제 9강 임신 일삼분기 태아초음파 검사
일삼분기 태아 심장의 생리
초음파검사 장단점
초음파검사 방법
선천심기형의 signs
진단이 안되는 심기형
진단이 가능한 심기형
초기 임신의 태아 심장 생리적 특징
(1). Low compliance due to
Less organized myocardial arrangement
Fewer sarcomeres per unit
Smaller diameter
Higher heart rate
(2). Greater cardiac afterload due to
High placental resistance
(3). Underdeveloped intrinsic renal function
to counteract any tendency to fluid retention
따라서 아주 쉽게 NT, DV, TR 이 생긴다.
1st T-echo의 장점
① 정상을 확인해서 고위험 산모의 불안감소
② CHD시 조기에 안전하게 TOP
③ 염색체 검사나 유전상담을 위한 시간적 여유
④ 분만시기, 장소에 대한 조기결정가능
1st trimester fetal echo 단점
① 태아위치나 초음파 주사각이 적절하지 않은 경우가 많다.
② 질식초음파 이용시 심장의 입체적 이해가 어렵다.
③ 심장의 크기가 작아서 관찰안되는 선천심기형이 있을 수 있다.
④ 임신이 진행되면서 나타날 수 있는 선천심기형은 발견 안된다.
1st trimester fetal echo 관찰 내용
① 상복부단면상: Abdominal situs, stomach, aorta-lt, IVC-rt
② 사방단면상: Heart axis, size, left 45, ¼ of the chest 4CV,
each 4 chamber confirm, AV valve offsetting
③ 오방단면상: Aorta from LV
④ 우심실유출로상: PA from RV
⑤ 삼혈관상: similar size, converging
1st Trimester markers of CHD
① Abnormal cardiac axis: normal 35 º -60 º (median 47 º)
② Increased NT: 95 percentile
③ Abnormal DV: 95 percentile, or abnormal a wave
④ TR: over half of the systole, velocity over 80 cm/sec,
⑤ ARSA
선천성 심기형 의심 sign (NT, DV, TR외)
ü Cardiomegaly
ü Ascites
ü Peripheral edema
ü Pleural effusion
ü Pericardial effusion
Increased NT with normal chromosome
¨ 95th percentile: 2.5 mm 35.5%
¨ 99th percentile: 3.5 mm 23%
¨ 56% of major CD increased NT (Hyett, 1999)
¨ Meta-analysis done by Makrydimas, 2003
N=68492, criteria NT >99th
Sensitivity-31%, specificity-96.6%, LR-24
NT 증가정도에 따른 처치
u echocardiogram at 18-20 weeks: NT > 95th
u referral for early echocardiogram: NT > 99th , NT > 95th and cardiac sign
Normal NT: reduce background risk by half
Can NT be used for CHD screening?
Detects around 15% of CHD by many authors
Ductus Venosus
DV와 NT는 유의하게 연관되어 있지 않다. (Maiz et al, 2008)
Tricuspid Regurgitation
TR was present 39(8.5%) of the 458 chromosomally normal fetuses
82(65.1%) of the 126 with trisomy 21
44(53%) of the 83 with trisomy 18, 13
TR decreases with gestation, increases with NT
In chromosomally normal fetuses, TR positive in 46.9% of the fetuses with CHD,
5.6% of the fetuses without CHD.
likelihood ratio-8.4 (Faiola S et al, 2005)
Cardiac lesions that may be overlooked in 1st trimester
1. Developmental lesions
Mild aortic/pulmonary stenosis
Mild mitral/tricuspid valve abnormalities
Co Ao
Tumors
Cardiomyopathies
2. Septal defects
VSD
Primum ASD
AVSD
TOF with normal size PA
Abnormal PVR
Cardiac lesions that can be detected in the 1st trimester
Tricuspid atresia
Pulmonary atresia (with or without VSD)
Mitral atresia
Aortic atresia
HPLHS
TGA
Double inlet ventricle
AVSD
Truncus arteriosus
TOF
isomerism
Normal 1st Trimester scan is sufficient?
Fetal heart is developing & growing fast: Esp, semilunar valves
Small heart size to resolution: small VSD, pulm veins
Reassess 20th-22nd week !