Arterial Healing 10 Months After Implantation of an Ultrathin-Strut, Biodegradable-Polymer, Sirolimus-Eluting Stent - An Angioscopic Study

Background: The Orsiro^TM ultrathin-strut, biodegradable-polymer, sirolimus-eluting stent (O-SES) has specific characteristics regarding its components and has demonstrated comparable clinical outcomes compared with durable-polymer, drug-eluting stents (DES). However, arterial repair following deployment of the O-SES has not been elucidated to date.

Methods and Results: Using data from the Kansai Rosai Hospital database between November 2010 and September 2020, we analyzed coronary angioscopy (CAS) findings a mean (±SD) of 10±2 months after implantation of an O-SES, a durable-polymer everolimus-eluting stent (Xience^TM; X-EES), or a biodegradable-polymer everolimus-eluting stent (Synergy^TM; S-EES). Neointimal coverage (NIC), yellow color intensity of the stented segment, and the incidence of thrombus adhesion were compared between the O-SES (66 stents from 42 patients), X-EES (119 stents from 87 patients), and S-EES (132 stents from 88 patients). NIC was significantly thinner for the O-SES than S-EES (P<0.001), but was similar between the O-SES and X-EES (P=0.25). Yellow color intensity was significantly greater for the O-SES than X-EES (P<0.001), but similar between the O-SES and S-EES (P=0.51). The incidence of thrombus adhesions was similar in all 3 groups.

Conclusions: O-SES and X-EES resulted in similar inhibition of NIC and both resulted in a thinner NIC than with S-EES. In addition, O-SES exhibited a similar degree of thrombus adhesion as the other DES, suggesting similar thrombogenicity.

Saphenous vein size as a surrogate marker for mortality of patients with chronic limb-threatening ischemia undergoing endovascular therapy

BACKGROUND

The size of the autologous vein graft is an important determinant of prognosis in patients with chronic limb-threatening ischemia (CLTI) undergoing bypass surgery. However, it is unclear whether reconstruction using a small vein graft would directly affect prognosis, or a subgroup having small veins would be subject to a poor prognosis. If the latter is true, having small veins would work as a marker for a poor prognosis even in patients with CLTI undergoing endovascular therapy (EVT). Therefore, we investigated the association between the size of saphenous veins and prognosis in patients with CLTI undergoing EVT.

METHODS

This study included 209 consecutive patients with CLTI who primarily underwent EVT between January 2017 and December 2018. The diameter of the saphenous vein was measured at three locations (saphenous-femoral junction, knee, and ankle joint) per limb before EVT by ultrasonography. A small saphenous vein was defined as the mean diameter <3.0 mm.

RESULTS

All-cause mortality rate was significantly higher in patients with a small saphenous vein than in those with non-small one (46.3% versus 10.7% at 2 years, p<0.001). The multivariate Cox regression analysis revealed that a small saphenous vein was independently associated with an increased risk of all-cause mortality.

CONCLUSIONS

Having a small saphenous vein was an independent marker for all-cause mortality in patients with CLTI undergoing EVT.

Central retinal artery occlusion after catheter ablation of atrial fibrillation

Central retinal artery occlusion (CRAO) is a rare but severe and urgent complication of atrial fibrillation ablation. Awareness of this ophthalmologic complication and prompt treatment are needed because ischemic damage to the retina is irreversible from 4 hours after the onset of CRAO.

Test of Lepton-Flavor Universality in B→K^{*}ℓ^{+}ℓ^{-} Decays at Belle

We present a measurement of R_{K^{*}}, the branching fraction ratio B(B→K^{*}μ^{+}μ^{-})/B(B→K^{*}e^{+}e^{-}), for both charged and neutral B mesons. The ratio for the charged case R_{K^{*+}} is the first measurement ever performed. In addition, we report absolute branching fractions for the individual modes in bins of the squared dilepton invariant mass q^{2}. The analysis is based on a data sample of 711  fb^{-1}, containing 772×10^{6}  BB[over ¯] events, recorded at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The obtained results are consistent with standard model expectations.

