Incremental Utility of First-Pass Perfusion CMR for Prognostic Risk Stratification of Cancer-Associated Cardiac Masses.

Overview

abstract

BACKGROUND: Cardiac magnetic resonance (CMR) differentiates cardiac metastasis (C_MET) and cardiac thrombus (C_THR) based on tissue characteristics stemming from vascularity on late gadolinium enhancement (LGE). Perfusion CMR can assess magnitude of vascularity; utility for cardiac masses (C_MASS) is unknown. OBJECTIVES: The study sought to determine if perfusion CMR provides diagnostic and prognostic utility for C_MASS beyond binary differentiation of C_MET and C_THR. METHODS: The population comprised adult cancer patients with C_MASS on CMR; C_MET and C_THR were defined using LGE-CMR: C_MASS+ patients were matched to C_MASS- control subjects for cancer type/stage. First-pass perfusion CMR was interpreted visually and semiquantitatively for C_MASS vascularity, including contrast enhancement ratio (CER) (plateau vs baseline) and contrast uptake rate (CUR) (slope). Follow-up was performed for all-cause mortality. RESULTS: A total of 462 cancer patients were studied, including patients with (C_MET = 173, C_THR = 69) and without C_MASS on LGE-CMR. On perfusion CMR, CER and CUR were higher within C_MET vs C_THR (P < 0.001); CUR yielded better performance (AUC: 0.89-0.93) than CER (AUC: 0.66-0.72) (both P < 0.001) to differentiate LGE-CMR-evidenced C_MET and C_THR, although both CUR (P = 0.10) and CER (P = 0.01) typically misclassified C_MET with minimal enhancement. During follow-up, mortality among C_MET patients was high but variable; 47% of patients were alive 1 year post-CMR. Patients with semiquantitative perfusion CMR-evidenced C_MET had higher mortality than control subjects (HR: 1.42 [95% CI: 1.06-1.90]; P = 0.02), paralleling visual perfusion CMR (HR: 1.47 [95% CI: 1.12-1.94]; P = 0.006) and LGE-CMR (HR: 1.52 [95% CI: 1.16-2.00]; P = 0.003). Among patients with C_MET on LGE-CMR, mortality was highest among patients (P = 0.002) with lesions in the bottom perfusion (CER) tertile, corresponding to low vascularity. Among C_MET and cancer-matched control subjects, mortality was equivalent (P = NS) among patients with lesions in the upper CER tertile (corresponding to higher lesion vascularity). Conversely, patients with C_MET in the middle (P = 0.03) and lowest (lowest vascularity) (P = 0.001) CER tertiles had increased mortality. CONCLUSIONS: Perfusion CMR yields prognostic utility that complements LGE-CMR: Among cancer patients with LGE-CMR defined C_MET, mortality increases in proportion to magnitude of lesion hypoperfusion.