Michael D. Seckeler

The worldwide epidemiology of acute rheumatic fever and rheumatic heart disease

Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) are significant public health concerns around the world. Despite decreasing incidence, there is still a significant disease burden, especially in developing nations. This review provides background on the history of ARF, its pathology and treatment, and the current reported worldwide incidence of ARF and prevalence of RHD.

The persistent challenge of rheumatic fever in the Northern Mariana Islands.

OBJECTIVES Acute rheumatic fever (ARF) is a major cause of morbidity and mortality in developing nations. The objective of this study was to determine the disease burden of ARF among the indigenous and non-indigenous populations of the Northern Mariana Islands. METHODS This was a chart review of all pediatric outpatients seen from 1984 to 2006 with ICD-9 codes corresponding to rheumatic fever or any rheumatic cardiac sequelae. The study was set in the only comprehensive inpatient facility and only public pediatric clinic in the Northern Mariana Islands. RESULTS One hundred fifty-eight cases of ARF were identified. Age at diagnosis ranged from 2.9 to 17.1 years (median 10.6 years). Fever and carditis were the most common presenting findings. The average annualized incidence of ARF was 85.8 per 100,000 person-years for those aged 5-14 years. Sixty-six percent of patients with ARF were of Chamorro or Carolinian ancestry, despite comprising only 39% of the total population, with a combined average annualized incidence of ARF of 167 per 100,000 person-years. CONCLUSIONS This is the first documentation of the incidence of pediatric ARF in the Northern Mariana Islands, delineating the large disease burden in the indigenous and other Pacific Island ethnic groups. Impediments to diagnosis and primary and secondary prevention were identified. The data provide strong support for the need for primary and secondary prevention of ARF.

Diagnosis of occult diastolic dysfunction late after the Fontan procedure using a rapid volume expansion technique

Objectives Diastolic dysfunction (DD), a key driver of long-term Fontan outcomes, may be concealed during standard haemodynamic evaluation. We sought to identify Fontan patients with occult DD using ‘ventricular stress testing’ with rapid volume expansion (RVE). Methods Cardiac catheterisation with RVE was performed routinely in Fontan patients between 11/2012 and 4/2015. Baseline and post-stress haemodynamic data were compared using t test, Mann–Whitney U test, χ2 and Fishers exact tests. A post-stress ventricular end diastolic pressure (EDP) threshold of 15 mm Hg defined occult DD. Results Forty-six Fontan patients (48% female, median age 14.1 (IQR 9.1 to 21.3) years) were included. The median Fontan duration was 10.8 (IQR 5.1 to 17.8) years and dominant left ventricular morphology was present in 63% of patients. Volume expansion increased mean Fontan pressure (15.2±2.5 vs 12.4±2.2 mm Hg, p<0.001), pulmonary capillary wedge pressure (11.3±2.6 vs 7.9±2 mm Hg, p<0.001) and EDP (12.7±3.3 vs 8.5±2.1 mm Hg, p<0.001). Sixteen patients (35%) had occult DD, demonstrating higher baseline EDP (10.3±1.9 vs 7.6±1.5 mm Hg, p<0.001) and greater increase in EDP (6.3±2.4 vs 3.1±1.4 mm Hg, p<0.001) compared with patients without DD. Higher baseline EDP, lower baseline cardiac index and longer duration of Fontan circulation were associated with higher post-stress EDP. There were no complications related to RVE. Conclusions Ventricular stress testing by RVE is feasible, safe and identifies a subgroup of Fontan patients with occult DD. Higher baseline EDP and longer duration of Fontan circulation are associated with worse diastolic function. Future work is necessary to better understand the aetiology, associations and clinical implications of occult DD in Fontan survivors.

