The impact of unilateral pulmonary artery stenosis on right ventricular to pulmonary arterial coupling in patients with transposition of the great arteries.

BACKGROUND: Unilateral pulmonary artery (PA) stenosis is common in the transposition of the great arteries (TGA) after arterial switch operation (ASO) but the effects on the right ventricle (RV) remain unclear. AIMS: To assess the effects of unilateral PA stenosis on RV afterload and function in pediatric patients with TGA-ASO. METHODS: In this retrospective study, eight TGA patients with unilateral PA stenosis underwent heart catheterization and cardiac magnetic resonance (CMR) imaging. RV pressures, RV afterload (arterial elastance [Ea]), PA compliance, RV contractility (end-systolic elastance [Ees]), RV-to-PA (RV-PA) coupling (Ees/Ea), and RV diastolic stiffness (end-diastolic elastance [Eed]) were analyzed and compared to normal values from the literature. RESULTS: In all TGA patients (mean age 12 ± 3 years), RV afterload (Ea) and RV pressures were increased whereas PA compliance was reduced. RV contractility (Ees) was decreased resulting in RV-PA uncoupling. RV diastolic stiffness (Eed) was increased. CMR-derived RV volumes, mass, and ejection fraction were preserved. CONCLUSION: Unilateral PA stenosis results in an increased RV afterload in TGA patients after ASO. RV remodeling and function remain within normal limits when analyzed by CMR but RV pressure-volume loop analysis shows impaired RV diastolic stiffness and RV contractility leading to RV-PA uncoupling.

Chronic inflammatory pulmonary artery lesion causing right pulmonary artery stenosis 15 years post Blalock-Taussig shunt ligation.

Discrete central endovascular pulmonary arterial lesions raise clinical concern for malignancy such as primary pulmonary artery sarcoma. We present a case of a female in her late teens who had an obstructive mid right pulmonary artery lesion found on follow-up imaging 15 years after Tetralogy of Fallot repair. The lesion was in the vicinity of a previously ligated Blalock-Taussig shunt and causing right PA stenosis with delayed perfusion to the right lung, and a flow-related distal left PA aneurysm. The lesion was excised and confirmed histologically to be inflammatory in nature. Intraoperative microbiology demonstrated growth of the Kytococcus species, and she was managed with 6 weeks of intravenous antibiotics, with a full recovery.

Comparison of long-term survival after endovascular treatment versus medical therapy in patients with Takayasu's arteritis and pulmonary artery stenosis.

OBJECTIVES: There is currently no unanimous consensus on the treatment of Takayasu's arteritis (TAK) involving the pulmonary artery, and there are very few related studies that compare the efficacies of drug-based therapy and revascularization. This study aimed to compare the long-term survival outcomes after endovascular treatment and medical therapy in TAK patients with pulmonary artery stenosis (PAS) and pulmonary hypertension (PH). METHODS: A total of 129 TAK patients with PAS and PH (women, 101; men, 28; mean age, 40.5 years) were retrospectively enrolled in this study. Data on clinical features, treatment regimens, and mortality, were collected. Patients were categorised into medical treatment (n=75) and percutaneous transluminal pulmonary angioplasty (PTPA; n=54: 52 with PTPA and 2 with stent implantation) groups. The primary endpoint was cardiac mortality. The median follow-up time was 54 (40.5, 58.5) months. RESULTS: There were no significant differences in sex, age, comorbidities, disease activity, World Health Organization (WHO) function classification, and 6-min walk distance (6MWD) between the two groups at baseline. Compared with the conservative treatment group, cardiac mortality, WHO functional class, and 6MWD were significantly improved in the PTPA group (p=0.031, p<0.001, and p=0.004, respectively). CONCLUSIONS: Under basic medicine, PTPA therapy improves the long-term survival of TAK patients with PAS and PH compared to medical treatment alone. PTPA may be a promising modality for the TAK patients with PAS and PH.

