Page 316 - Clinical Small Animal Internal Medicine

284 Section 3 Cardiovascular Disease

when indicated. The fluid in the red‐top tube should be results. Balloon pericardiotomy has been described as a
VetBooks.ir monitored for clotting, which could indicate inappropri- palliative procedure for neoplastic effusions.
ate intracardiac placement of the catheter. Pericardial
fluid does not routinely clot. A packed cell volume
(PCV) on the effusion can be obtained to confirm that Prognosis
the fluid is not blood. Prognosis depends on the underlying cause of the effu-
7) Once pericardial effusion is no longer withdrawn, sion. Pericardiectomy can result in clinical improvement
ultrasound can be used to confirm the pericardial or cure in idiopathic cases and in infectious cases when
effusion has been removed or has drained into the combined with appropriate antibiotic or antifungal ther-
thoracic cavity. Pleural effusion can be removed prior apy. Pericardiectomy extends survival time in dogs with
to withdrawing the catheter from the thorax. heart base tumors and is associated with minimal
improvement with hemangiosarcoma and mesotheli-
Monitoring and Follow‐Up oma. In cats, prognosis with effusion secondary to heart
Pericardiocentesis often results in immediate clinical disease and heart failure is guarded to poor due to the
improvement. Careful monitoring of the patient for fur- presence of severe underlying heart disease.
ther hemodynamic collapse or clinical improvement is
recommended following the procedure. Ideally, dogs
should not be sent home immediately after pericardiocen- Constrictive Pericarditis
tesis and are monitored in the hospital for 12–24 hours.
Rapid (minutes to hours) reaccumulation of pericardial Etiology/Pathophysiology
fluid and significant arrhythmias are possible following
pericardiocentesis. If pericardiectomy is not scheduled Constrictive pericarditis is characterized by a stiff,
(see Surgical Management for recommendations), recheck fibrous pericardium that impairs ventricular diastolic
within 2–4 weeks and consider pericardiectomy if the filling even if no fluid is present. Although considered
pericardial effusion has reaccumulated. uncommon, the diagnosis is difficult to make and can
be overlooked. It is characterized by an absence of peri-
cardial effusion though combined constrictive‐effusive
Cancer Therapy disease does occur. Chronic pericardial and pleural

Palliative or definitive cancer therapy rarely is successful effusion including chylous effusion and infectious peri-
with cardiac neoplasia. Complete surgical excision can carditis secondary to fungal organisms can result in
rarely be achieved because of tumor proximity to vital constrictive pericarditis.
structures. There are reports of a positive response to
chemotherapy for lymphoma and hemangiosarcoma. Signalment
Consultation with an oncologist is recommended for the Similar to pericardial effusion.
most current therapeutic strategies.
History and Clinical Signs
Surgical Management
Similar to pericardial effusion with a high incidence of
Despite fluid removal and immediate clinical improve- signs of elevated right heart pressures.
ment, pericardial effusion is likely to recur in most
instances. Surgical pericardiectomy (partial or subtotal) Diagnosis
allows improved visualization for the surgeon to iden-
tify the underlying etiology and/or biopsy a tumor. Echocardiography
Echocardiography is very specific for identifying a tumor Pericardial effusion is often absent or small volume.
but not 100% sensitive, particularly for small tumors that Tamponade may be documented with only a small vol-
may be readily identified by a surgeon. A small pericar- ume of effusion. The pericardium can appear thickened.
dial window provides palliation but can potentially lead Advanced Doppler studies show respiratory changes in
to constrictive pericarditis of the remaining pericardium the peak velocities of mitral and tricuspid valve inflow
or allow herniation of a portion of the heart through the profiles highly suggestive of constrictive physiology.
pericardial opening. Pericardiectomy can be curative for
idiopathic and infectious etiologies and extend survival Cardiac Catheterization
for dogs with chemodectomas. Thoracoscopic pericar- Characteristic patterns in atrial and ventricular pressure
diectomy has the benefit of offering lower patient mor- profiles are indicative of constrictive physiology although
bidity but requires a skilled operator to achieve optimum administering a fluid bolus may be required to generate