Propensity-score matched comparison of renal and neurohormonal effects of catheter ablation for frequent premature ventricular contractions in patients with and without systolic dysfunction

Background

Catheter ablation (CA) for premature ventricular contractions (PVCs) restores cardiac and renal functions in patients with reduced left ventricular ejection fraction (LVEF); however, its effects on preserved EF remain unelucidated.

Methods

The study cohort comprised 246 patients with a PVC burden of >10% on Holter electrocardiography. Using propensity matching, we compared the changes in B-type natriuretic peptide (BNP) levels and estimated glomerular filtration rate (eGFR) in patients who underwent CA or did not.

Results

Postoperative BNP levels were decreased significantly in the CA group, regardless of the degree of LVEF, whereas there was no change in those of the non-CA group. Among patients who underwent CA, BNP levels decreased from 44.1 to 33.0 pg/mL in those with LVEF ≥50% (p = .002) and from 141.0 to 87.9 pg/mL in those with LVEF <50% (p < .001). Regarding eGFR, postoperative eGFR was significantly improved in the CA group of patients with LVEF ≥50% (from 71.4 to 74.7 mL/min/1.73 m2, p = .006), whereas it decreased in the non-CA group. A similar trend was observed in the group with a reduced LVEF. Adjusted for propensity score matching, there was a significant decrease in the BNP level and recovery of eGFR after CA in patients with LVEF >50%.

Conclusions

This study showed that CA for frequent PVCs decreases BNP levels and increases eGFR even in patients with preserved LVEF.

Experimental study on Compton camera for boron neutron capture therapy applications

Boron neutron capture therapy (BNCT) is a high-dose-intensive radiation therapy that has gained popularity due to advancements in accelerator neutron sources. To determine the dose for BNCT, it is necessary to know the difficult-to-determine boron concentration and neutron fluence. To estimate this dose, we propose a method of measuring the prompt γ-rays (PGs) from the boron neutron capture reaction (BNCR) using a Compton camera. We performed a fundamental experiment to verify basic imaging performance and the ability to discern the PGs from 511 keV annihilation γ-rays. A Si/CdTe Compton camera was used to image the BNCR and showed an energy peak of 478 keV PGs, separate from the annihilation γ-ray peak. The Compton camera could visualize the boron target with low neutron intensity and high boron concentration. This study experimentally confirms the ability of Si/CdTe Compton cameras to image BNCRs.

A novel coronary angiographic index for predicting correlation between fractional flow reserve and resting full-cycle ratio

OBJECTIVES

The discordant results between fractional flow reserve (FFR) and resting full-cycle ratio (RFR) and the influence of angiographic characteristics on their correlation have not been sufficiently investigated. We aimed to identify angiographic characteristics that can predict FFR and RFR correlations using a novel angiographic scoring system.

METHODS

This retrospective analysis included 220 patients with 252 intermediate coronary lesions assessed using FFR and RFR. Each branch distal to the target lesion was scored based on the vessel diameter (0 points: < 1.5 mm, 1 point: 1.5-2.0 mm, and 2 points: > 2.0 mm) measured using quantitative coronary angiography. The angiographic score was calculated by adding these scores.

RESULTS

In a propensity score-matched cohort including 84 lesions (42 lesions in each low-and high-angiographic score group), the correlation between FFR and RFR in the high-angiographic score group (>4) was weaker than that in the low-score group (≤4) (Spearman's correlation: r = 0.44 vs. r = 0.80, P  < 0.01). Considering a threshold of functional myocardial ischemia as FFR ≤ 0.80 and RFR ≤ 0.89, the low-angiographic score group showed a significantly lower discordance rate of abnormal FFR/normal RFR than the high-angiographic score group (7.1% vs. 23.8%, P  = 0.03), whereas the discordance rates of normal FFR/abnormal RFR were similar in both groups (7.1% vs. 9.5%, P  = 0.69).

CONCLUSION

This retrospective analysis highlights the influence of angiographic characteristics on the correlation between FFR and RFR. Our simple angiographic assessment method may be useful for interpreting physiological evaluations in daily clinical practice.

Higher power achieves greater local impedance drop, shorter ablation time, and more transmural lesion formation in comparison to lower power in local impedance guided radiofrequency ablation of atrial fibrillation

BACKGROUND

Since the local impedance (LI) of the ablation catheter reflects tissue characteristics, the efficacy of higher power (HP) compared to lower power (LP) in LI-guided ablation may differ from other index-guided ablations.

OBJECTIVE

This study aimed to assess the efficacy of HP ablation in LI-guided ablation of atrial fibrillation (AF).

METHODS

A prospective observational study was conducted, enrolling patients undergoing de novo ablation for AF. Pulmonary vein isolation was performed using point-by-point ablation with a RHYTHMIA HDxTM Mapping System and an open-irrigated ablation catheter with mini-electrodes (IntellaNav MIFI OI). Ablation was stopped when the LI drop reached 30 ohms, three seconds after the LI plateaued, or when ablation time reached 30 s. To balance the baseline differences, a unique method was used in which the power was changed between HP (45 W to anterior wall/40 W to posterior wall) and LP (35 W/30 W) alternately for each adjacent point.

