Hemodynamic Effects of Phenylephrine, Vasopressin, and Epinephrine in Children With Pulmonary Hypertension: A Pilot Study.

OBJECTIVES: During a pulmonary hypertensive crisis, the marked increase in pulmonary vascular resistance can result in acute right ventricular failure and death. Currently, there are no therapeutic guidelines for managing an acute crisis. This pilot study examined the hemodynamic effects of phenylephrine, arginine vasopressin, and epinephrine in pediatric patients with pulmonary hypertension. DESIGN: In this prospective, open-label, nonrandomized pilot study, we enrolled pediatric patients previously diagnosed with pulmonary hypertensive who were scheduled electively for cardiac catheterization. Primary outcome was a change in the ratio of pulmonary-to-systemic vascular resistance. Baseline hemodynamic data were collected before and after the study drug was administered. PATIENTS: Eleven of 15 participants were women, median age was 9.2 years (range, 1.7-14.9 yr), and median weight was 26.8 kg (range, 8.5-55.2 kg). Baseline mean pulmonary artery pressure was 49 ± 19 mm Hg, and mean indexed pulmonary vascular resistance was 10 ± 5.4 Wood units. Etiology of pulmonary hypertensive varied, and all were on systemic pulmonary hypertensive medications. INTERVENTIONS: Patients 1-5 received phenylephrine 1 µg/kg; patients 6-10 received arginine vasopressin 0.03 U/kg; and patients 11-15 received epinephrine 1 µg/kg. Hemodynamics was measured continuously for up to 10 minutes following study drug administration. MEASUREMENTS AND MAIN RESULTS: After study drug administration, the ratio of pulmonary-to-systemic vascular resistance decreased in three of five patients receiving phenylephrine, five of five patients receiving arginine vasopressin, and three of five patients receiving epinephrine. Although all three medications resulted in an increase in aortic pressure, only arginine vasopressin consistently resulted in a decrease in the ratio of systolic pulmonary artery-to-aortic pressure. CONCLUSIONS: This prospective pilot study of phenylephrine, arginine vasopressin, and epinephrine in pediatric patients with pulmonary hypertensive showed an increase in aortic pressure with all drugs although only vasopressin resulted in a consistent decrease in the ratio of pulmonary-to-systemic vascular resistance. Studies with more subjects are warranted to define optimal dosing strategies of these medications in an acute pulmonary hypertensive crisis.

Exploring the Role of Polycythemia in Patients With Cyanosis After Palliative Congenital Heart Surgery.

OBJECTIVES: To understand the relationship between polycythemia and clinical outcome in patients with hypoplastic left heart syndrome following the Norwood operation. DESIGN: A retrospective, single-center cohort study. SETTING: Pediatric cardiovascular ICU, university-affiliated children's hospital. PATIENTS: Infants with hypoplastic left heart syndrome admitted to our medical center from September 2009 to December 2012 undergoing stage 1/Norwood operation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Baseline demographic and clinical information including first recorded postoperative hematocrit and subsequent mean, median, and nadir hematocrits during the first 72 hours postoperatively were recorded. The primary outcomes were in-hospital mortality and length of hospitalization. Thirty-two patients were included in the analysis. Patients did not differ by operative factors (cardiopulmonary bypass time and cross-clamp time) or traditional markers of severity of illness (vasoactive inotrope score, lactate, saturation, and PaO2/FIO2 ratio). Early polycythemia (hematocrit value > 49%) was associated with longer cardiovascular ICU stay (51.0 [± 38.6] vs 21.4 [± 16.2] d; p < 0.01) and total hospital length of stay (65.0 [± 46.5] vs 36.1 [± 20.0] d; p = 0.03). In a multivariable analysis, polycythemia remained independently associated with the length of hospitalization after controlling for the amount of RBC transfusion (weight, 4.36 [95% CI, 1.35-7.37]; p < 0.01). No difference in in-hospital mortality rates was detected between the two groups (17.6% vs 20%). CONCLUSIONS: Early polycythemia following the Norwood operation is associated with longer length of hospitalization even after controlling for blood cell transfusion practices. We hypothesize that polycythemia may be caused by hemoconcentration and used as an early marker of capillary leak syndrome.

