Cardiac CT assessment of left ventricular mass in mid-diastasis and its prognostic value

Abstract

Aims: To determine the influence of cardiac motion on measurements of left ventricular (LV) mass obtained with 64-slice computed tomography (CT) and to elucidate the prognostic value of LV mass on major adverse cardiac events (MACE) and all-cause mortality. Increased LV mass has been linked with MACE. Although Cardiac CT allows measurement of LV anatomy, it is susceptible to motion artefacts often requiring image acquisition during diastasis. There is a need to understand variability in LV mass measurements across phases of the cardiac cycle, and whether mid-diastolic measurements have prognostic value.

Methods and results: The study comprised two equally sized cohorts of patients that had undergone retrospectively gated cardiac CT: patients who had MACE and/or all-cause death at follow-up and a matched (age, sex, and risk factors) event-free cohort. LV mass was measured at mid-diastole, end-diastole, and end-systole. Correlation and agreement between phases were determined. The incremental value of mid-diastolic hypertrophy (LVH) over the National Cholesterol Education Programme (NCEP) risk was performed for LV mass indices normalized to body surface area (LVMI_BSA) or weight (LVMI_Weight). Of 166 patients, 31.3% experienced MACE and 28.9% died of any cause (follow-up 22.9 ± 13.4 months). LV mass at all cardiac phases were strongly correlated (r > 0.94). Mean mid-diastolic LVMI_BSA was higher in the cohort with events (93.7 vs. 80.7 g/m², P= 0.008) as was LVMI_Weight (2.26 vs. 1.88 g/kg, P = 0.001). LVMI_BSA and LVMI_Weight had prognostic value incremental to NCEP with 1.85 and 2.47 hazard ratios, respectively.

Conclusions: Measurement of LV mass can be obtained by cardiac CT images obtained at mid-diastasis. LV mass measurements obtained at mid-diastasis have prognostic value.

Keywords: LV mass; computed tomography; prognosis; prospective gating.