"Fontan Conduit Stent-Angioplasty and Progression of Fontan-Associated Liver Disease".

Patients with Fontan circulation insidiously develop congestive hepatopathy related to chronically reduced cardiac output and central venous hypertension, also known as Fontan-associated liver disease (FALD). Fontan pathway obstruction is increasingly detected and may accelerate FALD. The impact of conduit stent angioplasty on FALD is unknown. Retrospective, single-center review of patients with Fontan circulation who underwent conduit stent angioplasty at cardiac catheterization over 5-year period. Demographics and cardiac histories were reviewed. Labs, liver ultrasound elastography, echocardiogram, hemodynamic and angiographic data at catheterization were recorded pre- and post-stent angioplasty. Primary outcome was change in hepatic function via MELD-XI scores and liver stiffness (kPa), with secondary outcomes of ventricular function, BNP, and repeat catheterization hemodynamics. 33 patients underwent Fontan conduit stent angioplasty, 19.3 ± 7.0 years from Fontan operation. Original conduit diameter was 19.1 ± 1.9 mm. Prior to angioplasty, conduit size was reduced to a cross-sectional area 132 (91, 173) mm2 and increased to 314 (255, 363) mm2 post-stent. Subjects' baseline median MELD-XI of 11 (9, 12) increased to 12 (9, 13) at 19 ± 15.5 months post-angioplasty (n = 22, p = 0.053). There was no significant change in liver stiffness at 12.1 ± 8.9 months post-angioplasty (n = 15, p = 0.13). Median total bilirubin significantly increased (1.4 [0.9, 1.8]), from baseline 1.1 [0.7, 1.5], p = 0.04), as did median BNP (41 [0, 148] from baseline 34 [15, 79]; p = 0.02). There were no significant changes in ventricular function or repeat invasive hemodynamics (n = 8 subjects). Mid-term follow-up of Fontan subjects post-conduit stent angioplasty did not show improvements in non-invasive markers of FALD.

Utilization of an Abiomed Impella Device as a Rescue Therapy for Acute Ventricular Failure in a Fontan Patient.

Progressive ventricular dysfunction is not uncommon in patients with univentricular hearts as they age. In the acute setting vasoactive support can be employed, but is not always sufficient and patients occasionally require mechanical support. We report the successful implantation and subsequent challenges of a percutaneous Abiomed Impella ventricular assist device as a rescue therapy for a 15-year old-patient with Fontan circulation and severe ventricular dysfunction after cardiac arrest.

Longitudinal measures of deformation are associated with a composite measure of contractility derived from pressure-volume loop analysis in children.

Aims: The relationship between echocardiographic measures of left ventricular (LV) systolic function and reference-standard measures have not been assessed in children. The objective of this study was to assess the validity of echocardiographic indices of LV systolic function via direct comparison to a novel composite measure of contractility derived from pressure-volume loop (PVL) analysis. Methods and results: Children with normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. A composite invasive composite contractility index (ICCI) was developed using data reduction strategies to combine four measures of contractility derived from PVL analysis. Echocardiograms were performed immediately after PVL analysis under the same anesthetic conditions. Conventional and speckle-tracking echocardiographic measures of systolic function were measured. Of 24 patients, 18 patients were heart transplant recipients, 6 patients had a small patent ductus arteriosus or small coronary fistula. Mean age was 9.1 ± 5.6 years. Upon multivariable regression, longitudinal strain was associated with ICCI (ß = -0.54, P = 0.02) while controlling for indices of preload, afterload, heart rate, and LV mass under baseline conditions. Ejection fraction and shortening fraction were associated with LV mass and load indices, but not contractility. Conclusion: Speckle-tracking derived longitudinal strain is associated ICCI in children with normal loading conditions. Longitudinal measures of deformation appear to accurately assess LV contractility in children.

Echocardiographic Detection of Increased Ventricular Diastolic Stiffness in Pediatric Heart Transplant Recipients: A Pilot Study.

