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Biomedical subjects

G Thiene

Publications and source records attributed to G Thiene.

At least 307 records · Page 17Linked to original sources
PubMed1984

The surgical anatomy of hearts with no direct communication between the right atrium and the ventricular mass--so-called tricuspid atresia.

Seventy-six hearts were studied having no direct communication between the right atrium and the ventricular mass. The different cardiac chamber combinations producing so-called "tricuspid atresia" were considered. The nature of the atrioventricular valve atresia, the morphology of the ventricular mass, the size and position of the interventricular communication, the ventriculoarterial connection, and the presence of subarterial outflow tract obstruction were all analyzed. The majority of cases were of the "classical" type, i.e., absent right atrioventricular connection with the left atrium connected to the left ventricle. In another group there was absence of the right atrioventricular connection but the left atrium drained into the morphologically right ventricle, which was left-sided. In a third group both atrial chambers connected with the ventricular mass but some structure, an imperforate valve or muscular partition, completely blocked the flow pathway through the right side of the heart. All the hearts described are candidates for the Fontan procedure with either an atrioventricular or an atriopulmonary conduit. The surgical options would not be affected by the observed variability at the atrioventricular junction but would be dictated by the feasibility of incorporating the subpulmonary ventricle within the pulmonary circulation.

Heart Atria↗
PubMed1983

Cardiac conduction system abnormalities as a possible cause of sudden death in young athletes.

Histologic examination of serial sections of the conduction system of the hearts of three young persons who died suddenly while engaged in active sports was performed. In no case were electrocardiogram tracings available. One patient, an 11-year-old girl, had micro-Ebstein's anomaly of the tricuspid valve associated with a septoseptal Kent fascicle through a wide gap of the central fibrous annulus and upper Mahaim fibers. Another patient, a 24-year-old football player, had a focal, 75 per cent obstructing atherosclerotic plaque in the proximal descending coronary artery, with scattered band necrosis and patchy myocardial fibrosis; upper and lower Mahaim fibers joined the atrioventricular node and the left bundle branch with the crest of the interventricular septum. The third patient, a 26-year-old cycling champion, had a conspicuous atrial fascicle of ordinary and transitional myocardium bypassing the atrioventricular node to anastomose with the His bundle (James accessory atrioventricular pathway). These findings indicate that atrioventricular conduction system abnormalities may play a fatal arrhythmogenic role in sudden death and raise questions regarding the prevention of electrical instability in young people engaged in active sports.

Adult↗
PubMed1983

Accessory tricuspid valve tissue causing obstruction of the ventricular septal defect in tetralogy of Fallot.

Among 61 heart specimens of tetralogy of Fallot with or without pulmonary atresia, four presented with an accessory tricuspid valve leaflet. This structure caused partial or almost complete obstruction of the ventricular septal defect. Depending on the morphology, the accessory tissue was classified into "mobile" or "fixed" types. The "mobile" variety was tethered by long chordae tendineae which permitted a wide excursion of the leaflet through the ventricular septal defect into the left ventricular outflow tract where it represented a potential cause of obstruction. The "fixed" variety was attached to the edges of the defect by short chordae which reduced considerably its movements. This type created a fixed obstruction of the ventricular septal defect without involving the subaortic left ventricular outflow tract. The precise morphology of the accessory tricuspid valve tissue is of considerable surgical significance. When mobile, the tissue must be resected at the time of surgical repair. When fixed it can be used as a suture anchorage during closure of the ventricular septal defect.

Adult↗
PubMed1983

Glutaraldehyde-preserved porcine bioprosthesis. Factors affecting performance as determined by pathologic studies.

