Tersalvi, Gregorio

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 In patients with suspected amyloid cardiomyopathy (CM) and a monoclonal protein, tissue biopsy is mandatory to exclude amyloid light-chain CM (AL-CM), the subtype requiring urgent therapy. We aimed to develop a pragmatic approach to estimate the most likely final diagnosis before biopsy. Methods We studied a multicenter cohort of adults referred for biopsy because of suspected amyloid CM. Clinical, laboratory, ECG/echocardiographic and bone-tracer scintigraphy data were collected at initial suspicion. In patients with a monoclonal protein, we derived age cut-offs overall and by carpal tunnel syndrome (CTS), defined an age-based "gray zone" (74–83 years), and evaluated risk modifiers for AL-CM and transthyretin CM (ATTR-CM). We built a points-based algorithm for "gray-zone" patients. Clinical utility was assessed using decision-curve analysis. Results Among 602 patients (median age 76 years; 81% male), 524 (87%) had a monoclonal protein. In the monoclonal-protein subgroup, ATTR-CM accounted for 49%, AL-CM for 30%, and neither ATTR- nor AL-CM for 21%. Age ≤73 years was the Youden-optimal threshold favoring AL-CM (sensitivity 66%, specificity 78%), whereas age &gt;84 years made AL-CM unlikely (sensitivity 98%, negative predictive value 94%), defining a "gray zone" (n=261; ATTR-CM 63%, AL-CM 18%, no amyloid CM 20%). Within the gray zone, abnormal free light-chain ratio, positive urine immunofixation, proteinuria, and higher troponin T and N-terminal pro-B-type natriuretic peptide (NT-proBNP) favored AL-CM, while higher Perugini grade, male sex, greater interventricular septal thickness, and higher NT-proBNP favored ATTR-CM. Penalized models achieved cross-validated area under the curves of 0.87 (AL-CM) and 0.94 (ATTR-CM). A two-score algorithm identified small gray-zone subsets enriched for AL-CM (positive predictive value 81.5%, specificity 98%) or ATTR-CM (positive predictive value 95.2%, specificity 94%). DCA showed higher net benefit for score- and model-based strategies versus treat-all/treat-none across clinically relevant threshold probabilities, with consistent patterns across regions. Conclusions In patients with suspected amyloid CM and a monoclonal protein, age- and CTS-anchored stratification refined by a compact set of routine laboratory and imaging features provides actionable pre-biopsy probabilities and may help prioritize urgent biopsy and AL-directed work-up while definitive tissue typing is pursued.For image description, please refer to the figure legend and surrounding text.

Abstract Isolated cardiac sarcoidosis (iCS), defined by granulomatous inflammation limited to the myocardium, represents the most diagnostically challenging and prognostically adverse form of sarcoidosis. As it is fundamentally a diagnosis of exclusion, iCS diagnosis relies on the absence of extracardiac sarcoid and the integration of multimodality imaging, endomyocardial biopsy, and molecular testing, each with inherent limitations. Cardiac magnetic resonance and positron emission tomography provide complementary assessment of inflammation, fibrosis, and ventricular function, enhancing diagnostic confidence. Electroanatomic mapping-guided biopsy may improve histologic yield, whereas genetic testing helps exclude phenocopies such as arrhythmogenic, hypertrophic, or dilated cardiomyopathies. Circulating biomarkers remain non-specific but may complement imaging-based algorithms. Future research should focus on harmonized imaging protocols, non-FDG radiotracers, and molecular tissue profiling to refine activity assessment and guide therapy. Multimodal, probability-based frameworks represent the most promising approach for earlier, more accurate diagnosis and risk stratification in iCS.

The results underscore a multifaceted interaction among cardiopulmonary hemodynamics, right heart pressures, ventilatory response, and autonomic regulation. In particular, altered RV-PA coupling correlated with heightened sympathetic drive, indicating that cardiopulmonary efficiency and hemodynamics may influence central autonomic outputs. This suggests that mechanical stress or overload in the right heart could modulate sympathovagal balance, thereby contributing to altered autonomic responses during exercise in patients with cardiopulmonary disorders.

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

BACKGROUND: Guidelines recommend 3-hour cardiac amyloid radionuclide imaging (CARI) for transthyretin amyloid cardiomyopathy. Citing rapid blood clearance of 99m Tc-hydroxymethylene-diphosphonate (HMDP) and efficient laboratory throughput, 1-hour imaging is increasingly practiced despite limited supporting evidence. We sought to compare diagnostic performance and interpreter experience of 1-hour versus 3-hour HMDP-CARI. METHODS: Consecutive patients with suspected transthyretin amyloid cardiomyopathy (n=114) underwent both 1-hour and 3-hour HMDP single photon emission computed tomography (CT)/CT. Two cardiologist-radiologist reader teams, blinded to imaging timepoint (1 versus 3 hours), assessed overall interpretation, single photon emission CT–based Perugini grade, interpretation difficulty, interpreter confidence, and need for CT-fused images for anatomic localization. Discordant, equivocal, and difficult cases were arbitrated by a third tie-breaking team. The myocardial-to-blood-pool radiotracer uptake ratio (3-dimensional Score) was measured as a surrogate of contrast resolution. RESULTS: Interinterpreter agreement was high at both time points (κ≥0.81), with more cases requiring arbitration at 3 hours versus 1 hour (22% versus 13%; P =0.049). Overall interpretation and Perugini grades were concordant between time points in 111/114 (97%) and 106/114 (93%) patients, respectively. Three patients (3%) were negative at 1 hour but equivocal at 3 hours, all of which were clinically ruled out for transthyretin amyloid cardiomyopathy. Interpreter confidence was comparable at both timepoints (97% versus 95%; P =0.317). Compared with 3-hour imaging, contrast resolution was inferior (lower 3-dimensional score, P <0.001) and CT fusion was more frequently needed (57% versus 31%, P <0.001) at 1-hour imaging. CONCLUSIONS: In a prospective, blinded comparison of 1-hour versus 3-hour HMDP-CARI, diagnostic performance and interpreter experience were similar, with readers requesting CT fusion more frequently at 1 hour to optimize myocardial-to-blood pool discrimination.

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