Tomofumi Nakamura

Prognostic implications of chronic kidney disease and anemia after percutaneous coronary intervention in acute myocardial infarction patients

Anemia is a common complication of chronic kidney disease (CKD), and a few studies suggest that both CKD and anemia have a marked impact on the prognosis of patients with cardiovascular disease. We retrospectively analyzed the prevalence of CKD and anemia in 312 patients with acute myocardial infarction (AMI). The patients were divided into four groups according to the presence of CKD and anemia. Chronic kidney disease was defined as estimated glomerular filtration rate <60 ml/min/1.73 m2, and anemia was defined according to the World Health Organization definition. Of 312 AMI patients, 166 (53.2%) had CKD and 87 (27.8%) had anemia. A powerful relationship was observed between both CKD and anemia and major adverse cardiac and cerebrovascular events (MACCE) or death by any cause. After adjustment for comorbidities, the hazard ratio (HR) for MACCE was significantly higher in the anemia-only group (HR 5.42, 95% confidence interval (CI) 1.38–21.27, P = 0.015), the CKD-only group (HR 6.4, 95% CI 2.09–19.58, P = 0.001), and the CKD and anemia group (HR 11.61, 95% CI 3.65–36.89, P < 0.001). With respect to death by any cause, the HR was significantly higher in the CKD-only group (HR 2.68, 95% CI 1.02–7.02, P = 0.045) and the CKD and anemia group (HR 4.40, 95% CI 1.56–12.43, P = 0.005). One-half of the patients with AMI had CKD as well. Furthermore, when anemia coexisted with CKD, these conditions had a multiplicative amplification effect on the risk of MACCE and death by any cause in patients with AMI.

Bleeding events and activated partial thromboplastin time with dabigatran in clinical practice

BACKGROUND Dabigatran has demonstrated promising results for the prevention of strokes in patients with non-valvular atrial fibrillation (NVAF). However, there have been episodes of major bleeding, especially in elderly patients or those with renal dysfunction. The purpose of this study was to retrospectively examine the relationship between the bleeding events and activated partial thromboplastin time (APTT) values under dabigatran usage in the everyday clinical practice. Moreover, we investigated which factors would contribute to the APTT values. METHODS AND RESULTS A total of 139 NVAF patients (112 men, 65 ± 11 years) were included. We evaluated the influence of the putative etiological variables and the bleeding score, HAS-BLED score, on APTT values: age greater than 70 years, renal function, gender, dose of dabigatran, and the concomitant prescription of a P-glycoprotein inhibitor. There were 50 patients with an age of ≥ 70 years (36.0%). A P-glycoprotein inhibitor was administered in 18 patients. During the observation period (median 120 days) there was 1 episode of asymptomatic cerebral infarction. There were no intrinsic major bleeding events, however, 11 patients had minor hemorrhagic events. The results of the APTT measurements exhibited a variety of values both among inter- and intra-individuals. On multivariable analysis, significant associations were found between the following risk factors and the APTT values: creatinine clearance, dose of dabigatran, and concomitant use of a P-glycoprotein inhibitor. The minor bleeding events did not correlate with the APTT values, nor HAS-BLED score. CONCLUSIONS The APTT values became prolonged under dabigatran usage and exhibited a remarkable diversity. Although major bleeding did not occur unless APTT was prolonged excessively, minor bleeding arose irrespective of the APTT values even within the range of the APTT values not exceeding 80s.

