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Biomedical subjects

E Bos

Publications and source records attributed to E Bos.

At least 55 records · Page 3Linked to original sources
PubMed1995

Pulmonary homograft insertion after repair of pulmonary stenosis.

Although the results of intracardiac repair for pulmonary stenosis or atresia are generally good, some patients develop symptoms due to to pulmonary regurgitation and right ventricular dilatation. Implantation of a pulmonary homograft may have a beneficial effect on these symptoms. Twenty-seven patients with symptoms due to pulmonary regurgitation and right ventricular dilatation were reoperated. The indication for surgery was dyspnea in 19, arrhythmia in five and both symptoms in three patients. The arrhythmia was supra-ventricular in four, ventricular in two and both supra-ventricular and ventricular in another two patients. A cryopreserved pulmonary homograft was implanted in the right ventricular outflow tract. Mean interval between intracardiac repair and homograft implantation was 15.6 years. Mean age at homograft implantation was 23.0 years. Concomitant procedures were performed in 18 patients. There were two early deaths (7%). Replacement of the homograft was necessary in one patient, 21 months after insertion. This patient had residual pulmonary stenosis immediately after surgery. On mid-term follow up (mean 36 months) all patients with dyspnea as indication for operation improved, except one with right and left ventricular dysfunction. Only two of eight patients with arrhythmia improved. On echocardiography, pulmonary regurgitation decreased in all patients. Right ventricular dilatation decreased in only 14 patients (52%). We conclude that pulmonary regurgitation after transannular patching can be treated with implantation of a cryopreserved pulmonary homograft with acceptable mortality and low morbidity. Clinical improvement results from reduction of the right ventricular volume overload rather than from decline in right ventricular dilatation. Arrhythmia as the only indication for operation is controversial.

Adolescent↗
PubMed1994

Long-term follow-up after surgical closure of ventricular septal defect in infancy and childhood.

OBJECTIVES: The purpose of this study was to assess the health-related quality of life of patients who underwent surgical closure of a ventricular septal defect at a young age between 1968 and 1980. BACKGROUND: Since the beginning of open heart surgery for congenital cardiac malformations, the surgical techniques have continually improved. As a result, even infants have become eligible for surgical repair. Long-term follow-up data are not available on the health-related quality of life of nonselected patients after surgical repair at a young age. We therefore conducted a follow-up study of 176 infants and children consecutively operated on in one institution between 1968 and 1980. METHODS: Patients who were alive and could be traced through the offices of local registrars received an invitation to participate in the follow-up study, consisting of an interview, physical examination, echocardiography, exercise testing and standard 12-lead and 24-h electrocardiography. RESULTS: One hundred nine patients (78% of those eligible for follow-up) participated. The mean interval after operation (+/- SD) was 14.5 +/- 2.6 years. Eighty-four percent of the patients assessed their health as good or very good, and 89% had been free of any medical or surgical intervention since the operation. At physical examination all patients were in good health. Their mean exercise capacity was 100 +/- 17% (range 56% to 141%) of predicted values; 84% of the patients had a normal exercise capacity. Echocardiography demonstrated a small residual ventricular septal defect in seven patients (6%). There were no signs of pulmonary hypertension. No patient had symptomatic arrhythmias. CONCLUSIONS: Long-term results of surgical closure of ventricular septal defect in infancy and childhood are good. Pulmonary hypertension is absent. Personal health assessment is comparable to that of the normal population, as is exercise capacity, even though many patients have anatomic, hemodynamic or electrophysiologic sequelae.

Adolescent↗
PubMed1994

Different pharmacological responses of atrium and ventricle: studies with human cardiac tissue.

