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.

Diagnostic pathways leading to arrhythmogenic left ventricular cardiomyopathy in a single center cohort

Background

Despite major advances, the recognition of arrhythmogenic left ventricular cardiomyopathy (ALVC) remains challenging, since this clinical entity is often concealed in different clinical settings both in terms of clinical onset and imaging phenotype, resulting in significant delays in diagnosis with prognostic implications.

Purpose

To describe a single Center cohort of ALVC patients, focusing on the spectrum of clinical presentation and diagnostic pathways.

Methods

Patients were retrospectively evaluated between January 2012 and January 2022. Diagnosis was based on 1) ≥3 contiguous segments with subepicardial/midwall LGE in the LV at cardiac magnetic resonance (CMR) plus a likely pathogenic/pathogenic arrhythmogenic cardiomyopathy (ACM) associated genetic mutation and/or familial history of ACM and/or red flags for ALVC (i.e, negative T waves in V4–6/aVL, low voltages in limb leads) or 2) pathology examination of explanted hearts/autoptic cases suffering from sudden cardiac death (SCD). Patients with significant right ventricular involvement were excluded.

Results

Sixty-six patients were evaluated for suspected ALVC: 8 phenocopies were excluded (6 acute myocarditis and 2 sarcoidosis) after a comprehensive clinical and multi-modality instrumental evaluation. The final study cohort was composed by 56 patients (55% males, median age 45 years), from 36 families. Diagnostic pathways leading to diagnosis were: SCD in 4 (7%), ventricular arrhythmias in 11 (20%), chest pain in 9 (16%), heart failure in 7 (12%), and familial screening in 25 (45%) (Figure 1). An echocardiogram was available for all but 2 patients with SCD: 25 (46%) had normal phenotype, 17 (32%) had a hypokinetic non dilated cardiomyopathy, and 12 (22%) had a dilated cardiomyopathy (DCM). Of the 49 tested patients, 31 (63%) had a pathogenic/likely pathogenic DNA variant: desmoplakin (DSP, N=21), filamin C (FLNC, N=4), SCN5A (N=3) were the most frequently involved genes; 8 patients had a double gene mutation. Twenty-four patients (43%) had previously received a diagnosis other than ALVC: 10 idiopathic DCM, 9 acute myocarditis, 4 post-myocarditis DCM, 2 acute myocardial injury/non-ST elevated myocardial infarction. In 13 patients ALVC was diagnosed with the introduction of CMR in the diagnostic work-up of a DCM, in 2 cases the diagnosis was done with the pathology examination after heart transplantation. The median diagnostic delay was of 8 years, with a maximum of 20 years. It is worth nothing that patients from the same family might have different diagnostic pathways and phenotypes of ALVC (Figure 2).

Conclusions

ALVC is a challenging diagnosis, hidden in different clinical scenarios. Five main clinical pathways leading to ALVC diagnosis may be identified: ventricular arrhythmias, chest pain, heart failure, SCD at first presentation, and clinical/instrumental familial screening.

Funding Acknowledgement

Type of funding sources: None.

Different aortic valve calcium scores by computed tomography scan in patients with severe aortic stenosis and concomitant cardiac amyloidosis

Background

The coexistence of cardiac amyloidosis (CA) and degenerative aortic stenosis (AS) is increasing but the diagnosis is challenging because these two conditions share a common echocardiographic phenotype (1). Different predictors have been proposed in the last few years, including clinical, ECG-graphic and echocardiographic features (2–3).

Purpose

To identify a new marker of concomitant CA in patients with severe AS analyzing computed tomography scan (CT).

Methods

55 patients with severe AS and suspicion of concomitant CA were retrospectively enrolled. Patients with a bicuspid aortic valve, previous aortic valve replacement, or an incomplete diagnostic workup for CA were excluded. 33 patients underwent CT-scan and were included in the final analysis.

