Asymptomatic right ventricular dysfunction in surgically repaired adult tetralogy of fallot patients

Concomitant pulmonary valve replacement with intracardiac repair for adult tetralogy of Fallot

Objectives :

Adult patients undergoing tetralogy of Fallot (TOF) repair have a higher risk of mortality compared to pediatric patients. Pulmonary regurgitation (PR) further predisposes these patients to heart failure, arrhythmias, and sudden death. Pulmonary valve replacement (PVR) may improve the symptoms in these patients but, fails to reverse the other deleterious effects. Aim of our study was to evaluate the effect of concomitant PVR with TOF repair on right ventricular (RV) parameters, cardiopulmonary exercise capacity, and bioprosthetic valve durability at mid-term.

Materials and Methods:

Between January 2013 and August 2018, 37 adolescents and adults with TOF who had hypoplastic pulmonary annulus underwent concomitant TOF repair with PVR at our institute. We retrospectively collected the data from the hospital records including follow-up.

Results :

Mean age of the patients was 18.48 ± 7.53 years. Bioprosthetic valve size ranged from 19 mm to 25 mm. There was no early or late mortality. No patient had developed significant perioperative complications. At a mean follow-up of 53.3 ± 16.4 months, there was no significant change in mean QRS duration, RV function, RV end-systolic and end-diastolic dimensions, RV myocardial performance index, and functional status (including NYHA class and 6-min walk test) compared to at-discharge values. Four patients developed prosthetic valve degeneration with mild PR and without significant increase in gradient.

Conclusion :

Concomitant PVR with TOF repair in adult provides excellent mid-term outcome, with a minimal rate of pulmonary valve degeneration. It not only eases the early postoperative course but also preserves the RV function as well as functional status at mid-term.

CT quantification of ventricular volumetric parameters based on semiautomatic 3D threshold-based segmentation in porcine heart and children with tetralogy of Fallot: accuracy and feasibility

Background

To investigate the accuracy and feasibility of CT in quantification of ventricular volume based on semiautomatic three-dimensional (3D) threshold-based segmentation in porcine heart and children with tetralogy of Fallot (TOF).

Methods

Eight porcine hearts were used in the study. The atria were resected and both ventricles of the eight porcine hearts were filled with solidifiable silica gel and performed CT scanning. The water displacement volume of silica gel casting mould was referred as gold standard of ventricular volume. Results of left and right ventricular volumes measured by CT were compared with reference standard. Twenty-three children diagnosed with TOF were retrospectively included. The ventricular volumetric parameters were assessed by cardiac CT before and 6 months after surgery.

Results

Left ventricular and right ventricular volumes of porcine hearts measured by CT were highly correlated to casting mould (r=0.845, p=0.008; r=0.933, p=0.001), and there were no statistically significant differences (t=−1.059, p=0.325; t=−1.121, p=0.299). In children with TOF, right ventricular end-systole volumes 6 months after operation were higher than that before surgery, 21.93±4.44 vs 19.80±4.52 mL/m2, p=0.001. Right ventricular ejection fractions 6 months after surgery were lower compared with that before surgery 59.79%±4.26% vs 63.05%±5.04%, p=0.000.

Conclusions

CT is able to accurately assess ventricular volumetric parameters based on semiautomatic 3D threshold-based segmentation. Both of the right and left ventricular volumetric parameters could be evaluated by CT in children with TOF.

Assessment of untreated fresh autologous pericardium as material for construction of heart valve: Result at 5 years

Introduction:

Tetralogy of Fallot requiring transannular repair of the right ventricular outflow tract (RVOT) are exposed to free pulmonary insufficiency and hence inevitable right ventricular dysfunction. This study analyzes the function and structure of untreated autologous pericardium monocusp used to create a competent pulmonary valve.

Materials and Methods:

This is a retrospective analysis of 52 cases operated between December 2006 and December 2012. Untreated autologous pericardium was used for creating a competent pulmonary valve following a transannular patch. They are followed for functional and structural assessment of the pulmonary valve by echocardiography. Positron emission tomography (PET) with 18 fluorodeoxyglucose was performed in two cases for profiling the pulmonary valve.

