Effectiveness of Vericiguat on right ventricle to pulmonary artery uncoupling associated with heart failure with reduced ejection fraction.

BACKGROUNDS: A soluble guanylyl cyclase stimulator vericiguat has been shown to reduce cardiovascular mortality or hospitalization for heart failure in patients with worsening heart failure in the VICTORIA study. However, little is known about the effects of vericiguat on biventricular structure and function. METHODS AND RESULTS: A retrospective analysis of 63 consecutive patients with heart failure with reduced ejection fraction (HFrEF) who were treated with vericiguat was performed. Clinical data and echocardiographic parameters were compared between baseline and follow-up after the initiation of vericiguat. The median follow-up duration was 266 days. Treatment with vericiguat significantly reduced the plasma BNP levels (log-transformed) compared to baseline (2.46 ± 0.51 vs. 2.14 ± 0.58, p < 0.0001). Left ventricular end-diastolic volume index and left ventricular end-systolic volume index were significantly reduced (LVEDVI, 113.5 ± 46.3 vs. 103.6 ± 51.0, p = 0.0056; LVESVI, 82.0 ± 41.9 vs. 72.8 ± 44.7, p = 0.0077; respectively). The tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP) ratio, an indicator of right ventricle-pulmonary artery (RV-PA) coupling, increased significantly after the treatment (0.56 ± 0.29 vs. 0.92 ± 1.09, p < 0.0001). Univariate and multivariate analyses showed that the treatment effects of vericiguat on BNP levels, LV reverse remodeling, and RV-PA coupling were not correlated with the achievement of the quadruple therapy with beta-blockers, renin-angiotensin system inhibitors, mineralocorticoid inhibitors, and sodium-glucose cotransporter-2 inhibitors, nor with worsening heart failure (WHF). CONCLUSION: Treatment with vericiguat improved adverse LV remodeling and RV-PA uncoupling in HFrEF patients. These effects were independent of WHF and achieving the quadruple therapy. Patients with HFrEF may benefit from early initiation of vericiguat to prevent biventricular adverse remodeling.

Hemoglobin Level Can Predict Heart Failure Hospitalization in Patients with Advanced Heart Failure Awaiting Heart Transplantation without Inotropes or Mechanical Circulatory Support.

Although anemia is a common comorbidity that often coexists with heart failure (HF), its clinical impact in patients with advanced HF remains unclear. We investigated the impact of hemoglobin levels on clinical outcomes in patients with advanced HF listed for heart transplantation without intravenous inotropes or mechanical circulatory support.We retrospectively reviewed the clinical data of patients listed for heart transplantation at our institute who did not receive intravenous inotropes or mechanical circulatory support between 2011 and 2022. We divided the patients into those with hemoglobin levels lower or higher than the median value and compared the composite of all-cause death and HF hospitalization within 1 year from the listing date.We enrolled consecutive 38 HF patients (27 males, 49.1 ± 10.8 years old). The median hemoglobin value at the time of listing for heart transplantation was 12.9 g/dL, and 66.7% of the patients had iron deficiency. None of the patients in either group died within 1 year. The HF hospitalization-free survival rate was significantly lower in the lower hemoglobin group (40.9% versus 81.9% at 1 year, P = 0.020). Multivariate Cox proportional hazards model analysis showed that hemoglobin as a continuous variable was an independent predictor for HF hospitalization (odds ratio 0.70, 95% confidence interval 0.49-0.97, P = 0.030).Hemoglobin level at the time of listing for heart transplantation was a predictor of hospitalization in heart-transplant candidates without intravenous inotropes or mechanical circulatory support.

Hypertrophic cardiomyopathy-related left ventricular pseudoaneurysm: A case report.