Evidence for X(3872)→J/ψπ^{+}π^{-} Produced in Single-Tag Two-Photon Interactions

We report the first evidence for X(3872) production in two-photon interactions by tagging either the electron or the positron in the final state, exploring the highly virtual photon region. The search is performed in e^{+}e^{-}→e^{+}e^{-}J/ψπ^{+}π^{-}, using 825  fb^{-1} of data collected by the Belle detector operated at the KEKB e^{+}e^{-} collider. We observe three X(3872) candidates, where the expected background is 0.11±0.10 events, with a significance of 3.2σ. We obtain an estimated value for Γ[over ˜]_{γγ}B(X(3872)→J/ψπ^{+}π^{-}) assuming the Q^{2} dependence predicted by a cc[over ¯] meson model, where -Q^{2} is the invariant mass squared of the virtual photon. No X(3915)→J/ψπ^{+}π^{-} candidates are found.

Incidence and Characteristics of Coronary Artery Spasms Related to Atrial Fibrillation Ablation Procedures - Large-Scale Multicenter Analysis

BACKGROUND

Coronary artery spasms (CASs), which can cause angina attacks and sudden death, have been recently reported during catheter ablation. The aim of the present study was to report the incidence, characteristics, and prognosis of CASs related to atrial fibrillation (AF) ablation procedures.Methods and Results:The AF ablation records of 22,232 patients treated in 15 Japanese hospitals were reviewed. CASs associated with AF ablation occurred in 42 of 22,232 patients (0.19%). CASs occurred during ablation energy applications in 21 patients (50%). CASs also occurred before ablation in 9 patients (21%) and after ablation in 12 patients (29%). The initial change in the electrocardiogram was ST-segment elevation in the inferior leads in 33 patients (79%). Emergency coronary angiography revealed coronary artery stenosis and occlusions, which were relieved by nitrate administration. No air bubbles were observed. A comparison of the incidence of CASs during pulmonary vein isolation between the different ablation energy sources revealed a significantly higher incidence with cryoballoon ablation (11/3,288; 0.34%) than with radiofrequency catheter, hot balloon, or laser balloon ablation (8/18,596 [0.04%], 0/237 [0%], and 0/111 [0%], respectively; P<0.001). CASs most often occurred during ablation of the left superior pulmonary vein. All patients recovered without sequelae.

CONCLUSIONS

CASs related to AF ablation are rare, but should be considered as a dangerous complication that can occur anytime during the periprocedural period.

Impact of Longer Hemodialysis Vintage with Higher Serum Phosphorus Level on Clinical Outcomes in Patients with Chronic Limb-Threatening Ischemia Presenting Tissue Loss after Endovascular Therapy

Aims: Hemodialysis vintage and serum phosphorus levels adversely affect outcomes in patients on hemodialysis. Whether these factors have a similar prognostic impact on patients who are on hemodialysis and have chronic limb-threatening ischemia (CLTI) has not been systematically studied. We aimed to explore the risk factors, including hemodialysis vintage and serum phosphorus levels, on clinical outcomes after endovascular therapy (EVT) in hemodialysis patients with CLTI.

Methods: The current study rerospectively analyzed 374 hemodialysis patients with CLTI presenting with ischemic tissue loss (age: 72.3±9.0 years, male: 73.3%, diabetes mellitus: 68.2%, Rutherford 5: 75.9%, 6: 24.1%, WIfI stage 4: 50.0%) primarily treated with EVT between April 2007 and December 2016. The primary outcome measure was 1-year amputation-free survival (AFS), while the secondary outcome measure was 1-year wound healing. Predictors for each outcome were evaluated by Cox proportional hazards model.

Results: Multivariate analysis significantly associated longer hemodialysis vintages with higher serum phosphorus levels (hazard ratio [HR], 0.599; 95% confidence interval [CI], 0.394-0.910; p =0.016) with 1-year AFS. Longer vintages for hemodialysis with higher serum phosphorus levels were marginally, but not significantly, associated with 1-year wound healing. (HR, 0.684; 95% CI, 0.467–1.000; p =0.050).

Conclusion: Longer hemodialysis vintages with higher serum phosphorus levels adversely affect outcomes after EVT for hemodialysis patients with CLTI presenting with ischemic tissue loss.

