Echocardiography in aortic root dissection and dilatation

Echocardiography

RICHARD

W.

RICHARD

D. SPANGLER,

S. GILBERT

MOOTHART, BLOUNT,

Jr.,

in Aortic Root Dissection and Dilatation

MD MD, MD,

FACC FACC

Denver, Colorado

Six patients with aortic root dissection proved by angiography, surgery or autopsy, and SIX patlents with aortlc root dilatation were studied by echocardiography. Echocardiography was diagnostic in five of six patients with dissection and suggestlve in the sixth, disclosing anterior and posterlor dissection in three, anterior dissection in one and posterlor dissection In one. The recording of a double echo in the aorta was the diagnostic feature. Anglography was diagnostic in four of the six patients, yielded a false negative result in one and was not performed in one. Six patients with dilatation had an enlarged aortic root by echocardiography. Left ventricular size, stroke volume, election fraction, aortic regurgitant flow and velocity of circumferential fiber shortening were calculated in 11 patlents. Echocardiography was extremely helpful in the diagnosls, management and follow-up in patients with aortic dissectlon or dilatation.

Echocardiography is a noninvasive harmless bedside diagnostic technique. It is therefore especially helpful in the management of acutely ill patients and in following up those needing repeated examinations. This study reports the echocardiographic findings in 12 patients with aortic root dissection or dilatation and the associated abnormalities of aortic insufficiency, hemopericardium or abnormal ventricular function. Material

From the University of Colorado Medical Center Division of Cardiology, Denver, Colo. Manuscript accepted November 11, 1974. Address for reprints: Richard D. Spangler, MD, 4200 W. Conejos Place, Denver, Colo. 80204.

and Methods

Twelve patients, six with aortic root dissection and six with aortic root dilatation, were studied by echocardiography using a Unirad echocardiograph with a 2.5 megacycle transducer. The transducer was located in the usual position along the left sternal border and angulated to give four views: (1) the aortic root, (2) roll-off from aortic root to mitral valve, (3) the mitral valve, and (4) the left ventricular internal dimension. The study was recorded on Polaroid” prints or a strip chart recorder. The echocardiograms were evaluated by (1) examination of the echo patterns, and (2) measurements and calculations. Left ventricular volumes were calculated by the formula EDV = 59 (LVD) - 153 and ESV = 47 (LVS) - 120,’ where EDV = end-diastolic volume, LVD = left ventricular diastolic diameter, ESV = end-systolic volume and LVS = left ventricular systolic diameter. Aortic regurgitant flow was calculated by the formula QAr = QAt - QM,sp3where QAr = aortic regurgitant flow, QAt = aortic valve total flow and QM = mitral valve flow. Velocity of circumferential fiber shortening was calculated by the formula (LVD-LVS)/ dt/LVD,4 where dt = duration of minor axis shortening. Dissection was confirmed by autopsy (two cases). Angiograms were obtained in five patients at the time of the echocardiogram; in one (Case 5) an angiogram 3 months prior to the echocardiogram showed a normal ascending aorta. Three patients with dilatation had angiograms showing dilatation and aortic insufficiency. The clinical and echocardiographic data are summarized in Tables I and II.

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Results

found at surgery or autopsy (Fig. 1 to 3). In one patient with a mid-aortic echo extending through systole, an anterior dissection was diagnosed angiographically and confirmed at surgery (Case 3). One patient had a posterior double echo and a posterior intimal flap by angiogram (Fig. 4). One patient with

Aortic dissection: We found that a double echo recorded from the anterior or posterior aortic root was diagnostic of aortic dissection. Three patients had double echoes both anteriorly and posteriorly suggesting circumferential dissection, which was TABLE I Aortic Root Abnormalities

Caseno.

Aortic Root Diameter

Surgery or Autopsy

Cause

Angiogram

Al

Double Echo

FI, AML

(cm)

LVE

Aortic Root Dissection 1 2 3 4 5 6

Atherosclerosis Cystic medial necrosis Marfan’s syndrome Unknown Marfan’s syndrome Aortic stenosis and hypertension

-

Both Autopsy Surgery Neither Surgery Neither

8 9 10 11 12 * See text. + = present; A = anterior; posterior.

- = absent. Al = clinical

aortic

A,P A,P A P A,P *

... ... ...

... ...

...