RESULTS

A total of 551 ablations in 10 patients were analyzed (HP, n = 276; LP, n = 275). The maximum LI drop was significantly larger (HP: 28.3 ± 5.4 vs. LP: 24.8 ± 6.3 ohm), and the time to minimum LI was significantly shorter (HP: 15.0 ± 6.3 vs. LP: 19.3 ± 6.6 s) in the HP setting. The unipolar electrogram analysis of three patients revealed that the electrogram indicating transmural lesion formation was observed more frequently in the HP setting.

CONCLUSION

In LI-guided ablation, the HP could achieve a larger LI drop and shorter time to minimum LI, which may result in more transmural lesion formation compared to a LP setting.

Improved Algorithm for Estimation of Linear Energy Transfer in Carbon Ion Radiotherapy Plans

BACKGROUND/AIM

This study aimed to develop an improved algorithm for linear energy transfer (LET) estimation in carbon ion radiotherapy (CIRT) using relative biological effectiveness (RBE) and to establish a clinical pipeline for LET assessment.

MATERIALS AND METHODS

New approximation functions for LET versus RBE were developed for the overkill region. LET estimation performance was examined at two facilities (A and B) using archival- and Monte Carlo simulation-derived LET data, respectively, as a reference. A clinical pipeline for LET assessment was developed using Python and treatment planning systems (TPS).

RESULTS

In dataset A, LET estimation accuracy in the overkill region was improved by 80.0%. In dataset B, estimation accuracy was 2.3%±0.67% across 5 data points examined. LET distribution and LET-volume histograms were visualized for multiple CIRT plans.

CONCLUSION

The new algorithm showed a greater LET estimation performance at multiple facilities using the same TPS. A clinical pipeline for LET assessment was established.

Analysis of the relationship between LET, γH2AX foci volume and cell killing effect of carbon ions using high-resolution imaging technology

The strong cell killing effect of high linear energy transfer (LET) carbon ions is dependent on lethal DNA damage. Our recent studies suggest that induction of clusters of double-strand breaks (DSBs) in close proximity is one of the potential mechanisms. However, the relationship between LET, the degree of DSB clustering and the cell killing effect of carbon ions remains unclear. Here, we used high-resolution imaging technology to analyze the volume of γH2AX foci induced by monoenergetic carbon ions with a clinically-relevant range of LET (13-100 keV/μm). We obtained data from 3317 γH2AX foci and used a gaussian function to approximate the probability (p) that 1 Gy-carbon ions induce γH2AX foci of a given volume (vth) or greater per nucleus. Cell killing effects were assessed in clonogenic assays. The cell killing effect showed high concordance with p at vth = 0.7 μm3 across various LET values; the difference between the two was 4.7% ± 2.2%. This relationship was also true for clinical carbon ion beams harboring a mixed LET profile throughout a spread-out Bragg peak width (30-120 mm), with the difference at vth = 0.7 μm3 being 1.6% ± 1.2% when a Monte Carlo simulation-derived dose-averaged LET was used to calculate p. These data indicate that the cell killing effect of carbon ions is predictable by the ability of carbon ions to induce γH2AX foci containing clustered DSBs, which is linked to LET, providing the biological basis for LET modulation in the planning of carbon ion radiotherapy.

Clinical dose assessment for scanned carbon-ion radiotherapy using linear energy transfer measurements and Monte Carlo simulations

Objective. Dosimetric commissioning of treatment planning systems (TPS) focuses on validating the agreement of the physical dose with experimental data. For carbon-ion radiotherapy, the commissioning of the relative biological effectiveness (RBE) is necessary to predict the clinical outcome based on the radiation quality of the mixed radiation field. In this study, we proposed a approach for RBE commissioning using Monte Carlo (MC) simulations, which was further strengthen by RBE validation based on linear energy transfer (LET) measurements.Approach. First, we tuned the MC simulation based on the results of dosimetric experiments including the beam ranges, beam sizes, and MU calibrations. Furthermore, we compared simulated results to measured depth- and radial-LET distributions of the 430 MeV u^-1carbon-ion spot beam with a 1.5 mm², 36μm thick silicon detector. The measured dose-averaged LET (LET_d) and RBE were compared with the simulated results. The RBE was calculated based on the mixed beam model with linear-quadratic parameters depending on the LET. Finally, TPS-calculated clinical dose profiles were validated through the tuned MC-based calculations.Main results. A 10 keVμm^-1and 0.15 agreement for LET_dand RBE, respectively, were found between simulation and measurement results obtained for a 2σlateral size of 430 MeV u^-1carbon-ion spot beam in water. These results suggested that the tuned MC simulation can be used with acceptable precision for the RBE and LET calculations of carbon-ion spot beam within the clinical energy range. For physical and clinical doses, the TPS- and MC-based calculations showed good agreements within 1.0% at the centre of the spread-out Bragg peaks.Significance. The tuned MC simulation can accurately reproduce the actual carbon-ion beams, and it can be used to validate the physical and clinical dose distributions calculated by TPS. Moreover, the MC simulation can be used for dosimetric commissioning, including clinical doses, without LET measurements.