Mitral Stenosis and Aortic Atresia--A Risk Factor for Mortality After the Modified Norwood Operation in Hypoplastic Left Heart Syndrome.

BACKGROUND: There are conflicting reports regarding the importance of mitral stenosis and aortic atresia as a risk factor for Norwood mortality. This study reviews outcomes of this anatomic subgroup at our institution and examines the utility of preoperative cardiac catheterization and its correlation with clinical outcomes and pathology findings. METHODS: This is a single-center, retrospective review of hypoplastic left heart syndrome patients who underwent modified Norwood operation between October 2005 and May 2013. RESULTS: Fourteen of 74 hypoplastic left heart syndrome patients (19%) had mitral stenosis and aortic atresia. Operative mortality for MS/AA was 29% versus 7% for all other hypoplastic left heart syndrome anatomic subgroups (p = 0.04). Although only 19% of the entire cohort, the mitral stenosis and aortic atresia subgroup constituted 50% of the total operative mortality and the only interstage deaths. Autopsies support myocardial ischemia as the mechanism of death. Although preoperative angiography defined the presence of ventriculo-coronary connections, it did not clearly risk stratify patients in regard to operative mortality. CONCLUSIONS: Mitral stenosis and aortic atresia is a risk factor for perioperative myocardial ischemia and mortality. Further exploration of myocardial reserve is warranted.

Training Pathways in Pediatric Cardiac Intensive Care: Proceedings From the 10th International Conference of the Pediatric Cardiac Intensive Care Society.

The increase in pediatric cardiac surgical procedures and establishment of the practice of pediatric cardiac intensive care has created the need for physicians with advanced and specialized knowledge and training. Current training pathways to become a pediatric cardiac intensivist have a great deal of variability and have unique strengths and weaknesses with influences from critical care, cardiology, neonatology, anesthesiology, and cardiac surgery. Such variability has created much confusion among trainees looking to pursue a career in our specialized field. This is a report with perspectives from the most common advanced fellowship training pathways taken to become a pediatric cardiac intensivist as well as various related topics including scholarship, qualifications, and credentialing.

COCATS 4: Securing the Future of Cardiovascular Medicine.

The latest iteration of the Core Cardiology Training Statement (COCATS 4) [Corrected] provides a potentially transformative advancement in cardiovascular fellowship training intended, ultimately, to improve patient care. This review addressed 3 primary themes of COCATS 4 from the perspective of fellows-in-training: 1) the evolution of training requirements culminating in a competency-based curriculum; 2) the development of novel learning paradigms; and 3) the establishment of task forces in emerging areas of multimodality imaging and critical care cardiology. This document also examined several important challenges presented by COCATS 4. The proposed changes in COCATS 4 should not only enhance the training experience but also improve trainee satisfaction. Because it embraces continual transformation of training requirements to meet evolving clinical needs and public expectations, COCATS 4 will enrich the cardiovascular fellowship training experience for patients, programs, and fellows-in-training.

Reported sildenafil side effects in pediatric pulmonary hypertension patients.

