Preload stress echocardiography by using dynamic postural alteration can identify high risk patients with heart failure with reduced ejection fraction

Funding Acknowledgements

Type of funding sources: None.

Background

Haemodynamic assessment during stress testing is not commonly performed for patients with heart failure with reduced ejection fraction (HFrEF) due to its invasiveness, less feasibility, and safety concerns. Passive leg-lifting (PLL) manoeuvres have been introduced as a simple alternative for non-invasive preload stress testing; however, the haemodynamic load imposed on the cardiovascular system is unsatisfactory, which precludes the accurate assessment of the preload reserve for patients with HF.

Purpose

The purpose of this study was to assess the haemodynamic characteristics of patients with HFrEF in response to a preload stress during dynamic postural alterations by combining the semi-sitting position (SSP) and PLL. We also evaluated whether combined postural stress could be used for risk stratification for these patients.

Methods

For this study, 101 patients with HFrEF and 35 age- and sex-matched normal controls were prospectively recruited. At each postural position (i.e., baseline, SSP, and PLL), all standard echocardiographic and Doppler variables were obtained. Adverse cardiac events were prespecified as the combined endpoints of death from or hospitalisation for deteriorated HF, or sudden cardiac death. Clinical follow-up was conducted for a median of 7 months.

Results

During PLL stress, the stroke volume index (SVi) significantly increased in both controls (from 40 ± 6 to 43 ± 6 mL/m², P = 0.03) and HFrEF patients (from 31 ± 9 to 34 ± 10 mL/m², P = 0.03). Conversely, during SSP stress, the SVi significantly decreased for both controls (from 40 ± 6 to 37 ± 6 mL/m², P = 0.03) and HFrEF patients (31 ± 9 to 28 ± 8 mL/m², P = 0.03). During the follow-up period, 16 patients developed cardiac events. In patients without events, the Frank-Starling mechanism was well preserved (Fig. A). Namely, the SVi significantly increased from 31 ± 9 to 35 ± 10 mL/m² (P = 0.02) during PLL stress, while the SVi significantly decreased from 31 ± 8 to 28 ± 8 mL/m² (P = 0.02) during SSP stress. In contrast, for patients with cardiac events, the SVi did not change during postural alterations (n.s), which indicated that the failing heart operates on the flat portion of the Frank-Starling curve (Fig. A). When patients were divided into three equal sub-groups based on the total difference in the SVi during dynamic postural stress, patients with impaired preload reserve (third trimester, ΔSVi ≤ 3.0 mL/m²) showed significantly worse event-free survival than the other two sub-groups (Fig. B; P < 0.001). In a Cox proportional-hazard analysis, baseline LVEF (hazard ratio 0.93; P = 0.04), and ΔSVi during postural stress (hazard ratio 0.76; P = 0.004) were predictors of future cardiac events.

Conclusions

The combined assessment of dynamic postural stress during PLL and SPP is a simple, time-saving, and easy-to-use clinical tool for the assessment of preload reserve for patients with HFrEF. Moreover, postural stress echocardiography proved to contribute to the risk stratification for these patients.

Abstract Figure.

Cardiac resynchronization therapy improves left atrial reservoir function through resynchronization of the left atrium in patients with heart failure

Funding Acknowledgements

Type of funding sources: None.

Background

The structural remodeling of the left atrium (LA) has been proposed as an important determinant of adverse outcomes in patients with heart failure (HF). However, little is known about the potential impact of LA mechanical dyssynchrony on its reservoir function and the prognosis of patients with HF. In addition, it has not been fully investigated whether cardiac resynchronization therapy (CRT) is also beneficial to LA function.

Purposes

The purposes of this study were to test whether left ventricular (LV) dyssynchrony may negatively affect LA synchronicity and reservoir function, and to assess whether residual LA dyssynchrony after CRT affects the prognosis in patients with HF with reduced ejection fraction (HFrEF).

Methods

This study included total of 90 subjects: 40 HFrEF with a wide-QRS complex (≧130 ms), 28 HFrEF with a narrow-QRS, and 22 age- and sex-matched normal controls. LA global longitudinal strain (LA-GLS) and LA dyssynchrony were quantified using speckle-tracking strain analysis. LA dyssynchrony was defined as the maximal difference of time-to-peak strain (LA time-diff). All wide-QRS HFrEF received CRT, and event-free survival was tracked for 24 months.

