J Am Soc Echocardiogr. 2010 May;23(5):465-95; quiz 576-7. doi: 10.1016/j.echo.2010.03.019.
Lopez L, Colan SD, Frommelt PC, Ensing GJ, Kendall K, Younoszai AK, Lai WW, Geva T.
Technique
-Axial resolution parallel to the US beam is better than lateral resolution, perpendicular to the beam- measuring Ao diam is better in PSLA bc the two pts on the walls are parallel to the US beam, as oppose to in AP4C where they are perpendicular...
-measure the intraluminal diam (inner edge to inner edge), not the outer edges, for each chamber/lumen
-measure at the moment of maximal expansion- TV/MV in diast, Ao/PV in sust, IVC at inspiration, arterirs in systole
-Show color flow b4 Doppler so you know the direction of Q
-Set gain & power to best show the outer edge of the brightest spectral Doppler envelope; exclude fuzz/feathering beyond modal velocities; only measure if clear borders
-calculate mean gradients w VTI - velocity time interval = area under velocity curve - fr vlv opening to closure at the AV/SL vlvs; and for septal defects or vssls measure it throughout the cycle, incorporating the zero velocity during pds of absent Q.
-best to avg 3 consecutive cycles for Doppler measurements
Adjusting for Body Size
-BSA is better than ht or wt alone to tract somatic growth
-Haycock Formula: BSA (m^2) = 0.24265*wt*ht --> best way to calc BSA to correlate bn heart & body size
-We index structure size to BSA bc CO is linear to BSA and near linear to hrt size
-but note heteroscedasticity- the mean values will change as BSA increases (as will the range around the mean)
-no great way to deal w this mathematically
-So, ppl now using Z scores to deal w size/age issues = # of stndrd dev fr mean for ea BSA, w +/-2 = Nl
---> don't need to rely on a predetermined relaionship bn structure size & the BSA, BUT it doesn't acct for gender & race differences etc
Recommendations: When normative data are available, the measurements of cardiovascular structures should be expressed as Z scores using the Haycock formula21 to calculate BSA.
Quantification Protocols
Pulmonary Veins, Systemic Veins, Atria
-Morphometrics:
-PVns:
-best in crab-view = high left PSSA or Suprasternal SA to show pvns into LA
-simultaneous view w & w/o color helps show the individual pvns
-Don't confuse LAA w the LUPV
-Don't confuse RMPV w the RUPV --> see RUPV fr subSA or R PS views
-SVC- no Nls established
-IVC- measure above jct w hepatic vns, just below diaph, in SubSA (w IVC elongated)
-IVC Collapsability Index = % decr w inspiration - correlates w RA P; ?how useful in kids
-IVC diam doesnt correlate to age or BSA
-LA- distance fr posterior Ao wall to pst LA wall (poor correlation w angio measurement of /LA vol)
-LA vol- @ AP4C at end-systole, just b4 MV opens
-don't foreshorten the heart
-Simpson's biplane method- check area & Ln in 4C and 2C views --> most consistent results; if index to BSA, it correlates to diast fx & MR grade
-3D LA vol correlates to MRI volumes
-RA Size- check in AP4C at end-systole, just b4 TV opens; Nls are avail in adults
RA area or RA volume calculated fr RA area and the Ln may be best at measuring the size
-3D echo also avail...
The recommended methods to assess LA size include the measurement of major-axis lengths in apical 4-chamber views and planime- tered areas in orthogonal apical views and calculation of volumes using the biplane area-length or the biplane Simpson method. The recommended methods to assess RA size include the measurement of major-axis and minor-axis lengths and planimetered areas in apical 4- chamber views. When the IVC diameter is measured, mea- surement should be performed above its junction with the hepatic veins just below the diaphragm in subxiphoid short-axis views.
-Doppler Eval
-place the cursor >5mm fr the vessels ostium for venous flows
-minimize high-pass filter for vns bc the flow is low
-PVns- fr Ap4C, PS
-SVC- fr subxiphoid or suprasternal
-IVC- fr subs, or hep vn bc it's more parallel
-for pulm/syst vns- S wave = antegrade Q in ventric systole - bc of atrial relaxation & AV vlv movement apically
-+/- biphasic S wave bc of a temporary dissoc bn atrial relax & AV vlv mvmt
-Retrograde (AbNl) -during ventric systole if signif AV vlv regurg, AV electrical dissoc w atrial cntrctn against a closed AV vlv
- D wave = antegrade Q during ventric diastole- due toatrial & ventric filling props & AV vlv patency
- Ar wave = retrograde Q diring atrial contraction- increased if decr ventric compliance
-If PVn Ar duration is > MV inflow dur during atrial systole ==> predicts incr LA & LVEDP in the setting of decr ventric compliance
-systemic D & Ar are affected by resp- insp'n --> incr D, decr Ar wave velocities bc of neg intraTx P --> measure avg over 3 consec cycles
Recommendations (Table 2): Pulmonary venous S-wave, D-wave, and Ar-wave velocities and Ar-wave duration are best measured in apical or parasternal short-axis views.