The causes of porcine valve failure were evaluated pathologically in 129 bioprostheses (BP) removed at surgery or necropsy. Fifty-one BP had been in place for less than two months (early explants); most of the complications of this group were observed in the mitral position: left ventricular outflow obstruction (43 percent), thrombosis (23.5 percent), myocardial dysruption (20 percent), cardiac rupture (10 percent), and perivalvular leak (3.5 percent). Among the 78 explants in place for more than two months (late explants), 66 had evidence of dysfunction. Calcification was the leading cause of failure (46 percent), followed by thrombosis (17 percent), endocarditis (12 percent), fibrous tissue overgrowth (10 percent), perivalvular leak (9 percent), and primary cusp tears (6 percent). Calcific degeneration is a hallmark of the phenomenon of biodegradation, and experimental animal models are encouraged since they may represent the clue to preventing calcification and therefore enhancing performance and durability of the porcine BP.

Adolescent↗
PubMed1983

Cardiac ultrastructure in primary restrictive cardiomyopathy.

A five-year clinical follow-up and the results of myocardial biopsies are described in a patient with primary restrictive cardiomyopathy. Histologic examination of a right ventricular endomyocardial biopsy taken early in the course of the illness was not contributory. Histologic examination of a left ventricular endomyocardial biopsy five years later showed hypertrophy and disarray of myocytes, thickening of the endocardium, and interstitial fibrosis. Connective tissue was compact and regularly oriented in the endocardium, but tangled and irregularly oriented in the interstitium. It is concluded that the irregular network of collagen fibrils and elastic fibers limits diastolic relaxation and prevents ventricular dilatation; that the coexisting hypertrophy results from an attempt to maintain normal pump function; and that the myocyte disarray is a consequence of abnormal mechanical forces generated under conditions of severe fibrosis.

Biopsy↗
PubMed1982

Pregnancy in patients with a porcine valve bioprosthesis.

Seven patients who became pregnant after valve replacement with a Hancock bioprosthesis were followed up during 8 pregnancies. Six had undergone isolated mitral valve replacement, and 1 had mitral and aortic valve replacement. Their age at the time of operation ranged from 14 to 31 years (average 24); delivery occurred 21 to 88 months (average 51.3) after valve replacement. All women were in sinus rhythm at the time of gestation, and administration of oral anticoagulants was avoided in all. No embolic episodes occurred either after operation or during pregnancy, labor, or puerperium. The only major complication during pregnancy was cardiac failure in 1 patient, associated with onset of atrial fibrillation. Four women had vaginal delivery and 3 required cesarean section. All but 1 delivered a normal, healthy baby. One premature infant died soon after birth because of respiratory distress. No maternal or fetal hemorrhagic complications were observed. One patient died 3 months after delivery in severe heart failure caused by diffuse calcification of both mitral and aortic xenografts. Another women underwent successful reoperation soon after the second pregnancy because of calcific stenosis of the mitral porcine valve. It is concluded that (1) bioprosthetic valves can be considered the most suitable devices employed in women of childbearing age because anticoagulants can be avoided, therefore eliminating the risks related to inappropriate administration of oral anticoagulants as well as the hazards associated with the potential teratogenic effect of coumarin drugs; and (2) pregnancy might favor calcification of porcine heterografts, leading to bioprosthetic failure. Until further data are available to support this suspicion, close clinical and echocardiographic follow-up study of these patients is recommended after pregnancy.

Adolescent↗
PubMed1982

Evidence of impending embolization of a calcific cusp fragment from a mitral porcine xenograft.

The use of porcine bioprostheses has been associated with a low rate of embolic complications. The case here presented provides evidence that systemic emboli in porcine valve recipients may not necessarily be due to intracardiac or prosthetic thrombosis, but to detachment and migration of fragments of degenerated cusp tissue. Therefore, urgent assessment of xenograft function is recommended in patients with a porcine bioprosthesis who experience embolic episodes late postoperatively.

Bioprosthesis↗
PubMed1982

Complete transposition of great arteries with coarctation of aorta.

