Forleo, Cinzia

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 >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.

Background Transthyretin amyloid cardiomyopathy (ATTR‐CM) has a specific pathophysiology, with myocardial stiffening and systolic dysfunction only in advanced stages. We aimed to investigate the response to cardiac resynchronization therapy (CRT) in ATTR‐CM compared with heart failure. Methods In this multicenter, observational study, patients with ATTR‐CM receiving CRT (n=101) were matched to patients without amyloid cardiomyopathy by sex, age, and implantation type (CRT with versus without defibrillator versus conduction system pacing, upgrade versus first implant). We evaluated changes in QRS duration and echocardiographic parameters following CRT implantation and at the most recent available assessments. The study end points were all‐cause death alone or combined with heart failure hospitalization. Results Patients with ATTR‐CM (median age, 76 [interquartile range, 72–83] years, 98% men, left ventricular (LV) ejection fraction 30% [26–33]) showed greater QRS shortening after CRT implantation ( P =0.012), but not after a median of around 1 year ( P =0.152). There were no significant differences in the absolute LV ejection fraction changes immediately after implantation (+7 [+2/+10] versus +3 [0/+9] units; P =0.124), or to the last echo ( P =0.796), which was performed after 1.3 years in patients with ATTR‐CM and 2.9 years in patients without amyloid cardiomyopathy. Patients with ATTR‐CM had a shorter survival than controls ( P <0.001 for both end points). Patients with ATTR‐CM experiencing an early improvement in LV ejection fraction had a longer survival (log‐rank, 4.3; P =0.038). Conclusions Following CRT implantation, patients with ATTR‐CM show QRS narrowing and improvement in LV ejection fraction, not different from patients without amyloid cardiomyopathy. Early favorable LV remodeling seems to be associated with a lower risk of all‐cause death.