Pulmonary Artery and Conduit Reintervention Rates After Norwood Using a Right Ventricle to Pulmonary Artery Conduit

BACKGROUND There is a high incidence of cardiovascular reinterventions in patients undergoing a Norwood procedure (NP). The goal of this study was to analyze the rate of pulmonary artery (PA) and conduit stenosis using the right ventricle (RV)-to-PA modification of the NP. METHODS Patients who underwent a NP January 2005 to December 2009 were included. The procedure was performed with a ringed conduit sutured to a membrane to form a patch. The patch was sutured to the PA confluence, and the spatulated conduit was anastomosed to an appropriately sized right ventriculotomy. Rates of PA and conduit stenosis requiring reintervention were calculated based on cardiac catheterization data. RESULTS Thirty-three patients with hypoplastic left heart syndrome underwent a NP. Perioperative mortality was 6% (2 of 33). Twenty-eight patients (85%) had a Glenn procedure 5 ± 1 months later, and 12 patients (36%) had a Fontan procedure 34 ± 2 months after the Glenn. Pulmonary artery stenosis occurred in 11 patients (33%), and RV-PA conduit stenosis occurred only in 2 patients (6%). One-year and 3-year actuarial survival rates were 82% and 77%, respectively. Both branch PAs showed good and symmetric growth at cardiac catheterization before Glenn. CONCLUSIONS The NP with RV-PA conduit using a ringed graft and a pulmonary patch is a technique associated with a low rate of PA and conduit stenosis, and good outcomes.

A new predictive equation for oxygen consumption in children and adults with congenital and acquired heart disease

Objective To develop a new predictive equation for oxygen consumption (VO2) in children and adults with congenital and acquired heart disease. Methods We retrospectively reviewed data from 502 consecutive patients (age 0–59 years) undergoing cardiac catheterisation with measured VO2 (M-VO2) and compared M-VO2 with VO2 from the LaFarge equations (LF-VO2) in patients <3 years (Group 1) and ≥3 years (Group 2). Factors associated with inaccurate LF-VO2 were used to develop a new predictive equation, which was prospectively validated in 100 consecutive patients (age 0–59 years). Results LF-VO2 was inaccurate in 42% of Group 1 (n=201) and 13% of Group 2 (n=301). Multivariable predictors of inaccurate LF-VO2 included age (OR 0.41, p=0.01) and single ventricle anatomy (OR 2.98, p=0.03) in Group 1 and anaemia (OR 0.84, p<0.001) in Group 2. Critical illness was borderline significant in both groups. The new predictive equation for VO2: Intraclass correlation between M-VO2 and the new predictive equation was good (r=0.53), whereas LF-VO2 was not (r=0.17). Bland-Altman analysis comparing M-VO2 with the new equation and with LF-VO2 demonstrated superiority of the new equation (mean bias 2.5 mL/min/m2 vs −5.0 mL/min/m2; limits of agreement −51.6, 56.5 vs −82.1, 72). Conclusions VO2 derived from the LaFarge equations is frequently inaccurate, particularly in younger patients, and will lead to erroneous haemodynamic calculations. We developed and prospectively validated a new VO2 predictive equation for use in patients of all ages with congenital and acquired heart disease.

Validation of Cardiac Output Using Real-time Measurement of Oxygen Consumption during Cardiac Catheterization in Children Under 3 Years of Age

OBJECTIVE To validate a method for determination of cardiac index (CI) using real-time measurement of oxygen consumption (VO2 ) in young children undergoing cardiac catheterization. DESIGN Retrospective review comparing thermodilution cardiac index (TDCI) to CI calculated by the Fick equation using real-time measured VO2 (RT-VO2 ) and VO2 derived from 2 published predictive equations. Paired t-test and Bland-Altman analysis were used to compare TDCI to Fick CI. A survey to ascertain pediatric cardiac catheterization practices regarding VO2 determination was also conducted. SETTING Quaternary care childrens hospital cardiac catheterization laboratory. PATIENTS Children <3 years old with structurally normal hearts undergoing cardiac catheterization under general anesthesia with at least one set of contemporaneous TDCI and RT-VO2 measurements. RESULTS Thirty-six paired measurements of TDCI and RT-VO2 were made in 27 patients over a 2-year period. Indications for catheterization included congenital diaphragmatic hernia postrepair (n = 13), heart disease post-orthotopic heart transplant (n = 13), and suspected cardiomyopathy (n = 1). Mean age was 21.5 ± 8 months; median weight was 9.9 kg (IQR 8.57, 12.2). RT-VO2 was higher than VO2 predicted by the LaFarge equation (190 ± 31 vs. 173.8 ± 12.8 mL/min/m(2), P < .001), but there was no difference between TDCI and Fick CI calculated using VO2 from any method. Bland-Altman analysis showed excellent agreement between TDCI and Fick CI using RT-VO2 and VO2 predicted by the Lundell equation; Fick CI using VO2 predicted by the LaFarge equation showed fair agreement with TDCI. CONCLUSIONS In children <3 years with a structurally normal heart, RT-VO2 generates highly accurate determinations of Fick CI as compared with TDCI. Additionally, in this population, VO2 derived from the LaFarge and Lundell equations generates accurate Fick CI compared with TDCI. Future studies are needed to identify factors associated with inaccurate VO2 generated from these predictive equations.

