Twenty-Three-Year Experience With the Arterial Switch Operation: Expectations and Long-Term Outcomes

We aimed to describe the short- and long-term outcomes of patients after an arterial switch operation (ASO) at a single institution during a 23-year period. A retrospective chart review of all patients <18 months of age who underwent an ASO between January 1995 and March 2018 at Texas Children's Hospital, Houston, TX was performed. Primary endpoints include mortality and reintervention. Perioperative mortality was defined as mortality occurring in-hospital and/or <30 days after surgery. Survival and freedom-from-reintervention were analyzed using Kaplan-Meier method, log-rank tests, and Cox regression models. The cohort included 394 patients. Diagnoses included 204 patients (52%) with intact ventricular septum, 137 (35%) with a ventricular septal defect, 17 (4%) with a ventricular septal defect and left ventricular outflow tract obstruction (LVOTO), and 36 (9%) with Taussig-Bing anomaly. Median age at surgery was 8 days (range: 1 day to 17 months) and median weight was 3.4 (range: 0.8-12.0) kg. Overall perioperative mortality was 1.3% (n = 5), 0.3% (n = 1) since 1999. Overall survival at 5, 10, and 15 years was 98.2%, 97.8%, and 97.8%, respectively. Perioperative morality was associated with prematurity (P = 0.012), <2.5 kg (P< 0.001), and longer circulatory arrest (P = 0.024) after univariate analysis. Reintervention was associated with a longer cross-clamp time (P < 0.001), <2.5 kg (P = 0.009), LVOTO resection (P = 0.047), and genetic syndrome (P= 0.011) after multivariable analysis. Current ASO expectations should include a perioperative mortality risk of <1% and good long-term survival. Reinterventions are more frequent in patients <2.5 kg, concomitant LVOTO resection, a genetic syndrome, and longer cross-clamp time.

Pulmonary Artery Banding for Children With Dilated Cardiomyopathy: US Experience

Pulmonary artery band placement is a recently described therapeutic strategy for dilated cardiomyopathy with preserved right ventricular function, originally reported from Germany.1 We present the results of the multicenter retrospective study of pulmonary artery band experience in the United States, with comparison to the German experience. Five centers contributed a total 14 patients (median age 5 months, interquartile range 3.5-10). Mechanical ventilation was required in 9/12 (75%) patients and inotropes were used in 13/14 (93%) patients preoperatively. Ultimately, 4 (29%) patients experienced cardiac recovery, 8 (57%) were bridged to cardiac transplantation (6 with ventricular assist device placement), and 2 (14%) died. Although both the US and Germany series demonstrated high prevalence of achieving patients' individual target (either cardiac recovery or transplant), the mode of success was different (recovery rate: <1/3 in the United States and >2/3 in Germany). Lower recovery rate may be a reflection of sicker preoperative status, and thereby a more advanced stage of heart failure (preoperative intubation: >2/3 in the United States vs <1/3 in Germany). Further studies would be warranted to gain more insight into patient selection as well as optimal timing for the intervention.

Pulmonary artery pulsatility index predicts prolonged inotrope/pulmonary vasodilator use after implantation of continuous flow left ventricular assist device

OBJECTIVE

Predictors of right ventricle (RV) dysfunction after continuous-flow left ventricular assist device (CF-LVAD) implantation in children are not well described. We explored the association of preimplantation Pulmonary Artery Pulsatility index (PAPi) and other hemodynamic parameters as predictors of prolonged postoperative inotropes/pulmonary vasodilator use after CF-LVAD implantation.

DESIGN

Retrospective chart review.

SETTING

Single tertiary care pediatric referral center.

PATIENTS

Patients who underwent CF-LVAD implantation from January 2012 to October 2017.

INTERVENTIONS

Preimplantation invasive hemodynamic parameters were analyzed to evaluate the association with post-CF-LVAD need for prolonged (>72 hours) use of inotropes/pulmonary vasodilators.

MEASUREMENTS AND MAIN RESULTS

Preimplantation cardiac catheterization data was available for 12 of 44 patients who underwent CF-LVAD implant during the study period. Median (IQR) age and BSA of the cohort were 15.3 years (10.2, 18) and 1.74 m² (0.98, 2.03). Group 1 (n = 6) included patients with need for prolonged inotropes/pulmonary vasodilator use after CF-LVAD implantation and Group 2 (n = 6) included those without. Baseline demographic parameters, cardiopulmonary bypass time, and markers of RV afterload (pulmonary vascular resistance, PA compliance and elastance) were similar among the two groups. PAPi was significantly lower in group 1 compared to group 2 (0.96 vs 3.6, respectively; P = .004). Post-LVAD stay in the intensive care unit was longer for patients in group 1 (46 vs 23 days, P = .52). Brain natriuretic peptide was significantly higher at 3 months after implantation in group 1; P = .01.