Background: Myocardial infarction-related left ventricular pseudoaneurysm (LVP), covered by the adjacent pericardial or scar tissue, is a fatal sequela of left ventricular rupture. Whereas hypertrophic cardiomyopathy (HCM) may cause left ventricular true aneurysm. Differentiating LVP from left ventricular true aneurysm is crucial because their natural histories and treatment strategies are distinct. However, the incidence and management of HCM-related LVP remain unknown. Case presentation: An 88-year-old man was admitted to our hospital with sudden-onset chest pain. Upon initial examination, vital signs were stable, and a grade 4/6 systolic murmur was noted. An electrocardiogram revealed atrial fibrillation and poor R-wave progression without ST-T changes or negative T-waves. An echocardiography showed mild left ventricular hypertrophy, mid-ventricular obstruction with a significant intraventricular pressure gradient, left ventricular outflow tract obstruction, and a small left ventricular apical outpouching. Cardiac computed tomography angiography (CCTA) assisted in the diagnosis of LVP, and an accompanying pericardial effusion suggested impending cardiac rupture. Because the patient initially refused our proposed urgent surgery, medication was initiated with continuous hemodynamic monitoring in the intensive care unit; however, the patient's condition did not improve. During a semi-urgent surgical repair of the aneurysmal wall, LVP was observed and confirmed by pathology. Myocardial tissue adjacent to the pseudoaneurysm was consistent with that of HCM. Subsequently, a final diagnosis of HCM-related LVP was made. The postoperative course was notable for transient profound hypotension. Thereafter, the patient died of non-occlusive mesenteric ischemia on day 6. Conclusions: To our knowledge, this is the first reported case of HCM-related LVP mimicking impending cardiac rupture. Our case highlights the importance of considering HCM-related LVP in patients with left ventricular outpouching and CCTA in the LVP diagnosis. In further research, data on the appropriate management of HCM-related LVP should be accumulated.

Use of endoscopic hand-suturing to treat refractory bleeding from a gastric ulcer in a patient with a left ventricular assist device.

We herein describe a 49-year-old man with severe heart failure due to fulminant myocarditis who underwent left ventricular assist device implantation and received clopidogrel and warfarin as antithrombotic agents. The patient developed anemia secondary to chronic bleeding gastric hyperplastic polyps, necessitating endoscopic mucosal resection. Despite attempts to manage post-endoscopic mucosal resection bleeding from a gastric ulcer by endoscopic hemostasis using hemostatic forceps, local hemostatic agents, and polyglycolic acid sheets, the bleeding persisted. Hemostasis of the refractory bleeding was finally achieved by endoscopic hand-suturing of the ulcer. One month later, the ulcer was almost completely scarred. This case has important clinical value in that it demonstrates the efficacy of endoscopic hand-suturing even in challenging cases such as refractory bleeding gastric ulcers in patients with left ventricular assist devices.

Overview of the 87th Annual Scientific Meeting of the Japanese Circulation Society (JCS2023)　- New Challenge With Next Generation.

The 87thAnnual Meeting of the Japanese Circulation Society (JCS2023) was held in March 2023 in Fukuoka, Japan, marking the first in-person gathering after the COVID-19 pandemic. With the theme of "New Challenge With Next Generation" the conference emphasized the development of future cardiovascular leaders and technologies such as artificial intelligence (AI). Notable sessions included the Mikamo Lecture on heart failure and the Mashimo Lecture on AI in medicine. Various hands-on sessions and participatory events were well received, promoting learning and networking. Post-event surveys showed high satisfaction among participants, with positive feedback on face-to-face interactions and the overall experience. JCS2023, attended by 17,852 participants, concluded successfully, marking a significant milestone in post-pandemic meetings, and advancing cardiovascular medicine.

Impact of patisiran on health status and quality of life in patients with transthyretin cardiac amyloidosis

