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The clinical recognition of dissecting aortic aneurysm
CLINICAL STUDIES
The Clinical Recognition of Dissecting Aortic Aneurysm
EVE E. SLATER, M.D. ROMAN W. DeSANCTIS,
M.D.
Boston, Massachusetts
From the Department of Medicine (Cardiac Unit), Massachusetts General Hospital and Harvard Medical School. This study was supported by U.S. Public Health Service Grant I-IL-5196. Requests for reprints should be addressed to Dr. Eve E. Slater, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114. Manuscript accepted August 14, 1975.
The clinical, roentgenologk and laboratory flndlngs In 124 patients wlth dksectkg aneurysm of the aorta are reported. In 53 patients the dlssectlon occurred ln the ascending aorta (“poxlmal” dlssectlon), and In 71 patient8 the site of orlgln was the descending thorack aorta (“dktal” dlssectlon). Certain dktkct clinical differences between the groups were apparent. Ahhough hypertension wa8 an important predkpo&g factor, R was slgnlflcantty more common In distal dtssectlon, as wpI atheroeclerosls. Back pain and hypertenston on hoapltal presentatkn cfraracterized patients wlth distal dksectkn. Conversety pattents wlth proximal dlssectlon were younger and had a slgnlfkantly hlgher Incidence of Marfan’s syndrome, cystk medial necroek, anterior chest pain, puke defklts, neurokglc compromke, &tk lnsufflclency and congestive heart failure. In both groups, syncope appeared to correlate well wlth the occurrence of cardiac tamponade. Chest roentgenograms almost always &owed an abnormal aortlc contour. Aortk angkgraphy, when performed, was usuatly confirmatory of the dlagnosk. Advances in the therapy of a disease require simultaneous advances in diagnosis, and this is surely true of dissecting aortic aneurysm. Since the introduction of surgical therapy by De Bakey et al. [l] in 1955 and medical treatment by Wheat et al. [2] in 1964, rapid identification and precise definition of dissecting aortic aneurysm have become mandatory. Historically, clinical recognition of%the disease has been slow in developing. Although originally described in 1761 by Morgagni [3] and officially named “aneurysme dissequant” by Laennec [4] in 1819. it was not until 1856 that antemortem diaonosis was first accomplished by Swaine and Latham [5]. Likewise, almost one century later, in 1950, in an extensive review of 735 cases published up to that time, correct antemortem diagnosis had been made in only 10.6 per cent of patients [6].
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TABLE
I
Sex, Age Range and Duration 124 Patients
of Disease in
Dissection
Men Women Age range (yr) Mean age (yrl Duration Acute (<2 wk) Subacute (2-6 wk) Chronic (>6 wk)
Proximal (N = 53)
Distal (N = 71)
36 17 19to75 55.4
54 17 42t0ai 62.0
41 1 11
55
MATERIAL AND METHODS The present series was gathered from a review of discharge summaries, surgical reports and autopsy records of the Massachusetts General Hospital for the period of time from January 1963 through December 1973. The composition of the series is largely clinical: 38 patients II
Predisposing Factors in 124 Patients with Dissecting Aortic Aneurysm Dissection
Cause Known hypertension* Evidence of prior hypertension Total with presumed hypertension* Marfan’s syndrome? Cystic medial necrosis’ Arteriosclerotic aorta’ No known predisposing factor
Proximal (N = 53)
0 istal (N = 71)
26 8 34 5 16 0 8
55 13 68 1 4 9 1
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surgery or to cardiac catheterization were excluded from this report. Classification was modified from that of De Bakey et al. [7], who identified three types of dissecting aneurysms on the basis of the site of origin and the extent. According to De Bakey’s classification, types I and II dissection begin in the ascending aorta, the intimal tear usually being located just above the sot-tic valve. Type I dissection extends for variable distances beyond the ascending aorta, whereas type II dissection is confined to the ascending aorta. In contrast, type Ill dissection originates distal to the arch vessels in the descending thoracic aorta, usually just beyond the origin of the left subclavian artery. Type Ill dissection may rarely progress in a retrograde fashion into the arch and ascending aorta. For the purposes of this review, because of their similar clinical behavior, types I and II will be referred to collectively as “proximal” dissection, and type Ill will be termed “distal” dissection. The duration of the disease was judged to be “acute” if present for less than two weeks prior to admission, “subacute” if present for two to six weeks, and “chronic” if present longer than six weeks. Patients with subacute and chronic dissection were included in the series only if adequate information relative to signs and symptoms was available on retrospective review of their records. RESULTS
Classification of Patients. Age and sex distribution for the 124 patients are presented in Table I. Men predominated in this series by a ratio of 2.7 to 1. Peak incidence was in the sixth and seventh decades, the mean age of patients with proximal disease being almost 10 years less than that of patients with distal disease. Distal dissection occurred more commonly than proximal dissection by a ratio of 1.3 to 1. Ninety-six patients (77 per cent) had acute dissection, seven patients (6 per cent) had subacute dissection, and 21 patients (17 per cent) presented with chronic disease.