Long-Term Outcomes After Percutaneous Transluminal Pulmonary Angioplasty in Patients With Takayasu Arteritis and Pulmonary Hypertension.

Objective: To investigate the long-term efficacy of percutaneous transluminal pulmonary angioplasty (PTPA) in patients with Takayasu arteritis (TA) and pulmonary artery stenosis and pulmonary hypertension (PH). Methods: Data from 183 lesions from 79 surgeries performed on 32 patients with TA and PH were analyzed. Symptoms, laboratory investigation results, World Health Organization (WHO) functional class, 6-min walk distance (6 MWD), hemodynamic parameters, and prognosis were analyzed at baseline and follow-up. Results: The mean (± SD) age of the 32 patients (28 female, 4 male) was 42.8 ± 11.9 years, and the median follow-up was 49.5 months (interquartile range, 26-71 months). Compared with baseline, changes in total bilirubin, N-terminal pro-brain natriuretic peptide (NT-proBNP) level, 6 MWD, and WHO score functional class demonstrated significant differences (P<0.001). Echocardiography findings, right and left ventricular diameter, tricuspid annular plane systolic excursion, and estimated pulmonary artery systolic pressure were all improved (P=0.016, P<0.001, P<0.001, and P=0.005, respectively). Importantly, repeat right heart catheterization revealed that mean pulmonary artery pressure, pulmonary vascular resistance, and cardiac index also improved significantly at follow-up (P<0.001, P<0.001, and P=0.011, respectively). Pulmonary angiography revealed post-procedure restenosis in 64 (35.0%) lesions underwent PTPA within three to six months. Among three patients who underwent stent implantation, one experienced restenosis. Two patients died during the follow-up period, one from aggravation of right heart failure after lung infection, and the other in a traffic accident. Conclusions: Results of this study indicated that PTPA significantly improved clinical symptoms, exercise tolerance, and hemodynamic parameters in patients with TA pulmonary artery stenosis and PH. More importantly, reperfusion pulmonary edema significantly decreased, and no patient died of PTPA-related complications with guidance from the pressure wire.

Virtual Transcatheter Interventions for Peripheral Pulmonary Artery Stenosis in Williams and Alagille Syndromes.

Background Despite favorable outcomes of surgical pulmonary artery (PA) reconstruction, isolated proximal stenting of the central PAs is common clinical practice for patients with peripheral PA stenosis in association with Williams and Alagille syndromes. Given the technical challenges of PA reconstruction and the morbidities associated with transcatheter interventions, the hemodynamic consequences of all treatment strategies must be rigorously assessed. Our study aims to model, assess, and predict hemodynamic outcomes of transcatheter interventions in these patients. Methods and Results Isolated proximal and "extensive" interventions (stenting and/or balloon angioplasty of proximal and lobar vessels) were performed in silico on 6 patient-specific PA models. Autoregulatory adaptation of the cardiac output and downstream arterial resistance was modeled in response to intervention-induced hemodynamic perturbations. Postintervention computational fluid dynamics predictions were validated in 2 stented patients and quantitatively assessed in 4 surgical patients. Our computational methods accurately predicted postinterventional PA pressures, the primary indicators of success for treatment of peripheral PA stenosis. Proximal and extensive treatment achieved median reductions of 14% and 40% in main PA systolic pressure, 27% and 56% in pulmonary vascular resistance, and 10% and 45% in right ventricular stroke work, respectively. Conclusions In patients with Williams and Alagille syndromes, extensive transcatheter intervention is required to sufficiently reduce PA pressures and right ventricular stroke work. Transcatheter therapy was shown to be ineffective for long-segment stenosis and pales hemodynamically in comparison with published outcomes of surgical reconstruction. Regardless of the chosen strategy, a virtual treatment planning platform could identify lesions most critical for optimizing right ventricular afterload.

Echocardiographic Predictors of Ductal Tissue-Related Branch Pulmonary Artery Stenosis in Pulmonary Atresia.