Evaluation of vascular anatomy for colon cancer located in the splenic flexure using the preoperative three-dimensional computed tomography angiography with colonography

PURPOSE

The aim of this study is to reveal the vascular branching variation in SFC (splenic flexure cancer) patients using the preoperative three-dimensional computed tomography angiography with colonography (3D-CTAC).

METHODS

We retrospectively analyzed patients with SFC who underwent preoperative 3D-CTAC between January 2014 and December 2019.

RESULTS

Among 1256 colorectal cancer (CRC) patients, 96 (7.6%) manifested SFC. The arterial branching from the superior mesenteric artery (SMA) was classified into five patterns, as follows: (type 1A) the left branch of middle colic artery (LMCA) diverged from middle colic artery (MCA) (N = 47, 49.0%); (2A) the LMCA diverged from the MCA and the accessory middle colic artery (AMCA) (N = 26, 27.1%); (3A) the LMCA independently diverged from the SMA (N = 16, 16.7%); (4A) the LMCA independently diverged from the SMA and AMCA (N = 3, 3.1%); (5A) only the AMCA and the LMCA was absent (N = 4, 4.1%). Venous drainage was classified into four patterns, as follows: (type 1V) the SFV flows into the inferior mesenteric vein (IMV) then back to the splenic vein (N = 50, 52.1%); (2V) the SFV flows into the IMV then back to the superior mesenteric vein (SMV) (N = 19, 19.8%); (type 3V) the SFV independently flows into the splenic vein (N = 3, 3.1%); (type 4V) the SFV is absent (N = 24, 25.0%).

CONCLUSION

3D-CTAC could reveal accurate preoperative tumor localization and vascular branching. These classifications should be helpful in performing accurate complete mesocolic excision and central vessel ligation for SFC.

Application and outcomes of a standardized lymphadenectomy in laparoscopic right hemicolectomy requiring ligation of the middle colic artery

BACKGROUND

Complete mesocolic excision with central vessel ligation may be important for accurate staging and improving the prognosis of right-sided colon cancer. Although the procedure is often performed laparoscopically, approaching the middle colic artery (MCA) is technically demanding, especially when complete ligation of arteries at their roots is desired. We standardized our laparoscopic approach by establishing the dissection boundary along the superior mesenteric artery to achieve D3 lymphadenectomy in the region of the MCA. The aim of the present study was to evaluate, on the basis of perioperative and short-term oncologic outcomes, the feasibility and safety of our technique METHODS: We conducted a retrospective study on consecutive patients with cancer located at the ascending colon and transverse colon who had laparoscopic right hemicolectomy requiring ligation of the MCA.

RESULTS

There were 41 patients (22 males, median age 71 years [range 49-86] years). The median operation time was 285 min, and blood loss volume was 40 mL. Conversion to open surgery was required in 1 case. Complications that were Clavien-Dindo grade III or above occurred in 3 patients (7.3%). There was no anastomotic leakage. The median number of lymph nodes harvested was 46.

CONCLUSIONS

Our technique was shown to be a safe, feasible, and useful strategy for performance of right hemicolectomy requiring ligation of the MCA in cases of colon cancer. The technique facilitates maximal lymph node dissection. Having obtained favorable outcomes, we look forward to investigation into long-term outcomes.

Two-Year Clinical Outcomes of Biodegradable Polymer vs. Durable Polymer Drug-Eluting Stent Implantation in Patients With End-Stage Renal Disease on Dialysis

Background: There are limited data comparing clinical outcomes between biodegradable polymer and durable polymer drug-eluting stents (BP-DES and DP-DES, respectively) in patients with end-stage renal disease (ESRD).