The Prognostic Value of B-Type Natriuretic Peptide in Patients With Cardiac Sarcoidosis Without Heart Failure: Insights From ILLUMINATE-CS

Background The prognostic role of BNP (B-type natriuretic peptide) in patients with cardiac sarcoidosis without evident heart failure is unknown. Methods and Results This is a post hoc analysis of ILLUMINATE-CS (Illustration of the Management and Prognosis of Japanese Patients With Cardiac Sarcoidosis), a multicenter, retrospective, and observational study that evaluated the clinical characteristics and prognosis of cardiac sarcoidosis. We analyzed patients with cardiac sarcoidosis without evident heart failure at the time of diagnosis. The association between baseline BNP levels and prognosis was investigated. The primary end point was the combined end point of all-cause death, heart failure hospitalization, and fatal ventricular arrhythmia. In total, 238 patients (61.0±11.1 years, 37% men) were analyzed, and 61 primary end points were observed during a median follow-up period of 3.0 (interquartile range, 1.7-5.8) years. Patients with high BNP (BNP above the median value of BNP) were older and had a lower renal function and left ventricular ejection fraction than those with low BNP values. Kaplan-Meier curve analysis indicated that high BNP levels were significantly associated with a high incidence of primary end points (log-rank P=0.004), and this association was retained even in multivariable Cox regression (hazard ratio, 2.06 [95% CI, 1.19-3.55]; P=0.010). Log-transformed BNP as a continuous variable was associated with the primary end point (hazard ratio, 2.12 [95% CI, 1.31-3.43]; P=0.002). Conclusions High baseline BNP level was an independent predictor of future adverse events in patients with cardiac sarcoidosis without heart failure at the time of diagnosis. Registration URL: https://www.umin.ac.jp/english/; Unique Identifier: UMIN-CTR: UMIN000034974.

The angle of the tines before the pull and hold test predicts engagement of the tines in Micra leadless pacemaker implantation

Background

Micra leadless pacemaker is secured to the myocardium by engagement of at least 2/4 tines confirmed with pull and hold test. However, the pull and hold test is sometimes difficult to assess. This study was performed to evaluate whether the angle of the tines before the pull and hold test predicts engagement of the tines in Micra leadless pacemaker implantation.

Methods

We retrospectively enrolled 93 consecutive patients (52.7% male, age 82.4 ± 9.4 years), who received Micra implantation from September 2017 to June 2020 at our institution. After deployment and before the pull and hold test, the angle of the visible tines to the body of the pacemaker was measured using the RAO view of the fluoroscopy image. The engagement of the tines was then confirmed with the pull and hold test.

Results

A total of 326 tines were analyzed. The angle of the engaged tines was significantly lower than the non-engaged tines (9.2 degrees [4.0-14.0] vs. 16.6 degrees [14.2-18.8], p < .0001). All tines with angles <10 degrees were engaged. In higher angles, engagement could not be predicted.

Conclusion

A low angle of the tines before the pull and hold test can predict engagement of the tines in Micra leadless pacemaker implantation. The tines which are already open after deployment may be presumed that they are engaged.

Normal Tissue Complication Probability Model for Acute Radiation Dermatitis in Patients with Head and Neck Cancer Treated with Carbon Ion Radiotherapy

PURPOSE

This study aimed to explore the prognostic factors associated with acute radiation dermatitis (ARD). A normal tissue complication probability (NTCP) model for ARD in patients with head and neck cancer (HNC) treated with carbon ion radiotherapy (CIRT) was developed.

MATERIALS AND METHODS

A total of 187 patients were included in the analysis, and the endpoint was ≥grade 2 ARD. The biological and physical dose-surface parameters associated with ARD were used in the logistic regression model. The mean areas under the receiver operating characteristic curve (AUC) in the internal cross-validation and Akaike's corrected Information Criterion (AICc) were examined for model evaluation and selection. The multivariate logistic regression NTCP models were established based on factors with weak correlation.

RESULTS

Tumour volume, planning target volume to the skin, radiation technique and all dose-surface parameters were significantly associated with ARD (P < 0.05). Models with high performance for grade 2-3 ARD were constructed. The most significant prognostic predictors were S_{40 Gy (relative biological effectiveness, RBE)} and S_{20 Gy} [absolute surface area receiving RBE-weighted dose of 40 Gy (RBE) or physical dose of 20 Gy]. The internal cross-validation-based AUCs for models with S_{40 Gy (RBE)} and S_{20 Gy} were 0.78 and 0.77, respectively. The biological and physical dose-surface parameters had similar performance at various dose levels. However, the performance of the multivariate NTCP models based on two factors was not better than that of the univariate models.

CONCLUSIONS

NTCP models for ARD may provide a basis for the development of individualised treatment strategies and reduce the incidence of severe ARD in patients with HNC receiving CIRT. Furthermore, biological and physical dose-surface parameter-based models are comparable. However, further validation with more evaluation parameters is warranted.

Leadless pacemaker implantation sites confirmed by computed tomography and their parameters and complication rates

BACKGROUND

Implantations of leadless pacemakers in the septum lower the risk of cardiac perforation. However, the relationship between the implantation site and the success rate, complication rate, and pacemaker parameters are not well-investigated.