Branch pulmonary artery (PA) stenosis due to ductus arteriosus (DA) tissue (DA-PS) contributes to the morbidity associated with pulmonary atresia (PAtr). We sought to identify preoperative echocardiographic features predictive of DA-PS. Patients consecutively encountered with PAtr and a DA-dependent pulmonary circulation at birth who underwent intervention in our program over a 5-year period were identified and records reviewed. Preoperative echocardiograms were reviewed to identify features that predicted postoperative DA-PS. Seventy patients with PAtr met inclusion criteria and 36 (51%) had DA-PS. At preoperative echocardiography, the proximal diameter of the PA ipsilateral to the DA was smaller in those with versus without DA-PS (Z-score - 4.8 ± 1.7 vs - 1.1 ± 1.7, respectively p < 0.001). PA origins could not be imaged on the same axial plane in 21/36 (58%) with versus 2/34 (6%) without DA-PS. Patients with DA-PS had an obtuse posterior angle of the PA bifurcation compared to those without (128 ± 17° and 87 ± 21°, p < 0.001), and a posterior angle of > 100° best predicted DA-PS with a sensitivity of 97% and specificity of 76%. An abnormal PA relationship and/or an obtuse posterior bifurcation angle had a sensitivity, specificity, positive and negative predictive value for DA-PS of 78%, 94%, 90% and 86%, respectively. Finally, DA insertion was into the ipsilateral PA in 26/36 (72%) of cases with DA-PS. A smaller proximal ipsilateral PA diameter, inability to image the PAs in the same plane, a posterior PA bifurcation angle of > 100°, and insertion of the DA in the ipsilateral PA demonstrated by echo are useful in identifying patients at risk for DA-PS.

Cutting balloon angioplasty on branch pulmonary artery stenosis in pediatric patients.

OBJECTIVES: To identify medium-term results following cutting balloon angioplasty (CBA) for branch pulmonary artery stenosis (PAS) and predictors of successful intervention. BACKGROUND: CBA has emerged as a successful alternative therapy for PAS resistant to conventional balloon angioplasty techniques but there is little information on medium and long-term outcomes. METHODS: This is a descriptive, single center, retrospective chart review of pediatric patients who underwent CBA for PAS at Arkansas Children's Hospital between May 2005 and December 2020. We reviewed demographics, procedural specifics, and 30-day complications. RESULTS: Forty-four patients underwent pulmonary artery CBA on 114 pulmonary artery segments through 126 catheterization cases, totaling 148 CBA events. Thirty-three individual pulmonary arteries underwent repeat intervention. Average minimal luminal diameter increase from pre-CBA to end of follow-up was 57% (CI, 38%-75%). Absence of Tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries (TOF/PA/MAPCAs) and the absence of Alagille Syndrome, Williams Syndrome, or Arterial Tortuosity Syndrome (ATS) were associated with increased odds of sustained success by 70% (CI, 0.11-0.79) and 91% (CI, 0.02-0.56), respectively. Increasing the cutting balloon diameter-to-minimal luminal diameter ratio by 0.5 increased odds of successful intervention by 2.37-fold (CI, 1.7-3.3). Seven patients had 30-day complications including one death. CONCLUSIONS: In the longest follow-up to date of children and adolescents who underwent CBA for branch PAS, we found that there was moderate medium-term success. Additionally, absence of TOF/PA/MAPCAs, absence of Alagille Syndrome, Williams Syndrome, or ATS, and high cutting balloon diameter-to-minimal luminal diameter ratio are predictors of sustained results.

Balloon Angioplasty for Pulmonary Artery Stenosis After Complete Unifocalization and Repair of Tetralogy of Fallot With Major Aortopulmonary Collaterals.

