Association of beta blocker use with new-onset heart failure and mortality in atrial fibrillation without pre-existing heart failure: the Fushimi AF registry

Background

Heart failure (HF) is one of the major complications in atrial fibrillation (AF). We previously reported that not a few AF patients without pre-existing HF (defined as prior HF hospitalization, New York Heart Association functional class≥2, or left ventricular ejection fraction (LVEF)<40%) subsequently developed new-onset HF. Beta blockers are the established therapy for HF, but it remains unclear whether beta blockers prevent new-onset HF and improve outcomes in AF patients without preexisting HF.

Methods

In the Fushimi AF registry, 778 of 3,262 patients without pre-existing HF were receiving beta blockers at baseline. We investigated the incidence of new-onset HF defined as cardiac death or HF hospitalization, and all-cause death in a propensity-matched cohort (N=1,198; mean age, 71 years; 39% female; mean LVEF, 66%). Additionally, annual follow-up prescription data before the onset of events were collected in 294 of patients with beta blockers and 395 of those without beta blockers. We also investigated the association of starting or stopping beta blockers with the incidence of new-onset HF and all-cause death.

Results

During the median follow-up of 5.8 years, new-onset HF and all-cause death occurred in 77 (12.9%) and 118 (19.7%) of patients with beta blockers, and 70 (11.7%) and 131 (21.9%) of those without beta blockers, respectively. Incidence of new-onset HF was comparable between patients with and without beta blockers (Figure 1), and incidence of all-cause death was also comparable between the two groups (Figure 2). In exploratory subgroup analyses, there was no interaction in the association of beta blockers with the incidence of events, except for pulse rate for new-onset HF and left atrial size for all-cause death. Hazard ratio of beta blockers for new-onset HF tended to be lower in patients with higher pulse rates (>84 bpm) (Figure 1), and that for all-cause death was lower in those without left atrial enlargement (Figure 2). Of patients with follow-up prescription data, beta blockers were stopped in 55 (18.7%) and started in 97 (24.6%) patients, respectively. Patients with starting beta blockers had higher pulse rate (78.5±17.3 vs 74.9±13.9 bpm; p=0.03) and more symptomatic AF (58.8% vs 46.0%; p=0.03) compared to those without starting beta blockers, while there was no difference in baseline characteristics between those with and without stopping beta blockers. During the follow-up, the incidences of new-onset HF and all-cause death were also comparable between the patients with and without stopping beta blockers and those with and without starting beta blockers.

Conclusion

Beta blockers were not associated with the incidence of new-onset HF and all-cause death in AF patients without pre-existing HF. However, the exploratory subgroup analyses suggested the existence of subjects who may benefit from beta blockers.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Boehringer Ingelheim, Bayer Healthcare, Pfizer, Bristol-Myers Squibb, Astellas Pharma, AstraZeneca, Daiichi Sankyo, Novartis Pharma, MSD, Sanofi-Aventis, and Takeda Pharmaceutical.

Clinical characteristics and outcomes of atrial fibrillation patients with peripheral artery disease: the Fushimi AF Registry

Background

Atrial fibrillation (AF) represents the common arrhythmia and increases the risk of thromboembolism. Risk assessment for thromboembolism is important for the management of AF patients. Peripheral artery disease (PAD) is identified as a risk factor for thromboembolism in CHA2DS2-VASc score. However, there are little data on clinical characteristics and cardiovascular events of AF patients with PAD.

Purpose

In this study, we investigated the clinical characteristics and outcomes of AF patients with PAD.

Methods

The Fushimi AF Registry, a community-based prospective survey, was designed to enroll all of the AF patients who visited the participating medical institutions in Fushimi-ku, Kyoto, Japan. The inclusion criterion of the registry is the documentation of AF at 12-lead electrocardiogram or Holter monitoring at any time, and there are no exclusion criteria. We started to enroll patients from March 2011 and follow up data including prescription status were available in 4,464 patients from March 2011 to August 2021. Median follow-up period was 1,848 days.

