical subjects
Publications and source records attributed to J J Lamberti.
Mediastinitis following congenital heart surgery is relatively uncommon but is usually seen in the setting of postoperative low cardiac output. Conservative treatment utilizing debridement and irrigation is associated with significant morbidity and mortality. We report the successful application of the omental transfer technique in the treatment of mediastinitis in a 6 month old.
The Epstein-Barr Virus (EBV) causes infectious mononucleosis, and has been strongly associated with certain human cancers. The virus is thought to exclusively bind to B lymphocytes and epithelial cells via receptors (CR2/CD21) that also interact with fragments of the third component of complement (C3). Recent evidence, however, has challenged this belief. We have used two-color immunofluorescence analysis using biotin-conjugated EBV and streptavidin-phycoerythrin along with fluorescein-conjugated anti-T cell antibodies and demonstrated that CD1-positive, CD3-dull (immature) human thymocytes express functional EBV receptors. In four replicate experiments, the binding of EBV to thymocytes ranged between 8 and 18%. This interaction is specific as evidenced by inhibition with nonconjugated virus, anti-CR2 antibodies, aggregated C3, and an antibody to the gp350 viral glycoprotein that the virus uses to bind to CR2. EBV can infect the thymocytes as evaluated by the presence of episomal EBV-DNA in thymocytes that had been incubated with the virus as short as 12 days or as long as 6 weeks. Episomal DNA analysis was performed by Southern blotting with a EBV-DNA probe that hybridizes to the first internal reiteration of the viral DNA. The presence of the EBV genome is also supported by the detection of EBV nuclear antigen 1 in infected thymocytes, assessed by Western blotting with EBV-immune sera. The EBV infection is specific as determined by blocking experiments using anti-CR2 and anti-gp350 antibodies. Finally, virus infection of thymocytes can act synergistically along with interleukin 2 and induce a lymphokine-dependent cellular proliferation. In view of previously reported cases of EBV-positive human T cell lymphomas, the possibility is raised that EBV may be involved in cancers of T lymphocytes that have not been previously appreciated.
The Damus-Kaye-Stansel operation is a useful technique for the treatment of complex cyanotic congenital heart disease when there is obstruction between the systemic ventricle and the aorta. Modifications of the technique include transection of the aorta and the pulmonary artery, anastomosis of the contiguous aortic and pulmonary walls, and connection of the distal aorta to the perimeter of the new bivalved proximal great artery. In addition, the bidirectional cavopulmonary shunt technique can be used with or without the Fontan procedure. Six patients underwent a Damus-Fontan operation, and all survived. Two patients underwent the Damus-cavopulmonary shunt (hemi-Fontan) procedure, and 1 survived. The postoperative status of the 7 survivors is good to excellent. Follow-up ranges from 2 months to 7 1/2 years.
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Since September 1985, 60 cryopreserved homograft valves (12 aortic and 48 pulmonary) have been implanted in the pulmonary position in 56 patients. There were 34 primary operations and 26 reoperations. The ages ranged from 15 days to 22 years; the follow-up ranged from 1 month to 5 1/2 years. The operative mortality was 3.3% (2/56). There were two late deaths (not valve related). Five patients underwent replacement of the homograft; in one patient the homograft was replaced with a heterograft valve. Pathological analysis of the explanted homografts revealed calcification of the wall with satisfactory leaflet function. The leaflets were relatively acellular. No evidence of inflammation or rejection was detected. Four explants were performed for nonvalve-related indications. There are 51 long-term survivors with a homograft in place. Forty-eight are in excellent condition; three are mildly symptomatic (not valve related). Benign pulmonary insufficiency murmurs are present in 29 patients. The presence of trivial or mild insufficiency was independent of the technique of implantation. In general, cryopreserved homograft valves function well in the right ventricular outflow tract. Longer term follow-up is necessary to confirm the superiority of the cryopreserved homograft when compared to the porcine heterograft in the right ventricular outflow tract.
