Role of 3D left ventricular end-systolic volume in risk stratification and outcome prediction in significant mitral regurgitation

Abstract Aims In the follow-up of patients with mitral regurgitation (MR), assessment of left ventricular (LV) dilatation using standard echocardiography often yields inconsistent results. We investigated whether measuring 3D LV end-systolic volume (3DLVESV) improves risk stratification in moderate or greater MR. Methods and results In the prospective 3D Echocardiography and Cardiovascular Prognosis in Mitral Regurgitation (3D-PRIME) study, 227 patients −142 with primary (PMR) and 85 secondary MR (SMR)- underwent 2D/3D echocardiography. 3DLVESV was increased if ≥41.5/35 mL/m², and LV end-systolic diameter (LVESD) enlarged if ≥39.8/34.8 mm in men/women. The primary outcome was a composite of MR progression towards intervention, death, or heart failure hospitalization (HFH). Death or HFH was a secondary outcome. At baseline, 28% of PMR and 54% of SMR patients had increased 3DLVESV. After 21 (15–25) months, increased 3DLVESV was associated with 1.9-fold (1.2–3.2) higher adjusted risk of the primary outcome in PMR, and 4.1-fold (1.6–10.7) higher risk of death or HFH in SMR (P < 0.05). 3DLVESV and LVESD concordantly identified LV dilatation in 20% of PMR patients and were discordant in 27%. Both patients with increased 3DLVESV only, and those with increased both 3DLVESV and LVESD, had high risk of the primary outcome after adjusting for recommendations for intervention in PMR: HR 7.1 (2.9–16.9) and 4.9 (2.1–11.1), respectively (P < 0.001). Conclusion Increased 3DLVESV is associated with a higher risk of adverse events in patients with significant MR. In PMR, evaluating LV dilatation using both 3DLVESV and LVESD may enhance risk stratification and aid in patient selection for close follow-up. ClinicalTrials.gov identifier NCT04442828, 17 April 2020.