Quantitative evaluation of AR by echocardiography (Excerpts from Snider, 2nd ed. p.180)

Since this is less common in children, less information is available in pediatric patients.

Three methods - Assessment of AR severity

1. LV size & function
- LV Mass Mass/Vol. Ratio

Mass/Vol. Ratio: (Li et al. Am Soc Echo 7:S26, 1994)
Pure AS = 1.9 ± 0.7
AS & AR = 1.4 ± 0.4
Normal = 1.18 ± 0.3

2. Indirect Doppler indicators
- CW of AR jet for Deceleration rate & Timing of deceleration.
- PW of Aortic flow. (DTAo. and DAAo.) VTI of Forward flow / Reverse flow

3. Direct measurements by color Doppler
- AR jet by color (Jet & LVOT width)
- Measurement of RV, RF, & EROA.

General comments:
- Children with AS & AR developed symptoms and EKG changes earlier than those with AS only.

- Symptoms and EKG changes were present in all children with Mass/Vol. Ratio > 2.1 in AS and >1.4 in AS with AR. EKG changes help to identify children at increased risk of developing subendocardial ischemia.

Severity of AR by Doppler methods (All of this data is from adult studies. Preferable to not use this in infants with faster heart rate):

1. VTI Reverse / Forward flow in Ao
(Applies to both DTAo & DAAo by PW)
Mild - 8.9 ± 2.9 (1+)
Moderate - 23.6 ± 4.2 (2+)
Severe - 35.7 ± 5.9 (3+)
50.2 ± 6.5 (4+)

2. Deceleration slope
Mild - < 3 m/s2

3. Pressure half-time
Mild: > 400 ms
Severe: < 400 ms (=40% Regurgitant Fraction)

4. AR jet width / LVOT width
Mild - 19%
Moderate - 30%
Severe - 56% (3+)
80% (4+)

None of the following 3 are of any predictive value.
AR jet by color Doppler:
1) Length
2) Width
3) Area

Width of the jet / Width of LVOT from Parasternal long and short axis views (ref: Perry et al. JACC 9:952, 1987)

Area of jet / Area of LVOT in parasternal short axis
Limitations: The jet is not always circular, widens significantly after the orifice., especially of the gradient was high.

Direct measurements RV, RF and EROA:

By PW method:
Flow = CSA ´ VTI
RV = FlowAoV - FlowPV
RF = RV / FlowAoV

Shown to be accurate in predicting RV and RF.
(Ref: JACC 7: 1273, 1986, Circ 87:841, 1993 and JACC 23:443, 1993.)

By 2D and PW Doppler:
Forward SV = LVEDV - LVSDV
C.O. CSA ´ VTI (via MV or PV)
RV = Forward SV - C.O.
EROA = RV / VTI of Regurgitant jet by CW.
EROA > 25-30 mm2 correlates with severe AR in surgry.

By color Doppler (PISA) technique:
EROA = Regurgitant flow / Regurgitant velocity = 2p2 ´ VAL /Vo.
Regurgitant SV (RV) = EROA ´ VTI by CW.


Conduction System - Normal Heart vs. AVSD (One aspect of it)

Images from Kirklin/Barratt-Boyes Cardiac Surgery 3rd edition (2003)

AVSD (p 813)
Normal Heart (p 15)

Conduction system in VSDs:
Figure below shows the AV node and His bundle relationship to membranous VSD and inlet-muscular VSD. Note: Inlet-muscular VSD is different from inlet-VSD in AVSD. The latter is shown in the first figure above.
(From Anderson RH, Wilcox BR. J Cardiac Surg. 1992;7:17-34)


Thromboelastogram (TEG) - Result interpretation

TEG result parameters:
R value – Measure of coagulation time from start to initial fibrin formation.
Prolonged when there is coagulation factor deficiency, anticoagulation, severe thrombocytopenia or hypofibrinogenemia

K value: Represents clot kinetics – measuring time taken for a certain level of clot strength is reached i.e. width of the clot reaches 20 mm.
Prolonged when there is coagulation factor deficiency, hypofibrinogenemia, thrombocytopenia or thrombocytopathy.

Alpha angle: is the angle between midline and a line tangential to the developing “body” of TEG trace. Represents clot kinetics of clot build up and cross-linking.
This is increased in hypercoagulable states and decreaed in thrombocytopenia or hypofibrinogenemia.

MA: Maximum amplitude is the maximum width of the “body” of TEG trace. Represents ultimate clot strength.
Reflects platelet number and function & interaction of platelet with fibrin.
Increased in hypercoagulable states.
Decreased in thrombocytopenia, thrombocytopathy and hypofibrinogenemia.

Lysis: LY30 and LY60 – Clot lysis at 30 min and 60 min after MA.
Expressed as % of amplitude of TEG trace at 30 and 60 min in comparison to MA.
Increased in states of fibrinolysis.

Platelet function testing:
Sonoclot - an alternative for TEG. Uses ultrasonic vibration to stimulate clot formation.

VerifyNow (Accumetrics, San Diego, CA)
Clot Signature Analyzer (CSA, Xylum, Scarsdale, NY) – currently, not approved by FDA
Platelet function analyzer, PFA-100 (Dade Behring, Miami, FL)
PlateletWorks (Helena Laboratories, Beaumont, TX)

(Excerpts from Cardiopulmonary bypass Edited by Sunit Ghosh, Florian Falter and David Cook. 1st edition. Cambridge University Press, New York).

Another reference:
Vig, S. et al. Thromboelastography: a reliable test? (Blood, Coagulation and Fibrinolysis 2001;12:555-61)
Storage of sample over 90 min, showed an instability for 30 min. But, after those 30 minutes, the results were reproducible. Therefore, TEG requires a formal operating procedures established for each institution to be consistent.