diagnosis of aortic root dissection by...

Diagnosis of Aortic Root Dissection by EchocardiographyBy NAVIN C. NANDA, M.D., RAYMOND GRAMIAK, M.D.,

AND PRAVIN M. SHAH, M.D.

SUMMARYSix patients with aortic root dissection confirmed by angiography, surgery, or autopsy were stud-

ied by echocardiography. All showed marked parallel widening of the anterior (16 to 21 mm)and/or posterior (10 to 13 mm) aortic walls together with enlargement of the aortic root image.(Normal mean aortic wall thickness 5.7 mm, SD 1.2; aortic valve disease patients 6.7 mm, SD 1.5.)In five patients slender aortic valve cusps were recorded moving to the periphery of the innerlumen in systole and not extending to the outer lumen. This finding is useful in excluding calci-fication of the aortic valve which may produce confusing multiple echoes within the aortic root.Two patients showed 8 to 20 mm variations in the width of the aortic image with slight changein the direction of the transducer indicating that the dissecting hematoma was not uniform inthickness. Other associated findings on the echogram seen in three patients included the demon-stration of pericardial fluid collection and mitral diastolic flutter suggestive of aortic regurgitation.Demonstration of enlargement of the aortic root with marked parallel widening of anterior and/orposterior walls appears to be specific for aortic root involvement in dissecting aneurysm of theaorta.

Additional Indexing Words:Aortic wall thickness ACatheter in right ventricle Ao

kortic root enlargementrtic valve disease Ultrasound

Aortic dissecting aneurysm

D ISSECTING ANEURYSM has long beenrecognized as a highly lethal form of aortic

disease. Recent advances in medical and surgicalmanagement of this disease have resulted inconsiderable improvement in the outlook andprognosis.' 6 Since untreated dissecting aneurysmsare rapidly fatal in 60 to 90% of the cases,7 8 it isimperative that an early and accurate diagnosis bemade so that treatment may be initiated as rapidlyas possible. The diagnosis by clinical methods andby plain chest film roentgenography9 sometimespresents difficulties. By far the most definitivemethod of diagnosis is intravenous or retrogradeaortography. However, this is nondiagnostic in acertain proportion of cases with dissecting aneu-

From the Departments of Medicine (Cardiology) andRadiology, University of Rochester School of Medicine andDentistry, Rochester, New York.

Supported in part by NIH Grant No. 1-ROl-HL-15186-01and MIRU contract No. PH-43-68-1331. This work wascarried out while Dr. Shah held an American HeartAssociation Teaching Scholarship in Cardiology.

Address for reprints: Navin C. Nanda, M.D., CardiologyUnit, University of Rochester Medical Center, Rochester,New York 14642.

Received February 13, 1973; revision accepted forpublication April 26, 1973.

506

rysm.'0 A safe, noninvasive, nonionizing techniquelike echocardiography which can be used even atthe bedside would be especially welcome if it couldcontribute to the diagnosis of this condition. Thepurpose of this report is to describe echocardio-graphic findings in patients with proven aortic rootdissection.

Materials and MethodsSix patients who had aortic root involvement in

dissecting aneurysm of the aorta, confirmed byangiography, surgery, or autopsy, were studied byechocardiography. Table 1 summarizes their clinicaldata.

All ultrasonic examinations were carried out using acommercially available echograph (Picker) and a 2.0megacycle transducer. Continuous recordings weremade on 35 mm film by means of a Fairchildoscilloscope record camera and a dual-beam oscillo-scope operating as a slave. Aortic root echoes wereobtained by a method previously described."1 Themitral valve was first located from a left parastemalposition, utilizing the third or fourth intercostal space.Medial and cephalic rotation of the transducer from themitral valve position passes the beam through the aorticroot, outlining the walls and the valve cusps within.The transducer was angled slightly in various directionsand any changes in the width of the aortic root imageproduced by this maneuver were recorded.

