NONINVASIVE ASSESSMENT OF LEFT VENTRICULAR STRUCTURAL CHANGES IN APOLIPOPROTEIN A-I (LEU75PRO) BY ACOUSTIC DENSITOMETRY

Background: Hereditary amyloidosis are late-onset autosomal dominant disorders characterized by amyloid deposition in various tissues. Among them, Apolipoprotein A-I amyloidosis (APOA-I amyloidosis Leu75Pro) is a rare, autosomal dominant condition in which renal, hepatic, and testicular involvement has been demonstrated. No data are available about deposition of amyloid in cardiac tissue in patients with APOA-I amyloidosis(Leu75Pro). We recently reported an increase in LV mass as well as slight, but significant impairment, in LV systolic and diastolic function in these patients. Aim of the study was to evaluate structural changes in myocardium in patients with APOA-I amyloidosis by integrated backscatter analysis (IBS). Patients and Methods: In 104 patients with APOA-I amyloidosis (age 52 ± 16 years, 56 F) and in 104 subjects matched for age, sex, BMI and clinic BP, standard echocardiography were assessed. In all subjects IBS was analyzed by acoustic densitometry. The signal was sampled with a ROI placed in the mid portion of the interventricular septum (IVS) and of the posterior wall (PW). Results: LVMI was significantly higher in patients with APOA-I amyloidosis than controls (35.6 ± 12.8 g/m2.7 vs. 32.7 ± 7.3 g/m2.7 respectively, p < 0.05).The ratio of transmitral E velocity (E) to mitral annular E velocity (Em) was significantly greater in amyloidosis (9.7 ± 4.2 vs. 8.0 ± 2.1, p < 0.005). Ejection fraction, fractional shortening and midwall fractional shortening were significantly lower in amyloidosis (64.0 ± 7.0 vs. 66.3 ± 5.9, p < 0.05; 37.2 ± 8.3 vs. 40.2 ± 7.4, p < 0.005 and 19.2 ± 3.8 vs. 20.8 ± 3.0, p < 0.001, respectively). In amyloidosis a significant increase in IBS reflectivity was observed in comparison with controls, at the level of both IVS and PW, (62.8 ± 15% vs. 53.6 ± 9% and 49.6 ± 8% vs. 41.3 ± 9%, p < 0.01, respectively). Cyclic variation of IBS was significantly lower in APOA-I than controls (IVS: 20 ± 6% vs. 22 ± 7%; PW: 27 ± 9% vs. 31 ± 11%, p < 0.05). The differences remained significant after adjusting for creatinine clearance. Conclusion: In patients with APOA-I amyloidosis (Leu75Pro) we observed, in addition to an increase in LVMI and slight impairments in LV systolic and diastolic function, significant differences in IBS that might reflect an involvement of the myocardium in these patients. These results, obtained in a relatively wide sample of patients, may add significant information to the clinical features of this relatively rare genetic disorder