Bryan H. Goldstein

Relation of Systemic Venous Return, Pulmonary Vascular Resistance, and Diastolic Dysfunction to Exercise Capacity in Patients With Single Ventricle Receiving Fontan Palliation

Fontan patients have a reduced exercise capacity, primarily owing to limitations in the ability to augment pulmonary blood flow and stroke volume. To date, the mechanism of peak exercise pulmonary blood flow restriction has not been elucidated. We performed a single-center, prospective, crossover trial of supine and upright exercise in Fontan patients and healthy controls to determine the mechanisms of exercise limitation in the Fontan-palliated patient. A total of 29 Fontan patients and 16 control subjects completed the protocol. The duration of exercise, percentage of predicted peak oxygen consumption (VO(2)) and peak work were reduced in the Fontan group, regardless of posture (p < or = 0.03). The percentage of predicted oxygen pulse, a surrogate for pulmonary stroke volume, was not increased with supine posture in the Fontan cohort (upright, 82.3 + or - 18.8% vs supine, 82.4 + or - 19.7%; p = 0.6). In both groups, the percentage of predicted peak VO(2) was lower with supine exercise than with upright exercise (p < or =0.002). Diastolic dysfunction was present in 57% of the Fontan patients and was associated with a reduced percentage of predicted peak VO(2) (p = 0.04) and supine peak work (p = 0.008). Six Fontan patients who underwent supine exercise with indwelling catheters failed to demonstrate the expected decrease in pulmonary vascular resistance characteristically seen with peak exercise (at rest, 2.8 + or - 0.7 mm Hg/L/min/m(2) vs at peak, 2.8 + or - 0.9 mm Hg/L/min/m(2); p = 0.9). In conclusion, supine exercise in Fontan patients does not result in an increased VO(2) or oxygen pulse, suggesting that inadequate venous return might not be the primary limitation of exercise capacity in this population. Diastolic dysfunction and relatively excessive peak exercise pulmonary vascular resistance might be more important factors in Fontan exercise limitation.

Transcatheter Tricuspid Valve-in-Valve Implantation for the Treatment of Dysfunctional Surgical Bioprosthetic Valves: An International, Multicenter Registry Study.

Background— Off-label use of transcatheter aortic and pulmonary valve prostheses for tricuspid valve-in-valve implantation (TVIV) within dysfunctional surgical tricuspid valve (TV) bioprostheses has been described in small reports. Methods and Results— An international, multicenter registry was developed to collect data on TVIV cases. Patient-related factors, procedural details and outcomes, and follow-up data were analyzed. Valve-in-ring or heterotopic TV implantation procedures were not included. Data were collected on 156 patients with bioprosthetic TV dysfunction who underwent catheterization with planned TVIV. The median age was 40 years, and 71% of patients were in New York Heart Association class III or IV. Among 152 patients in whom TVIV was attempted with a Melody (n=94) or Sapien (n=58) valve, implantation was successful in 150, with few serious complications. After TVIV, both the TV inflow gradient and tricuspid regurgitation grade improved significantly. During follow-up (median, 13.3 months), 22 patients died, 5 within 30 days; all 22 patients were in New York Heart Association class III or IV, and 9 were hospitalized before TVIV. There were 10 TV reinterventions, and 3 other patients had significant recurrent TV dysfunction. At follow-up, 77% of patients were in New York Heart Association class I or II (P<0.001 versus before TVIV). Outcomes did not differ according to surgical valve size or TVIV valve type. Conclusions— TVIV with commercially available transcatheter prostheses is technically and clinically successful in patients of various ages across a wide range of valve size. Although preimplantation clinical status was associated with outcome, many patients in New York Heart Association class III or IV at baseline improved. TVIV should be considered a viable option for treatment of failing TV bioprostheses.

Percutaneous Balloon-Expandable Covered Stent Implantation for Treatment of Traumatic Aortic Injury in Children and Adolescents