In each patient the width of the aortic root wasmeasured in mm from the outer limits of the dominant

Circulation, Volume XLVIII, September 1973

by guest on May 20, 2018

http://circ.ahajournals.org/D

ownloaded from

http://circ.ahajournals.org/

AORTIC ROOT DISSECTION AND ULTRASOUND

Table 1

Clinical Findings in the Present StudyMain Diagnosis

No. Patient Age & Sex symptom confirmed by Comment

59 M Chest pain51 F Chest pain

56 M57 M

Heart failureChest pain

59 M Heart failure76 F Chest pain

SurgeryAutopsy

AortogramAortogramSurgerySurgeryAutopsy

Died during surgeryDeath from cardiactamponadeAlive and well*Dealth from cardiactamponadeAlive and well**Death from cardiactamponade

*3 year follow-up**recently operated

echo configuration of the wall at the end of systole (fig.1). Wall thickness was similarly determined from theouter limit of the major echo to the inner aspect of thelesser component. When technical limitations precludedseparation of wall components, the width of theconglomerate echo representing the aortic root marginwas used. These parameters were compared to similarmeasurements obtained from a previous study conduct-ed in normal persons and patients with aortic valvedisease.12 The first three cases in the present study were

examined by the same equipment used to generate thedata in the previous study. Changes of equipment to anewer model revealed no obvious differences in wallthickness measurements. The ultrasonic technique usedin all examinations was similar. Time-varied gain was

AO

RESPPHOIO

ECG

Figure 1

Schematic representation of an aortic root echocardiogram ina patient with aortic root dissection. The small double-headedarrows indicate the thickness of the dissecting hematomawhile the large arrows show the width of the aortic rootimage measured at end systole. D = width of the dissectinghematoma; AO aorta; RESP = respirations; PHONO =phonocardiogram; ECG = electrocardiogram; S1 = first heartsound; S2 = second heart sound.


adjusted to equalize the intensity of the major echoesemanating from the anterior and posterior aorticmargins. No suppression of the near structures wasused. Sensitivity was regulated to record cusp echoes,which are of approximately the same intensity as thoseof the inner aortic margins in dissection. Aortic valvecusp echoes were studied for the character of motionpattern and for evidence of thickening.12 Mitral valveechograms were analyzed for presence of diastolicflutter and prominent "a" waves. The heart walls werestudied for evidence of pericardial fluid.

Results

The ultrasonic findings in the present study are

summarized in table 2. All patients in this studyshowed enlargement of the aortic root. Themeasured outer diameter of the aortic image variedfrom 42 to 53 mm. The mean width of the aorticroot in the normal heart is 35 mm, SD 4.2 (table 3).The most striking echocardiographic finding provedto be marked widening of both anterior andposterior aortic walls which occurred in four of thepatients studied (fig. 2). Increased thickness of onlyone aortic wall was present in the remaining twocases. In Case 2 the widening was localized to theanterior wall, the site of dissection demonstrated atautopsy (fig. 3). The other case with localizedechocardiographic abnormality (Case 5) showedwidening of the posterior aortic wall which was

found at surgery to correspond to a small dissectinghematoma in that area. The anterior wall in thiscase was normal (fig. 4). The extent of aortic wallthickening as measured by echocardiography was

striking when the values obtained are compared tonormals and patients suffering from aortic valvedisease. In the dissection group anterior wallinvolvement produced images which ranged from16 to 21 mm in width while posterior wall

12

W.J.A.S.

34

H.M.F.K.

56

J.D.E.P.