Results

Of 4,464 patients, 183 patients had PAD (4.1%; PAD group). The mean age was higher in PAD group than no-PAD group (PAD group vs. no-PAD group: 76.7 vs. 73.5; p<0.01). Patients with PAD had more co-morbidities such as stroke, systemic embolism, congestive heart failure, hypertension, diabetes mellitus, dyslipidemia coronary artery disease and chronic kidney disease than those without PAD. Thus, CHADS2 score, CHA2DS2-VASc score and HAS-BLED score were higher in PAD group than no-PAD group (2.81 vs. 2.00; p<0.01, 5.17 vs. 3.30; p<0.01, 2.42 vs. 1.71; p<0.01, respectively). The proportion of patients with oral anticoagulant was similar between the two groups and the proportion of patients with antiplatelet drug was higher in PAD group than no-PAD group (59.0% vs. 55.6%; p=0.36, 62.9% vs. 24.7%; p<0.01, respectively). The incidences of all-cause death, cardiac death and myocardial infarction were higher in PAD group than no-PAD group (11.4 vs. 4.6 per 100 person-years; log-rank p<0.01, 1.7 vs. 0.8 per 100 person-years; log-rank p<0.01, 1.2 vs. 0.2 per 100 person-years; log-rank p<0.01). However, the incidence of stroke or systemic embolism was similar between the two groups (2.9 vs. 2.2 per 100 person-years, log-rank p=0.19). Finally, the incidence of composite of cardiac death, stroke, systemic embolism or myocardial infarction was higher in PAD group than no-PAD group (6.0 vs. 3.0 per 100 person-years; log-rank p<0.01).

Conclusion

AF patients with PAD had significantly higher risk for death and cardiac events, whereas the incidence of thromboembolism was similar between AF patients with and without PAD.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Japan Agency for Medical Research and Development

Association of cardiothoracic ratio with heart failure hospitalization in patients with atrial fibrillation: the Fushimi AF Registry

Background

Chest radiography is the most common diagnostic imaging test in clinical medicine, and the cardiothoracic ratio (CTR) is a readily available and non-invasive tool with which to assess the volume status and cardiomegaly. However, it remains unknown whether CTR on chest radiography is associated with the incidence of HF hospitalization in AF patients remains unclear.

Methods

The Fushimi AF Registry is a community-based prospective survey of AF patients in Fushimi-ku, Kyoto, Japan. The inclusion criterion of the registry is the documentation of AF at 12-lead electrocardiogram or Holter monitoring at any time, and there are no exclusion criteria. We started to enroll patients from March 2011, and follow-up data were available for 4,489 patients by the end of August 2021. In the present study, 3,727 patients with available data of CTR were examined. We divided the patients into two groups according to their CTR at baseline; Higher group (CTR ≥50.0%, n=2,696) and Lower group (CTR <50.0%, n=1,031), and compared the clinical background and outcomes between the two groups.

Results

The proportion of female was grater in Higher group, and the patients in Higher group were older. The patients in Higher group had higher prevalence of HF, hypertension and chronic kidney disease. During the median follow-up of 3,033 days, in Kaplan-Meier analysis, the incidence rates of HF hospitalization were higher in Higher group (Higher group: 2.5% per person-year vs. Lower group: 1.1%; p<0.01). Multivariate Cox proportional hazards regression analysis revealed that higher CTR (≥50.0%) was an independent determinant of the incidence of HF hospitalization. Furthermore, when we divided the patients into four groups based on the quartile of CTR; Q1 (CTR<49.0%), Q2 (49.0≤CTR<53.8%), Q3 (53.8≤CTR<59.0%), Q4 (59.0%≤CTR), the incidence of HF hospitalization was more frequent in patients with higher CTR, regardless of the presence or absence of prior hospitalization for HF (Figure).

Conclusion

In Japanese AF patients, patients with higher CTR had significantly higher incidence of HF hospitalization, regardless of the prevalence of prior hospitalization for HF.

Funding Acknowledgement

Type of funding sources: None.

The association of left ventricular ejection fraction with incident heart failure in patients with atrial fibrillation

Background

Atrial fibrillation (AF) increases the risk of incident heart failure (HF). Left ventricular ejection fraction (LVEF) is an important prognostic parameter in patients with HF. However, little is known regarding the association of LVEF with incident HF in patients with AF.