INTRODUCTION APOLLO-B is a Phase 3 study of patisiran in patients with transthyretin (ATTR) cardiac amyloidosis (NCT03997383), which demonstrated a significant benefit in functional capacity (6-MWT), and health status and quality of life (QoL) (KCCQ-OS) with patisiran vs placebo at Month (M) 12. HYPOTHESIS Patisiran improves health status and QoL in the daily lives of patients with ATTR cardiac amyloidosis vs placebo. METHODS Patients were 18-85 years old with ATTR amyloidosis and a medical history of heart failure (HF) due to ATTR cardiomyopathy, with ≥1 prior hospitalization for HF or current clinical evidence of HF. Patients were randomized (1:1) to intravenous patisiran 0.3 mg/kg or placebo every 3 weeks. These post-hoc analyses evaluated percentage of responders reporting ≥5-point improvement in KCCQ-OS, and change from baseline in 4 KCCQ domains and questions within the domains. RESULTS 359 patients received study drug (patisiran, N=181; placebo, N=178): median age (range), 76 (41, 85) years; male, 89%; wild-type ATTR, 80%; 25% were on tafamidis at baseline. At M12, patisiran showed significant benefit vs placebo in KCCQ-OS (LS mean [SEM] change from baseline: patisiran, 0.30 [1.26]; placebo, -3.41 [1.28]; LS mean [SEM] difference: 3.71 [1.80]; p=0.0397). A ≥ 5-point improvement in KCCQ at M12 was more frequent with patisiran vs placebo (34.1 vs 24.0%: difference [95% CI] 10.1% [0.7, 19.5]). Improvement vs placebo was consistent across domains, with LS mean differences [95% CI] in change from baseline (patisiran - placebo) in Physical Limitations (2.75 [-1.24, 6.74]), Total Symptoms (4.55 [0.75, 8.34]), QoL (4.27 [-0.12, 8.65]), and Social Limitations (2.76 [-2.21, 7.73]). Categorical changes from baseline to M12 demonstrated greater percentages of placebo-treated patients reporting worsening for questions in each domain, including activities requiring greater cardiometabolic demand. In patients with values at baseline and M12, notably greater percentages (>5%) of placebo- vs patisiran-treated patients reported worsening (percent difference; n=placebo/patisiran) for questions related to Walking 1 Block on Level Ground (10%; n=159/162), Frequency and Burden of Dyspnea (9.5% and 7.6%; n=164/170), Frequency of Orthopnea (9.6%; n=163/170), Feeling about Spending the Rest of Their Life with HF the Way It Is Right Now (6.4%; n=164/170), and Intimate Relationships (6.3%; n=88/86). Improvement from baseline was reported by greater percentages (>5%) of patisiran-treated patients (percent difference; n=patisiran/placebo) in Enjoyment of Life Limited Due to HF (12.8%; n=170/164) and Hobbies/Recreational Activities (6.0%; n=141/143). CONCLUSIONS In APOLLO-B, improvements in health status and QoL with patisiran vs placebo were apparent across all 4 KCCQ domains. Greater percentages of patisiran-treated patients had KCCQ-OS improved by ≥ 5 points at M12 and they more often reported improvements in QoL, and ability to enjoy life and perform hobbies/recreational activities. More placebo-treated patients reported worsening in walking on level ground, HF symptoms and QoL.

Development of deep-learning models for real-time anaerobic threshold and peak VO2 prediction during cardiopulmonary exercise testing.

AIMS: Exercise intolerance is a clinical feature of patients with heart failure (HF). Cardiopulmonary exercise testing (CPET) is the first-line examination for assessing exercise capacity in patients with HF. However, the need for extensive experience in assessing anaerobic threshold (AT) and the potential risk associated with the excessive exercise load when measuring peak oxygen uptake (peak VO2) limit the utility of CPET. This study aimed to use deep-learning approaches to identify AT in real time during testing (defined as real-time AT) and to predict peak VO2 at real-time AT. METHODS AND RESULTS: This study included the time-series data of CPET recorded at the Department of Cardiovascular Medicine, Kyushu University Hospital. Two deep neural network models were developed to: (i) estimate the AT probability using breath-by-breath data and (ii) predict peak VO2 using the data at the real-time AT. The eligible CPET contained 1472 records of 1053 participants aged 18-90 years and 20% were used for model evaluation. The developed model identified real-time AT with 0.82 for correlation coefficient (Corr) and 1.20 mL/kg/min for mean absolute error (MAE), and the corresponding AT time with 0.86 for Corr and 0.66 min for MAE. The peak VO2 prediction model achieved 0.87 for Corr and 2.25 mL/kg/min for MAE. CONCLUSION: Deep-learning models for real-time CPET analysis can accurately identify AT and predict peak VO2. The developed models can be a competent assistant system to assess a patient's condition in real time, expanding CPET utility.

Cardiopulmonary exercise testing can be used to evaluate the condition of patients with heart failure during exercise. Developed deep-learning models can accurately predict a patient's anaerobic threshold in real time and peak oxygen uptake. The models can be used by clinicians for more objective and accurate assessments in real time, expanding the utility of cardiopulmonary exercise testing.

Genotyping of Mycoplasma pneumoniae strains isolated in Japan during 2019 and 2020: spread of p1 gene type 2c and 2j variant strains.