507



ownloaded from


NANDA, GRAMIAK, SHAHTable 2

Echocardiographic Findings in the Present Study

Aortic root

Aortic valve cusps

NormalNormalNormalNormalThickenedNot well seen

involvement produced 10 to 13 mm wide walls. Theresults of a previous study from our laboratory(summarized in table 3) demonstrated the meanaortic wall thickness to be 5.7 mm (SD 1.2) innormal individuals and 6.7 mm (SD 1.5) in patientswith aortic valve disease.12An important diagnostic aspect of the image of

the widened wall is the parallelism that ismaintained between the inner and outer limitsthroughout the cardiac cycle. The outer componentof the thickened wall was usually represented by aheavier line than the inner margin. Some variationwas present in the appearance of the space betweenthe margins of the thickened wall. Solid lines,speckling or mottling, as well as absence of anyechoes were observed. Some patients exhibitedmore than one pattern of echoes within the

Table 3

Echocardiographic Findings in Patients Without AorticRoot Dissection*

Widthmm

Normal

Heart Disease(Normal Aortic Valve)

Aortic Stenosis

Aortic Insufficiency

35.0(4.2)N 4435.8(5.5)N 4137.0(5.1)N 1240.4(6.7)N 14

Aortic rootWall

thicknessmm

5.7

(1.2)N 455.7(1.5jN 426.7(1.5)N 136.0(1.1)N 14

The figure at the head of each grouping represents the meannumerical value for that category. The quantity in bracketsis the standard deviation, while N denotes the number of ob-servations. Although the mean values and standard deviationsare expressed to the first decimal, measurement in individualcases is accurate only within 1 mm.

Abstracted from a previous study from our laboratory."2

widened wall with small changes in transducerangulation or instrument sensitivity.

In all but one of our patients, slender valve cusps

moved to the periphery of the inner lumen insystole and did not extend to the outer lumen. Onepatient (Case 5) showed some evidence ofthickening of valve cusps and in another thinleaflets were identified, but their motion patternwas not well demonstrated.

Slight variation in the direction of the sonic beamduring recording produced changes in the width ofthe aortic root image in two patients. These rangedfrom 8 to 20 mm in magnitude. In the remainingpatients little or no change (less than 5 mm) couldbe demonstrated in the width of the aortic rootduring beam angulation.

Echocardiographic evidence of aortic regurgita-tion was present in three patients. This consisted offine oscillations of the mitral valve in diastole13together with prominent "a" waves. Three patientsshowed evidence of large pericardial fluid collec-tions on the echocardiogram.

DiscussionThe role of echocardiography in the diagnosis

and evaluation of various forms of heart disease hasbeen well established.14-19 It is harmless, noninva-sive, and can be used as a bedside investigationeven in seriously ill patients. Previous studies fromthis laboratory", 12 have demonstrated the feasibili-ty of studying the aortic root by echocardiographyand have also validated the anatomic componentsof the root using indocyanine green dye duringcardiac catheterization.The echocardiographic findings which enabled us

to make a definitive diagnosis of aortic rootdissection in our cases were a) enlargement of theaortic root (42 mm or more), b) marked widening(16 to 21 mm) of the anterior wall of the aorta atthe root level and/or a wide separation of theposterior aortic wall ( 10 to 13 mm), and c)


No.

1

2

3

4

56

Patient

W. J.A. S.H. M.F. K.J. D.E. P.

Widthmm

46

5142

53

47

43

Ant. wallthicknessmm

16211620417

Post. wallthicknessmm

13410111010

508



ownloaded from



0,-~_-, .,-~~~~

_

- _..~ -* ~ -

Figure 2Case 1. Aortic root echogram reveals marked parallel widening of both anterior and posterior walls.Aortic valve cusps are slender and show normal motion pattern. D = width of the dissecting hematoma;AO = aorta; RESP = respirations; PHONO = phonocardiogram; ECG = electrocardiogram.

maintenance of parallelism between the separatedmargins of the walls in every patient. In addition,preservation of normal motion pattern of aorticvalve cusps was observed in all but one.Echograms of two patients also showed marked

variations in the width of the aortic root image withslight change in the direction of the transducer.This was thought to be related to the nonuniformthickness of the dissecting hematoma.The ultrasonic diagnosis was made retrospective-

ly in three of the cases studied. In the remainingthree, the diagnosis was suggested from theechocardiographic examination prior to aortogra-phy or when the aortogram was inconclusive.

