Effect of metastatic calcification on complication rate and survival in 74 renal transplant cats (1998-2020)

To report the incidence of metastatic calcification in cats with renal failure presenting for renal transplantation, and to determine if metastatic calcification detected prior to renal transplantation is associated with complication rates and patient survival.

Retrospective case series.

Seventy-four cats.

In imaging studies, 178 feline renal transplant recipients from 1998 to 2020 were evaluated for metastatic calcification. Demographic, clinicopathological data, intraoperative complications, postoperative complications, need for hemodialysis, and survival times were recorded. Exclusion criteria were cats lacking imaging reports and cats with gastric, renal, or tracheal/bronchial calcification alone. Univariable and multivariable analyses were performed to determine variables that were independently associated with survival. Kaplan-Meier analysis was used to generate survival plots and estimate median survival times with a 95% confidence interval (CI).

Seventy four of 178 cats met the inclusion criteria. Fifteen of 74 (20.3%) cats had metastatic calcification prior to renal transplantation. Twelve of 74 (16.2%) cats developed calcification following transplantation, and 47 of 74 (63.5%) cats had no calcification during the study period. Median follow-up time was 472 days, with a range of 0-1825 days. Cats with pretransplant calcification had shorter median survival times (147 days) than cats without calcification (646 days) (p = .0013). Metastatic calcification pretransplant was associated with an increased risk of death by 240% (95% CI, 1.22-4.71).

Metastatic calcification in renal transplant cats is a negative prognostic indicator and is associated with decreased survival times.

These findings may help guide therapeutic recommendations and owner expectations in cats undergoing renal transplantation.