PV atresia

Question 1

PA atresia def

Answer 1

Imperforated pulmonary valve obstructing the flow to pulmonary circulation

Question 2

Types of PA atresia

Answer 2

Intact IVS
Concurrent VSD

Question 3

PA w/ intact IVS: features

Answer 3

o Usually normal atrial, AV and arterial connections
o 3 fused, well formed leaflets
o Valvular atresia in 75% of cases, muscular in 25%

Question 4

PA w/ intact IVS: pathophys

Answer 4

 Restrictive ASD is the only exit from RA
 PDA must be present to provide pulmonary blood flow

Question 5

PA w/ intact IVS: mx intervention

Answer 5

 Maintain DA patency: prostaglandins

Question 6

PA w/ intact IVS: sx intervention

Answer 6

 Early correction
* Balloon valvuloplasty
* Ductal stent placement in PDA
* Balloon atrial septostomy to open FO
* Systemic to pulmonary artery shunt (Blalock)
 Later procedures
* Biventricular repair ideally
* Bidirectionnal Glenn procedure (CrVC → PA)
* Fontan procedure

Question 7

PA atresia w/ VSD

Answer 7

o Most severe form of Tetralogy of Fallot

Question 8

PA atresia w/ VSD: mx management

Answer 8

phlebotomy

Question 9

PA atresia w/ VSD: sx management

Answer 9

 Palliative: if PA anatomy precludes repair
* Systemic to PA shunt → ↑ pulmonary flow
 Complete repair: PA size at least >50% its normal size
* RVOT reconstruction → connect RV to PA using conduit
* Closure of septal defects

Question 10

Embryology

Answer 10

• Abnormal connection btwn heart and PA
  o After cardiac septation → intact IVS
  o Blood supply to lungs = variable blood flow via
   DA
   Bronchial arteries
   Systemic → pulmonary collaterals
• Pseudotruncus arteriosus
• Extreme form of TOF
  o Severe deviation of muscular septum toward RVFW
  o Ao receives all of primitive OT
  o Atretic PA

Question 11

Gross exam PA atresia intact IVS

Answer 11

most severe form of PS
o Imperforated PV → complete obstruction of forward flow
o +/- RVOTO: membranous/muscular atresia
o Obligatory R → L shunt via PFO or ASD
o Varying degree of TV/RV hypoplasia

Question 12

Gross exam PA atresia w/ VSD

Answer 12

• VSD: common
  o Most severe form of TOF
  o Severe deviation of muscular septum toward RVFW
  o Ao receives all of primitive OT
  o Well developed collaterals supply parenchyma

Question 13

Pathophys PA atresia

Answer 13

• Lesion is ductal dependent → pulmonary circulation depend on PDA or bronchial circulation
  o ASD maintain flow to L
• Systemic venous blood → RA → ASD → LA → LV → Ao → PDA → PA

Question 14

C/s PA atresia

Answer 14

cyanosis develop early in life

Question 15

CTX PA atresia

Answer 15

• Enlarged ascending Ao: bulge of cranial border on lateral view
• ↓ pulmonary vascular markings

Question 16

Echo Pa atresia

Answer 16

difficult to impossible to visualize the atretic PA
* Can highlight presence of PDA

Question 17

Unilateral atresia/hypoplasia of the pulmonary artery

Answer 17

• Unilateral absence of a PA
  o One branch of PA is absent: involution of proximal 6th Ao arch on either side during embryogenesis
  o Most commonly RPA in Hu
  o Distal PAs on the side of lesions supplied by DA
  o Development of systemic to pulmonary collateral vessels is common
• Reported in 3 cats: 6mo, 2y, 4y
  o Hu: most are asymptomatic until adulthood

Question 18

Unilateral atresia/hypoplasia of the pulmonary artery c/s and PE

Answer 18

• C/s: exercise intolerance, tachypnea
• PE: nonspecific systolic murmurs

Question 19

Unilateral atresia/hypoplasia of the pulmonary artery CTX

Answer 19

• ↓ lung volume on affected side
• Hyperperfusion of contralateral lung
  o Interstitial opacity
• Mediastinal shift
• Asymmetry in PA branch size

Question 20

Unilateral atresia/hypoplasia of the pulmonary artery echo

Answer 20

• Signs of PH: RVE/RAE, ↑TR
• Suggest absence of one PA branch