PS Flashcards
Patterson et al. typical valvular lesions
- Fused valve leaflets w/o thickening
- Dome-shaped valve with central orifice
Patterson et al. grade 1 PV dysplasia lesions
- Less common → marked thickening of valve leaflets w/o fusion
o Grade 1: slight thickening of valve leaflets
Little/no fusion or hypoplasia
Minimal or no pulmonary outflow obstruction
Patterson et al. grade 2 PV dysplasia lesions
o Grade 2: moderate to severe thickening of valve leaflets
With fusion or hypoplasia or both
Moderate to severe pulmonary outflow obstruction
Patterson et al. valvular pathology
- PV annulus normal or slightly ↓ size
- Thickening
o Some degree of thickening in all affected dogs
Slight thickening
Bulky, non-flexible, cushion-like leaflets filling valve orifice
o Equal involvement frequency among 3 leaflets
o Small irregular nodules on leaflets surface - Hypoplasia
o Smaller size leaflet vs normal dog
o Variable degree from slight reduction to complete absence
Often mishapen
o Usually 1 or 2 leaflet involved, most often L involved > anterior > R - Fusion
o Adjacent leaflets do not insert separately on intimal surface of PA
o Variable degree from slight (<1/4) to complete fusion
o 3 commissures affected w equal frequency
Histo of normal PV
o Fibrosa layer on arterial side
Covered by layer of flat endothelial cells
May contain elastic fibrils
Not completely separated from spongiosa
o Spongiosa layer
Variable thickness
Loose fibrillar material, fragments of collagen and widely separated cells
o Ventricularis layer on ventricular side
Fibroelastic layer
Covered by layer of flat endothelial cells
Histo lesions PS
- PS: thickening of spongiosa w loosely arranged collagen tissue
o Similar cell population
Embryology DORV
- Etiology: uncertain
o Localized growth of trabeculated myocardium early in development
o RV subdivision/obstruction from arrested incorporation of primitive bulbus cordis into RV body
Incomplete fusion of bulbar or endocardial cushions → associated VSD
gross exam DORV
- Obstructive fibrous band
o Jct of RV body and proximal infundibulum
o Below crista supraventricularis - Anomalous muscle bundles traversing middle of RV: supraventricular crest → RV apex
o Proximal hypertrophied chamber → sinus portion of RV
o Distal low pressure chamber → infundibulum portion - Pyramidal mass of muscle below TV from IVS → RVFW
o 2 bundles
Ventral bundle: attach RVFW → IVS
Dorsal bundle: larger, attach to base of anterior pap muscle
o Near the base of TV ring (vs moderator band is usually more apical, no obstruction)
Types of DORV
o Type I: fibromuscular band of tissue at jct of RV cavity and pulmonary infundibulum (proximal RVOT)
o Type II: fibromuscular thickening of pulmonary infundibulum → just below PV
Signalment DORV
asymptomatic animal with heart murmur
o Can also present in R sided CHF
PE DORV
loud pansystolic crescendo-decrescendo murmur
ECG DORV
- ↑ QRS duration
- R axis deviation
- Junctional tachycardia
- APC/VPCs
CTX DORV
- Cardiomegaly, R sided
- Cardiac silhouette can also be normal
2D echo DORV
o RVH
o RAE
o Anomalous muscle bundles: muscle proliferation causing obstruction of flow
o Abnormal fluttering of PV
Doppler echo DORV
o PG across mid RV: obstruction is proximal to infundibulum
Vs TOF: obstruction at infundibulum
Degree of obstruction can vary
o VSD
Cardiac KT angio DORV
o Filling defects w/I RV below crista supraventricularis
o VSD
Cardiac KT pressure stury DORV
o ↑ pressure in proximal/sinus portion of RV vs lower cavity
o Pressure in distal chamber = PAP
Unless concommittant PS
Natural hx and tx DORV
- Severity increase in time
- Treatment: balloon valvuloplasty, surgical division
PS embryology
- Valve development: 3 endocardial swellings → excavation forms cusps
Gross exam grading system PS
o Grade 1:
Slight thickening of PV leaflets w little to no fusion/hypoplasia
