Paul M. Seib

Influence of Diurnal Blood Pressure Variations on Target Organ Abnormalities in Adolescents With Mild Essential Hypertension

As hypertensive target-organ damage has been associated with diminished diurnal blood pressure (BP) variation in adults, we compared diurnal BP patterns of hypertensive adolescents with left ventricular hypertrophy with normotensive and hypertensive adolescents with normal left ventricular mass. In addition, the frequency of microalbuminuria (Malb), hyperfiltration, and reduced renal functional reserve (RFR) was evaluated in adolescents with normal BP and untreated borderline and mild essential hypertension. Thirty-three normotensive (NT) adolescents, 14.5+/-2.1 years (mean +/- SD), and 29 untreated borderline and mildly hypertensive (HT) adolescents, 14.6+/-2.4 years, wore the SpaceLabs 90207 ambulatory BP monitor for 24 h. Left ventricular mass was measured by M-mode echocardiography and then indexed (LVMI) to the cube of height. Creatinine clearance (Clcr) and urine Malb was measured on 24 h collection and RFR by change in creatinine clearance after an oral protein load. Diurnal BP change was expressed as the absolute and percent day-night BP fall and cusum derived plot height (CPH) and circadian alteration magnitude (CDCAM). Groups were compared using analysis of covariance with adjustments for race, gender, and body mass index. All NT and 19 HT subjects (HT-1) had normal LVMI at 22.2+/-5.3 and 25.8+/-3.8 g/m3, respectively. Ten HT (HT-2) had increased LVMI of 36.9+/-5.2 g/m3. No significant difference was found for absolute or percent day-night BP fall or CDCAM between groups. Nocturnal systolic BP was correlated most closely with LVMI (r = 0.41, p = .001). Clcr, Malb, and RFR did not differ between the groups. In conclusion, adolescents with borderline and mild essential hypertension and left ventricular hypertrophy have similar levels of diurnal BP fall, urine Malb excretion, and RFR compared to normotensive and hypertensive adolescents with normal left ventricular mass.

Blade and balloon atrial septostomy for left heart decompression in patients with severe ventricular dysfunction on extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is used as circulatory support or bridge to transplantation in patients with severe left ventricular (LV) dysfunction. Left heart decompression is needed to reduce pulmonary edema, prevent pulmonary hemorrhage, and reduce ventricular distention that may aid in recovery of function. We reviewed our experience from November 1993 to December 1997 with 10 patients having severe LV dysfunction (7 myocarditis, 3 dilated cardiomyopathy) who required circulatory support with ECMO and who underwent left heart decompression with blade and balloon atrial septostomy (BBAS). Patients ranged in age from 1 to 24 years (median, 3 years). Indications for BBAS included left atrial/left ventricular distension (10), pulmonary edema/hemorrhage (9), or severe mitral regurgitation (2). BBAS was performed electively in eight patients and urgently in two patients. BBAS was performed while on ECMO in seven patients and pre‐ECMO in three. A femoral venous approach was used in all patients. ECMO patients were fully heparinized. Transseptal puncture was required in nine patients while one patient had a patent foramen ovale. Blade septostomy was performed in all patients. Enlargement of the defect was then performed by stationary balloon dilation in nine and Rashkind balloon atrial septostomy in one. Balloon diameters ranged from 10 to 20 mm. Sequential balloon inflations were performed in some patients. Adequacy of the atrial septal defect (ASD) was confirmed by pressure measurement and echocardiography. Adequate left heart decompression was achieved in all patients. Pulmonary edema improved in nine of nine patients. Left atrial mean pressure fell from a mean of 30.5 mm Hg, (range, 12–50 mm Hg) to 16 mm Hg (range, 9–24 mm Hg). Left atrial to right atrial pressure gradient fell from a mean of 20 mm Hg pre‐BBAS to 3 mm Hg post‐BBAS. ASDs ranged in size from 2.5 to 8 mm (mean, 5.9 mm). Complications included needle perforation of the left atrium without hemodynamic compromise (one), ventricular fibrillation requiring defibrillation (one), and hypotension following BBAS which responded to volume infusion (two). Duration of ECMO ranged from 41 hr to 704 hr (mean, 294 hr). Seven patients survived and four patients had recovery of normal LV function. Of those who recovered, two had no ASD at follow‐up while two ASDs are patent 14 days and 3 months post‐BBAS. Three patients underwent successful cardiac transplantation. Three patients died, all of whom had multisystem organ failure with or without sepsis. A patent ASD was noted at transplant (three) or autopsy (two). No patient required a second BBAS. BBAS alleviates severe left atrial hypertension and pulmonary edema. In addition, BBAS avoids the potential bleeding complications of surgical left heart decompression. Stationary balloon dilation of the atrial septum is an effective alternative to Rashkind balloon septostomy in older patients. BBAS achieves left heart decompression that may permit recovery of LV function or allow extended ECMO support as a bridge to transplant. Cathet. Cardiovasc. Intervent. 46:179–186, 1999.