Results

At baseline, HFrEF patients showed significant LA remodeling coupled with the reduced LA reservoir function, as evidenced by larger LA volume index (LAVi: 46 ± 16 vs. 30 ± 14 mL/m², P < 0.01) and smaller LA-GLS (13.0 ± 4.8 vs. 30.6 ± 10.7%, P < 0.01). Of note was that, not only LV dyssynchrony (381 ± 178 vs. 177 ± 62 ms, P < 0.01) but also LA dyssynchrony (298 ± 136 vs. 186 ± 78 ms, P < 0.01) were significantly larger in patients with HFrEF compared to normal subjects and this applied even more to patients with a wide-QRS complex. All patients with a wide-QRS complex underwent CRT, and only responders exhibited the significant decrease in LA time-diff (from 338 ± 123 to 245 ± 141 ms, P < 0.05) and increase in LA-GLS (from 11.9 ± 4.7 to 19.6 ± 10.1%, P < 0.05) in parallel with the reduction in LAVi (from 48 ± 17 to 37 ± 18 mL/m², P < 0.05) at 6 months after CRT. Receiver operating characteristic curve analysis identified the optimal cut-off value of LA time-diff at 6 months after CRT as 202 ms (P < 0.05) and that of LA-GLS as 14.6% (P < 0.05) for predicting adverse cardiac events. The patients whose LA time-diff reduced <202 ms after CRT showed significantly favorable event-free survival than the others. Similarly, the patients whose LA-GLS improved >14.6% after CRT exhibited significantly favorable event-free survival than the others (P < 0.05, respectively). Of note was that, when the patients were restricted to CRT responders only, those who showed LA time-diff less than 202 ms at 6 months after CRT almost never experienced cardiac events (P < 0.05).

Conclusions

The improved LV coordination by CRT also resulted in resynchronization of discoordinated LA wall motion and a consecutive improvement of LA reservoir function, which ultimately lead to the favorable outcome for HFrEF patients with wide-QRS complex.

Abstract Figure.

preoperative right ventricular overwork is a major determinant of residual pulmonary arterial hypertension in patients with repaired arterial septal defect

Funding Acknowledgements

Type of funding sources: None.

Background

The haemodynamic effect of atrial septal defect (ASD) is a chronic volume overload of the right heart and pulmonary vasculature. Pulmonary overcirculation is generally compensated for by the right ventricular (RV) and pulmonary arterial (PA) reserve. However, in a subset of patients, prolonged pulmonary overcirculation insidiously induces obstructive pulmonary vasculopathy, which results in postoperative residual pulmonary arterial hypertension (PAH) after ASD closure. Postoperative PAH is a major concern because it is closely associated with poor outcomes and impaired quality of life. However, to date, no clinically robust predictors of postoperative residual PAH have been clearly identified.

Purpose

This study sought to assess the haemodynamic characteristics of ASD patients in terms of mechano-energetic parameters and to identify the predictors of postoperative residual PAH in these patients.

Methods

A total of 120 ASD patients (age: 58 ± 17 years) and 46 normal controls were recruited. As previously reported, the simplified RV contraction pressure index (sRVCPI) was calculated as an index of RV external work by multiplying the tricuspid annular plane systolic excursion (TAPSE) by the pressure gradient between the RV and right atrium. RV- PA coupling was evaluated using TAPSE divided by PA systolic pressure as an index of the RV length-force relationship. These parameters were measured both at baseline and 6 months after ASD closure.