Minimal to no pulmonary OT obstruction
o Grade 2: dysplastic valve
Moderate/severe thickening of PV leaflets
Fusion, hypoplasia, dome shaped PV leaflets
Moderate/severe PV flow obstruction
Breeds abn CA PS
o English Bulldogs and Boxers
Concurrent defects PS
TVD (large breeds), PFO
Histo PS
- Overproduction of normal valve element: 2nd to failure of conversion of embryonic valve primordia
o Thickening of the valve spongiosa
o Bands of fusiform
o Dense collagen network - Blood filled spaces lined w endothelium found in cusps
Pathophys PS
- ↑ RVOT resistance to blood flow → ↑RV systolic P → RVH
o Proportional to severity of obstruction
o Infundibulum hypertrophy → dynamic RVOTO - Myocardial response to ↑ wall stress
o Neonatal: hyperplasia + ↑# of capillaries
o Adult: hypertrophy of existing fibers - RAE:
o TR
o ↑RV filling P
o ↓ CO → activates RAAS - RVE: RV failure from
o ↓ RV SV
o R-CHF
Signalment PS
o Predisposed breeds: Bulldogs, Beagle, Samoyed, Chihuahua, Miniature Schnauzer, Lab, Mastiff, Chow chow, Newfoundland, Basset Hound, Keeshond, WHWT, Terrier, Spaniels
Genetics: heritable in Keeshonds and Beagles
o Rare in cats
C/s PS
most asymptomatic or
o Signs related to ↓ CO: syncope, lethargy
o R-sided CHF
o Cyanosis if R → L shunting defect
PE PS
o Systolic ejection murmur at L base
+/- systolic apical (TR)
+/- diastolic basilar (PI)
+/- pulmonary ejection click → doming of PV
+/- split S2 → ↑ RV ET
o Jugular pulse
ECG PS
- R axis deviation
- Tall/peaked P waves
- Transient RBBB following BV reported
CTX PS
- MPA dilation
- R sided cardiomegaly
- Pulmonary underperfusion
2D echo PS
o Abnormal PV
Systolic doming
Thickened/fused leaflets w ↓ motion
↑ echogenicity
Type A (Typical)
* Commissural fusion
* Normal PA annulus
* Aortic:pulmonic ratio of <1.2
* Post stenotic dilation
Type B (Dysplastic)
* Dysplastic, immobile leaflets
* Narrow annulus/hypoplastic
* Aortic:pulmonic ratio of >1.2
o Flattening/paradoxical IVS motion
o RVH w prominent pap muscles
o Muscular narrowing of RVOT
o ↑ endocardium echogenicity (fibrosis)
o Post stenotic MPA dilation
Dopper echo PS
o High velocity/turbulent flow across stenosis
o PG across PV: Mild 30-50mmHg, Moderate 50-80mmHg, Severe >80mmHg
o PI: secondary to abnormal valve apparatus and PA annular dilation
Diastolic fluttering of TV
↑ velocity if PH (>2.5m/s)
o TR
Cardiac KT angio PS
o Post stenotic dilation of MPA
o Features of PV dysplasia
Narrowed valve orifice
Asymmetric valve sinuses
Hypoplasia of annulus/valve sinus
Systolic valve doming
Filling defect → from thickening of leaflets
o RVH
o Levophase: look for single RCA
Cardiac KT pressure study PS
o Systolic PG across obstruction
o ↑RV systolic pressure
o ↑RAP: ↑a wave
Natural hx PS
- PV dysplasia most frequent in dogs
o Subvalvular/supravalvular stenosis reported but unfrequent
Supravalvular: Giant Schnauzer
o Pulmonary atresia → most severe form - Mild to moderate PS may live normal lives.
- Moderate: most dogs are ok, uncertain px long term
o PG ↓ might be beneficial if concurrent TVD - Severe may develop c/s and R CHF
o General correlation btw PG and survival
o Progressive muscular hypertrophy can worsen PG w DRVOTO
o Usually balloon valvuloplasty will be attempted to ↓ PG
Single RCA → BV contra indicated, can place stent
Decr px PS
when c/s develop
o Exercise intolerance
o R-CHF
o Arrhythmias (Afib)/sudden death
Tx PS
o BVP: especially if dysplatic valve w/o hypoplasia
o Stent: indicated in CA anomaly of PA hypoplasia
TR: contra indicated since will ↑ RV volume over load w/ creating PI
o Sx
RVOTO can be associated w/
o HCM
o High output states: hyperT4, anemia, fever, pregnancy
RVOTO PE
soft early to mid systolic high frequency murmur
o Murmur can change with HR and body position
Echo DRVOTO
↑ velocity in RVOT
o No other cause of murmur on echo and normal heart