We characterized 118 Mycoplasma pneumoniae strains isolated from three areas of Japan (Saitama, Kanagawa, and Osaka) during the period of 2019 and 2020. Genotyping of the p1 gene in these strains revealed that 29 of them were type 1 lineage (29/118, 24.6%), while 89 were type 2 lineage (89/118, 75.4%), thereby indicating that type 2 lineage was dominant in this period. The most prevalent variant of type 2 lineage was type 2c (57/89, 64%), while the second-most was type 2j, a novel variant identified in this study (30/89, 33.7%). Type 2j p1 is similar to type 2 g p1, but cannot be distinguished from reference type 2 (classical type 2) using the standard polymerase chain reaction-restriction fragment length polymorphism analysis (PCR-RFLP) with HaeIII digestion. Thus, we used MboI digestion in the PCR-RFLP analysis and re-examined the data from previous genotyping studies as well. This revealed that most strains reported as classical type 2 after 2010 in our studies were actually type 2j. The revised genotyping data showed that the type 2c and 2j strains have been spreading in recent years and were the most prevalent variants in Japan during the time-period of 2019 and 2020. We also analyzed the macrolide-resistance (MR) mutations in the 118 strains. MR mutations in the 23S rRNA gene were detected in 29 of these strains (29/118, 24.6%). The MR rate of type 1 lineage (14/29, 48.3%) was still higher than that of type 2 lineage (15/89, 16.9%); however, the MR rate of type 1 lineage was lower than that found in previous reports published in the 2010s, while that of type 2 lineage strains was slightly higher. Thus, there is a need for continuous surveillance of the p1 genotype and MR rate of M. pneumoniae clinical strains, to better understand the epidemiology and variant evolution of this pathogen, although M. pneumoniae pneumonia cases have decreased significantly since the COVID-19 pandemic.

Propensity-Matched Study of Early Cardiac Rehabilitation in Patients With Acute Decompensated Heart Failure.

BACKGROUND: The impact of early implementation of cardiac rehabilitation (CR) in heart failure (HF) patients remains to be elucidated. This study sought to determine whether CR during HF hospitalization could improve prognostic outcomes in patients with acute decompensated HF. METHODS: We analyzed patients with HF enrolled in the JROADHF (Japanese Registry of Acute Decompensated Heart Failure) registry, a retrospective, multicenter, nationwide registry of patients hospitalized for acute decompensated HF. Eligible patients were divided into 2 groups according to CR during hospitalization. The primary outcome was a composite of cardiovascular death or rehospitalization due to cardiovascular event after discharge. The secondary outcomes were cardiovascular death and cardiovascular event rehospitalization. RESULTS: Out of 10 473 eligible patients, 3210 patients underwent CR. Propensity score matching yielded 2804 pairs. Mean age was 77±12 years and 3127 (55.8%) were male. During a mean follow-up of 2.8 years, the CR group had lower incidence rates of the composite outcome (291 versus 327 events per 1000 patient-years; rate ratio, 0.890 [95% CI, 0.830-0.954]; P=0.001) and rehospitalization due to cardiovascular event (262 versus 295 events per 1000 patient-years; rate ratio, 0.888 [95% CI, 0.825-0.956]; P=0.002) than the no CR group. In-hospital CR was associated with an improvement in Barthel index for activities of daily living (P=0.002). Patients with very low Barthel index at admission were benefited by CR in comparison with patients with independent Barthel index (very low; hazard ratio, 0.834 [95% CI, 0.742-0.938]: independent; hazard ratio, 0.985 [95% CI, 0.891-1.088]; P for interaction=0.035). CONCLUSIONS: CR implementation during hospitalization was associated with better long-term outcomes in patients with acute decompensated HF. These data support the need for a randomized, controlled, adequately powered trial to definitively test the role of early physical rehabilitation in hospitalized patients with HF.

Frequency and clinical features of radiographic head injury caused by inpatient falls: a single-centre retrospective cohort study.

OBJECTIVES: The lack of clear criteria makes it difficult for clinicians to determine which patients should be imaged after an inpatient fall. This study identified the clinical characteristics of patients who required a head CT scan following an inpatient fall. DESIGN: This was a retrospective cohort study conducted from January 2016 to December 2018. We obtained the data from our safety surveillance database, which record all cases of inpatient falls in our hospital. SETTING: Single-centre, tertiary, secondary care hospital. PARTICIPANTS: We included all consecutive patients who claimed to have fallen and bruised their heads as well as patients who were confirmed to have a bruise on the head but were unavailable to be interviewed about the fall. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was radiographic head injury revealed on head CT after a fall. RESULTS: Overall, 834 adult patients (662 confirmed and 172 suspected cases) were included. The median age was 76 years, and 62% were men. Patients with radiographic head injury were more likely to have a lower platelet count, consciousness disturbance and new vomiting episodes compared with those without radiographic head injury (all p<0.05). The use of anticoagulants or antiplatelets was not different between patients with and without radiographic head injury. Among the 15 (1.8%) patients with a radiographic head injury, 13 with intracranial haemorrhage had at least one of the following characteristics: received anticoagulant or antiplatelet agents, platelet count of <2.0×109/L, consciousness disturbance or new vomiting episodes. There were no deaths among patients with radiographic head injuries. CONCLUSIONS: The incidence of radiographic head injury due to falls in adult inpatients with suspected or confirmed head injuries was 1.8%. Only patients with risk factors had radiographic head injuries, which might help reduce the number of unnecessary CT scans in inpatient falls. TRIAL REGISTRATION NUMBER: Study protocol (Kurashiki Central Hospital, Medical ethical committee. IRB no. 3750).