Results

As expected, baseline sRVCPI was significantly greater in patients with ASD than in controls (775 ± 298 vs. 335 ± 180 mm Hg • mm, P < 0.01), which indicated significant "RV overwork". As a result, RV-PA coupling in ASD patients was significantly impaired compared to that in controls (0.9 ± 0.8 vs. 3.5 ± 1.7 mm/mm Hg, P < 0.01). All 120 ASD patients underwent transcatheter or surgical shunt closure; 15 of them had residual PAH after closure. After 6 months, RV-PA coupling index significantly improved in patients without residual PAH, from 0.96 ± 0.81 to 1.27 ± 1.24 mm/mm Hg (P = 0.02). Furthermore, RV load was markedly reduced, with sRVCPI falling from 691 ± 258 to 434 ± 217 mm Hg • mm, P < 0.01). However, in patients with residual PAH, RV-PA coupling index deteriorated from 0.64 ± 0.23 to 0.53 ± 0.12 mm/mm Hg (P < 0.01). As a result, RV overload was not significantly relieved (sRVCPI; from 971 ± 382 to 783 ± 166 mm Hg • mm, P = 0.22). In a multivariate analysis, baseline pulmonary vascular resistance (hazard ratio 1.009; P < 0.01) and preoperative sRVPCI (hazard ratio 1.003; P < 0.01) revealed to be independent predictors of residual PAH.

Conclusion

In terms of mechano-energetic function, preoperative "RV overwork" can be used as a robust predictor of an impaired RV-PA relationship in ASD patients. Moreover, periodic assessment of sRVPCI may contribute to the better management for patients with unrepaired ASD.

Abstract Figure.

An analysis of osteoporosis in patients with hereditary multiple exostoses

We analyzed osteoporosis in 20 HME patients. According to the T-score of BMD, 30% and 67.5% of the patients fell in the range of osteopenia in the lumbar spine and femoral neck. Our results indicate HME patients have low bone mass. They do not have abnormal bone metabolism.

INTRODUCTION

There are few reports of osteoporosis in hereditary multiple exostoses (HME) patients. Therefore, the purpose of this study was to analyze osteoporosis in HME patients.

METHODS

This retrospective cohort study included 20 patients diagnosed with HME. Patients underwent bone mineral density (BMD) measurement of the lumbar spine (n = 20) and femoral neck (n = 40). Bone metabolic parameters, including serum osteocalcin and urinary cross-linked N-telopeptide of type 1 collagen (NTx), were analyzed in all subjects. EXT1 and EXT2 genes were sequenced using genomic DNA. We also examined the correlation between genotype and BMD Z-score and T-score.

RESULTS

The mean BMD values of the lumbar spine were 1.085 ± 0.116 g/cm² (n = 11) in male and 1.108 ± 0.088 g/cm² (n = 9) in female. The mean BMD values of the femoral neck area were 0.759 ± 0.125 g/cm² (n = 22) in male and 0.749 ± 0.115 g/cm² (n = 18) in female. Z-score of most HME patients show < 0, indicating that these patients tend to have low bone mass compared with the age-matched population. According to the T-score of BMD, 30% (6 of 20) and 67.5% (27 of 40) of the patients fell in the range of osteopenia in the lumbar spine and femoral neck areas, respectively. Serum osteocalcin and urinary NTx were in the normal range in most patients. There was no significant correlation between genotypes and Z-score.

CONCLUSION

HME patients have low bone mass, especially in the femoral neck area. They do not have abnormal bone metabolism, and there was no correlation between genotypes and Z-score.

Caprylic acid enhances hydroxyhexylitaconic acid production in Aspergillus niger S17-5

AIM

Aspergillus niger S17-5 produces two alkylitaconic acids, 9-hydroxyhexylitaconic acid (9-HHIA) and 10-hydroxyhexylitaconic acid (10-HHIA), which have cytotoxic and polymer building block properties. In this study, we characterized the production of 9-HHIA and 10-HHIA by addition of their expected precursor, caprylic acid, to a culture of A. niger S17-5, and demonstrated batch fermentation of 9-HHIA and 10-HHIA in a jar fermenter with DO-stat.

METHODS AND RESULTS

Production titres of 9-HHIA and 10-HHIA from 3% glucose in a flask after 25 days cultivation were 0·35 and 1·01 g l^-1 respectively. Addition of 0·22 g l^-1 of caprylic acid to a suspension of resting cells of A. niger S17-5 led to 32% enhancement of total 9-HHIA and 10-HHIA production compared to no addition. No enhancement of the production of 9-HHIA or 10-HHIA by the addition of oxaloacetic acid was observed. Addition of caprylic acid to the culture at mid-growth phase was more suitable for 9-HHIA and 10-HHIA production due to less cell growth inhibition by caprylic acid. DO-stat batch fermentation with 3% glucose and 14·4 g l^-1 of caprylic acid in a 1·5 l jar fermenter resulted in the production titres of 9-HHIA and 10-HHIA being 0·48 and 1·54 g l^-1 respectively after 10 days of cultivation.

