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Biomedical subjects

G Thiene

Publications and source records attributed to G Thiene.

At least 217 records · Page 12Linked to original sources
PubMed1990

Long-term performance of the Hancock porcine bioprosthesis in the tricuspid position. A review of forty-five patients with fourteen-year follow-up.

Because little information is available regarding the clinical performance of the Hancock porcine bioprosthesis (Johnson & Johnson Cardiovascular, King of Prussia, Pa.) implanted in the tricuspid position, we reviewed the long-term follow-up of patients who had tricuspid valve replacement with this device. From March 1970 to December 1983, 45 patients had tricuspid valve replacement, either isolated (seven patients) or combined with replacement of other valves (38 patients) by means of a standard, glutaraldehyde-preserved Hancock porcine bioprosthesis. Follow-up ranged from 0.2 to 14.7 years (mean, 7.6 +/- 3.6 years) and was complete. The late mortality rate was 6.6% +/- 1.6%/pt-yr and the actuarial survival rate at 14 years was 23% +/- 9%. Reoperation because of structural deterioration of the tricuspid, the mitral, or both bioprostheses was performed in nine patients (3.7% +/- 1.2%/pt-yr) from 40 to 177 months (mean, 112 +/- 43 months) and resulted in no deaths. Actuarial freedom from structural deterioration of a Hancock tricuspid porcine bioprosthesis at 14 years is 68% +/- 13%. Morphologic examination of explanted porcine bioprostheses showed that those implanted in the tricuspid position had lower degrees of calcification and less severe structural changes than those simultaneously explanted from the mitral position. We conclude that the Hancock porcine bioprosthesis has an acceptable long-term durability and satisfactory performance after tricuspid valve replacement, and we continue to favor its use in the tricuspid position even in association with mechanical prostheses in the left side of the heart.

Adolescent↗
PubMed1989

Ventricular fibrillation without apparent heart disease: description of six cases.

Since 1977, six patients (five males and one female), aged 14 to 35 years, resuscitated from ventricular fibrillation, were referred to our department for detailed evaluation, after exclusion of major cardiac pathologic conditions. Four patients had a family history of heart disease. Basic ECGs showed sinus rhythm in all of them. PR interval was prolonged in one. Two patients had complete and one had incomplete right bundle branch block. One patient had inverted t waves in V1-3 and late potentials. Three had an upsloping ST-T segment elevation in V1-2. The cardiothoracic index was less than 0.5 in five and 0.50 in one. In one of the five patients studied, the clinical episode of ventricular fibrillation was reproduced by stimulation of the right ventricular outflow tract during electrophysiologic study. Results of cross-sectional echocardiography and angiography showed predominantly structural and wall motion abnormalities of the right ventricle in five patients and slight wall motion abnormalities of the left ventricle in two. Two patients also had mitral and tricuspid valve prolapse. Coronary arteries were normal in all five patients examined. Results of endomyocardial biopsy showed no abnormalities in one patient, fibrosis in two, and fibrolipomatosis in one. Two patients died during follow-up: autopsy was performed in one and results showed right ventricular cardiomyopathy. Thus in five of these selected patients with apparent idiopathic ventricular fibrillation, some abnormalities, predominantly of the right ventricle, were documented only after detailed investigation; however, clinical history and some nonspecific ECG abnormalities were factors in the diagnostic procedure.

Adolescent↗
PubMed1989

Surgical pathology of disease of the mitral valve, with special reference to lesions promoting valvar incompetence.

A consecutive series of 459 mitral valves, which had been surgically excised over a 6-year period, were evaluated by means of macroscopic and histologic study. Of the valves, 379 specimens showed evidence of rheumatic disease (82.6%), 51 were floppy (11.1%), while 29 (6.3%) belonged to a heterogeneous group. The last included cases of ischemic disease (2.4%), infective endocarditis (2.4%), congenital dysplasia (0.9%), rheumatoid arthritis (0.4%), and primary dystrophic calcification (0.2%). Eighty-seven patients had had pure mitral incompetence. Among these, floppiness of the leaflets was the major indication for valvar replacement (58.6%), followed by rheumatic disease (12.7%), ischaemic incompetence (12.7%), and infective endocarditis (11.5%). Particular attention was paid to the clinical-pathological profile of patients with floppy valves as the cause of severe incompetence. This confirmed the prevalence of male patients and the frequent incidence of complications, particularly rupture of tendinous cords (54.9%). A striking difference was also found between the mean age of those patients with and without Marfan's disease (15.3 vs. 53.9 years, P less than 0.001). Although mitral incompetence in the presence of a floppy valve could simply be due to deformity of the leaflets, elongation of the cords and dilatation of the atrioventricular junction, in over half of the cases the precipitating event leading to surgery was rupture of tendinous cords.