The bidirectional cavopulmonary shunt improves systemic arterial oxygen saturation without increasing ventricular work or pulmonary vascular resistance. Since 1983, 17 patients have undergone a cavopulmonary shunt procedure (five primary operations, 12 secondary operations). Diagnoses were single ventricle complex (n = 4), hypoplastic right heart syndrome (n = 10), and hypoplastic left ventricle (n = 3). Age at primary operation ranged from 3 1/2 to 30 months (median 6 months). Weight ranged from 3.5 to 9.7 kg. Age at secondary operation ranged from 10 months to 14 years (median 15 months). Seven cavopulmonary shunt operations were performed without cardiopulmonary bypass (six via thoracotomy and one via sternotomy) and 10, with cardiopulmonary bypass. All patients in the bypass group had additional procedures: takedown of modified Blalock-Taussig shunt, seven patients; revision of right ventricular outflow tract, four patients; reconstruction of pulmonary arteries, four patients; tricuspid valvuloplasty, one patient; and Damus procedure, one patient. There was one (1/17) operative death (Damus procedure). One patient required early revision. Follow-up ranges from 1 to 53 months (median 23 months). Twelve of 16 had a good to excellent late result, with a rise in mean arterial oxygen saturation from 69% to 83%. Three patients died late (4 to 53 months) (pulmonary vascular disease, pulmonary arteriovenous malformations, and pneumonia, one patient each). There was one late failure (converted to Glenn shunt). The cavopulmonary shunt is an excellent palliative procedure when right atrium-pulmonary artery connection (modified Fontan) must be deferred because of age, weight, or anatomic considerations. Five patients have undergone right atrium-pulmonary artery connection later. In addition, at the time of the modified Fontan operation, the cavopulmonary shunt approach may optimize the anatomic connection (eight additional patients).
Since 1979, 17 infants and children have undergone reoperation for systemic atrioventricular (AV) valve regurgitation 6 weeks to 7 years after repair of congenital heart defects. Prior operations were repair of incomplete or complete AV canal (14 patients), Mustard repair of complex transposition of the great arteries including ventricular septal defect closure (2 patients), or first-stage operation for hypoplastic left heart (1 patient). Age ranged from 6 months to 11 years. In 12 of the 17 patients (10, AV canal; 1, transposition; 1, hypoplastic left heart), valve reconstruction was possible. Operative techniques included a combination of septal cleft approximation, leaflet resection, commissural annuloplasty, or ring annuloplasty. There were no operative deaths, and there were no reoperations in the repair group. The condition of these patients has improved. Follow-up ranges from 1 month to 9 years (mean follow-up, 4.1 years). Five of the 17 patients (4, AV canal; 1, transposition) underwent valve replacement. There were no operative deaths. Follow-up ranges from 3 to 8 years. Three patients later underwent re-replacement of the prosthetic valve; there was 1 late death. The condition of all 4 survivors is improved. Substantial AV valve regurgitation can occur months or years after repair of congenital heart defects. A combination of reconstructive techniques may be useful in preserving native valve function and avoiding systemic AV valve replacement.
Of 581 aortic allografts implanted since 1967, 421 were analyzed for structural deterioration. This series is unique in that it includes patients from the early allograft experience. All allografts were cleanly procured, antibiotic sterilized, and either stored at 4 degrees C for up to 8 weeks or frozen to liquid nitrogen temperatures with cryopreservation to preserve the viable cusp fibroblasts. There were 25 frozen mounted aortic valves with a median time to valve failure of 12.1 years, which was not significantly different from the 12.5-year period for 114 fresh free-sewn aortic valves. The median time to valve failure was 6.6 years for 90 fresh-mounted aortic valves and 8.6 years for 192 fresh-mounted mitral valves (p = 0.05). The difference between all mounted and unmounted grafts was significant (p = 0.0001). In all groups, viable fibroblasts were present in specimens explanted up to 5 years after the operation. All specimens returned after more than 10 years were almost totally acellular. Evidence of increased collagen, suggesting that the fibroblasts survive implantation and then gradually die, was present in all specimens. This series suggests that durability of the unmounted viable allograft for aortic valve replacement is greater than for other types of tissue valves. Pre-mounted allografts for aortic or mitral valve replacement have a median survival of 8 years and are not more durable than other tissue valves.