Purpose

The aim of this study is to investigate the relationship between LVEF at enrollment and incidence of HF hospitalization during follow-up period in patients with AF.

Methods

The Fushimi AF Registry is a community-based prospective survey of patients with AF in Fushimi-ku, Kyoto, Japan. The inclusion criterion of the registry is the documentation of AF at 12-lead electrocardiogram or Holter monitoring at any time, and there are no exclusion criteria. We started to enroll patients from March 2011, and follow-up data were available for 4,489 patients by the end of August 2021. In the present study, we investigated 3,544 patients with the data of LVEF at enrollment. We divided the patients into 4 groups stratified by LVEF (reduced LVEF [LVEF <40%], mildly reduced LVEF [LVEF: 40–49%], slightly reduced LVEF [LVEF: 50–59%], and normal LVEF [LVEF ≥60%]), and compared the backgrounds and outcomes between these 4 groups.

Results

Of 3,544 patients, the mean age was 73.6±10.7 years, 1,420 (40%) were female, 1,781 (50%) were paroxysmal AF, and 1,085 (30%) had pre-existing HF. The mean CHADS2 and CHA2DS2-VASc scores were 2.1±1.3 and 3.4±1.7, respectively. The mean LVEF at enrollment was 63±12% (reduced LVEF: 197 [6%], mildly reduced LVEF: 250 [7%], slightly reduced LVEF: 532 [15%] and normal LVEF: 2,565 [72%], respectively). Patients with lower LVEF demonstrated lower prevalence of female and paroxysmal AF, and had a higher CHADS2 and CHA2DS2-VASc scores (all P<0.01). A total of 605 patients were hospitalized for HF during the median follow-up period of 5.5 years, corresponding to an annual incidence of 3.4% per person-year. Kaplan-Meier curves demonstrated that LVEF at enrollment could stratify the incidence of HF hospitalization during follow-up in patients with AF (Picture 1). Multivariable Cox regression analysis revealed that lower LVEF strata were significantly associated with the increased risk of HF hospitalization even after adjustment by age, sex, type of AF and CHA2DS2-VASc score (Picture 1). An increased risk of HF hospitalization was observed even in patients with mildly reduced LVEF (adjusted hazard ratio: 2.56, 95% CI: 1.99–3.29) as well as in those with slightly reduced LVEF (adjusted hazard ratio: 1.79, 95% CI: 1.45–2.22) compared with those with normal LVEF. These results were also the case in AF patients without pre-existing HF (Picture 2).

Conclusion

LVEF at enrollment could stratify the incidence of HF hospitalization in patients with AF, suggesting the importance of measuring LVEF in all patients with AF. Even mildly (LVEF: 40–49%) or slightly (LVEF: 50–59%) reduced LVEF was independently associated with the risk of incident HF in patients with AF.

Funding Acknowledgement

Type of funding sources: None.

Impact of catheter ablation on functional tricuspid regurgitation in patients with atrial fibrillation

Background

Since atrial functional tricuspid regurgitation (AF-TR) is associated with increased heart failure and mortality, the management of AF-TR is clinically important. Atrial fibrillation (AF) plays the main role in AF-TR. However, the effectiveness of catheter ablation (CA) and mechanism of improvement of AF-TR haven't been fully evaluated.

Purpose

We sought to investigate the impact of CA for AF on AF-TR in patients with moderate or more TR.

Methods

We retrospectively investigated consecutive 2685 patients with AF who received CA from February 2004 to December 2019 in Japan. The current study population consisted of 102 patients with moderate or greater TR who underwent CA for AF. The echocardiographic parameters were compared between pre-ablation and post-ablation transthoracic echocardiography (TTE), and the recurrence rate of AF/ atrial tachycardia (AT) was measured.

Results

The mean age was 73.2 years, 53% were women. TR severity and TR jet area significantly improved after CA for AF (TR jet area: 5.8 [3.9–7.6] cm2 to 2.0 [1.1–3.0] cm2, p<0.001). In addition, mitral regurgitation (MR) jet area, left atrial (LA) area, mitral valve diameter, right ventricular (RV) end-diastolic area, right atrial (RA) area, tricuspid valve (TV) diameter decreased after CA (p<0.001, <0.001, <0.001, = 0.02, <0.001, and <0.001, respectively). There was no significant difference between one-year recurrence of AF/AT and TR severity at pre-ablation TTE (moderate 28.6%, moderate to severe 37.2%, and severe 31.6%, p=0.72).