METHODS

Patients who underwent leadless pacemaker implantation with postprocedural computed tomography (CT) between September 2017 and November 2020 were analyzed. Septum was targeted with fluoroscopic guidance with contrast injection. We divided patients into two groups based on the implantation site confirmed by CT: septal and non-septal, which included the anterior/posterior edge of the septum and free wall. We compared the complication rates and pacemaker parameters between the two groups.

RESULTS

A total of 67 patients underwent CT after the procedure; among them, 28 were included in the septal group and 39 were included in the non-septal group. The non-septal group had significantly higher R wave amplitudes (6.5 ± 3.3 vs. 9.7 ± 3.9 mV, p = .001), lower pacing threshold (1.0 ± 0.94 vs. 0.63 ± 0.45 V/0.24 ms, p = .02), and higher pacing impedance (615 ± 114.1 vs. 712.8 ± 181.3 ohms, p = .014) after the procedure compared to the septal group. Cardiac injuries were observed in four patients (one cardiac tamponade, one possible apical hematoma, two asymptomatic pericardial effusion), which were only observed in the non-septal group.

CONCLUSIONS

Leadless pacemaker implantation may be technically challenging with substantial number of patients with non-septal implantation when assessed by CT. Septal implantation may have a lower risk of cardiac injury but may lead to inferior pacemaker parameters than non-septal implantation.

Three-dimensional dose-distribution measurement of therapeutic carbon-ion beams using a ZnS scintillator sheet

The accurate measurement of the 3D dose distribution of carbon-ion beams is essential for safe carbon-ion therapy. Although ionization chambers scanned in a water tank or air are conventionally used for this purpose, these measurement methods are time-consuming. We thus developed a rapid 3D dose-measurement tool that employs a silver-activated zinc sulfide (ZnS) scintillator with lower linear energy transfer (LET) dependence than gadolinium-based (Gd) scintillators; this tool enables the measurement of carbon-ion beams with small corrections. A ZnS scintillator sheet was placed vertical to the beam axis and installed in a shaded box. Scintillation images produced by incident carbon-ions were reflected with a mirror and captured with a charge-coupled device (CCD) camera. A 290 MeV/nucleon mono-energetic beam and spread-out Bragg peak (SOBP) carbon-ion passive beams were delivered at the Gunma University Heavy Ion Medical Center. A water tank was installed above the scintillator with the water level remotely adjusted to the measurement depth. Images were recorded at various water depths and stacked in the depth direction to create 3D scintillation images. Depth and lateral profiles were analyzed from the images. The ZnS-scintillator-measured depth profile agreed with the depth dose measured using an ionization chamber, outperforming the conventional Gd-based scintillator. Measurements were realized with smaller corrections for a carbon-ion beam with a higher LET than a proton. Lateral profiles at the entrance and the Bragg peak depths could be measured with this tool. The proposed method would make it possible to rapidly perform 3D dose-distribution measurements of carbon-ion beams with smaller quenching corrections.

Outcomes of deep sedation for catheter ablation of paroxysmal supraventricular tachycardia, with adaptive servo ventilation

BACKGROUND

Catheter ablation for paroxysmal supraventricular tachycardia (PSVT) is an established treatment, but the effect of deep sedation on PSVT inducibility remains unclear.

AIM

We sought to examine PSVT inducibility and outcomes of catheter ablation under deep sedation using adaptive servo ventilation (ASV).

METHODS

We retrospectively evaluated consecutive patients who underwent catheter ablation for PSVT under deep sedation (Propofol + Dexmedetomidine) with use of ASV. Anesthetic depth was controlled with BIS™ monitoring, and phenylephrine was administered to prevent anesthesia-induced hypotension. PSVT induction was attempted in all patients using extrastimuli at baseline, and after isoproterenol (ISP) infusion when necessary.

RESULTS

PSVT was successfully induced in 145 of 147 patients, although ISP infusion was required in the majority (89%). The PSVT was atrioventricular nodal reentrant tachycardia (AVNRT) in 77 (53%), atrioventricular reciprocating tachycardia (AVRT) in 51 (35%), and atrial tachycardia (AT) in 17 (12%). A higher ISP dose was required for AT compared to other PSVT (AVNRT: 0.06 (IQR 0.03-0.06) vs AVRT: 0.03 (0.02-0.06) vs AT: 0.06 (0.03-0.12) mg/h, P = .013). More than half (51%) of the patients developed hypotension requiring phenylephrine; these patients were older. Acute success was obtained in 99% (patients with AVNRT had endpoints with single echo on ISP in 46%). Long-term success rate was 136 of 144 (94%) (AVNRT 96%, AVRT 92%, and AT 93%). There were no complications related to deep sedation.

CONCLUSIONS

Deep sedation with use of ASV is a feasible anesthesia strategy for catheter ablation of PSVT with good long-term outcome. PSVT remains inducible if ISP is used.

