Abstract: Background: Mitral valve repair (MVR) could be a curative treatment for myxomatous mitral valve disease (MMVD) in dogs. Previous reports in medical treatment have suggested that Cavalier King Charles Spaniels (CKCS) might be more susceptible to developing MMVD than other breeds, but the breed-specific characteristics and the long-term outcomes of MVR are unclear. Hypothesis/Objectives: We investigated the differences in cardiac reverse-remodeling and survival for MVR in different breeds. Animals: We retrospectively analyzed the data of dogs with MMVD that underwent MVR from February 2017 to February 2019 at our center. Methods: Based on breeds, dogs were divided into three groups: Chihuahuas, CKCS, and Others. Thoracic radiographs and echocardiography were evaluated in the preoperative period and 6, 12, and 36 months post-surgery. Results: Our study included 444 dogs (Chihuahuas = 206, CKCS = 40, and Others = 198). CKCS group had significantly higher vertebral heart score, left atrial aortic root ratio, and diastolic left ventricular normalized dimension both pre- and post-surgery. The three-year survival rate for all-cause mortality derived by the Kaplan-Meier curve was not different among the three groups: 75%, 66%, and 67%, respectively (P = 0.12; Log-rank test). Conclusions and clinical importance: Postoperative reverse remodeling might differ, especially in CKCS. Thus, early surgical intervention might be better for improving reverse remodeling in CKCS. However, MVR improves survival in all breeds despite differences in heart size.
.jpg "Kentaro Kurogochi, DVM, PhD photo")