CONCLUSIONS

Addition of caprylic acid to the culture of A. niger S17-5 enhances 9-HHIA and 10-HHIA production.

SIGNIFICANCE AND IMPACT OF THE STUDY

These results suggest that 9-HHIA and 10-HHIA are synthesized with octanoyl-CoA derived from caprylic acid, and that the supply of octanoyl-CoA is a rate-limiting step in 9-HHIA and 10-HHIA production. To the best of our knowledge, this is the first report regarding the fermentation of naturally occurring itaconic acid derivatives in a jar fermenter.

Toll-like receptor 9 is a novel therapeutic target to prevent atrial fibrillation

Background

Atrial fibrillation (AF) is the most common type of arrhythmia seen in clinical practice. Recent studies suggest that inflammation contributes to the pathogenesis of AF. On the other hand, several evidence suggests that toll-like receptor (TLR) 9 recognizes bacterial DNA, activating innate immunity, whereas it also provokes inflammation in response to fragmented DNA released from mammalian cells. Recently, we have reported that TLR 9 plays a pivotal role in the development of vascular inflammation and atherogenesis through proinflammatory activation of macrophages.

Purpose

This study aimed to assess whether TLR9 contributes to the AF arrhythmogenesis.

Methods

TLR9 deficient (TLR9−/−) and wild-type mice were infused with angiotensin II (Ang II) or vehicle via an osmotic minipump for 4 weeks. Blood pressure and body weight were measured serially. Then, we examined AF inducibility by intracardiac electrophysiological study and the inflammation-induced atrial remodeling by biochemical analysis after 4 weeks of Ang II infusion.

Results

There was no significant difference in blood pressure and pulse rate between TLR9−/− and wild-type mice both before and after Ang II infusion. Ang II-treated TLR9−/− mice showed lower incidence of AF compared with wild-type mice treated with Ang II. Genetic deletion of TLR9 significantly reduced the interstitial fibrosis in atrium of Ang II-treated mice. TLR9−/− mice also showed less mRNA expressions of inflammatory and fibrosis-related biomarkers (TNF-α, interleukin-6, TGF-β, collagen-1, collagen-3) in atrium compared with wild-type mice.

Conclusions

TLR9 might contribute to the AF arrhythmogenesis associated with atrial inflammation. TLR9 might serve as a potential therapeutic target for AF.

Funding Acknowledgement

Type of funding source: None

Association between clinical risk factors and left ventricular function in patients with breast cancer following chemotherapy

Background

The sequential or concurrent use of two different types of agents such as anthracyclines and trastuzumab may increase myocardial injury and cancer therapeutics-related cardiac dysfunction (CTRCD), which is often the result of the combined detrimental effect of the two therapies for breast cancer patients. For risk stratification to detect the development of CTRCD, the current position paper from the European Society of Cardiology (ESC) lists several factors associated with risk of cardiotoxicity following treatment with chemotherapy. However, the association between clinical risk factors and left ventricular (LV) function in breast cancer patients is currently unclear.

Purpose

Our purpose was to investigate the impact of baseline risk factors on LV function in patients with preserved LV ejection fraction (LVEF) who have undergone anthracycline or trastuzumab chemotherapy for breast cancer.

Methods

We studied 86 breast cancer patients treated with anthracyclines, trastuzumab, or both. Mean age was 59±13 years and LVEF was 67±5%. In accordance with the current definition, CTRCD was defined as a decline in LVEF of &gt;10% to an absolute value of &lt;53% after chemotherapy. Based on the 2016 ESC position paper, clinical risk factors for CTRCD were defined as: (1) a cumulative total doxorubicin dose of ≥240 mg/m2, (2) age ≥65-year-old, (3) body mass index ≥30 kg/m2, (4) a previous history of radiation therapy to chest or mediastinum, (5) B-type natriuretic peptide ≥100pg/mL, (6) a previous history of cardiovascular disease, (7) atrial fibrillation, (8) hypertension, (9) diabetes mellitus, (10) current or ex-smoker.

