Yield of bone scintigraphy screening for transthyretin-related cardiac amyloidosis in different conditions: Methodological issues and clinical implications.

BACKGROUND: Transthyretin-related cardiac amyloidosis (TTR-CA) is thought to be particularly common in specific at-risk conditions, including aortic stenosis (AS), heart failure with preserved ejection fraction (HFpEF), carpal tunnel syndrome (CTS) and left ventricular hypertrophy or hypertrophic cardiomyopathy (LVH/HCM). METHODS: We performed a systematic revision of the literature, including only prospective studies performing TTR-CA screening with bone scintigraphy in the above-mentioned conditions. Assessment of other forms of CA was also evaluated. For selected items, pooled estimates of proportions or means were obtained using a meta-analytic approach. RESULTS: Nine studies (3 AS, 2 HFpEF, 2 CTS and 2 LVH/HCM) accounting for 1375 screened patients were included. One hundred fifty-six (11.3%) TTR-CA patients were identified (11.4% in AS, 14.8% in HFpEF, 2.6% in CTS and 12.9% in LVH/HCM). Exclusion of other forms of CA and use of genetic testing was overall puzzled. Age at TTR-CA recognition was significantly older than that of the overall screened population in AS (86 vs. 83 years, p = .04), LVH/HCM (75 vs. 63, p < .01) and CTS (82 vs. 71), but not in HFpEF (83 vs. 79, p = .35). In terms of comorbidities, hypertension, diabetes and atrial fibrillation were highly prevalent in TTR-CA-diagnosed patients, as well as in those with an implanted pacemaker. CONCLUSIONS: Screening with bone scintigraphy found an 11-15% TTR-CA prevalence in patients with AS, HFpEF and LVH/HCM. AS and HFpEF patients were typically older than 80 years at TTR-CA diagnosis and frequently accompanied by comorbidities. Several studies showed limitations in the application of recommended TTR-CA diagnostic algorithm, which should be addressed in future prospective studies.

Diagnostic pathways to wild-type transthyretin amyloid cardiomyopathy: a multicentre network study.

AIM: Epidemiology of wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) remains poorly defined. A better characterization of pathways leading to ATTRwt-CA diagnosis is of key importance, and potentially informative of disease course and prognosis. The aim of this study was to describe the characteristics of contemporary pathways leading to ATTRwt-CA diagnosis, and their potential association with survival. METHODS AND RESULTS: This was a retrospective study of patients diagnosed with ATTRwt-CA at 17 Italian referral centres for CA. Patients were categorized into different 'pathways' according to the medical reason that triggered the diagnosis of ATTRwt-CA (hypertrophic cardiomyopathy [HCM] pathway, heart failure [HF] pathway, incidental imaging or incidental clinical pathway). Prognosis was investigated with all-cause mortality as endpoint. Overall, 1281 ATTRwt-CA patients were included in the study. The diagnostic pathway leading to ATTRwt-CA diagnosis was HCM in 7% of patients, HF in 51%, incidental imaging in 23%, incidental clinical in 19%. Patients in the HF pathway, as compared to the others, were older and had a greater prevalence of New York Heart Association (NYHA) class III-IV and chronic kidney disease. Survival was significantly worse in the HF versus other pathways, but similar among the three others. In multivariate model, older age at diagnosis, NYHA class III-IV and some comorbidities but not the HF pathway were independently associated with worse survival. CONCLUSIONS: Half of contemporary ATTRwt-CA diagnoses occur in a HF setting. These patients had worse clinical profile and outcome than those diagnosed either due to suspected HCM or incidentally, although prognosis remained primarily related to age, NYHA functional class and comorbidities rather than the diagnostic pathway itself.

Incidence and risk factors for pacemaker implantation in light-chain and transthyretin cardiac amyloidosis.

AIMS: The incidence and risk factors of pacemaker (PM) implantation in patients with cardiac amyloidosis (CA) are largely unexplored. We sought to characterize the trends in the incidence of permanent PM and to identify baseline predictors of future PM implantation in light-chain (AL) and transthyretin (ATTR) CA. METHODS AND RESULTS: Consecutive patients with AL and ATTR-CA diagnosed at participating centres (2017-2020) were included. Clinical data recorded within ±1 month from diagnosis were collected from electronic medical records. The primary study outcome was the need for clinically-indicated PM implantation. Patients with PM (n = 41) and/or permanent defibrillator in situ (n = 13) at CA diagnosis were excluded. The study population consisted of 405 patients: 29.4% AL, 14.6% variant ATTR and 56% wild-type ATTR; 82.5% were male, median age 76 years. During a median follow-up of 33 months (interquartile range 21-46), 36 (8.9%) patients experienced the primary outcome: 10 AL-CA, 2 variant ATTR-CA and 24 wild-type ATTR-CA (p = 0.08 at time-to-event analysis). At multivariable analysis, history of atrial fibrillation (hazard ratio [HR] 3.80, p = 0.002), PR interval (HR 1.013, p = 0.002) and QRS >120 ms (HR 4.7, p = 0.001) on baseline electrocardiogram were independently associated with PM implantation. The absence of these three factors had a negative predictive value of 92% with an area under the curve of 91.8% at 6 months. CONCLUSION: In a large cohort of AL and ATTR-CA patients, 8.9% received a PM within 3 years after diagnosis. History of atrial fibrillation, PR >200 ms and QRS >120 ms predicted future PM implantation.

Low QRS Voltages in Cardiac Amyloidosis: Clinical Correlates and Prognostic Value.

Background: Low QRS voltages (LQRSVs) are a common electrocardiographic feature in patients with light chain amyloidosis (AL) and transthyretin amyloidosis (ATTR) cardiac amyloidosis (CA). Objectives: The aim of this study was to identify clinical and echocardiographic correlates of LQRSV and to investigate their prognostic significance in patients with CA. Methods: This was a multicenter, retrospective study performed in 6 CA referral centers including consecutive patients with AL and ATTR CA. LQRSVs were defined as a QRS amplitude ≤5 mm (0.5 mV) in all peripheral leads. The study outcome was cardiovascular (CV) mortality. Results: Overall, 411 (AL CA: n = 120, ATTR CA: n = 291) patients were included. LQRSVs were present in 66 (55%) patients with AL CA and 103 (35%) with ATTR CA (P < 0.001). In AL CA, LQRSVs were independently associated with younger age (P = 0.015), higher New York Heart Association functional class (P = 0.016), and natriuretic peptides (P = 0.041); in ATTR CA, LQRSVs were independently associated with pericardial effusion (P = 0.008) and lower tricuspid annulus peak systolic excursion (P = 0.038). During a median follow-up of 33 months (Q1-Q3: 21-46), LQRSVs independently predicted CV death in both AL CA (HR: 1.76; 95% CI: 2.41-10.18; P = 0.031) and ATTR CA (HR: 2.64; 95% CI: 1.82-20.17; P = 0.005). Together with the National Amyloidosis Centre (NAC) staging, LQRSVs provided incremental prognostic value in ATTR CA (AUC for NAC model: 0.83 [95% CI: 0.77-0.89]; AUC for NAC + LQRSV model: 0.87 [95% CI: 0.81-0.93]; P = 0.040). Conclusions: LQRSVs are common but not ubiquitous in CA; they are more frequent in AL CA than in ATTR CA. LQRSVs reflect an advanced disease stage and independently predict CV death. In ATTR CA, LQRSVs can provide incremental prognostic accuracy over the NAC staging system in patients with intermediate risk.