Doppler & CFI Echocardiography

Doppler

• gives hemodynamic info

  • provides direct assessment of blood flow

    • 2D and M-mode provide structural info

• baseline = no flow

  • velocity = 0

Types of doppler used:

• CW: no aliasing / no range resolution

• PW: aliasing / sample volume for range resolution

Spectral Analysis

• graphic display of the doppler signal

• shows blood flow velocities over time (m/sec)

• Dp waveform will give info about:

  • direction of flow

    • toward trdx: above baseline

    • away from trdx: below baseline

  • velocity of flow

    • peak velocity is critical in Dx of stenosis

  • intensity of flow

  • timing of flow

    • compare w/ EKG

Audio signal of doppler:

• higher velocity = higher pitch

  • very high velocity will result in a hiss

    • means stenosis

• signal from heart is not as “clean” as those found in vessels

  • flow within heart is more turbulent d/t:

    • pressure gradients

    • chamber size differences

      • LA < LV

Specifics with echo doppler:

• angle correction is not necessary

  • use various windows to be parallel to flow

    • must know:

      • best views to Dp various areas / valves / pathology

      • direction of flow relative to trdx

• valve clicks / slaps can be heart

  • and visualized on the spectrum

  • used to help place beam or sample volume

• use PW / CW for the quantification of stenosis, regurg, and direction of shunt flow

Color Flow Imaging (CFI)

• form of PW Doppler

• BART map used

  • never invert color bar

  • Blue Away

  • Red Towards

• must know direction of flow

• used to:

  • assess direction of blood flow

  • help place sample volume or Dp beam

  • detect and evaluate insufficiency / regurgitation

Eccentric

• term used to mean “not centered / not central”

• “off to one side”

• direction of eccentric jet will be opposite of leaflet affected

  • ie: when Ant MV leaflet is damaged, the eccentric jet will hug the Posterior LA wall

CFI, Regurg & Insufficiency is most often “eyeballed” using CFI:

• compare area of AI jet to LV cavity and anterior MV leaflet

• compare area of MR jet to LA cavity and Pulm veins

• compare area of PI jet to RVOT

• compare area of TR to RA cavity and IVC / Hepatic V’s

Grading Regurgitation:

• Trivial / Trace

• Mild

  • RJA <20%

• Moderate

  • RJA 20-40%

• Severe

  • RJA >40%

  • flow reversal noted in Pulm V’s or IVC

Pulsed Wave (PW)

• used to find velocities across valve

  • sample volume placed at leaflet tips

• used to evaluate regurgitation

  • sample volume “walked” behind the valve being interrogated

    • called ‘mapping’

Continuous Wave (CW)

• can perform w/ image (on screen)

• can perform w/ blind pedoff probe

  • more sensitive

• used to find velocities across beam

• used to evaluate regurgitation

Doppler Side note:

• Regurgitation and transvalvular velocities are dependent on HR and BP

• Best practices say we should take and report current BP at time of exam

Doppler Exam

• 5 basic trdx positions to record bl flow

  • Apicals

  • Lt parasternal (long and short)

  • Rt parasternal (pedoff used)

  • Suprasternal

  • Subcostal

• Sweep speeds

  • slow → fast

  • 5, 50, 10, 150 mm/sec

Apical 4/5/2/3 Chamber

• Optimal doppler views

  • record largest amount of Dp / CFI patterns from this window b/c parallel to flow

• assess w/ doppler and CFI:

  • MV - PW + CW

  • TV - PW + CW

  • LVOT - PW (walk along IVS until valve slaps seen)

  • AoV - PW + CW

  • Pulm veins - PW (1-3 cm into Pulm vein)

  • Septums

    • not parallel to flow across defects, but some info rendered

PLAX

• CFI

  • used to evaluate flow across AoV and MV

    • first clue for presence of regurg and/or stenosis

  • used to evaluate IVS

  • used to evaluate eccentric jets

• Dp

  • limited in this view b/c perpendicular to normal flow

    • VSD

      • will be parallel to shunt across the anterior septal wall

RVIT tilt doppler:

• used to evaluate flow across TV

  • use CFI

    • first clue for presence of regurg and/or stenosis

  • use PW and CW

PSAX doppler:

• Dp PV and TV at the base

  • b/c parallel to flow across these valves

  • use PW and CW

    • some use PW only at PV

      • d/t MPA bifur

• CFI

  • may be used to evaluate TR, TS, PI, PS and atrial septum

    • PSAX at base

  • evaluate ventricular septum

    • at mid to apical PSAX

Suprasternal doppler:

• pt in supine position w/ head tilted slightly back

• most useful for eval of Asc and Desc Ao

  • perform under certain circumstances

  • will use PW and CW images to assess Ao

• will use CW pedoff probe for AS

Rt Parasternal doppler:

• pt in RLD position

• CW pedoff probe used to eval AS

Subcostal doppler:

• may perform Dp on difficult pt’s that could not be performed in traditional windows

  • COPD

  • off axis heart

• best view to locate septal defects

  • b/c parallel to shunt flow

  • use CFI across septum

    • place PW Dp in CFI jet to obtain sample

• CFI to evaluate IVC and hepatic veins

  • PW can be used too

Normal Mitral Valve (MV) Flow:

• diastolic flow

  • flow toward trdx / above baseline

  • systolic flow reversal represents MR

    • seen below baseline

• resembles M-mode pattern

  • double peaked

    • E-wave in early diastole

    • A-wave represents atrial kick

  • peak velocity of E-wave averages ~0.9 m/sec

    • 0.6 - 1.3 m/sec

    • E > A

Normal Aortic Valve (AoV) Flow:

• systolic flow

  • A5C

    • flow away from trdx / below baseline

  • suprasternal / rt parasternal

    • flow toward trdx / above baseline

  • diastolic flow reversal represents AI

• fast acceleration in early systole

  • slower decel to end systole

• peak velocity averages ~1.35 m/sec

  • 1.0 - 1.7 m/sec

Normal Tricuspid Valve (TV) Flow:

• Doppler spectral trace resembles MV

• lower peak velocity than MV

  • averages ~ 0.5 m/sec

  • 0.3 - 0.7 m/sec

Normal Pulmonary Valve (PV) Flow:

• similar to AoV flow

  • longer duration than Ao flow

    • d/t slightly longer RV ejection time

• more gradual accel / decel of flow

• lower peak velocity than AoV

  • averages ~0.75 m/sec

  • 0.6 - 0.9 m/sec

Normal IVC / SVC / Hepatic V’s / Pulm Veins Flow:

• blood flows into atria during ventricular systole

• blood flows into atria during early ventricular diastole

• blood flow will reverse w/ atrial contraction

  • occurs in late diastole

    • when atria actively contracts

  • called “atrial reversal” (AR) or “a wave”

    • normally <25 cm/sec