Arthritis, Rheumatoid↗
PubMed1989

Endocarditis in an infant causing "tricuspid atresia".

A 3-month-old male infant died of tricuspid valve nonbacterial thrombotic endocarditis complicating disseminated intravascular coagulation. The vegetations were so extensive as to cause tricuspid atresia and led to congestive right ventricular failure terminating in death. The diagnosis was made only at post mortem.

Endocarditis↗
PubMed1989

Morphological survey of a new pericardial valve prosthesis (Pericarbon): long-term animal experimental model.

A long-term experimental morphological study was carried out in 22 adult sheep to evaluate a new pericardial valve prosthesis (Pericarbon), which had been implanted in the tricuspid or mitral position. This prosthetic device differs substantially from others in that its construction design consists of two sheets of glutaraldehyde-fixed bovine pericardium and a low-profile flexible plastic stent (Delrin) covered by a pyrolytic carbon coated dacron fabric; one pericardium sheet forms the three cusp valve and is sutured to the second, which lines the inner surface of the plastic stent. Twenty animals were sacrificed at fixed intervals, while 2 are still living at about 3 years post-surgery. Tricuspid explants (mean duration, 295 days) showed significant fibrous sheathing and a mean calcium X-ray score of 1.75. Mitral medium-term explants (mean duration, 325 days) had fairly well preserved pliability and a mean calcium X-ray score of 2.5. Long-term explants (mean duration, 467 days) were all stiffened by calcification (mean score, 3.75). None of the explants had tears or perforations. Medium or long-term mechanical failure was not observed. A significant host tissue reaction took place in the tricuspid but not in the mitral position. Calcification mainly involved the collagen fibres and increased progressively with time. Ultrastructural studies invariably disclosed fair preservation of graft tissue structures, surface reendothelization and initial nuclei of calcification within the collagen fibres. These morphological findings confirm the potential advantages of this new prosthetic device and warrant long-term clinical trials to test its actual durability.

Animals↗
PubMed1989

Great saphenous vein protection in arterial reconstructive surgery.

An original method of great saphenous vein bypass protection during reconstructive arterial surgery is described. The use of a reinforced prosthetic support (Ringed PTFE), surrounding the vein, avoids possible compression by anatomical structures and strangulation by scar tissue after reoperation. This technique can also prevent eventual dilatation of the vein graft. Since 1981, this technique has been successfully applied to 30 selected patients. On the basis of clinical experience, the authors conclude that this method is safe and effective, and may increase the long-term patency rate of saphenous vein grafts.

Blood Vessel Prosthesis↗
PubMed1989

Right ventricular dysplasia: a familial cardiomyopathy?

268 preselected subjects were extensively studied and the diagnosis of right ventricular dysplasia (RVD) was made in 108 living and 18 deceased patients, 35% of cases being familial. Subsequently we studied 72 subjects from nine families in which a case of sudden death had occurred with the autoptic diagnosis of RVD. In 42 out of 72 cases the autoptic (11 patients), clinical-echocardiographic (30 patients) and haemodynamic (15 patients) data supported the diagnosis of RVD. In all but one deceased patient, death was sudden, while in all the living family members we observed ventricular arrhythmias, mostly with left bundle branch block morphology. Both manifest and concealed forms were documented with polymorphic presentation and with clinical-pathologic findings similar to the non-familial RVD cases. This study confirms the presence of a familial form of RVD that is probably more frequent than previously thought. Preliminary data seem to indicate an autosomal dominant inheritance with incomplete penetrance and variable expression.

Arrhythmias, Cardiac↗
PubMed1989

Relevance of subtle echocardiographic findings in the early diagnosis of the concealed form of right ventricular dysplasia.

