- Hacking, coughing, vomited once; progressive dyspnea.
- Recently fainted after coughing.
- Grade V/VI systolic heart murmur bilaterally.
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- Moderate right-sided cardiomegaly characterized by a rounded ranial/right border of the heart, with increased sternal contact
- “Reverse-D” ad “3/5 – 2/5 cardiac ratio”
- Caudal pulmonary enlargement.
- Patchy intersitial lung pattern, worst caudodorsally.
- Predominately right-sided cardiogemaly with patchy intersitial lung pattern. Considerations are given to non-cardiogenic pulmonary edema secondary to pulmonary hypertension. Cardiogenic pulmonary edema secondary to mitral/tricuspid insufficiency, interstitial pneumonia and neoplasia can also be considered.
- Echocardiogram showed severe pulmonary hypertension (high gradient; tricuspid regurgitation, minimal mitral regurgitation; no left-sided enlargement.
- Responded well to Sildenafil.
- Classic presentations
- Small breed dogs with concurrent myxomatous valve (mitral and tricuspid) and history of congestive heart failure.
- Terrier-type dogs with chronic history (pulmonary fibrosis).
- Young dog or rescue dogs from the south (heartworm disease).
- No-so-classic presentations
- Small breed dog with no left atrial enlargement, no prior history of congestive heart murmur, +/- murmur, no chronic airway disease in the history (including no prior abnormal lung pattern), and heartworm negative.
- Collapse episode may be described as a seizure or wobbliness.
- Collapse episode tends to happen after excitement or exercise.
Sildenafil-responsive non-cardiogenic pulmonary edema
- Results from pulmonary hypertension where there are regions of high pulmonary blood flow (no vasoconstriction) and low pulmonary blood flow (vasoconstriction).
- The high flow areas experience higher hydrostatic pressure.
- The capillary beds of the high flow areas become more permeable leading to edema with high proetin and RBCs.
- Sildenafil reduces “perfusion heterogeneity”.
- Pulmonary infiltrates are often “patchy”.
- Misdiagnosis as cardiogenic pulmonary edema or pneumonia is common.
- Fails to respond to lasix/enalapril alone.
- Sildenafil is safe and can improve the lung pattern shortly after administration.
- Adams DS, Marolf AJ, Valdés- Marnnez A, Randall EK, Bachand AM. Associations between thoracic radiographic changes and severity of pulmonary arterial hypertension diagnosed in 60 dogs via Doppler echocardio-graphy: a retrospective study. Vet Radiol Ultrasound. 2017;58:454–462.
- Kellihan HB, Waller KR, Pinkos A, et al. Acute resolution of pulmonary alveolar infiltrates in 10 dogs with pulmonary hypertension treated with Sildenafil citrate: 2005-14. J Vet Cardiology (2015).