Physiological and clinical consequences of relief of right ventricular outflow tract obstruction late after repair of congenital heart defects.

BACKGROUND: Right ventricular outflow tract obstruction (RVOTO) is a common problem after repair of congenital heart disease. Percutaneous pulmonary valve implantation (PPVI) can treat this condition without consequent pulmonary regurgitation or cardiopulmonary bypass. Our aim was to investigate the clinical and physiological response to relieving RVOTO. METHODS AND RESULTS: We studied 18 patients who underwent PPVI for RVOTO (72% male, median age 20 years) from a total of 93 who had this procedure for various indications. All had a right ventricular outflow tract (RVOT) gradient >50 mm Hg on echocardiography without important pulmonary regurgitation (less than mild or regurgitant fraction <10% on magnetic resonance imaging [MRI]). Cardiopulmonary exercise testing, tissue Doppler echocardiography, and MRI were performed before and within 50 days of PPVI. PPVI reduced RVOT gradient (51.4 to 21.7 mm Hg, P<0.001) and right ventricular systolic pressure (72.8 to 47.3 mm Hg, P<0.001) at catheterization. Symptoms and aerobic (25.7 to 28.9 mL.kg(-1).min(-1), P=0.002) and anaerobic (14.4 to 16.2 mL.kg(-1).min(-1), P=0.002) exercise capacity improved. Myocardial systolic velocity improved acutely (tricuspid 4.8 to 5.3 cm/s, P=0.05; mitral 4.7 to 5.5 cm/s, P=0.01), whereas isovolumic acceleration was unchanged. The tricuspid annular velocity was not maintained on intermediate follow-up. Right ventricular end-diastolic volume (99.9 to 89.7 mL/m2, P<0.001) fell, whereas effective stroke volume (43.7 to 48.3 mL/m2, P=0.06) and ejection fraction (48.0% to 56.8%, P=0.01) increased. Left ventricular end-diastolic volume (72.5 to 77.4 mL/m2, P=0.145), stroke volume (45.3 to 50.6 mL/m2, P=0.02), and ejection fraction (62.6% to 65.8%, P=0.03) increased. CONCLUSIONS: PPVI relieves RVOTO, which leads to an early improvement in biventricular performance. Furthermore, it reduces symptoms and improves exercise tolerance. These findings have important implications for the management of this increasingly common condition

Percutaneous pulmonary valve implantation in humans - Results in 59 consecutive patients

Background - Right ventricular outflow tract (RVOT) reconstruction with valved conduits in infancy and childhood leads to reintervention for pulmonary regurgitation and stenosis in later life.Methods and Results - Patients with pulmonary regurgitation with or without stenosis after repair of congenital heart disease had percutaneous pulmonary valve implantation (PPVI). Mortality, hemodynamic improvement, freedom from explantation, and subjective and objective changes in exercise tolerance were end points. PPVI was performed successfully in 58 patients, 32 male, with a median age of 16 years and median weight of 56 kg. The majority had a variant of tetralogy of Fallot (n = 36), or transposition of the great arteries, ventricular septal defect with pulmonary stenosis (n = 8). The right ventricular (RV) pressure (64.4 +/- 17.2 to 50.4 +/- 14 mm Hg, P < 0.001), RVOT gradient (33 +/- 24.6 to 19.5 +/- 15.3, P < 0.001), and pulmonary regurgitation ( PR) (grade 2 of greater before, none greater than grade 2 after, P < 0.001) decreased significantly after PPVI. MRI showed significant reduction in PR fraction (21 +/- 13% versus 3 +/- 4%, P < 0.001) and in RV end-diastolic volume (EDV) (94 +/- 28 versus 82 +/- 24 mL (.) beat(-1) (.) m(-2), P < 0.001) and a significant increase in left ventricular EDV ( 64 +/- 12 versus 71 +/- 13 mL (.) beat(-1.) m(-2), P = 0.005) and effective RV stroke volume ( 37 +/- 7 versus 42 +/- 9 mL (.) beat(-1) (.) m(-2), P = 0.006) in 28 patients (age 19 +/- 8 years). A further 16 subjects, on metabolic exercise testing, showed significant improvement in V(O2)max (26 +/- 7 versus 29 +/- 6 mL (.) kg(-1) (.) min(-1), P < 0.001). There was no mortality.Conclusions - PPVI is feasible at low risk, with quantifiable improvement in MRI-defined ventricular parameters and pulmonary regurgitation, and results in subjective and objective improvement in exercise capacity

