The utility of zebrafish cardiac arrhythmia model to predict the pathogenicity of KCNQ1 variants.

Genetic testing for inherited arrhythmias and discriminating pathogenic or benign variants from variants of unknown significance (VUS) is essential for gene-based medicine. KCNQ1 is a causative gene of type 1 long QT syndrome (LQTS), and approximately 30% of the variants found in type 1 LQTS are classified as VUS. We studied the role of zebrafish cardiac arrhythmia model in determining the clinical significance of KCNQ1 variants. We generated homozygous kcnq1 deletion zebrafish (kcnq1del/del) using the CRISPR/Cas9 and expressed human Kv7.1/MinK channels in kcnq1del/del embryos. We dissected the hearts from the thorax at 48 h post-fertilization and measured the transmembrane potential of the ventricle in the zebrafish heart. Action potential duration was calculated as the time interval between peak maximum upstroke velocity and 90% repolarization (APD90). The APD90 of kcnq1del/del embryos was 280 ± 47 ms, which was significantly shortened by injecting KCNQ1 wild-type (WT) cRNA and KCNE1 cRNA (168 ± 26 ms, P < 0.01 vs. kcnq1del/del). A study of two pathogenic variants (S277L and T587M) and one VUS (R451Q) associated with clinically definite LQTS showed that the APD90 of kcnq1del/del embryos with these mutant Kv7.1/MinK channels was significantly longer than that of Kv7.1 WT/MinK channels. Given the functional results of the zebrafish model, R451Q could be reevaluated physiologically from VUS to likely pathogenic. In conclusion, functional analysis using in vivo zebrafish cardiac arrhythmia model can be useful for determining the pathogenicity of loss-of-function variants in patients with LQTS.

CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) update 2022.

Primary Percutaneous Coronary Intervention (PCI) has significantly contributed to reducing the mortality of patients with ST-segment elevation myocardial infarction (STEMI) even in cardiogenic shock and is now the standard of care in most of Japanese institutions. The Task Force on Primary PCI of the Japanese Association of Cardiovascular Interventional and Therapeutics (CVIT) society proposed an expert consensus document for the management of acute myocardial infarction (AMI) focusing on procedural aspects of primary PCI in 2018. Updated guidelines for the management of AMI were published by the European Society of Cardiology (ESC) in 2017 and 2020. Major changes in the guidelines for STEMI patients included: (1) radial access and drug-eluting stents (DES) over bare-metal stents (BMS) were recommended as a Class I indication, (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. In 2020, updated guidelines for Non-ST-Elevation Myocardial Infarction (NSTEMI) patients, the followings were changed: (1) an early invasive strategy within 24 h is recommended in patients with NSTEMI as a Class I indication, (2) complete revascularization in NSTEMI patients without cardiogenic shock is considered as Class IIa recommendation, and (3) in patients with atrial fibrillation following a short period of triple antithrombotic therapy, dual antithrombotic therapy (e.g., DOAC and single oral antiplatelet agent preferably clopidogrel) is recommended, with discontinuation of the antiplatelet agent after 6 to 12 months. Furthermore, an aspirin-free strategy after PCI has been investigated in several trials those have started to show the safety and efficacy. The Task Force on Primary PCI of the CVIT group has now proposed the updated expert consensus document for the management of AMI focusing on procedural aspects of primary PCI in 2022 version.

Impact of renal function on mid-term outcomes in heart failure patients treated with tolvaptan.

BACKGROUND:: Although tolvaptan, an electrolyte-free water diuretic for congestive heart failure (HF), is reported to have no effect on long-term mortality or HF-related morbidity, there may exist some subgroups of patients who may receive beneficial effect of tolvaptan. The purpose of this study was to identify clinical factors associated with mid-term effect of tolvaptan on clinical outcomes of patients who discharged after acute HF. METHODS:: We retrospectively analyzed 140 patients (88 male; mean age, 77.1 ± 11.0 years) with acute HF who received tolvaptan (initial dose 8.6 ± 3.6 mg/day) during their hospitalization. They were divided into two groups according to how the tolvaptan was used at discharge; 77 in the tolvaptan-continued group and 63 in the discontinued group. RESULTS:: The Cox proportional hazards model revealed that eGFR was the only independent predictor for the occurrence of mid-term cardiac events (composite of re-hospitalization due to HF and all-cause death; aHR = 0.9870, p = 0.02597). The Kaplan-Meier survival curves of the two groups demonstrated no difference in cumulative event-free rates. In the subgroup with preserved renal function at admission (eGFR ⩾ 30 ml/min/1.73 m2), the continuous use of tolvaptan increased composite events (aHR = 2.130, p = 0.02549). CONCLUSIONS:: The continuous use of tolvaptan after discharge did not affect mid-term cardiac events of HF overall but may be associated with increased cardiac events in the subgroup with preserved renal function. These findings suggest that the tolvaptan administration might need to be limited to treatment of in-hospital acute HF.

Impact of combined lipid lowering and blood pressure control on coronary plaque: myocardial ischemia treated by percutaneous coronary intervention and plaque regression by lipid lowering and blood pressure controlling assessed by intravascular ultrasonography (MILLION) study.