Results

The relative decrease in LVEF after chemotherapy for patients with more than four risk factors was significantly greater than that for patients without (−9.3±10.8% vs. −2.2±10.2%; p=0.02). However, this finding did not apply to patients with more than one, two or three risk factors. Patients with more than four risk factors also tended to show a higher prevalence of CTRCD than those without (14.3% vs. 2.8%, p=0.12). Moreover, patients with more than four risk factors were more likely to have higher LV mass index (109.3±29.0 g/m2 vs. 83.2±21.0g /m2, p&lt;0.001), lower global longitudinal strain (18.4±2.8% vs. 20.0±2.6%, p=0.06) and higher E/e' (10.4 (8.9–13.0) vs. 9.0 (7.4–10.9), p=0.06) compared to those without.

Conclusions

Association between clinical risk factors and LV dysfunction following chemotherapy became stronger with an increase in the number of risk factors in breast cancer patients, and was especially strong for patients treated with chemotherapy who had more than four risk factors. Our findings can thus be expected to have clinical implications for better management of patients with breast cancer referred for chemotherapy.

Funding Acknowledgement

Type of funding source: None

Consideration of non-valvular atrial fibrillation with left atrial appendage thrombus formation despite under appropriate oral anticoagulation therapy

Background

Atrial fibrillation (AF) is the most frequently sustained cardiac arrhythmia, with a prevalence of about 2–3% in the general population. In accordance with CHADS2 or CHA2DS2-VASc score, appropriate oral anticoagulation therapy such as warfarin or direct oral anticoagulants (DOAC) significantly reduced the risk of thromboembolic events. However, left atrial (LA) thrombus can be detected in the LA appendage (LAA) in AF patients despite appropriate oral anticoagulation therapy.

Purpose

Our purpose was to investigate the associated factors of LAA thrombus formation in non-valvular atrial fibrillation (NVAF) patients despite under appropriate oral anticoagulation therapy.

Methods

We retrospectively studied consecutive 286 NVAF patients for scheduled catheter ablation or electrical cardioversion for AF in our institution between February 2017 and September 2019. Mean age was 67.1±9.4 years, 79 patients (29.5%) were female, and 140 (52.2%) were paroxysmal AF. All patients underwent transthoracic and transesophageal echocardiography before catheter ablation or electrical cardioversion. All patients received appropriate oral anticoagulation therapy including warfarin or DOAC for at least 3 weeks prior to transesophageal echocardiography based on the current guidelines. LAA thrombus was defined as an echodense intracavitary mass distinct from the underlying endocardium and not caused by pectinate muscles by at least three senior echocardiologists.

Results

Of 286 NVAF patients with under appropriate oral anticoagulation therapy, LAA thrombus was observed in 9 patients (3.3%). Univariate logistic regression analysis showed that age, paroxysmal AF, CHADS2 score ≥3, left ventricular end-diastolic volume index (LVEDVI), left ventricular ejection fraction (LVEF), left ventricular mass index (LVMI), LA volume index (LAVI), mitral inflow E and mitral e' annular velocities ratio (E/e'), and LAA flow were associated with LAA thrombus formation. It was noteworthy that multivariate logistic regression analysis showed that LAA flow was independent predictor of LAA thrombus (OR: 0.72, 95% CI: 0.59–0.89, p&lt;0.005) as well as LVEF. Furthermore, receiver operating characteristic (ROC) curve analysis identified the optimal cutoff value of LAA flow for predicting LAA thrombus as ≤15cm/s, with a sensitivity of 88%, specificity of 93%, and area under the curve (AUC) of 0.95.

Conclusions

LAA flow was strongly associated with LAA thrombus formation even in NVAF patients with appropriate oral anticoagulation therapy. According to our findings, further strengthen of oral anticoagulation therapy or percutaneous transcatheter closure of the LAA may be considered in NVAF patients with appropriate oral anticoagulation therapy but low LAA flow, especially &lt;15cm/s.

