2139Left atrial dysfunction assessed by strain correlates with symptoms and severity of aortic stenosis

Background

Aortic stenosis (AS) results in high pressure afterload causing detrimental effect especially on the left chambers. Structural and functional changes of the left ventricle (LV) usually corresponds to concomitant remodelling of the left atrium (LA). However, how this pressure afterload specifically affects LA function and whether the study of LA function could help in stratifying patients with different degree of AS it is not known.

Purpose

We aim to evaluate the differences in LA and LV function according different degree of AS by standard and speckle tracking echocardiographic.

Methods

From January 2016 to May 2018 we recruited 135 patients referring to our echo-lab with diagnosis of AS (mean age 79.5±4.4; 60/55% female). We divided this population according to AS severity in patients with moderate AS, severe asymptomatic and severe symptomatic AS and matched with 35 control group with no aortic stenosis (n=45, mean age: 77.6±4.5). All patients underwent standard and 2-dimensional speckle tracking echocardiography computing global longitudinal strain (GLS) of LV and peak atrial strain of LA (PALS).

Results

In all patients PALS was a good predictor of E/e' ratio after correction for LV EF and age (p<0.001, β: −0.48). LVEF and GLS progressively decreased together with worsening of AS degree, as well as parameters of geometry and function of LA (Table1). By excluding patients with LV dysfunction the reduction gradient of parameters of LA geometry and function was still present. However, when severe symptomatic with asymptomatic severe AS are compared, no difference in E/e' ratio was found while both GLS and PALS were significantly reduced (both p<0.0001).

Variables Overall population (180) Control (45) Moderate AS (45) Severe asympt AS (45) Severe sympt. AS (45) p LVEF 65.0±11.1 67.7±5.6 69.4±8.5 66.1±10.7 59.5±13.5 0.0001 GLS −20.4±4.1 −23.1±2.4 −21.5±2.9 −21.4±3.2 −17.1±4.3 0.0001 LA vol index 41.6±21.5 28.2±10.4 40.1±19.7 39.8±16.7 52.3±24.9 0.0001 LA strain 23.6±10.9 30.8±10.3 27.8±9.2 24.4±9.7 15.2±7.1 0.0001 LA reservoir 46.4±15.9 51.9±11.5 53.0±15.0 48.3±14.1 37.2±16.1 0.0001 Ee' ratio 14.8±7.0 9.6±2.7 13.7±6.3 15.4±6.2 19.3±7.2 0.0001

Conclusions

LA function seems to progressively decrease according to the degree of AS, independently from LV function. Significant difference was found between parameters of LA remodelling and dysfunction between symptomatic and asymptomatic AS patients. The assessment of LA function by strain may help stratify the patients with AS, identifying those who need intensive medical/surgical treatment.

New detection configuration for low activity levels of PET tracers during the analysis of plasma samples

A new radio-HPLC detection system for measuring radioactivity in plasma samples during Positron Emission Tomography [PET] studies was developed. It is based on detecting both the positron and one of the annihilation photons. The system focused on improving the measurement of radioactivity concentrations on an unmetabolized positron emitting a radiopharmaceutical [PER] in the presence of its radioactive metabolites, all containing the same positron emitter. This paper presents a new detection configuration that improves the minimal detectible activity (MDA), simplify the measuring systems and reduces the error caused by the metabolites. The detector is based on a plastic scintillator and a BGO scintillation crystal, that produces different light output spectra for signal and noise events. By summing the positron and the annihilated photon light outputs, different spectra are obtained for the metabolite and for the parent compound tracer and for tracer marked by different positron emitting isotopes. This new detection system can improve quantitative analysis of plasma samples. The spectrum change provides up to a three-fold improvement in sensitivity compared to the currently used detection systems that measure only the annihilation coincidence events. Results showed that for ¹¹C the MDA was improved by approximately 520%. Furthermore, it provides the additional advantage of reliability by providing a method for separating the signal and noise readings from the gross detector readout. Accurate reconstruction algorithm of the signal was achieved over a wide measuring range even when the signal was only 5% of the gross measurement.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

Direct observation of electrons in microwave vacuum components

Apparatus which is used to directly observe electrons in microwave vacuum components was designed and implemented into a WR-284 like waveguide operated at 2.85 GHz with up to approx. 1 MW power. To generate desired electric field levels for driving secondary emission, the waveguide structure is manipulated by reducing the test section height to 6 mm from the standard WR-284 rectangular waveguide height of 34 mm. Both test and standard sections were operated in the dominant TE₁₀ mode. A 1 mm aperture was cut into the broadside wall of the waveguide section enabling a portion of electrons in the waveguide to enter a properly biased electron multiplier tube mounted atop of the test section. Waveforms are presented showing the direct measurement of electrons, providing a local detection method with nanosecond temporal resolution. Future work will incorporate the test setup for multipactor studies.