The aim of the study was to elucidate the aggressive reduction of both low-density lipoprotein cholesterol (LDL-C) and blood pressure (BP) reduced coronary atherosclerotic plaque volume compared with a standard treatment of LDL-C and BP in Japanese patients with coronary artery disease (CAD). This study is a prospective, randomized, and open-labelled with a blind-endpoint evaluation study. A total of 97 patients (81 men, mean age 62.0 ± 9.6) with CAD undergoing intravascular ultrasonography (IVUS)-guided percutaneous coronary intervention (PCI) were randomized, and 68 patients had IVUS examinations at baseline and at 18-24 months follow-up. Patients were randomly assigned to standard or aggressive strategies targeting LDL-C and a BP of 100 mg/dL and 140/90 mmHg vs. 70 mg/dL and 120/70 mmHg, respectively. The primary endpoint was the percent change in coronary plaque volume. Both standard and aggressive strategies succeeded to achieve target levels of LDL-C and BP; 74.9 ± 14.7 vs. 63.7 ± 11.9 mg/dL (NS) and 124.1 ± 9.4/75.8 ± 7.7 vs. 113.6 ± 9.6/65.8 ± 9.4 mmHg (systolic BP; NS, diastolic BP; p < 0.05), respectively. Both groups showed a significant reduction in the coronary plaque volume of -9.4 ± 10.7% and -8.7 ± 8.6% (NS) in standard and aggressive therapies, respectively. Both standard and aggressive intervention significantly regressed coronary plaque volume by the same degree, suggesting the importance of simultaneous reductions of LDL-C and BP for prevention of CAD.

Impact of combined lipid lowering with blood pressure control on coronary plaque regression: rationale and design of MILLION study.

A line of epidemiological studies suggests that the accumulation of coronary risk factors promotes the progression of coronary atherosclerosis. Recent clinical studies showed that aggressive low-density lipoprotein (LDL) cholesterol-lowering therapy using statins could regress coronary atheroma and reduce major cardiovascular events. Additionally, therapy that controlled amlodipine-based blood pressure reduced major cardiovascular events in patients with hypertension compared with an atenolol-based regimen. An open-label randomized multicenter study is primarily planned to evaluate the changes in coronary atheroma volume using intravascular ultrasonography 18-24 months after intensive lowering of LDL-cholesterol and blood pressure compared with a standard therapy indicated by current guidelines in Japanese patients with coronary artery disease (CAD). The secondary endpoints include changes in serum lipid levels, inflammatory markers, glucose markers and blood pressure. In total, 100 subjects with CAD who are undergoing percutaneous coronary intervention will be tested. The MILLION study will provide new evidence and therapeutic standards for the prevention of CAD in Japanese patients by controlling both LDL-C levels and blood pressure.

Impact of lesion morphology and associated procedures for left main coronary stenting on angiographic outcome after intervention: sub-analysis of Heart Research Group of Kanazawa, HERZ, Study.

Whether the lesion morphology and associated interventional procedures for the left main coronary artery disease (LMCA) could affect clinical outcome is still controversial. Therefore, we examined the impact of lesion morphology and associated procedures on clinical and angiographic outcomes of stenting for the LMCA. Among 7,660 patients with coronary intervention registered, we analyzed early angiographic results of 228 patients (179 men, mean age 69.4 years) concerned with LMCA lesions. In 121 out of 228 patients having long-term angiographic results, we examined the occurrence of major adverse coronary events (MACE) particularly in terms of the presence of acute coronary syndrome (ACS), the kind of stents, bear metal or drug eluting, the lesion morphology and associated procedures. Early angiographic success rate of LMCA stenting was 100 %, and clinical success rate was 94.3 %. During follow-up period for 3 years, MACE was observed in 17 patients. Under these conditions, multiple stenting (p < 0.01) and complicated procedures such as such as Y-stent, T-stent and crush stent (p < 0.01) were listed as risks for MACE, although there was no statistical difference in kinds of stent. Multivariate analysis demonstrated the significant disadvantage of complicated procedures using the bear metal stent on the occurrence of MACE (p < 0.01). These results demonstrate that the complicated procedures have great impact on clinical and angiographic outcomes after stenting for LMCA lesions, and suggest the simple procedure with a single stent for LMCA lesions in the present cohort. Whether the presence of ACS can affect the prognosis should further be sought.

Sinus dysfunction after stent implantation in the right coronary artery immediately recovered after reflow in the sinus node artery.

A 67-year-old man who had a history of syncope was admitted because of effort angina. The sinus node (SN) was the single blood supply from the right coronary artery (RCA). After we implanted 2 everolimus-eluting stents for RCA, slow-flow occurred and the SN artery was occluded, and junctional escape rhythm was sustained. After the wiring to the occluded SN artery, junctional escape rhythm immediately recovered to sinus rhythm, and the patient achieved continuous sinus rhythm and stable hemodynamics. Given that acute SN ischemia is a possible cause of sinus dysfunction, careful choice of a percutaneous coronary intervention strategy should be taken into consideration if the SN artery is the single blood supply from the RCA and if syncopal history is present.

A patient with significant slow-flow phenomenon during percutaneous coronary intervention for ST elevation myocardial infarction associated with scattered necrotic core by virtual histology intravascular ultrasound.

A 68-year-old man with acute ST elevation myocardial infarction (STEMI) underwent emergent coronary angiography which showed total occlusion in the proximal right coronary artery (RCA). Gray-scale intravascular ultrasound (IVUS) revealed the culprit lesion was expansively remodeled and contained ruptured and echolucent plaques with spotty calcification, whereas thin-capped fibroatheroma and a large amount of scattered necrotic core were observed by virtual histology (VH)-IVUS. After stent implantation in the proximal RCA under a filter protection, filter-no-reflow phenomenon occurred and thrombus-like defect was observed in the mid RCA. Under these conditions, VH-IVUS detected a large amount of scattered necrotic core in the mid RCA. We suggest scattered necrotic core detected by VH-IVUS may be associated with slow-flow phenomenon during percutaneous coronary intervention in our patient with STEMI.