Biomedical subjects
Publications and source records attributed to Paul H Schoof.
Isolated congenital tricuspid valve regurgitation in a neonate was associated with heart failure and functional pulmonary atresia. Surgical repair of the ruptured chordae with the use of polytetrafluoroethylene artificial tendinous cords restored normal hemodynamics.
BACKGROUND: This study evaluated the diameters and distensibility of the aortic root as well as the degree of aortic regurgitation (AR) and its effect on left ventricular (LV) function in patients 8.2 +/- 3.1 years after they underwent the Ross procedure, with a comparison of these parameters between patients and matched healthy subjects. METHODS: Eighteen Ross procedure patients (16 male patients, age [mean +/- SD] 19.2 +/- 3.8 years) and 18 matched healthy subjects (16 male patients, age [mean +/- SD] 19.7 +/- 4.2 years) underwent magnetic resonance imaging. Measurements for diameters (at 4 levels) and the distensibility of the aortic root were performed using a steady-state free precession sequence. Aortic flow was assessed with a velocity-encoded phase-contrast sequence. Left ventricular systolic function was assessed with a gradient-echo sequence in the short-axis plane. Comparison of parameters was performed using the Mann-Whitney U test. Correlations between diameters, distensibility, AR fraction, and LV systolic function were expressed with Spearman rank correlation coefficients. Linear regression analysis was used to identify predictors of LV systolic dysfunction. RESULTS: Aortic root diameters were increased in Ross procedure patients as compared with healthy subjects (mean difference 6.3-11.6 mm, P < or = .02 at all 4 levels). Distensibility of the aortic root was lower in patients (1.9 +/- 1.1 vs 7.8 +/- 3.3 mm Hg(-1), P < .01). An AR fraction > 5% was present in 14 of the 18 patients (mean AR fraction 8% +/- 5% vs 1% +/- 1%, P < .01). Left ventricular ejection fraction was lower in patients (50% +/- 6% vs 57% +/- 6%, P < .01). Dilatation, decreased distensibility, and AR fraction were correlated with impaired LV systolic function (P < .05 for all). The AR fraction predicted impaired LV systolic function (P < .01). CONCLUSIONS: Magnetic resonance imaging shows dilatation and decreased distensibility of the aortic root, AR, and consequent impaired LV systolic function in patients after the Ross procedure.
BACKGROUND: Contact of blood with the artificial surfaces of the cardiopulmonary bypass (CPB) system is considered to be a main cause of complement activation. Improving the biocompatibility of the system by reduction of contact activation of blood elements and thereby producing less inflammatory response is evidently desired, especially for neonates and infants who are more susceptible to the deleterious effects of CPB. A phosphorylcholine coating, Phisio, is designed to mimic the natural interfaces of blood. The aim of this study is to compare the influence of a phosphorylcholine-coated CPB system versus an uncoated CPB system on complement activation and clinical outcomes. METHODS: In this prospective, randomized, blind, one-center study, 28 neonates and infants with a bodyweight between 3 and 6 kg who were undergoing cardiopulmonary bypass were divided in two groups, the phosphorylcholine group and the control group. Thirteen patients were assigned to the phosphorylcholine group and 15 patients to the control group. Patients with Down syndrome, prematurity, cyanosis, or reoperation were excluded. Complement factor C3b/c, human neutrophil elastase (HNE), interleukin-6, and C-reactive protein were measured before, during, and after CPB. Duration of intensive care stay, ventilation time, highest body temperature, and inotropic medication were the clinical variables. RESULTS: No significant differences were found between the groups for complement factor C3b/c, HNE, interleukin-6, or C-reactive protein during and after CPB. No clinical differences were observed between the groups. CONCLUSIONS: Phosphorylcholine coating does not attenuate the complement activation during CPB in neonates and infants.
OBJECTIVE: We sought to determine the histologic features of pulmonary autografts explanted after the Ross operation. METHODS: Histologic sections of 30 explanted autografts and 8 normal heart valves were compared and semiquantitatively scored by a blinded cardiovascular pathologist. RESULTS: Pulmonary autografts (n = 30) were explanted on average 6.1 +/- 0.6 years (median, 6.6 years; range, 0.1-11.7 years) after the Ross operation (n = 28) or removed at autopsy (n = 2). Twelve (43%) of the patients undergoing reoperation had no or negligible autograft insufficiency on early transthoracic echocardiography, 12 (43%) had grade 1 autograft insufficiency, and 4 (14%) had grade 1-2 autograft insufficiency. Valve regurgitation with root dilatation was the most common indication for reoperation after root replacement (n = 26 [93%]) and regurgitation after subcoronary implanted autografts (n = 2 [7%]). Microscopy of the autograft explants revealed normal laminar architecture and cellularity. Wall specimens were characterized by reduced and fragmented elastin and increased collagen levels (fibrosis). Medial elastin changes were associated with the presence of hypertrophic smooth muscle cells. Fibrosis was most severe in the adventitia. Intimal thickening was a common finding. Valve explants showed significant thickening caused by fibrocellular tissue on the ventricular surface and marked thickening of the free margin. An autopsy explant with normal function before death showed similar features. CONCLUSIONS: Pulmonary autograft explants showed severe aneurysmal degeneration of the wall, which was characterized by intimal thickening, medial elastin fragmentation, and adventitial fibrosis. Valve leaflets were thickened. The presence of these features in a nonfailing explant suggests these changes represent a common mode of remodeling.