Conclusions

TR severity and jet area improved after CA in patients with AF and moderate or more TR. RV size, RA size, TV diameter also decreased after CA, which may be associated with TR improvement. There was no significant difference between one-year recurrence of AF/AT and TR severity at pre-ablation TTE.

Funding Acknowledgement

Type of funding sources: None.

10-year clinical outcomes after radiofrequency catheter ablation for atrial fibrillation. A single center experience

Background

Radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) is becoming a routine procedure to treat patients with drug-refractory symptomatic AF. However, data regarding very long-term clinical outcomes is limited. The aim of the present study was to evaluate the 10-year clinical outcomes of patients who underwent RFCA for paroxysmal and persistent AF.

Methods

We retrospectively enrolled 503 consecutive patients (mean age 66,9±9,51 years; 71,6% male) who underwent RFCA for drug-refractory symptomatic AF between February 2004 and June 2011. Follow-up information was obtained using medical records and/or telephonic interviews with the patient, relatives and/or referring physicians.

Results

Among 503 patients enrolled in this study, 362 had paroxysmal atrial fibrillation (PAF) and 141 had persistent atrial fibrillation (PeAF) (72% and 28%, respectively). Mean follow-up was 8,84±3,05 years. The 10-year event-free rate for recurrent atrial tachyarrhythmia (AT) after the first procedure was 44,5% (49,4% for PAF vs 31,9% for PeAF; p=0,002 by log-rank test) and 81,9% after the last procedure (87,3% for PAF and 67,9% for PeAF; p≤0,001 by log-rank test). AT recurrence was observed most commonly during the first 12 months of the initial procedure (56%), with only 18% of them occurring after 60 months. Multivariate analysis revealed that persistent AF (hazard ratio=1,366; 95% confidence interval 1,058–1,76; p=0,017) and duration of AF >5 years (hazard ratio=1,357; 95% confidence interval 1,064–1,732; p=0,005) were independent risk factors for AT recurrence. Regarding adverse events, there were 24 (4,8%) hospitalizations for acute decompensated heart failure, 20 (4%) ischemic strokes and 14 (2,8%) bleeding complications requiring hospital admissions. Patients taking oral anticoagulation and antiarrhythmic drugs at the end of the study accounted for 32,8% and 16,7% respectively.

Conclusions

RFCA for AF provided favorable results in terms of arrhythmia event-free survival in long-term follow-up with better results in patients with paroxysmal AF. Persistent AF and long-standing AF (beyond 5 years) were associated with AT recurrence. Despite the large number of patients who discontinued oral anticoagulation, thromboembolic adverse events were rare.

Funding Acknowledgement

Type of funding sources: None.

Sex differences and arrhythmia recurrence after catheter ablation for atrial fibrillation

Background

Several previous studies reported female sex is associated with high recurrence rate of atrial tachyarrhythmia (ATA) after catheter ablation (CA) for atrial fibrillation (AF).

Purpose

We investigated the relationship between sex differences and recurrence rate of ATA after CA for AF in a large single-center database.

Methods

We enrolled consecutive 2033 patients undergoing first time CA for AF in our institution between Feb.2004 and Dec. 2017.

We compared the long-term outcomes between female (N=603) and male (N=1430).

Results

Female patients were older (70.8 vs. 66.3, p<0.0001), and had lower prevalence of persistent AF (23.1% vs. 33.5%, p<0.0001). Also, left atrial dimension was smaller (40.0 vs. 41.1, p=0.0005). and prior antiarrhythmic drug use was more prevalent (38.2% vs. 28.7%, p<0.0001) in female patients.

Ablation method for pulmonary vein isolation (PVI) was radiofrequency catheter ablation in 1634 patients (80.4%) and cryoballoon ablation in 399 (20.6%).

Median follow-up duration was 1342±115 days. The 3-year ATA recurrence rate after first CA was 35.8% overall: 39.9% in female and 34.2% in male (Log-rank P=0.01).