CONCLUSIONS

The need for inotropes/pulmonary vasodilators in the postoperative period can be predicted by the preimplantation intrinsic RV contractile reserve as assessed by PAPi rather than the markers of RV afterload. Further investigation and correlation with clinical outcomes is needed.

First Measurements of Absolute Branching Fractions of the Ξ_{c}^{0} Baryon at Belle

We present the first measurements of absolute branching fractions of Ξ_{c}^{0} decays into Ξ^{-}π^{+}, ΛK^{-}π^{+}, and pK^{-}K^{-}π^{+} final states. The measurements are made using a dataset comprising (772±11)×10^{6} BB[over ¯] pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. We first measure the absolute branching fraction for B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0} using a missing-mass technique; the result is B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})=(9.51±2.10±0.88)×10^{-4}. We subsequently measure the product branching fractions B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→Ξ^{-}π^{+}), B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→ΛK^{-}π^{+}), and B(B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0})B(Ξ_{c}^{0}→pK^{-}K^{-}π^{+}) with improved precision. Dividing these product branching fractions by the result for B^{-}→Λ[over ¯]_{c}^{-}Ξ_{c}^{0} yields the following branching fractions: B(Ξ_{c}^{0}→Ξ^{-}π^{+})=(1.80±0.50±0.14)%, B(Ξ_{c}^{0}→ΛK^{-}π^{+})=(1.17±0.37±0.09)%, and B(Ξ_{c}^{0}→pK^{-}K^{-}π^{+})=(0.58±0.23±0.05)%. For the above branching fractions, the first uncertainties are statistical and the second are systematic. Our result for B(Ξ_{c}^{0}→Ξ^{-}π^{+}) can be combined with Ξ_{c}^{0} branching fractions measured relative to Ξ_{c}^{0}→Ξ^{-}π^{+} to yield other absolute Ξ_{c}^{0} branching fractions.

Observation of Ξ(1620)^{0} and Evidence for Ξ(1690)^{0} in Ξ_{c}^{+}→Ξ^{-}π^{+}π^{+} Decays

We report the first observation of the double strange baryon Ξ(1620)^{0} in its decay to Ξ^{-}π^{+} via Ξ_{c}^{+}→Ξ^{-}π^{+}π^{+} decays based on a 980  fb^{-1} data sample collected with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The mass and width are measured to be 1610.4±6.0(stat)_{-4.2}^{+6.1} (syst)  MeV/c^{2} and 59.9±4.8(stat)_{-7.1}^{+2.8}(syst)  MeV, respectively. We obtain 4.0σ evidence of the Ξ(1690)^{0} with the same data sample. These results shed light on the structure of hyperon resonances with strangeness S=-2.

Observation of Transverse Λ/Λ[over ¯] Hyperon Polarization in e^{+}e^{-} Annihilation at Belle

We report the first observation of the spontaneous polarization of Λ and Λ[over ¯] hyperons transverse to the production plane in e^{+}e^{-} annihilation, which is attributed to the effect arising from a polarizing fragmentation function. For inclusive Λ/Λ[over ¯] production, we also report results with subtracted feed-down contributions from Σ^{0} and charm. This measurement uses a dataset of 800.4  fb^{-1} collected by the Belle experiment at or near a center-of-mass energy of 10.58 GeV. We observe a significant polarization that rises with the fractional energy carried by the Λ/Λ[over ¯] hyperon.

Search for a Light CP-odd Higgs Boson and Low-Mass Dark Matter at the Belle Experiment

We report on the first Belle search for a light CP-odd Higgs boson, A^{0}, that decays into low mass dark matter, χ, in final states with a single photon and missing energy. We search for events produced via the dipion transition ϒ(2S)→ϒ(1S)π^{+}π^{-}, followed by the on-shell process ϒ(1S)→γA^{0} with A^{0}→χχ, or by the off-shell process ϒ(1S)→γχχ. Utilizing a data sample of 157.3×10^{6} ϒ(2S) decays, we find no evidence for a signal. We set limits on the branching fractions of such processes in the mass ranges M_{A^{0}}<8.97  GeV/c^{2} and M_{χ}<4.44  GeV/c^{2}. We then use the limits on the off-shell process to set competitive limits on WIMP-nucleon scattering in the WIMP mass range below 5  GeV/c^{2}.

