Tetralogy of Fallot Repair After Neonatal Right Ventricular Outflow Tract Stenting: Initial Multicenter Experience in Argentina.

Initial management of patients with tetralogy of Fallot, unfavorable anatomy, and reduced pulmonary blood flow is controversial and continues to be a clinical challenge. Pulmonary to systemic shunt anastomosis or primary correction in neonates and small infants is associated with higher morbimortality and increased number of reoperations. Initial right ventricle outflow tract stenting palliation has emerged as an attractive alternative. We report our experience in 14 patients operated on with tetralogy of Fallot and previous right ventricle outflow tract stenting from March 2018 to June 2022. All stented patients had pulmonary annulus and main pulmonary artery Z score ≤ -2.5. Surgical outcomes, complications, and mortality at 30 days were evaluated. Patient's age and weight at surgery were 5.9 months (2-17) and 6.1 kg (3.9-8.9), respectively. Stents were completely removed in 57.1% of patients. A transannular patch was placed in 10 patients, 3 patients required a right ventricle to pulmonary artery conduit due to coronary anomalies and in 1 patient, the pulmonary valve was preserved. Length of stay and ventilation time were 13.6 days (5-27) and 44.8 h (6-44), respectively. Mean time for right ventricle outflow tract stent implantation to surgical correction was 4 months (2-16). There was no mortality, and mean follow-up time of this cohort was 23.1 month (1-41). Surgical correction of severe tetralogy of Fallot after right ventricle outflow tract stenting is an effective alternative achievable without an increase in morbidity and mortality. Difficulty in stent extraction is related to the time since implantation. More number of patients and longer follow-up time are needed to confirm these initial results.

Estrategia híbrida en el manejo de cardiopatías congénitas / Hybrid Strategy in the Management of Congenital Heart Defects

RESUMEN Introducción: El abordaje híbrido implica la colaboración estrecha de los equipos quirúrgico y de hemodinamia para el tratamiento de cardiopatías congénitas complejas, con el objetivo de disminuir el número de intervenciones a través de técnicas menos invasivas y de evitar las limitaciones dadas por el tamaño de los accesos vasculares y la utilización de circulación extracorpórea. Objetivos: Evaluar indicaciones, técnicas, resultados iniciales y seguimiento a corto plazo del abordaje híbrido. Material y métodos: Revisión retrospectiva de pacientes abordados de manera híbrida desde marzo de 2014 hasta septiembre de 2020. Se realizaron 14 procedimientos en 13 pacientes. Edad media de 16,8 meses (1 día-13 años), el 50% fueron neonatos y el 57% de sexo masculino; el peso medio fue 9 kg (1,9-70 kg). Los procedimientos híbridos realizados incluyeron implante de stent en coartación de aorta (4 pacientes), implante de stent ductal (3 pacientes), implante de stent ramas pulmonares (1 paciente), valvuloplastia aórtica neonatal (4 pacientes) y cierre de comunicación interventricular muscular (2 pacientes). El acceso se realizó mediante disección carotídea en 8 procedimientos y esternotomía en los 6 restantes. Resultados: Todos los procedimientos pudieron completarse exitosamente, aunque un paciente presentó fibrilación ventricular posprocedimiento y otro falleció durante el posoperatorio inmediato debido a trastorno grave de la coagulación. El seguimiento de los 12 pacientes restantes fue en promedio de 19 meses y la evolución fue favorable. Conclusiones: Utilizando una estrategia híbrida, los resultados iniciales en términos de sobrevida y mejoramiento de parámetros hemodinámicos fueron adecuados. La selección de casos, el trabajo en equipo y el seguimiento apropiado son cruciales para lograr resultados satisfactorios.

ABSTRACT Background: The hybrid approach implies the close collaboration between surgical and interventional cardiology teams for the treatment of complex congenital heart diseases to reduce the number of interventions by using less invasive techniques, avoid the limitations due to the size of vascular accesses and the use of cardiopulmonary bypass. Objectives: The aim of this study is to evaluate the indications, techniques, initial results and short-term follow-up of the hybrid approach. Methods: We conducted a retrospective analysis of patients treated with hybrid approach between March 2014 and September 2020. Fourteen procedures were performed in 13 patients. Mean age was 16.8 years (1 day-13 years); 50% were neonates, 57% were male and mean weight was 9 kg (1.9-70 kg). The hybrid procedures performed included stenting in coarctation of the aorta (4 patients), ductal stenting (3 patients), stenting of pulmonary artery branches (1 patient), neonatal aortic valvuloplasty (4 patients) and perventricular closure of muscular ventricular septal defect (2 patients). The access used was dissection of the carotid artery in 8 procedures and sternotomy in the remaining 6. Results: All the procedures were successfully completed, except for two patients: one died due to ventricular fibrillation after the procedure, and another in the immediate postoperative period due to severe coagulation abnormality. Mean follow-up of the remaining 12 patients was 19 months with favorable outcome. Conclusions: The initial results with the use of a hybrid strategy were satisfactory in terms of survival and improvement of the hemodynamic parameters. The selection of cases, teamwork and appropriate follow-up are key factors to achieve satisfactory results.

Detection and assignment of inorganic aqueous polymers relevant to environmental nanogeoscience by direct infusion electrospray ionization mass spectrometry.

Inorganic polymers in aqueous solutions are being proposed as essential components in new theories concerning nonclassical nucleation and growth of nanominerals relevant to environmental nanogeosciences. The study of those complex natural processes requires multi-technique analytical approaches able to characterize the solutions and their constituents (solutes, oligomers, polymers, clusters and nanominerals) from atomic to micrometric scales. A novel analytical approach involving an electrospray ionization source (ESI) coupled to time-of-flight mass spectrometry (TOF/MS) was developed to identify inorganic polymers in aqueous solution. To this end, the presence of initial Al oligomers and their polymerization processes was studied during a nanomineral aqueous synthesis (hydrobasaluminte, Al4 SO4 (OH)10 ·12-36H2 O). Ensuring the feasibility and robustness of the methodology as well as the stability of the polymers under study (avoiding undesirable fragmentation), a meticulous study of the ESI-TOF MS working conditions was performed. Precision of the methodology was evaluated obtaining relative standard deviations below 3.3%. For the first time in the study of inorganic polymers in the earth sciences, the mass accuracy error (ppm) has been reported and the use of significant decimal figures of the m/z signal has been taken into account. Complementary to this, a four-step polymer assignment methodology and a database with the Al- and Al-SO4 2- polymers assigned were created. Several polymers have been assigned for the first time, including Al (SO4 )+ ·H2 O, Al2 O(SO4 )2+ ·H2 O, Al5 O4 (OH)5 2+ ·2H2 O, and Al3 O5 (OH)2- ·4H2 O, among others. The results obtained in the present study help create a foundation to include mass spectrometry as a routine analytical technique to study mineral formation in aqueous solution.