Surgical treatment of pediatric acute traumatic aortic injury (TAI) after blunt chest trauma is standard of care. Use of endovascular stent grafts for treatment of TAI in adults is common but has important limitations in children. We sought to describe the use of balloon-expandable covered endovascular stents for treatment of TAI in children and adolescents. Participants of the multicenter Coarctation of the Aorta Stent Trial (COAST) had access to investigational large-diameter, balloon-expandable, covered stents (covered Cheatham-platinum stents; NuMed, Inc., Hopkinton, New York) on an emergency-use basis. From 2008 through 2011, 6 covered stents were implanted in 4 patients at 3 COAST centers for treatment of TAI. Median patient age was 13.5 years (range 11 to 14) and weight was 58 kg (40 to 130). All patients sustained severe extracardiac injuries that were judged to preclude safe open surgical repair of TAI. Median aortic isthmus and stent implantation balloon diameters were 16.4 mm (13.2 to 19) and 19 mm (16 to 20), respectively. Stent implantation was technically successful in all attempts. Complete exclusion of aortic wall injury was achieved in all cases. There were no access site complications. At a median follow-up of 24 months, there was 1 early death (related to underlying head trauma) and 1 patient with recurrent aortic aneurysm who required additional stent implantation. In conclusion, balloon-expandable covered-stent implantation for treatment of pediatric TAI after blunt trauma is generally safe and effective. Availability of this equipment may alter the standard approach to treatment of pediatric TAI.

Usefulness of peripheral vascular function to predict functional health status in patients with Fontan circulation.

After the Fontan operation, patients are at a substantial risk of the development of impaired functional health status. Few early markers of suboptimal outcomes have been identified. We sought to assess the association between peripheral vascular function and functional health status in Fontan-palliated patients. Asymptomatic Fontan patients (n = 51) and age- and gender-matched healthy controls (n = 22) underwent endothelial pulse amplitude testing using a noninvasive fingertip peripheral arterial tonometry (PAT) device. Raw data were transformed into the PAT ratio, an established marker of vascular function. Cardiopulmonary exercise testing was performed using the Bruce protocol. In the Fontan cohort, 94% of patients were New York Heart Association functional class I and 88% had a B-type natriuretic peptide level of <50 pg/ml. The baseline pulse amplitude, a measure that reflects the arterial tone at rest, was greater in the Fontan patients than in the controls (median 2.74, interquartile range 1.96 to 4.13 vs median 1.86, interquartile range 1.14 to 2.79, p = 0.03). The PAT ratio, a measure of reactive hyperemia, was lower in Fontan patients (median 0.17, interquartile range -0.04 to 0.44, vs median 0.50, interquartile range 0.27 to 0.74, p = 0.002). The key parameters of exercise performance, including peak oxygen consumption (median 28.8 ml/kg/min, interquartile range 25.6 to 33.2 vs median 45.5 ml/kg/min, interquartile range 41.7 to 49.9, p <0.0001) and peak work (median 192 W, interquartile range 150 to 246 vs median 330, interquartile range 209 to 402 W, p <0.0001), were lower in Fontan patients than in the controls. The PAT ratio correlated with the peak oxygen consumption (r = 0.28, p = 0.02) and peak work (r = 0.26, p = 0.03). In conclusion, in an asymptomatic Fontan population, there is evidence of reduced basal peripheral arterial tone and vasodilator response, suggesting dysfunction of the endothelium-derived nitric oxide pathway. Vasodilator function appears to correlate with exercise performance.

Hybrid approach for pulmonary atresia with intact ventricular septum: Early single center results and comparison to the standard surgical approach

To examine acute and mid‐term patient outcomes following the hybrid approach to pulmonary atresia with intact ventricular septum (PA‐IVS) compared with the standard surgical approach.

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.

Practice Variation in Single-Ventricle Patients Undergoing Elective Cardiac Catheterization: A Report from the Congenital Cardiac Catheterization Project on Outcomes (C3PO).

OBJECTIVE The objective of this study was to investigate variation in practice surrounding elective cardiac catheterization in patients with single-ventricle (SV) congenital heart disease. DESIGN Patient and procedural characteristics and outcomes during SV catheterization were collected prospectively from eight centers using a web-based registry (Congenital Cardiac Catheterization Project on Outcomes). We attempted to identify a population of elective procedures by limiting the cohort in case type and timing. Cases were then stratified by stage of SV palliation (pre-bidirectional cavopulmonary anastomosis [pre-BCPA], pre-Fontan and post-Fontan) and limited by age. Subcohort analysis was performed by mode of airway management (assisted vs. spontaneous ventilation). Institutional variation was assessed. RESULTS Between 2/2007 and 6/2010, 1459 (10.1%) of 14 467 cases in the registry met the inclusion and exclusion criteria, including 326 pre-BCPA, 571 pre-Fontan and 562 post-Fontan procedures. Median patient age was 0.4 (interquartile range 0.3, 0.5), 2.6 (1.0, 3.4) and 9.6 (5.2, 15.4) years and weight was 5.6 (4.8, 6.4), 12.2 (10.5, 14), and 26.3 (16.6, 51.8) kg in the pre-BCPA, pre-Fontan and post-Fontan cohorts, respectively. Cases were more commonly diagnostic in the pre-BCPA cohort (57%) whereas they were more commonly interventional in the pre-Fontan (69%) and post-Fontan (77%) cohorts. At least one adverse event (AE) occurred in 210 cases (14.4%) overall, including 20% of pre-BCPA, 11% of pre-Fontan and 14% of post-Fontan catheterizations. Mode of airway management was associated with statistically significant, but clinically small differences in hemodynamic measures in the pre- and post-Fontan cohorts, but not in the pre-BCPA group. Considerable practice variation exists across centers with variability in airway management, AE rate, case type, interventions performed and fluoroscopy time, in all SV cohorts. CONCLUSIONS Elective catheterization in SV patients, frequently performed with intervention, is common among US congenital cardiac centers. However, important variation in practice exists during these procedures in SV patients, at all stages of palliation.

