P4764Relationship of the duration of pulmonary vein isolation-refractory non-paroxysmal atrial fibrillation to the middle- to long-term outcome of the ExTRa Mapping-guided ablation

Introduction

It is reported that for patients with non-paroxysmal (persistent or long-standing persistent) atrial fibrillation (Non-PAF), extended ablation to atrial walls in addition to pulmonary vein isolation (PVI) did not improve the long-term outcome. On the other hand, modulation of Non-PAF drivers (or perpetuators) has been proposed as one of the alternative effective ablation strategies for Non-PAF.

Purpose

To clarify whether the rotor ablation under online real-time high-density phase mapping system is effective for PVI-refractory Non-PAF ablation.

Methods

Under such circumstances, our academic group had recently developed the online real-time high-density phase mapping system (ExTRa Mapping™) by industrial alliance. The phase map moving images were based on 41 intra-atrial bipolar signals recorded by a 20-pole spiral-shaped catheter (2.5 cm in diameter) and on in silicorapid prediction of spatio-temporal atrial excitations (artificial intelligence system). Then we applied the ExTRa Mapping to clinical practice in order to directly visualize rotors in patients with Non-PAF, and investigated the middle- to long-term outcome of the ExTRa Mapping-guided rotor ablation (ExTRa-ABL).

Results

Thirty-eight patients (63±8 y/o, 30 males) with Non-PAF demonstrating refractoriness to PVI were enrolled in this study. Ablation for cavo-tricuspid isthmus and/or superior vena cava isolation was additionally performed at physicians' discretion. After these procedures, the ExTRa-ABL was performed in order to modify Non-PAF substrates, causing rotor control. The modification of the rotors was evaluated by re-mapping with the use of the ExTRa Mapping at the end of each ablation session. Patients were followed at 1, 3, 6 months and every year after the procedure. All of them were followed for 21±8 months. During the follow-up period, Non-PAF was recurred in only 8 of 38 (21%). Furthermore, we found if PVI-refractory Non-PAF duration was shorter than 6 years, the non-recurrence rate remained ≥80% (see Figure), which was markedly better outcome comparing with previous reports with regard to Non-PAF ablation.

Figure 1

Conclusion

Comparing with conventional Non-PAF ablation strategies, our novel approach with the use of the online real-time high-density phase mapping system might improve medium- to long-term outcome of PVI-refractory Non-PAF treatment.

4968Increased Gao expression underlies cardiac dysfunction and lethal arrhythmias accompanied with abnormal Ca2+ handling

Background

We previously demonstrated that a transcriptional repressor, neuron restrictive silencer factor (NRSF), maintains normal cardiac function and electrical stability. Transgenic mice expressing a dominant-negative mutant of NRSF in their hearts (dnNRSF-Tg) exhibit systolic dysfunction with cardiac dilation and premature death due to lethal arrhythmias like human dilated cardiomyopathy (DCM). Underlining mechanisms remain to be elucidated, however.

Purpose

We studied underling mechanisms by which NRSF maintains normal cardiac function to identify novel therapeutic targets for heart failure.

Methods and results

We generated cardiac-specific NRSF knockout mice (NRSFcKO) and confirmed that cardiac phenotypes of NRSFcKO are similar to those of dnNRSF-Tg.

cDNA microarray analysis revealed that cardiac gene expression of GNAO1 that encodes Gαo, a member of inhibitory G protein Gαi family, is increased in both dnNRSF-Tg and NRSFcKO ventricles.

We confirmed that GNAO1 is a direct target of NRSF through ChIP-seq analysis, reporter assay and electrophoretic mobility shift assay.

In dnNRSF-Tg, pharmacological inhibition of Gαo with pertussis toxin improved systolic dysfunction and knockdown of Gαo by crossing with GNAO1 knockout mice improved not only systolic function but also frequency of ventricular arrhythmias and survival rates.

Electrophysiological and biochemical analysis in ventricular myocytes obtained from dnNRSF-Tg demonstrated that genetic reduction of Gαo ameliorated abnormalities in Ca2+ handling, which include increased current density in surface sarcolemmal L-type Ca2+ channel, reduced content of sarcoplasmic reticulum Ca2+ and lowered peak of Ca2+ transient. Furthermore, genetic reduction of Gαo attenuated increased phosphorylation levels of CAMKII in dnNRSF-Tg ventricles, which presumably underlies the improvement in Ca2+ handling. In addition, we identified increased Gαo expression in ventricles of heart failure model mice induced by transverse aortic constriction and cardiac troponin T mutant DCM model mice, in both of which, genetic reduction of Gαo ameliorated cardiac dysfunction.

