Precise identification of underlying causes and key factors leading to pulmonary edema is essential for proper treatment and prognosis. In patients with congestive heart failure, non-cardiogenic pulmonary edema (NCPE) can be easily misleading to a diagnosis of cardiogenic pulmonary edema (CPE) when occurring simultaneously. However, there have been very few reports describing the differential characteristics between NCPE and CPE. Here, we report a retrospective study to determine the clinical characteristics of NCPE in dogs with symptomatic myxomatous mitral valve disease (MMVD).

Emergently referred dogs with MMVD showed severe acute respiratory distress caused by either CPE or NCPE. The detailed groups are as follows: CPE (n=49) and NCPE (n=45; acute respiratory distress syndrome [n=23], post-anesthetic events [n=6], aspiration [n=6], upper airway obstruction [n=4], neoplasia [n=4], acute pancreatitis [n=1], multiple plasma transfusion [n=1]). We have retrospectively compared clinical characteristics, including medical history, laboratory findings and diagnostic imaging, and survival outcome between the CPE and the NCPE groups.

Recurrent episodes of pulmonary edema in the medical history of the NCPE group (1.4±1.6) significantly outnumbered those of the CPE group (0.2±0.6) (p<0.01). The differences in SPO₂ (%; 93.1±4.5 vs. 97.5±2.0) and hematocrit (%; 39.4±6.0 vs. 43.3±3.7) were significantly less in the NCPE group (p<0.01) than the CPE group. Furthermore, the NCPE group showed higher levels of blood work parameters related to inflammatory responses compared to the CPE group (p<0.01): leukocytosis (WBCs, k/L;19.6±7.4 vs. 10.3±2.1) and C-reactive protein (CRP, mg/dL; 1.9±2.1 vs. 0.5±0.3). In contrast, the NCPE group exhibited significantly lower peak velocity of E wave (cm/s; 130.8±36.6 vs. 157±19.2) and survival outcome (%; 33.3 vs. 83.7) than the CPE group (p<0.01). The prevalent radiographic findings in the NCPE was unilateral asymmetrical opacities (68.9%), although bilateral diffuse pulmonary infiltration (75.5%) was more often observed in the CPE group (P<0.01). Simple logistic regression to identify survival predictors demonstrated a significant correlation with the lower SPO₂ level and the higher recurrent incidence of pulmonary edema (Cox-Snell’s R squared; 0.512 and 0.581, respectively) (p<0.01). These two predictors were also found to exert a significant effect on survival outcome in multiple logistic regression (Cox-Snell’s R squared, 0.689; p<0.05).

In summary, several clinical characteristics, in particular the SPO₂ level and the history of recurrent pulmonary edema, showed highly differential significance and strong correlation with survival outcome. Our retrospective study could provide insight into improving diagnosis and prognosis of NCPE developed in dogs with concurrent congestive heart failure.

Disclosures

No disclosures to report.