A multivariate analysis revealed that the factors associated with higher ATA recurrence rate were female (p=0.01), persistent AF (p=0.006), and larger left atrial dimension (p=0.007).

Conclusions

Female gender is an independent predictor of arrhythmia recurrence after CA for AF.

Funding Acknowledgement

Type of funding source: None

The impact of catheter ablation for patients with asymptomatic atrial fibrillation: subanalysis of kansai plus atrial fibrillation (kpaf) registry

Background

Catheter ablation (CA) of atrial fibrillation (AF) for symptomatic patients improves the quality of life and prognosis of patients with heart failure. However, the impact of CA for asymptomatic patients is still controversial.

Purpose

We aimed to investigate the clinical outcomes of CA of AF for asymptomatic patients compared to those for symptomatic patients.

Methods

A total of 5,013 patients from the Kansai Plus Atrial Fibrillation (KPAF) Registry who underwent CA were screened. The patients were divided into three groups by type of AF; paroxysmal (PAF), persistent (PEAF) and long standing (LSAF) and the patients in each type of AF were divided into two groups: asymptomatic and symptomatic. The primary endpoint was recurrent supraventricular tachyarrhythmias lasting for more than 30 seconds during follow-up 4 years after CA. The secondary endpoint was a composite of cardiovascular, cerebral, and gastrointestinal events during follow-up 4 years after CA. The incidence of complications related to CA between asymptomatic and symptomatic patients was also evaluated. Kaplan–Meier analysis was employed to estimate the primary and secondary endpoints. The statistical differences in primary and secondary endpoints between asymptomatic and symptomatic patients were evaluated using a log–rank test. The impact of symptom due to AF on the primary and secondary endpoint was evaluated using a Cox hazard analysis. The difference in incidence of complications between asymptomatic and symptomatic patients was evaluated using a chi–square test.

Results

In this study population, PAF was the most frequent at 64.4%, followed by PEAF (22.7%) and LSAF (13.0%). There were some significant differences in the baseline characteristics between asymptomatic and symptomatic patients in each type of AF. The proportion of male was significantly higher in asymptomatic patients than symptomatic patients in PAF (81.2% versus 67.2%, p<0.001) and PEAF (86.4% versus 74.3%, p<0.001). Left atrial diameter was larger in asymptomatic patients than symptomatic patients only in PAF (40±6mm versus 38±6mm, p<0.001). In all types of AF, there was no significant difference in primary endpoint between asymptomatic and symptomatic patients as follows: 37.5% versus 40.6% (p=0.6) in PAF, 45.2% versus 55.1% (p=0.09) in PEAF and 59.3% versus 63.6% (p=1.0) in LSAF. There was also no significant difference in secondary endpoint between asymptomatic and symptomatic patients: 7.1% versus 6.8% (p=0.7) in PAF, 5.4% versus 8.7% (p=0.3) in PEAF and 4.4% versus 5.1% (p=0.5) in LSAF. In a Cox hazard analysis, the symptom did not affect both of the primary and secondary endpoints in each type of AF. In regard to the incidence of complications related to CA, there was no significant difference between asymptomatic and symptomatic patients in each type of AF.

Conclusion

CA of AF for asymptomatic patients can be safe and can lead to equivalent outcomes as well as symptomatic patients.

Funding Acknowledgement

Type of funding source: None

P178 Sinus rhythm restoration by catheter ablation improved cognitive function in elderly patients with atrial fibrillation

Background

Atrial fibrillation (AF) may cause cognitive impairment. However, the impact of sinus rhythm (SR) restoration by catheter ablation on the improvement of cognitive function remains to be elucidated.

Methods

A total of 57 consecutive elderly patients (70.8 ± 4.8 years old) who underwent catheter ablation for AF were prospectively enrolled. The change of cognitive function for 6 months was compared between patients with SR restoration (at least 3 months; n = 49) and patients with AF recurrence (n = 8). Cognitive function was evaluated by the mini-mental state examination (MMSE).

Results

There was no significant difference in baseline characteristics between the 2 groups, including MMSE score (27.3 ± 2.6 vs. 27.6 ± 1.5 points; p = 0.793). The change of MMSE score was significantly greater in patients with SR restoration than those with AF recurrence (0.28 ± 0.70 vs. − 0.50 ± 0.75 points; p = 0.006; Figure). The general liner modeling revealed that SR restoration (effect estimate, 0.369; 95% confidence interval, 0.110 to 0.627; p = 0.006) was independently associated with the change of MMSE score.