BACKGROUND: Pediatric heart transplant recipients are at risk for increased left ventricular (LV) diastolic stiffness. However, the noninvasive evaluation of LV stiffness has remained elusive in this population. The objective of this study was to compare novel echocardiographic measures of LV diastolic stiffness versus gold-standard measures derived from pressure-volume loop (PVL) analysis in pediatric heart transplant recipients. METHODS: Patients undergoing left heart catheterization were prospectively enrolled. PVLs were obtained via conductance. The end-diastolic pressure-volume relationship was obtained via balloon occlusion. The stiffness constant, ß, was calculated. Echocardiographic measures of diastolic function were derived from spectral and tissue Doppler and two-dimensional speckle-tracking. Ventricular volumes were measured using three-dimensional echocardiography. The novel echocardiographic estimates of ventricular stiffness included E:e'/end-diastolic volume (EDV) and E:early diastolic strain rate/EDV. RESULTS: Of 24 children, 18 were heart transplant recipients. Six control patients had hemodynamically insignificant patent ductus arteriosus or coronary fistula. The mean age was 9.1 ± 5.6 years. Median end-diastolic pressure was 9 mm Hg (interquartile range, 8-13 mm Hg). Lateral E:e'/EDV (r = 0.59, P < .01), septal E:e'/EDV (r = 0.57, P < .01), and (E:circumferential early diastolic strain rate)/EDV (r = 0.54, P < .01) correlated with ß. Lateral E:e'/EDV displayed a C statistic of 0.93 in detecting patients with abnormal LV stiffness (ß > 0.015 mL-1). A lateral E:e'/EDV of >0.15 mL-1 had 89% sensitivity and 93% specificity in detecting an abnormal ß. CONCLUSIONS: Echocardiographic estimates of ventricular stiffness may be accurate compared with the gold standard in pediatric heart transplant recipients. The clinical usefulness of these noninvasive measures in assessing LV stiffness merits further study in children.

Ductus Arteriosus Banding to Facilitate Stenting During the Hybrid Stage I Procedure.

Neonates with hypoplastic left heart syndrome and high-risk factors for an open Norwood procedure may benefit from a hybrid stage I procedure. The presence of a giant patent ductus arteriosus prevents safe deployment of the ductus arteriosus stent. We describe a new technique that involves banding the patent ductus arteriosus, therefore allowing stent implantation during hybrid stage I palliation.

Validation of Noninvasive Measures of Left Ventricular Mechanics in Children: A Simultaneous Echocardiographic and Conductance Catheterization Study.

BACKGROUND: The accuracy of echocardiography in evaluating left ventricular contractility has not been validated in children. The objective of this study was to compare echocardiographic measures of contractility with those derived from pressure-volume loop (PVL) analysis in children. METHODS: Patients with relatively normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. The gold-standard measure of contractility, end-systolic elastance (Ees), was obtained via balloon occlusion of one or both vena cavae. Echocardiograms were performed immediately after PVL analysis under the same anesthetic conditions. Single-beat estimations of echocardiographic Ees were calculated using four different methods. These estimates were calculated using a combination of noninvasive blood pressure readings, ventricular volumes derived from three-dimensional echocardiography, and Doppler time intervals. RESULTS: Of 24 patients, 18 patients were heart transplant recipients, and six patients had small patent ductus arteriosus or small coronary fistulae. The mean age was 9.1 ± 5.6 years. The average invasive Ees was 3.04 ± 1.65 mm Hg/mL. Invasive Ees correlated best with echocardiographic Ees by the method of Tanoue (r = 0.85, P < .01), with a mean difference of -0.07 mm Hg/mL (95% limits of agreement, -2.0 to 1.4 mm Hg/mL). CONCLUSIONS: Echocardiographic estimates of Ees correlate well with gold-standard measures obtained via conductance catheters in children with relatively normal loading conditions. The use of these noninvasive measures in accurately assessing left ventricular contractility appears promising and merits further study in children.

Impact of pre-stage II hemodynamics and pulmonary artery anatomy on 12-month outcomes in the Pediatric Heart Network Single Ventricle Reconstruction trial.