It has been recently reported that 5-hydroxytryptamine (5-HT) increases force of contraction in atrial tissue but not in ventricular tissue. In the present study with trabeculae obtained from non-diseased human hearts, we investigated whether this difference in the contractile responses is specific for 5-HT or is also observed for other substances: calcitonin gene-related peptide (CGRP), angiotensin II, adenosine, somatostatin and acetylcholine. CGRP (10(-9) to 10(-7) M) and angiotensin II (10(-9) to 10(-5) M) caused concentration-dependent increases in force of contraction in atrial trabeculae (up to 36 +/- 8% and 42 +/- 8% of the response to 10(-5) M noradrenaline, respectively). Similar to 5-HT, no effects were observed with CGRP and angiotensin II in ventricular trabeculae. Adenosine (10(-8) to 10(-5) M) and somatostatin (10(-8) to 10(-6) M) caused concentration-dependent negative inotropic effects on baseline atrial contractility (-54 +/- 17% and -51 +/- 25%, respectively), but no response was found on baseline ventricular contractility. Adenosine, but not somatostatin, reduced force of contraction after pre-stimulation with 10(-5) M noradrenaline in atrial tissue and, to a lesser extent, in ventricular tissue. Acetylcholine exhibited a biphasic concentration-response curve in the atrial tissue, consisting of an initial negative inotropic response (10(-9) to 10(-7) M, from 120 +/- 41 mg at baseline to 48 +/- 16 mg at 10(-7) M), followed by a positive inotropic response (10(-6) to 10(-3) M, from 48 +/- 16 mg at 10(-7) M to 77 +/- 15 mg).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1994

[Aortic valve replacement using aortic donor valves of human origin].

OBJECTIVE: To evaluate the experiences of aortic valve replacement with cryopreserved aortic allografts in the subcoronary position. DESIGN: Descriptive clinical study. SETTING: Thorax Centre of Rotterdam University Hospital. METHOD: In the period July 1988-March 1993, 68 patients (45 men and 23 women) with a mean age of 45 years underwent 69 operations. One woman was operated twice. Main criteria for aortic valve replacement by an allograft were age and endocarditis. The pathology leading to aortic valve dysfunction had been: endocarditis (38%), congenital lesions (32%), rheumatic lesions (19%), senile degeneration (7%), paravalvular leakage (3%) and an active autoimmune disease (1%). RESULTS: Hospital mortality was 4%. The mean follow-up was 22 months, with a cumulative follow-up of 126 patient years. One patient died of lung cancer during this period. Six patients needed a second operation (9%); 4 of these were among the first 15 patients operated on. One of these reoperations was necessary to treat a recurrent endocarditis. Only one other late valve-related event took place: a transient ischaemic attack 2 years postoperatively. Ninety-one per cent of the patients with an allograft in situ were in NYHA class I at their last outpatient clinic visit. The other patients were in class II. Pre-cordial color Doppler echocardiography showed no or mild aortic regurgitation in 95% of these patients. The remaining 3 patients had moderate aortic regurgitation. CONCLUSION: Aortic valve replacement with an allograft was performed with low hospital mortality. The expected advantages are greatest in young patients and patients with endocarditis; these patients, therefore, should have priority in allograft allocation.

Adolescent↗
PubMed1994

Cytomegalovirus infection and allospecific cytotoxic activity of graft-infiltrating cells after heart transplantation.

We have investigated whether cytomegalovirus (CMV) infection has an effect on donor directed cytotoxicity of graft-infiltrating cells in human heart transplants. Our study group consisted of 89 heart transplant recipients. Thirty-eight (43%) showed signs of CMV infection; in 28 of them, cytolytic activity of biopsy derived cultures could be tested during the infection. Eight patients had a primary and 20 a secondary infection. We found that during CMV infection, both primary and secondary, a significantly higher proportion of the biopsy-derived cultures showed cytotoxicity against donor HLA antigens (chi 2 test; P < 0.01 in comparison with 51 patients without infection). This was most evident in patients with both infection and acute rejection episodes when compared to patients with only one of these complications. This suggests that one process amplifies the other with regard to the up-regulation of alloreactivity within the transplanted heart. In secondary infections, only an increase of donor class I-directed cytotoxicity was found, while in primary infections cytotoxicity against donor class I and II antigens was increased (P < 0.005 vs. secondary infection).

Adolescent↗
PubMed1994

Repair of commissural prolapse by extended leaflet sliding.

Three patients had chronic mitral regurgitation due to commissural chorda rupture with commissural prolapse. Two of them had myxomatous valve disease and 1 had fibroelastic deficiency. Characteristic intraoperative epicardial and transesophageal echocardiographic findings are demonstrated. A technique is proposed that involves creating a new commissure and avoiding annular plication by extended sliding plasty and rotating the posterior mitral leaflet.

Aged↗
PubMed1994

Spark erosion myectomy in hypertrophic obstructive cardiomyopathy.