Funding Acknowledgement

Type of funding source: None

Frequency of cardiac arrhythmias in older adults: findings from the subclinical atrial fibrillation and risk of ischemic stroke (SAFARIS) study

Background

Prolonged monitoring of cardiac rhythm has been used in patients with symptomatic arrhythmias and to assess for atrial fibrillation (AF) after cryptogenic stroke, but not in the general population and especially in older adults.

Purpose

To evaluate the frequency of arrhythmias in a community-based cohort of older adults through 14-days continuous cardiac monitoring using a patch-based device.

Methods

Cardiac rhythm was analyzed in 533 participants free of AF and congestive heart failure (CHF) from the tri-ethnic (white, black, Hispanic) Subclinical Atrial Fibrillation and Risk of Ischemic Stroke (SAFARIS) study. AF, supraventricular tachycardia (SVT, defined as 4 beats or more), premature atrial (PACs) and ventricular (PVCs) contractions, ventricular tachycardia (VT, defined as 4 beats or more), sinus pauses (SP) and atrio-ventricular blocks (AVB) were analyzed. Gender, age and race-ethnic differences were examined.

Results

Mean age was 77.2±6.8 years (198 men, 335 women). Recording duration was over 10 days in 91%, and over 13 days in 84%. AF was present in 10 participants (1.9%), atrial flutter in 1 (0.2%). Other arrhythmias are reported in the Table. SP (1.9%) and high-degree AVB (Mobitz II: 0.6%; 3rd degree: 0.9%) were rare. No significant race-ethnic differences were observed.

Conclusion

In older adults without history of stroke or CHF, prolonged rhythm monitoring revealed moderate frequency of AF, but higher than expected frequencies of AF-predisposing conditions such as SVT and frequent PACs. VT episodes were relatively frequent, whereas SP and AVB were less frequent than commonly believed. Most arrhythmias were more frequent in the oldest; ventricular arrhythmias were more common in men than in women.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): NINDS R01 NS083874

Positive effect of dapagliflozin on left ventricular longitudinal function for type 2 diabetic mellitus patients with chronic heart failure

Background

Type 2 diabetes mellitus (T2DM) has come to be considered an independent predictor of mortality, and also a contributor to the development of heart failure (HF) with reduced ejection fraction (HFrEF) and with preserved ejection fraction (HFpEF). Left ventricular (LV) longitudinal myocardial dysfunction as assessed in terms of lower global longitudinal strain (GLS), has been identified even in T2DM patients with preserved LV ejection fraction (LVEF), and should be considered the first marker of a preclinical form of DM-related cardiac dysfunction, leading to HFpEF. Sodium glucose cotransporter type 2 (SGLT2) inhibitors represent a new class of anti-hyperglycemic agents for T2DM, but the effect of SGLT2 inhibitors on LV longitudinal myocardial function in T2DM patients with HF remains uncertain. To examine this effect, as well as the association of LV longitudinal myocardial function with LV diastolic function after administration of SGLT2 inhibitor in T2DM patients with stable HF, we analyzed data from our previous prospective multicenter study, in which we investigated the effect of SGLT2 inhibitor on LV diastolic functional parameters of T2DM patients with stable HF at five institutions in Japan.

Methods

Our previous trial was a prospective multicenter study of 58 T2DM patients with stable HF at five institutions in Japan. Patients who had been taking at least one antidiabetic drugs other than SGLT2 inhibitors started the administration of 5 mg/day of dapagliflozin. Echocardiography was performed at baseline and 6 months after administration of dapagliflozin. LV diastolic function was defined as the ratio of mitral inflow E to mitral e' annular velocities (E/e'). LV longitudinal myocardial function was assessed as GLS based on the current guidelines.

Results

E/e' significantly decreased from 9.3 to 8.5 cm/s 6 months after administration of dapagliflozin (p=0.020) as previously described, while GLS showed significant improvement from 15.5±3.5% to 16.9±4.1% (p&lt;0.01) 6 months after administration of dapagliflozin. Furthermore, improvement of GLS in HFpEF patients was more significant from 17.0±1.9% to 18.7±2.0% (p&lt;0.001), compared to that in HFrEF patients from 11.3±3.8% to 11.8±4.6% (p=0.13). It was noteworthy that multiple regression analysis showed that the change in GLS after administration of dapagliflozin was the only independent determinant parameter for the change in E/e' after administration of dapagliflozin.