Complete transposition of the great arteries with ventricular septal defect and coarctation or atresia of the aortic arch is a relatively rare anatomoclinical entity and in general not well understood. This association accounted for six out of 50 cases (12%) of our clinical experience and six out of 64 cases (9%) of the post-mortem series of complete transposition. Relevant clinical manifestations were cyanosis, early and pronounced congestive heart failure, with a decrease in amplitude of femoral pulses and, in the most severe cases, isolated left ventricular hypertrophy on the electrocardiogram. Inlet or outlet right ventricular obstruction and pulmonary artery dextroposition are the pathological substrates of unequal partitioning of the blood stream in favour of the pulmonary artery and ductus arteriosus, probably accounting for fetal underdevelopment of the aortic arch. The medical and surgical prognosis of these cases is definitely poor.

Aortic Coarctation↗
PubMed1982

Postoperative pathology of congenital heart disease. I. Complete atrio-ventricular canal.

The postoperative pathology observed in 17 patients with complete atrioventricular canal, who died following total correction is described. In 3 patients, in whom valve replacement was necessary, the death was due to late prosthetic dysfunction. Out of 14 patients who underwent plastic repair, 4 died from undetected residual cardiac anomalies, which in 2 cases were associated with pulmonary obstructive vascular disease, 3 from unexplained myocardial infarction, 3 from inadequate postoperative care and 4 from pulmonary obstructive vascular disease which presented as an isolated finding. An analysis of the incidence of pulmonary obstructive vascular disease in these patients disclosed that it can develop before one year of age in some patients with Down syndrome.

Abnormalities, Multiple↗
PubMed1982

Postoperative pathology of complete atrioventricular defects.

Necropsy data on 15 patients, who died after operations for complete atrioventricular defect (CAVD), were reviewed in order to analyze the possible determinants of death. Two infants had undergone a palliative procedure--pulmonary artery banding (Group I); three patients had had prosthetic replacement of one or both atrioventricular (AV) valves (Groups II); and the remaining 10 had had conservative repair with plastic reconstruction of the AV valves (Group III). The most notable pathological findings related to death were as follows: Group I, left ventricular hypoplasia in both infants; Group II, prosthetic dysfunction in all patients; Group III, extracardiac diseases in two-patients and cardiac lesions in six. In Group III severe pulmonary vascular obstructive disease (PVOD) was observed as an isolated finding in two patients and in combination with residual intracardiac anomalies in another two. Analysis of the incidence of PVOD demonstrated that irreversible changes may occur within the first year of life in babies with Down's syndrome, and that these changes well correlate with the calculated pulmonary vascular resistance (PVR) values. From the results of this study we have reached the following conclusions: (1) Prosthetic valve replacement has to be avoided because of a high incidence of prosthesis-related complications and the effectiveness of conservative repair; (2) residual untreated anomalies may affect the outcome of operation and should be accurately recognized and weighted preoperatively; (3) PVOD can occur in CAVD even before the first year of life and can be reliably assessed by the measurement of PVR. High degrees of PVOD frequently interfere with the surgical success, particularly when residual intracardiac anomalies are present. Therefore, we suggest that surgical correction be planned, when indicated, during the first 6 months of life.

Adolescent↗
PubMed1982

Cusp disruption by massive lipid infiltration. A rare cause of porcine valve dysfunction.

A 68-year-old man underwent reoperation because of severe incompetence of a mitral valve xenograft, 96 months following implantation. Gross examination of the device showed yellow spots on the cusps, suggesting lipid infiltration, and a torn commissure. Plasmatic cholesterol and lipiprotein levels were normal. X-ray examination of the explants showed no calcific deposits. Histologic and electron microscopic studies disclosed massive accumulation of lipid clefts and droplets, predominantly at the level of the tear; focal loss and detachment of the endothelial lining and scanty porcine fibroblasts and collagen bundles with preserved periodicity were also noted. Primary disruption of porcine valvular bioprostheses without significant calcifications or collagen breakdown is uncommon. In the present case, lipid accumulation was the main determinant of tissue failure.

Aged↗