Results:

Median age was 10.5 years (1–38). The follow-up was complete for 42 (80.76%) patients for 3 years and 25 (48.07%) patients for 5 years. The RVOT gradient was 42 mmHg (16–96) in the year of surgery, which reduced to 26 mmHg (10–58) and pulmonary insufficiency that was present in 8.3% of patients in 1^st year was witnessed in 22.7% in the 5^th year of follow-up. The monocusp patch was successful in creating a competent valve while maintaining its structure at 3 years; however, it became distorted and retracted at 5 years of follow-up. There was no calcification in any of the patients. PET-computed tomography confirmed the uptake of glucose by monocusp at 1 year of follow-up.

Conclusion:

The untreated autologous pericardium functioned well when it was used to create a competent pulmonary valve at short term and midterm. Although it changed in its structure; there was no calcification at 5 years of follow-up.

Myocardial protection and clinical outcomes in Tetralogy of Fallot patients undergoing intracardiac repair: a randomized study of two cardioplegic techniques

Background:

Myocardial protection in Tetralogy of Fallot patients undergoing intracardiac repair is suboptimal due to hypertrophied right ventricle. Hypertrophied myocardium is more susceptible to poor myocardial preservation because of inadequate capillary density as compared to the myocytes. There is a capillary to myocyte ratio mismatch. But del Nido Cardioplegia owing to its less viscosity is able to get more evenly distributed under hypothermic cardiopulmonary bypass as opposed to blood Cardioplegia. We hypothesized that the del Nido Cardioplegia technique, would be beneficial in myocardial protection because of its composition and method of delivery, leading into better early and late clinical outcomes in patients undergoing Tetralogy of Fallot repair as compared to blood cardioplegia reconstituted using St Thomas Cardioplegia solution. The objective of the study was to identify a better technique of myocardial preservation in Tetralogy of Fallot patient.

Methods:

In total, 56 Tetralogy of Fallot patients undergoing intracardiac repair under mild hypothermic cardiopulmonary bypass were randomly allocated to receive antegrade Cardioplegia with either standard blood Cardioplegia (Group I) or del Nido Cardioplegia (Group II). Preoperative as well as postoperative data including echocardiographic parameters for right ventricle functions, creatine kinase MB level, inotropic requirement, mechanical ventilation duration, intensive care unit stay and hospital mortality were evaluated.

Results:

Inotropic score in the first 24 hours postoperatively was significantly lower in Group II compared to Group I (13.4 ± 7.2 vs. 21.2 ± 9.6, p = 0.003). Creatine kinase MB level (ng/mL) was comparable between the groups. Echocardiographic parameters for right ventricle functions were also comparable between the groups during early as well as after 3 to 6 months postoperatively.

Conclusion:

Del Nido Cardioplegia is equally efficacious in providing myocardial protection during intracardiac repair under mild hypothermic cardiopulmonary bypass in Tetralogy of Fallot patients as compared to blood Cardioplegia solution with the added benefit of reducing inotropic requirement in first 24 hours postoperative period.

Left Ventricular Stiffness in Adolescents and Young Adults with Repaired Tetralogy of Fallot

Left ventricular (LV) remodeling after tetralogy of Fallot (TOF) repair may influence LV stiffness. We hypothesized that LV stiffness is altered after TOF repair and related to myocardial calibrated integrated backscatter (cIB) and LV diastolic myocardial deformation. Seventy-seven TOF patients and 80 controls were studied. LV stiffness was assessed by diastolic wall strain (DWS) as defined by (LVPW_systole-LVPW_diastole)/LVPW_systole, where LVPW is LV posterior wall thickness, and stiffness index as defined by (E/e/LV end-diastolic dimension), where E and e are respectively early diastolic transmitral inflow and mitral annular velocities. Septal and LVPW cIB and LV diastolic strain rates were determined. Patients had significantly lower DWS (p < 0.001), higher stiffness index (p < 0.001), and greater cIB (p < 0.001). LV DWS correlated negatively with LV stiffness index (r = -0.31, p < 0.001), septal cIB (r = -0.21, p = 0.01), E/e ratio (r = -0.30, p < 0.001) and RV end-diastolic area (r = -0.31, p < 0.001), and positively with LV early (r = 0.33, p < 0.001) and late (r = 0.20, p = 0.01) diastolic strain rates and RV fractional area change (FAC) (r = 0.24, p = 0.003). Multivariate analysis revealed E/e (β = -0.26, p = 0.008), RV end-diastolic area (β = -0.20, p = 0.02), and RV FAC (β = 0.18, p = 0.01) as significant correlates of DWS. Left ventricular stiffening occurs after TOF repair and is related to impaired LV diastolic myocardial deformation, myocardial cIB, and RV volume overload.