Clinical impact of serial change in brain natriuretic peptide before and after catheter ablation in patients with atrial fibrillation and heart failure

BACKGROUND

Brain natriuretic peptide (BNP) predicts the prognosis in patients with atrial fibrillation (AF) and heart failure (HF); however, the level of BNP can change immediately after restoration of sinus rhythm. We aimed to investigate the clinical impact of serial change in BNP level before and after catheter ablation for AF, on the prognosis.

METHODS

In this retrospective single center study, 162 consecutive patients (67±9 years, 66.7% male) with AF and concomitant HF who underwent catheter ablation were examined. We analyzed the cardiac rhythm and % change in BNP pre- and post-ablation.

RESULTS

BNP increased by 32.7% (-4.5% to 51.3%) in patients with sinus rhythm at baseline (sinus rhythm group: N=50) and decreased by 47.6% (20.9 to 61.6%) in patients with AF rhythm at baseline. Patients with AF rhythm at baseline were categorized into two groups according to the median value of reduction in % BNP; patients with good % BNP reduction (good BNP-R group; N=56), and with poor % BNP reduction (poor BNP-R group; N=56). Although the rate of recurrence of AF after ablation was comparable between the good and poor BNP-R groups, poor BNP-R was an independent predictor of subsequent composite events including HF hospitalization, ischemic stroke, and all cause of death after ablation, even after adjusting for other confounders (hazard ratio: 6.85, 95% confidence interval: 2.16 to 21.7, p-value=0.001). In the longitudinal analysis of echocardiographic parameters, shortening of the left ventricular end-diastolic diameter with preserved ejection fraction was evident except in the poor BNP-R group.

CONCLUSION

In patients with AF and HF, poor % BNP reduction was an independent predictor of adverse outcome, although the rate of recurrence of AF was comparable. Serial BNP measurement might help in better identification of high-risk patients in whom sinus rhythm is restored with catheter ablation.

Efficacy of cardiac rehabilitation with motion assistance from wearable cyborg hybrid assistive limb in patients with chronic heart failure: a randomized controlled trial

Background

Recent Cochrane Systematic Review suggested that the participation in cardiac rehabilitation is associated with approximately 20% lower cardiovascular mortality and morbidity. Exercise therapy is the key component of cardiac rehabilitation programs. In recent years, innovative technologies have been introduced into the field of rehabilitation, and a typical example is the wearable cyborg Hybrid Assistive Limb (HAL). The wearable cyborg HAL provides motion assistance based on detection of bioelectrical signals on the skin surface when muscle forces are generated. The lumbar-type HAL is expected to expand the therapeutic options for severe cardiac patients who have difficulty in performing usual cardiac rehabilitation programs, such as bicycle pedaling or walking.

Purpose

We aim to compare the efficacy of exercise therapy performed with motion assistance from a lumbar-type HAL versus conventional training (sit-to-stand exercise without HAL) in patients with chronic heart failure.

Methods

This clinical trial is a randomized, non-blinded, and controlled study. Twenty-eight heart failure patients (73.1±13.8 years) who have difficulty in walking at the usual walking speed of healthy subjects were randomly assigned to 2 groups (HAL group or control group) with a 1:1 allocation ratio and performed sit-to stand exercise either with HAL or without HAL for 5 to 30 minutes once a day, and 6 to 10 days during the study period. The brain natriuretic peptide (BNP), isometric knee extensor strength, standing ability (30-seconds chair-stand test: CS-30), short physical performance battery (SPPB) and 6-minute walking distance (6MWD) were measured before and after the completion of cardiac rehabilitation. Cardiac events such as death, re-hospitalization, myocardial infarction and worsening of angina pectoris and heart failure during 1 year after discharge were evaluated.

Results

There was no significant difference in the number of days of exercise therapy between the two groups. BNP, SPPB and 6MWD were improved in both groups. In the HAL group, the isometric knee extensor strength (0.29±0.11 vs 0.35±0.11 kgf/kg, p=0.003) significantly improved and CS-30 (5.5±5.1 vs 8.2±5.3, p=0.054) tended to improve. However, in the control group, either the isometric knee extensor strength (0.35±0.11 vs 0.36±0.14 kgf/kg, p=0.424) or CS-30 (6.0±4.3 vs 9.2±6.2, p=0.075) did not significantly change. HAL group showed significantly more improvement in the isometric knee extensor strength than control group (p=0.045). Cardiac events occurred in 20% in the HAL group and 43% in the control group.

Conclusion

The improvement in isometric knee extensor strength with the assistance from lumbar-type HAL suggests that exercise therapy using this device may be useful in chronic heart failure patients with flail or sarcopenia, a strong poor prognostic factor in these patients.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported in part by a grant-in-aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan (JSPS KAKENHI grant number JP17K09485) and funded by the ImPACT Program of the Council for Science, Technology and Innovation (Cabinet Office, Government of Japan) (grant number 2017-PM05-03-01).

Risk factors for venous bleeding complication at the femoral puncture site after catheter ablation of atrial fibrillation

BACKGROUND

Venous bleeding complication is often observed after catheter ablation of atrial fibrillation (AF), but the risk factors remain unclear.