Novel method for earlier detection of phrenic nerve injury during cryoballoon applications for electrical isolation of pulmonary veins in patients with atrial fibrillation

BACKGROUND Diaphragmatic electrogram recording during cryoballoon ablation (CB-A) of atrial fibrillation is commonly used to predict phrenic nerve palsy (PNP). OBJECTIVE The purpose of this study was to investigate a novel method for predicting PNP at an earlier stage to prevent sustained PNP. METHODS A total of 197 patients undergoing CB-A were enrolled. We attempted to detect PNP using fluoroscopic images of diaphragmatic contractions and by monitoring diaphragmatic compound motor action potentials (CMAPs) provoked by superior vena cava (SVC) and left subclavian vein (LCV) pacing during CB-A for bilateral pulmonary veins (PVs). Pacing of the SVC and LCV was performed at 2 outputs, 1 exceeding the pacing threshold by 10% (MIN) and the other at maximum output (MAX). The time from freezing to the initiation of PNP, values of the CMAP amplitude, and severity of PNP were compared for the 2 outputs. RESULTS There was a significant difference in the time from freezing to initiation of PNP between MIN and MAX pacing (25.7 ± 5.7 vs 81.3 ± 7.4 seconds, P<.01). CMAP amplitudes also differed significantly (0.71 ± 0.39 vs 1.13 ± 0.42, P<.0001). SVC/LCV pacing with MIN output was able to detect PNP significantly earlier than MAX (27 ± 8 vs 91 ± 12 seconds, P<.01), and the time to PNP recovery was significantly shorter for the MIN output (20.2 ± 8.88 hours vs 4.8 ± 1.6 months, P<.001). CONCLUSION Pacing the SVC and LCV with lower output detect PNP significantly earlier than maximal output pacing and leads to recovery from PNP on the order of hours postprocedure rather than months.

Comparative study of hemorrhagic and ischemic complications among anticoagulants in patients undergoing cryoballoon ablation for atrial fibrillation

OBJECTIVE Few data exist to evaluate the safety and efficacy of direct oral anticoagulants (DOACs) in patients with atrial fibrillation (AF) undergoing cryoballoon ablation (CB-A). This study is aimed to clarify the usefulness of DOACs in patients undergoing CB-A. METHODS The patients (average age; 65.8±11.9 years old, male 69%) were stratified into one of five subsets based on the type of anticoagulation (warfarin, apixaban, dabigatran, rivaroxaban, or edoxaban), and underwent CB-A. A brain MRI was performed in all patients the day after the CB-A for AF. A total of 257 (19 on warfarin, 30 on apixaban, 66 on dabigatran, 81 on rivaroxaban, and 61 on edoxaban) patients met the inclusion criteria. RESULTS The incidence of silent cerebral ischemic lesion was 1 (11.1%) patients on warfarin, 5 (33.3%) on apixaban, 8 (27.6%) on dabigatran, 10 (21.3%) on rivaroxaban, and 10 (29.4%) on edoxaban (p=0.17). Major ischemic events occurred in one patient (1.6%) on edoxaban and one (5.3%) on warfarin. Minor bleeding complications occurred in 1 patient (5.3%) on warfarin, 2 (6.7%) on apixaban, 1 (1.2%) on rivaroxaban, 5 (7.6%) on dabigatran, and 2 (3.3%) on edoxaban (p=0.24). Of note, major bleeding complications occurred in 2 patients (3.3%) on apixaban, 1 (1.2%) on rivaroxaban, 1 (1.5%) on dabigatran, 1 (1.6%) on edoxaban, and 2 (10.5%) on warfarin (p<0.05). CONCLUSIONS Warfarin use significantly increased the risk of serious bleeding, in contrast, CB-A did not place the patients at an increased risk of complications under a DOAC treatment. There were no significant differences regarding preventing embolic events among the DOAC drugs.

Clinical assessment of cryoballoon ablation in cases with atrial fibrillation and a left common pulmonary vein

Pulmonary vein isolation (PVI) using a cryoballoon (CB) is a useful tool for treating atrial fibrillation (AF); however, the clinical efficacy of the CB has never been fully investigated in patients with a left common pulmonary vein (LCPV).

The Relationship between the Profiles of SVC and Sustainability of SVC Fibrillation Induced by Provocative Electrical Stimulation.

Superior vena cava (SVC) can be a focus of atrial fibrillation (AF). However, distinctive features that identify SVC arrhythmogenicity remain unclear. Sustainability of fibrillation within the SVC might help with identifying SVC arrhythmogenicity. The purpose of this study was to investigate the relationship between the anatomical and electrical profiles of SVC and sustainability of SVC fibrillation induced by proactive electrical stimulation.

