Cardiac Troponins as Indicators of Acute Myocardial Damage in Dogs

Abstract

Cardiac troponin I (cTnI) and T (cTnT) have a high sequence homology across phyla and are sensitive and specific markers of myocardial damage. The purpose of this study was to evaluate the Cardiac Reader, a human point-of-care system for the determination of cTnT and myoglobin, and the Abbott Axsym System for the determination of cTnI and creatine kinase isoenzyme MB (CK-MB) in healthy dogs and in dogs at risk for acute myocardial damage because of gastric dilatationvolvulus (GDV) and blunt chest trauma (BCT). In healthy dogs (n 5 56), cTnI was below detection limits (,0.1 mg/L) in 35 of 56 dogs (reference range 0-0.7 mg/L), and cTnT was not measurable (,0.05 ng/mL) in all but 1 dog. At presentation, cTnI, CK-MB, myoglobin, and lactic acid were all significantly higher in dogs with GDV (n 5 28) and BCT (n 5 8) than in control dogs (P , .001), but cTnT was significantly higher only in dogs with BCT (P 5 .033). Increased cTnI or cTnT values were found in 26 of 28 (highest values 1.1-369 mg/L) and 16 of 28 dogs (0.1-1.7 ng/mL) with GDV, and in 6 of 8 (2.3-82.4 mg/L) and 3 of 8 dogs (0.1-0.29 ng/mL) with BCT, respectively. In dogs suffering from GDV, cTnI and cTnT increased further within the first 48 hours (P , .001). Increased cardiac troponins suggestive of myocardial damage occurred in 93% of dogs with GDV and 75% with BCT. cTnI appeared more sensitive, but cTnT may be a negative prognostic indicator in GDV. Both systems tested seemed applicable for the measurement of canine cardiac troponins, with the Cardiac Reader particularly suitable for use in emergency settings.

ORIGINAL RESEARCH: Electrophoretic fractionation of creatine kinase isoenzymes and macroenzymes in clinically healthy dogs and cats and preliminary evaluation in central neurologic disease

“…Although this method does not identify specific isoenzymes or isoforms, it provides an estimate of CK‐MM activity, which is responsible for the majority of plasma CK activity in many species. CK‐MB can be measured by immunoenzymatic methods designed for diagnostic purposes in people with myocardial diseases; these methods have also been used in dogs, although definitive validation studies have not been done 5–7 . By contrast, CK‐BB and macroenzymes can be measured only by more expensive and labor‐intensive methods, such as chromatography, immunoprecipitation, immunoinhibition, differential enzyme activation, and electrophoresis 3 …”

“…The limited information about CK isoenzymes in dogs is focused on CK‐MM and CK‐MB 5–13 . Only one study reported serum CK‐BB activity in dogs with neurologic disease 12 .…”

“…In addition, CK‐MB was also present in small amounts in supernatants from homogenized heart, in agreement with another study 9 . The evaluation of CK‐MB in pathologic conditions is outside the scope of this study, but our results suggest that the clinical utility of CK‐MB measurement is low compared with that of other biomarkers 6 …”

Preoperative thoracic radiographic findings in dogs presenting for gastric dilatation‐volvulus (2000–2010): 101 cases

“…Myocardial ischemia secondary to hypoperfusion, reperfusion injury, and oxygen‐free radical production is thought to occur . This has been supported by showing an increase in cardiac troponins in GDV patients . These insults to the myocardium during the disease process may be exacerbating nonclinical underlying heart disease, making it difficult for the patient to compensate.…”

INVITED REVIEW: Routine and specialized laboratory testing for the diagnosis of neuromuscular diseases in dogs and cats

“…Genes distinct from those encoding skeletal muscle isoforms encode cardiac troponin I, 27 and this troponin is a marker of myocardial cellular injury. Thus, cardiac troponins are more specific for cardiac damage, compared with the specificity of LDH or CK activity or myoglobin concentration 28–30 . Furthermore, cardiac troponin concentrations are generally not affected by nonspecific types of skeletal muscle damage, including trauma, IM injections, or strenuous exercise.…”