l Denotes statistical significance between the two groups of P _< 0.01 when p values were calculated either by the chi square niethod and the Yates’continuity correction or by the Fischer’s Exact Test. ‘/’ Denotes p > 0.01 and p 20.05.
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were seen in consultation by one of us (R.W.D.). An additional 52 cases were acquired from the angiographic files of the cardiac catheterization laboratory. Although most of these patients were included in the hospital discharge diagnostic category of “dissecting aortic aneurysm,” a further 15 cases were identified by reviewing this source. Seven further patients were obtained from the list of patients undergoing surgery for dissecting aneurysm. Finally, 12 cases were found in a search of our pathology files. Thus, of the 124 patients, 112 were identified from clinical sources, and only 12 from postmortem files. Patients with
iatrogenic dissection secondary to cannulation at cardiac
6 IO
Recognition of dissecting aortic aneurysm has increased over recent years because of more widespread appreciation of the disease and the advent of increasingly sophisticated diagnostic technics, most notably angiography. Thus accurate and prompt diagnosis should now be possible in well over 90 per cent of cases. Nonetheless, a high index of suspicion by the physician is still the single most important factor in making the diagnosis. To reexamine the clinical features of dissecting aortic aneurysm, we have reviewed the records of 124 patients, seen within the past 10 years at the Massachusetts General Hospital, in whom the diagnosis was established either by angiography, at surgery or on autopsy examination. Results of medical and surgical management of these patients will be presented in a subsequent report.
TABLE
DeSANCTlS
Volume
Table II reflects the predisPredisposing Factors. posing factors. There was a history of defin/te hypertension in 55 of 71 patients (78 per cent) with distal disease and in 26 of 53 patients (49 per cent) with proximal dissection. An additional 13 patients in the distal group and eight ,patients in the proximal group
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had evidence of prior hypertension as indicated by otherwise unexplained left ventricular hypertrophy seen on electrocardiogram or at autopsy. Thus 96 per cent of those with distal dissection and 64 per cent with proximal lesions had actual hypertension or evidence of prior hypertension; a highly significant difference between these two groups (p <0.0005) exists. Six patients (5 per cent) had overt Marfan’s syndrome, five with proximal lesions. The sixth patient, aged 51 years, who presented with a history of typical pain one year prior to admission and progressive symptoms of congestive heart failure, was found to have a dissection beginning at the left subclavian artery without retrograde extension. His aortic root and sinuses of Valsalva were strikingly dilated, but the upper half of the ascending aorta and aortic arch were of normal caliber. In addition, 20 patients (16 per cent) without clinical evidence of Marfan’s syndrome were found to have cystic medial necrosis on histologic examination of the aorta. In 14 of these 20 patients, a history of hypertension was also extant. Six patients had cystic medial necrosis and proximal dissection without apparent preexisting hypertension. Among these were five patients in whom aortic valvular disease and cystic medial necrosis appeared to coexist with proximal dissection. In two patients, aged 37 and 43 years, neither with a history of hypertension or Marfan’s syndrome, a bicuspid aortic valve, cystic medial necrosis and proximal dissection were confirmed at autopsy. In three patients, aged 5 1, 56 and 60 years, cardiac catheterization supported evidence of the combined lesion which was confirmed at surgery. The sixth patient with cystic medial necrosis and without hypertension was a 34 year old man who had experienced protracted industrial exposure to dimethylhydrazine ((CH&-N-NH*). Nine patients had evidence of a dissection within an atherosclerotic aorta. All nine had distal disease, and eight were hypertensive. In only one patient could a history of recent and severe chest trauma be elicited, and this patient had coexistent cystic medial degeneration. Likewise, in only 17 of the 124 patients (14 per cent) could a his-
tory of possibly relevant excitement or effort be linked to the actual onset of pain. These included such diverse activities as heavy lifting, leaning on a pneumatic drill, bowling, straining at stoof and tension during a court trial. No patient in this series had aortic dissection related to pregnancy, although our hospital does not provide obstetrical service. Nine patients (7 per cent) in the current series had no identifiable predisposing factor.