Methods and Results: This study enrolled 229 ESRD patients who underwent successful percutaneous coronary intervention (PCI) for 400 lesions with 472 DES, with 2-year clinical outcomes compared between the BP-DES and DP-DES groups. The primary outcome measure was the incidence of target lesion revascularization (TLR), whereas secondary outcome measures were the occurrence of cardiac death (CD), myocardial infraction (MI), stent thrombosis (ST), target vessel revascularization (TVR), non-TVR, and major adverse cardiac events (MACE), defined as a composite of CD, MI, and TVR. Multivariate analysis was used to identify predictors of TLR occurrence. The 2-year incidence of TLR did not differ significantly between the BP-DES and DP-DES groups (P=0.274). In addition, there were no significant differences in the 2-year incidence of CD (P=0.144), MI (P=0.812), ST (P=0.241), TVR (P=0.434), non-TVR (P=0.375), or MACE (P=0.841) between the 2 groups. Multivariate analysis showed that diabetes (P=0.021) was independently associated with TLR occurrence.

Conclusions: BP-DES and DP-DES had comparable safety and efficacy profiles over a 2-year follow-up period after PCI in ESRD patients.

Angioscopic assessments and clinical outcomes one year after polymer-free biolimus A9-coated coronary stent implantation

BACKGROUND

Polymer-free biolimus A9-coated coronary stent (DCS) has novel features which lead to the expectation of better arterial healing. However, comparisons of intravascular status between DCS and drug-eluting stents (DES), and robust real-word clinical assessments of DCS have been lacking to date.

METHODS

From September 2017 to September 2018, we evaluated the intra-vascular status of 74 DCS implanted in 55 lesions from 43 patients using coronary angioscopy (CAS) approximately one year after implantation from a cohort of 219 lesions in 158 patients. We set 239 second-generation durable-polymer DES (DP-DES) implanted in 211 lesions from 180 patients from a cohort of 2652 lesions in 1914 patients as the control. Angioscopic images were analyzed to determine (1) the dominant degree of neointimal coverage (NIC) over the stent; (2) the heterogeneity of NIC; (3) yellow color grade of the stented segment; and (4) the presence of intra-stent thrombus. The primary outcome was the incidence of thrombus and secondary outcomes were the other CAS findings, and the 1-year clinical outcomes which included target lesion revascularization (TLR) and major adverse cardiac events (MACE). To minimize inter-group differences in baseline characteristics, propensity score matching was performed for clinical outcomes.

RESULTS

Incidence of thrombus adhesion was similar in DCS and DP-DES groups (28.4% versus 22.6%, p=0.31). However, the dominant NIC grade was significantly higher in DCS (p<0.001), while NIC was more heterogeneous in DCS than in DP-DES (p=0.001). Maximum yellow color grade was similar (p=0.22). After propensity score matching, 202 lesion pairs from 146 patient pairs were retained for analysis. The cumulative incidence of TLR (4.6% versus 3.8%, p=0.38) and MACE (11.6% versus 11.7%, p=0.84) was similar for DCS and DP-DES.

CONCLUSIONS

DCS showed thrombus adhesion and clinical outcomes at 1 year similar to DP-DES. DCS can thus be used with similar safety and efficacy as DP-DES.

Search for Axionlike Particles Produced in e^{+}e^{-} Collisions at Belle II

We present a search for the direct production of a light pseudoscalar a decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process e^{+}e^{-}→γa, a→γγ in the mass range 0.2<m_{a}<9.7  GeV/c^{2} using data corresponding to an integrated luminosity of (445±3)  pb^{-1}. Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling strength g_{aγγ} of ALPs to photons at the level of 10^{-3}  GeV^{-1}. The limits are the most restrictive to date for 0.2<m_{a}<1  GeV/c^{2}.

High Brain Natriuretic Peptide Level Predicts The Prevalence Of Low-Voltage Areas And Poor Rhythm Outcome In Patients Undergoing Atrial Fibrillation Ablation

Backgrounds

The prevalence of residual left atrial low-voltage areas (LVAs) is associated with atrial fibrillation (AF) recurrence after pulmonary vein isolation. Brain natriuretic peptide (BNP) may be increased in AF patients and may raise AF recurrence risk after catheter ablation. We investigated the association between BNP and the prevalence of LVAs.

Methods

One hundred and eighty three consecutive AF cases were retrospectively enrolled that underwent initial ablation for AF (persistent AF, 82 [45%] patients). Serum BNP was measured before ablation and the natural logarithm of BNP (log-BNP) was calculated. Low-voltage points were defined as sites with left atrial electrogram amplitude <0.5 mV. LVAs were defined as regions with ≥5% low-voltage points across the total surface area of the left atrium.

