Abstract 5929: Evaluation of Myocardial Substrate with MRI Late Gadolinium Enhancement Allows for Earlier Detection of Cardiac Involvement Compared with Morphological Assessment in Primary AL Amyloidosis
Objective: In AL amyloidosis, early detection of cardiac involvement is desirable because of prognostic and therapeutic implications. Recent pilot MRI studies have demonstrated that late gadolinium enhancement (LGE) is a common finding in cardiac amyloidosis (CA) and reflects interstitial expansion due to amyloid infiltration. However it is not known whether evaluation of the myocardial substrate via LGE MRI may allow for earlier detection of CA compared with morphological assessment on the basis of increased left ventricular thickness (LVT).
Methods: Between January 2006 and December 2007, 100 patients with confirmed AL amyloidosis underwent LGE MRI at our institution to evaluate for CA. Morphological evidence of CA was considered to be present when LVT was increased (mean of septum and inferolateral wall > 12 mm). LGE images were analyzed for presence and pattern of LGE. Clinical data was also reviewed.
Results: Increased LVT was present in 69 patients. Abnormal LGE images were present in 76 patients (global diffuse transmural or subendocardial LGE in 43, suboptimally nulled myocardium in 18, and focal patchy LGE in 15 patients). LGE was present in 21 of 22 patients with a diagnosis of CA on cardiac biopsy. Seven patients (10%) with increased LVT did not have LGE. Conversely of 31 pts with normal LVT, 14 (45%) had abnormal LGE on MRI (usually suboptimally nulled myocardium or focal patchy LGE) and also had significantly higher incidence of low voltage ECG (50% vs. 0%), lower absolute limb lead voltage (6.5±3 vs. 9.7±2.6 mm), increased RV thickness (4.9±1.1 vs. 4.1±1) and higher BNP (316±376 vs. 107±103) compared to 17 patients without LGE (Table 1⇓).
Conclusions: MRI LGE is common in patients with CA and evaluation of the myocardial substrate using this technique may allow for earlier detection of cardiac involvement in AL amyloidosis compared with morphological assessment on the basis of increased LVT.