TABLE f II
DeSANCTlS
Presenting Symptoms Dissection
Symptom --Pain Pain alone Pain with syncope Pain with congestive heart failure Pain with cerebrovascular accident Congestive heart failure without pain Cerebrovascular accident without pain Abnormal chest roentgenogram without pain
Proximal (N = 53)
Distal (N = 71)
47
69
37 4
66 2
4
1
2
0 4
0
2
0
0
2
Presenting Symptoms. The presenting symptoms of the 124 patients are summarized in Table Ill. Severe pain of acute onset occurred as a presenting symptom in 116 of the 124 patients (94 per cent). Other less common but previously recognized presenting symptoms included syncope, stroke and congestive heart failure with or without associated chest pain. Among the patients with congestive heart failure, all eight with proximal disease had aortic insufficiency to account for their left ventricular decompensation. The one patient with congestive failure and distal dissection has previously been described as having Marfan’s syndrome with aortic regurgitation secondary to annuloaortic ectasia. Six patients (5 per cent) presented with painless dissection. Two patients, both with distal disease, had asymptomatic widening of the aortic arch, and in four patients with proximal disease, dissecting aneurysms were discovered at surgery for severe aortic valve regurgitation. The location of pain as it occurred in proximal and distal disease is summarized in Tables IV and V, in which pain has been categorized both with respect to the site of major pain (Table IV) as well as the sites of any pain (Table V). A significantly larger number of patients with proximal dissection experienced the major site of pain in the anterior chest. Conversely, the posterior chest, usually the interscapular area, was the site of major pain significantly more often in distal dissection. When all the sites of pain (rather than just the major pain) are considered, half of the patients with proximal disease had only anterior chest pain, in contrast to only 6 per cent of those with distal disease. Although 36 per cent of patients with distal dissection had isolated posterior pain as opposed to only 10 per cent of patients with proximal lesions, 65 of 69 (94 per cent) with distal dissection reported the presence of at least some back pain.
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DeSANCTlS
The pain was migratory in 82 of the patients with pain (71 per cent), and the path of migration often, although not invariably, corresponded to the path of aortic vessels involved in the dissection process. Pain in the jaw and throat was somewhat more common in proximal dissection. Low back pain was experienced in both groups although with higher frequency in those with distal dissection. Physical Findings. A summary of the pertinent physical findings is contained in Table VI. Forty patients with distal dissection (56 per cent) were hypertensive when initially seen, as opposed to only five (9 per cent) with proximal dissection. In contrast, only one patient with distal dissection was hypotensive as opposed to 12 with proximal dissection. Of these 12 patients, five had cardiac tamponade, three had intrapleural or intraperitoneal rupture, and four had extensive dissection involving the brachiocephalic vessels. Pulse deficits, which included either absence or a clear-cut diminution of a pulse, were found in approximately one half of the patients with proximal disease, and predictably, the brachiocephalic vessels were most frequently compromised. Pulse deficits were significantly less common in patients with
distal dissection and tended to involve the left subclavian and femoral vessels, although these vessels were about equally affected by the distal propagation of dissections originating proximally. The one patient with distal disease and right subclavian compromise had evidence of retrograde dissection to the aortic root. In no case of distal dissection was a carotid pulse deficit recorded.
