Cardiovascular Pathology Labpeople.upei.ca/smartinson/Cardiovascular_lab_1-17.pdfSignalment: •10 year old MC DSH Cat History • Heart murmur detected on PE – recommended cardiac

Cardiovascular Pathology Lab

Shannon Martinson, 2017 http://people.upei.ca/smartinson/

Signalment: • 10 year old MC DSH Cat History • Heart murmur detected on PE – recommended cardiac US • Blood work was done to check for hyperthyroidism - T4 levels were normal • Sudden right facial paralysis and loss of sensation of the right side of the face • Cat was euthanized

Case 1

Case 1

“Normal” cat heart for comparison

• The heart is markedly enlarged with thickening of LV free wall, the IVS, and the RV wall.

• The LV chamber in particular is reduced in size

• The atria are dilated – especially the LA which contains a large brown and tan thrombus that occludes the lumen

Description

Case 1

• Left ventricular hypertrophy, concentric, marked

• Right ventricular hypertrophy, mild to moderate

• Left atrial thrombus, occlusive

Morph Diagnosis

Usually pressure overload: • Subaortic stenosis • Systemic hypertension • Idiopathic / genetic

• Hypertrophic cardiomyopathy • Hyperthyroidism

What are possible causes for the changes in the left ventricle?

Case 1 What disease process do you think this represents?

• Hypertrophic cardiomyopathy

Why do cats with this disease develop atrial thrombosis?

• LA dilation alters laminar blood flow – predisposes to thrombosis

What is another common site for thrombosis in cats with this disease and what clinical signs might be seen as a result?

• Caudal abdominal aorta • Hind end pain /paresis • Cold extremities (hind legs) • Lack of femoral pulses

Possible embolism to the brain (stroke) from the aortic thrombus

Cause of facial paralysis:

Case 2

Signalment: • 1.5 year old intact F

Newfoundland Dog Clinical History: • Murmur detected at a young

age • Recurrent fever and previous

bouts of joint pain • Mild elevation in BUN and

Creatinine • Became anorexic and was

euthanized • Fluid in the chest and red,

heavy lungs seen at necropsy

Case 2

• There is LV hypertrophy and LA dilation

• A band of fibrous connective tissue encircles and narrows the LV outflow tract beneath the aortic valve

• The aorta is dilated above the valve

• The aortic valve is roughened and focally ruptured with a necrotic tract dissecting through to the right atrium

• The chordae and leaflets of the mitral valve are short and thick and attach from the papillary muscle to the ventricular free wall in the area of stenosis

Description

Case 2

• Subaortic stenosis, severe with poststenotic dilation

• Left ventricular hypertrophy, moderate to marked

• Valvular endocarditis, rupture, and tract formation

• Mitral valve dysplasia

Morphologic Diagnosis

Case 2

• Subaortic stenosis→ narrowing of the orifice causes pressure overload of the LV → LV concentric hypertrophy → Left heart failure → Pulmonary edema and congestion

• Increased turbulence above the valve can lead to dilation of the aorta

• The necrotic tract may have occurred as a result of high pressure and weakening of the wall at this site

Describe the hemodynamic alterations resulting from the primary lesion and relate them back to the other findings?

Case 2

• While subtle, there is endocarditis • Malformed valves are predisposed to the

development of endocarditis • The source of bacteria is often

undetermined → presumed bacteremia • Fever may occur during periods of

bacteremia or showering → anorexia • Small thromboemboli, which may be septic,

can be released causing ischemia/infection in the organs • Renal infarcts in this case may have

caused ↑urea and creatinine • Possible ischemic injury in the limbs or

septic showering of the joints may cause lameness

Can you relate the lesions back to the clinical findings / history?

Case 3

Signalment: • Aged male mixed breed dog Clinical History: • 10 day history of lethargy • Using imaging, fluid was detected in the abdomen and thorax: thoraco- and abdomino-

centesis → transudate • A 3rd degree heart block was detected (ECG) – the owners opted for euthanasia

Case 3

• A large (~8 x 4 x 5 cm) irregular solid tan and black mass infiltrates the RA obliterating the lumen and extending into the RV and IVS. The mass encompassed the aorta at the heart base.

• Both ventricles are dilated

• Multiple small (<0.5 cm) red nodular masses are present randomly within the lung.

Description

Histology!

• Hemangiosarcoma • Rhabdomyosarcoma • Chemodectoma

• Aortic body tumour • Carotid body tumour

• Ectopic thyroid carcinoma • Lymphoma

Case 3

• Malignant Neoplasia

What time of disease process is this?

What are some differentials for this lesion?

How would you reach a final diagnosis ?

Case 3

• Hemangiosarcoma, right atrium and lung

Morph Diagnosis

Case 3

Can you relate this lesion back to the clinical signs and other postmortem findings?