Noninvasive Cerebral Oximeter as a Surrogate for Mixed Venous Saturation in Children

We evaluated the relationship between regional cerebral oxygen saturation (rSO2) measured by near-infrared spectroscopy (NIRS) cerebral oximeter with superior vena cava (SVC), inferior vena cava (IVC), right atrium (RA), and pulmonary artery (PA) saturation measured on room air and 100% inspired oxygen administered via a non-rebreather mask (NRB) in children. Twenty nine pediatric post-orthotopic heart transplant patients undergoing an annual myocardial biopsy were studied. We found a statistically significant correlation between rSO2 and SVC saturations at room air and 100% inspired oxygen concentration via NRB (r = 0.67, p = 0.0002 on room air; r = 0.44, p = 0.02 on NRB), RA saturation (r = 0.56, p = 0.002; r = 0.56, p = 0.002), and PA saturation (r = 0.67, p < 0.001; r = 0.4, p = 0.03). A significant correlation also existed between rSO2 and measured cardiac index (r = 0.45, p = 0.01) and hemoglobin levels (r = 0.41, p = 0.02). The concordance correlations were fair to moderate. Bias and precision of rSO2 compared to PA saturations on room air were −0.8 and 13.9%, and they were 2.1 and 15.6% on NRB. A stepwise linear regression analysis showed that rSO2 saturations were the best predictor of PA saturations on both room air (p = 0.0001) and NRB (p = 0.012). In children with biventricular anatomy, rSO2 readings do correlate with mixed venous saturation.

Prolonged extracorporeal life support for bridging to transplant: technical and mechanical considerations.

Through July 1995, the Extracorporeal Life Support Organization (ELSO) registry listed 87 patients who received extracorporeal life support (ECLS) as a bridge to cardiac transplantation with a survival rate of 41%. At Arkansas Children’s Hospital, 17 patients (aged between two days and 24 years) with diagnoses of dilated cardiomyopathy (seven), postcardiotomy (seven) and acute viral myocarditis (three) were bridged with ECLS. Mechanical complications only occurred in two patients, neither of which necessitated withdrawal of ECLS. Decompression of the left heart was performed in 11 patients, six via a surgically placed vent and five with a blade/balloon atrial septostomy. Documented infection occurred in 11/17 patients, but only one patient died from infection. Fifteen of 17 patients (88%) recovered or were transplanted, of which 13 (76%) were discharged home. With left-heart decompression and appropriate treatment of infection, ECLS may be used as a bridge to cardiac transplantation or until the return of cardiac function.

Long-term outcomes of intraoperative pulmonary artery stent placement for congenital heart disease

Objective:Our objective was to examine long‐term outcomes of intraoperative pulmonary artery stents and determine risk factors for reintervention Background:Short‐term outcomes of intraoperative pulmonary artery stents have been reported previously. However, long‐term results are unknown. Methods: We conducted a retrospective review of patients who underwent intraoperative pulmonary artery stent placement for branch pulmonary artery stenosis. Results: Ninety‐six stents were implanted intraoperatively in 67 patients. Twenty‐seven patients received two or more stents at initial intervention. Median patient age at initial stent placement was 1.8 years. Median post‐inflation diameter was 8 mm. At a mean follow‐up of 7.6 ± 4.5 years, 49% of stents required reintervention (balloon angioplasty at catheterization in 28 patients and surgical revision in 19 patients). Actuarial freedom from reintervention at 2, 5, and 10 years was 68%, 49%, and 40%, respectively. In univariate analysis of time to first reintervention, age at implantation < 2 yrs (P < 0.0009) and initial post‐inflation stent diameter < 10 mm (P < 0.0002) were associated with risk for reintervention. Multivariable Cox regression analysis showed age < 2 years (P < 0.005) and diagnosis of tetralogy of Fallot (p < 0.002) or truncus arteriosus (P < 0.007) to be significant risk factors for reintervention. Conclusion: Intraoperative placement of stents in the pulmonary arteries is an alternative to surgical angioplasty, but is associated with a high incidence of reintervention. Age < 2 years and the diagnosis of tetralogy of Fallot or truncus arteriosus are risk factors for reintervention.