Associated findings on the echogram could be ofvalue to the clinician. Demonstration of pericardialfluid collections by echocardiography may indicatethat the dissection has ruptured into the pericardialsac. Echograms of three of our patients showedlarge anterior and posterior pericardial spaces andin all of them the dissection was found to haveruptured into the pericardial cavity at autopsy.Mitral diastolic flutter and large "a" waves sugges-tive of aortic regurgitation were observed in threecases. Appearance of these in patients withCirculation, Volume XLVIII, September 1973

dissecting aneurysm could be another clue of aorticroot involvement leading to aortic incompetence.

Recently a case has been described in which thepresence of dissecting aneurysm found at angiogra-phy was first suggested by an ultrasound recordingfrom the aortic root. The ultrasonic studiesdemonstrated widening of the anterior and poster-ior aortic walls shown as four, rather than two,simultaneously pulsating structures, delineating thetrue and false lumen.20

Differential Diagnosis

Certain conditions have to be considered in thedifferential diagnosis of this entity.

Dilatation of the aortic root commonly seen inaortic valvular lesions and in aneurysms of theascending aorta produces a wide aortic root imageon the echocardiogram. However, images of normalwidth are obtained from the anterior and posterioraortic walls.

It may be difficult to make the diagnosis of aorticroot dissection in the presence of calcific aorticvalve disease. In this condition multilayered echoeswithin the aortic lumen may be seen and these maygive an erroneous appearance of widening ofanterior and/or posterior walls of the aorta (fig. 5).

P~_

r_lm



ownloaded from


NANDA, GRAMIAK, SHAH

'; .O-; ,waM9' a;_%.qb -

or~- Zm .-k

-

m

-r .-Figure 3

Case 2. The arrows show the limits of widening of the anterior wall of the aortic root. In the upper

panel, valve cusp motion can be seen limited by the inner margin of the dissection. Note that the pos-

terior wall shows normal thickness. In the lower panel, the beam was moved during recording anddemonstrates a marked change in the width of the aortic root. This patient showed a localized hematomainvolving the anterior wall while the posterior wall was normal.

-~ - ----w-~--

~ ~ ~~W*¶

-- - ~e

..'L. w P.


510



ownloaded from



w~~ 5 = _ --,W

- .1

Figure 5

two patients with extensive calcific aortic valve disease and no evidence of dissec-thick multilayered echoes within the aortic root may simulate widening of the

These echoes, which are produced by deposits ofcalcium in the aortic valve, however, are usuallythicker than those produced by aortic walls andshould be easily recognized. Moreover, the valveleaflet motion may be restricted or there may be no

recognizable cusp motion. Therefore, it is importantto attempt to document aortic leaflets with little or

no structural thickening and showing normalmotion in the inner lumen before confidentlymaking the diagnosis of aortic root dissection.Occasionally, one can suspect aortic root dissectioneven in the presence of aortic valve disease. Case 5illustrates this (fig. 4). Even though aortic rootechoes show some evidence of valve thickening, thevalve elements produce discontinuous or nonlinearimages. At surgery, a small intimal tear which hadresulted in the formation of a pouch posteriorlynear the noncoronary cusp was found. Thus, aorticdissection can be diagnosed in some patients withaortic valve disease if the cusp motion is not undulyrestricted and the valve not heavily calcified.

Echograms of patients in the Coronary Care Unitwith a Swan-Ganz catheter in the pulmonary arteryor of patients in whom a pacing catheter hasdislodged from the apex of the right ventricle and isfloating in the outflow tract may show a strong echoanterior to the aorta. The catheter echo may closelyfollow the movement patterns of the aortic root andmay be mistaken as the outer margin of the anteriorwall (fig. 6). Multiple echocardiographic record-ings showing the catheter moving asynchronouslywith the aortic root or demonstration of a similarcatheter echo in the right ventricular cavity whenrecording the mitral valve usually clarifies thediagnosis.

