Proposal of a Novel Index for Selection of Optimal Annuloplasty Ring Size for Tricuspid Annuloplication

Abstract

Optimal ring size in tricuspid annuloplasty (TAP) surgery to treat functional tricuspid regurgitation (TR) was investigated because optimal ring size remains undefined. Sixty seven patients who underwent TAP at our institution were retrospectively studied. Tricuspid Annuloplasty Ring size Index (TARI) was defined as implanted tricuspid annuloplasty ring size divided by body surface area (BSA). Different TARI cut-off values were tested to determine which value produced the greatest difference in TR improvement (TRI=preoperative minus postoperative TR grade) between patients with TARI smaller (group S) and larger (group L) than the cut-off. Group S was also subdivided by ring type: Cosgrove rings (SC) and MC3 rings (SM). TARI and TRI were negatively correlated (r=-0.307). A TARI threshold of 18.9 mm/m(2) produced the greatest and most significant difference (P<0.0005) in TRI. Defining groups S and L using this threshold, TRI was significantly greater for group S (1.77 ± 0.80) than for group L (0.97 ± 0.83); P <0.0005. There was no difference in TRI between groups SC and SM. A novel index TARI that normalizes tricuspid annuloplasty ring size by BSA was developed. Choosing ring size to make TARI <18.9 mm/m(2) is likely to be better than setting an upper limit of absolute ring size in the surgical treatment of TR.