Abstract P6-09-04: Predictive factors for considering to avoid axillar lymphadenectomy in selected node positive breast cancer patients after neoadjuvant chemotherapy

Background:

To perform a systematic axillar lymphadenectomy (ALND) in clinical node positive (N+) patients after neoadjuvant chemotherapy (NACT) is currently under discussion. We aimed to study which factors are related to a pathological complete axillar response (ypN0) after NACT in order to select which patients could benefit from a sentinel lymph node biopsy without interfering with survival.

Material and methods

N+ patients who underwent ALND after NACT between June 2008 and December 2016 were retrospectively analyzed. Clinical features, molecular and histological factors, recurrence and specific mortality rates were compared between patients achieving a complete pathological axillary response vs not (ypN0 vs ypN+).

Results

345 N+ patients were reviewed. After NACT, 137 (39.6%) become ypN0[CF1] , 9 (2.6%) ypN1 mic, 113 (32.7%) ypN1, 60 (17.3%) ypN2 and 22 (6.4%) N3. Univariate analysis results regarding the predictive factors for ypN0 are detailed in [table 1]. Multivariate analyses showed molecular subtype (TN and Her2+) and clinical response as independent predictors of ypN0 [table 2]. After a mean follow-up of 58 months, overall survival was statistically superior in ypN0 vs ypN1 (p= 0.001).

Table 1.Predictive factors for ypN0 YpN0 (n = 137)YpN+ (n = 208)pAge (mean, years)58.3 ± 13.2758.59 ± 12.340.799BMI (mean)27.8±5.4927.8±5.360.973Dosis of QT (median)(%)  0.575IIA6 (31.6)13 (68.4) IIB71 (39.3)110 (60.8) IIIA28 (36.8)48 (63.2) IIIB24 (43.6)31 (56.4) IIIC7 (58.3)5 (41.7) Radiological image(%)  0.930Nodule77 (38.1)125 (61.9) Non-mass distortion10 (43.5)13 (56.5) Radiological size (median)32 (0-115)29 (0-130)0.246Suspicious a-LN by US(%)  0.486130 (30.9)37 (24.3) 25 (5.2)14 (9.2) &gt;257 (58.8)91 (59.9) Histological subtype(%)  0.093Invasive Ductal Carcinoma133 (40.9)192 (59.1) Invasive Lobular Carcinoma2 (20)8 (80) Others2 (22.2)7 (78.8) Nottingham grade(%)  &lt;0.001G11 (6.2)15 (93.8) G244 (28.6)110 (71.4) G386 (53.4)75 (46.6) Molecular-like subtype(%)  &lt;0.001Luminal A-like2 (5.3)36 (94.7) Luminal B-like (Her2 -)21(18.1)95 (81.9) Luminal B-like (Her2 +)40 (63.5)23 (36.5) HER-2 enriched (non luminal)43 (74.1)15 (25.9) Triple Negative31 (44.9)38 (55.1) Vascular invasion19 (42.2)26 (57.8)0.889Clinical Response(%)  &lt;0.001Complete61 (75.3)20 (24.7) Partial69 (31.8)148 (68.2) No response6 (20.7)23 (79.3) Progression1 (10)9 (90) Percentage are given per row.

Table 2.Multivariate analysis logistic regression of clinical predictive factors of ypN0. OR95% Confidence Intervalp valueMolecular subtype   No-luminal vs Luminal7,7483,913-15,343&lt;0,001Clinical response   Response vs not response6,8491,834-25,5710,04OR: Odd ratio. No-luminal includes: luminal B (HER2 +), HER2 Henriched and triple negative. Luminal includes: Luminal A and Luminal B (HER2 -).

Conclusions

A remarkable percentage of N+ became ypN0 after NATC. Molecular subtype and complete clinical response were independent predictive factors of ypN0. We propose to offer the benefit of a targeted axillary procedure in those patients.

Citation Format: Fernandez-Gonzalez S, Falo Zamora C, Nuñez D, Vethencourt A, Pla MJ, Soler T, Guma A, Perez X, Gil M, Ponce J, Garcia A. Predictive factors for considering to avoid axillar lymphadenectomy in selected node positive breast cancer patients after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-09-04.

Abstract P2-08-58: Prognostic factors of survival in node positive breast cancer patients after neoadjuvant chemotherapy in a large series after 5y follow-up: Can response overcome the poor prognosis of nodal stage?

