Digital blood flow and plasma endothelin concentration in clinically endotoxemic horses

Nicola J. Menzies-Gow MA, VetMB, PhD1, Simon R. Bailey BVMS, PhD2, Kim Stevens MSc3, Lisa Katz DVM4, Jonathan Elliott MA, VetMB, PhD5, and Celia M. Marr BVMS, MVM, PhD6,7
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  • 1 Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, United Kingdom.
  • | 2 Department of Veterinary Basic Sciences, Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, United Kingdom.
  • | 3 Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, United Kingdom.
  • | 4 Department of Veterinary Basic Sciences, Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, United Kingdom.
  • | 5 Department of Veterinary Basic Sciences, Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, United Kingdom.
  • | 6 Department of Veterinary Clinical Sciences, Royal Veterinary College, Hatfield, Hertfordshire AL9 7TA, United Kingdom.
  • | 7 Present address is Beaufort Cottage Equine Hospital, Rossdale and Partners, Cotton End Rd, Exning, Newmarket, Suffolk CB8 7NN, United Kingdom.

Abstract

Objective—To measure plasma endothelin-1 (ET-1) concentrations and digital blood flow in clinically endotoxemic horses.

Animals—To measure plasma endothelin-1 (ET-1) concentrations and digital blood flow in clinically endotoxemic horses.

Procedure—On days 2 and 5 following surgery, Doppler ultrasonographic digital arterial blood flow measurements were obtained. Hematologic and biochemical analyses were performed, and plasma concentrations of ET-1 and endotoxin (lipopolysaccharide) were determined. A scoring system based on 9 clinical variables was used to assign horses to group B (quartile with greatest cumulative score) or group A (remaining 3 quartiles). Follow-up at 2.5 years was obtained by telephone questionnaire.

Results—For all horses on day 2, median (interquartile values) plasma ET-1 concentrations were 1.4 (0.8, 1.7) pg/mL, whereas on day 5, plasma ET-1 concentrations were 1.0 (0.5, 1.6) pg/mL. On day 2, digital blood flow was 0.057 (0.02, 0.07) mL/min in group A horses and 0.035 (0.02, 0.03) mL/min in group B horses. On day 5, plasma ET-1 concentration was significantly (73%) higher in group B horses, compared with group A horses. Thirty of 36 horses were alive at 2.5 years; group A horses were more likely to have survived (odds ratio, 25; 95% confidence interval, 2.4 to 262). Significant associations were found between an increase in digital pulses, hoof wall temperatures, or both and increased digital blood flow (0.14 vs 0.04 mL/min) on day 2 and increased digital arterial diameter (0.32 vs 0.23 cm) on day 5.

Conclusions and Clinical Relevance—Horses with more severe endotoxemia had decreased digital blood flow, increased plasma ET-1 concentrations, and decreased long-term survival. (Am J Vet Res 2005;66:630–636)

Abstract

Objective—To measure plasma endothelin-1 (ET-1) concentrations and digital blood flow in clinically endotoxemic horses.

Animals—To measure plasma endothelin-1 (ET-1) concentrations and digital blood flow in clinically endotoxemic horses.

Procedure—On days 2 and 5 following surgery, Doppler ultrasonographic digital arterial blood flow measurements were obtained. Hematologic and biochemical analyses were performed, and plasma concentrations of ET-1 and endotoxin (lipopolysaccharide) were determined. A scoring system based on 9 clinical variables was used to assign horses to group B (quartile with greatest cumulative score) or group A (remaining 3 quartiles). Follow-up at 2.5 years was obtained by telephone questionnaire.

Results—For all horses on day 2, median (interquartile values) plasma ET-1 concentrations were 1.4 (0.8, 1.7) pg/mL, whereas on day 5, plasma ET-1 concentrations were 1.0 (0.5, 1.6) pg/mL. On day 2, digital blood flow was 0.057 (0.02, 0.07) mL/min in group A horses and 0.035 (0.02, 0.03) mL/min in group B horses. On day 5, plasma ET-1 concentration was significantly (73%) higher in group B horses, compared with group A horses. Thirty of 36 horses were alive at 2.5 years; group A horses were more likely to have survived (odds ratio, 25; 95% confidence interval, 2.4 to 262). Significant associations were found between an increase in digital pulses, hoof wall temperatures, or both and increased digital blood flow (0.14 vs 0.04 mL/min) on day 2 and increased digital arterial diameter (0.32 vs 0.23 cm) on day 5.

Conclusions and Clinical Relevance—Horses with more severe endotoxemia had decreased digital blood flow, increased plasma ET-1 concentrations, and decreased long-term survival. (Am J Vet Res 2005;66:630–636)