Clinical and angiographic or autopsy data, or both, on three children with a subdivided left atrium (cor triatriatum) and an associated endocardial cushion defect are reviewed. (One child had ostium primum defect, and two had complete atrioventricular [A-V] canal.) A fourth patient demonstrates the difficulties in differentiating subdivided left atrium from supravalve mitral stenosis in the presence of an endocardial cushion defect. The clinical findings are greatly influenced by the endocardial cushion defect. A pressure gradient between the pulmonary wedge and (left or right) ventricular end-diastolic pressures in patients with an endocardial cushion defect indicates pulmonary venous obstruction and should alert one to the possibility of these combined lesions. The exact diagnosis is made with injections of angiographic contrast medium into the proximal and distal left atrial chambers, to documented the respective relations of the pulmonary veins, left atrial appendage and A-V valves to these atrial chambers. All three patients with an endocardial cushion defect and a subdivided left atrium had an associated patent ductus arteriosus. The common association of subdivided left atrium with intracardiac, pulmonary venous and aortic anomalies is again demonstrated.
The expanded microporous polytetrafluoroethylene (PTFE) 4 mm vascular prosthesis has been used to create a central aortopulmonary shunt in 20 critically ill infants less than 3 weeks old. The infants ranged from 1 to 18 days old (5.25 days), and from 1.5 to 4.0 kg (2.9 kg). Conduit length ranged from 2 to 6 cm (4 cm). Sixteen patients had atresia of the tricuspid or pulmonary valve. There were 6 early deaths (30%), only 1 of which was shunt related. The mean preoperative arterial oxygen saturation was 62% (range, 33 to 80%), and mean postoperative saturation was 87% (range, 78 to 90%). There were 5 late deaths, 1 probably caused by shunt failure. Nine long-term survivors have done well. Follow-up ranges from 1 to 36 months (18 months). Factors influencing conduit function are length, technical considerations, and pulmonary vascular resistance. Late restudy in 5 of 9 survivors confirms patency and demonstrates bidirectional pulmonary blood flow. Since PTFE shunt flow capability is fixed, the infant may require repair or a second shunt within 24 months of the initial procedure.
Mongrel dogs were subjected to hypothermic (28 degrees to 30 degrees C) cardiopulmonary bypass with hemodilution by 50%. In two groups of 8 dogs each, ventricular fibrillation was induced for 60 and 90 minutes, respectively, while the dogs were on bypass. A group of 6 dogs with the heart beating but nonworking served as control. Seven weeks after operation, hemodynamic measurements were made in the survivors (6 in each group) and the heart was fixed by perfusion with glutaraldehyde. Multiple transmural samples were taken from both ventricles. Light microscopy revealed solitary left ventricular scars (0.5 to 3 mm wide) in 2 hearts each from Groups 2 and 3. None of the hearts exhibited diffuse subendocardial fibrosis indicative of healed ischemic injury. All animals were hemodynamically normal. We conclude that in the nonhypertrophied heart, ventricular fibrillation up to 90 minutes with continuous bypass-sustained coronary perfusion (perfusion pressure at or above 70 mm Hg) offers protection from permanent myocardial injury.
We have encountered two cases of late calcification of the porcine heterograft. A patient in chronic renal failure died of sepsis and endocarditis fifteen months after replacement of the mitral and tricuspid valves. At postmortem examination, both heterograft valves exhibited severe calcification and thrombosis. A second patient with rheumatic heart disease and sickle cell disease underwent mitral valve replacement for severe regurgitation. Thirty months later, cardiac catheterization revealed prosthetic valve stenosis. The valve was replaced successfully, and the excised heterograft exhibited severe calcification with restriction of leaflet motion. Although calcification of the porcine heterograft is known to occur in patients with infection or disorders of calcium metabolism, dysfunction of the heterograft is rare in our experience.
