Bois, Melanie C.

Abstract Background Cardiac papillary fibroelastoma (PFE) is the most common benign primary cardiac tumor. Despite their benign pathology, PFEs pose a significant embolic risk, which can lead to severe neurological sequelae. However, subclinical or silent emboli often go undetected, presenting a diagnostic challenge. This study aims to assess the prevalence of silent emboli in patients with pathology-proven PFEs using brain magnetic resonance imaging (MRI). Methods We conducted a retrospective review of 385 cases of pathology-confirmed PFEs. Inclusion criteria was those with brain MRI performed within 5 years of surgical resection of the PFE and no clinical neurological events. Patients with a history of symptomatic cerebral infarction (stroke or TIA) were excluded. Patient demographics and PFE imaging features were analyzed by two cardiologists experienced in cardiac tumors. Clinical neurological data, and MRI findings were analyzed by two neurologists with expertise in cerebrovascular disease. Results Out of 385 patients, 132 underwent brain MRI. In the entire cohort, 105/385 patients (27%) experienced clinically overt embolic events. After excluding patients with symptomatic cerebral infarctions and MRI scans older than 5 years, 27 patients (mean age: 71±9.6, gender: 66% female) met the inclusion criteria. Of these, 8 patients (30%) showed signs of silent infarctions on MRI, with 4 (15%) displaying findings consistent with cerebral infarction highly suggestive for embolic source. Conclusion This study underscores the substantial risk of silent cerebral embolic events in patients with PFE. The limited availability of MRI data, largely attributable to the absence of standardized neuroimaging protocols, indicates that the true prevalence of silent embolization in this population is likely underestimated. Given the propensity of PFE to generate clinically silent emboli, systematic cerebral MRI should be strongly considered as part of the diagnostic assessment of patients with cardiac masses, irrespective of neurological symptoms. Early identification of subclinical cerebrovascular lesions may facilitate timely therapeutic decision-making and secondary prevention strategies, thereby reducing the risk of future symptomatic and potentially disabling ischemic strokes.

BACKGROUND: Technetium-based cardiac amyloid radionuclide imaging enables noninvasive diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM), but conventional planar and visual semiquantitative approaches have important limitations. We developed the quantitative 3-dimensional Mayo 3D Score, defined as the ratio of mean left ventricular myocardial radiotracer uptake to right atrial blood-pool uptake using computed tomography (CT)-fused single-photon emission CT (SPECT) volumes of interest, and sought to validate its diagnostic performance against myocardial pathology. METHODS: Consecutive patients who underwent 99m Tc-pyrophosphate SPECT/CT at Mayo Clinic for suspected ATTR-CM between June 2017 and January 2025 with archived myocardial tissue were included. Baseline characteristics, including demographics, echocardiogram, biomarkers, visual semiquantitative, and Mayo 3D Score metrics, were collected. Myocardial specimens underwent histopathologic confirmation of amyloid, with amyloid subtype determination and further semiquantitative grading of amyloid burden and deposition patterns. RESULTS: Among 230 patients (median age, 72 years; 78% male), 107 (47%) had ATTR-CM, of whom 9 had hereditary ATTR-CM. The Mayo 3D Score showed excellent discrimination against pathology (area under the receiver operating characteristic curve, 0.92 [0.88–0.96]), exceeding planar Perugini (0.87 [0.83–0.92]; P =0.006), and heart-to-contralateral lung ratio (0.86 [0.81–0.91]; P =0.004) and comparable to SPECT Perugini (0.90 [0.86–0.94]; P =0.12). A cutoff ≥1.0 yielded 86.0% sensitivity, 92.7% specificity, 91.1% positive predictive value, and 88.4% negative predictive value. Among ATTR-positive cases, the Mayo 3D Score correlated strongly with semiquantitative amyloid burden (Spearman ρ=0.69), was higher in pericellular than nodular deposition patterns ( P <0.001), and was not associated with vascular involvement ( P =0.42). CONCLUSIONS: In patients with suspected ATTR-CM undergoing 99m Tc-pyrophosphate SPECT/CT, the Mayo 3D Score demonstrated superior diagnostic performance compared with planar metrics and comparable to SPECT Perugini, while correlating with myocardial ATTR burden and deposition patterns on pathology. These findings support its integration as a quantitative adjunct within clinical diagnostic ATTR-CM workflows.