Off-pump replacement of the pulmonary valve in large right ventricular outflow tracts: A hybrid approach

BackgroundPercutaneous pulmonary valve replacement has recently been introduced and is under investigation in humans. This technique is, however, limited to patients with a right ventricular outflow tract that does not exceed 22 mm in diameter. We report our experience of off-pump pulmonary valve replacement using a hybrid approach in animals with large right ventricular outflow tracts.MethodsEight ewes were included in the protocol and were equally divided into 2 groups. A left thoracotomy was first performed, and the main pulmonary artery was banded by using 2 radiopaque rings with a diameter of 18 mm that allowed for further pulmonary valve replacement. We then intended to implant a valved stent either percutaneously (group 1) or through a transventricular approach (group 2). All animals were killed after valve implantation. The operation allowed the pulmonary diameter to be reduced from 30 to 17.6 mm.ResultsThe right ventricular pressure did not significantly increase after reduction of the pulmonary artery diameter (25 vs 36 mm Hg). Subsequent pulmonary valve replacement through a percutaneous or a transventricular approach was always possible without any requirement for extracorporeal circulation. All devices were successfully delivered inside the pulmonary artery banding and were functioning perfectly at early evaluation.ConclusionsImplantation of a pulmonary valve is possible in ewes through a hybrid approach when the right ventricular outflow tract exceeds 22 mm in diameter. This involves both surgeons and interventionists and allows for a staged procedure in which the valvulation is performed percutaneously or, for a combined hybrid approach, in which the valve is implanted off pump transventricularly during the same operation

Cardiac outcomes in severe acute respiratory syndrome coronavirus-2-associated multisystem inflammatory syndrome at a tertiary paediatric hospital

INTRODUCTION: We describe a cohort of children referred with multisystem inflammatory syndrome in children associated with severe acute respiratory syndrome coronavirus 2 and compare this cohort with a 2019 cohort of children with Kawasaki disease. METHODS: We conducted a retrospective cohort study of 2019 and 2020 referrals to the inflammatory cardiology service at Great Ormond Street Hospital for Children. We compared cardiac and inflammatory parameters of a sub-section of the 2020 cohort who presented with reduced left ventricular ejection fraction with the remainder of the cohort. RESULTS: Referrals significantly increased between February and June 2020 compared to 2019 (19.8/30 days versus 3.9/30 days). Frequency of coronary artery aneurysms (11/79 (13.9%) versus 7/47 (14.9%)) or severe coronary artery aneurysms (6/79 (7.6%) versus 3/47 (6.4%)) was similar between 2020 and 2019, respectively. The 2020 cohort was older (median age 9.07 years versus 2.38 years), more likely to be of Black, Asian, or other minority ethnic group (60/76 (78.9%) versus 25/42 (59.5%)), and more likely to require inotropic support (22 (27.5%) versus 0 (0%)). Even children with significantly reduced left ventricular ejection fraction demonstrated complete recovery of cardiac function within 10 days (mean 5.25 days ± 2.7). DISCUSSION: We observed complete recovery of myocardial dysfunction and an overall low rate of permanent coronary sequelae, indicating that the majority of children with multisystem inflammatory syndrome in children are unlikely to encounter long-term cardiac morbidity. Although the frequency of myocardial dysfunction and inotropic support requirement is not consistent with a diagnosis of Kawasaki disease, the frequency of coronary artery abnormalities and severe coronary artery abnormalities suggests a degree of phenotypic overlap

Biventricular Response After Pulmonary Valve Replacement for Right Ventricular Outflow Tract Dysfunction