BACKGROUND: Sildenafil, a phosphodiestase type 5 inhibitor, was approved in 2005 for the treatment of pulmonary arterial hypertension (PAH) in adults and is commonly used off-label for pediatric patients. Little is known, however, about sildenafil's side effects in this population. METHODS: Single institution, longitudinal survey-based study performed in an outpatient pediatric cardiology clinic. Pediatric patients on sildenafil [alone or in combination with other pulmonary hypertension (PH) therapies] completed questionnaires regarding frequency of vascular, gastrointestinal, neurologic, and hematologic side effects. RESULTS: Between January 2011 and May 2014, 66 pediatric patients with PH on sildenafil filled out 214 surveys, 32 patients (96 surveys) on monotherapy, and 43 patients (118 surveys) on sildenafil plus an endothelin receptor antagonist (ERA) (bosentan or ambrisentan) and/or a prostacyclin (epoprostenol or treprostinil). Overall, 30% of respondents identified at least one side effect. For all patients on sildenafil, incidence of side effects by system was 37% gastrointestinal, 35% vascular, and 22% neurologic. For patients on sildenafil monotherapy, incidence of side effects by system was 24% gastrointestinal, 21% vascular, and 18% neurologic compared to patients on combination therapy who reported an incidence of 48% gastrointestinal, 45% vascular, and 25% neurologic. CONCLUSION: Incidence of vascular, gastrointestinal, and neurologic side effect in pediatric patients on sildenafil therapy for PAH was 30%. Side effects were more common in patients on combination therapy with an ERA and/or prostacyclin than in patients on sildenafil monotherapy.

Ebstein anomaly and Trisomy 21: A rare association.

This is a case report of a patient with Trisomy 21 with Ebstein anomaly, a ventricular septal defect, and acquired pulmonary vein stenosis; a rare combination, diagnosed during a routine neonatal examination.

Outcomes following cardiac catheterization after congenital heart surgery.

OBJECTIVES: Describe outcomes following unplanned cardiac catheterization after congenital heart surgery. BACKGROUND: Utility of cardiac catheterization following congenital heart surgery is relatively understudied. METHODS: Retrospective study examining demographics, indications, and outcomes of unplanned cardiac catheterization after congenital heart surgery at a single institution. RESULTS: Between October 2004 and April 2011, 120 patients underwent 150 unplanned postoperative cardiac catheterizations. Median day of catheterization was postoperative day 20 (range 1-269 days). Survival 30 days postcatheterization was 85%; overall survival to hospital discharge was 72%. Indications for catheterization: 63 for hemodynamic evaluation, 46 for likely intervention, and 41 for assessment of surgical repair. Of the 150 hemodynamic/interventional catheterizations, 103 (69%) were associated with a change in clinical management: 59 trans-catheter interventions, 22 re-operations, 11 changes in medication, six changes in surgical plan, and five withdrawals of support. Complications included hemorrhage in two patients, supraventricular tachycardia in two patients, and transient complete heart block requiring cardiopulmonary resuscitation in one patient. CONCLUSIONS: Cardiac catheterization following congenital heart surgery may enable important diagnostic and therapeutic changes in clinical and surgical management. Complications were rare.

Home monitoring program reduces interstage mortality after the modified Norwood procedure.

BACKGROUND: From 2002 to 2005, the interstage mortality after a modified Norwood procedure was 7% in our program. An interstage home monitoring program (HMP) was established to identify Norwood procedure patients at increased risk of decompensation and to reduce interstage mortality. METHODS: Results of the first 5 years of the Norwood HMP were reviewed retrospectively. Interstage was defined as the time between Norwood hospital discharge and admission for second stage surgical palliation. In the HMP, families documented oxygen saturation, heart rate, weight, and feedings daily. Nurse practitioners called each family at least weekly, and when issues arose, action plans were determined based on symptom severity. RESULTS: Between October 2005 and October 2010 there were 46 Norwood procedure patients who survived to hospital discharge. All were enrolled in the HMP. Forty-five patients had a Norwood procedure with right ventricle to pulmonary artery conduit, and 1 patient had a modified Blalock-Taussig shunt. Interstage survival was 100%. Nineteen patients (41%) were admitted interstage; 5 patients were admitted twice, 1 patient was admitted 4 times. Seventeen patients (37%) required interstage interventions. Eight patients (17%) required major interventions: conduit stenting, aortic arch balloon angioplasty, emergent shunt, or early Glenn surgery. Minor interventions included supplemental oxygen, blood transfusion, intravenous hydration, diuresis, anti-arrhythmic therapy, or feeding adjustments. CONCLUSIONS: In the first 5 years of the HMP, all infants discharged after a modified Norwood procedure survived the interstage period. The HMP altered clinical management in 37% of patients. Home monitoring of oxygen saturation, heart rate, weight, and feedings, along with comprehensive care coordination, allowed timely interventions and reduced interstage mortality from 7% to 0%.