Conclusion

In elderly AF patients, successful restoration of SR by catheter ablation was associated with the improvement of cognitive function.

Abstract P178 Figure

P985The long-term impact of maintaining sinus rhythm on the risk for death or heart failure after catheter ablation for atrial fibrillation in a real world clinical practice

Background

Catheter ablation has been rapidly spread as a first line therapy for atrial fibrillation (AF). A recent randomized trial have shown that AF ablation reduces the risk of death or hospitalization for heart failure (HF). However, the impact of maintained sinus rhythm (SR) on long-term risk of death or HF hospitalization has not been adequately evaluated.

Purpose

To investigate the impact of maintaining SR by AF ablation on long-term risk of all-cause death or HF hospitalization.

Methods

The long-term clinical outcomes were compared between patients with maintained SR and those with recurrent AF using a landmark analysis in which the landmark point was set at 1.5-year after the 1st ablation.

Results

Among consecutive 1467 patients who underwent AF ablation in our institution between February 2004 and December 2017, the study population consisted of 1311 patients after excluding 150 patients because of death or lost to follow-up. Mean age was 67.9±0.3 and paroxysmal AF was 67%. Among 460 patients who had AF recurrence within 1.5 years after the 1st ablation, 328 underwent 2nd ablation. Therefore, at 1.5-year after the 1st AF ablation, 1145 patients had maintained SR rhythm (SR-group), and 166 patients had recurrent AF episodes (AF-group). During 4.7±2.4 years of follow-up, the cumulative 5-year incidence of death or HF beyond 1.5 years after the 1st ablation was 5.1% in SR-group and 15.6% in AF-group (log rank P<0.001). After adjusting for baseline confounders, the lower risk of SR-group relative to AF-group for death or HF was still statistically significant (HR: 2.05, 95% CI: 1.11–3.58, P=0.02).

Risks for a Composite of Death or HF Hazard Ratio (95% CI) Crude HR P value Adjusted HR P value AF recurrence 2.59 (1.43–4.43) 0.002 2.05 (1.11–3.58) 0.02 Age>75 years old 2.55 (1.56–4.10) <0.001 2.32 (1.39–3.81) 0.002 Female 0.85 (0.49–1.43) 0.56 0.73 (0.40–1.25) 0.26 PeAF 1.25 (0.68–2.16) 0.45 0.98 (0.52–1.75) 0.94 LSAF 1.10 (0.46–2.23) 0.82 0.70 (0.28–1.53) 0.39 LVEF>50% 0.27 (0.16–0.48) <0.001 0.57 (0.31–1.09) 0.09 Past history of HF 7.06 (4.18–11.6) <0.001 4.67 (2.51–8.41) <0.001 CKD 4.74 (2.08–9.39) <0.001 2.23 (0.94–4.69) 0.07 AF, Atrial fibrillation; PeAF, Persistent AF; LSAF; Long standing AF; HF, Heart failure; CKD, Chronic kidney disease.

Figure 1

Conclusions

Successfully maintained SR was associated with reduced long-term risk for death or HF hospitalization in real world patients undergoing AF ablation.

Angiopoietin-like protein 2 promotes chondrogenic differentiation during bone growth as a cartilage matrix factor

OBJECTIVE

Chondrocyte differentiation is crucial for long bone growth. Many cartilage extracellular matrix (ECM) proteins reportedly contribute to chondrocyte differentiation, indicating that mechanisms underlying chondrocyte differentiation are likely more complex than previously appreciated. Angiopoietin-like protein 2 (ANGPTL2) is a secreted factor normally abundantly produced in mesenchymal lineage cells such as adipocytes and fibroblasts, but its loss contributes to the pathogenesis of lifestyle- or aging-related diseases. However, the function of ANGPTL2 in chondrocytes, which are also differentiated from mesenchymal stem cells, remains unclear. Here, we investigate whether ANGPTL2 is expressed in or functions in chondrocytes.