Results

None of the patients presented laboratory suspicion for AL amyloidosis; 12 patients (AS-CA) had positive 99m Tc-DPD bone scintigraphy (two with visual score 1, eight score 2 and two score 3), 21 patients (AS-alone) had negative bone scintigraphy. AS-CA patients had a median age of 85,5 years (versus 81,5) with only one female patient (versus 8 in the AS-alone group). AVA indexed were comparable between AS-CA and AS-alone groups (0,4 versus 0, 3 mm2/m2, p: 0.25). Stroke volume evaluated by pulsed Doppler, maximum and mean gradient were significatively lower in AS-CA group (respectively 30 versus 41 ml/m2, p: 0.017, 62 versus 74 mmHg, 0.038 and 33 versus 46 mmHg, p:0.022) with a higher percentage of low flow-low gradient aortic stenosis in AS-CA group (7 patients, 58% vs 3 patients in AS-alone 14%, p: 0.027), in line with the literature. ECG at first presentation in AS-CA group showed atrial fibrillation in 8 patients (67%), versus 2 patients in the AS-alone group (10%), and lower QRS voltages (peripheral QRS score 40 mV vs 51 mV, p-value:0.017; total QRS score 113 mV versus 155 mV, p-value: 0.005). The echocardiogram showed a more thickened IVS and PW in AS-CA patients (17 versus 15 mm, p: 0.05 and 15 versus 14 mm, p: 0.013), an augmented left ventricular mass (441 versus 356 g, p: 0.036) with a decreases longitudinal systolic function (septal S wave at TDI 4.4 versus 5.2 cm/s, p: 0.026, lateral S wave 4.1 versus 5.6 cm/s, p: 0.024) and a reduction in myocardial contraction fraction (12 versus 14%, p: 0.036).

CT- aortic valve calcium was quantified by an experienced operator. A statistically significant difference between AS-CA and AS-alone groups was observed in calcium score (3345 versus 4785 Hounsfield units, p: 0.037) calcium volume (2411 versus 3626 mm2, p: 0.03) and calcium mass (687 versus 1147 g, p: 0.023)

Conclusions

This study is the first to our knowledge to use relative aortic valve calcium score evaluation from CT imaging to characterize patients with severe AS with or without concomitant CA in addition to the classical clinical, ECG graphic, echocardiographic parameters. CT-aortic valve calcium burner was significatively lower in patients with concomitant CA.

Funding Acknowledgement

Type of funding sources: None. CT scan and bone scintigraphy

Analysis of characteristics and prognostic impact of phenotypes in hereditary ATTR

Background

Hereditary transthyretin-related amyloidosis (h-ATTR) is a systemic infiltrative disease caused by a single amino acid mutation on the transthyretin (TTR) gene, which destabilizes the protein and can determine its deposition on multiple organs, including heart and peripheral nervous system.

Purpose

We aimed to characterize and compare clinical, instrumental, and prognostic features of patients affected by h-ATTR by dividing the population into the disease's main phenotypes (unaffected carriers, cardiac, neurological or mixed phenotype).

Methods

Two hundred and eighty-five subjects of a single-centre cohort with a recognized pathogenic mutation on TTR gene were retrospectively included in the analysis. Phenotypes of disease were defined at baseline. Neurological phenotype (NP) was defined according to sensorimotor and/or autonomic dysfunction, while cardiac phenotype (CP) was defined in the presence of unexplained maximum wall thickness >12 mm and other typical echocardiographic findings. Unaffected carriers (UC) and mixed phenotypes (MP) presented none or both of the above-mentioned features, respectively.

Results

Two hundred and ten patients showed clinical signs of the disease, 37 (13%) with CP, 65 (23%) with NP and 108 (38%) with MP, while 75 subjects (26%) were UC. Ile68Leu was the most represented mutation (96 subjects, 34%), followed by Val30Met (21%) and Glu89Gln (13%). NP patients (mostly Val30Met) had mPND score >1 in 45% of patients, were younger at diagnosis (mean 47 years, p<0,001 vs CP/MP), and sex was equally distributed. In contrast, CP patients were older at diagnosis (mean 70 years, p<0,001 vs CP/MP), predominantly male (as well as in MP) with a higher incidence of tunnel carpal syndrome and a shorter time interval between onset of symptoms and diagnosis (mean 17 months, p<0,001 vs CP/MP). NYHA class, ECG findings, left ventricular wall thickness and ejection fraction did not significantly differ between CP and MP. After a mean follow-up of 59 months, 98 (34%) patients died. On a Kaplan-Meier survival analysis, mean survival times were 208, 123, 150 and 95 months for UC, CP, NP and MP, respectively, with a statistically significant difference in affected patients between NP and MP (p=0.012).

Conclusions

H-ATTR is a rare systemic disorder whose natural history, including age of onset, clinical characteristics and instrumental findings, is strongly influenced by primary phenotypes, ranging from the excellent prognosis of unaffected carriers to the inauspicious outcome of mixed phenotypes.

Funding Acknowledgement

Type of funding sources: None.