Clinical features of canine pulmonary veno‐occlusive disease and pulmonary capillary hemangiomatosis

Abstract

BackgroundHistologic features of pulmonary veno‐occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) have been described in dogs but without a thorough clinical description.ObjectivesTo report the clinical features, diagnostics, treatment, and outcome of dogs with histologic evidence of PVOD and PCH.AnimalsFifteen pet dogs meeting histopathologic criteria of PVOD (occlusive remodeling of small‐sized to medium‐sized pulmonary veins) or PCH (alveolar capillary proliferation and congestion), or both.MethodsMedical records of dogs with PVOD and PCH identified based on histopathologic features between 2003 and 2017 were retrospectively reviewed.ResultsFifteen dogs met inclusion criteria of a histologic diagnosis of PVOD or PCH or both. Dogs were older (median 11 years) with no apparent breed or sex predisposition. Dogs presented with acute clinical signs (median 3 days), usually respiratory distress. Thoracic radiography (available in 10 dogs) revealed right cardiomegaly and patchy or diffuse interstitial to alveolar patterns, with 9 dogs having a normal left cardiac silhouette. In 5 dogs tested, pulmonary arterial hypertension (PAH) was documented. In all 3 dogs, thoracic computed tomography scans showed pulmonary arterial enlargement and perivascular diffuse nodular ground‐glass opacities. Ten of 15 dogs died within 1 day; median survival was 3 days.Conclusions and Clinical ImportanceIn dogs with PAH, the inability to document left‐sided congestive heart failure and failure to identify another cause of signs of respiratory disease should increase suspicion for PVOD and PCH. With increased awareness of PVOD and PCH by clinicians and pathologists, dogs with compatible clinicopathologic features should be evaluated for these pulmonary vascular disorders.

ACVIM consensus statement guidelines for the diagnosis, classification, treatment, and monitoring of pulmonary hypertension in dogs

“…D6. If not already performed, echocardiography to assess the probability of PH should be considered when thoracic CT angiography shows ≥1 of the following: A pulmonary trunk‐to‐descending aorta ratio ≥1.4 Evidence of RA and RV enlargement A decreased pulmonary vein‐to‐PA ratio; an increased pulmonary trunk‐to‐ascending aorta ratio, or an increased RV‐to‐LV ratio The presence of pulmonary arterial filling defects A mosaic attenuation pattern showing small vessels in a region of decreased attenuation (ie, hypoperfusion) on an inspiratory scan that fails to show accentuation of the mosaic attenuation pattern on an expiratory scan (ie, ruling out air trapping) Perivascular diffuse nodular to ill‐defined patchy ground‐glass opacity with a global distribution, compatible with pulmonary capillary hemangiomatosis (PCH) or pulmonary veno‐occlusive disease (PVOD) Consensus in 7/7 members of the panel and 5/5 advisory reviewers Comments: Although measurement of RV (and perhaps RA) enlargement evaluated on contrast CT scan is suspected to be a viable metric for PH, peer‐reviewed studies in dogs with PH have not yet been published. Additionally, signalment and physical examination should be used to discriminate dogs with pulmonary valve stenosis that also may have findings a‐c above . …”

“…Using PDE5i in dogs with group 1’ disorders may result in fatal acute pulmonary edema as seen in some humans; this may occur because higher blood flows are not accommodated by the fixed downstream obstruction in the veins, capillaries, or both. Although insufficient evidence of a similar phenomenon exists in the veterinary medical literature, the recommendation is that PDE5i be initiated in the hospital in dogs with known or suspected PVOD and PCH, with close monitoring for development of acute pulmonary edema. The drug should be withdrawn immediately if this complication occurs.…”

“…Most of the peer-reviewed veterinary medical literature regarding dogs with PH has evaluated the PDE5i, sildenafil. 40,42,43,52,80,84,[205][206][207] These studies suggest benefit with improvement of clinical signs, 52 quality of life, 52,84,207 exercise capacity, 84 Treatment strategies for PH are highly dependent on cause and chronicity of PH. Some PH-specific treatments (eg, pulmonary artery vasodilators such as PDE5i) might lead to acute pulmonary edema in some dogs with PH.…”

“…D1. Echocardiography to assess the probability of PH should be considered as an early diagnostic test in dogs with clinical findings suggestive of PH (Table ) after physical examination and thoracic imaging rule out another specific disorder not associated with PH. Consensus in 7/7 members of the panel and 5/5 advisory reviewers …”

“…6.1.1 | Consensus recommendations for PH diagnosis D1. Echocardiography to assess the probability of PH should be considered as an early diagnostic test in dogs with clinical findings suggestive of PH(Table 1)35,36,51,80,99,109,162 after physical examination and thoracic imaging rule out another specific disorder not associated with PH.…”