OBJECTIVE: To compare the interstage cardiac catheterization hemodynamic and angiographic findings between shunt types for the Pediatric Heart Network Single Ventricle Reconstruction trial. The trial, which randomized subjects to a modified Blalock-Taussig shunt (MBTS) or right ventricle-to-pulmonary artery shunt (RVPAS) for the Norwood procedure, demonstrated the RVPAS was associated with a smaller pulmonary artery diameter but superior 12-month transplant-free survival. METHODS: We analyzed the pre-stage II catheterization data for the trial subjects. The hemodynamic variables and shunt and pulmonary angiographic data were compared between shunt types; their association with 12-month transplant-free survival was also evaluated. RESULTS: Of 549 randomized subjects, 389 underwent pre-stage II catheterization. A smaller size, lower aortic and superior vena cava saturation, and higher ventricular end-diastolic pressure were associated with worse 12-month transplant-free survival. The MBTS group had a lower coronary perfusion pressure (27 vs 32 mm Hg; P<.001) and greater pulmonary blood flow/systemic blood flow ratio (1.1 vs 1.0, P=.009). A greater pulmonary blood flow/systemic blood flow ratio increased the risk of death or transplantation only in the RVPAS group (P=.01). The MBTS group had fewer shunt (14% vs 28%, P=.004) and severe left pulmonary artery (0.7% vs 9.2%, P=.003) stenoses, larger mid-main branch pulmonary artery diameters, and greater Nakata indexes (164 vs 134, P<.001). CONCLUSIONS: Compared with the RVPAS subjects, the MBTS subjects had more hemodynamic abnormalities related to shunt physiology, and the RVPAS subjects had more shunt or pulmonary obstruction of a severe degree and inferior pulmonary artery growth at pre-stage II catheterization. A lower body surface area, greater ventricular end-diastolic pressure, and lower superior vena cava saturation were associated with worse 12-month transplant-free survival.

Comparison of Norwood shunt types: do the outcomes differ 6 years later?

BACKGROUND: A modification to the Norwood procedure involving a right ventricle-to-pulmonary artery (RV-PA) shunt may improve early postoperative outcomes. Concerns remain about the effect of the right ventriculotomy required with this shunt on long-term ventricular function. METHODS: Between January 2000 and April 2005, 76 patients underwent the Norwood procedure, 35 with a modified Blalock-Taussig shunt (mBTS) and 41 with a RV-PA shunt. Patients were monitored until death or September 1, 2009, with an average follow-up of 6.8 years. Cardiac catheterization, echocardiograms, perioperative Fontan courses, and need for cardiac transplantation were compared between groups. RESULTS: Cumulative survival was 63% (22 of 35) in the mBTS group vs 78% (32 of 41) in the RV-PA group (p = 0.14). Pre-Fontan echocardiography revealed poorer ventricular function in RV-PA patients (p = 0.03). Cardiac transplantation was required in 6 of 32 (19%) patients with a prior RV-PA shunt vs 1 of 23 (4%) in the mBTS group (p = 0.06). This results in an almost identical cumulative transplant-free survival between groups; 60% (21 of 35) in the mBTS group and 63% (26 of 41) in the RV-PA group (p = 0.95). CONCLUSIONS: Neither shunt offers a clear survival advantage through an average follow-up of 6.8 years. The RV-PA shunt results in impaired late ventricular function that may result in an increased need for cardiac transplantation.

Effect of preoperative use of propranolol on postoperative outcome in patients with tetralogy of Fallot.

The aim of this study was to determine if preoperative propranolol therapy has a deleterious effect on postoperative variables in patients with tetralogy of Fallot. Data from 97 patients who underwent complete repair of tetralogy of Fallot were reviewed. The patients were divided into 2 groups: those receiving preoperative propranolol therapy (n = 32) and those not receiving therapy (n = 65). Preoperative and intraoperative variables did not differ between groups. There were no differences in postoperative inotrope scores on arrival to the intensive care unit and through the first 12 hours postoperatively. There was a trend toward increased inotrope scores at 24 hours (median 8 vs 5, p = 0.05) and 48 hours (median 8 vs 3, p = 0.05) postoperatively in the patients treated with propranolol. Temporary pacing in the early postoperative period occurred more often in the propranolol group (16% vs 3%, p = 0.04). There was no difference between groups in length of mechanical ventilation, intensive care unit stay, or total hospital postoperative stay. In conclusion, propranolol therapy can be used in patients with tetralogy of Fallot until the time of surgery, without important effects on their postoperative courses. Any blunting of inotropic or chronotropic activity in propranolol-treated patients appears to be easily overcome with increased inotropic medications or temporary pacing, without increased morbidity or mortality.

Does a ventriculotomy have deleterious effects following palliation in the Norwood procedure using a shunt placed from the right ventricle to the pulmonary arteries?

