Chapter 107 Pericardial Surgery

Question 1

What are the two layers of the pericardium called?

Answer 1

Outer fibrous, inner serous (serous layer forms parietal and visceral layer (visceral layer = epicardium)

Question 2

What is the name of the ventral attachment of the pericardium to the muscular insertion of the diaphragm?

Answer 2

Sternopericardiac ligament

Question 3

What is normal intrapericardial pressure?

Answer 3

Zero (or negative)

Question 4

What is normal pericardial volume?

Answer 4

1 - 15ml

Question 5

Briefly outline the pathophysiology in increased central venous and portal pressure in cases of tamponade

Answer 5

• Tamponade –> reduced cardiac output and increased systemic venous pressure.
• RAAS activated –> Sodium and water retention
• Sympathetic stimulation –> positive inotropic and chonotropic effects + vasoconstriction.
• Right atrium not stretched therefore no ANP to counteract

Increased systemic venous and portal pressures.

Question 6

Explain the pathophysiology behind pulsus paradoxus

How great is variation typically?

Answer 6

• Increased venous return to R side during inspiration (pericardial and RV pressures decrease) –> pulmonary blood flow.
• However total heart volume limited by pericardial effusion so as Rv fills, septum shifts to left –> reduced L end-diastolic volume and output i.e. decreased arterial pressure.

>10mmHg variation typically.

Question 7

What is the usual histological diagnosis for pericardial cysts?

Answer 7

cystic haematoma

?assoc with PPDH

Question 8

What is the usual clinical presentation of pericardial rupture?

Answer 8

Asymptomatic initially but may stricture –> vanae cavae compression

Question 9

What radiographic findings may be associated with strictured pericardial rupture

Answer 9

Caudal vena cava may appear kinked cranial to diaphragm

Angiogram of a dog with pericardial rupture. The caudal vena cava is kinked (white arrow) between the diaphragm and the right atrium. The pericardium is compressing the caudal vena cava (black arrow).

Question 10

How is strictured pricardium following rupture best diagnosed?

How is it treated?

Answer 10

Caval angiography

R 5th or 6th ICT + cut fibrous band (+- patch angioplasty of cava if cava wall is strictured).

Question 11

List 4 broad differentials for transudative pericardial effusion

Answer 11

• CHF
• PPDH
• Hypoalbuminaemia
• Increased vascular permeability

Question 12

How are exudative pericardial effusions classified?

Answer 12

Infectious vs non-infectious pericarditis

e.g.

Infectious

• FIP
• Fungal/viral

Non-infectious

• Feline cardiomyopathy

Question 13

List 5 differentials for haemorrhagic pericardial effusion

Answer 13

• Idiopathic
• Neoplasia
• L atrial rupture (secondary to MMVD - suspect if pericardial effusion and left apical systolic murmur))
• Coagulation abnormalities
• Trauma

Question 14

What is the most common cause of haemorrhagic pericardial effusion?

Answer 14

Idiopathic

Question 15

What is the most and second most common tumour causing haemorrhagic pericardial effusion?

Answer 15

1. Haemangiosarcoma
2. Chemodectoma

Question 16

What is this ECG trace example of?

Answer 16

Electrical alternans

Due to swinging of beatin gheart within pericardial sac.

Question 17

What is the sens/spec of echo for detection of cardiac masses in dogs with pericardial effusion?

Answer 17

82% sensitivity, 100% specificity

Question 18

Aside from echo, what other test was 100% specific (and 82% sensitive) for detection of cardiac haemagiosarcomas?

Answer 18

[cardiac troponin 1] > 0.25 ng/ml

Question 19

What is the difference between total and subtotal pericardiectomy?

Answer 19

Total = whole pericardium (phrenic nerves peeled off).

Sub-total = ventral to phrenic nerves.

Question 20

List 3 approaches for subtotal pericardiectomy

Answer 20

• MS
• R ICT
• transabdominal, transdiaphragmatic
• (thoracoscopic –> pericardial window)

Question 21

What is the rough size recommendation for pericardial window in large dog (to prevent herniation)

Answer 21

3x3cm

Question 22

What was the MST of dogs with aortic body tumours (?with pericardial effusion) without vs with pericardiectomy?

Answer 22

42d vs 730d

Question 23

List a ‘non-surgical’ technique for creating pericardial window

Answer 23

Percutaneous balloon pericardiotomy

Question 24

What is the MST from onset of pericardial effusion in dogs with mesothelioma?

Answer 24

1 year

Question 25

What combination of findings are suggestive of restrictive pericarditis?

How is it definitively diagnosed?

How is it treated?

Answer 25

Suggestive signs:

• R CHF
• Minimal to no pericardial effusion
• Structurally normal heart and cava

Diagnosis:

• Cardiac catheterisation + measurement of pressures in all chambers + pulmonary capillary wedge.
• Findings
  
  • Equilibration of all chamber pressures
  • M or W shaped atrial pressure trace
  • Square root sign ventricular pressure

Treatment:

• If parietal pericardium involved = pericardiectomy.
• If visceral pericardium (i.e epicardium) involved = decortication (risky in case of coronary artery laceration)