Nationwide Temporal Trends in Clinical Characteristics and Treatment of Dilated Cardiomyopathy From 2003 to 2013 in Japan　- A Report From Clinical Personal Records.

BACKGROUND: Little is known about nationwide temporal trends in the clinical characteristics and treatment of dilated cardiomyopathy (DCM) in Japan.Methods and Results: We collected data regarding demographics, echocardiography, and treatment of DCM between 2003 to 2013 from Clinical Personal Records, a national registry organized by the Japanese Ministry of Health, Labour, and Welfare. Among the 40,794 DCM patients screened, 27,702 with left ventricular ejection fraction (LVEF) <50% and age ≥18 years were enrolled in this study and divided into 3 groups according to registration year: Group 1, 2003-2005 (10,006 patients); Group 2, 2006-2010 (11,252 patients); and Group 3, 2011-2013 (6,444 patients). Over time, there were decreases in age at registration (mean [±SD] 58.6±13.0 vs. 56.8±13.8 vs. 56.2±13.8 years; P<0.001) and LVEF (33.5±10.0% vs. 31.1±9.9% vs. 29.2± 9.7%; P<0.001), and an increase in patients with New York Heart Association Class III-IV (28.2% vs. 35.2% vs. 41.0%; P<0.001). The use of ß-blockers (59.1% vs. 79.3% vs. 87.8%; P<0.001) and mineralocorticoid receptor antagonists (30.6% vs. 35.8% vs. 39.7%; P<0.001) increased over time. In multivariate analysis, male sex, systolic blood pressure, chronic kidney disease, hemoglobin, and registration year were positively associated, whereas age and LVEF were negatively associated, with ß-blocker prescription. CONCLUSIONS: Although the clinical characteristics of DCM changed, the implementation of optimal medical therapy for DCM increased from 2003 to 2013 in Japan.

The gastric double-stripe sign of chronic mesenteric ischemia: A case report.

RATIONALE: Atherosclerotic chronic mesenteric ischemia (CMI) is caused by stenosis or occlusion of mesenteric arteries and can progress to potentially life-threatening acute mesenteric ischemia if left untreated. However, correct diagnosis and timely treatment remain a challenge due to a lack of awareness, variable symptoms, and inconclusive diagnostic testing. PATIENT CONCERNS: An 82-year-old man with multiple cardiovascular risk factors, including chronic kidney disease, presented with dyspnea, anorexia, and oliguria. Laboratory results revealed severe renal dysfunction (raised serum blood urea nitrogen of 83.8 mg/dL, serum creatinine levels of 8.20 mg/dL, and decreased estimated glomerular filtration rate of 5.5 mL/min/1.73 m 2 ), hypoalbuminemia, and moderate anemia. A provisional diagnosis of acute exacerbation of chronic kidney disease was made and the patient required tentative intermittent hemodialysis, received blood transfusions, and was eventually placed on maintenance hemodialysis. However, the patient's symptoms did not improve. Esophagogastroduodenoscopy (EGD) revealed longitudinal gastric ulcers on the anterior and posterior walls of the stomach, which were named "a gastric double-stripe sign" because the lesions corresponded to the watershed areas of the stomach. No Helicobacter pylori infection or malignancy was identified, and increasing the dose of lansoprazole had no beneficial effects. Doppler ultrasound revealed high peak systolic velocity (270 cm/s) of the celiac artery (CA), suggesting CA stenosis, which was confirmed by magnetic resonance angiography. DIAGNOSIS: Final diagnosis of CMI was made based on patient's symptoms, EGD findings, Doppler ultrasound, and magnetic resonance angiography. INTERVENTIONS: Endovascular revascularization for CA stenosis was performed. OUTCOMES: The patient obtained symptomatic relief concomitant with the resolution of the gastric ulcers. The post-procedural course of the patient was uneventful and he remained healthy at the 1-year follow-up. LESSONS: This is the first case of CMI with EGD finding of a gastric double-stripe sign specific for gastric ischemia. This case highlights the clinical importance of this endoscopic finding in patients with suspected atherosclerotic CMI.