Results

Of the 183 patients, 38 (21%) had LVAs. Patients with LVAs demonstrated higher log-BNP (4.8±0.9 vs. 3.9±1.2, P<0.001). The optimal cut-off value of log-BNP was 4.4, which was equivalent to 81 pg/mL of BNP. LVAs were more frequent in patients with higher log-BNP. In multivariate analysis, log-BNP >4.4 was an independent predictor of LVAs (odds ratio 2.7 [95% confidence interval 1.01-7.1], P=0.048). Freedom from AF recurrence was significantly lower in patients with than without high log-BNP (P=0.007).

Conclusions

BNP correlated with the prevalence of left atrial LVAs and AF recurrence in patients with AF undergoing catheter ablation.

A new clinical risk score for predicting the prevalence of low-voltage areas in patients undergoing atrial fibrillation ablation

INTRODUCTION

Although the presence of left atrial low-voltage areas (LVAs) is strongly associated with the recurrence of atrial fibrillation (AF) after ablation, few methods are available to classify the prevalence of LVAs. The purpose of this study was to establish a risk score for predicting the prevalence of LVAs in patients undergoing ablation for AF.

METHODS

We enrolled 1004 consecutive patients who underwent initial ablation for AF (age, 68 ± 10 years old; female, 346 (34%); persistent AF, 513 (51%)). LVAs were deemed present when the voltage map after pulmonary vein isolation demonstrated low-voltage areas with a peak-to-peak bipolar voltage of <0.5 mV covering ≥5 cm² of the left atrium.

RESULTS

LVAs were present in 206 (21%) patients. The SPEED score was obtained as the total number of independent predictors as identified on multivariate analysis, namely female sex (odds ratio [OR], 3.4 [95% confidence interval {CI} 2.2-5.2], p < .01), persistent AF (OR, 1.8 [95% CI, 1.1-3.0], p = .02), age ≥ 70 years (OR, 2.3 [95% CI, 1.5-3.4], p < .01), elevated brain natriuretic peptide ≥100 pg/ml or N-terminal probrain natriuretic peptide ≥400 pg/ml (OR, 1.7 [95% CI, 1.02-2.8], p = .04), and diabetes mellitus (OR, 1.8 [95% CI, 1.1-2.8], p = .02). LVAs were more frequent in patients with a higher SPEED score, and prevalence increased with each additional SPEED score point (OR, 2.4 [95% CI, 2.0-2.8], p < .01).

CONCLUSION

The SPEED score accurately predicts the prevalence of LVAs in patients undergoing ablation for AF.

Low-Voltage Areas as Alternative Targets for the Ablation of Unmappable Atrial Tachycardia in Patients Undergoing Atrial Fibrillation Ablation

Aims

Unmappable regular atrial tachycarrhythmias (ATs) occasionally develop during atrial fibrillation (AF) ablation, and are difficult to treat by conventional ablation. Recently, low-voltage areas (LVAs) have been reported to represent AT substrate. The purpose of this study was to elucidate the efficacy of LVA ablation for unmappable AT.

Methods

This observational study included 32 consecutive patients who developed unmappable ATs during and after AF ablation. Unmappable AT was defined as AT lasting for >5 s, but that terminated or changed the activation sequence over too short a time to create a sufficient activation map. We used conventional ablation to target undetermined AT circuits estimated from activation timings of electrograms recorded on the placed electrode catheter, the response to entrainment mappings, and/or diastolic potentials during AT. Subsequently, in cases without successful elimination of unmappable ATs by conventional ablation, LVA (≤ 0.5 mV) ablation was performed at the discretion of the operators.

Results

Conventional ablation failed to eliminate at least one unmappable AT in 29 patients. Among them, LVA ablation was performed in 16 patients. LVA ablation eliminated all the unmappable ATs in 8 of 16 patients. The LVA size did not differ between patients with and without the acute elimination of unmappable ATs (17±11 vs. 21±12 cm2, p = 0.39), and AT/AF recurrence rates were comparable between the two groups (38% vs. 63%, p = 0.62) during a mean follow-up period of 14±8 months.