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.

Use of a Pressure Guidewire to Assess Pulmonary Artery Band Adequacy in the Hybrid Stage I Procedure for High‐risk Neonates with Hypoplastic Left Heart Syndrome and Variants

OBJECTIVE The hybrid stage I procedure is an alternative palliative strategy for patients with hypoplastic left heart syndrome who traditionally have undergone the Norwood operation. At our institution, the hybrid stage I procedure is employed only for patients with high operative risk. Our objective was to describe our use of a pressure guidewire during the hybrid stage I procedure to assess quantitatively pulmonary artery band adequacy. DESIGN After reviewing the charts on all high-risk patients who underwent a hybrid stage I procedure at our institution, we compared two groups of patients: those who underwent the standard hybrid stage I palliation (standard cohort) and those with pressure wire-facilitated assessment of distal branch pulmonary artery pressure (pressure wire cohort) to evaluate the impact of pressure guidewire use on procedural risk, radiation time, patient outcomes, and need for reoperation for pulmonary artery band adjustment. RESULTS The pressure guidewire was used in 8 of 14 patients at the time of hybrid stage I procedure and was successful and without complication in all attempts. In the standard cohort, 67% of patients needed reoperation for pulmonary artery band adjustment, compared to 12.5% of patients in the pressure wire cohort (P =.09). Procedure time, radiation exposure, and survival to hospital discharge were not different between groups. CONCLUSIONS This novel use of a pressure guidewire to assess quantitatively pulmonary artery band adequacy at the time of placement is feasible, safe and may decrease the need for reoperation for pulmonary artery band adjustment.

Factors affecting Fontan length of stay: Results from the Single Ventricle Reconstruction trial

BACKGROUND In the Single Ventricle Reconstruction trial, infants with hypoplastic left heart syndrome (HLHS) who received a right-ventricle-to-pulmonary-artery shunt (RVPAS) versus a modified Blalock-Taussig shunt (MBTS) had lower early postoperative mortality, but more complications at 14 months. We explored the effect of shunt type and other patient, medical, and surgical factors on postoperative length of stay (LOS) after the Fontan operation. METHODS Fontan postoperative course was ascertained from medical record review. Cox proportional hazards modeling was used to identify factors associated with LOS. RESULTS Of 327 subjects who underwent Fontan, 323 were analyzed (1 death, 1 biventricular repair, 2 with missing data). Median age and weight at Fontan were 2.8 years (interquartile range [IQR]: 2.3, 3.4) and 12.7 kg (IQR: 11.4, 14.1), respectively. Fontan type was extracardiac in 55% and lateral tunnel in 45%; 87% were fenestrated. The RVPAS and MBTS subjects had similar LOS (median 11 days [IQR: 9, 18] vs 10 days [IQR: 9, 13]; P = .23). Independent risk factors for longer LOS were treatment center (P < .01), LOS at stage II (hazard ratio [HR] 1.02 for each additional day; P < .01), and pre-Fontan complications (HR 1.03 for each additional complication; P = .04). Use of deep hypothermic circulatory arrest at Fontan (HR 0.64; P = .02) was independently associated with shorter LOS. When center was excluded from the model, pre-Fontan complications and use of circulatory arrest were no longer significant; instead, older age at stage II (HR 1.08 for each additional month; P = .01) predicted longer LOS. In 254 subjects who had a pre-Fontan echocardiogram, at least moderate tricuspid regurgitation was independently associated with longer LOS, both with center (HR 1.72; P < .01) and without center in the model (HR 1.49; P = .02). CONCLUSIONS In this multicenter prospective cohort of subjects with HLHS, Norwood shunt type was not associated with Fontan LOS. Rather, global measures of earlier medical complexity indicate greater likelihood of longer LOS after the Fontan operation.