+ + + -

+ -

-

-

-Aortic Root Dilatation _~_

-___ Marfan’s syndrome Cystic medial necrosis Congenital Marfan’s syndrome Cystic medial necrosis Syphilis

7

Positive Negative Positive Positive Negative* Positive

1+ 4+ 3+ a 0 cl

Autopsy Surgery Neither Neither Surgery Neither

insufficiency;

AML

=

anterior

~~~~~~~____

3+ 2+ 2+ 0

Dilated Dilated

4+ 2+

Dilated Dilated

mitral

. .

leaflet;

6.2 5.3 5.0 4.4 4.5 4.6

... .. .. ... . . ..

FI = flutter;

LVE =

-

left ventricular

+ -

+ -

+ -

+ +

enlargement;

P =

TABLE II Echocardiographic

Measurements

Case

Aortic Root Diameter

IlO.

(cm)

and Calculations

.sV

ESV

EF

@J

EAR

43 62 32 55 20 52

.., 42 62 14 -7 24

LVD

LVS

EDV

. .

...

.

...

. .

..

5.0 6.0 4.8 3.4 5.5

3.3 4.8 3.8 2.9 4.6

142 199 127 47 172

38 105 58 20 96

104 94 69 27 76

0.73 0.47 0.54 0.57 0.44

0.40 0.76 0.60 0.76 0.50 1.80

~_~~~~__~ 4.5 4.2 4.5 4.7 4.6 5.0

(QW

AML Closure Rate

Aortic Root Dissection

VW _

Aortic Root Dilatation

_~

~_~~

Al

~~__~ 1.14 0.47 0.84 0.97 0.55

1+ 4+ 3+ 0 0 0

~.~~.

7 8 9 10

6.2 5.3 5.0 4.4

9.5 5.9 5.2 4.4

7.8 3.0 3.8 3.1

437 197 157 107

248 21 60 25

189 176 97 82

0.43 0.89 0.62 0.77

1.80 1.04 0.64 0.84

15 45 19 63

174 131 78 19

0.71 1.20 1.08 1.05

3+ 2+ 2+ 0

11 12

4.5 4.6

7.1 7.8

5.1 7.0

267 307

120 209

147 98

0.55 0.32

1.66 0.96

48 35

99 63

1.13 0.51

4+ 2+

Al = clinical aortic insufficiency (grade 0 to 4+); AML closure rate = closure rate of anterior leaflet of mitral valve (cm/set); EDV = end-diastolic volume (cc); EF = ejection fraction; ESV = end-systolic volumf! (cc); LVD = left ventricular diastolic diameter (cm); LVS = left ventricular flow (cc); SV = stroke

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systolic volume

diameter (cm); OAR = aortic regurgitant flow (cc); QAT = aortic (cc); VCF = velocity of circumferential fiber shortening (cm/set).

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valve

total

flow (cc): GM = mitral

valve

fK%UX~Y

aortic root dissection had an abnormal echo pattern with multiple echoes from the aorta suggesting thickening of the aortic wall and dilatation (Case 6). Dissection was not interpreted prospectively from this patient’s echocardiogram because of the absence of a double echo, but it was confirmed by angiography 2 weeks later. A subsequent echocardiogram was diagnostic of pericardial effusion (hemopericardium found on pericardiocentesis). A later follow-up echocardiogram indicated healing with thickened aortic walls, confirmed by angiography. It is now clear that a thickened aortic wall is compatible with, but not diagnostic of dissection. Thickening was seen in acute dissection (Case 3), healed dissection (Case 6) and dilatation without dissection (Case 7). Aortic dilatation: All six patients with dilatation had an enlarged aortic root diameter ranging from 4.4 to 6.2 cm (normal 3.1 to 3.9)5 measured between the outer margins of the anterior and posterior aortic walls. Aortic insufficiency: Five of the 12 patients had fluttering of the anterior leaflet of the mitral valve, and all 5 had aortic insufficiency. Three patients with aortic insufficiency did not have such fluttering. There was no correlation between the severity of the insufficiency and leaflet flutter. Table II lists the measurements and calculations made in these patients. Patients with aortic insufficiency had an increased stroke volume and aortic regurgitant flow, but there was no correlation between aortic insufficiency and ejection fraction, closure rate

N AORTIC ROOT AMWf&LmES-MOOTMFtT

ET AL.

of the anterior mitral leaflet or velocity of circumferential fiber shortening.