Patients with Single Ventricle Anatomy May Respond Better to Octreotide Therapy for Chylothorax After Congenital Heart Surgery

Chylothorax (CTX) occurs in 3% to 6% of children after surgery for congenital heart disease with significant morbidity and mortality. Octreotide has been proposed as therapy, but there are no predictors of response. The objective of this study was to identify possible predictors of response to octreotide.

Pre-operative renal volume predicts peak creatinine after congenital heart surgery in neonates

OBJECTIVE Acute kidney injury is common in neonates following surgery for congenital heart disease. We conducted a retrospective analysis to determine whether neonates with smaller pre-operative renal volume were more likely to develop post-operative acute kidney injury. DESIGN/SETTING We conducted a retrospective review of 72 neonates who underwent congenital heart surgery for any lesion other than patent ductus arteriosus at our institution from January 2007 to December 2011. Renal volume was calculated by ultrasound using the prolate ellipsoid formula. The presence and severity of post-operative acute kidney injury was determined both by measuring the peak serum creatinine in the first 7 days post-operatively and by using the Acute Kidney Injury Network scoring system. RESULTS Using a linear change point model, a threshold renal volume of 17 cm³ was identified. Below this threshold, there was an inverse linear relationship between renal volume and peak post-operative creatinine for all patients (p = 0.036) and the subgroup with a single morphologic right ventricle (p = 0.046). There was a non-significant trend towards more acute kidney injury using Acute Kidney Injury Network criteria in all neonates with renal volume ≤17 cm³ (p = 0.11) and in the subgroup with a single morphologic right ventricle (p = 0.17). CONCLUSIONS Pre-operative renal volume ≤17 cm³ is associated with a higher peak post-operative creatinine and potentially greater risk for post-operative acute kidney injury for neonates undergoing congenital heart surgery. Neonates with a single right ventricle may be at higher risk.

A review of the economics of adult congenital heart disease

Abstract Adults living with congenital heart disease (CHD) now outnumber children with the disease. Thanks to medical advances over the past 75 years, many of these fatal childhood heart problems have changed to chronic medical conditions. As the population of adults with CHD increases, they will require increasingly complex medical, surgical and catheter-based therapies. In addition, social burdens including education, employment and insurability, which increase the societal costs of adult CHD, are now being recognized for adults living with CHD. This review summarizes the available literature on the economics of adult CHD.

Selective pulmonary vasodilation improves ventriculovascular coupling and gas exchange in a patient with unrepaired single-ventricle physiology

We describe a 63-year-old patient with unrepaired tricuspid valve atresia and a hypoplastic right ventricle (single-ventricle physiology) who presented with progressive symptomatic hypoxia. Her anatomy resulted in parallel pulmonary and systemic circulations, pulmonary arterial hypertension, and uncoupling of the ventricle/pulmonary artery. Hemodynamic and coupling data were obtained before and after pulmonary vasoactive treatment, first inhaled nitric oxide and later inhaled treprostinil. The coupling ratio (ratio of ventricular to vascular elastance) shunt fractions and dead space ventilation were calculated before and after treatment. Treatment resulted in improvement of the coupling ratio between the ventricle and the vasculature with optimization of stroke work, equalization of pulmonary and systolic flows, a decrease in dead space ventilation from 75% to 55%, and a significant increase in 6-minute walk distance and improved hypoxia. Inhaled treprostinil significantly increased 6-minute walk distance and improved hypoxia. This is the first report to show that pulmonary vasoactive treatment can be used in a patient with unrepaired single-ventricle anatomy and describes the hemodynamic effects of inhaled therapy on ventriculovascular coupling and gas exchange in the pulmonary circulation in this unique physiology.