AV Valves
-Morphometrics:
-MV &TV diameter by 2D
-can estimate the area of the annulus as a circle, but really MV is elliptoid/saddle shaped
-better to check orthogonal diam x2: Area ellipse = (pi/4)*diam1*diam2, but usually over-estimate it relative to autopsy (? if artifact fr tissue fixation); published normals are avail for measures fr PSLA & AP4C; but in adults it's shown that maybe measure fr AP2C & AP3C is better, relative to CT scan measures, but in kids it can be hard to get a 2C view...
-Use largest diam of TV, MV - during pk filling of early diast, at the frame after max excursion of leaflets fr inner edge to inner edge at the hinge pts of the leaflet attchmnts. Nl data is avail for kids.
-by adult data, in setting of MS, 2D measurements oveestimates MV max size by up to 88%!, compared to 3D echo
Recommendations (Table 3): The recommended methods to assess MV and TV annular size include measurement of lateral diameters in apical 4-chamber views and anteropos- terior diameters in parasternal long-axis views and calcula- tion of areas using the area formula for an ellipse.
-Doppler Eval:
-use color to ensure best angle fr AP4C
-if possible TS or MS, use VTI fr CW tracing to calculate mean gradient
-BUT, this transvlv gradient d/o diast filling pd, andcan incr at faster HR
-can check TS or MS w a Pressure Half Time = time needed for the pk early diastolic P to decr by half.
-can check TS or MS w the Effective Orifice Area via the Continuity Equation = SV = Cross sectional area * blood flow VTI..., but limited at incr HR, more variability in kids, less good windows to mesure..., and don't correlate w cath in setting of congen AV stenosis
-in adults, quant measures of TR & MR can be done w Vena Contracta Diameter & regurg area, volume, fraction, ... but not validated in kids
-PW at MV inflow to assess LV fx- check at leaflet tips, bc pk E & A wave velocity are decr at the annulus
-Isovolumetric Relaxation Time = time fr Ao vlv close (use A2 via phonocardiogram) to MV opening, or by simultaneous measure of CW through LV in and outfliw in an AP3C view
-Deceleration Time- time fr pk E to return to baselibe in mid diastole - assess diastolic fx Sn to ventric relax'n & compliance atrial P.
-but limited bc it d.o preload, ad no god if E A fusion fr incr HR...
-LV Diastolic filling-
-E:A Velocity Ratio
-E:A Area fractions- VTI in Early diast & during Atrial contraction vs entire area under the diastolic curve
-ratio bn PVn Ar duration & MV A wave duration
-pk ventric filling rates fr (E velocity)*(MV annular cross sectional area), but better to normalize to SV:
PFRsv(s^-1) = (pkE cm/s)/(MV VTI cm), but doesn't acct for MV annular displacement away fr the transducer in diast (so really it's assesing Q twd trabsducer, not Q thru MV...)
Recommendations (Table 3): The recommended methods to assess MV inflow include measurements of E-wave and A-wave velocities, A-wave duration, deceleration time, and IVRT and calculation of the E/A ratio.
LV
-Morphometrics:
-measure LV size in syst & diast: end-diast = frame w max area, end-syst = frame w min area, but these are problematic bc min area is at diff timse in SA vs LA views bc in isovol ctrctn, the LV first contracts and then enlarges in long axis, but short axis area first incr then decr throughout isovol ctrctn ==> define end diast as the frame at which MV closes, and end-syst as the frame preceding MV opening
-can check SA measurements of the int diam, & the septal and post wall thickness in PS views
-max diam is at MV leaf tips/cords in young pts, and at paps in older pts
-only good to assess LV size if the LV is circular...
-adult studies rec assessing the minor-axis measure in PSLA bc ensure it's perpendic to the axis of the LV, but PSSA likely better in kids ... allows best plane to pick from w best walls..., and M mode SA Nls are avail.
