Pericardial surgery Flashcards
What are the layers of the pericardium?
Outer fibrous pericardium, inner serous pericardium (parietal and visceral [epicardium])
What is the name of the ligament that anchors the fibrous pericardium to the muscular insertion of the diaphragm?
Sternopericardiac ligament
What is the blood supply to the pericardium?
Paired pericardial branches of the internal thoracic arteries
What are the functions of the pericardium?
Maintains the heart in its normal anatomic position, restrains cardiac filling and enhances diastolic ventricular coupling, protects against atrial rupture, prevents the spread of infection or neoplasia from the pleural space to the heart.
How much fluid accumulation in the pericardium results in an increase in pericardial pressure?
5 - 60ml
What physiologic changes are associated with cardiac tamponade?
Increases in systemic venous and portal pressures, causing jugular vein distension, liver congestion, ascites, and peripheral edema.
Compression of the coronary arteries may result in poor myocardial perfusion.
What is pulsus paradoxus?
A decrease in systolic blood pressure during inspiration (often greater than 10 mmHg).
Inspiration causes a reduction in pericardial pressure and right ventricular pressure, facilitating venous return to the right atrium and ventricle. Increased venous return causes a leftward intraventricular septum shift and a consequent reduction in left ventricular end-diastolic volume, left heart output and arterial pressure.
What is the suspected cause of pericardial cysts?
Entrapment of omentum, falciform ligament, or liver in the pericardium during development.
Typically in dogs <3 years of age.
What are clinical signs associated with pericardial cyst formation?
Signs range from no signs to cardiac tamponade.
Diagnosis is based off echocardiography.
What is the surgical treatment for pericardial cyst?
Median sternotomy, subtotal pericardiectomy and repair of PPDH if needed. Prognosis is good.
What can ruptured pericardium cause?
May result in no clinical signs, however if the pericardium constricts around the herniated heart may result in Budd-Chiari syndrome (with ascites and hepatomegaly), caval syndrome, or both.
Patients often present with marked ascites.
What is the most valuable technique for diagnosis of pericardial rupture with secondary obstruction of the vena cavae?
Caval angiography
What is the treatment for pericardial rupture and secondary obstruction of the vena cavae?
Right sided 5th or 6th intercostal thoracotomy, release of the fibrotic pericardial sac, resection of the fibrous band crossing the vena cava +/- angioplasty with an inlay pericardial patch graft.
What are some types of pericardial effusion that may be detected?
1) Transudate: CHF, PPDH, low albumin, increased vascular permeability.
2) Infectious.
3) Hemorrhagic: neoplasia, trauma, anticoagulant intoxication, rupture of the left atrium.
4) Idiopathic.
What is the most common cause of hemorrhagic pericardial effusion?
Idiopathic. Neoplasia is second most common (hemangiosarcoma, chemodectoma, pericardial mesothelioma)
What is the typical signalment for a patient with pericardial effusion?
Older large breed dogs, Golden retrievers over-represented.
What are some clinical signs associated with pericardial effusion?
Muffled heart sounds, weak femoral pulses, tachycardia, distension of the jugular and peripheral veins, CVP >10-12 mmHg.
What ECG related change is strongly suggestive of pericardial effusion?
Electrical alternans
Is pericardial fluid cytology typically useful for diagnosis of the underlying cause?
No - diagnostic utility in one study was 7.7%. Majority of effusions are sanguineous or serosanguineous.
List 5 diagnostics that might be considered in the work-up of pericardial effusion.
- Pericardial fluid cytology and analysis.
- ECG
- Thoracic radiography
- Echocardiography
- Plasma cardiac troponin 1 concentrations (concentrations >0.25 ng/ml 82% sensitive and 100% specific for cardiac hemangiosarcoma).
Where are chemodectomas most frequently localized on echocardiography?
Along the ascending aorta.
Right atrial masses are most likely to be hemangiosarcomas, and myocardial infiltrates in the cat are most likely lymphoma.
What are treatment options for pericardial effusion?
1) Pericardiocentesis: 5th/6th right intercostal spaces (to avoid the major coronary arteries). Fluid should be submitted for cytology, biochemical analysis and culture.
2) Pericardiectomy: can be curative for idiopathic effusion and palliative for neoplastic effusion.
What are potential complications associated with pericardiocentesis?
Occur in <10% of cases, include dysrhythmias, cardiopulmonary arrest, or continued bleeding.
What are the types of pericardiectomy?
1) Complete: removal of all the pericardium. Performed via median sternotomy.
2) Subtotal: ventral to the phrenic nerves. Can be performed via sternotomy, right lateral thoracotomy, transabdominal/transdiaphragmatic incision, thoracoscopic (transdiaphragmatic).
3) Pericardial window: thoracoscopic (lateral or transdiaphragmatic approach).
