Additional ports are placed under direct observation at about the seventh and third left intercostal spaces. Endoscopic graspers
are used to pick up pericardium. When a good grasp of the pericardium has been achieved, the pericardium is lifted away from
the heart and endoscopic scissors connected to the cautery unit are used to make the first cut in the pericardium (Photo 2).
Effusion will spill out at this time. Suction can be used to clear the field if needed. The graspers and cutters are used
via the two instrument ports, switching position of the instruments as needed to remove a portion at least 3-cm square from
the ventral pericardium. Every cut is visualized to ensure that the lungs and phrenic nerve are not in danger of trauma. The
camera can be moved to one of the intercostals ports and the paraxiphoid port used for an instrument. This is occasionally
helpful to complete the procedure. Bleeding is usually adequately controlled with the use of cautery through the scissors
as each cut is made (Photo 3). Mediastinal vessels can be a source of hemorrhage. Endoscopic clips can be used if needed to
aid in control of hemorrhage. Conversion to an open procedure is rarely needed for bleeding that cannot be controlled. The
piece of pericardium is removed via the port with the grasper. The port can be withdrawn and the incision enlarged slightly
if needed for retrieval. The pericardium is submitted for histopathology, particularly in the absence of a heart base or right
atrial mass. A red rubber catheter is placed via the paraxiphoid port and kept in place when the ports are removed to allow
evacuation of any fluid and air. The port incisions are closed routinely. The chest is evacuated again at the end of the procedure,
then the red rubber catheter is removed.
Photo 3: Each cut in the pericardium is visualized. The scissors are attached to an electrocautery. The epicardial surface
is visible. The pericardium can be lifted away from the heart.
Postoperative management includes routine monitoring and pain management. Most cases are able to go home the next day. Some
pleural fluid is expected after surgery since the underlying source of effusion has not been removed, but the amount of fluid
in the pleural space is unlikely to cause clinical signs.
The prognosis depends upon the etiology of the pericardial effusion. The prognosis for hemangiosarcoma is poor. Median survival
time with surgical removal of the hemangiosarcoma and chemotherapy has been reported as 175 days, versus 42 days with surgery
alone. Aortic body tumors have a relatively good prognosis following pericardectomy. Growth is often slow with only a 10-percent
to 20-percent metastatic rate. Evidence of metastatic disease does not significantly alter survival time. Aortic body tumors
are reported to have a median survival of 730 days post-pericardectomy versus 42 days without.
The prognosis for IPE is good to excellent. The prognosis for mesothelioma is generally poor. It can be difficult to differentiate
IPE from mesothelioma even with histopathology because there can be exuberant mesothelial proliferation present in cases of
IPE. Mesothelioma can be seen in small-breed dogs, whereas most IPE is seen in large breeds. Survival times of more than 120
days post-pericardectomy is associated with a higher probability of IPE than mesothelioma.
Constrictive pericardial disease is a rare condition in which pericardial fibrosis results in impaired diastolic function.
The clinical signs are of systemic congestion and low cardiac output, and the treatment involves thoracotomy for pericardectomy
and potentially epicardial stripping.
Carl Sammarco, BVSc, MRCVS, Dipl. ACVIM (cardiology) joined Red Bank Veterinary Hospital, Tinton Falls, N.J. in 2001. He previously
served as a lecturer/assistant clinical professor at the University of Pennsylvania, where he completed a residency in cardiology
in 1994 .
Jill Sammarco, BVSc, MRCVS, Diplomate ACVS joined Red Bank Veterinary Hospital in 2003. She completed a residency in surgery
at the University of Pennsylvania in 1995 and is a veterinary graduate of the University of Liverpool in England.