The design features of the cutting electrode and the electrical characteristics of a monopolar electrosurgical device were specially adapted for performing a septal myectomy in patients with hypertrophic obstructive cardiomyopathy. Both the cutting behavior and electrode design were found to facilitate myectomy.

Adult↗
PubMed1994

Psychosocial functioning of young adults after surgical correction for congenital heart disease in childhood: a follow-up study.

To investigate the long-term psychosocial outcome of congenital heart disease, the emotional, intellectual and social functioning of 288 (young) adult patients was assessed with standardized assessment procedures 9-23 years (mean follow-up interval: 16 years) after surgical correction for congenital heart disease in childhood, and compared with that of reference groups. With respect to emotional functioning, the patients reported significantly fewer feelings of hostility, fewer neurotic complaints and a better self-esteem than reference subjects. Overall, the results concerning social functioning showed favourable outcomes on daily activities (school, employment) and leisure-time activities for (young) adults with congenital heart disease. No significant differences were found between scores of different cardiac diagnostic groups on hostility, neuroticism, self-esteem and leisure-time activities. The possibility whether the 'denial'-mechanism might have contributed to the positive outcomes is discussed.

Activities of Daily Living↗
PubMed1994

Characteristics of graft-infiltrating lymphocytes after human heart transplantation. HLA mismatches and the cellular immune response within the transplanted heart.

The influence of HLA mismatches between donor and recipient on the phenotypes, function, and specificity of T-lymphocyte cultures derived from endomyocardial biopsies was studied in 118 heart transplant recipients. In case of HLA-DR mismatches, the majority of the EMB-derived cultures were dominated by CD4+ T cells while, in patients with HLA-A and -B mismatches but without DR mismatches, CD8+ T cells comprised the predominant T-cell subset. Cytotoxicity against donor antigens was observed in 75% of the cultures. A significantly (p < 0.005) lower proportion of the cultures showed cytotoxicity against HLA-A antigens (36%) when compared with HLA-B (53%) or HLA-DR (49%). An HLA-A2 mismatch elicited a cytotoxic response that was comparable to that found against HLA-B and -DR antigens: 62% of the cultures from HLA-A2 mismatched donor-recipient combinations was reactive against A2. A higher number of A, B, or DR mismatches resulted in a higher number of cytotoxic cultures directed against these antigens. A higher number of HLA-B and -DR mismatches was associated with a lower freedom from rejection. Our data indicate that, despite the use of adequate immunosuppressive therapy, the degree of HLA matching plays a crucial role in the immune response against a transplanted heart, resulting in a significant effect on freedom from rejection.

Acute Disease↗
PubMed1994

Temporary tricuspid valve detachment in closure of congenital ventricular septal defect.

In a consecutive series of 149 patients with congenital ventricular septal defect (VSD), temporary tricuspid valve detachment was applied in 39 (detached group) to facilitate the transatrial approach for closure of the defect. Baseline characteristics showed that, preoperatively, the detached group were younger (1.3 +/- 2.3 vs. 3.5 +/- 4.1 years, P = 0.002), shorter (0.67 +/- 0.20 vs 0.87 +/- 0.34 m, P = 0.001), lighter (6.9 +/- 5.4 vs 13.5 +/- 12.0 kg, P < 0.002), and had a higher mean right atrial pressure (6 +/- 2 vs 4 +/- 3 mm Hg, P < 0.003), mean end-diastolic right ventricular pressure (10 +/- 3 vs 8 +/- 3 mm Hg, P < 0.01) and mean pulmonary vascular resistance (267 +/- 202 vs 170 +/- 131 dyn s cm-5, P < 0.02) on cardiac catheterization. At surgery the aortic cross-clamp time was longer (48 +/- 17 vs 39 +/- 15 min, P = 0.003). Seven patients died (2 detached, 5 not-detached), from causes not related to either tricuspid detachment or VSD closure. Follow-up was complete with a mean duration of 2.0 years (range 0.1-5.5). All 142 survivors were investigated by echocardiography, which showed normal tricuspid valve function in all but 29 patients who had trivial regurgitation (6 detached, 23 not-detached). There was no tricuspid stenosis. In 30 patients (8 detached, 22 not-detached) a trivial residual VSD could be detected. One reoperation (not-detached) was performed 12.5 months after the initial surgery for recurrent VSD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Long-term results of the gamma-irradiation-preserved homograft monocusp for transannular reconstruction of the right-ventricular outflow tract in tetralogy of Fallot.