First Evidence for cos2β>0 and Resolution of the Cabibbo-Kobayashi-Maskawa Quark-Mixing Unitarity Triangle Ambiguity

We present first evidence that the cosine of the CP-violating weak phase 2β is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B^{0}→D^{(*)}h^{0} with D→K_{S}^{0}π^{+}π^{-} decays, where h^{0}∈{π^{0},η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the ϒ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6}BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6}BB[over ¯] pairs recorded by the Belle detector. The results of the measurement are sin2β=0.80±0.14(stat)±0.06(syst)±0.03(model) and cos2β=0.91±0.22(stat)±0.09(syst)±0.07(model). The result for the direct measurement of the angle β of the CKM Unitarity Triangle is β=[22.5±4.4(stat)±1.2(syst)±0.6(model)]°. The measurement assumes no direct CP violation in B^{0}→D^{(*)}h^{0} decays. The quoted model uncertainties are due to the composition of the D^{0}→K_{S}^{0}π^{+}π^{-} decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e^{+}e^{-}→cc[over ¯] data sample. CP violation is observed in B^{0}→D^{(*)}h^{0} decays at the level of 5.1 standard deviations. The significance for cos2β>0 is 3.7 standard deviations. The trigonometric multifold solution π/2-β=(68.1±0.7)° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.

Observation of ϒ(2S)→γη_{b}(1S) Decay

We report the observation of ϒ(2S)→γη_{b}(1S) decay based on an analysis of the inclusive photon spectrum of 24.7  fb^{-1} of e^{+}e^{-} collisions at the ϒ(2S) center-of-mass energy collected with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We measure a branching fraction of B[ϒ(2S)→γη_{b}(1S)]=(6.1_{-0.7-0.6}^{+0.6+0.9})×10^{-4} and derive an η_{b}(1S) mass of 9394.8_{-3.1-2.7}^{+2.7+4.5}  MeV/c^{2}, where the uncertainties are statistical and systematic, respectively. The significance of our measurement is greater than 7 standard deviations, constituting the first observation of this decay mode.

Pulsatile Glenn as long-term palliation for single ventricle physiology patients

OBJECTIVE

There are limited studies analyzing pulsatile Glenn as a long-term palliation strategy for single ventricle patients. This study sought to determine their outcomes at a single institution.

DESIGN

A retrospective review was performed.

SETTING

Study performed at a single pediatric hospital.

PATIENTS

All single ventricle patients who underwent pulsatile Glenn from 1995 to 2016 were included.

OUTCOME MEASURES

Pulsatile Glenn failure was defined as takedown, transplant, or death. Further palliation was defined as Fontan, 1.5, or biventricular repair. Risk factors were assessed by Cox multivariable competing risk analyses.

RESULTS

Seventy-eight patients underwent pulsatile Glenn at age 9 months (interquartile range, 5-14). In total, 28% had heterotaxy, 18% had a genetic syndrome, and 24% had an abnormal inferior vena cava. There were 3 (4%) perioperative mortalities. Further palliation was performed in 41 (53%) patients with a median time-to-palliation of 4 years (interquartile range, 3-5). Pulsatile Glenn failure occurred in 10 (13%) patients with 8 total mortalities. Five- and 10-year transplant-free survival were 91% and 84%, respectively. At a median follow-up of 6 years (interquartile range, 2-8), 27 patients (35%) remained with PG (age 7 years [interquartile range, 3-11], oxygen saturation 83% ± 4%). Preoperative moderate-severe atrioventricular valve regurgitation (AVVR) (hazard ratio 7.77; 95% confidence interval 1.80-33.43; P =.005) and higher pulmonary vascular resistance (hazard ratio 2.59; 95% confidence interval 1.08-6.15; P =.031) were predictors of pulsatile Glenn failure after adjusting for covariates. Reaching further palliation was less likely in patients with preoperative moderate-severe AVVR (hazard ratio 0.22, 95% confidence interval 0.08-0.59; P =.002).

CONCLUSION

Pulsatile Glenn can be an effective tool to be used in challenging circumstances, these patients can have a favorable long-term prognosis without reducing their suitability for further palliation.

Contemporary Outcomes After Repair of Isolated and Complex Complete Atrioventricular Septal Defect

BACKGROUND

Contemporary outcomes of complete atrioventricular septal defect (CAVSD) repair, particularly for defects with associated abnormalities, is unclear. The goal of this study is to report an all-inclusive experience of CAVSD repair using a consistent surgical approach.