• RA mass could have prevented conduction of electrical activity via the AV node to the ventricles → 3rd degree heart block

• The presence of this mass resulted in congestive RHF (impedance of venous flow from the vena cava)→ ascites and hydrothorax

• Arrhythmia and CHF → lethargy • Metastasis to the lung from the primary mass

• Hemangiosarcoma, right atrium and lung

Morph Diagnosis

http://img.tfd.com/MosbyMD/conduction-system-of-the-heart.jpg

Case 3 What is a more common

outcome for these tumours?

• RA rupture → hemopericardium → cardiac tamponade

PBVD, Saunders, 2017

Case 4

Signalment: • 31 day old ram lamb. Clinical History: • Lamb was sick for 10 days and seemed to respond briefly to antibiotic treatment • Became sick again a week later with no response to antibiotics. • The lamb is now in poor body condition – the owner opted to euthanize

Case 4

Case 4

• The pericardial sac is markedly dilated (~ 15 cm diameter) and thickened by dense fibrous connective tissue with a thick covering layer of slightly friable tan shaggy material

• Similar changes are present in the epicardium

• Both the LV and RV are hyertrophied

• Fibrous adhesions span between the pericardium and pleura and there is mild CV consolidation of the lung

Description

• Organizing fibrinous pericarditis, diffuse, chronic, severe

• Biventricular hypertrophy

• Bronchopneumonia and fibrous adhesions

Morph Diagnosis

Case 4 Possible etiology?

• Bacterial infection (sepsis) • Trueperella pyogenes • Pasteurella multocida • Staphylococcus aureus • E coli

What would the most likely underlying disease process be if this was a cow?

• Traumatic reticuloperitonitis (rare in lambs)

Why is there LV and RV hypertrophy?

• Fibrosis of the epicardium and adhesion to the pericardial sac can limit diastolic expansion and cardiac output (= constrictive pericarditis)

Submit a swab for bacteriology • Antibiotic treatment may

hamper microbial growth

Case 5

Signalment: • 21 year old horse Clinical History: • Donated to AVC • Poor dentition and weight loss • Recurrent bouts of colic

Case 5

• The cranial mesenteric artery has a markedly thickened and firm (fibrotic) wall

• The lumen varies in caliber with areas of dilation and narrowing

• The intima is roughed and corrugated with brown to orange discolouration

Description

• Arteritis, proliferative, segmental, chronic, severe, with dilation (aneurysm) and fibrosis

Morph Diagnosis

• Strongylus vulgaris (L4) migration

Etiology

Case 5

• The cranial mesenteric artery has a markedly thickened and firm (fibrotic) wall

• The lumen varies in caliber with areas of dilation and narrowing

• The intima is roughed and corrugated with brown to orange discolouration

Description

• Arteritis, proliferative, segmental, chronic, severe, with dilation (aneurysm) and fibrosis

Morph Diagnosis

• Strongylus vulgaris (L4) migration

Etiology

Case 5

Can you relate this lesion to that seen in the small intestine?

• Arteritis and the resulting endothelial damage promote the formation of a thrombus at the affected site (also altered blood flow in an aneurysm) → pieces can break off as thromboemboli which lodge downstream → in this case an embolus has lodged in a mesenteric vessel

How might this result in colic?

• Thrombosis can result in infarction of the intestine (collateral circulation makes this less likely)

Case 6

Signalment: • 7 week old Holstein bull calf Clinical History : • Calf was ill-thrift, lethargic and had bluish mucous membranes • Found dead one morning

Case 6

Case 6

Case 6

• The heart is enlarged and somewhat globose in shape

• A thick muscular band narrows the right ventricular outflow tract

• The leaflets of the pulmonic valve are white-tan, thick and rugous with partial fusion of the leaflets leaving a central irregular perforation measuring ~ 0.75 cm

• There is moderate to marked RV hypertrophy and the LV ventricle appears dilated

• A 3 cm diameter opening is present high within the IVS and the aorta overrides this opening

• The ductus arteriosis is patent with a 1 cm diameter lumen

• The foramen ovale is covered by a perforated valve (probe patent)

Description

Case 6

• Pulmonic Stenosis

• Ventricular septal defect

• Right and left ventricular hypertrophy

• Over-riding aorta

• Patent ductus arteriosis

• Patent foramen ovale (~ASD)

Morphologic Diagnoses

Case 6 Which of the identified changes would be found in tetralogy of Fallot?

• Pulmonic stenosis • Ventricular septal defect • Over-riding aorta • Right ventricular hypertrophy

Which of these are congenital and which are acquired?

Congenital

Acquired

• Pulmonic stenosis • Ventricular septal defect • Over-riding aorta • Right ventricular hypertrophy

• Patent foramen ovale OR • Patent Ductus Arteriosis

Pentology of Fallot

Pulmonic stenosis

RV pressure overload

R to L shunt through VSD

Cyanosis

RV hypertrophy Right heart

failure

Shunt through the ASD and

PDA?

Case 6 What are the hemodynamic alterations in this case?

PDA and ASD are not though to contribute much to clinical disease when present along with tetralogy