METHODS

We retrospectively evaluated 570 consecutive patients who underwent catheter ablation of AF from April 2012 to March 2017. After the procedure, the sheaths were removed, and hemostasis was obtained by manual compression followed by application of rolled gauze with elastic bandage and continuous pressure to the puncture site. We evaluated the risk factors for venous bleeding complications defined as hemorrhage from the puncture site that needed recompression after removal of the elastic bandage and rolled gauze.

RESULTS

After excluding 11 patients because of missing data, 559 patients (395 [70.7%] men, mean age: 65.6 ± 8.7 years) were included for analysis. Venous bleeding complication was observed in 213 patients (38.1%). In the multivariate logistic regression analysis, low body mass index (BMI; odds ratio [OR] 0.95, 95% CI 0.90-1.00, P = .04), short compression time (OR 0.77, 95% CI 0.68-0.88, P < .001), and antiplatelet therapy (OR 1.86, 95% CI 1.09-3.16, P = .02) were independent risk factors for venous bleeding complication.

CONCLUSIONS

Low BMI, short compression time, and antiplatelet therapy were independent risk factors for venous bleeding complication after catheter ablation of AF. Longer compression time may be needed for patients with low BMI and/or those receiving antiplatelet therapy.

Impact of brain natriuretic peptide reduction on the worsening renal function in patients with acute heart failure

Aims

The prognostic impact of worsening renal function (WRF) in patients with acute heart failure (AHF) remains under debate. Successful decongestion might offset the negative impact of WRF, but little is known about indicators of successful decongestion in the very acute phase of AHF. We hypothesized that decongestion as evaluated by the percent reduction in brain natriuretic peptide (BNP) could identify relevant prognostic implications of WRF in the very acute phase of AHF.

Methods and results

Data on 907 consecutive hospitalized patients with AHF in the REALITY-AHF study (age: 78±12 years; 55.1% male) were analyzed. Creatinine and BNP were measured at baseline and 48 hours from admission. WRF was defined as an increase in creatinine >0.3 mg at 48 hours from admission. The primary endpoint was 1-year all-cause mortality. Patients were divided into four groups according to the presence/absence of WRF and a BNP reduction higher/lower than the median: no-WRF/higher-BNP-reduction (n = 390), no-WRF/lower-BNP-reduction (n = 397), WRF/higher-BNP-reduction (n = 63), and WRF/lower-BNP-reduction groups (n = 57). Kaplan-Meier curve analysis showed that the WRF/lower-BNP-reduction group had a worse prognosis than the other groups. In a Cox regression analysis, only the WRF/lower-BNP-reduction group had higher mortality compared to the no-WRF/higher-BNP-reduction group (hazard ratio: 3.34, p<0.001).

Conclusion

In the very acute phase of AHF, BNP reduction may aid in identifying relevant prognostic significance of WRF.

Predictive value of noninducibility after catheter ablation for paroxysmal and persistent atrial fibrillation

Background

It is unclear whether pacing maneuver at the end of catheter ablation for atrial fibrillation (AF) predicts recurrence of atrial tachyarrhythmia postintervention.

Objective

To investigate whether the predictive value of incremental pacing maneuver after catheter ablation for AF depends on the pacing cycle length and type of AF.

Methods

This study included 298 consecutive patients who underwent initial catheter ablation for nonvalvular AF (61% paroxysmal AF [PAF], 39% persistent AF [PeAF]). Rapid atrial pacing was performed at the end of the procedure. We analyzed minimum coupling interval (CI) of pacing, arrhythmia‐inducibility, and atrial tachyarrhythmia recurrence in patients with PAF and PeAF.

Results

Patients were divided into the following three groups according to their response to pacing maneuver: AF‐inducible (inducible group; n = 86), noninducible at CI ≥200 ms (non‐CI ≥200 group; n = 100), and noninducible at CI <200 ms (non‐CI <200 group; n = 112). Kaplan‐Meier analysis showed that response to pacing maneuver was significantly associated with recurrence of atrial tachyarrhythmias (P = .028). Cox‐regression analysis showed that non‐CI <200 was an independent predictor when the inducible group was used as a reference (hazard ratio 0.60, 95% confidence interval 0.40‐0.96, P = .031). However, when PAF and PeAF were analyzed separately, non‐CI <200 was an independent predictor only in PeAF.

Conclusion

Noninducibility with shorter CI predicted atrial tachyarrhythmia recurrence only for PeAF. Pacing CI and type of AF could influence the predictive value of atrial tachyarrhythmia recurrence.

In vivo measurement of stent length by using intravascular ultrasound

Background

What happens to stent length when deployed in a coronary artery? It is the aim of this study.