Abstract Background Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment and are increasingly associated with cardiovascular toxicities, including myocarditis and accelerated atherosclerosis. While ICI myocarditis has received substantial attention, thrombotic complications remain underrecognized and may be difficult to distinguish from immune-mediated cardiac inflammation and cancer-related hypercoagulable state. We present a case of non-bacterial thrombotic endocarditis (NBTE) and myocardial microthrombi mimicking ICI myocarditis. Case summary A 76-year-old woman with metastatic adenosquamous lung carcinoma presented with progressive dyspnoea 3 weeks after initiating pembrolizumab. Pulmonary arterial and coronary imaging were unremarkable, but cardiac magnetic resonance imaging (MRI) showed late gadolinium enhancement (LGE) and myocardial oedema suggestive of ICI myocarditis. Chest computed tomography revealed inflammatory lung changes, and empirical corticosteroids were initiated with initial clinical improvement. One week later, brain MRI showed multifocal infarcts, and Doppler ultrasound identified bilateral lower extremity deep vein thromboses. Transoesophageal echocardiography showed thickened mitral and aortic valves with moderate regurgitation. Non-bacterial thrombotic endocarditis with embolic phenomena was suspected. Anticoagulation was escalated from apixaban to therapeutic enoxaparin, followed by warfarin. Despite initial stabilization, the patient died 2 months later. Post-mortem examination revealed fibrin-rich valvular vegetations consistent with NBTE, widespread intramyocardial thrombi, and no histopathologic evidence of myocarditis. Discussion This case underscores how microthrombotic complications of ICI therapy may closely mimic myocarditis on imaging. Nonspecific cardiac MRI findings, such as LGE and T2 signal elevation, can result from thrombotic or ischaemic injury alike. Histopathologic confirmation may be required for accurate diagnosis, as misclassification can lead to suboptimal treatment.

Abstract Background Cardiac masses encompass a broad differential, including benign tumours, malignancies, and pseudotumours. Accurate diagnosis requires integration of clinical context, patient characteristics, lesion location, and imaging features. In select cases, tissue characterization is necessary. We describe a case of a rapidly enlarging interatrial mass following transcatheter aortic valve implantation (TAVI). Case summary A 70-year-old man underwent TAVI for severe low-flow, low-gradient aortic stenosis. Preprocedural imaging revealed an incidental interatrial mass consistent with lipomatous hypertrophy of the atrial septum (LHAS). Six months later, the mass showed significant interval growth, raising concern for malignancy. Multimodality imaging, including cardiac magnetic resonance imaging and FDG positron emission tomography yielded indeterminate results. An echocardiography-guided biopsy was performed, and histopathologic analysis confirmed LHAS with intralesional haemorrhage likely incurred during the TAVI procedure. Discussion While LHAS is typically benign and stable or slowly progressive, rare cases may present with atypical features and rapid growth, mimicking malignant cardiac tumours. This case represents the first reported instance of LHAS with haemorrhagic expansion.

Abstract Background 99mTc-labelled cardiac scintigraphy enables noninvasive diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM). Guidelines recommend using planar semiquantitative (heart to contralateral ratio, H/CL) and single photon emission computed tomography (SPECT) qualitative visual grading for diagnostic interpretation. However, planar imaging has inherent limitations, and visual grading is prone to interobserver variability, underscoring the need for standardized quantitative assessment. We developed a 3D volumetric quantitative score (3D Score) and assessed its diagnostic performance compared to myocardial tissue, the gold standard for ATTR-CM diagnosis. Methods At a single, tertiary referral center, we retrospectively identified consecutive patients from 06/2017 to 06/2024 who underwent 3-hour 99mTc-pyrophosphate or 99mTc-hydroxymethylene diphosphonate planar and SPECT/CT for suspected ATTR-CM and had archived myocardial tissue (biopsy or myectomy). On planar imaging, H/CL was calculated. On SPECT/CT, volumes of interest were drawn around the entire left ventricle (LV), avoiding calcifications, and within the right atrium (RA) blood pool. Mean uptake values were used to calculate the 3D Score (LVmean:RAmean), Fig 1A. Myocardial tissue was stained via sulfated Alcian blue and/or Congo red histochemistry. Once histologically confirmed, amyloid deposits were subtyped by liquid chromatography tandem mass spectrometry. The diagnostic performance of H/CL and 3D Score was assessed using receiver operating characteristic (ROC) curve analysis and predictive characteristics were defined. ROC areas under the curve (AUC) were compared using Delong test. Optimal cutoffs were determined using Youden’s J statistic. Baseline characteristics (demographics, echocardiogram, biomarkers) and H/CL were compared between patients above and below 3D Score cutoff. Results 239 patients were identified (median age 72 [65-78], 78% male, 46% ATTR positive). Median time between cardiac scintigraphy and myocardial tissue collection was 22 (6-65) days. Distribution of the 3D Score stratified by ATTR-CM status is illustrated in Fig 1B-C. The discriminative ability of the 3D Score was excellent (AUC 0.92) and superior to H/CL (0.87, p =0.006, Fig 1D-E). The optimal 3D Score cutoff for identifying ATTR-CM was ≥1.0 with sensitivity of 86%, specificity of 92%, positive predictive value (PPV) 90%, and negative predictive value (NPV) 89%. The optimal H/CL ratio cutoff for identifying ATTR-CM was ≥1.4 with sensitivity of 72%, specificity of 86%, PPV 81%, NPV 78%. Baseline characteristics of the overall cohort stratified by 3D Score are displayed in Table 1. Conclusions The 3D Score demonstrated excellent diagnostic performance for detecting ATTR-CM and was superior to current quantitative metrics. Future studies are needed to externally validate its performance across diverse patient cohorts and imaging centers and to investigate correlation with myocardial amyloid burden. Figure 1