OBJECTIVE: To analyse the results of the mid-term clinical and echocardiographic follow-up of the pediatric Ross operation. METHODS: Echo-Doppler follow-up of 53 consecutive pediatric Ross procedures performed between 1994 and 2003. Median age was 9.7 years at time of operation (2 weeks-17.7 years). Six patients were younger than 3 months. Median age at follow-up was 15.6 years. Aortic valve/left ventricular outflow tract (LVOT) anomalies were congenital in 49 (92%). Seventy percent had previous surgery or balloon valvuloplasty. Root replacement was used in all. Thirteen patients (25%) had LVOT enlargement. Mean cross-clamp time was 113 (69-189) minutes. RESULTS: Early mortality occurred in 3 patients after emergency surgery following balloon failure (n=1) and extended Ross following interrupted arch/VSD repair (n=2). Late mortality was due to LV fibroelastosis in 2 patients and complicated pulmonary artery stenting in another. RVOT reoperations were required because of late homograft obstruction in 2 patients and because of pulmonary artery stenosis in another. Five patients (9.4%) were reoperated for pulmonary autograft dilatation (n=3) and for leaflet fibrosis or perforation (n=2). Autografts were repaired in two patients, while a mechanical valve was inserted in 3 cases. At 9 years the actuarial survival and event free survival were 89 and 74%, respectively. At last follow-up 90% of autograft diameters indexed to body surface area was above the 90th percentile of normal aortic root diameters. LVOT and RVOT gradients were low and autograft insufficiency was trivial to mild in 84% and mild to moderate in 16%. Autograft stenosis was not noticed. CONCLUSIONS: The pediatric Ross procedure remains an important tool but autograft dilatation also occurs in the pediatric population. The significance of this finding has yet to be determined.
We report the usefulness of a median sternotomy approach for the surgical treatment of residual aortic gradients or recoarctation and aortic aneurysms. This series confirms that excellent surgical results can be obtained in this technically challenging group of patients needing postcoarctation repair.
PURPOSE: To assess the time course of right ventricular (RV) function improvement after pulmonary valve replacement (PVR) in patients 25.2 years +/- 7.0 after repair of tetralogy of Fallot. MATERIALS AND METHODS: The medical ethics committee approved this study, and informed consent was obtained. Cardiac magnetic resonance (MR) imaging was performed before, 7 months after, and 19 months after PVR in 25 consecutive patients with tetralogy of Fallot with a 1.5-T MR imager. RV function was assessed with gradient-echo sequences in the short-axis plane. Pulmonary flow was assessed with a velocity-encoded phase-contrast sequence. Paired t test was used to evaluate follow-up data. Independent samples t test was used to assess differences based on the presence of recurrent pulmonary regurgitation (PR). RESULTS: Mean indexed RV end-diastolic volume decreased from 166.9 mL/m(2) +/- 41.3 before PVR to 113.5 mL/m(2)+/- 35.7 (P < .001) at 7-month follow-up and 111.7 mL/m(2)+/- 41.1 (P = .46) at 19-month follow-up. The RV ejection fraction was corrected for PR and improved from 25.0% +/- 7.7 before surgery to 44.1% +/- 11.9 (P < .001) and 45.2% +/- 11.1 (P = .39), at 7- and 19-month follow-up, respectively. Recurrent PR after PVR was found in 11 patients; 14 patients did not have recurrent PR. Total reduction of indexed RV end-diastolic volume at 19 months follow-up was more prominent in patients who did not have recurrent PR than in patients who did have recurrent PR (P < .05). Furthermore, improvement of RV ejection fraction corrected for regurgitation was more marked in patients who did not have recurrent PR than in patients who did have recurrent PR (P < .05). CONCLUSION: In patients with tetralogy of Fallot, RV function improves rapidly after PVR and is sustained at 19-month follow-up in most patients; however, recurrence of PR after PVR appears to reduce recovery of RV systolic function.
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OBJECTIVE: Transposition of the great arteries is currently treated by performing the arterial switch operation. Dilatation of the neoaortic root is a late complication with unknown cause. Samples of patients with untreated transposition of the great arteries and patients with normally related great arteries were compared to investigate a possible role for vascular remodeling in the dilatation process. METHODS: Aortic and pulmonary artery vessel wall and sinus samples were taken from 20 untreated human heart specimens with transposition of the great arteries and 9 age-matched, normal, postmortem human heart specimens, divided into 2 groups according to age. Routine histology and immunohistochemical staining for smooth muscle cell differentiation markers alpha-smooth muscle actin, SM22, and calponin were performed. RESULTS: This study revealed structural differences between the normal aorta and pulmonary artery in the early group, which became more pronounced in the late group. In the early stage in transposition of the great arteries, no marked differences were seen between the aorta and pulmonary artery. With increasing age, however, there was a pronounced down-regulation of all smooth muscle cell markers in the pulmonary artery. CONCLUSIONS: There is a structural difference between the normal neonatal aorta and pulmonary artery. The great arteries in transposition of the great arteries differ from each other and from normal vessels, indicating a structural vascular difference in transposition of the great arteries. In the pulmonary artery and sinus of untreated transposition of the great arteries, there is a dedifferentiation of smooth muscle cells with increasing age that we could not correlate to altered flow. This structural abnormality might provide an explanation for the neoaortic root dilatation that has been reported as a late complication of the arterial switch operation.