Right ventricular dysplasia (RVD) is an important cause of arrhythmic sudden death in young people. Echocardiographic criteria suggestive of RVD were: dilation of RV, localized bulge and dyskinesia of the inferobasal wall, structural changes of the moderator band, isolated enlargement of RV outflow tract, apical dyskinesia and trabecular disarrangement. Among 136 subjects 'at risk of high incidence of RVD', 40 had a suggestive echocardiogram. 90% of these showed lipomatous transformation at biopsy and/or developed serious ventricular arrhythmias during a mean follow-up of 42 months. Thus, echocardiography is a potent method in detecting myocardial pathology due to RVD.

Adolescent↗
PubMed1989

Contribution of cross-sectional echocardiography to the diagnosis of right ventricular dysplasia at the asymptomatic stage.

The value of cross-sectional echocardiography in the early diagnosis of right ventricular (RV) dysplasia in asymptomatic patients has been assessed. Criteria that defined RV dysfunction and structural abnormalities were developed from 38 normal subjects. Of 136 patients admitted into the study program, 40 (29.4%) had an echocardiogram suggestive of RV dysplasia using the following criteria: mild dilatation of the right ventricle (normal range defined as the 95% confidence limit of the values in the control group); localized bulge and dyskinesia of the infero-basal wall; structural changes of the moderator band; isolated enlargement of RV outflow tract; apical dyskinesia and trabecular disarrangement. Holter monitoring and a maximal exercise stress test at entry into the study and during the follow-up (mean 42, range 18-82 months) demonstrated serious ventricular arrhythmias, and RV endomyocardial biopsy confirmed the diagnosis of RV dysplasia in most of these patients, characterized by an electrical instability of RV myocardium (82.5%). During the follow-up, a marked enlargement of RV cavity appeared in three other patients, and RV endomyocardial biopsy demonstrated the typical findings in all patients.

Adolescent↗
PubMed1989

Evaluation of Pericarbon valve prosthesis: in vitro, ultrastructural, and animal studies.

Pericarbon, a new generation pericardial valve, is characterized by a single, three cuspal shaped pericardium sheet, which is sutured to a second sheet lining the inner surface of the plastic, low profile stent. A coating of hemocompatible carbon film covers all the exposed, nonbiological surfaces. Optimal preservation of collagen and graft cells is achieved by fresh tissue glutaraldehyde fixation and cusp shaping without mold. Accelerated fatigue testing showed a duration of over 150 million cycles, a figure much higher than that observed when current pericardial and porcine valves were tested with the same apparatus. Results of long-term (greater than 7 months, average 10.5) implantation in 20 sheep (13 mitral, 7 tricuspid) disclosed no case of mechanical failure, mild to moderate primary calcification in older explants, and significant fibrous tissue overgrowth only in the tricuspid position. Transmission electron microscopy studies revealed collagen and elastic fiber integrity, no significant plasma protein insudation, and well-preserved graft cells. Re-endothelialization by host cells was a regular finding on scanning electronic microscopy. Early ultrastructural nuclei of calcification were seen mostly on collagen fibers. Pericarbon presents basic changes in pericardial valve design, and optimal morphological preservation is obtained after industrial processing. Accelerated fatigue tests in vitro show long duration. At medium long-term animal experimental follow-up, mechanical failure was not observed; significant host tissue reaction occurred in the tricuspid but not in the mitral position; primary calcification increased progressively with time and involved mainly collagen fibers.

Animals↗
PubMed1989

Fatal asthma in a young patient with severe bronchial hyperresponsiveness but stable peak flow records.

We report the sudden death of a 16 yr old boy with asthma. At presentation, the patient had symptoms of active asthma, mild bronchoconstriction, severe airway hyperresponsiveness to methacholine, and increased variability of peak expiratory flow records. After the patient was placed on inhaled beclomethasone (1 mg b.i.d preceded by inhaled fenoterol 0.4 mg b.i.d) he rapidly felt better, lung function improved, but airway responsiveness remained severe. Four months later, on the day he died, he was well until a fatal attack of asthma occurred around midnight without identifiable precipitating factors. Taken to hospital, he was dead on arrival. Necroscopy and microscopy showed the characteristic features of asthma death. This case report suggests that; a) asthma death may occur suddenly and unexpectedly; b) asthma death may not be prevented by long-term treatment with high-dose inhaled beclomethasone; c) severe bronchial hyperresponsiveness, even in the presence of stable peak flow records, may identify asthmatic patients at risk of sudden death.

Adolescent↗