Background: Status of the axilla is one of the most significant prognostic factors in breast cancer (BC) patients. On the other hand, response to neoadjuvant chemotherapy (NACT) is related to survival. The aim of the present study is to analyze which prognostic factors impact most on Node positive (N+) BC patient survival after NATC. Material and methods: Retrospective analyses on a series of N+ BC patients treated with NATC based on anthracyclines and taxanes +/- trastuzumab if HER2 positive tumors, between June 2008 and December 2016. Clinical, radiological and pathological outcomes have been evaluated. Residual cancer burden (RCB) 1 and the neoadjuvant response index (INR) 2 have been recorded. Survival was calculated with Kaplan-Meier survival curve since the start of NATC to the first documented disease recurrence (DFS) or death (OS). Hazard ratios (HRs) with 95% CIs were estimated with cox proportional hazards regression analysis and subgroups were compared with a two-sided log-rank test. Results: A total of 345 N+ BC patients were included. Pathological complete response was achieved in 72 (20.8%) patients. After NACT, 137 (39.6%) become ypN0, 9 (2.6%) ypN1 mic, 113 (32.7%) ypN1, 60 (17.3%) ypN2 and 26 (7.6%) N3. Those independent predictive factor of ypN0 were molecular subtype (TN and Her2+) with OR: 7.7, p&lt;0.001 and clinical response with OR 6.88, p: 0.04. At a mean follow-up of 58 months there have been 73 (21.1%) recurrences: 9 (2.3%) local, 45 (13%) systemic, 15 (4.3%) systemic+ local, 3 (0.9%) axilla, 1 (0.3%) supraclavicular. The estimated 5y OS was 87.8%. The univariate analysis according to DSF is detailed in Table1.

Adjusted univariate anaalysis cox regression of clinical and pathological factors of desease free survivalBMI10.989-1.010.963AGE0.9960.953-1.0420.876Dose NATC0.9940.979-1.0080.402Clinical Stage1.4021.077-1.8260.012Rx Image1.260.803-1.9940.311Rx size1.0090.995-1.0240.217Number suspicious ALN1.0950.801-1.4970.57Molecular subtype TN,HER20.8800.534-1.450.616Nottinghan grade1.0460.753-1.4530.789Histological subtype1.4651.044-2.0570.27MOlecular subtype1.1510.956-1.3850.137Vascular invasion1.6761.137-24710.009Clinical response2.3691.709-3.284&lt;0.001Fibrosis tumor bed0.980.972-0.989&lt;0.001Nodal fibrosis&gt;50%1.7950.874-3.6860.111Pathological tumoral response1.6861.175-2.4180.005ypN03.561.853-6.838&lt;0.001NRI0.330.192-0.565&lt;0.001RCB1.2741.106-1.4680.001

In the multivariate model those parameters that were independently prognostic were clinical response HR: 5.44 (IC95% 2.275-13.042, p&lt;0.001) and clinical stage HR: 2.364 (IC95% 1.018-5.490, p: 0.045). Conclusions: The most significant prognostic factor in our N+ series was response to NATC, followed by clinical stage. Those independently predictive factors of axillar response (ypN0) were molecular subtype (TN and Her2+) and clinical response. In conclusion, in those patients with chemo sensitive tumors, lymphadenectomy could be safely spared with a more selective axillary approach.

Citation Format: Fernandez S, Garcia A, Vethencourt A, Vazquez S, Petit A, Pla MJ, Ortega R, Pérez J, Gil M, Ponce J, Pernas S, Lopez A, Falo C. Prognostic factors of survival in node positive breast cancer patients after neoadjuvant chemotherapy in a large series after 5y follow-up: Can response overcome the poor prognosis of nodal stage? [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-58.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

Unified Strategy for 1,5,9- and 1,5,7-Triols via Configuration-Encoded 1,5-Polyol Synthesis: Preparation and Coupling of C15-C25 and C26-C40 Fragments of Tetrafibricin

Diverse classes of natural products contain chiral 1,5,9- and 1,5,7-triol stereotriads, including the novel fibrinogen receptor antagonist tetrafibricin. Biological activities associated with compounds containing these motifs warrant targeted synthetic strategies to 1,5-polyol families from cheap and easily accessible reagents while avoiding the need to determine configurations at each alcohol stereocenter. In the accompanying paper, we present a solution to these problems via an iterative configuration-encoded strategy that exploits Julia-Kocienski couplings of enantiopure α-silyloxy-γ-sulfononitrile building blocks. The stereocontrol is unambiguous, and the building blocks are available in multigram quantities via asymmetric catalysis. This approach efficiently accessed a C26-C40 subunit of tetrafibricin that contains a syn, syn-1,5,9-triol and all of the stereochemistry and functionality needed to advance toward tetrafibricin. A modification afforded the anti, syn-1,5,7-triol within the C15-C25 fragment of tetrafibricin by merging 1,5-polyol synthesis with diastereoselective intramolecular conjugate addition. The union of the C15-C25 and C26-C40 fragments was achieved via a BF₃·OEt₂-mediated Mukaiyama aldol construction with high 1,3- anti stereoinduction, revealing some unexpected insights on the impact of silyl protecting groups on 1,3- anti diastereocontrol by a β-siloxyaldehyde aldol acceptor. Directed 1,3- anti reduction completed the stereostructure of the C15-C40 portion of tetrafibricin, with configurations established by a combination of NMR experiments.