Abstract OBJECTIVES The clinical importance of optimal post-repair mitral valve diastolic performance is increasingly being recognized. The haemodynamic effect of a partial annuloplasty band implantation, in comparison to a full ring, remains insufficiently explored. METHODS Patients undergoing mitral valve repair for pure degenerative disease between 2011 and 2019 at 2 experienced heart valve centres were eligible for inclusion. Exclusion criteria were concomitant procedures other than tricuspid valve repair and ablation procedures for atrial fibrillation. Pre-discharge and follow-up echocardiograms (1–4 years after surgery) were analysed to assess haemodynamic mitral valve performance. RESULTS Of 535 patients meeting the inclusion criteria, 364 (68.0%) patients underwent full annuloplasty ring and 171 (31.0%) partial band implantation. On predischarge echocardiogram, post-repair mitral valve gradient and area did not differ between groups [2.89 mmHg (IQR 2.26–3.72) vs 2.60 mmHg (IQR 1.91–3.55), P = 0.19 and 1.98 cm2 (IQR 1.66–2.46) vs 2.03 cm2 (IQR 1.55–3.06), P = 0.15]. However, multivariable linear regression analysis demonstrated band annuloplasty as a determinant of larger valve area (coefficient 0.467 cm2, standard error 0.105, P < 0.001). On multivariable analysis, no significant impact on post-repair gradient was observed (–0.370 mmHg, standard error 0.167, P = 0.36). At follow-up, the differences between groups disappeared and multivariable regression analysis failed to demonstrate a significant impact of annuloplasty device type on mitral valve gradient (coefficient –0.095 mmHg, standard error 0.171, P = 1.00) or area (coefficient –0.085 cm2, standard error 0.120, P = 1.00). These results were confirmed with a linear mixed model analysis. CONCLUSIONS Partial band annuloplasty was related to an improved haemodynamic profile directly after valve repair for degenerative disease but the effect was short-lived. Our results suggest that the type of annuloplasty device has no durable impact on diastolic valve performance.