Pulmonary & Systemic Hypertension

What physiologic changes cause PH?

-increased PVR

-increased pulmonary blood flow

-increased pulmonary venous pressure

Clinically significant PH is usually secondary to

Increased PVR

What can cause a sustained increase in PAP that is not due to increased PVR?

-pulmonary arteriolar vasoconstriction

-pulmonary vascular dz (fibrosis)

PE signs of PH

-increased lung sounds and crackles

-R apical systolic murmur

Clinical signs of PH

-syncopy with exertion or activity

-R sided heart failure

How can we get a definitive diagnosis of PH?

Right heart catheterization

What do we realistically do in vet med to get presumptive diagnosis?

Echo!!!

Precapillary PH

-pulmonary arterial hypertension

-due to increased PVR

-R heart changes, L heart normal

Postcapillary PH

-pulmonary venous hypertension

-due to increased pressure in P2

-PVR is normal, right heart normal, LA BIG!

Combined pre and postcapillary PH

Increased PVR and P2!! Caused by chronic severe LHD with PVD from chronic increased P2. Right heart changes, LA big

Clinical classifications of PH

1. PAH (idiopathic — biopsy)

2. LHD

3. Resp dz/hypoxia

4. Precapillary obstruction

5. Parasites

6. Multifactorial

Sildenafil

-PDE-5 inhibitor

-vasodilates PA

When to NOT give sildenafil?

-LHD (increased pulm edema)

-L to R shunt (needs surgery)

What factors determine systemic arterial pressure?

-SVR determined by arteriolar size

-blood volume regulated by kidneys

Gold standard BP measurement

Direct

Who should you not use oscillometric BP in?

Cats

What dz in cats cause hypertension?

-hyperthyroid

-CKD

What dz in dogs causes hypertension?

-CKD and AKI

-Cushings

-diabetes

-pheochromocytoma

Is heart dz a sign of hypertension?

NO

At what level of BP is TOD likely?

>160mmHg

Strong indications for TOD based on kidneys

-glomerulosclerosis

-proteinuria

-azotemia

Strong indications for TOD based on heart

-systolic murmurs/gallop sounds

-looks the same as primary HCM in cats (LV concentric hypertrophy)

-CHF after fluid therapy

Strong indications for TOD based on eye

-retinal changes / detachment

Strong indications for TOD based on brain

-encephalopathy

-edema/arteriosclerosis

-neuro signs

Dog systemic hypertension treatment

Start with RAAS inhibition (benazepril/enalepril) and then can amlodipine if TOD or severe hypertension

Cat systemic hypertension treatment

1st line is going to be amlodipine! RAAS inhibitors are NOT 1st line in cats!

Stepwise approach to measuring hypertension in cats

Flow map systemic hypertension management