Multicenter Study of Survival Benefit of Cardiac Resynchronization Therapy in Pediatric and Congenital Heart Disease.

BACKGROUND: Evidence for the efficacy of cardiac resynchronization therapy (CRT) in pediatric and congenital heart disease (CHD) has been limited to surrogate outcomes. OBJECTIVES: This study aimed to assess the impact of CRT upon the risk of transplantation or death in a retrospective, high-risk, controlled cohort at 5 quaternary referral centers. METHODS: Both CRT patients and control patients were <21 years of age or had CHD; had systemic ventricular ejection fraction <45%; symptomatic heart failure; and significant electrical dyssynchrony (QRS duration z score >3 or single-site ventricular pacing >40%) at enrollment. Patients with CRT were matched with control patients via 1:1 propensity score matching. CRT patients were enrolled at CRT implantation; control patients were enrolled at the outpatient clinical encounter where inclusion criteria were first met. The primary endpoint was transplantation or death. RESULTS: In total, 324 control patients and 167 CRT recipients were identified. Mean follow-up was 4.2 ± 3.7 years. Upon propensity score matching, 139 closely matched pairs were identified (20 baseline indices). Of the 139 matched pairs, 52 (37.0%) control patients and 31 (22.0%) CRT recipients reached the primary endpoint. On both unadjusted and multivariable Cox regression analysis, the risk reduction associated with CRT for the primary endpoint was significant (HR: 0.40; 95% CI: 0.25-0.64; P < 0.001; and HR: 0.44; 95% CI: 0.28-0.71; P = 0.001, respectively). On longitudinal assessment, the CRT group had significantly improved systemic ventricular ejection fraction (P < 0.001) and shorter QRS duration (P = 0.015), sustained to 5 years. CONCLUSIONS: In pediatric and CHD patients with symptomatic systolic heart failure and electrical dyssynchrony, CRT was associated with improved heart transplantation-free survival.

Nurse Practitioner Delivered Virtual Care in a Pediatric Specialty Clinic.

INTRODUCTION: Virtual care in pediatric specialty practice has become widely used to increase access to care, one in which nurse practitioners (NPs) can play a vital role. We sought to evaluate the outcomes of virtual care provided by pediatric cardiology and electrophysiology (EP) NPs for pediatric and congenital heart disease patients. METHOD: Retrospective review of all virtual care visits performed by pediatric EP NPs between October 2019 and October 2021 at a single tertiary care center. RESULTS: NPs delivered virtual care for 287 pediatric EP evaluations for 276 patients; 132 (45%) independently, with the remaining 155 collaborating with an electrophysiologist as a shared visit. The mean age was 15.2 ± 8.9 years. DISCUSSION: NPs performed a significant subset of these visits independently and were a vital part of all visits in this study. The role of the NP in specialty pediatric virtual care should continue to be supported and advanced.

Kommerell Diverticulum: Distinctions Between Arch Side and Evaluation of Morphology, Size, And Risk.

BACKGROUND: Kommerell diverticulum (KD) is a dilated proximal aberrant right or left subclavian artery associated with either right or left aortic arches (RAA-ARSA or LAA-ALSA). Although case series suggest that KD may be a liability for vascular complications, the risk, pattern of dilation throughout the life span, and differences between arch sides are not known. METHODS: This study was a single-center retrospective review of patients of all ages with KD on cross-sectional imaging. Maximal short-axis diameter of KD (KDmax), absolute and indexed to descending aortic diameter (DAo), was correlated with age. Comparisons were made between arch sides. Patients with vascular complications were described. RESULTS: A total of 104 patients with KD were included: 68 (65%) with RAA-ALSA, 36 (35%) with LAA-ARSA, 43 (41%) asymptomatic. Although KDmax was correlated with age (RAA-ALSA r = 0.84; [P< .0001]; LAA-ARSA r = 0.51 [P = .001]), KDmax indexed to DAo was not (RAA-ALSA r = 0.14 [P = .27]; LAA-ARSA r = -0.22 [P = .21]). Patients with RAA-ALSA had larger KDmax indexed to DAo (1.02 ± 0.20 mm/mm vs 0.89 ± 0.18 mm/mm; P = .002) and more symptoms (75% vs 28%; P < .0001), and they were younger (median, 9.5 years vs 61.7 years; P < .0001). Six patients (58 to 80 years of age) had vascular complications, and all 6 had LAA-ARSA and risk factors for acquired aneurysms. CONCLUSIONS: In older patients, KDmax indexed to DAo was not larger, thus arguing against isolated KD dilation with age. Diverticula from RAA-ALSA and LAA-ARSA demonstrated different phenotypes, a finding suggesting different disease processes and likely different risk. The incidence of vascular complications was lower than in previous reports, and these complications occurred exclusively in patients with LAA-ARSA and aneurysm risk factors. This finding suggests that conservative management of asymptomatic KD is often reasonable, especially in patients with RAA-ALSA.