Abstract Background In patients with heart failure with preserved ejection fraction (HFpEF), studies have described different HFpEF phenogroups based on medical comorbidities and variable echocardiographic, invasive hemodynamic, and biomarker data. We hypothesized that myocardial histopathologic findings may define phenogroups with differing clinical features and outcomes in patients with HFpEF. Methods We analyzed consecutive patients with left HF and EF ≥50% who underwent right ventricular septal endomyocardial biopsy (EMB) at our institution between 2001 and 2022 to investigate HF etiology. Patients with infiltrative or hypertrophic cardiomyopathy, sarcoidosis, myocarditis, primary valvular heart disease, constrictive pericarditis, isolated right HF, or insufficient EMB samples were excluded. Clinical, echocardiographic, and invasive hemodynamic data were collected. The severity of hypertrophy and fibrosis on EMB specimens was characterized (semiquantitative grading) by experienced cardiac pathologists based on standard histologic stains. Patients were stratified into four phenogroups based on EMB findings: "mild" (none/mild hypertrophy and fibrosis), "hypertrophy" (moderate/marked hypertrophy, minimal/mild fibrosis), "fibrosis" (moderate/marked fibrosis, none/mild hypertrophy), and "severe" (moderate/marked hypertrophy and fibrosis). Results Among the 121 patients analyzed, the median age was 67 years, 50% were female and cardiovascular conditions were common (Table 1). Fibrosis was graded as minimal in 21% (n=25), mild in 64% (n=77), moderate in 12% (n=15), and marked in 3% (n=4). Hypertrophy was graded as none in 4% (n=5), mild in 41% (n=50), moderate in 40% (n=48), and marked in 15% (n=18). Only one patient had the isolated "fibrosis" phenogroup and was excluded from further analysis, while 54 had the "mild", 48 had the "hypertrophy", and 18 had the "severe" phenogroup (Table 1). The "hypertrophy" phenogroup exhibited significantly higher rates of hypertension, diabetes, RV dilation, and higher pulmonary artery pressures. Over a median follow-up of 7.9 years (3.1–13.8), mortality rate varied according to the histopathologic phenogroups (Figure 1, p=0.034) with "severe" having the worst and "mild" having the best outcomes. Survival analyses based on fibrosis grades alone, hypertrophy grades alone, or echocardiographic hypertrophy did not reveal significant differences (all p = NS). Differences in survival remained significant adjusting for age (HR 3.39, 95% CI 1.20-9.58). Conclusions The integrated severity of histopathologic hypertrophic and fibrotic remodeling defined HFpEF phenogroups with variable prognosis. Clinical features did not reliably identify histopathologic phenogroups. These data suggest that advanced myocardial phenotyping (e.g., gene, protein, metabolism) may reveal unique HFpEF myocardial subtypes in need of specific therapies.Figure 1