Results

Consecutive 95 balloon-expandable stents (BES) were studied by intravascular ultrasound (IVUS) imaging. The stent length was measured from the longitudinal view in two ways: (1) edge-to-edge length (E-E) measured between distal and proximal stent frames located at one IVUS quadrant and (2) area-to-area length (A-A) measured between distal and proximal stent frames located at two or more IVUS quadrants. IVUS measurements were compared with the manufacturer-stated length (M-L). The median E-E length was significantly longer than M-L, 18.76 mm [interquartile range (IQR) 15.65–23.60] versus 18.00 mm (IQR 15.00–23.00), respectively, p < 0.0001. Also, the median A-A length was significantly longer, 18.36 mm (IQR 15.19–23.47), p < 0.0001, than M-L. Moreover, the E-E length was significantly different from A-A length, p < 0.0001. Among the stent groups, the differences were significantly present in all drug-eluting stent and bare metal stent (BMS) comparisons, p < 0.0001, except the A-A length versus M-L in BMS only. By multivariate analysis, the predictors of difference in stent length were as follows: lesion length, p = 0.01; pre-intervention minimal diameter of the external elastic membrane (EEM), p = 0.03; lesions present in the left anterior descending branch, p = 0.03; and M-L, p = 0.04.

Conclusions

In the present study, the length of BES measured by IVUS was significantly different from the manufacturer-stated length. In addition to the manufacturer length, other important factors such as lesion length, pre-intervention diameter of EEM, and affected vessel determine the stent length.

Study on the RBE estimation for carbon beam scanning irradiation using a solid-state microdosimeter

PURPOSE

The purpose of this study was to study the field size effect on the estimated Relative Biological Effectiveness (RBE) for carbon scanning beam irradiation.

METHODS

A silicon-on-insulator (SOI) microdosimeter system developed by the Centre for Medical Radiation Physics, University of Wollongong, Australia, was used for lineal-energy measurements (microdosimetric quantity). The RBE values were derived based on the modified microdosimetric kinetic model (MKM) at different depths in a water phantom in the scanning carbon beam for various scanned areas.

RESULTS

Our study shows that the difference in RBE values derived from the SOI microdosimeter measurements with the MKM model and from the Treatment Planning System (TPS). The difference of the RBE values is within 6.5 % at the peak point of the spread-out Bragg Peak (SOBP) region. Compared to the spot-beam, RBE values obtained in the scanned-beam with a larger scanned area of 1.0 × 1.0 cm² have better agreement with which estimated by the TPS.

CONCLUSIONS

This study shows the possibility of using the SOI microdosimeter system as a quality assurance (QA) tool for RBE evaluation in carbon-pencil beam scanning radiotherapy.

Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction

Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, ep→e^{'}pω, at central Q^{2} values of 1.60, 2.45  GeV^{2}, at W=2.21  GeV. The results of our pioneering -u≈-u_{min} study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^{2}=2.45  GeV^{2}, the observed dominance of σ_{T} over σ_{L}, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics.

P6154Association between n-3 and n-6 polyunsaturated fatty acids and plaque vulnerability by optical coherence tomography in acute myocardial infarction patients

Background

The values of n-3 and n-6 polyunsaturated fatty acids (PUFAs) like low eicosapentaenoic acid (EPA) /arachidonic acid (AA) ratio are known to be associated with cardiovascular events, however their relationship with coronary plaque vulnerability in acute myocardial infarction (AMI) is not revealed.

Purpose

We evaluated the relationship between n-3 and n-6 PUFAs and coronary plaque vulnerability assessed by optical coherence tomography (OCT) in AMI patients.

Methods

We investigated 79 AMI lesions (51 ST elevated myocardial infarction (STEMI) lesions and 28 non-STEMI lesions) that had undergone emergency percutaneous coronary intervention using OCT. Coronary plaque characteristics by OCT were compared with n-3 and n-6 PUFAs values which were measured on admission.

Results

Of all AMI lesions (n=79), 43 thin-cap fibroatheroma (TCFA) and 35 plaque rapture (PR) were detected by OCT. Lesions with TCFA had no significant relationship with n-3 and n-6 PUFAs values, whereas lesion with PR had significantly lower EPA values than those without (55.8±29.5 vs 74.3±37.1 μg/ml, p=0.018). Median low-density lipoprotein (LDL) cholesterol value was 117 (98–137) mg/dl and sub-analysis in patients who had lower LDL cholesterol values than median (n=39) revealed that EPA values were significantly lower in lesions with TCFA (56.3±30.9 vs 85.3±47.7 μg/ml, p=0.03). In STEMI patients, the values of EPA and EPA/AA ratio were significantly lower in lesions with TCFA (EPA: 55.5±22.8 vs 80.8±46.1 μg/ml, p=0.01; EPA/AA ratio: 0.34±0.16 vs 0.50±0.36, p=0.03). STEMI patients who had lower LDL cholesterol values <114 mg/dl of median (n=26), the values of EPA, EPA/AA ratio, and EPA+ docosahexaenoic acid (DHA) /AA ratio were significantly lower in lesions with TCFA (EPA: 51.4±20.7 vs 93.1±53.0 μg/ml, p=0.01; EPA/AA ratio: 0.37±0.16 vs 0.67±0.41, p=0.01; EPA+DHA/AA ratio: 1.13±0.41 vs 1.63±0.76, p=0.04). In STEMI patients with lower LDL cholesterol values, EPA/AA ratio positively correlated with fibrous cap thickness (Spearman, ρ=0.35, p=0.08). The cutoff value of EPA/AA ratio predicting the existence of TCFA was 0.52 (area under the curve 0.78, sensitivity 93.8%, specificity 70.0%, p=0.02).

