Prognostic value of left ventricular hypertrophy assessed with ¹⁵O-water positron emission tomography

Left ventricular (LV) hypertrophy is associated with adverse cardiac outcomes. LV mass index (LVMi) and interventricular septal wall thickness (WT) can be derived from ¹⁵O-water positron emission tomography (PET), but their prognostic value is unknown. We aimed to assess the prognostic value and test-retest repeatability of PET-derived LV hypertrophy metrics in patients evaluated for suspected coronary artery disease (CAD).

We retrospectively included 783 consecutive patients referred for rest-stress PET. LVMi and WT were determined on non-ECG-gated resting ¹⁵O-water PET scans. Subjects were stratified by previous heart failure (HF) diagnosis and patients with known hypertrophic/infiltrative cardiomyopathy were excluded. The primary outcome was major adverse cardiac events (MACE: cardiovascular death or acute HF). The prognostic value of LV hypertrophy measurements was evaluated using Cox hazard ratios (HR [95% confidence interval]). Test-retest repeatability was evaluated in prospective data from 21 patients with repeated PET scans.Patients with known HF but no hypertrophic/infiltrative cardiomyopathy (18%) had significantly higher LVMi (P < 0.0001) and WT (P = 0.0015) compared to subjects without HF (82%). Among patients without HF, 30 experienced MACE during a median 3.8 year follow up. Both LVMi (HR 1.04 [1.02-1.06] per g/m², P < 0.0001) and WT (HR 1.36 [1.10-1.68] per mm, P = 0.0045) independently predicted MACE after adjustment for sex, age and myocardial flow reserve. Test-retest repeatability was high, with no significant bias.

PET LV hypertrophy metrics can be robustly quantified from routine ¹⁵O-water PET and provide prognostic information beyond myocardial perfusion.