Figure 1

Conclusions

We found that increased expression of Gαo, induced by attenuation of NRSF-mediated repression, plays a crucial role in the progression of cardiac dysfunction and lethal arrhythmias by evoking Ca2+ handling abnormality. These data demonstrate that Gαo is a potential therapeutic target for heart failure.

P862Hypoxemia during sleep in patients with vasospastic angina

Background

Previous studies have shown the associations between sleep-disordered breathing (SDB) and vasospastic angina (VSA). However the characteristics of SDB related to VSA have been unknown.

Purpose

We investigate the characteristics of SDB in VSA patients, with focus on the role of nocturnal hypoxemia, which may trigger nocturnal ischemic attacks, typical attacks occurred during sleep in early morning.

Methods

We studied 33 patients who were diagnosed with VSA, based on diagnostic algorithm in the Japanese Circulation Society guidelines 2013 for VSA. All patients underwent polysomnography. Twenty one patients with moderate-severe SDB [apnea-hypopnea index (AHI) of at least 15/hour] diagnosed with polysomnography, but without cardiovascular diseases, were served as controls.

Results

Only 3 patients with VSA were free of SDB (AHI less than 5/hour). Moderate to severe SDB was found in 25 of 33 patients with VSA. These 25 patients were further studied. Daytime sleepiness assessed by the Epworth sleepiness scale, was lower in SDB patients with VSA than those without it (4.8±4.2 vs. 8.9±4.0; p=0.02). There were no differences in AHI between SDB patients with and without VSA (41.2±17.2/hour vs. 39.9±14.4/hour), but hypoxemic burden (time with oxygen saturation <90%) was higher in those with VSA than those without it [(median 20.7minitutes, interquartile range 6.4–48.0minitues) vs. median 5.9minitutes, interquartile range 3.9–11.0minitues); p=0.01]. In VSA patients, 39% of hypoxemia was observed in rapid eye movement (REM) periods of sleep, which accounts for only 18% of total sleep.

Conclusions

A high prevalence of moderate-severe SDB was found in VSA patient, although the symptoms were mild. Hypoxemia is a characteristic of SDB associated with VSA, which may be a target for therapeutic intervention in addition to drug therapy.

128Change in geriatric nutritional risk index predicts one-year mortality in patients with heart failure with preserved ejection fraction

Background

Malnutrition is associated with adverse prognosis in heart failure patients. However, in patients with heart failure with preserved ejection fraction (HFpEF), the effects of change in nutritional status during hospitalization on prognosis is unknown. Geriatric nutritional risk index (GNRI) is a widely used objective index for evaluating nutritional status. Low GNRI (<92) has moderate or severe nutritional risk and high GNRI (≥92) has no or low nutritional risk.

Purpose

The purpose of this study was to clarify the effect of change in GNRI during hospitalization on one-year mortality and the association between the value of GNRI and one-year mortality in patients with HFpEF.

Methods

We prospectively registered patients with HFpEF in PURSUIT-HFpEF registry when they were hospitalized for heart failure in 29 hospitals. Preserved ejection fraction was defined as more than 50% of left ventricular ejection fraction. Of the 486 patients who registered PURSUIT-HFpEF, 228 cases with one-year follow-up data were examined. GNRI was calculated as follows: 14.89 × serum albumin (g/dl) + 41.7 × body mass index/22.

Results

Mean age was 81±10 years and 100 patients (44%) were male. During a median [interquartile range] follow-up period of 374 [342, 400] days, 28 patients (12%) died. Mortality was significantly higher in patients with low GNRI at admission (n=65) than those with high GNRI at admission (n=163) (26% vs. 9%, log-rank P=0.011) and higher in patients with low GNRI at discharge (n=109) than those with high GNRI at discharge (n=119) (22% vs. 6%, log-rank P=0.002). Multivariate analysis with Cox proportional hazard model with patient characteristics at admission revealed that low GNRI at admission was independently associated with mortality (hazard ratio: 0.96, 95% CI: 0.93–0.99, P=0.035) and that with patient characteristics at discharge revealed that low GNRI at discharge was independently associated with mortality (hazard ratio: 0.94, 95% CI: 0.91–0.97, P<0.001). We also compared mortality by dividing patients into 4 group according to whether GNRI was high or low at the time of admission and discharge. Patients with low GNRI at admission and at discharge (n=59) exhibited the highest mortality, on the other hand, patients with high GNRI at admission and low GNRI at discharge (n=50) exhibited higher mortality than those with high GNRI both at admission and at discharge (n=113) (Low and low: 28% vs. High and low: 14% vs. High and high: 6% vs. Low and high: 0%, log-rank P=0.010).

