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Biomedical subjects

G Thiene

Publications and source records attributed to G Thiene.

At least 253 records · Page 14Linked to original sources
PubMed1987

Post bending of the polypropylene flexible stent in mitral Hancock bioprostheses.

The occurrence of stent post deformity was investigated in 38 consecutive, polypropylene flexible-stented Hancock porcine bioprostheses (PB) recovered from the mitral position because of early postoperative death or late tissue failure. The degree of deformity was assessed for each explant by calculating the triangular area obtained by projecting the apex of the stent posts on a plane and comparing it with the same area calculated for unimplanted PBs of comparable size. A significant stent deformity (reduction of the triangular area greater than 40%) was observed only in 6 PBs explanted because of tissue failure after a mean function time of 69.6 +/- 28 months. In these PBs, scanning electron microscopy of the bare surface of the stent at the point of maximal flexion showed cracks 0.7-1 microns large, which represent the morphological substrate of the so-called "creep" of polypropylene. Inward stent post bending may occur after implantation in mitral PBs and when severe, it corresponds to a definite ultrastructural plastic deformity of polypropylene.

Animals↗
PubMed1987

Long-term durability of the Hancock porcine bioprosthesis following combined mitral and aortic valve replacement: an 11-year experience.

Long-term evaluation of patients undergoing combined mitral and aortic valve replacement (MVR + AVR) with a porcine bioprosthesis provides the opportunity for a direct comparison of the durability of the mitral versus the aortic porcine bioprosthesis in the same patient. From 1970 to 1983, 71 patients underwent MVR + AVR with Hancock porcine bioprostheses. There were 46 men an 25 women ranging in age from 21 to 64 years (mean, 47.5 +/- 5 years). Sixteen patients (22.5%) died at operation. The survivors were followed from 0.2 to 11.5 years (mean, 5.7 +/- 3 years). Duration of follow-up was 313 patient-years and was 100% complete. Overall late mortality was 6.7 +/- 1.4% per patient-year (linearized incidence), and actuarial survival was 54.2 +/- 8% at 11 years. Endocarditis occurred in 4 patients (linearized incidence of 1.3 +/- 0.6% per patient-year); thromboembolic events were sustained by 4 patients (linearized incidence of 1.3 +/- 0.6% per patient-year); the event was fatal in 1 patient. Actuarial freedom from thromboembolism was 90 +/- 4.8% at 11 years. Reoperation for primary tissue failure was performed in 11 patients (linearized incidence of 3.5 +/- 1% per patient-year) with no deaths; in 7 patients both bioprostheses were explanted, and in 4, only the mitral bioprosthesis was replaced. The durability of explanted aortic and mitral porcine bioprostheses was not significantly different, and the evaluation of seven pairs of explanted aortic and mitral bioprostheses showed similar amounts of calcification. Actuarial freedom from reoperation because of primary tissue failure was 44.6 +/- 13.7% at 11 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1987

The ventricular septal defect in complete transposition of the great arteries: pathologic anatomy in 57 cases with emphasis on subaortic, subpulmonary, and aortic arch obstruction.

Fifty-seven heart specimens with complete transposition (concordant atrioventricular and discordant ventriculo-arterial connections) and ventricular septal defect were reviewed to establish the spectrum of morphology of the ventricular septal deficiency and to correlate the type of defect with presence of subarterial and aortic arch obstruction. The ventricular septal defect was single in 52 cases (27 perimembranous and 25 muscular) and multiple in five. A normal alignment between the outlet component and the rest of the muscular septum was present in 18 cases (10 perimembranous, five muscular, and three multiple). The defect was the consequence of septal malalignment in the other 39 specimens; 29 with rightward and 10 with leftward displacement of the outlet septum. Rightward displacement led to perimembranous defects in 16 cases and muscular defects in 12. In another instance, a perimembranous malalignment defect was associated with a muscular inlet defect. Subaortic stenosis due to either deviation of the outlet septum or prominence of the ventriculo-infundibular fold and septoparietal trabeculations was observed in 14 cases. Leftward displacement of the outlet septum was associated with one perimembranous and eight muscular defects and with multiple (muscular outlet plus muscular inlet) defects in another case. Of these, five cases showed subpulmonary stenosis. Aortic arch obstructions were present in 19 cases; 14 showed rightward malalignment of the outlet septum, which produced subaortic stenosis. These findings suggest two things: Unlike the situation in hearts with "normally related" great arteries, most defects in complete transposition result from malalignment of the outlet septum, with many being of the muscular type. Rightward or leftward displacement of the outlet septum frequently results in subaortic or subpulmonary stenosis, respectively. Aortic arch obstructions, although frequent, are not always associated with subaortic stenosis.

