Naoyuki Otani

Introduction: Matrix stones are rare urinary calculi composed predominantly of organic matrix, with poorly understood pathogenesis. We herein report a case involving refractory matrix stones with longitudinal compositional changes and characterize the final specimen using histopathological and proteomic analyses. Case Presentation: A 54‐year‐old woman with long‐standing nephrolithiasis developed bilateral ureteral obstruction and recurrent pyelonephritis, requiring multiple transurethral ureterolithotripsy procedures, ureteral stenting, and percutaneous nephrostomy. Stone composition changed sequentially from predominantly calcium oxalate to struvite to proteinaceous (consistent with matrix stones). Histopathology revealed predominantly acellular eosinophilic material, minimal mucopolysaccharide deposition, phosphotungstic acid hematoxylin‐positive material suggestive of fibrin, and myeloperoxidase‐positive material within the matrix. Repeated liquid chromatography–tandem mass spectrometry reproducibly identified multiple neutrophil‐associated proteins. Conclusion: This report documents longitudinal changes preceding matrix stone development, suggesting an association between changes in stone composition and a sustained inflammatory and infectious milieu.

Renal hypouricemia (RHUC) is an inherited renal tubular disorder characterized by low serum uric acid levels and excessive urinary uric acid excretion due to impaired urate reabsorption in proximal tubules. Type 1 RHUC (RHUC1) is caused by pathogenic variants in URAT1/SLC22A12 . In Japanese patients, recurrent variants such as W258X and R90H account for a substantial proportion of RHUC1 cases; however, the clinical significance of rare URAT1 variant combinations remains incompletely understood. A 69-year-old woman was referred to our hospital for evaluation of renal dysfunction and hypouricemia. Laboratory examination revealed severe hypouricemia (serum uric acid, 0.7 mg/dL) and markedly increased urinary uric acid excretion (Cua/Ccr, 60.5%). She had chronic kidney disease (CKD) stage G3b and a renal stone. Genetic analysis identified two heterozygous variants, A209V and F379L, in URAT1/SLC22A12 gene. The variants were considered likely to represent compound heterozygosity based on the clinical phenotype and their previously reported functional impairment. Although A209V and F379L have individually been reported to impair urate transport, the clinical phenotype associated with this variant combination has not been well characterized. The severe hypouricemia and excessive urinary uric acid excretion observed in this patient provide clinical evidence supporting the pathogenic significance of the A209V and F379L combination. The coexistence of nephrolithiasis and CKD further raises the possibility that excessive urinary urate excretion and stone formation may contribute to renal dysfunction. In addition, the improvement in stone-related urinary abnormalities during potassium citrate treatment suggests that urinary alkalization may be beneficial in the management of nephrolithiasis associated with RHUC.

Hyperuricemia (HUA) is common among patients with chronic kidney disease (CKD) and has long been implicated in CKD development and progression [1,2]. Large cohort studies and meta-analyses have con...

Energy loss (EL) derived from vector flow mapping (VFM) is an indicator of intraventricular flow efficiency in the left ventricle. However, standardized re

Background: Dysuricemia, encompassing both hyperuricemia (serum uric acid: SUA > 7 mg/dl) and hypouricemia (SUA ≤ 3 mg/dL), has been linked to cardio-renal risks, but it remains unclear whether consistent or transient dysuricemia contributes to the risk of chronic kidney disease (CKD). Purpose: To investigate whether consistent and transient dysuricemia influences annual changes in the estimated glomerular filtration rate (eGFR) in healthy participants. Methods: We retrospectively analyzed 1142 healthy participants who underwent health checkups with at least four consecutive annual measurements of eGFR and SUA. Participants with consistently hyperuricemia, hypouricemia, or normouricemia (7 mg/dL ≥ SUA > 3 mg/dL) throughout follow-up were categorized as consistent hyperuricemia ( n = 36), consistent hypouricemia ( n = 8) and normouricemia ( n = 759), respectively. Others were classified as transient hyperuricemia ( n = 282) and transient hypouricemia ( n = 57). Annualized eGFR decline was compared using ANOVA, and incident CKD stage 3 events were evaluated using χ² or Fisher’s exact tests. Multivariable analyses were performed to examine the association between baseline SUA and subsequent renal outcomes. Results: Hyperuricemia was positively associated with obesity, liver dysfunction, dyslipidemia, and higher baseline eGFR compared with normouricemia, whereas hypouricemia showed negative associations with obesity and liver dysfunction. Transient hyperuricemia was significantly associated with obesity, liver dysfunction, and dyslipidemia relative to consistent normouricemia, while transient hypouricemia was negatively associated with obesity and liver dysfunction. Transient hyperuricemia exhibited significantly faster annual eGFR decline than normouricemia, while transient hypouricemia showed no significant difference. Baseline SUA ≥ 7 mg/dL was associated with higher baseline eGFR but predicted a significantly faster subsequent eGFR decline. In multivariable linear regression, baseline SUA level was independently associated with eGFR change, whereas baseline SUA status did not independently predict incident CKD stage 3. Conclusion: Transient hyperuricemia, rather than transient hypouricemia, is associated with accelerated eGFR decline in healthy individuals. Baseline SUA provides prognostic information regarding renal function trajectory, but does not independently predict CKD stage 3, suggesting that SUA should be interpreted as a clinically useful marker of renal vulnerability rather than a proven causal factor.