METHODS

All patients undergoing CAVSD repair between 1995 and 2016 at our institution were included. Patients were divided into 2 groups: isolated and complex (tetralogy of Fallot, aortic arch repair, double outlet right ventricle, and total anomalous pulmonary venous return). Survival and reoperation were analyzed using log-rank test and Gray's test, respectively. Multivariable analysis was performed with Cox regression.

RESULTS

Overall, 406 patients underwent repair: 350 (86%) isolated and 56 (14%) complex CAVSD (tetralogy of Fallot: 34, double outlet right ventricle: 7, aortic arch repair: 12, total anomalous pulmonary venous return: 3). Median age at repair was 5 months (range, 10 days to 16 years); 339 (84%) had trisomy 21. A 2-patch repair was used in 395 (97%) and the zone of apposition was completely closed in 305 (75%). Perioperative mortality was 2% and 4% in the isolated and complex groups, respectively. Perioperative mortality since 2006 was 0.9%. Median follow-up was 7 years. Overall 10-year survival and incidence of any reoperation were 92% and 11%, respectively. Complex anatomy was not a risk factor for mortality (p = 0.35), but it was for reoperation (hazard ratio [HR]: 2.6; p < 0.01). Risk factors for left atrioventricular valve reoperation were a second bypass run (HR: 2.7) and preoperative moderate or worse regurgitation (HR: 2.3).

CONCLUSIONS

Mortality after CAVSD repair is low, yet reoperation remains a significant problem. Repair of complex CAVSD can be performed with similar mortality rates.

Mechanical Circulatory Support for Single Ventricle Failure

Mechanical circulatory support (MCS) for failing single ventricle (SV) physiology is a complex and challenging problem, which has not yet been satisfactorily addressed. Advancements in surgical strategies and techniques along with intensive care management have substantially improved the outcomes of neonatal palliation for SV physiology, particularly for hypoplastic left heart syndrome (HLHS). This is associated with a steady increase in the number of SV patients who are susceptible to develop heart failure (HF) and would potentially require MCS at a certain stage in their palliation. We have reviewed the literature regarding the reported modalities of MCS use in the management of SV patients. This includes analysis of various devices and strategies used for failing circulation at distinct stages of the SV pathway: after neonatal palliation, after the superior cavo-pulmonary connection (SCPC), and after total cavo-pulmonary connection (TCPC).

Observation of an Excited Ω^{-} Baryon

Using data recorded with the Belle detector, we observe a new excited hyperon, an Ω^{*-} candidate decaying into Ξ^{0}K^{-} and Ξ^{-}K_{S}^{0} with a mass of 2012.4±0.7(stat)±0.6(syst)  MeV/c^{2} and a width of Γ=6.4_{-2.0}^{+2.5}(stat)±1.6(syst)  MeV. The Ω^{*-} is seen primarily in ϒ(1S),ϒ(2S), and ϒ(3S) decays.

Search for B^{-}→μ^{-}ν[over ¯]_{μ} Decays at the Belle Experiment

We report the results of a search for the rare, purely leptonic decay B^{-}→μ^{-}ν[over ¯]_{μ} performed with a 711  fb^{-1} data sample that contains 772×10^{6}  BB[over ¯] pairs, collected near the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The signal events are selected based on the presence of a high momentum muon and the topology of the rest of the event showing properties of a generic B-meson decay, as well as the missing energy and momentum being consistent with the hypothesis of a neutrino from the signal decay. We find a 2.4 standard deviation excess above background including systematic uncertainties, which corresponds to a branching fraction of B(B^{-}→μ^{-}ν[over ¯]_{μ})=(6.46±2.22±1.60)×10^{-7} or a frequentist 90% confidence level interval on the B^{-}→μ^{-}ν[over ¯]_{μ} branching fraction of [2.9,10.7]×10^{-7}.

Circumflex aorta with double aortic arch in an infant

Circumflex aorta and double aortic arch are two forms of rare vascular rings. We present a case of an infant who was diagnosed with circumflex aorta and double aortic arch, and describe the surgical management of this rare anomaly.

Selective trihydroxylated azepane inhibitors of NagZ, a glycosidase involved in Pseudomonas aeruginosa resistance to β-lactam antibiotics

The synthesis of a series of d-gluco-like configured 4,5,6-trihydroxyazepanes bearing a triazole, a sulfonamide or a fluorinated acetamide moiety at C-3 is described. These synthetic derivatives have been tested for their ability to selectively inhibit the muropeptide recycling glucosaminidase NagZ and to thereby increase sensitivity of Pseudomonas aeruginosa to β-lactams, a pathway with substantial therapeutic potential. While introduction of triazole and sulfamide groups failed to lead to glucosaminidase inhibitors, the NHCOCF₃ analog proved to be a selective inhibitor of NagZ over other glucosaminidases including human O-GlcNAcase and lysosomal hexosaminidases HexA and B.