METHODS

First, we evaluated Angptl2 expression during chondrocyte differentiation using chondrogenic ATDC5 cells and wild-type epiphyseal cartilage of newborn mice. We next assessed ANGPTL2 function in chondrogenic differentiation and associated signaling using Angptl2 knockdown ATDC5 cells and Angptl2 knockout mice.

RESULTS

ANGPTL2 is expressed in chondrocytes, particularly those located in resting and proliferative zones, and accumulates in ECM surrounding chondrocytes. Interestingly, long bone growth was retarded in Angptl2 knockout mice from neonatal to adult stages via attenuation of chondrocyte differentiation. Both in vivo and in vitro experiments show that changes in ANGPTL2 expression can also alter p38 mitogen-activated protein kinase (MAPK) activity mediated by integrin α5β1.

CONCLUSION

ANGPTL2 contributes to chondrocyte differentiation and subsequent endochondral ossification through α5β1 integrin and p38 MAPK signaling during bone growth. Our findings provide insight into molecular mechanisms governing communication between chondrocytes and surrounding ECM components in bone growth activities.

Modulation of surface stiffness and cell patterning on polymer films using micropatterns

Here, a new technology was developed to selectively produce areas of high and low surface Young's modulus on biomedical polymer films using micropatterns. First, an elastic polymer film was adhered to a striped micropattern to fabricate a micropattern-supported film. Next, the topography and Young's modulus of the film surface were mapped using atomic force microscopy. Contrasts between the concave and convex locations of the stripe pattern were obvious in the Young's modulus map, although the topographical map of the film surface appeared almost flat. The concave and convex locations of a polymer film supported by a different micropattern also contrasted clearly. The resulting Young's modulus map showed that the Young's modulus was higher at convex locations than at concave locations. Hence, regions of high and low stiffness can be locally generated based on the shape of the micropattern supporting the film. When cells were cultured on the micropattern-supported films, NIH3T3 fibroblasts preferentially accumulated in convex regions with high Young's moduli. These findings demonstrate that this new technology can regulate regions of high and low surface Young's modulus on a cellular scaffold with high planar resolution, as well as providing a method for directing cellular patterning. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 976-985, 2018.

Simultaneous modified Camitz opponensplasty using a pulley at the radial side of the flexor retinaculum in severe carpal tunnel syndrome

Camitz opponensplasty using the palmaris longus has been used in patients undergoing open carpal tunnel release. It is considered to have several advantages over other opponensplasty techniques, but it provides weak flexion and pronation, which are prerequisites for opposition. To address this shortcoming, we have used a modified Camitz procedure with a pulley at the radial side of the dissected flexor retinaculum and have assessed the results in comparison with the conventional Camitz procedure. Both procedures provided significant improvements in palmar abduction and Disabilities of the Arm, Shoulder, and Hand and Kapandji scores at 3 months post-operatively, but patients who underwent the modified Camitz procedure showed better improvement in pulp pinch, palmar abduction, and thumb pronation.

Retroperitoneal approach for laparoscopic nephroureterectomy with stripping technique: extracorporeal ligation of ureter and ureteral catheter

INTRODUCTION

The pluck and stripping techniques are used for lower ureter management in renal pelvic cancer patients. Herein, we report our experience of extracorporeal ligation of the ureter and the ureteral catheter through the trocar port, which differs from conventional laparoscopic ligation in the retroperitoneal space. This technique was selected to reduce the time needed for ureter management using the stripping technique and to provide secure ligation.

MATERIALS AND SURGICAL TECHNIQUE

We performed this stripping technique in patients with T1 and T2 stage renal pelvic cancer without imaging-evident lymph node metastasis. After transurethrally placing a ureteral catheter, we resected the circumference of the ureteral orifice. After laparoscopic nephrectomy via a retroperitoneal approach, the ureteral catheter and distal ureter were ligated extracorporeally. The catheter was pulled to invaginate the ureter so it could then be pulled through the external urethral orifice.

DISCUSSION

This technique of extracorporeal ligation ensures more a secure ligation of the ureter and ureteral catheter. This modified stripping technique does not require lower ureter management with laparotomy, and it is also useful in shortening the operative time. This method is effective for relatively early stage renal pelvic cancer.