Discussion Dissecting hematomas occur most frequently in the ascending aorta. More than half of the intimal tears are located within 2 cm of the aortic valve, and mortality is greatest when the tear is in this area.6,7 There is a 3 percent incidence rate of sudden death in dissecting hematoma and an 83 percent mortality rate in 1 month if the lesion is untreated.6 The disease can be rapidly progressive, and up to 66 percent of these hematomas may rupture into the pericardial sac.7 Furthermore, the dissection may extend weeks to months after its onset. A diagnostic tool that can examine the aortic root repeatedly at the bedside without risk to the patient is therefore highly desirable. Echocardiography of the aortic root fulfills these criteria and we found it to be extremely helpful in the diagnosis and management of patients with aortic root abnormalities. Echocardiography can display the following in an examination of the aortic root: (1) root diameter, (2) presence of one or more discrete walls anteriorly or posteriorly, (3) width of the aortic wall, (4) the aortic cusps. In addition, the echocardiogram visualizes changes in the anterior mitral leaflet secondary to aortic insufficiency, may demonstrate pericardial effusion and permit hemodynamic measurements to be performed to evaluate cardiac function. Our results indicate that (1) a double echo recorded from

FIGURE 1. Case 1. Aortic dissection. Echocardiogram demonstrates multiple parallel discrete echoes in the aorta (arrows). The posterior aortic wall (PAo) is displaced posteriorly into the left atrium (LA) on the rolloff view of the aorta to the anterior leaflet of the mitral valve (AML) and is not contiguous with this leaflet. AA0 = anterior aortic wall: EKG = electrocardiogram: IVS = interventricular septum: PLV = posterior left ventricular wall.

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the aortic root indicates aortic dissection; (2) the diameter of the aortic root is accurately determined by echocardiography; and (3) patients with aortic insufficiency will have increased stroke volume and aortic regurgitant flow as calculated from the echocardiogram. Validation

of method

and clinical

implications:

The validity of demonstrating the aortic root and the aortic cusps by echocardiography was shown in 1968.8 Several investigatorsg-‘l have used A and B mode scanning to reveal thoracic aneurysms. Measure-

ments obtained from suprasternal echocardiography using both A and M modes showed excellent correlation between dimensions found on echocardiography and angiography. I2 There are two reports of studies using the conventional left sternal border view of the aortic root. Millward et a1.13 reported a case of dissecting hematoma rupturing into the right atrium. The aortic root showed anterior and posterior double echoes, as seen in three of our cases. Nanda et a1.5 reported six cases of aortic root dissection. They postulated three echocardiographic findings allowing de-

-AAo

-PA0

D FIGURE 2. Case 2. Aortic dissection. A, chest film shows prominent ascending aorta. 6, aortic angiogram shows dilated aortic root, aortic insufficiency and no evidence of dissection. C, echocardiogram shows a double echo both anteriorly and posteriorly (arrows) and reveals an enlarged sot-tic root (6.2 cm). D, echocardiogram shows flutter of the descent slope (E-F) of the anterior mitral valve leaflet (AMVL), indicating aortic insufficiency. Abbreviations as in Figure 1.

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finitive diagnosis of dissection: (1) enlargement of the aortic root, (2) widening of the anterior wall or separation of the posterior wall, and (3) maintenance of parallelism between the separated walls. Enlargement of the aortic root was seen in all six of our patients with dilatation without dissection; widening of the aortic wall was seen in four of the six. Although parallelism of the double echoes was usually seen, it was not complete (Fig. 4). We found that only multiple discrete or double echoes arising from the anterior or posterior aortic wall, or both, are diagnostic of dissection, particularly when the double echoes are not continuous with the septum anteriorly or the mitral leaflet posteriorly (Fig. 1,3 and 4). Double echoes may be seen in calcific aortic stenosis; however, they are usually less discrete, and normal aortic leaflets are not seen. When dissection is present, normal leaflets may be seen (Fig. 3), thus differ-

H AORTIC ROOT AEWhMALiTlES--MoQRuRt

ET AL.