Conclusions

LVA ablation was efficacious to some extent for the elimination of unmappable ATs refractory to conventional ablation.

Impact of the Temporal Relationship Between Atrial Fibrillation and Heart Failure on Prognosis After Ablation

BACKGROUND

The purpose of this study was to elucidate the effect of the temporal relationship between atrial fibrillation (AF) and heart failure (HF) on clinical outcomes after catheter ablation.Methods and Results:We included 129 consecutive patients with AF and HF who underwent catheter ablation in hospital from December 2014 to September 2017. The patients were divided into 2 groups based on the temporal relationship between AF and HF. Group 1 consisted of 42 patients with AF following HF while Group 2 consisted of 87 patients with AF preceding HF or those who developed both of them simultaneously at the timing of first visit to a doctor. The primary endpoint was a composite of death and hospitalization due to HF during a 2-year follow-up. AF recurrence was more common in Group 1 (45% vs. 23%; hazard ratio [HR], 2.49; 95% confidence interval [CI], 1.25-4.94; P=0.009). Death and HF hospitalization were more frequent in Group 1 (19 [45%], 6 [7%] patients, respectively, P<0.0001). After adjustment for several covariates, patients in Group 1 were independently associated with poorer outcomes after AF ablation (HR, 8.66; 95% CI, 2.942-5.5; P<0.0001).

CONCLUSIONS

Adverse clinical outcomes of death, HF hospitalization and AF recurrence were more frequent in patients with AF following HF than in those with AF preceding HF.

Comparison of Long-Term Outcomes Between Combination Antiplatelet and Anticoagulant Therapy and Anticoagulant Monotherapy in Patients With Atrial Fibrillation and Left Atrial Thrombi

Background: Anticoagulation for patients with atrial fibrillation (AF) complicated by left atrial thrombi (LAT) is a frequent cause of bleeding complications, but risk factors remain unknown.

Methods and Results: Of 3,139 AF patients who underwent transesophageal echocardiography, 82 with LAT under anticoagulation were included in this study. Patients treated with combination antiplatelet and anticoagulant therapy (n=31) were compared with those receiving anticoagulant monotherapy (n=51) to investigate the effects of antiplatelet agents during anticoagulation on bleeding complications. Over a mean (±SD) follow-up of 878±486 days, bleeding events occurred more frequently in the combination therapy than monotherapy group (58% vs. 20%; P<0.001), but there was no significant difference in embolic events (6.5% vs. 3.9%; P=0.606). Kaplan-Meier analysis also showed a significantly higher rate of bleeding events in the combination therapy group, but no significant difference in the rate of embolic events. Inverse probability of treatment weighting revealed that combination therapy was independently associated with an increased risk of bleeding (hazard ratio [HR] 2.98, 95% confidence interval [CI] 1.14–7.89, P=0.026), but not with the risk of embolic events (HR 0.30, 95% CI 0.04–2.59, P=0.275). Net clinical benefit analysis was almost negative for combination therapy vs. monotherapy.

Conclusions: In patients with AF and LAT, combination therapy was significantly associated with an increased risk of bleeding events, but not with a reduced risk of embolic events.

Risk Stratification for 2-Year Mortality in Patients with Chronic Limb-Threatening Ischemia Undergoing Endovascular Therapy

AIM

The latest Global Vascular Guidelines (GVG) recommend assessing the 2-year mortality risk in patients with chronic limb-threatening ischemia (CLTI) before revascularization. This study aimed to reveal whether the Wound, Ischemia and foot Infection (WIfI) classification, developed originally as a risk assessment tool for limb prognosis, would be useful in predicting the 2-year mortality risk in patients with CLTI in the era of GVG and WIfI.

METHODS

We retrospectively analyzed 849 patients with CLTI who were primarily treated with endovascular therapy (EVT) between April 2010 and December 2016. The impact of baseline characteristics, including the WIfI classification on mortality risk, was investigated using the Cox proportional hazards regression model.