Incidence and risk factors of complete atrioventricular block after operative ventricular septal defect repair.

BACKGROUND: Complete atrioventricular block (AVB) is a recognized complication of ventricular septal defect (VSD) repair. The objective of this study was to examine incidence and risk factors. METHODS: This is a single-center, retrospective study. All pediatric patients (age <18 years) who underwent VSD repair between November 2001 and August 2009 with concordant atrioventricular and ventriculoarterial connections were included. Patients were classified as having no AVB or transient AVB, and outcomes of early pacemaker placement (before hospital discharge) or late pacemaker placement (after hospital discharge) were recorded. RESULTS: Eight hundred twenty-eight patients (48.6% female) underwent VSD repair during the study period. Mean age at repair was 14 ± 29.4 months. A total of 64 patients (7.7%) developed surgical AVB. Among those patients who developed AVB, 48 (75%) had transient AVB. Sixteen patients (1.9%) required a pacemaker, 14 early (88%) and 2 late (12%). Patients <4 kg (4.2% vs. 1%, P ≤ .01) and those with inlet VSDs (11.6% vs. 1.4%, P ≤ .01) were more likely to develop surgical AVB. Surgical AVB was not influenced by the presence of chromosomal abnormalities or other congenital heart disease. CONCLUSION: The overall incidence of surgical AVB is consistent with previous reports. Weight <4 kg and presence of an inlet VSD were significant risk factors.

Orthotopic heart transplantation in two infants with histiocytoid cardiomyopathy and left ventricular non-compaction.

HC is a rare cause of congestive heart failure that typically presents with malignant ventricular arrhythmias in infants, often requiring urgent intervention. Successful heart transplantation in a patient with HC has only been reported once (J Heart Lung Transplant 2004: 23: 902). The combination of HC with concurrent LVNC has only been described three times (Int J Legal Med 2009: 123: 47; Hum Pathol 2005: 36: 403; Pediatr Dev Pathol 2012: 15: 397). We report two rare cases of HC with LVNC in two infants presenting with cardiogenic shock, one requiring ECMO support who was successfully bridged to orthotopic heart transplantation with a Berlin Heart LVAD.

Children with pulmonary arterial hypertension and prostanoid therapy: long-term hemodynamics.

BACKGROUND: Pediatric patients with severe pulmonary arterial hypertension (PAH) are treated with intravenous epoprostenol or intravenous or subcutaneous treprostinil. Little is known about longitudinal hemodynamics and outcomes of epoprostenol, treprostinil, and transitions from epoprostenol to treprostinil. METHODS: This was retrospective study of 77 pediatric patients (47 idiopathic PAH, 24 congenital heart disease-PAH) receiving epoprostenol or treprostinil from 1992 to 2010 at 2 centers. Outcomes were defined as living vs dead/transplant. RESULTS: Mean age at baseline was 7.7 ± 5.2 years, with follow-up of 4.3 ± 3.4 years. Thirty-seven patients were treated with epoprostenol, 20 with treprostinil, and 20 were transitioned from epoprostenol to treprostinil. Mean pulmonary-to-systemic vascular resistance ratio (Rp/Rs) for epoprostenol was 1.0 ± 0.4, 0.8 ± 0.4, 0.8 ± 0.4, 1.0 ± 0.4, and 1.2 ± 0.4, respectively, at baseline, 1, 2, 3, and 4 years. For treprostinil, Rp/Rs was 0.9 ± 0.3, 0.7 ± 0.3, 0.5 ± 0.2, (p < 0.01 vs baseline), and 1.1 ± 0.2, respectively, at baseline, 1, 2, and 3 to 4 years, respectively. There were similar changes in mean pulmonary artery pressure and pulmonary vascular resistance index. The Rp/Rs 1 year after epoprostenol to treprostinil transition increased from 0.6 to 0.8 (n = 7). Changes not statistically significant unless noted. Eight patients died or received a transplant within 2 years of baseline; compared with the rest of the cohort, mean baseline Rp/Rs, right atrial pressure, and pulmonary vascular resistance index were significantly worse in this group. Thirty-nine patients remain on prostanoids, 17 are off, 16 died, and 5 received heart-lung transplant. Kaplan-Meier 5-year transplant-free survival was 70% (95% confidence interval, 56%-80%). CONCLUSION: There was improvement in Rp/Rs on both therapies at 1 to 2 years that was not sustained. The 5-year transplant-free survival was better than in similar adult studies.