Conclusion

This study demonstrated that n-3 and n-6 PUFAs values were associated with coronary plaque vulnerability by OCT in AMI patients, especially in STEMI. These results suggest that n-3 and n-6 PUFAs may be residual risk markers of severe acute cardiovascular events in patients with low LDL cholesterol values.

Intratumoural immune cell landscape in germinoma reveals multipotent lineages and exhibits prognostic significance

AIMS

Alterations in microenvironments are a hallmark of cancer, and these alterations in germinomas are of particular significance. Germinoma, the most common subtype of central nervous system germ cell tumours, often exhibits massive immune cell infiltration intermingled with tumour cells. The role of these immune cells in germinoma, however, remains unknown.

METHODS

We investigated the cellular constituents of immune microenvironments and their clinical impacts on prognosis in 100 germinoma cases.

RESULTS

Patients with germinomas lower in tumour cell content (i.e. higher immune cell infiltration) had a significantly longer progression-free survival time than those with higher tumour cell contents (P = 0.03). Transcriptome analyses and RNA in-situ hybridization indicated that infiltrating immune cells comprised a wide variety of cell types, including lymphocytes and myelocyte-lineage cells. High expression of CD4 was significantly associated with good prognosis, whereas elevated nitric oxide synthase 2 was associated with poor prognosis. PD1 (PDCD1) was expressed by immune cells present in most germinomas (93.8%), and PD-L1 (CD274) expression was found in tumour cells in the majority of germinomas examined (73.5%).

CONCLUSIONS

The collective data strongly suggest that infiltrating immune cells play an important role in predicting treatment response. Further investigation should lead to additional categorization of germinoma to safely reduce treatment intensity depending on tumour/immune cell balance and to develop possible future immunotherapies.

Inferior Vena Cava Thrombus due to Left Inferior Vena Cava and Ulcerative Colitis

A 29-year-old man with diarrhea and abdominal pain for 2 weeks presented with new-onset left back pain. Contrast-enhanced computed tomography (CT) showed a left inferior vena cava (IVC) crossing over the aorta, and thrombus in the IVC and left renal vein. Colonoscopy and biopsy for assessment of diarrhea and abdominal pain provided a diagnosis of ulcerative colitis. Stasis of blood flow due to left IVC crossing over the aorta, and hypercoagulability due to ulcerative colitis influenced thrombus formation.

Linear energy transfer (LET) spectra and survival fraction distribution based on the CR-39 plastic charged-particle detector in a spread-out Bragg peak irradiation by a 12C beam

Facilities for heavy ion therapies are steadily increasing in number worldwide. One of the advantages of heavy ions is their high relative biological effect (RBE). In a model used at NIRS (National Institute of Radiological Sciences), linear energy transfer (LET) spectra are required to estimate biological dose (physical dose  ×  RBE). The CR-39 plastic charged-particle detector (CR-39) is suitable for measurement of LET. For the present study, done at the Gunma University Heavy Ion Medical Center (GHMC), we measured LET spectra at 11 depths in spread-out Bragg peak (SOBP) irradiation by a ¹²C beam of 380 MeV/u. The lower threshold of the CR-39 to measure LET was about 5 keV µm^-1 due to poor sensitivity for low LET. Then we calculated biological dose and survival fraction distributions and compared them with treatment planning results at GHMC. We used Monte Carlo simulation (Geant4) to calculate LET spectra. The simulation results were in good agreement with the experimental spectra. Moreover, the biological dose and survival fraction distributions estimated from the CR-39 reproduced the treatment planning. The CR-39 is suitable for estimating biological dose in carbon ion therapy.

Implications of right ventricular septal pacing for medium-term prognosis: Propensity-matched analysis

BACKGROUND

The effect of right ventricular (RV) septal pacing as opposed to RV apical pacing on prognosis in patients undergoing pacemaker implantation remains controversial. This study was performed to examine the clinical efficacy of RV septal pacing in a large cohort with medium-term follow-up and propensity-matched analysis.

METHODS

A total of 982 consecutive patients with first pacemaker implantation between 2008 and 2013 at two centers in Japan (51.4% male, age 76.1±10.6years, 64.3% septal pacing, 94% preserved ejection fraction [EF]) were enrolled. Propensity matching successfully matched 446 patients into RV septal and apical pacing groups. The primary endpoint, a combination of all-cause death and hospitalization due to heart failure, was compared between the two groups.

RESULTS

In the propensity-matched cohort, the primary endpoint was observed in 61 patients (13.7%) over a median follow-up period of 2.1years (interquartile range, 1.1-3.5years). The effects of septal pacing on prognosis were not statistically significant (hazard ratio [HR]=1.10, 95% confidence interval [CI]=0.60-2.04, P=0.752). No significant benefit of septal pacing was observed on all-cause death (HR=1.86, 95%CI=0.74-4.66, P=0.187) and heart failure hospitalization (HR=0.93, 95%CI=0.44-1.98, P=0.847) when assessed separately.

CONCLUSION

Septal pacing did not show medium-term advantages in prognosis in this large-scale retrospective cohort study with propensity matching of patients with predominantly preserved EF.