Adolescent↗
PubMed1987

Conjoined twins, right atrial isomerism, and sequential segmental analysis.

Three cases of twins conjoined across the chest were examined. In one set, one twin showed right atrial isomerism and the other showed the usual atrial arrangement. The other two sets showed the usual atrial arrangement in both twins. The associated cardiac anomalies were diverse, ranging from atrioventricular septal defects to absent atrioventricular connections. Sequential segmental analysis was used successfully in each case to classify the complex cardiac anomalies. The first step was the recognition of the atrial arrangement. This was easily achieved despite the complexity of the intracardiac morphology.

Female↗
PubMed1987

Early mechanical failures of the Hancock pericardial xenograft.

From August 1981 to July 1984, a total of 97 Hancock pericardial xenografts were implanted in 84 patients, whose ages ranged from 13 to 75 years (mean 55.7 +/- 13). Mitral value replacement was performed in 17, aortic valve replacement in 54, and mitral-aortic valve replacement in 13. Operative survivors were reevaluated from July to September 1985. Cumulative duration of follow-up is 167 patient-years (range 0.5 to 4.1 years), and follow-up is 99% complete. The overall late mortality (at 4 years) is 3.6% +/- 1.4% per patient year, and the actuarial survival rate is 95.4% +/- 3% for aortic valve replacement, 74.7% +/- 16.5% for mitral valve replacement, and 67.1% +/- 20.7% for mitral-aortic valve replacement. One patient sustained a thromboembolic event after mitral valve replacement, but no such complications occurred after aortic or mitral-aortic valve replacement. Actuarial freedom from embolism at 4 years is 100% for aortic and mitral-aortic valve replacement and 93.3% +/- 6.4% for mitral valve replacement. Reoperation for Hancock pericardial xenograft dysfunction was performed in seven patients (five aortic and two mitral-aortic). In the aortic valve replacement group the causes were endocarditis in one, paravalvular leak in one, and primary tissue failure in three; all survived reoperation. The two patients with mitral-aortic valve replacement required reoperation because of primary tissue failure of both Hancock pericardial xenografts, and one died. All values explanted because of primary tissue failure showed commissural tears causing severe prosthetic regurgitation. Calcium deposits were severe in one and mild but unrelated to the cusp rupture in another. Collagen disarray was seen only at the site of the tears, whereas the collagen structure was well preserved in the intact parts of the cusps. Four patients with aortic valve replacement and one with mitral valve replacement show evidence of Hancock pericardial xenograft failure and are awaiting reoperation. The actuarial freedom from primary tissue failure at 4 years is 74.3% +/- 9.8% for aortic and 78.9% +/- 13.2% for mitral Hancock pericardial xenografts. At medium-term follow-up, the Hancock pericardial xenograft has shown poor durability and an extremely high rate of early mechanical failure, especially in the aortic position. These observations suggest the need for a close follow-up of Hancock pericardial xenograft recipients and possibly elective reoperation in asymptomatic patients with clinical evidence of prosthetic failure. These results have led us to discontinue the clinical use of this pericardial xenograft.

Adolescent↗
PubMed1987

Dissecting cuspal hematomas. A rare form of porcine bioprosthetic valve dysfunction.

