Valutazione dei biomarker cardiaci e rilievi elettrocardiografici in corso di piometra complicata da SIRS (Systemic Inflammatory Response Syndrome)

Systemic inflammatory response syndrome (SIRS) represents one of the main complications associated with canine pyometra, particularly in closed-cervix forms, and may lead to significant cardiovascular alterations related to endotoxemia, sepsis, and multiple organ dysfunction. In human medicine, several studies have demonstrated that SIRS and sepsis can induce myocardial injury, electrocardiographic abnormalities, and increased cardiac biomarkers; however, information available in veterinary medicine is still limited. Therefore, the aim of the present study was to evaluate possible cardiac involvement in bitches affected by closed-cervix pyometra through the assessment of clinical, hematological, biochemical, electrocardiographic parameters, and cardiac biomarkers including cardiac troponin I (cTnI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Thirty-five bitches with histologically confirmed closed-cervix pyometra (PYO group) and ten healthy bitches undergoing elective ovariohysterectomy (CTR group) were included in the study. Dogs in the PYO group had a mean age of 9.2 years and belonged to different breeds. All animals underwent complete physical examination, SIRS clinical scoring, hematobiochemical analysis, electrocardiographic evaluation, and serum measurement of cTnI and NT-proBNP concentrations. According to SIRS clinical scoring, pyometra patients were further classified as SIRS-positive (PYO- P) or SIRS-negative (PYO-N). The most frequently observed clinical signs in dogs affected by pyometra were lethargy, anorexia, and behavioral changes (85.7%), followed by polyuria/polydipsia (51.4%) and gastrointestinal signs (40%). The PYO group showed significantly higher body temperature, heart rate, respiratory rate, and leukocyte counts compared to the control group. The mean SIRS clinical score in the PYO group was 3.02 ± 1.01, and 88.57% of the dogs were classified as SIRS-positive. From a laboratory standpoint, dogs with pyometra showed significantly increased leukocyte count, ALT, ALP, and blood urea nitrogen concentrations, together with significantly lower serum albumin levels compared with controls, confirming the presence of marked systemic inflammation and metabolic alterations secondary to the disease. 4 Regarding cardiac biomarkers, serum cTnI concentrations were significantly higher in the PYO group compared with the CTR group (171.2 ± 69 vs 0.6 ± 0.26; p = 0.003). Similarly, SIRS-positive dogs showed significantly higher cTnI concentrations than SIRS-negative dogs (322.5 ± 77.2 vs 4.87 ± 6.85; p < 0.001). NT-proBNP levels were also significantly increased in the PYO group compared with controls (1.47 ± 0.42 vs 0.45 ± 0.13; p < 0.001), with higher concentrations observed in SIRS- positive subjects compared with SIRS-negative dogs (1.61 ± 0.37 vs 1.12 ± 0.27; p = 0.007). However, no statistically significant correlations were found between SIRS clinical scores and cardiac biomarker concentrations. Electrocardiographic analysis revealed a higher prevalence of rhythm and conduction abnormalities in dogs affected by pyometra complicated by SIRS. In particular, sinus tachyarrhythmias, ventricular arrhythmias, and, in some severely compromised patients, episodes of sinus bradycardia were observed. These findings were considered compatible with cardiovascular involvement secondary to endotoxemia, microcirculatory impairment, and the effects of pro-inflammatory cytokines on the myocardium. Overall, the results of this study suggest that closed-cervix canine pyometra is a complex systemic disease frequently associated with SIRS and concomitant cardiac involvement. The significant increase in cTnI and NT-proBNP concentrations, together with electrocardiographic abnormalities, supports the hypothesis of multifactorial myocardial distress characterized by both cellular injury and hemodynamic stress. Therefore, the combined evaluation of cardiac biomarkers and electrocardiography may represent a useful diagnostic and prognostic tool in the clinical management of dogs affected by pyometra and SIRS, allowing a more accurate assessment of cardiovascular and perioperative risk.