Diagnostic score for the detection of cardiac amyloidosis in patients with left ventricular hypertrophy and impact on prognosis.

BACKGROUND: Among diagnosis associated with left ventricular hypertrophy (LVH), cardiac amyloidosis (CA) is a progressive disease with poor prognosis. Early noninvasive identification is of growing clinical importance. The objective of our study was to integrate clinical, biologic, electrocardiographic and echocardiographic parameters to build a diagnostic score in patients with LVH.

METHODS AND RESULTS: One hundred and fourteen patients with LVH underwent a cardiac magnetic resonance (CMR) and a 99m Tc-hydroxymethylene-diphosphonate scintigraphy (99m Tc-HMDP) allowing to discriminate three groups of diagnoses: CA (n = 50 including 31, 18 and 1 ATTR, AL and AA amyloidosis), hypertrophic cardiomyopathy (n = 19) and unspecific cardiomyopathy (n = 45). Seven continuous variables associated with CA (systolic arterial pressure <130 mmHg; PR duration >200 ms; Sokolow index <12 mV; diastolic left ventricular posterior thickness >13 mm; E/Ea ratio >10; global longitudinal strain > -12% and sum of basal longitudinal strain > -47%) were selected and dichotomized according to the best cutoff value to build the diagnostic score, which was validated in an independent cohort of 34 patients with LVH from aortic stenosis. The area under the ROC curve for the diagnosis of CA using the score was 0.933 (95%CI 0.889-0.978). The best cut off value for the score was 3 leading to a sensitivity of 90% and specificity of 81%. Area under the ROC curve for the score was 0.932 in the validation cohort. A diagnostic score >3 was associated with a poorest prognosis.

CONCLUSION: An integrated evaluation of 6 diagnostic factors including arterial blood pressure, ECG and echocardiographic parameters to build a diagnostic score is a simple and easily method to discriminate the 3 main CA in patients with LVH.