Hemodynamic force (HDF) analysis using vector flow mapping (VFM) enables noninvasive assessment of intraventricular pressure differences (IVPDs). In this study, we evaluated the apical suction from late systole to early diastole in patients with ischemic heart disease (IHD) with or without left ventricular aneurysm (LVA), validated against simultaneous left atrial–LV pressure measurements. A total of 37 participants were evaluated: 11 healthy controls, 11 patients with IHD without LVA, and 15 with LVA. VFM-derived IVPDs were quantified as IVPD recoil (late systole) or IVPD RF (early diastole). Patients with LVA showed markedly reduced IVPD recoil and the combined parameter (IVPD _VFM recoil + RF) compared with those with IHD, indicating impaired apical suction. IVPD RF and the combined parameter (IVPD _VFM recoil + RF) correlated with transmitral E-wave ( r = 0.54, P < 0.01 and r = 0.45, P = 0.03); the combined parameter (IVPD _VFM recoil + RF) showed significant correlation with catheter-derived simultaneous pressure differences ( r = 0.40, P < 0.05). These findings demonstrate that VFM identifies loss of apical suction in LVA and reflects impaired LA–LV driving force. VFM offers a practical noninvasive tool for evaluating diastolic suction beyond Doppler indices and may improve physiological assessment in post-infarction LV remodeling.

Background: Unilateral absence of the pulmonary artery (UAPA), a rare congenital condition, is associated with pulmonary hypertension in 25% of cases. Case Summary: A 67-year-old Japanese woman presented with UAPA and progressive severe pulmonary arterial hypertension. During hospitalisation for acute coronary syndrome 8 years ago, the patient experienced apnoea. A polysomnography test confirmed obstructive sleep apnoea syndrome. Home oxygen therapy (1 L/min) and continuous night-time positive pressure breathing therapy were initiated. Dyspnoea on exertion gradually worsened 1 year ago. The estimated right ventricular systolic pressure (RVSP) on echocardiography was elevated (73 mmHg). She was urgently admitted with progressive dyspnoea (World Health Organization [WHO] class II to class IV) and marked hypoxaemia, even when receiving oxygen (3 L/min). Isolated left UAPA with severe pulmonary hypertension was diagnosed based on right heart catheterisation. The patient declined continuous subcutaneous prostacyclin analogue injection. Therefore, triple therapy with macitentan (10 mg), selexipag (0.4 mg), and riociguat (3 mg) was initiated. However, RVSP remained high during the first 3 months. The selexipag dose was titrated to 3.2 mg/day over 6 months, which improved RVSP to 32 mmHg on echocardiography and the mean pulmonary artery pressure (PAP) on right heart catheterisation decreased to 39 mmHg. One year later, due to recurrent dyspnoea on light exertion, iloprost inhalation therapy was initiated. The patient has since progressed well, maintaining WHO class II during a 7-year follow-up period. Discussion: Prostacyclin inhalation combined with triple therapy can be an effective treatment strategy for patients with UAPA-associated pulmonary arterial hypertension.

Cancer-related venous thromboembolism (VTE) is a significant concern owing to its frequent occurrence and status as a leading cause of death in patients with cancer. Cancer-related VTE carries a higher risk of hemorrhage than VTE in patients without carcinoma. A 74-year-old woman with pancreatic head cancer presented with complaints of loss of appetite and weight loss. Contrast-enhanced computed tomography (CT) was performed for stage classification of pancreatic cancer, which incidentally revealed pulmonary thromboembolism. The patient remained clinically asymptomatic, with no evidence of hypoxemia or echocardiographic findings suggestive of pulmonary hypertension. Due to the unavailability of low-molecular-weight heparin for the treatment of acute pulmonary embolism and concerns about potential hemorrhage according to CT findings, unfractionated heparin was selected for its ability to be closely monitored and promptly discontinued if necessary. However, the treatment was immediately halted as the patient developed hematemesis and hemorrhagic shock. Subsequent CT confirmed gastrointestinal hemorrhage, and three-dimensional CT angiography identified the pancreaticoduodenal arcade as the source of bleeding. Emergency catheter angiography and transcatheter arterial embolization were performed, successfully achieving hemostasis. This case highlights the high risk of both recurrent VTE and bleeding complications in patients with cancer-related VTE, underscoring the need for individualized treatment strategies.

Brugada syndrome is a genetic arrhythmia characterized by coved ST-segment elevation in the right precordial leads, predisposing individuals to sudden cardiac death due to fatal ventricular arrhythmias. Currently, a type 1 Brugada electrocardiographic (ECG) pattern can be used to diagnose the condition; however, diagnosis is difficult because normal intercostal spaces do not always allow for the detection of a type 1 Brugada ECG. Sodium channel blockers, including pilsicainide, a class Ic antiarrhythmic agent, cause Brugada-type ECG patterns. We report the case of a 79-year-old man with no prior syncope or family history of Brugada syndrome who developed a drug-induced type 1 Brugada ECG pattern after treatment for paroxysmal atrial fibrillation with pilsicainide. The patient presented with palpitations and atrial fibrillation, for which pilsicainide and rivaroxaban were administered. ECG performed after symptom resolution revealed a coved-type ST-segment elevation characteristic of type 1 Brugada ECG. The patient remained asymptomatic, and pilsicainide was immediately discontinued. Subsequent ECGs normalized within 3 days. No ventricular arrhythmias were observed during >6 months of follow-up, and an implantable cardiac monitor was placed for ongoing surveillance.