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. Surgical mitral valve repair is the gold standard treatment for degenerative valve disease with excellent clinical outcomes 1.