Atrial Septal Defects

Atrial Septal Defects

Dr Nithin P G

Preview

• Introduction

• Embryology & Types of ASD

• Physiology, natural history & clinical features

• Investigations -salient features

• Management

References 1. Joseph Perloff. The clinical recognition of congenital heart disease. Fifth

Edition 20032. Abraham M. Rudolf. Congenital diseases of the heart. Third Edition 2009 3. Moss & Adams’ Heart diseases in infants, children & Adolescents.

Seventh Edition 20084. Nadas' Pediatric Cardiology. Second Edition 2006 5. ACC/AHA 2008 Guidelines for the Management of Adults With

Congenital Heart disease6. ESC Guidelines for the management of grown-up congenital heart

disease 2010

Introduction

• 6-10% of all cardiac anomalies(3)

• M:F = 1:2 [ sinus venosus defects 1:1](1)(4)

• 1 in 1500 live births(3)

• Most common congenital abnormality in adult > 40yrs [30-40%]

Embryology & types of ASD

• Embryology [video]

• Types of ASD– Secundum ASD

– Primum ASD

– Sinus venosus ASD

– Coronary Sinus type

– PAPVC

Embryology & types of ASD

Embryology & types of ASD

Associated anomalies(5)

• 30% cases have associated anomalies

– Secundum- Valvular PS, MVP, PAPVC

– Primum- Cleft MV, Discrete subaortic AS

– SV- PAPVC

– Coronary Sinus- PAPVC, PLSVC

Embryology & types of ASD

Inherited disorders- secundum ASD(3)

• Holt-Oram syndrome [AD] – TBX5

• Familial syndromes– NKX2.5 and GATA4– missense mutation in myosin heavy chain 6

Physiology, natural history

Physiology, natural history

Shunt (2)

• Size of defect– As large as mitral valve orifice

• Ventricular compliance [ most important]

Physiology, natural history

Effects of changes in SV of left and right ventricles associated with changes in PVR and with changes in compliance of the respective ventricles after birth in the presence of an ASD(2)

Physiology, natural history

ASD shunt flow during cardiac cycle(3)

Physiology, natural historyEffects of L to R shunt(2)

• RA/RV dilation, volume overload RV, RVF • Atrial arrhythmias

• Increased PBF

• +/- PAH

Physiology, natural history

ASD & PAH• Not all individuals develop PAH

702 pts isolated ASDs [Secundum or SV]. 40 (6%) had PVOD, defined as a TPR of >7 U/m2 ….34 women (85%) and 6 men… < 19 years of age no PVOD. Circulation 1987;76:1037-1042

• Why others are spared?

• Factors– Increased PBF– Coexistant PAH– Concominant adult heart diseases

Physiology, natural history

Clinical course(1) (2) (3) (4) (5)

• Infancy

• Child hood

• Adults

Clinical Findings

• G/E- thin, upper limb abnormalities• JVP- mean normal, a=v• Pulse & BP- no change in pulse volume and BP during valsalva,

square wave response • Prominent RV pulsations, 2nd space pulsations• Auscultation

– Loud T1– Wide fixed split S2– Pulmonary ESM– Tricuspid MDM

• Features of PAH in some cases

Differential diagnosisMitral Stenosis

Dyspnea, orthopnea

AF

RV impulse

Loud T1 vs Loud M1

A2-P2 vs S2-OS

MDM Tricuspid vs MDM mitral

Increased pulmonary vasc.

Mitral Regurgitation

AF

TR murmur vs MR murmur

Wide split S2

MDM Tricuspid vs MDM mitral

S3

Acquired heart diseases

CAD

Atrial arrhythmias

Special situations

• Lutembacher- RHD MS/MR + secundum ASD

• PAPVC & Scimitar syndrome

• Raghib’s syndrome- coronary sinus ASD + PLSVC

PAPVC & Scimitar syndrome(1)

Investigations- salient features ECG• SN dysfunctions

– AF, AFL, SVT– Absence of sinus arrhythmia

• AV conduction – Increased PR interval– CHB

• rsR’ or rSr’ pattern in V1

• Crochetage [notched R II,III,aVF]

Investigations- salient features

CXR

• RAE

• RV Apex

• Prom MPA

• Increased PBF

Investigations- salient features

Echo

– Most important Ix for confirmation of diagnosis, location and type of ASD, severity, need for intervention & planning further Mx/ Follow up

– RA, RV Volume overload

– Associated abnormalities

– Abnormal venous connections

– Suitability for device closure, rims

Investigations- salient features

Bi-caval view for IVC & SVC rims [subcoastal sagittal & TEE]

Investigations- salient features AV rim & Postero-

superior (atrial) rim[Suboastal coronal & TEE 4C]

Aortic rim[TTE PSX & TEE BSX]

Investigations- salient features

• MRI

Investigations- salient features

CATH• Main indication is assessment of PVR in doubtful cases &

anomalous venous connections not visible on echo• Oximetry

– SVC step up 10% or 5% in 2 serial samples [AVSD, RSOV/LV to RA, VSD + TR, PAPVC, Systemic AVF]

– SVC sat >75-80% [RPV to SVC, LPV to L inominate vein]– CS sat > 45% PLSVC or anomalous PV connections to CS

• Pressures– RA, LA mean normal, RA a=v– RVSP 35-40 mm Hg in infants & 25-30 mm Hg in Adults, diff of 15-30

mm b/w RVSP & PAP noted

Management

• In whom, When & How should you close the defect ?

– RV volume overload [+/- symptoms]– Paradoxical embolism

• Surgical vs Device closure

Management(5) (6)

• <5 mm, no volume overload [unless paradoxical embolism] followed up

• Secundum ASD>5 mm, <38 mm size with a rim of 5 mm all around except towards aorta Device closure [Larger ASD, associated tricuspid repair, sinus venosus, coronary sinus, or primum ASD for Sx]

• PAP <5 WU, if>5 WU then PVR<2/3 SVR, PAP<2/3 SYS Pressure [baseline or when challenged with vasodilators with net Qp: Qs>1.5] (6)

Devices

Devices

Occluder diameter 2-4mm size larger than the maximum strechable defect size

Complications

Procedural success rate 95%-98%

Very rare complication (<0.5%) Rev Esp Cardiol Cardiol. 2003;56:383; (5) (6)

• Entrapment in RA structures & PV, impingement of aorta • Inability to release, withdraw• Twisting of device• Dislodgment & embolization• Thrombosis Very rare [0.05-0.2%] J Am Coll Cardiol 2004;43:302

Related to– Poor implant apposition – Poor device endothelialization– Underlying prothrombotic

Follow up

• Issues(5) (6) – Atrial arrhythmias- OAC, RF ablation– RV & LV dysfunction [Pre intervention- balloon occlusion and

reassessment of hemodynamics in poor LV function(6)]– PAH– Coexistant valvular or other cardiac lesions

• IE prophylaxis upto 6m after procedure • Aspirin atleast 100mg daily upto 6 m (6) • Echo f/up at 24 hrs, 1 m, 6m, 1 yr & then at regular intervals

Thank you

Embryology