OBJECTIVE: Banding of the pulmonary artery might be required to prevent pulmonary vascular damage in patients with increased pulmonary artery flow and to retrain the left ventricle in preparation for an arterial switch operation in patients with congenitally corrected transposition of the great arteries. Readjustment of the pulmonary artery band might be required in the postoperative period. In this study we aimed to test the feasibility of a novel device for bidirectionally adjustable pulmonary artery constriction. METHODS: A hydraulic main pulmonary artery occluder was implanted in lambs and gradually inflated to create right ventricular pressure overload at a systemic (aortic) level. During the following period (up to 12 weeks), this pressure overload was monitored by measuring aortic and right ventricular pressures by means of implanted subcutaneous reservoirs. If required to maintain the right ventricular pressure overload at a systemic level in the growing animals, the occluder was deflated through a third subcutaneous reservoir. RESULTS: After the banding period (average of 64 +/- 8 days), the main pulmonary artery cuff could still be adjusted, and the animals showed no clinical signs of heart failure. Histologic analysis of the pulmonary artery showed extensive fibrosis, a giant cell response around the device, and small areas of tissue necrosis; complete transmural necrosis was not detected. CONCLUSIONS: This device allows adjustment of the pulmonary artery cuff in a precise manner over a prolonged period of time without surgical reintervention. Potentially, the device might have applications for clinical use in children with congenital heart disease.
OBJECTIVE: Right ventricular pressure overload occurs in several types of (congenital) heart disease, as well as in pulmonary disease. Clinical outcome in some of these patient groups might in part be related to left ventricular loading conditions. The effects of left ventricular unloading on the function of the hypertrophic right ventricle have not been studied. We aimed to study the effects of left ventricular unloading on right ventricular hemodynamics and contractility in an animal model of chronic right ventricular pressure overload. METHODS: In lambs the pulmonary artery was chronically banded to increase right ventricular pressure to systemic levels. After 8 weeks, right ventricular contractility and hemodynamic function were assessed in these lambs, as well as in age-matched control animals, by using a combined pressure-conductance catheter in the right ventricle during baseline conditions and during complete bypass of the left ventricle. RESULTS: In both groups acute left ventricular unloading significantly decreased left ventricular pressure to low levels while aortic pressure was maintained. In the right ventricle of the control group, both end-systolic and end-diastolic volumes increased with left ventricular unloading (P <.01) while end-systolic pressure was maintained. Cardiac output was unchanged despite decreased right ventricular contractility. In the banding group acute left ventricular unloading also decreased right ventricular contractility but increased cardiac output. During acute left ventricular unloading, diastolic stiffness was unchanged in the control group, whereas it was significantly decreased in the banding group. CONCLUSIONS: Both in normal hearts and in hearts subject to chronic right ventricular pressure overload, acute left ventricular unloading decreases right ventricular contractility. Although no effects on cardiac output are encountered in normal hearts during left ventricular bypass, cardiac output is improved in right ventricular pressure-overloaded hearts, most likely related to improved right ventricular diastolic compliance.
BACKGROUND: Pulmonary regurgitation (PR) late after total correction for tetralogy of Fallot may lead to progressive right ventricular (RV) dilatation and an increased incidence of severe arrhythmias and sudden death. Timing of pulmonary valve replacement (PVR) is subject to discussion, because the effect of PVR on RV function in adults is unclear. In this study, MRI was used to assess the effect of PVR on RV function and PR. Clinical improvement was established by means of the NYHA classification. METHODS AND RESULTS: Twenty-six adult patients were included. Cardiac MRI was performed at a median of 5.1+/-3.4 months before and 7.4+/- 2.4 months after PVR. Mean preoperative PR was 46+/-10% (range, 25% to 64%). After PVR, 20 of 26 patients (77%) showed no residual PR, 5 patients showed mild residual PR, and 1 patient showed moderate PR. RV end-diastolic volume (RV-EDV) decreased from 305+/-87 to 210+/-62 mL (P<0.001), and RV end-systolic volume (RV-ESV) decreased from 181+/-67 to 121+/-58 mL (P<0.001). No significant change was found in RV-EF (42% versus 42%). However, RVEF corrected for regurgitations and shunting increased from 25.2+/-8.0% to 43.3+/-13.7% (P<0.001). Mean validity class improved from 2.0 to 1.3 (P<0.001). CONCLUSIONS: In adult patients with PR and RV dilatation, late after total correction of tetralogy of Fallot, MRI measurements show remarkable hemodynamic improvement of RV function after PVR and improvement of validity. We therefore advocate a less restrictive management concerning PVR in these patients.
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