Cardiology Resident University of Illinois Savoy, Illinois, United States
Abstract: Background- Patent ductus arteriosus (PDA) is the most common cardiac congenital defect in dogs and with timely correction carries a good prognosis. If closure is delayed, the risk for heart failure and death increase. This study evaluated the short-term hemodynamic effects of pimobendan in dogs with preclinical left-to-right shunting PDA.
Hypothesis- Pimobendan will provide hemodynamic benefits in dogs with left-to-right shunting PDA.
Animals- 17 dogs with preclinical PDA
Methods- For this prospective observational cohort study, patients were evaluated via physical examination, thoracic radiographs, quantitative N-terminal pro-brain natriuretic peptide, and transthoracic echocardiography. Dogs were eligible based on the following criteria: echocardiographic evidence of a PDA (left-to-right) regardless of anatomic classification, the presence of cardiomegaly defined as left atrial (LA) and left ventricular (LV) size exceeding the 95% predictive interval, and radiographic cardiomegaly (VHS > 10.5) without concurrent pulmonary edema. All patients received pimobendan (0.4-0.6 mg/kg/day divided into q 12 hr dosing). Re-evaluation of all tests was performed on day 7 prior to PDA closure. Data were assessed for normality using a Shapiro-Wilk test and pre- post variables were compared using a paired t test or a Wilcoxon signed-rank test when appropriate. A P < 0.05 was considered significant.
Results- No patients decompensated during the study and significant differences in VHS (-0.2), LA volume (-0.31 mL/kg), normalized LV diastolic (-0.45 mL/kg) and systolic (-0.54 mL/kg) volume, LV ejection fraction (+6.1 %), and NT-proBNP (-332 pmol/L) were observed.
Conclusion and Clinical Importance- Pimobendan may provide short-term hemodynamic benefit in preclinical PDA patients.