-Volume: basal border = hinge pt bn MV leaflets; LV Ln = fr this basal border to the apical endocardium, must ensure not to foreshorten the LV...; trace the endocardial border, convention excludes the pap muscles, leaving the inside the blood pool.
-Simpson's biplane = sum of equidistant disks- few data to validate in kids - trace LV in AP4C & AP2C
-Bullet method = V = (5/6)(SA basal area)(LV Ln)
-VCFc- speed at which the LV contracts, indexed to HR... - measures end syst stress, ... PL & AL independent, = # of circumferences the LV is reduced per second (thus a velocity) thru syst
-LV Mass- little peds data- check vol like above, but trace ebdocard and epicardium, and multiply the diff by 1.05, or use 3D echo
-Systolic fx- ... SF &EF - both affected by preload = (end diast x - end syst x)/(end diast x)
Recommendations (Table 4): The recommended methods to assess LV size and function include a linear approach and a volumetric approach. The linear method involves mea- surement of short-axis diameters and wall thickness and calculation of SF and the velocity of circumferential fiber shortening adjusted for heart rate and end-systolic wall stress from 2D short-axis images obtained in parasternal or subxiphoid short-axis views. The volumetric method in- volves (1) measurement of areas from the same 2D or 3D short-axis images; (2) measurement of long-axis lengths from 2D or 3D long-axis images obtained in apical 4-cham- ber or subxiphoid long-axis views; and (3) calculation of volumes, EF, and mass using 2D or 3D measurements.
-Doppler Eval
-Tissue Doppler- PW of myocard motion - follows annulus mvmt over time, along heart's longitudinal axis
-MV- at lat and septal jct; TV at lat jct, in AP4C
-best to have sample gate <5mm
-decr Nyquist limit to maximize the deflection ampliude on the screen, bc the signal is of low velocity (usually set at 15-30cm/s); and decr the gain, w a dynamic range of 30-35dB to reduce noise fr the blood Q;
-2 negative pks - E' & A as annulus moves away fr base in diastole
-E' = ventric recoil after prior ctrctn, during early diast
-A = annular mvmt w atrial ctrctn
-S = positive deflection in ventric systole as annulus moves twd base
-IVRT' = isovol relax time' = time bn end S and start E wave
-IVCT' = isovol cntrctn time' = time bn end A and start S wave
-note that IVRT' won't correlate to IVRT (fr blood signal), espec if diast dysfx bc IVRT' isnt as affected by preld
-dP/dt = rate of pressure change - check fr MR signal- assess LV syst fx w CW signal;
-E/E' - assess LV diast fx
-MPI = myocard performance index = (IVRT + IVCT)/(ejection time) = assess combined syst and diast fx,peds Nl values are avail
-Myocardial deformation measures - strain, strain rate, ventric torsion w Doppler or Speckle tracking
Recommendations (Table 4): When tissue Doppler evalu- ation is performed at the medial and lateral MV annulus, the recommended measurements and calculations include peak e0 , a0 , and s0 velocities; IVRT0 ; IVCT0 ; isovolumic accel- eration; and the E/e0 ratio.
RV
-Morphometrics
-2D echo underestimates it compared to MRI; to complex a shape for LV measures...
-adult guidelines exist for wall thickness, size, syst fx
-RV basal border is a line bn TV leaf hing pts
-....... limited in kids....
-TAPSE- tricuspid annular plane syst excursion- assess RV fx- longitudinal shortening in AP4C, via M mode thri TV annulus; published values in kids exist
-Doppler Eval:
-TR pk velocity estimates RV P above RA P
-dP/dt fr TR jet can assess RV syst fx
-IVC collapsability index, hepatic Q indices, TV inflow velocity, TV E/E', & RV IVRT'- assess RA P & RV diast fx
-antegrade Q at PV in end diast -->c/s restrictive RV physiology
-RV MPI for combined syst and diast fx
Recommendations (Table 5): When tissue Doppler evalua- tion is performed at the TV annulus, the recommended measurements and calculations include peak e0, a0, and s0 velocities; IVRT0; and isovolumic acceleration.
Ventricular Outflow Tracts & Semilunar Valves
-Morphometrics:
-transducer plane should be parallel to the outflow tract long axis; magnify the region...
