2017 ACVIM Forum Research Abstract Program

Our objective is to elucidate the influence of changes in diastolic aortic pressure and aortic compliance on the fractional shortening (FS%) in dogs that undergo patent ductus arteriosus (PDA) occlusion. 62-client owned dogs that underwent percutaneous PDA occlusion were retrospectively used for our study. The dogs were evaluated using echocardiography and a catheter for the measurement of their direct blood pressure during PDA occlusion. The diameter of descending aorta was measured using digital fluoroscopic cine loops. After PDA occlusion, the systolic blood pressure did not change; however, pulse pressure significantly decreased (P < 0.01) and diastolic blood pressure (DAP) significantly increased (P < 0.01). In a univariate analysis (n = 49), the low postoperative FS% was associated with an older age (P < 0.05), the increased postoperative diastolic blood pressure, and decreased pulse pressure (both with P < 0.01). In a multivariate analysis (n = 49), low postoperative FS% was associated with an older age (P < 0.05) and a decreased postoperative pulse pressure (P < 0.05). The diameter of the descending aorta significantly increased both in systole and diastole (both with P < 0.01) and the aortic FS% was significantly decreased (P < 0.05) just after PDA occlusion. In conclusion, left ventricle might not be able to contract after PDA occlusion because of increased DAP and decreased aortic compliance, i.e., the aortic valve more strongly closed and the aorta was rapidly dilated like a rupturing balloon due to trapping a large amount of blood into aorta. Of 146 canine HA cases identified during this time period, 12 (8%) also experienced CHF. Eight of these dogs had chronic mitral valve disease; the other 4 had dilated cardiomyopathy. Five of the 12 dogs experienced CHF after the first injection of DOCP; 3 of these had known pre-existing heart disease. The median time between the DOCP and CHF was 11 days (range 1-29 days).