Background— The timing of pulmonary valve replacement (PVR) for free pulmonary incompetence in patients with congenital heart disease remains a dilemma for clinicians. We wanted to assess the determinants of improvement after PVR for pulmonary regurgitation over a wide range of patient ages and to use any identified predictors to compare clinical outcomes between patient groups. Methods and Results— Seventy-one patients (mean age 22±11 years; range, 8.5 to 64.9; 72% tetralogy of Fallot) underwent PVR for severe pulmonary regurgitation. New York Heart Association class improved after PVR (median of 2 to 1, P <0.0001). MRI and cardiopulmonary exercise testing were performed before and 1 year after intervention. After PVR, there was a significant reduction in right ventricular volumes (end diastolic volume 142±43 to 91±18, end systolic volume 73±33 to 43±14 mL/m 2 , P <0.0001), whereas left ventricular end diastolic volume increased (66±12 to 73±13 mL/m 2 , P <0.0001). Effective cardiac output significantly increased (right ventricular: 3.0±0.8 to 3.3±0.8 L/min, P =0.013 and left ventricular: 3.0±0.6 to 3.4±0.7 L/min, P <0.0001). On cardiopulmonary exercise testing, ventilatory response to carbon dioxide production at anaerobic threshold improved from 35.9±5.8 to 34.1±6.2 ( P =0.008). Normalization of ventilatory response to carbon dioxide production was most likely to occur when PVR was performed at an age younger than 17.5 years ( P =0.013). Conclusions— A relatively aggressive PVR policy (end diastolic volume <150 mL/m 2 ) leads to normalization of right ventricular volumes, improvement in biventricular function, and submaximal exercise capacity. Normalization of ventilatory response to carbon dioxide production is most likely to occur when surgery is performed at an age ≤17.5 years. This is also associated with a better left ventricular filling and systolic function after surgery

Piloting the Use of Patient-Specific Cardiac Models as a Novel Tool to Facilitate Communication During Cinical Consultations

This pilot study aimed to assess the impact of using patient-specific three-dimensional (3D) models of congenital heart disease (CHD) during consultations with adolescent patients. Adolescent CHD patients (n = 20, age 15-18 years, 15 male) were asked to complete two questionnaires during a cardiology transition clinic at a specialist centre. The first questionnaire was completed just before routine consultation with the cardiologist, the second just after the consultation. During the consultation, each patient was presented with a 3D full heart model realised from their medical imaging data. The model was used by the cardiologist to point to main features of the CHD. Outcome measures included rating of health status, confidence in explaining their condition to others, name and features of their CHD (as a surrogate for CHD knowledge), impact of CHD on their lifestyle, satisfaction with previous/current visits, positive/negative features of the 3D model, and open-ended feedback. Significant improvements were registered in confidence in explaining their condition to others (p = 0.008), knowledge of CHD (p < 0.001) and patients' satisfaction (p = 0.005). Descriptions of CHD and impact on lifestyle were more eloquent after seeing a 3D model. The majority of participants reported that models helped their understanding and improved their visit, with a non-negligible 30% of participants indicating that the model made them feel more anxious about their condition. Content analysis of open-ended feedback revealed an overall positive attitude of the participants toward 3D models. Clinical translation of 3D models of CHD for communication purposes warrants further exploration in larger studies

Can finite element models of ballooning procedures yield mechanical response of the cardiovascular site to overexpansion?

Patient-specific numerical models could aid the decision-making process for percutaneous valve selection; in order to be fully informative, they should include patient-specific data of both anatomy and mechanics of the implantation site. This information can be derived from routine clinical imaging during the cardiac cycle, but data on the implantation site mechanical response to device expansion are not routinely available. We aim to derive the implantation site response to overexpansion by monitoring pressure/dimensional changes during balloon sizing procedures and by applying a reverse engineering approach using a validated computational balloon model. This study presents the proof of concept for such computational framework tested in-vitro. A finite element (FE) model of a PTS-X405 sizing balloon (NuMed, Inc., USA) was created and validated against bench tests carried out on an ad hoc experimental apparatus: first on the balloon alone to replicate free expansion; second on the inflation of the balloon in a rapid prototyped cylinder with material deemed suitable for replicating pulmonary arteries in order to validate balloon/implantation site interaction algorithm. Finally, the balloon was inflated inside a compliant rapid prototyped patient-specific right ventricular outflow tract to test the validity of the approach. The corresponding FE simulation was set up to iteratively infer the mechanical response of the anatomical model. The test in this simplified condition confirmed the feasibility of the proposed approach and the potential for this methodology to provide patient-specific information on mechanical response of the implantation site when overexpanded, ultimately for more realistic computational simulations in patient-specific settings