-both subvlvr outflows are elliptoid but we assume a circular cross section
-the max dimension of the narrowest subvlvr LV outflow tract diam fr PSLA in mid systole is used in adults for SV & CO calculation; RV subvlvr measured fr PSLA or PSSA; no good peds data
-AoV & PV annulus measure in PSLA/PSSA- inner edge of prox valve insertion hinge pts
-PSSA can underestimate PV & MPA size bc of oblique orientation
-systolic values correlate best w intra-op measurements
Recommendations (Table 6): The diameters of the sub- valvar LV outflow tract and aortic annulus are best measured in parasternal long-axis views during early to mid-systole. The diameters of the subvalvar RV outflow tract and pulmonary annulus can be measured in para- sternal long-axis or short-axis views during mid-systole, using the largest diameters for documentation.
-Doppler Eval:
-AP3C, R PS, suprasternal LA views for LVOT; PSLA, subs short,mod AP4C for RVOT - check max and mean gradients; assess for sublvr component w PW; grad may be falsely low if low CO...; PS might be unferestimated if large VSD or if large PDA equalizes RV P to arterial P
-note, max instantaneous grad by Doppler is diff frompk to pk measure fr cath lab- bc of pressure recovery...
-more severe AS, and an ascending Ao larger than the annnulus --> more turbulence--> less pressure recovery; in kids there is less Ao dilation than adults, so yhus higher P (better P recovery) in the Ao, thus less P gradient ==> up to 20-40% diff bn cath and echo
-Assess effective Ap vlv orifice if diseased to assess degr of AS, but unreliable bc of vlv shape... like MV a& TV
-Continuity equation to assess Ao vlv area- , but subvlvr elliptoid shape can cause variability
-Vena Contracta to quantify AR & PR in adults, limited peds data
Recommendations (Table 6): The maximum instanta- neous and mean gradients along the LV outflow tract are best measured in apical 3-chamber, suprasternal long- axis, or right parasternal views. The gradients along the RV outflow tract are best measured in subxiphoid short-axis, modified apical 4-chamber, parasternal long- axis, or parasternal short-axis views.
Aorta, Coronary Arteries, and Pulomary Arteries
-Morphometrics:
-syst diam is much bigger than diast, --> check at pt of max diam, usually mid systole
-check for prox Ao dilation or bicuspid vlv (Marfans), supravlvr AS (Williams)
-check Ao at root, STJ, prox Ao at level of RPA - can check fr high R PS view in R lat decub position
-Ao sidedness
-Arch- check at Prox Tx Arch- bn innom and LCCA, Distal Tx Arch- bn LCCA and LSCA, and Ao isthmus- narrowest Ao segment distal to LSCA
-Desc Ao at diaph level
-Cor Arts- LAD, circ, RCA
-PA- MPA, RPA, LPA
Recommendations (Table 7192): The proximal aortic di- ameters at the levels of the aortic root, sinotubular junction, and ascending aorta are best measured during mid-systole in parasternal long-axis, high left parasternal, or high right parasternal views; the proximal and distal transverse arch and aortic isthmus diameters are best measured during mid-systole in suprasternal long-axis views; and the
descending aorta diameter is best measured during mid- systole in subxiphoid short-axis views at the level of the di- aphragm. The left main, proximal and distal left anterior descending, circumflex, and proximal right coronary ar- tery diameters are best measured at the moment of maxi- mum expansion in parasternal short-axis views; the distal right coronary artery diameter is best measured at the mo- ment of maximum expansion in apical 4-chamber views with posterior angulation; and the posterior descending coronary artery diameter is best measured at the moment of maximum expansion in parasternal long-axis views with rightward posterior angulation. The main, right, and left pulmonary artery diameters are best measured during mid-systole in parasternal, high left parasternal, or supra- sternal short-axis views.
-Doppler Eval:
-asc, tx, desc Ao...
Recommendations (Table 7): The abdominal aortic Doppler pattern is best evaluated in subxiphoid short- axis views. The maximum instantaneous gradient along the ascending aorta is best measured in apical 3-chamber, suprasternal long-axis, or right parasternal views. The maximum instantaneous gradient along the aortic isth- mus is best measured in suprasternal long-axis views
and should account for the proximal velocity along the transverse aortic arch. The maximum instantaneous gra- dient along the main pulmonary artery is best measured in parasternal short-axis or modified apical views with an- terior angulation. The maximum instantaneous gradient along the right and left pulmonary arteries is best mea- sured in parasternal or suprasternal short-axis or high left parasternal views.