Abstract 19126: Cardiac AL Amyloidosis with or without Significantly-increased Left Ventricular Wall Thickness

Background: Cardiac involvement is a major prognostic factor in AL amyloidosis. Poor survival of cardiac amyloidosis (CAm) have been reported previously. Recently, many data demonstrate methods detecting early CAm. However, data regarding the clinical meanings of early CAm without significantly-increased LV wall thickness (LVWT) are still lacking. So, we investigated clinical findings of early CAm. Methods: Total 124 patients were diagnosed as AL amyloidosis by positive Congo red stain in tissue. Among them, 46(37.1%) patients satisfied the classic definition of CAm; mean LVWT>12mm without other cardiac cause. And, 19(15.3%) patients had LVWT≤12mm, but were diagnosed as CAm with cardiac biopsy or cardiac MRI. The number of patients without evidence of CAm was 51(41.1%). We compared the echocardiographic parameters as well as survival among three groups. Median follow-up duration was 14.5 months. Results: Mean LVWT was higher in the group of classic definition compared to the group of minor LVWT [14(13∼16) vs 11(9∼12)mm, p<0.003]. However, LV ejection fraction, LA volume index, and e’ were not different between the group of classic definition and of minor LVWT [55.3(46.5∼62.5) vs 54(48∼61)%, p=0.908, 44.0(36.7∼55.1) vs 45.9 (37.7∼58.6)ml/m 2 , p=0.486, 0.04(0.03∼0.06) vs 0.04(0.04∼ 0.05)m/sec, p=0.796]. These parameters were better in the group of no cardiac involvement [65(61∼69)%, 23.5(18.1∼29.7)ml/m 2 , 0.08(0.06∼0.09)m/sec, all p<0.003]. Overall survival rates showed similar pattern. The group of no cardiac involvement showed better prognosis compared to the other two groups (p<0.003). However, between the two groups of CAm, the survival curves were not different (p=0.361). Conclusions: The parameters in echocardiography and survival rates were different according to the presence of CAm, not by the degree of LVWT. The classic definition of cardiac involvement in AL amyloidosis may need to be re-evaluated to reflect more accurate clinical findings.