Apparent thickening or widening of the posteriorwall may be seen in some conditions. Presence offluid in the transverse sinus of the pericardium can

give a double contour to the posterior aortic wall19(fig. 7). However, the two contours tend to benonparallel. In aortic root dissection, parallelismbetween the separated walls is maintained. Occa-

Figure 4Case 5. Echocardiogram demonstrates separation of the posterior aortic wall as indicated by the ar-rows. The width of the anterior wall is not increased. Valvar elements show evidence of thickening.


RESPPHONO

ECGG

Echocardiograms fromtion. The presence ofaortic walls.

511



ownloaded from


NANDA, GRAMIAK, SHAH

-

Figure 6

Echoes from a Swan-Ganz catheter (C) closely follow the movement of the anterior wall of the aorta(left). Another recording from the same patient made a few seconds later shows the catheter movingasynchronously with the aortic root. The nonparallelism of the images helps to rule out dissection.

- ___ -

. p

Figure 7

The panel on the left was recorded from a patient with a large pericardial effusion and shows non-

parallel widening of the posterior margin of the aortic root, probably due to fluid in the transverse sinusof the pericardium. On the right, a non-parallel linear echo (origin is obscure) is seen behind the aorticroot in the left atrial cavity. Note that the posterior aortic wall is clearly shown to be of normal widthand that the added "line" does not have the motion pattern of the aortic wall.

512

-- - --- 1 .

W 'W. - -

" J" W p- - 1 ilicir -

- *4'%or v

Ir

--A ia'i'tg. lx.j by guest on May 20, 2018


ownloaded from



sionally, one echoes "lines" in the left atrium (fig.7). They also tend to be nonparallel to the posterioraortic margin and are generally seen deep in theleft atrial cavity. These echoes could be arising fromthe walls of the pulmonary veins at their insertioninto the left atrium.

Demonstration of an enlarged aortic root withmarked parallel widening of anterior and/orposterior walls appears to have diagnostic value foraortic root involvement in dissecting aneurysm ofthe aorta. We have so far not seen this combinationof findings in any other condition. Widening ofeither anterior or posterior aortic wall in thepresence of extensive calcific aortic valve diseaseshould be viewed with caution. False positivediagnoses of aortic root dissection can be avoidedby strict adherence to the diagnostic criteria,especially maintenance of parallelism of thewidened image of the wall, a stronger echo fromthe outer limit of the wall as compared to the innermargin, and demonstration of normal aortic valvecusps. Although the present study is not aprospective one, to date no false positive diagnoseshave been made. One patient with a suggestiveechocardiogram and chest pain has not undergoneaortography because of his precarious clinicalcondition, although clinical findings support thediagnosis of dissection. We are aware of nonegative examinations in patients proved to haveaortic root dissection, though a dissection limited toa lateral wall, theoretically, could be missed by thismethod. WVhile the number of cases we havestudied utilizing the echocardiographic method isnot large, it is evident that this noninvasivetechnique is useful in the diagnosis of dissectioninvolving the aortic root.

References1. DEBAKEY ME, HENLY WS, COOLEY DA, MORRIS GC

JR, CRAWFORD ES, BEALL AC JR: Surgical manage-ment of dissecting aneurysms of the aorta. J ThoracCardiovasc Surg 49: 130, 1965

2. AUSTEN WG, BUCKLEY MJ, MCFARLAND J, DESANCTISRW, SANDERS CA: Therapy of dissecting aneurysms.Arch Surg 95: 835, 1967

3. WHEAT MW JR, PALMER RF, BARTLEY TD, SEELMAN

RC: Treatment of dissecting aneurysms of the aortawithout surgery. J Thorac Cardiovasc Surg 50: 364,1965

4. HARRIS PD, MALM JR, BIGGER JT JR, BOWMAN FO JR:Follow-up studies of acute dissecting aortic aneu-rysms managed with antihypertensive agents. Circula-tion 35 (suppl I): I-183, 1967