RESULTS

During a mean follow-up of 19.3 months, 243 deaths were observed. The 2-year mortality rate was 32.3%. Multivariate analysis demonstrated that WIfI classification stages (p=0.037), in addition to male sex (p=0.010), age (p＜0.001), non-ambulatory status (p＜0.001), body mass index (p=0.002), and hemodialysis (p＜0.001), were independent predictors for an increased risk of mortality, while the Rutherford classification was not.

CONCLUSIONS

WIfI classification stages were independently associated with mortality risk in patients with CLTI undergoing EVT, while the Rutherford classification was not. The WIfI classification would be a practical tool for planning the revascularization strategy in CLTI treatment.

Clinical utility of local impedance monitoring during pulmonary vein isolation

INTRODUCTION

Local impedance (LI) at the tip of ablation catheter can be measured using a recently available technology. We aimed to explore target LI measurements at each radiofrequency application (RFA) for creating sufficient ablation lesions during pulmonary vein (PV) isolation.

METHODS

This prospective study included 15 consecutive patients scheduled to undergo an initial ablation of paroxysmal atrial fibrillation (AF). Circumferential ablation around both ipsilateral PVs was performed using a 4-mm irrigated ablation catheter with an LI sensor. Point-by-point ablation was used with a 4-mm inter-ablation-point distance. Operators were blinded to LI measurements during the procedure. Creation of sufficient ablation lesions was assessed by the absence of a conduction gap.

RESULTS

After first-pass encircling PV antrum ablation, left atrium to PV conduction remained in 12 of 30 (40%) ipsilateral PVs. Mapping using the minibasket catheter identified 48 ablation points through which the propagation wave entered the PV. At ablation points with a gap, the LI drop during RFA was half that at points without a gap (12 ± 7 vs. 23 ± 12 Ω; p < .001). The generator impedance drop did not differ between ablation points with and without a gap (12 ± 7 vs. 14 ± 10  Ω; p = .10). An LI drop of 13.4 Ω predicted sufficient lesion formation without a gap with a sensitivity of 0.78, specificity of 0.75, and predictive accuracy of 0.75.

CONCLUSION

An LI drop of 13.4 Ω at each RFA under the conditions of a 4-mm inter-ablation-point distance and RFA duration ≥20 s may facilitate creation of sufficient lesions during PV isolation.

Additional Low-Voltage-Area Ablation in Patients With Paroxysmal Atrial Fibrillation: Results of the Randomized Controlled VOLCANO Trial

Background The efficacy of low-voltage-area (LVA) ablation has not been well determined. This study aimed to investigate the efficacy of LVA ablation in addition to pulmonary vein isolation on rhythm outcomes in patients with paroxysmal atrial fibrillation (AF). Methods and Results VOLCANO (Catheter Ablation Targeting Low-Voltage Areas After Pulmonary Vein Isolation in Paroxysmal Atrial Fibrillation Patients) trial included paroxysmal AF patients undergoing initial AF ablation. Of 398 patients in whom a left atrial voltage map was obtained after pulmonary vein isolation, 336 (85%) had no LVA (group A). The remaining 62 (15%) patients with LVAs were randomly allocated to undergo LVA ablation (group B, n=30) or not (group C, n=32) in a 1:1 fashion. Primary end point was 1-year AF-recurrence-free survival rate. No adverse events related to LVA ablation occurred. Procedural (124±40 versus 95±33 minutes, P=0.003) and fluoroscopic times (29±11 versus 24±8 minutes, P=0.034) were longer in group B than group C. Patients with LVAs demonstrated lower AF-recurrence-free survival rates (88%) than those without LVA (B, 57%, P<0.0001; C, 53%, P<0.0001). However, LVA ablation in addition to pulmonary vein isolation did not impact AF-recurrence-free survival rate (group B versus C, P=0.67). Conclusions The presence of LVA was a strong predictor of AF recurrence after pulmonary vein isolation in patients with paroxysmal AF. However, LVA ablation had no beneficial impact on 1-year rhythm outcomes. Registration URL: https://www.umin.ac.jp/ctr; Unique identifier: UMIN000023403.