INTRODUCTION: A recent modification to the Norwood procedure involving a shunt placed directly from the right ventricle to the pulmonary arteries may improve postoperative haemodynamics. Concerns remain, however, about the potential problems produced by the required ventriculotomy. METHODS: We compared 76 patients with hypoplastic left heart syndrome who underwent the Norwood procedure, 35 receiving a modified Blalock-Taussig shunt and the remaining 41 a shunt placed directly from the right ventricle to the pulmonary arteries. We reviewed their subsequent progress through the second stage of palliation. A single observer graded right ventricular function, and the severity of tricuspid regurgitation, based on blinded review of the most recent echocardiograms prior to the second stage of palliation. RESULTS: At the time of catheterization prior to the second stage, patients with a shunt placed from the right ventricle to the pulmonary arteries, rather than a modified Blalock-Taussig shunt, had higher arterial diastolic blood pressure, at 44 versus 40 millimetres of mercury, p equal to 0.02, lower ventricular end diastolic pressures, at 8 versus 11 millimetres of mercury, p equal to 0.0002, and larger pulmonary arteries as judged using the Nakata index, at 270 versus 188 millimetres squared per metres squared, p equal to 0.009. There was no difference in qualitative ventricular systolic function or tricuspid regurgitation between groups. No differences were found between groups during the hospitalization following the second stage of palliation. A trend towards improved survival to the second stage was seen following the construction of a shunt from the right ventricle to the pulmonary arteries. CONCLUSIONS: Construction of a shunt from the right ventricle to the pulmonary arteries is associated with lower right ventricular end diastolic pressures, larger pulmonary arterial size, and higher systemic arterial diastolic pressures. No apparent deleterious effects of the right ventriculotomy were observed in terms of qualitative ventricular systolic function or tricuspid regurgitation.

Right ventricular outflow tract stent as a bridge to surgery in a premature infant with tetralogy of Fallot.

Despite dramatic progress in neonatal cardiac surgery, prematurity and low birth weight remain risk factors for poor outcome. Attempts to delay intervention with supportive therapy have been shown to increase morbidity and mortality. We present a case of an 840 gram, 28-week gestation newborn with tetralogy of Fallot, in whom palliation was achieved with a right ventricular outflow tract stent. This management allowed subsequent successful complete repair.

Transcatheter device occlusion of multiple large pulmonary arteriovenous malformations in two symptomatic pediatric patients.

Pulmonary arteriovenous malformations (AVMs) large enough to lead to clinically significant cyanosis are rare in the pediatric population. To date, there has been some experience with transcatheter embolization of pulmonary AVMs in children, primarily with coils or balloons. Herein, we report 2 cases of children who were progressively symptomatic and had physical manifestations of hypoxemia arising from large pulmonary AVMs. Both improved after successful catheter-based placement of multiple occlusion devices (Amplatzer vascular plugs) in the pulmonary arterial segments feeding the AVMs produced a rapid, sustained increase in oxygen saturations, and a subsequent amelioration of their symptoms. This represents the first case series of multiple Amplatzer vascular plugs placed into numerous arteriovenous formations, exclusively in children. This approach represents an additional nonsurgical option for children or adults with symptomatic pulmonary AVMs.

Characteristics of the interatrial communication in patients undergoing transcatheter device closure of atrial septal defects for cryptogenic stroke.

BACKGROUND: Prior studies suggest that patent foramen ovale (PFO) diameter >4 mm is associated with a high probability of cryptogenic ischemic stroke (CIS). METHODS: We evaluated all patients diagnosed with CIS who underwent closure of intra-atrial communication (IAC) using the Amplatzer atrial septal defect (ASD) occluder in our institution between August 1997 and March 2004. For each IAC, echocardiographic diameters and balloon-stretched diameters were recorded. Stretchability index was calculated as the ratio of stretched diameter to unstretched diameter. RESULTS: Fifty-six patients met the inclusion criteria for this study. There was an inverse logarithmic relationship between unstretched IAC diameter and stretchability index. For the 28 smaller defects, the median IAC diameter was 2 mm, and median stretchability index was 5.58 (range 2.6-15). For the 28 larger defects, median diameter was 6 mm, and median stretchability index was 2.38 (range 1.05-5). The difference in stretchability index between the two groups was significant (P < 0.0001). CONCLUSION: Our data bring into question the concept that the diameter of the defect would singularly predict the probability of stroke.