Conclusion

Dapagliflozin was found to be associated with improvement of LV longitudinal myocardial function, which led to further improvement of LV diastolic function of T2DM patients with stable HF. GLS-guided management may thus lead to improved management of T2DM patients with stable HF.

Representative case

Funding Acknowledgement

Type of funding source: None

Heparan sulfate deficiency leads to hypertrophic chondrocytes by increasing bone morphogenetic protein signaling

OBJECTIVE

Exostosin-1 (EXT1) and EXT2 are the major genetic etiologies of multiple hereditary exostoses and are essential for heparan sulfate (HS) biosynthesis. Previous studies investigating HS in several mouse models of multiple hereditary exostoses have reported that aberrant bone morphogenetic protein (BMP) signaling promotes osteochondroma formation in Ext1-deficient mice. This study examined the mechanism underlying the effects of HS deficiency on BMP/Smad signaling in articular cartilage in a cartilage-specific Ext^-/- mouse model.

METHOD

We generated mice with a conditional Ext1 knockout in cartilage tissue (Ext1-cKO mice) using Prg4-Cre transgenic mice. Structural cartilage alterations were histologically evaluated and phospho-Smad1/5/9 (pSmad1/5/9) expression in mouse chondrocytes was analyzed. The effect of pharmacological intervention of BMP signaling using a specific inhibitor was assessed in the articular cartilage of Ext1-cKO mice.

RESULTS

Hypertrophic chondrocytes were significantly more abundant (P = 0.021) and cartilage thickness was greater in Ext1-cKO mice at 3 months postnatal than in control littermates (P = 0.036 for femur; and P < 0.001 for tibia). However, osteoarthritis did not spontaneously occur before the 1-year follow-up. matrix metalloproteinase (MMP)-13 and adamalysin-like metalloproteinases with thrombospondin motifs(ADAMTS)-5 were upregulated in hypertrophic chondrocytes of transgenic mice. Immunostaining and western blotting revealed that pSmad1/5/9-positive chondrocytes were more abundant in the articular cartilage of Ext1-cKO mice than in control littermates. Furthermore, the BMP inhibitor significantly decreased the number of hypertrophic chondrocytes in Ext1-cKO mice (P = 0.007).

CONCLUSIONS

HS deficiency in articular chondrocytes causes chondrocyte hypertrophy, wherein upregulated BMP/Smad signaling partially contributes to this phenotype. HS might play an important role in maintaining the cartilaginous matrix by regulating BMP signaling.

The potential of a surface pre-reacted glass root canal dressing for treating apical periodontitis in rats

AIM

To evaluate the efficacy of a prototype root canal dressing containing surface pre-reacted glass-ionomer (S-PRG) fillers on repairing induced periapical lesions in a rat model. Calcium hydroxide [Ca(OH)₂ ] was applied as a comparison in the healing process.

METHODOLOGY

The pulp chambers of the maxillary first molars in 64 male Wistar rats aged 16 weeks were opened to induce periapical lesions. After 28 days, the mesial canal of each tooth was prepared, irrigated with 2.5% sodium hypochlorite only (control group: irrigation) or followed by the respective dressing [Ca(OH)₂ group, irrigation + Ca(OH)₂ ; S-PRG group, irrigation + S-PRG] and restored with composite resin for 3 or 7 days (10/group). Four rats with healthy molars were used as blank controls. Descriptive analysis of the periapical radiographs, haematoxylin and eosin staining and immunohistochemical observation was performed 3 and 7 days after treatment. The periapical grey value, CD68 macrophages and osteoclasts (cathepsin-K) were quantified and statistically analysed with Tukey's honest significant difference test. A significant difference was achieved when P values were <0.05.

RESULTS

S-PRG and Ca(OH)₂ dressings were associated with increased periapical grey values and inhibited osteoclast activity at 3 and 7 days; a significant difference in radiographic results and the number of osteoclasts was obtained at 3 and 7 days compared with the control group (P < 0.05). Reparative tissue was observed histologically in the space of the periapical resorbed necrotic area after S-PRG and Ca(OH)₂ treatment for 3 and 7 days. The number of macrophages was significantly decreased at 3 and 7 days in the S-PRG and Ca(OH)₂ specimens when compared with the controls (P < 0.05).