All cause mortality

Conclusion

GNRI at admission or at discharge was independently associated with one-year mortality in patients with HFpEF. Moreover, worsening GNRI during hospitalization is associated with the worse prognosis. It is important to prevent lowering GNRI during treatment of acute decompensated HFpEF.

Acknowledgement/Funding

Roche Diagnostics, FUJIFILM Toyama Chemical

Minimally invasive spinal decompression for degenerative lumbar spondylolisthesis and stenosis maintains stability and may avoid the need for fusion

Aims

The aim of this study was to investigate the clinical and radiographic outcomes of microendoscopic laminotomy in patients with lumbar stenosis and concurrent degenerative spondylolisthesis (DS), and to determine the effect of this procedure on spinal stability.

Patients and Methods

A total of 304 consecutive patients with single-level lumbar DS with concomitant stenosis underwent microendoscopic laminotomy without fusion between January 2004 and December 2010. Patients were divided into two groups, those with and without advanced DS based on the degree of spondylolisthesis and dynamic instability. A total of 242 patients met the inclusion criteria. There were 101 men and 141 women. Their mean age was 68.1 years (46 to 85). Outcome was assessed using the Japanese Orthopaedic Association and Roland Morris Disability Questionnaire scores, a visual analogue score for pain and the Short Form Health-36 score. The radiographic outcome was assessed by measuring the slip and the disc height. The clinical and radiographic parameters were evaluated at a mean follow-up of 4.6 years (3 to 7.5).

Results

There were no significant differences in the preoperative measurements between the group and no significant differences between the clinical parameters at the final follow-up. The mean percentage slip was 17.1% preoperatively and 17.7% at the final follow-up (p = 0.35). Progressive instability was noted in 13 patients (8.2%) with DS and 6 patients (7.0%) with advanced DS, respectively (p = 0.81). There was radiological evidence of restabilization of the spine in 30 patients (35%) with preoperative instability. The success rate of microendoscopic laminotomy was good/excellent in 166 (69%), fair in 49 (20%) and poor in 27 patients (11%) in both groups.

Conclusion

Microendoscopic laminotomy is an effective form of surgical treatment for patients with DS and stenosis. Preservation of the stabilizing structures using this technique prevents postoperative instability. Cite this article: Bone Joint J 2018;100-B:499-506.

Efficacy of biolimus A9-eluting stent for treatment of right coronary ostial lesion with intravascular ultrasound guidance: a multi-center registry

The aim of this study was to assess the efficacy of a biolimus A9-eluting stent in patients with a right coronary artery (RCA) ostial lesion. Ostial lesions of the RCA have been a limitation of percutaneous coronary intervention even in the drug-eluting stent (DES) era. However, clinical outcomes after the deployment of a second generation DES to an RCA ostial lesion with intravascular ultrasound (IVUS) guidance have not been fully elucidated. From September 2011 to March 2013, 74 patients were enrolled in 17 centers from Japan. RCA ostial lesion was defined as de novo significant stenotic lesion located within 15 mm from ostium. IVUS was used for all cases to confirm the location of ostium and evaluate stent coverage of ostium. Patients with hemodialysis were excluded. The primary endpoint is a major adverse cardiac event (MACE) at 1 year. Forty two percent of patients had multi-vessel disease. Angiographically severe calcification was observed in 26% of the lesions. The mean stent diameter was 3.3 ± 0.3 mm (3.5 mm, 72%, 3.0 mm, 25%, and 2.75 and 2.5 mm, 3%), stent length was 17.5 ± 5.8 mm, and dilatation pressure of stenting was 15.6 ± 4.1 atm. RCA ostium was covered by stent in all lesions in IVUS findings. Post dilatation was performed for 64% of lesions (balloon size 3.7 ± 0.6 mm). MACE rate at 1 year was 5.4% (target lesion revascularization 5.4%, myocardial infarction 1.2%, and no cardiac death). The biolimus A9-eluting stent for RCA ostial lesions with IVUS guidance showed favorable results at 1-year follow-up.