Large dissecting cuspal hematomas (DCHs) were present in six (3%) of 193 porcine bioprostheses (PBs) explanted at reoperation. In four mitral PBs, the DCHs contributed to valve dysfunction; in one aortic PB, DCH was the only determinant of failure, causing stenosis by cusp thickening and rigidity. In another mitral PB, DCHs were occasionally found in the setting of valve incompetence due to commissural tears. While confirming that DCHs are a potential but infrequent cause of PB failure, these observations demonstrate that they may involve PBs implanted both in mitral and aortic position and might be a complication of anticoagulation.

Adult↗
PubMed1987

[Another case of juvenile sudden death caused by anomalous origin of the right coronary from the left anterior sinus of Valsalva].

A second case of sudden death during athletic activity, due to anomalous origin of the right coronary artery from the left anterior sinus of Valsalva, is presented. Post-mortem examination disclosed widespread myocardiosclerosis involving the subepicardial layers of the posterior wall of the left ventricle. Submaximal exercise testing had been performed to evaluate the presence of a ventricular extrasystole on a basal ECG, but no significant ischemic alterations of the ST tract had been detected. This case proposes once again the uncertainties regarding the diagnostic sensitivity of the protocols for competitive sport fitness in revealing latent chronic ischemia.

Adult↗
PubMed1986

Rhythm and conduction disturbances in isolated, congenitally corrected transposition of the great arteries.

The incidence and types of rhythm and conduction disturbances in 11 male and 6 female patients with congenitally corrected transposition of the great arteries and no other intrinsic complicating anomalies were studied. Patient age ranged from 5 to 54 years; follow-up ranged from 5 to 37 years. Surface electrocardiograms were recorded in each patient; 15 also underwent 24-hour Holter monitoring and 10 underwent electrophysiologic study. The conduction system of a 54-year-old woman who died suddenly, with complete atrioventricular (AV) block since age 30 years, was studied by serial histologic sections. Fifteen patients were asymptomatic and 2 reported repeated episodes of palpitation since childhood. Ten patients presented with a normal PR interval and 2 with first-degree AV block (12%). Five patients had complete AV block (29%), but none had had it at birth; first- and second-degree AV block preceded complete AV block in 2 patients. The morphologic pattern and duration of QRS suggested a junctional rhythm in 4 patients and an idioventricular pacemaker in 1 patient. Electrophysiologic studies confirmed that the complete AV block site was supra-Hisian in 2 patients and proximal to the His bundle bifurcation in 1 patient. However, histologic investigation disclosed fibrosis and disruption of the proximal nonbifurcating His bundle in the patient who died suddenly. In 2 patients with recurrent supraventricular tachycardia, electrophysiologic studies suggested reentry through James fibers (or dual AV nodal pathway) in 1 and the presence of a left lateral accessory AV pathway in the other. Holter monitoring showed a high incidence of ventricular arrhythmias.

Adolescent↗
PubMed1986

Anatomical-echocardiographic correlations in pulmonary atresia with intact ventricular septum. Use of subcostal cross-sectional views.

Cross-sectional echocardiographic images from 26 patients presenting pulmonary atresia with intact ventricular septum were compared with anatomical findings in specimens having the same anomaly. The echocardiographic study was based on a subcostal approach using oblique projections, and specimens were cut in the same planes. Patients were classified into three groups. In the first group the morphologically right ventricle was represented by all of its three component parts: inlet, trabecular and outlet (12 cases). The second group was made up of patients with overgrowth of the apical component. Consequently the right ventricle had only two effective components: inlet and outlet (6 cases). In the third group, muscular overgrowth of both outlet and apical portions meant that the right ventricle was represented only by an inlet portion (8 cases). The good morphologic assessment and correlation with anatomic cuts, obtained in particular by using the "right oblique equivalent" view can avoid invasive study in this malformation prior to palliative surgery.

Angiocardiography↗
PubMed1986

Fatal paroxysmal supraventricular tachycardia in an infant.

A 37-day-old infant, without associated congenital anomalies, died following a 48-hour episode of supraventricular tachycardia. The histopathologic findings of nodoventricular and fasciculoventricular Mahaim's fibers in a setting of persistent fetal dispersion were consistent with an anatomic substrate for a reentry circuit at the specialized A-V junction.