entiating dissection from calcific aortic stenosis. We suggest that all patients suspected of having a dissecting hematoma have echocardiograms in addition to angiograms. With the increased risk of angiography (mortality 1.7 percent)14 in this disease, echocardiography would be preferable for repeat evaluation of these patients. Anterior mitral leaflet echoes in aortic regurgitation: As reported previously,i5 flutter of the anterior leaflet of the mitral valve was diagnostic of aortic insufficiency (Fig. 2D). However, not all patients with aortic insufficiency had flutter of the anterior mitral leaflet. Other findings reported in aortic insufficiency are an increased descent slope, premature closure and delayed opening of the anterior mitral leaflet. We found no correlation between descent slope and aortic insufficiency (Table II), and one patient (Case 9) had premature closure and one (Case

FIGURE 3. Case 3. Aortic dissection. Echocardtogram on admission. Strip chart record with roil-off from anterior mitral valve leaflet to aorta. The anterior aortic wati (AAo) is markedly thickened. The posterior aortic wail (PAo) is displaced into the left atrium (LA) vAth a discrete double echo not contiguous wtth the anterior mitral leaflet. The patient had circumferential dissection at surgery. AL = aortic leaflets: Diss = dissection; NC = noncoronary cusp; PML = posterior mitral leaflet; other abbreviations as In Figure 1.

FIGURE 4. Case 5. Aortic dissection. Echocardiiram with roll-off from aorta to anterior mitral leaflet (AML). There is a double echo posts rioriy demonstrating dissection. and the posterior aortic wall (PAo) is displaced into the left atrium and is not contiguous with the anterior mitral leaflet. Abbreviations as in Figures 1 and 3.

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10) had delayed opening. We did find a correlation between aortic insufficiency and aortic regurgitant flow (Table II), although the degree of clinical or angiographic aortic insufficiency did not correlate with the magnitude of regurgitant flow. In conclusion, echocardiography was diagnostic of aortic root dissection in five of six patients and sug-

gestive in one and thus had a diagnostic accuracy equal to that of angiography. Echocardiography was diagnostic in the six patients with aortic root dilatation. It proved to be of great value in following up both groups of patients serially and in managing the associated conditions of aortic insufficiency, hemopericardium and cardiac enlargement.

References 1. Fortuln NJ, Hood WP, Sherman ME, et al: Determination of left ventricular volumes by ultrasound. Circulation 44:575-584, 1971 2. Danford HG, Danford DA, Ml&e JE, et al: Echocardiographic evaluation of the hemodynamic effects of chronic aortic insufficiency with observations on left ventricular performance. Circuiatiin 48:253-262, 1973 KIngsfey B, Flint GB, Raber GT, et al: Another look at echocardiography. Am J Cardiol 19:108-116, 1967 Fortuln NJ, Hood WP, Cralge E: Evaluation of left ventricular function by echocardiography. Circulation 46:26-35, 1972 Nanda NC, Gramlak R, Shah PM: Diagnosis of aortic root dissection by echocardiography. Circulation 48:506-5 13, 1973 Anageeatopoulos CE, Prabhakar MJS, Klttle CF: Aortic dissections and dissecting aneurysms. Am J Cardiil 30:263-273. 1972 7. Gore I, Hlrst AE: Dissecting aneurysm of the aorta. Prog Cardiivasc Dis 41:107-111, 1973 8. Gramlak R, Shah PY: Echocardiography of the aortic root. Invest Radio13: 356-366. 1968

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9. Tahtl E, Laustela E, Tala P: Experiences with echoaortography in thoracic aortic aneurysms. Ann Chir Gynaecol Fenn 57:5054, 1968 10. Goldberg BB, Lehman JS: Aortosonography: ultrasound measurement of the abdominal and thoracic aorta. Arch Surg 100: 652-655, 1970 11. Krlstensen JK, Hokn HH, Rasmussen SN: Uitrasonic diagnosis of aortic aneurysms. J Cardiovasc Surg 13:168-174, 1972 12. Goldberg BB: Suprasternal uftrasonography. JAMA 215:245250, 1971 13. Mlllward DK, Roblnson NJ, Cralge E: Dissecting aortic aneurysm diagnosed by echocardiography in a patient with rupture of the aneurysm into the right atrium. Am J Cardiol 30:427-431, 1972 14. Hart WL, Berman EJ, LaCom RJ: Hazard of retrograde aortography in dissecting aneurysm. Circulation 27: 1140-l 142, 1963 15. Prldle RB, Benham R, Oakley CM: Echocardiography of the mitral valve in aortic valve disease. Br Heart J 33:296-304, 1971