The long-term results of a consecutive series of transannular gamma-irradiated homograft monocusp patches in tetralogy of Fallot were studied. Seven survivors out of 8 patients are doing clinically well after a mean of 22.4 years of follow-up, 5 of them being in New York Heart Association class I and 2 in class II. In one patient the completely calcified gamma-irradiated homograft monocusp patch was replaced 15 years after intracardiac repair. Echocardiographic investigation at the end of follow-up of the remaining 6 patients with a gamma-irradiated homograft monocusp patch in situ showed mild pulmonary regurgitation in 1, moderate regurgitation in 3, and severe regurgitation in 2. Residual pulmonary stenosis was present in 4 patients (gradients ranging from 10 to 40 mmHg). Right-ventricular dilatation was present in all patients. In the long-term the gamma-irradiated transannular homograft monocusp patch behaves like a simple transannular patch.

Adolescent↗
PubMed1994

Cytokine gene expression profiles in human endomyocardial biopsy (EMB) derived lymphocyte cultures and in EMB tissue.

The reverse transcriptase polymerase chain reaction (RT-PCR) technique was used to analyse cytokine gene expression in relation to acute cardiac rejection. Expression of interleukins, IL-2, IL-4, IL-6 and IL-10 mRNA was studied in sequential endomyocardial biopsies (EMB) and in graft-infiltrating lymphocyte (GIL) cultures propagated from EMB taken after heart transplantation. The cytokine gene expression of GIL propagated from EMB taken during an episode of rejection and of immunological quiescence was comparable. In contrast, posttransplant EMB showed selective IL-2 gene expression when rejection was diagnosed. IL-4 mRNA was absent in pretransplant EMB but present in posttransplant EMB taken during periods of rejection and of immunological quiescence. Both IL-6 and IL-10 transcripts were found in pre- and posttransplant EMB. These findings confirmed that IL-2 is specifically involved in cardiac rejection, while IL-4 may play a role in immune responses leading to graft rejection or graft tolerance.

Biopsy↗
PubMed1994

Time course of the decline in renal function in cyclosporine-treated heart transplant recipients.

The renal side-effects are a major limitation of the use of cyclosporine A (CsA) following heart transplantation. In an effort to define the time course of the decline in renal function and to identify a group of patients especially prone to the nephrotoxic effects of CsA, we studied 187 orthotopic heart transplant recipients who had a follow-up of at least 1 month. All patients received oral CsA in a starting dose of 8 mg/kg and low-dose steroids. Renal function decreased steadily after transplantation. Serum creatinine was > 150 mumol/l in 52% of the patients after 2 years. After 4 years serum creatinine was > 250 mumol/l in 13% of the patients. No relation could be found between the decline in renal function (as defined by the slope of serum creatinine-1 versus time) and age, sex, creatinine levels before transplantation, blood pressure, CsA blood levels, the number of rejections or the use of calcium channel blocking drugs. We conclude that, despite reduction of CsA dosage, progressive renal insufficiency can be observed in an increasing percentage of heart transplant recipients. We were not able to identify patients with a poor renal prognosis in an early phase after transplantation.

Adult↗
PubMed1994

Low-dose aspirin inhibits platelet-induced contraction of the human isolated coronary artery. A role for additional 5-hydroxytryptamine receptor antagonism against coronary vasospasm?