OBJECTIVES: The objective of this study was to assess procedural outcomes of balloon pulmonary artery (PA) angioplasty procedures after complete repair of tetralogy of Fallot with major aortopulmonary collateral arteries (TOF/MAPCAs). BACKGROUND: Our approach to patients with TOF/MAPCAs emphasizes early complete unifocalization and repair. Major PA reinterventions are relatively uncommon. Balloon PA angioplasty is often used, but the effectiveness of balloon PA angioplasty in this population is unknown. METHODS: The study cohort comprised patients who underwent complete unifocalization and repair of TOF/ MAPCAs at our center between 2002-2018 and underwent balloon PA angioplasty after repair. To assess immediate procedural outcomes, pre- and postintervention PA measurements were compared. RESULTS: We reviewed 134 vessels that were dilated a median of 1.1 years after repair in 60 patients (median 2 PA branches per patient). Treated vessels included 15 central, 64 lobar, and 55 segmental branches. The median PA diameter at the level of stenosis increased from 1.9 mm to 3.3 mm (P<.001), and the median diameter increase was 50%. All but 6 treated vessels were enlarged. The stenosis-distal diameter ratio increased from a median of 64% to 89% (P<.001). The median central PA to aortic systolic pressure ratio was 47% before and 39% after intervention (P<.001). CONCLUSIONS: Balloon PA angioplasty was acutely effective at treating most stenoses of reconstructed PA branches after repair of TOF/MAPCAs. Simple angioplasty can be a useful tool in treating isolated or modest stenoses after unifocalization/PA reconstruction surgery using our approach.

Autologous skeletal myoblast patch implantation prevents the deterioration of myocardial ischemia and right heart dysfunction in a pressure-overloaded right heart porcine model.

Right ventricular dysfunction is a predictor for worse outcomes in patients with congenital heart disease. Myocardial ischemia is primarily associated with right ventricular dysfunction in patients with congenital heart disease and may be a therapeutic target for right ventricular dysfunction. Previously, autologous skeletal myoblast patch therapy showed an angiogenic effect for left ventricular dysfunction through cytokine paracrine effects; however, its efficacy in right ventricular dysfunction has not been evaluated. Thus, this study aimed to evaluate the angiogenic effect of autologous skeletal myoblast patch therapy and amelioration of metabolic and functional dysfunction, in a pressure-overloaded right heart porcine model. Pulmonary artery stenosis was induced by a vascular occluder in minipigs; after two months, autologous skeletal myoblast patch implantation on the right ventricular free wall was performed (n = 6). The control minipigs underwent a sham operation (n = 6). The autologous skeletal myoblast patch therapy alleviated right ventricular dilatation and ameliorated right ventricular systolic and diastolic dysfunction. 11C-acetate kinetic analysis using positron emission tomography showed improvement in myocardial oxidative metabolism and myocardial flow reserve after cell patch implantation. On histopathology, a higher capillary density and vascular maturity with reduction of myocardial ischemia were observed after patch implantation. Furthermore, analysis of mRNA expression revealed that the angiogenic markers were upregulated, and ischemic markers were downregulated after patch implantation. Thus, autologous skeletal myoblast patch therapy ameliorated metabolic and functional dysfunction in a pressure-overloaded right heart porcine model, by alleviating myocardial ischemia through angiogenesis.

Fate of the Left Pulmonary Artery and Thoracic Aorta After Transcatheter Patent Ductus Arteriosus Closure in Low Birth Weight Premature Infants.

Transcatheter patent ductus arteriosus closure (TCPC) is an emerging treatment for low birth weight extremely premature neonates (EPNs). Left pulmonary artery (LPA) and descending aorta (DAO) obstruction are described device-related complications, however, data on mid- and long-term vascular outcomes are lacking. A retrospective analysis of EPNs who underwent successful TCPC at our institution from 03/2013 to 12/2018 was performed. Two-dimensional echocardiography and spectral Doppler velocities from various time points before and after TCPC were used to identify LPA and DAO flow disturbances. A total of 44 EPNs underwent successful TCPC at a median (range) procedural weight of 1150 g (755-2500 g). Thirty-two (73%) patients were closed with the AVP II and 12 (27%) with the Amplatzer Piccolo device. LPA and DAO velocities on average remained within normal limits and improved spontaneously in long-term follow up (26.1 months, range 1-75 months). One patient, who had concerning LPA flow characteristics immediately after device implant (peak velocity 2.6 m/s) developed progressive LPA stenosis requiring stent placement 3 months post-procedure. In the remaining infants, including 7 (16%) who developed LPA and 3 (7%) who developed DAO flow disturbances (range 2-2.4 m/s), all had progressive normalization of flow velocities over time. TCPC can be performed safely in EPNs with a low incidence of LPA and DAO obstruction. In the absence of significant progressive vascular obstruction in the early post-procedure period, mild increases in LPA and DAO flow velocities tend to improve spontaneously and normalize in long-term follow-up.