Case Description: Immune checkpoint inhibitors (ICIs) have transformed cancer therapy but are associated with immune-related adverse events, including cardiovascular toxicity. While ICI-myocarditis is rare but potentially fatal, thrombotic complications—such as venous thromboembolism, arterial occlusion, and non-bacterial thrombotic endocarditis (NBTE)—are underrecognized. These raise questions about the roles of malignancy-associated hypercoagulability versus ICI-induced effects. We present a case of NBTE and myocardial microthrombi mimicking ICI-myocarditis. A 76-year-old woman with metastatic adenosquamous lung cancer and recent DVT (on apixaban and aspirin) presented with worsening dyspnea three weeks after starting pembrolizumab (Image 1). One week earlier, CT pulmonary angiography and coronary angiography were unrevealing. On presentation, she was stable but had peripheral edema, a late diastolic murmur, and elevated hs troponin (706→657→656 ng/L). NT-proBNP was 11,500 pg/mL. Cardiac MRI showed mid-wall late gadolinium enhancement (LGE), myocardial edema, and elevated T2 values—findings concerning for ICI-myocarditis. She initially improved on intravenous methylprednisolone. A week later, brain MRI showed multifocal embolic infarcts. Doppler ultrasound revealed a new left-sided DVT. TEE showed no intracardiac thrombus but identified a thickened aortic valve with moderate-to-severe regurgitation, a thickened mitral A2 segment with moderate regurgitation, and a patent foramen ovale (PFO) with left-to-right shunting. Findings raised concern for NBTE with systemic embolism or paradoxical embolism. Anticoagulation was transitioned to heparin, then warfarin. She was discharged on oral prednisone without further cancer therapy. Two months later, she died suddenly. Autopsy revealed fibrin-rich vegetations on the mitral valve consistent with NBTE and thromboembolic infarcts in small myocardial arteries, without inflammatory infiltrates or myocardial scarring (Image 2 and 3). Conclusion: This case highlights NBTE and microthrombi as important mimics of ICI-myocarditis. Despite MRI features suggestive of inflammation, pathology confirmed ischemic injury. ICIs have been suggested to promote thrombosis through elevated factor VIII, von Willebrand factor, reduced protein S, and systemic inflammation. Clinicians should consider thrombotic mimics in ICI-treated patients with cardiac symptoms and abnormal imaging. Tissue diagnosis may be necessary to guide management.

Context.— A clinic was created for patients to review their explanted organs with a pathologist. Objective.— To prospectively investigate the benefits of this type of clinic as perceived by both transplant patients and their pathologists. Design.— In this prospective study, patients participated in a videotaped viewing of heart and/or lung explants by the patient and their guest(s) and pathologist (December 2017–August 2022). Patients received a 3D-printed replica of their explant. After viewing the explanted organ, patients and their guests participated in an interview to assess their experiences. Video-reflexive ethnography was used by pathologists for data collection and practice improvement. Results.— Of 143 patients who viewed their explanted organ, 21 patients consented to having the organ-viewing session taped and to participate in a postviewing interview. The study group was comprised of 12 men; the median age was 57.5 years (range, 29–67 years). Five pathologists took part in reflexive sessions. The clinics were viewed positively by patients, providing an opportunity to better understand their disease. Pathologists had a similarly positive experience and gained important insights to patient journeys. Proposals for improvement were brought forward from both patients and pathologists. Conclusions.— Video-reflexive ethnography provided the opportunity for patients and pathologists to reflect on patient-pathology clinic appointments. This work serves as a template to build out pathology-based clinics.

Abstract Background There remains a lack of consensus regarding the postoperative treatment regimen in patients with native valve Staphylococcus aureus infective endocarditis who undergo surgical valve replacement or repair. Methods We conducted a multicenter retrospective review of patients with S aureus native valve endocarditis who underwent surgical valve replacement or repair at Mayo Clinic Enterprise (Minnesota, Florida, Arizona, and Mayo Clinic Health Systems) between 1 January 2012 and 31 December 2022. Postoperative treatment regimens were classified as either monotherapy with a methicillin-sensitive or methicillin-resistant S aureus active agent or combination therapy that included rifampin and/or gentamicin with either active agent. Results Of the 339 patients diagnosed with S aureus native valve endocarditis, 61 underwent surgical valve replacement or repair within the initial 6 weeks of antimicrobial therapy. A total of 12 (20.2%) patients died during the 1-year follow-up period. Between patients postoperatively treated with monotherapy (n = 33) and combination therapy (n = 28), a propensity score–weighted analysis revealed that combination therapy was associated with increased risk of 1-year mortality (P = .039), 6-month relapse (P = .016), and treatment-related adverse events (P &lt; .001). Conclusions Among patients treated for native valve infective endocarditis caused by S aureus after valvular surgical intervention, all study outcomes—adverse events and drug-drug interactions, 6-month infective endocarditis relapse, and 1-year mortality—were higher in the combination therapy group than the monotherapy group.