Effect of scaffold dilution on migration of mesenchymal stem cells from fibrin hydrogels.

OBJECTIVE: To evaluate the effect of fibrin concentrations on mesenchymal stem cell (MSC) migration out of autologous and commercial fibrin hydrogels. SAMPLE: Blood and bone marrow from six 2- to 4-year-old horses. PROCEDURES: Autologous fibrinogen was precipitated from plasma and solubilized into a concentrated solution. Mesenchymal stem cells were resuspended in fibrinogen solutions containing 100%, 75%, 50%, and 25% of the fibrinogen precipitate solution. Fibrin hydrogels were created by mixing the fibrinogen solutions with MSCs and thrombin on tissue culture plates. After incubation for 24 hours in cell culture medium, the MSCs that had migrated onto the tissue culture surface and beyond the boundary of the hydrogels were counted. This procedure was repeated with a commercial fibrin sealant. RESULTS: Hydrogel-to-surface MSC migration was detected for all fibrin hydrogels. Migration from the 25% autologous hydrogels was 7.3-, 5.2-, and 4.6-fold higher than migration from 100%, 75%, and 50% autologous hydrogels, respectively. The number of migrating cells from 100%, 75%, and 50% autologous hydrogels did not differ significantly. With commercial fibrin sealant, the highest magnitude of migration was from the 25% hydrogels, and it was 26-fold higher than migration from 100% hydrogels. The 75% and 50% hydrogels resulted in migration that was 9.5- and 4.2-fold higher than migration from the 100% hydrogels, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: MSC migration from fibrin hydrogels increased with dilution of the fibrinogen component for both autologous and commercial sources. These data supported the feasibility of using diluted fibrin hydrogels for rapid delivery of MSCs to the surface of damaged tissues.

Expansion of mesenchymal stem cells on fibrinogen-rich protein surfaces derived from blood plasma.

Mesenchymal stem cells (MSCs) are present in low density in bone marrow and culture expansion is necessary to obtain sufficient numbers for many proposed therapies. Researchers have characterized MSC growth on tissue culture plastic (TCP), although few studies have explored proliferation on other growth substrates. Using adult equine MSCs, we evaluated proliferation on fibrinogen-rich precipitate (FRP) surfaces created from blood plasma. When seeded at 1 × 10(4) cells/cm(2) and passaged five times over 10 days, MSCs on FRP in medium containing fibroblast growth factor 2 (FGF2) resulted in a ∼2.5-fold increase in cell yield relative to TCP. In FGF2-free medium, FRP stimulated a 10.4-fold increase in cell yield over TCP after 10 days, although control cultures maintained in FGF2 on TCP demonstrated that the stimulatory effect of FRP was not as lasting as that of FGF2. Chondrogenic cultures demonstrated that FRP did not affect differentiation. On TCP, MSCs seeded at 500 cells/cm(2) experienced a 4.6-fold increase in cell yield over cultures seeded at 1 × 10(4) cells/cm(2) following 10 days of expansion. In 500 cells/cm(2) cultures, FRP stimulating a two-fold increase in cell yield over TCP without affecting differentiation. Low-density FRP cultures showed a more even distribution of cells than TCP, suggesting that FRP may accelerate proliferation by reducing contact inhibition that slows proliferation. In addition, FRP appears capable of binding FGF2, as FRP surfaces pre-conditioned with FGF2 supported greater proliferation than FGF2-free cultures. Taken together, these factors indicate that substrates obtained from simple and inexpensive processing of blood enhance MSC proliferation and promote efficient coverage of expansion surfaces.