Intrahospital transport of children on extracorporeal membrane oxygenation: Indications, process, interventions, and effectiveness

Objective: To evaluate indications, process, interventions, and effectiveness of patients undergoing intrahospital transport. Critically ill patients supported with extracorporeal membrane oxygenation are transported within the hospital to the radiology suite, cardiac catheterization suite, operating room, and from one intensive care unit to another. No studies to date have systematically evaluated intrahospital transport for patients on extracorporeal membrane oxygenation. Design: Retrospective cohort analysis. Setting: Cardiac intensive care unit in a tertiary care childrens hospital. Patients: All patients on extracorporeal membrane oxygenation who required intrahospital transport between January 1996 and March 2007 were included and analyzed. Measurements and Main Results: A total of 57 intrahospital transports for cardiac catheterization and head computed tomography scans were analyzed. In 14 (70%) of 20 of patients with cardiac catheterization, a management change occurred as a result of the diagnostic cardiac catheterization. In ten (59%) of 17 patients, bedside echocardiography was of limited value in defining the critical problem. In the interventional group, the majority of transports were for atrial septostomy. In the head computed tomography group, significant pathology was identified, which led to management change. No major complications occurred during these intrahospital transports. Conclusions: Although transporting patients on extracorporeal membrane oxygenation is labor intensive and requires extensive logistic support, it can be carried out safely in experienced hands and it can result in important therapeutic and diagnostic yields. To our knowledge, this is the first study designed to evaluate safety and efficacy of intrahospital transport for patients receiving extracorporeal membrane oxygenation support.

Doppler tissue imaging and catheter-derived measures are not independent predictors of rejection in pediatric heart transplant recipients

The purpose of the study is to determine the association of Doppler Tissue Imaging (DTI) and catheter-derived measures with rejection in pediatric heart transplant (PHT) recipients and to determine any correlation between DTI and catheter-derived measurements. Sixty echocardiograms were prospectively performed in 37 PHT recipients at the time of surveillance cardiac biopsy. During right-heart cardiac catheterization, sequential pressures of the right heart and pulmonary capillary wedge pressures (PCWP) were measured. DTI was performed to obtain peak systolic (S’), early (E’) and late (A’) diastolic velocities (cm/s) at tricuspid annulus, septum and mitral annulus. Septal S’ and tricuspid annular A’ were associated with rejection, but had low sensitivity and specificity. Elevated lateral mitral E/E’ did not predict rejection. The mean pulmonary capillary wedge pressure (PCWP) and cardiac index were similar in those with and without rejection. The lateral mitral and septal E/E’ did not correlate with PCWP. Some DTI-derived measures were altered during rejection, but were not clinically useful predictors of rejection. Catheter-derived measures were not significantly altered during rejection and did not correlate with DTI-derived measures. None of these measures can replace the current practice of performing cardiac biopsy for surveillance of rejection.

Percutaneous coronary intervention using drug‐eluting stents in pediatric heart transplant recipients

Abstract:  PCI has been used for palliation of CAV in adults, but there are limited data available in children. We sought to evaluate our experience with PCIs for CAV in pediatric heart transplant recipients. Retrospective review of the medical records of all four patients who were diagnosed with CAV, including demographic data and catheterization reports was performed. Of the 149 pediatric heart transplant recipients followed at our institution, 10 were identified with CAV. Four of these 10 underwent 12 PCI procedures for CAV. One donor heart had documented coronary artery disease. Two patients had significant risk factors for coronary artery disease including morbid obesity, hyperlipidemia, and systemic hypertension. PCI involved deployment of bare metal stents (n = 2), paclitaxel‐eluting stent (n = 6), and sirolimus‐eluting stents (n = 4) with procedural success in all and no early or late mortality. One procedure was complicated by coronary dissection that was successfully treated with stent placement. One patient has been re‐transplanted while the other three are not candidates for re‐transplantation and have remained asymptomatic as palliation with PCI. PCI using coronary stents is a safe and effective palliative measure for CAV in pediatric heart transplant recipients.

Stenting for superior vena cava obstruction in pediatric heart transplant recipients

Superior vena cava (SVC) obstruction can be a complication in heart transplant recipients. We reviewed our experience with relief of SVC obstruction using endovascular stents in pediatric heart transplant recipients.

Management of a pediatric patient on the Berlin Heart Excor ventricular assist device with argatroban after heparin-induced thrombocytopenia.

We report a 15-year-old male patient who developed type II heparin-induced thrombocytopenia (HIT) after 6 weeks of heparin administration and placement of a Berlin Heart Excor left ventricular assist device (LVAD).