One hundred consecutive patients undergoing aorta-coronary bypass grafting (ACBG) alone, without ventricular venting, were prospectively studied to determine the incidence and consequence of perioperative myocardial infarction (PMI) and the clinical variables that were predictive of PMI. Incidence was determined by serial electrocardiography (ECG) 100 patients; serum CK, GOT, and LDH (100 patients). CK isoenzymes (qualitative 100 patients, quantitated 50 patients); vectorcardiography (VCG) (78 patients); and 99mtechnetium pyrophosphate scintigraphy (TcPyp) (52 patients). The incidence of PMI by ECG was 9%; an additional 8% of cases was diagnosed by enzymes alone. The incidence of diagnostic change by VCG was 19% and by scintigraphy, 25%. Using at least one changed variable of the remaining three as the reference standard, the relative sensitivity and relative specificity of given variables in the diagnosis of PMI were as follows: ECG 67% and 100%, respectively; VCG 85% and 94%; scintigraphy 92% and 97%; and serum enzymes 86% and 96%. By univariate analysis, unstable angina was the only significant predictor of PMI. The operative mortality rate was 2% and the mortality rate at 12 months was 5%. There was a significantly greater mortality rate in patients with PMI diagnosed by ECG (p less than 0.01), in patients with unstable angina pectoris before operation (p less than 0.05), and in women (p less than 0.05).
Three consecutive patients with Pseudomonas endocarditis were treated by early operation with no deaths. The indications for operation were severe failure, systemic embolization, and infection refractory to antibiotics. The organism is aggressive, characterized by early invasion of the myocardium. Wide débridement of the anulus is necessary to remove any vegetations or intramyocardial abscessed wall. Because multiple valve infection is common, it is important to evaluate all four cardiac valves at the time of operation. Removing a second rim of the mitral anulus for separate culture at the time of mitral valve replacement may demonstrate the degree to which the valve resection has removed all infection. Early operation is necessary for reinfection of the prosthetic valve; however, metastatic abscess should also be considered in the face of continued signs of infection postoperatively. Patients should receive a 6 week postoperative course of antibiotics which have been shown by in vitro testing to be serum bactericidal in at least a 1:8 dilution. The operative findings of invasion of the myocardium by the organism and the surgical success in this small series have resulted in our recommending earlier operation in patients with these indications.
During a six-year period, 46 severely symptomatic infants (average age, 5.1 months) underwent correction of ventricular septal defect (22 patients), total anomalous pulmonary venous connection (13 patients), and complete atrioventricular canal (11 patients), with the use of surface cooling to 20 degrees C. Cardiac repair was performed during circulatory arrest, and rewarming was performed with a pump oxygenator. Ten patients undergoing repair of ventricular septal defects were studied hemodynamically at 21 degrees C, before repair and at 37 degrees C after rewarming. Heart rate, left ventricular systolic pressure, maximum dp/dt, cardiac index, stroke work, and oxygen consumption were reduced substantially at 21 degrees C. Systemic vascualr resistance was increased at 21 degrees C. All changes were reversible with repair and rewarming. A protocol for hemodilution and crystalloid volume loading was devised to maintain urine output after early patients were noted to demonstrate renal dysfunction. With this protocol, survival rates were 89% for patients with ventricular septal defects, 67% for those with atrioventricular canal defects, and 85% for those with total anomalous pulmonary-venous connection.
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We reviewed current concepts and techniques of cardiac assistance, including orthotopic and heterotopic cardiac allografting. Whereas intraaortic balloon counterpulsation has had the greatest clinical use, other techniques are now becoming available, including the implantable abdominal left ventricular assistance device, and much effort is being expended on the development of artificial hearts and their power sources. Despite the present technical shortcomings, exciting advances have occurred in the clinical management of intractable acute or chronic ventricular failure and cardiogenic shock since the introduction of circulatory assistance in man. The continued development and implementation of these techniques will help reduce the still unacceptably high mortality rate in this group of patients.
Although clinical and hemodynamic stability predicted outcome very well when left ventricular aneurysm was electively resected in 25 patients (95% survival), more discriminate criteria were essential for 20 patients undergoing urgent operation for severe myocardial decompensation (50% survival). Three methods of ventriculographic analysis primarily sensitive to the function of the non-aneurysmal left ventricle were evaluated. These methods separated patients undergoing urgent operation into a population with high operative risk (less than 18% survival) and a population with low operative risk (greater than 82% survival). These criteria also separated 15 patients undergoing operation within three months of myocardial infarction into a group with excellent prognosis (greater than 85% survival) and a group with poor prognosis (less than 15% survival). The high operative risk in patients undergoing urgent operation or operation within three months of myocardial infarction, when non-aneurysmal ventricular function is poor, may be too high; it should be undertaken only under unusual circumstances.