Plasma N‐Terminal Probrain Natriuretic Peptide, Vascular Endothelial Growth Factor, and Cardiac Troponin I as Novel Biomarkers of Hypertensive Disease and Target Organ Damage in Cats

BACKGROUND In the absence of ocular target organ damage (ocular-TOD), diagnosis of hypertension is challenging in cats. Biomarkers would provide additional support for the diagnosis of hypertension. HYPOTHESIS Vascular endothelial growth factor (VEGF), N-terminal probrain natriuretic peptide (NT-proBNP), cardiac troponin I (cTnI), and urine protein-to-creatinine ratio (UPC) are predictors of systemic hypertension, will be increased in cats with hypertension with or without ocular-TOD, and will decrease with antihypertensive treatment. METHODS Plasma VEGF, NT-proBNP, and cTnI concentrations and UPC were determined in healthy geriatric cats, normotensive cats with chronic kidney disease (CKD), hypertensive cats with evidence of hypertensive retinopathy (HT-ocular-TOD), and hypertensive cats without hypertensive ocular-TOD (HT-noTOD). Comparisons among groups were performed. Multivariable binary logistic regression models were built to identify independent biomarkers of hypertension and ocular-TOD. Receiver operator characteristic (ROC) curves were drawn to assess clinical use. RESULTS Cats with HT-ocular-TOD had significantly higher VEGF than all other groups (P < .05) and significantly higher NT-proBNP than healthy cats (P < .001). Healthy cats had significantly lower cTnI than all other groups (P < .05). No differences were found among groups for UPC (P = .08). Cardiac troponin I and VEGF were independent predictors of hypertension (P < .05), but none of the biomarkers were independent predictors of ocular-TOD. N-terminal probrain natriuretic peptide concentrations decreased with antihypertensive treatment (P < .001). The ROC curves indicated that none of the biomarkers met the criteria to function as diagnostic tests for the diagnosis of hypertension or associated ocular-TOD. CONCLUSIONS AND CLINICAL SIGNIFICANCE Despite statistical significance and changes with ocular-TOD, antihypertensive treatment, or both, VEGF, NT-proBNP, and cTnI did not function as useful diagnostic tests for hypertension. Persistently increased systolic blood pressure (SBP) measurements in combination with fundoscopy remains the preferred method for diagnosis of feline hypertension.