TABLE IV
Relationship of Site of Major Pain to Origin of Dissection in Patients Presenting with Pain
-
TABLE VI
Dissection Site of Major Pain
-
Chest, anterior* Chest, posterior* Chest, both anterior and posterior Neck and throat Abdomen Suprapubic l
A pulsatile sternoclavicular joint was noted in one patient with proximal dissection. The murmur of aortic regurgitation was heard in 36 patients with proximal disease (68 per cent) and in four patients with distal disease (6 per cent), three of whom were known to have had prior aortic regurgitation. In two of these four patients, the murmur was due to long-standing and severe hypertensive disease. The third patient had Marfan’s syndrome with annuloaortic ectasia. Retrograde dissection accounted for the murmur in the fourth patient. Neurologic deficits predominated in patients with proximal disease. These deficits included cerebrovascular accidents, ischemic paraparesis, ischemic peripheral neuropathy and disturbances of consciousness. In this series, hemiparesis and coma were seen only in patients with proximal dissection, and the neurologic compromise of distal disease involved only the lower extremities. Miscellaneous Complications. No patient had symptoms specifically referable to mesenteric infarc-
Distal (N = 69)
31 (65%) 5 (10%)
19 (27%) 39 (57%)
4 4 3 0
Denotes statistical significance
TABLE V
Proximal (N = 47)
Two Groups Dissection
8 0 2 1
(p _< 0.01).
Dissection
Anterior only” Posterior only* Anterior and posterior Total with any pain in back* Jaw and throatt Low back
Proximal (N = 47)
Distal (N =‘69)
23 5 19 23 12 6
4 25 20 65 7 13
(50%) (10%) (40%) (50%) (26%) (13%)
(6%) (36%) (57%) (94%) (10%) f21%)
* Denotes statistical significance of p < 0.01, Denotes p > 0.01 and p 5 0.05.
Hypertension (blood pressure > 150/90 mm Hg bilaterally)* Hypotension (blood pressure Q 100 mm Hg bilaterally)* Pulse deficit Total patients with deficit* Total pulse deficits* Right carotid Right subclavian Left carotid Left subclavian Right femoral Left femoral Pulsatile sternoclavicular joint Murmur of aortic regurgitation* Neurologic manifestations Total patients with neurologic manifestations* Cerebrovascular accident lschemic peripheral neuropathy lschemic spinal cord damage Coma, altered consciousness l
Denotes statistical significance
t
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Proximal (N = 53)
Physical Finding
Relationship of Location of Any Pain to Site of Origin of Dissection
Site of Any Pain
Pertinent Physical Findings in the
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Distal -
(N = 71) 40
5 12
1
27 43
11 14 0 1 0 3 3 7
10 11 1 8 8 5 1 36
0 4
19 7 6 1 5 0.01).