Current status and future perspectives of the PumpKIN trial

Similar to the adult experience, the use of continuous-flow ventricular assist devices (VADs) has been increasing in the pediatric population. According to the PediMACS registry, continuous-flow VAD currently accounts for >60% of the durable device implantations in the U.S. Nonetheless, the continuous-flow VADs currently in use are designed for adults; this inevitably causes the patient-device size mismatch issue, especially when applied for small children. Pulsatile VADs, therefore, represent the only practical option for this group of patients despite the known risk profile of pulsatile VADs. To address such a frustrating reality, the National Heart, Lung, and Blood Institute (NHLBI) launched the Pediatric Circulatory Support Program in 2004, which is the predecessor of the so-called PumpKIN (Pump for Kids, Infants, and Neonates) program. The goal of this program was to develop mechanical circulatory support devices specifically designed for small children. As a result of extensive efforts of the multi-disciplinary team involving clinicians, scientists, manufactures, and federal agencies, the Infant Jarvik 2015, one of the original devices within the Pediatric Circulatory Support Program, has become the first continuous-flow VAD specifically designed for small children that obtained the Investigational Device Exemption (IDEs) from the U.S. Food and Drug Administration (FDA). This approval is a prerequisite to initiate a clinical trial (i.e., the PumpKIN trial). This article describes the history, current status, and future perspectives of this extremely challenging project, with a focus on the lessons we have learned over the decade.

Management of Hemostasis for Pediatric Patients on Ventricular-Assist Devices

Ventricular-assist devices (VADs) have seen increased utilization in the pediatric population. Formerly, this therapeutic modality was limited to only the pulsatile VAD, EXCOR (Berlin Heart GmbH). However, the continuous flow VAD devices, HeartMate II (Abbott Inc.) and HeartWare (Medtronic Inc.), are now increasingly used in this population. Postoperatively, VAD patients are acutely anticoagulated using unfractionated heparin, often beginning 24 to 48 hours after VAD placement. Once the patient is stabilized and ready to transition to a lower acuity or outpatient setting, low-molecular-weight heparin or warfarin therapy may be instituted. Also, because of the risk for thrombotic and thromboembolic complications, antiplatelet strategies are employed using medications such as aspirin, clopidogrel, or dipyridamole. Platelet-rich plasma or whole blood platelet aggregation studies, platelet function analyzer-100 (Siemens), VerifyNow (Accriva Diagnostics), or thromboelastography platelet mapping (Haemonetics) may be used to help monitor antiplatelet effects, though the interpretation of the strength of the antiplatelet effect remains difficult. Care must be taken to monitor the hematologic complications of VAD, including acquired von Willebrand syndrome, which increases the risk for bleeding, and intravascular hemolysis, which increases the risk of thrombosis. Appropriate device placement and anticoagulation management are imperative to help avoid neurological dysfunction and ischemic stroke, the most devastating potential complications of VAD therapy. As our experience grows, we continue to gain an increased understanding of the management of anticoagulation, need for antiplatelet medication, and appropriate monitoring for these critical patients.

Evidence for Isospin Violation and Measurement of CP Asymmetries in B→K^{*}(892)γ

We report the first evidence for isospin violation in B→K^{*}γ and the first measurement of the difference of CP asymmetries between B^{+}→K^{*+}γ and B^{0}→K^{*0}γ. This analysis is based on the data sample containing 772×10^{6}BB[over ¯] pairs that was collected with the Belle detector at the KEKB energy-asymmetric e^{+}e^{-} collider. We find evidence for the isospin violation with a significance of 3.1σ, Δ_{0+}=[+6.2±1.5(stat)±0.6(syst)±1.2(f_{+-}/f_{00})]%, where the third uncertainty is due to the uncertainty on the fraction of B^{+}B^{-} to B^{0}B[over ¯]^{0} production in ϒ(4S) decays. The measured value is consistent with predictions of the standard model. The result for the difference of CP asymmetries is ΔA_{CP}=[+2.4±2.8(stat)±0.5(syst)]%, consistent with zero. The measured branching fractions and CP asymmetries for charged and neutral B meson decays are the most precise to date. We also calculate the ratio of branching fractions of B^{0}→K^{*0}γ to B_{s}^{0}→ϕγ.