Electrical and mechanical dyssynchrony in pediatric pulmonary hypertension.

BACKGROUND: Electrical and mechanical dyssynchrony are often seen in patients with left ventricular failure. In pediatric pulmonary hypertension (PH), right ventricular failure predominates; however, the prevalence of electrical and/or mechanical dyssynchrony in these patients is unknown. We examined the prevalence of electrical and mechanical dyssynchrony in pediatric PH patients. METHODS: Medical records (including, functional status, electrocardiograms and echocardiograms) of pediatric PH patients were reviewed. QRS duration z-scores were calculated to determine electrical dyssynchrony. Echo vector velocity imaging was used to calculate the mechanical dyssynchrony index (DI). RESULTS: Seventy-seven PH patients (idiopathic pulmonary arterial hypertension [IPAH]: n = 26; congenital heart disease: n = 41; other: n = 10) were studied. Electrical dyssynchrony was seen in 84% (p < 0.01 vs historic controls), with a mean z-score of 4.3 (95% CI 3.5 to 5.1). There was no difference between those with IPAH, z = 3.6 (95% CI 2.5 to 4.6), and those without, z = 4.7 (95% CI 3.6 to 5.8). Mechanical dyssynchrony was seen in 76% of patients (mean DI = 66 ± 47 vs 18 ± 8 milliseconds in historic controls, p < 0.01) in both IPAH and non-IPAH patients. Post-operative congenital heart disease patients had the largest dyssynchrony index. No correlation was found among electrical or mechanical dyssynchrony, hemodynamics or disease severity. CONCLUSIONS: Significant electrical and mechanical dyssynchrony is present in pediatric PH patients, regardless of etiology. The overall effect of electrical and mechanical dyssynchrony on outcomes in this patient population is still unknown. Select patients may benefit from resynchronization therapy.

Clinical usefulness of a novel C1q assay to detect immunoglobulin G antibodies capable of fixing complement in sensitized pediatric heart transplant patients.

BACKGROUND: Donor-specific antibodies (DSA) against human leukocyte antigens complicate transplantation with the potential for acute antibody-mediated rejection (AMR). Complement-fixing antibodies are required to initiate the complement cascade. Not all DSAs, however, can fix complement. METHODS: A novel C1q assay was developed to detect the sub-set of immunoglobulin G (IgG) antibodies capable of fixing complement. Sera from 18 pediatric heart transplant patients were analyzed for DSAs using a Luminex platform (Luminex Inc, Austin, TX) and commercially available single-antigen bead assay kits. Biopsy specimens were assessed for AMR using histopathologic criteria and immunohistochemical staining. RESULTS: During the study period, 5 patients had AMR; of these, 2 were C1q virtual crossmatch positive (VXM+) and had persistent C1q DSAs after transplant, and 3 were C1q VXM- but antibody developed immediately after transplant. A positive C1q assay in the immediate post-transplant period had a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 100%, with 100% sensitivity and 100% specificity (Fisher exact p = 0.001). Of 11 patients who were IgG VXM+, 5 had AMR; the IgG VXM had a PPV of 45% and NPV of 100%, with 100% sensitivity and 54% specificity (Fisher exact p = 0.101). CONCLUSIONS: The C1q assay can detect a sub-set of antibodies capable of fixing complement and predicts AMR early after transplant. Avoiding only the donor antigens that would be recognized by the C1q assay may accelerate time to transplant by expansion of the donor pool and potentially allows transplantation of previously "incompatible" organs.