Electrocardiography↗
PubMed1986

[Hypertrophic cardiomyopathy and juvenile sudden death. A clinical case and re-evaluation of the problem].

A 29-year-old man with non-familiar hypertrophic cardiomyopathy died suddenly. The patient experienced recurrent episodes of palpitation both at rest and during exercise. M-mode and 2-D echocardiograms showed severe asymmetric septal hypertrophy (IVS/LVPW ratio 3:1) and systolic anterior motion of anterior leaflet of the mitral valve. The ECG demonstrated deep "Q" waves from the inferior leads and inverted "T" waves in V1 to V6, but failed to register arrhythmias. Holter monitoring had been planned in order to achieve information for pharmacologic therapy, but unfortunately the patient died during the stand-by. Postmortem examination showed severe asymmetric septal hypertrophy with fibrosis and wide-spread "myocardial disarray".

Adult↗
PubMed1986

Aortic root pathology and sudden death in youth: review of anatomical varieties.

Post-mortem findings in 6 young people who died suddenly are reported; ages ranged from 9 to 28 years (average 17). All had practised sport, and 2 died during strenuous exercise. Three cases had been under observation for mild aortic stenosis, while no cardiovascular disorders had been suspected in the others. Autopsy studies ruled out coronary atherosclerotic diseases, myocardial disarray or myocarditis as well as any extracardiac cause of death in every case. A stenotic bicuspid aortic valve was found in 2; supravalvar aortic stenosis and incomplete isolation of the left coronary ostium in 1; anomalous origin of the right coronary artery from the left sinus of Valsalva in 1, and dissecting aneurysm of the ascending aorta in 2. These findings show that congenital anomalies of the aortic root (valve, wall, coronary ostia) are at risk for abrupt complications. Early detection of this frequently silent pathology by non-invasive techniques is mandatory to avoid effort and sporting activities and thus prevent sudden death.

Adolescent↗
PubMed1986

[Complete atrioventricular block and sudden death in isolated corrected transposition].

The rate of av conduction disturbances in corrected transposition of the great arteries is high, possibly as consequence of mechanical injury by ventricular output along with the mis-positioned specialized av junction. A sudden death occurred in a 54 year old female affected by a chronic "idiopathic" complete av block, who showed at autopsy a heart with av and ventricular arterial discordance in the absence of other anomalies (isolated corrected transposition). The cardiac arrest had the ecg features of ventricular fibrillation, preceded by sustained ventricular tachycardia. Histologic study of the conduction system by serial sections confirmed the anterior position of the connected av node, with a long subendocardial course of the bundle in the pulmonary outflow tract. The histologic basis of the block consisted of sclero-atrophy of the common bundle, quite similar to the substrate of acquired av block in heart with normal connections. Possible etiologies, responsible of the relation between the av block and onset of ventricular arrhythmias, are discussed.

Death, Sudden↗
PubMed1986

[Tachycardia and ventricular fibrillation in the arrhythmogenic right ventricle (arrhythmogenic dysplasia of the right ventricle). Clinical and electrocardiographic spectrum].

In this paper we report the arrhythmias recorded on basal ECG, on Holter monitoring or on exercise test, in 32 pts affected by arrhythmogenic right ventricle (ARV). A sustained ventricular tachycardia (VT) was present in 11 pts a non sustained VT in 15 pts, a slow VT in 2 pts, a ventricular fibrillation (VF) in 3 pts and both sustained VT and VF in 1 pt. All but 1 case of sustained VT showed a LBBB like pattern. The heart rate during VT ranged between 170 and 280 beats/min. The frontal axis of the VT showed a wide range of deviation. Among non sustained VT, 9 cases had LBBB like pattern and 6 cases had polymorphic configuration. The 2 cases of slow VT showed LBBB like pattern with right axis deviation. A comparison between ventricular arrhythmias and RV impairment was made. The data obtained suggest that the effort plays an important role in the induction of VT in pts with localized RV impairment. In conclusion a wide spectrum of ventricular tachyarrhythmias is present in the ARV. Probably the RV "arrhythmogenic" zones and the electrophysiological mechanism causing the arrhythmias are various.

Adolescent↗