BACKGROUND: The beneficial effect of low-dose aspirin in the prevention of coronary vasospasm is well documented. In this study, we investigated the contractile effect of human washed platelets on the human isolated coronary artery. We concentrated on the effect of low-dose aspirin (40 mg/d) taken by the platelet donor and on the efficacy of thromboxane A2 (TXA2) and 5-hydroxytryptamine (5-HT) receptor antagonists. METHODS AND RESULTS: Human coronary artery segments were suspended in an organ bath set-up for isometric tension measurement. Platelets (10(9) to 3 x 10(10)/L) elicited concentration-dependent contractile responses of the coronary artery segments, reaching 28.4 +/- 7.1% of contractions induced by 100 mmol/L K+. The contractile response tended to be decreased in vessel segments with histological signs of early atherosclerosis. Contraction was significantly attenuated after pretreatment of the vessel segments with ketanserin (5-HT2 receptor antagonist, 1 mumol/L) or SQ30741 (TXA2 receptor antagonist, 0.01 mumol/L), reaching 8.8 +/- 2.3% and 3.2 +/- 2.2% of contraction to 100 mmol/L K+, respectively. Platelets obtained from the same platelet donors after they had taken aspirin (40 mg/d for 7 to 13 days) caused significantly lower contractile responses (7.6 +/- 2.7% of 100 mmol/L K+) associated with an almost selective inhibition of the synthesis of thromboxane measured in the organ bath solution (untreated platelets, 2.19 +/- 0.43 nmol/L; aspirin-treated platelets, 0.66 +/- 0.05 nmol/L). The amount of 5-HT secreted in the organ bath remained unaltered (65.17 +/- 9.94 and 64.03 +/- 8.98 nmol/L, respectively). This explains why ketanserin significantly attenuated the residual contractile responses caused by platelets obtained from aspirin-treated subjects, whereas SQ30741 caused minor, nonsignificant additional attenuation. CONCLUSIONS: The results of the present study therefore suggest that additional antagonism of the contractile 5-HT receptors in the coronary artery may increase the efficacy of low-dose aspirin in vivo.

Adolescent↗
PubMed1994

Abnormal diurnal variation of blood pressure, cardiac output, and vascular resistance in cardiac transplant recipients.

BACKGROUND: An attenuated or absent nocturnal decline in blood pressure has repeatedly been documented in cardiac transplant recipients. The present study was aimed at investigating the hemodynamic mechanism underlying this abnormality. METHODS AND RESULTS: In 23 cardiac transplant recipients (11 to 36 months after transplantation) and in 23 control subjects matched for age and 24-hour mean arterial pressure, invasive 24-hour ambulatory blood pressure was measured by means of the Oxford technique. Beat-to-beat relative values of stroke volume were determined by means of a pulse-contour method, and relative changes of cardiac output (stroke volume x heart rate) and total peripheral vascular resistance (blood pressure/cardiac output) over the 24-hour period were calculated. The nocturnal decline in blood pressure was 20 +/- 8% (mean +/- SD) in control subjects but only 5 +/- 9% (P < .001) in cardiac transplant recipients. In control subjects, the nocturnal decline in blood pressure was associated with a nocturnal fall in cardiac output of 24 +/- 13%, whereas vascular resistance compared with daytime value did not change. The small nocturnal decline in blood pressure in cardiac transplant recipients was associated with an attenuated nocturnal fall in cardiac output of 14 +/- 12% (P < .05 versus control subjects). In addition, vascular resistance compared with daytime value was increased by 9 +/- 9% (P < .05) during the night. Both in cardiac transplant recipients and in control subjects, the nocturnal changes in blood pressure were correlated with the nocturnal changes in cardiac output but not with the nocturnal changes in total peripheral vascular resistance. CONCLUSIONS: This study confirms the attenuated nocturnal fall in blood pressure in cardiac transplant recipients. Hemodynamically, this attenuated blood pressure decline is characterized by a reduced nocturnal fall in cardiac output, and it is associated with a nocturnal increase in vascular resistance.

Adolescent↗
PubMed1994

Anatomy of the proximal coronary arteries as a risk factor in primary repair of common arterial trunk.

The objective of this study was to investigate whether the proximal coronary arterial anatomy is a risk factor in surgical treatment of common arterial trunk, with special focus on the value of preoperative angiocardiography. A retrospective analysis was performed of all 22 patients who underwent primary surgical repair of the common arterial trunk, with a mean follow-up of 5.1 years. In 18 patients preoperative angiocardiography was performed. Anatomical features (angiocardiographical, surgical as well as post-mortem) of the proximal coronary arteries were investigated. With standard biplane angiocardiography single and dual coronary arterial systems could adequately be distinguished. However, the position of the coronary orifices in relation to the sinus of Valsalva could not adequately be identified. Three patients had coronary abnormalities without surgical consequences. In 2 cases the surgical approach had to be modified due to the coronary anatomy. Early mortality was 23% (5/22) and was correlated with worse functional class (p < 0.05) and earlier date of operation (p < 0.05). Late mortality was 5% (1/22). Five patients were reoperated, without mortality. Fourteen surviving patients are in functional class I, and 2 in class II. A further improvement of the surgical therapy of common arterial trunk might be provided by adequate appreciation of the proximal coronary arterial anatomy at surgery.

Abnormalities, Multiple↗