Hypersensitivity reactions to aprotinin re-exposure in paediatric surgery.

OBJECTIVE: Hypersensitivity to aprotinin is low (1-3%) but more likely with re-exposure. The manufacturer issued a black box warning which lists aprotinin re-exposure within 1 year of prior exposure as a contraindication. We investigated the temporal relationship between re-exposure interval and hypersensitivity in children. METHODS: With Human Research Review Board approval, charts of all patients exposed to aprotinin during cardiac surgery were reviewed. We extracted data for re-exposure interval and hypersensitivity to skin tests, intravenous test dosing or infusion of the loading dose. We defined systemic hypersensitivity as haemodynamic instability, respiratory symptoms or diffuse skin reaction temporally related to exposure. RESULTS: From March 1994 to June 2007, there were a total of 2333 aprotinin exposures in 1824 patients. A total of 509 re-exposures occurred in 381 patients: 280 in 244 patients with early (within 1 year) re-exposure and 229 in 222 patients with late (after 1 year) re-exposure. Thirteen systemic hypersensitivity reactions occurred in the 509 re-exposures (2.6%): two during skin testing and 11 during the loading dose. Although the incidence of local hypersensitivity was increased with early re-exposure (6/280 or 2.1% vs 0/229, p=0.019), the incidence of the systemic reaction was not different between early and late re-exposures (6/280 or 2.1% (CI 0.8-4.6%) vs 7/229 or 3.1% (CI 1.2-6.2%), p=0.6). Six patients with a previous hypersensitivity reaction had an additional re-exposure to aprotinin; one of these patients had a systemic reaction during the third exposure. CONCLUSION: The incidence and type of hypersensitivity to aprotinin re-exposure in our cohort is consistent with previous reports. Repeat exposure within 1 year did not increase the risk of systemic hypersensitivity.

Early cavopulmonary anastomosis after Norwood procedure results in excellent Fontan outcome.

BACKGROUND: Children with univentricular hearts and aortic arch obstruction are treated sequentially with Norwood procedure, superior cavopulmonary anastomosis (SCPA), and Fontan operation. Early SCPA results in lower initial O2 saturation and longer hospitalization, but not increased mortality. We sought to determine the impact of early SCPA on Fontan candidacy and outcomes. METHODS: Eighty-five consecutive patients undergoing Norwood operation between January 1998 and February 2003 were divided into group 1 (SCPA at less than 4 months, n = 33) and group 2 (SCPA at more than 4 months, n = 52). Of the original cohort, 69 have undergone Fontan operation, 7 await Fontan, 1 was transplanted, 3 are not Fontan candidates, and 5 died late after SCPA. Group 1 (n = 25) and group 2 (n = 44) patients who have completed Fontan operation were compared for preoperative and perioperative variables: age, size, O2 saturation, pulmonary artery pressure and size, prevalence of tricuspid regurgitation and ventricular dysfunction, extubation rate in operating room, duration of pleural drainage, hospital stay, and discharge O2 saturation. Late functional status and ventricular function were also compared. Survival was compared for original groups 1 and 2. RESULTS: There were no differences for any preoperative or perioperative variable, or late functional assessment. Actuarial survival at 6 years was also not different (88% +/- 5% for group 1 and 94% +/- 4% for group 2, p = 0.72). CONCLUSIONS: Although initially more cyanotic and hospitalized longer than older peers, younger SCPA patients achieve clinical equivalence by the time of Fontan operation and afterward. We conclude that both short- and long-term outcomes support performance of early SCPA.