Progression in Fontan conduit stenosis and hemodynamic impact during childhood and adolescence.

OBJECTIVE: To characterize changes in Fontan conduit size over time and determine if cross-sectional area (CSA) affects cardiac output, pulmonary artery growth, and exercise capacity. METHODS: We conducted a retrospective cross-sectional study of patients with Fontan physiology who underwent cardiac magnetic resonance imaging or cardiac catheterization between January 2013 and October 2019. We collected Fontan and pulmonary artery measurements, hemodynamic data, and cardiopulmonary exercise test data. We identified 158 patients with an extracardiac Fontan. We measured minimum and mean Fontan conduit CSA and assessed whether these correlated with Nakata index, cardiac index, or exercise capacity. RESULTS: Minimum Fontan CSA decreased by a median of 33% (24%, 40%) during a mean follow-up of 9.6 years. Median percentage decrease in Fontan CSA did not differ among 16-, 18-, and 20-mm conduits (P = .29). There was a significant decrease in the minimum Fontan CSA (33% [25%, 41%]) starting less than 1-year post-Fontan. Median Nakata index was 177.6 mm2/m2 (149.1, 210.8) and was not associated with Fontan CSA/BSA (ρ = 0.09, P = .29). Fontan CSA/BSA was not associated with cardiac index (ρ = -0.003, P = .97). A larger Fontan CSA/BSA had a modest correlation with % predicted oxygen consumption (ρ = 0.31, P = .013). CONCLUSIONS: Fontan conduit CSA decreases as early as 6 months post-Fontan. The minimum Fontan CSA/BSA was not associated with cardiac index or pulmonary artery size but did correlate with % predicted peak oxygen consumption.

Echocardiography and MRI parameters associated with exercise capacity in patients after the arterial switch operation.

BACKGROUND: The arterial switch operation (ASO) for transposition of the great arteries has excellent survival, but a substantial number of patients suffer from a reduced exercise capacity. The goal of this study was to identify imaging parameters associated with a reduced exercise capacity in patients after ASO. METHODS: A retrospective analysis was performed of ASO patients who underwent cardiopulmonary exercise testing (CPET) between 2007 and 2017. Reduced exercise performance was defined as a reduced workload peak (Wpeak) with Z-score <-2 or a peak oxygen uptake indexed for weight (VO2peak/kg) with Z-score <-2. Data on echocardiography and cardiac magnetic resonance performed within 1 year of the CPET were collected for comparison. RESULTS: A total of 81 ASO patients (age 17±7 years) were included. Reduced exercise performance was found in 22 patients (27%) as expressed by either a reduced Wpeak and/or a reduced VO2peak/kg. Main pulmonary artery gradient and tricuspid regurgitation gradient by echocardiography were found to be associated with reduced Wpeak (p=0.031; p=0.020, respectively). The main pulmonary artery gradient and tricuspid regurgitation gradient by echocardiography were found to be associated with reduced VO2peak/kg (p=0.009; p=0.019, respectively). No left ventricular parameters were found to be associated with abnormal exercise performance. CONCLUSION: This study demonstrates that ASO patients frequently experience reduced exercise capacity. Echocardiographic evidence of main pulmonary artery stenosis and increased right ventricular pressure were associated with reduced exercise capacity, and are therefore key to monitor during serial follow-up of ASO patients.