4 0 2 2 0
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tion, although one patient had autopsy-proved superior mesenteric dissection. She was obtunded on presentation and had evidence of right carotid, right coronary and right renal artery occlusion as well. Three patients presented with oliguria. In only one was this related to bilateral renal infarction. Two others had acute tubular necrosis. Ten additional patients had evidence of unilateral renal arterial involvement by the dissection at autopsy. Six had proximal dissection and four had distal dissection. One patient experienced hemoptysis. Hemorrhagic pleural effusion was recorded at the time of presentation in 11 patients, nine with distal dissection and two with proximal dissection. Ten patients had leftsided effusion and one had bilateral effusions. Horner’s syndrome was observed in one patient with proximal disease. Three patients had evidence of acute myocardial infarction on electrocardiogram. Two had proximal and one had distal dissection; all three died. Subsequent autopsy confirmed dissection of the right coronary artery in two patients: in the third patient, postmortem examination was not performed. His electrocardiographic changes were in the anterior precor-
dial leads. Other Laboratory Studies. Pertinent laboratory information is presehted in Table VII. A small number of patients presented with hematocrit values less than 30 per cent, and almost two-thirds of the paTABLE VII
Laboratory Studies in Patients with Dissecting Aneurysm*
Anemia Leukocytosis Elevated SGOT level Elevated LDH level Elevated bilirubin level
16/105 55/89 6/75 42173 13/66
115%) (62%) (8%) (58%) (20%)
* Numerator indicates the number of patients with the abnormality and the denominator indicates the number of patients with results available for interpretation,
TABLE VIII
DeSANCTlS
tients had a polymorphonuclear leukocytosis at the onset of their disease. Serum glutamic oxaloacetic transaminase (SGOT) values were usually within normal limits, but lactic dehydrogenase (LDH) and bilirubin levels were more often elevated. The electrocardiographic abnormalities in the 120 patients with an electrocardiogram available for analysis are summarized in Table VIII. Notable are the relative paucity of acute ischemic changes and the high frequency of left ventricular hypertrophy with strain pattern. Roentgenographic Findings. The roentgenographic findings are recorded in Table IX. In 85 per cent of patients in the current series, an abnormal chest roentgenogram suggestive of the diagnosis was found either initially or in retrospect. These abnormalities included (1) an abnormal aortic contour, (2) a wide superior mediastinum and (3) the “calcium” sign, a pathognomonic separation of aortic wall ‘intimal calcification from the outer margin of the aorta which occurred in 10 of the 71 patients (14 per cent) with distal disease. Of the 124 patients, angiography was performed in 103-39 with proximal disease (74 per cent) and 64 with distal disease (90 per cent). In 38 of the 39 patients with proximal lesions and in all the 64 patients with distal dissection who underwent angiography, diagnosis was confirmed by this technic. In all but four patients with proximal disease, a definite or probable site of origin of the dissection could be identified. Angiography was attempted but was unsuccessful in two patients with distal disease because of tortuous aortic vessels. Only one major complication of angiography occurred, and that was in a patient who sustained right ventricular perforation with cardiac tamponade which was successfully treated. COMMENTS Effective therapy for dissecting aortic aneurysm mandates the need for early and accurate diagnosis of this entity. Several features emerge from our
Electrocardiographic Findings Dissection
Electrocardiographic Abnormalities
Proximal (N = 50)
Distal (N = 70)
Normal Left ventricular hypertrophy Old myocardial infarction New myocardial Infarction Bundle branch block S-T + T wave abnormalities Electrical alternans Low voltage
15 21 5 2 2 10 1 1
17 30 10 1 6 9 0 0
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TABLE IX --
Roentgenographic Findings Dissection
Abnormalities on Chest Roentgenogram
Proximal (N = 45)
Definitely abnormal aortic contour “Possibly” abnormal aorta Normal chest roentgenogram “Calcium” sign Pleural effusion
34 8 3 0 2
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study and from past reports that may be helpful in suggesting the diagnosis and predicting the site of origin of the dissection. As in other series, we found that this disease affects men more frequently than women, with a peak incidence in the sixth and seventh decades [8]. The predominance of distal dissection over promixal dissection in the patients we studied contrasts with the experience of others, most notably the extensive review of Hirst et al. [8], in which approximately 60 per cent of 505 cases occurred in the ascending aorta. Two factors likely account for this difference, and both relate to the fact that dissecting aneurysms that occur in the ascending aorta are more lethal than distal dissections. First, ours was largely a clinical series, whereas that of Hirst et al. was based on postmortem examination. Second, we serve as a referral hospital for patients with dissecting aneurysm, and those with distal dissection are more likely to survive long enough to be transferred to our hospital for ther-
