The potential role of the aortic valve calcium score by computed tomography scan in the diagnosis of concomitant cardiac amyloidosis in patients with severe aortic stenosis

Abstract

Abstract Background Cardiac amyloidosis (CA) and aortic stenosis (AS) are two related, but the diagnosis of both these condition is challenging because of the common phenotype. Different predictors of CA in AS have been proposed in the last years. Purpose To identify a new red-flag of concomitant CA in patients with severe AS analyzing aortic valve calcium burden using calcium score, calcium mass and calcium volume by computed tomography scan (CT). Methods 55 patients with severe AS and suspicion of concomitant CA were retrospectively enrolled from 2009 to 2022. 5 Patients with a bicuspid aortic valve, previous aortic valve replacement, or an incomplete diagnostic workup for CA were excluded. 50 patients underwent CT-scan and were included in the final analysis. Results Of the 50 patients, 21 patients (AS-CA) had positive 99m Tc-DPD bone scintigraphy (19 with score 2 and 2 with score 3), none of the patients presented laboratory suspicion for AL amyloidosis, so all the patients had a diagnosis of transthyetin related CA. 29 patients (AS alone) had negative bone scintigraphy. AVA indexed were comparable between AS-CA and AS alone groups (0.3 mm2/m2, in both the group p: 0.88). Stroke volume, maximum and mean gradient were significatively lower in AS-CA group (29 vs 36 ml/m2, p: 0.01, 60 vs 72 mmHg, p: 0.016 and 34 vs 45 mmHg, p:0.01) with a higher percentage of low flow-low gradient aortic stenosis in AS-CA group (11 patients,52% vs 5 patients in AS-alone 17%, p: 0.014)ECG in AS-CA group showed atrial fibrillation in 12 patients (57%), versus 3 patients in the AS-alone group (10%), and lower QRS voltages (peripheral QRS score 44 mV vs 58 mV, p-value:0.017; total QRS score 120 mV versus 160 mV, p-value: 0.005). The echocardiogram showed a more thickened IVS and PW in AS-CA patients (17 versus 15 mm, p: 0.03 and 15 versus 14 mm, p: 0.01) with a decreases longitudinal systolic function (septal S wave at TDI 4.4 vs 5.1 cm/s, p: 0.011, lateral S wave 4.5 versus 5.6 cm/s, p: 0.014).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 (3569 vs 4480 Agatston units, p: 0.017) calcium volume (2575 vs 3445 mm3, p: 0.012) and calcium mass (798 vs 1082 g, p: 0.016).At logistic regression analyses,confirmed perdictors of concomitant CA in AS were: AS low flow- low gradient (p:0.011), atrial fibrillation (p:0.001), lower QRS score periferical(p:0.004) and total (p:0.002) and a decreased longitudinal systolic function (p:0.028). Regarding the aortic valve calcium burden, calcium score( p:0.031) and calcium volume(p:0.026) were confirmed predictor of CA in AS. Conclusions This study shows that calcium burden at CT scan in patients with concomitant CA-AS is significatily lower than in patients with AS alone. Calcium burden at CT scan could be used in addition to the classical parameters as a potential red-flag of concomitant CA in AS severe.