Mitral valve repair in a dog with a modified taut-line hitch knot technique.

Objective: To report the outcome of a dog with severe mitral regurgitation (MR) treated with open-heart surgery using the modified taut-line hitch (modified TLH) knot technique.

Methods: A 9-year-old, 8.8-kg intact male Cavalier King Charles Spaniel was referred for clinical signs of congestive heart failure secondary to severe mitral regurgitation. The dog underwent mitral valve repair under cardiopulmonary bypass. On echocardiographic examination, the left atrial-to-aortic root ratio (LA/Ao) was 2.87, and the normalized left ventricular internal diameter in diastole (LVIDdN) was 2.43. After cardiac arrest, semi-circular suture annuloplasty and chordal reconstruction using ePTFE sutures were performed. Artificial chordae lengths were adjusted using the modified TLH knot technique.

Results: Vertebral heart scores (VHS) were 15.0 (preoperatively), 12.0 (3 months), 12.3 (6 months) and 12.6 (1 year). LVIDd values were 46.1 mm (preoperatively), 33.3 mm (3 months), 34.1 mm (6 months) and 37.1 mm (1 year). LA/Ao ratios were 2.87 (preoperatively), 1.78 (3 months), 1.90 (6 months) and 1.97 (1 year). The patient remained on pimobendan (0.25 mg/kg every 12 h) at the intermediate-term follow-up, and from the 1-year evaluation, furosemide (2 mg/kg once daily) was prescribed in addition to pimobendan. At the long-term follow-up, no clinical signs of congestive heart failure were observed.

Conclusion: Mitral valve repair using the modified TLH knot technique was associated with control of clinical signs and a reduction in medical therapy requirements during long-term follow-up in a dog with severe MR.