Subacute hemorrhagic pericardial tamponade after COVID-19 infection mimicking carcinomatous pericarditis: a case report.

Background: Coronavirus disease (COVID-19)-associated acute pericarditis has recently received much attention owing to its high frequency associated with pericardial tamponade (PT), showing unfavorable prognosis. However, early diagnosis and treatment remain challenging in cases of non-specific signs and symptoms. Case presentation: A 64-year-old man was admitted to our hospital for acute osteomyelitis of the toes and was properly treated with antimicrobial agents. Three days after admission, the patient developed mild COVID-19 without pneumonia, for which early anti-COVID-19 agents were initiated. Nevertheless, the patient developed hemorrhagic PT due to acute pericarditis 2 weeks later, which was confirmed by cardiac magnetic resonance, requiring an urgent pericardiocentesis. Although cytological analysis of the hemorrhagic pericardial fluid strongly suggested adenocarcinoma, the atypical cells were eventually proven to be mesothelial cells with reactive atypia. Furthermore, lymph nodes swelling with abnormal 2-[18F]-fluoro-2-deoxy-D-glucose accumulation on imaging were suggestive of malignancy. However, biopsy examination revealed multiple non-caseating granulomas in the lymph node, unlikely due to malignancy. Eventually, the temporal association of the preceding COVID-19 with the occurrence of subacute PT without other identifiable cause led to a final diagnosis of COVID-19-associated acute pericarditis. With anti-inflammatory and corticosteroids treatment, the patient's symptoms involving the pericardial structure and function were completely resolved along with improvements in size of the affected lymphadenopathies. Conclusions: We encountered a unique case of COVID-19-associated acute pericarditis exhibiting hemorrhagic PT. This case underscores the residual risk of delayed pericardial involvement even in patients with mild COVID-19 who receive early treatment, and the recognition that COVID-19 may cause various cytomorphological and histological features. Additionally, the importance of considering this rare entity as a cause of hemorrhagic pericardial effusions should be highlighted.

Decisive diagnostic clue for infectious abdominal aortic aneurysm caused by Arthrobacter russicus in a diabetic elderly woman with renal dysfunction: A case report and literature review.

Infectious aortic aneurysm (IAA) can be a rare but potentially fatal sequela of infectious inflammatory disease of the aortic wall with a high incidence of rupture. The definitive diagnosis is based on vascular imaging of the aneurysm using contrast-enhanced computed tomography (CE-CT) and identification of the causative microorganism from positive blood cultures (BCs). However, IAA remains extremely difficult to diagnose and treat in patients with prior antimicrobial treatment or with renal dysfunction. Here we describe a case of an 85-year-old woman with IAA caused by Arthrobacter russicus presenting with abdominal pain and fever that was initially diagnosed as a presumptive urinary tract infection and treated with empiric antimicrobial therapy. However, persistent abdominal pain with increased serological inflammation necessitated further evaluation. Unenhanced multimodality imaging considering the renal dysfunction revealed infectious aortitis of the infrarenal abdominal aorta, together with the initial culture results, leading to the tentative diagnosis of Klebsiella pneumoniae aortitis. Thereafter, serial monitoring with unenhanced magnetic resonance angiography (MRA) using thin-slab maximum intensity projection (TS-MIP) revealed acute aortic expansion strongly suggestive of a pseudoaneurysm that was successfully treated with early surgical repair under adequate infection control. Despite negative Gram staining and tissue culture results for the excised aortic wall, a definitive diagnosis of IAA secondary to A. russicus rather than K. pneumoniae was finally made by confirming the histologic findings consistent with IAA and the identification of A. russicus 16S rRNA on the resected aortic wall. The patient also developed a vascular graft infection during the postoperative course that required long-term systemic antimicrobial therapy. This case highlights the value of unenhanced MRA in the early detection of IAA in patients with renal dysfunction and the importance of a molecular diagnosis for identifying the causative microorganism in cases of culture- or tissue-negative IAA.