5. WHEAT MW JR, HARRIS PD, MALM JR, KAISER G,BOWMAN FO, PALMER RF: Acute dissecting aneu-rysms of the aorta. J Thorac Cardiovasc Surg 58:344, 1969

6. DAILY PO, TRUEBLOOD HW, STINSON EB, WUERFLEINRD, SHUMWAY NE: Management of acute aorticdissections. Ann Thorac Surg 10: 237, 1970

7. DEBAKEY ME, COOLEY DA, CREECH 0 JR: Surgicalconsiderations of dissecting aneurysm of the aorta.Ann Surg 142: 586, 1955

8. HIRST AE, JOHNS VJ, KIME SW: Dissecting aneurysmsof the aorta: A review of 505 cases. Medicine 37:217, 1958

9. EYLER WR, CLARK MD: Dissecting aneurysms of theaorta: Roentgen manifestations including a compari-son with other types of aneurysm. Radiology 85:1047, 1965

10. SHUFORD WH, SYBERS RG, WEENS HS: Problems in theaortographic diagnosis of dissecting aneurysm of theaorta. New Eng J Med 280: 225, 1969

1 1. GRANIIAK R, SHAH PM: Echocardiography of the aorticroot. Invest Radiol 3: 356, 1968

12. GRAMIAK R, SHAH PM: Echocardiography of thenormal and diseased aortic valve. Radiology 96: 1,1970

13. WINSBERG F, GABOR GE, HERNBERG JG, WEISS B:Fluttering of the mitral valve in aortic insufficiency.Circulation 41: 225, 1970

14. EDLER I: Ultrasound cardiography in mitral valvestenosis. Amer J Cardiol 19: 18, 1967

15. FEICENBAUM H: Echocardiographic diagnosis of peri-cardial effusion. Amer J Cardiol 26: 475, 1970

16. JOYNER CR, HEY EB, JOHNSON J, REID JM: Reflectedultrasound in the diagnosis of tricuspid stenosis. AmerJ Cardiol 19: 66, 1967

17. FEIGENBAUM H: Clinical applications of echocardiogra-phy. Progr Cardiovasc Dis 14: 531, 1972

18. JOYNER CR: Echocardiography (Editorial). Circulation46: 835, 1972

19. GRAMIAK R, SHAH PM: Cardiac ultrasonography: Areview of current applications. Radiol Clin N Amer9: 469, 1971

20. MILLWARD DK, ROBINSON NJ, CRAIGE E: Dissectinganeurysm diagnosed by echocardiography in a patientwith rupture of the aneurysm into the right atrium.Amer J Cardiol 30: 427, 1972


513



ownloaded from


NAVIN C. NANDA, RAYMOND GRAMIAK and PRAVIN M. SHAHDiagnosis of Aortic Root Dissection by Echocardiography

Print ISSN: 0009-7322. Online ISSN: 1524-4539 Copyright © 1973 American Heart Association, Inc. All rights reserved.

is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231Circulation doi: 10.1161/01.CIR.48.3.506

1973;48:506-513Circulation.

http://circ.ahajournals.org/content/48/3/506Wide Web at:

The online version of this article, along with updated information and services, is located on the World

http://circ.ahajournals.org//subscriptions/

is online at: Circulation Information about subscribing to Subscriptions:

http://www.lww.com/reprints Information about reprints can be found online at: Reprints:

document. Permissions and Rights Question and Answer in the

Permissions in the middle column of the Web page under Services. Further information about this process is availableOnce the online version of the published article for which permission is being requested is located, click Request

can be obtained via RightsLink, a service of the Copyright Clearance Center, not the Editorial Office.Circulation Requests for permissions to reproduce figures, tables, or portions of articles originally published inPermissions:



ownloaded from

http://circ.ahajournals.org/content/48/3/506

http://www.ahajournals.org/site/rights/

http://www.lww.com/reprints

http://circ.ahajournals.org//subscriptions/


diagnosis of aortic root dissection by...

Documents