Prognostic characteristics of preoperative serum total bilirubin concentration in myxomatous mitral valve disease in dogs undergoing mitral valve repair.

摘要

BACKGROUND: While serum total bilirubin concentration (Tbil) has emerged as a potential prognostic marker in dogs with myxomatous mitral valve disease (MMVD) after mitral valve repair (MVR), its dose-response relationship and underlying pathophysiological mechanisms remain unclear. HYPOTHESIS/OBJECTIVES: To characterize the dose-response relationships between preoperative Tbil and 2-year all-cause mortality after MVR and explore the role of right-sided cardiac compromise. ANIMALS: Two thousand sixty-three (cohort A) and 301 (cohort B) dogs with MMVD undergoing MVR at a single center. METHODS: This retrospective cohort study used multivariable Cox regression to assess the association between Tbil and 2-year mortality in cohort A. Cohort B evaluated relationships among Tbil, hepatic congestion, and right-sided overload. RESULTS: In cohort A, preoperative Tbil showed a linear positive association with 2-year all-cause mortality even within reference interval (ie, adjusted hazard ratio [0.3 vs. 0.1 mg/dL]: 1.33; 95% CI, 1.04-1.70). This association disappeared in dogs surviving beyond 30 days. Furthermore, higher preoperative Tbil levels were associated with an increased incidence of cardiac-related 30-day deaths in cohort A, and with right-sided cardiac overload at discharge in cohort B, which resolved by one month postoperatively. Hepatic congestion was associated with right-sided overload but not Tbil levels. CONCLUSIONS AND CLINICAL IMPORTANCE: Subtle preoperative Tbil elevations were associated with short-term all-cause mortality and transient right-sided overload, warranting careful interpretation even within reference intervals. However, the pathophysiological mechanism linking Tbil to postoperative prognosis remains to be elucidated. ABSTRACT TRANSLATED TO JAPANESE: ビリルビン (Tbil) は、 (MVR) の (MMVD) のにおけるのがされているが、そのおよびはとしてである。 Tbil と MVR 2とのをらかにし、とのをすること。で MVR をけた MMVD の、コホートA 2,063 およびコホートB 301 。とろきコホートでは、コホートA において Tbil と 2 とのを Cox モデルによりした。コホート B では、 Tbil とうっおよびのをした。コホートA において、 Tbil はであっても2とのをした (ハザード [0.3  0.1 mg/dL]: 1.33、95%  1.04-1.70)。このは 30をえてしたではした。さらに、 Tbil は、コホートA における 30 のの、およびコホートB におけるののとし、このは 1 かまでにした。うっはとしたが、 Tbil とはしなかった。とのわずかな Tbil は、およびのとしており、のであってもになをつがある。ただし、 Tbil とをびつけるはとしてらかではない。. Myxomatous mitral valve disease is the most common acquired cardiac disease in small-breed dogs, and mitral valve repair (MVR) can prolong survival. We investigated whether preoperative serum total bilirubin (Tbil), a marker that might reflect hepatic and right-sided cardiac congestion, is associated with outcome after MVR, because its prognostic role and underlying mechanism had not been clarified. We studied 2063 dogs (survival analysis) and 301 dogs (right-sided cardiac assessment) at a single center. The key findings were as follows: Higher preoperative Tbil was associated with increased 2-year all-cause mortality in a dose-dependent manner, even when values were within the reference interval. This association was driven mainly by deaths within the first 30 days after surgery and was no longer evident in dogs surviving beyond 30 days. Higher preoperative Tbil was also associated with transient right-sided cardiac overload in the early postoperative period, which resolved within about one month. Hepatic congestion was associated with right-sided cardiac overload but not with Tbil concentration. Preoperative Tbil, a simple and inexpensive measurement, might help identify higher-risk dogs; these single-center findings warrant prospective validation.