CONCLUSIONS

In a rat experimental model, the S-PRG root canal dressing was comparable to Ca(OH)₂ in promoting the healing of experimentally induced periapical lesions. S-PRG paste has the potential to be used as an alternative intracanal dressing in teeth with apical periodontitis.

Nivolumab treatment beyond progressive disease in advanced non-small cell lung cancer

PURPOSE

This study evaluated the efficacy and safety of nivolumab treatment beyond progressive disease (PD) in non-small cell lung cancer (NSCLC).

PATIENTS/METHODS

Medical records of consecutive patients with advanced NSCLC who received nivolumab between December 2015 and December 2018 were reviewed. Clinical outcomes of three groups of eligible patients who received nivolumab as a second-line treatment after PD were compared based on Response Evaluation Criteria in Solid Tumors v1.1. We conducted subgroup analyses in patients with and without new lesions at first PD.

RESULTS

Twenty-eight patients continued nivolumab treatment beyond PD (TBP). Post PD, 46 patients switched to other anti-cancer treatment (OAT), and 21 received no further anti-cancer treatment (NAT). There were no significant differences in overall survival (OS) or survival post progression (SPP) between TBP and OAT groups (OS: 15.6 vs. 13.4 months, P = .40, SPP: 12.2 vs. 9.3 months, P = .42). Subgroup analyses indicated that among patients without new lesions at first PD, SPP was longer in the TBP than in the OAT groups (12.6 vs. 9.3 months, P = .22, HR: 0.64; 95% CI 0.31‒1.31). The frequency of immune-related adverse events leading to discontinuation during nivolumab beyond PD was equivalent to that for pre-PD (10.7 vs. 12.6%).

CONCLUSIONS

No significant benefits were associated with continuation of nivolumab for advanced NSCLC patients. Continuation of nivolumab beyond PD could be a more useful option in patients without new lesions at first PD. Treatment-related toxicities require attention during nivolumab treatment not only before PD but also beyond PD.

P1050General anesthesia improved rate of first-pass pulmonary vein isolation by radiofrequency ablation in patients with atrial fibrillation

Background

Pulmonary vein isolation (PVI) with radiofrequency ablation (RFA) is one of the important procedures for atrial fibrillation (AF). Attaining the stability of RFA, respiratory management and pain control during the procedure are required.

Purpose

We compared the characteristic parameters and procedural outcomes between general anesthesia and moderate (conscious) sedation in patients with AF performed RFA.

Methods

We performed a retrospective, 2-center observational study to compare the general anesthesia with moderate sedation during RFA on AF from January 2018 until December 2018. In general anesthesia group, we administrated propofol and muscle relaxants under mechanical ventilation. In moderate sedation group, we administrated dexmedetomidine and/or propofol with analgesic drug. Procedural time of AF ablation, first-pass PVI (pulmonary vein isolation after completing the right or left circle) were assessed.

Results

A total of 98 patients with mean age 66 ± 11 years were enrolled (80 males, 81%). Of these, 19 patients were performed RFA under general anesthesia and 79 patients were performed under moderate sedation. Age, gender, BMI, medications before admission and CHADs2 score (general anesthesia:1.9 ± 1.2 vs moderate sedation:1.5 ± 1.1, p = 0.14), left atrium diameter (40.2 ± 6.2 vs 40.6 ± 6.8 mm, p = 0.81) and proportion of paroxysmal AF (47.4 vs 54.4%, p = 0.61) were similar between two groups. Our study found catheter RFA with general anesthesia to be associated with reduced procedural time (161 ± 29 vs 241 ± 58 minutes, p &lt; 0.01) and improved the rate of first-pass PVI (left pulmonary vein: 84.2 vs 59.5%, p = 0.06 and right pulmonary vein: 84.2 vs 58.2%, p =0.04).

Conclusions

RFA under general anesthesia improved first-pass PVI (quality of PVI) and shortened procedural time. General anesthesia may attribute to attaining the catheter and patient stability during RFA for PVI.