Characteristics of dormant pulmonary vein conduction induced by adenosine triphosphate in patients with atrial fibrillation undergoing cryoballoon ablation

BACKGROUND Adenosine triphosphate (ATP) can provoke acute reconnections after pulmonary vein isolation (PVI). This study aimed to investigate dormant conduction (DC) after ablation with second-generation cryoballoon (CB). METHODS Two hundred sixteen patients (148 male; age 64±9 years) with atrial fibrillation (AF) were included. After a successful PVI with the CB, 20mg of ATP was administered. All patients were followed up for 425±56 days. RESULTS Seven hundred ninety-five out of 864 (92%) PVs were successfully isolated solely by the CB. DCs were revealed in 8 (3.7%) after ATP injections. AF recurrences occurred in 2 out of 8 patients, while no AF recurrences could be documented in 6 out of 8 patients with DCs after a blanking period of 3 months (25% vs. 75%). In contrast, 29 (13.9%) patients without DCs had AF recurrences, and there was no significant difference between those with and without DCs regarding the recurrence rate of AF (p=0.38). There were no reliable predictors of DCs after the PVI with the CB. CONCLUSION The present study demonstrated a low rate of transient PV reconnection after adenosine infusion following successful PVI with the CB. There was no reliable predictor of DCs. Further studies will be needed in order to appreciate the prognostic value of adenosine testing after successful PVI with the CB.

The impact of B-type natriuretic peptide levels on the suppression of accompanying atrial fibrillation in Wolff-Parkinson-White syndrome patients after accessory pathway ablation

BACKGROUND Atrial fibrillation (AF) often coexists with Wolff-Parkinson-White (WPW) syndrome. We compared the efficacy of Kent bundle ablation alone and additional AF ablation on accompanying AF, and examined which patients would still have a risk of AF after successful Kent bundle ablation. METHODS This retrospective multicenter study included 96 patients (56±15 years, 72 male) with WPW syndrome and AF undergoing Kent bundle ablation. Some patients underwent simultaneous pulmonary vein isolation (PVI) for AF. The incidence of post-procedural AF was examined. RESULTS Sixty-four patients underwent only Kent bundle ablation (Kent-only group) and 32 also underwent PVI (+PVI group). There was no significant difference in the basic patient characteristics between the groups. Additional PVI did not improve the freedom from residual AF compared to Kent bundle ablation alone (p=0.53). In the Kent-only group, AF episodes remained in 25.0% during the follow-up (709 days). A univariate analysis showed that age ≥60 years, left atrial dimension ≥38mm, B-type natriuretic peptide (BNP) ≥40pg/ml, and concomitant hypertension were predictive factors for residual AF. However, in the multivariate analysis, only BNP ≥40pg/ml remained as an independent predictive factor (HR=17.1 and CI: 2.3-128.2; p=0.006). CONCLUSIONS Among patients with WPW syndrome and AF, Kent bundle ablation alone may have a sufficient clinical impact of preventing recurrence of AF in select patients. Screening the BNP level would help decide the strategy to manage those patients.

Coronary Sinus Stenosis as Collateral Damage of Radiofrequency Ablation in Patients With Atrial Fibrillation

A 72-year-old man with atrial fibrillation (AF) that persisted for more than 10 years underwent catheter ablation. All pulmonary veins were isolated by cryoballoon ablation, as previously described [(1,2)][1]. Subsequently, conduction block line (CBL) construction at the mitral isthmus was attempted

Three-dimensional electroanatomical mapping for atrioventricular nodal reentrant tachycardia associated with persistent left superior vena cava

The anatomical courses of the slow pathway and His bundle are altered in patients with atrioventricular nodal reentrant tachycardia (AVNRT) associated with persistent left superior vena cava (PLSVC). We report a case of successful catheter ablation in such a patient using an electroanatomical approach with a three‐dimensional mapping system.