By far the most common symptom of dissecting aneurysm is pain, which is almost universally present unless loss of consciousness accompanies the dissection. Severe pain was present in 94 per cent of the patients we studied. Although not specifically analyzed in this report, the patients’ descriptions of the pain were frequently peculiarly appropriate to the actual event. Terms such as “tearing” or “ripping” were often noted. Migration of the pain from the initial location as the dissection extends to other sites, as occurred in almost three quarters of our patients, is common and affords an important clue to the diagnosis of dissecting aneurysm. In contrast with the findings of Lindsay and Hurst [9], but in agreement with those of Burchell [13], our experience would also indicate that the location of pain may be of some help in suggesting the site of origin of the dissection. Pain that was exclusively in the anterior portion of the chest was significantly more frequent with proximal dissection, whereas pain that was exclusively posterior was significantly more common with distal dissection. Pain felt simultaneously anteriorly and posteriorly can be present with either a proximal or distal dissection. However, the absence of back pain strongly mitigates against a dissection originating in the descending thoracic aorta, as it was present in 94 per cent of patients with distal dissection. Although very rare, dissecting aneurysm can occur painlessly [ 141. The occurrence of syncope in aortic dissection may bear a special significance. Syncope without focal neurologic signs occurred in six of the 124 cases studied. In five cases, the patients were subsequently found tu have rupture of the dissection into the pericardial cavity with cardiac tamponade. The sixth patient died at cardiac catheterization before the presence of pericardial fluid could be demonstrated, but cardiac tamponade had been suspected clinically. Congestive heart failure, when present, is usually a feature of proximal dissection, and it is almost invariably due to free aortic regurgitation. Sometimes the congestive failure may mask the presence of aortic regurgitation. In one patient in this series, dissecting aneurysm was suspected clinically and the patient was in profound congestive heart failure, but no murmur of aortic regurgitation could be heard. The presence of disproportionately bounding pulses in the face of severe congestive heart failure suggested that aortic incompetence was present, and this was indeed confirmed by subsequent angiography and surgery. The diagnosis of dissecting aortic aneurysm can often be made with reasonable assurance from the physical examination alone. It has been observed‘by several investigators that patients with dissecting an-
apy. Regarding etiology, hypertension was again confirmed as an extremely important factor, and significantly more so in distal than in proximal dissection. This coincides with the experience of Lindsay and Hurst [ 91. Six patients had Marfan’s syndrome and 20 patients had pathologic evidence of cystic medial necrosis. Of interest are the five adults in this report who presented with the triad of cystic medial necrosis, aortic valve disease and proximal dissection in the absence of any hypertension, Marfan’s syndrome or other underlying cause. This association has been previously noted by Core and Seiwart [ 101 and McKusick et al. [ Ill. The question of the relationship of environmental exposure to the development of cystic medial necrosis is raised because of the one patient in this series who exhibited that pathologic entity and who had a history of industrial exposure to dimethylhydrazine. Experimentally, it has long been known that cystic medial necrosis and aneurysmal dilatation with dissection of the aorta can be induced in rats fed a diet containing a large amount of Lathyrus odoratus (sweet pea) [ 121. The active principle is believed to be aminopropionitrile (HsN-CH2-CH2-CN). Although chemically unrelated to aminopropionitrile, dimethylhydrazine ((CH&N-NH2) has also been shown to adversely affect collagen metabolism experimentally (personal communication, Dr. M. V. Barrow, September 12, 1972). It is unclear whether arteriosclerosis alone predisposes to dissection [8]. Nine of the patients we studied had an intimal tear occurring within an arteriosclerotic aorta. lt would seem likely that the arteriosclerosis was contributory rather than coincidental.
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FIgwe 1. Mechanisms of aortic regurgitation in dissecting aortic aneurysm. A, circumferential tear with widening of aortic root and separation of the aortic cusps, B, displacement of one aortic cusp substantMly below the level of the others by the pressure of the dissecting hematoma, C, actual disruption of the annular leaflet support leading to a flail cusp.
eurysm appear to be in shock, yet the blood pressure may actually be elevated when it is measured [9,13,14]. This was true in our experience, especially with distal dissection. Differences in arm blood pressures and the finding of absent or reduced arterial pulses are key diagnostic clues. Pulses may be lost either by direct compression of the lumen of the artery by extension of the dissection into it, or by an intimal flap that blocks the orifice of the vessel. Pulse loss may be transitory. Restoration of pulses may be achieved by reentry locally into the artery itself, distally into the aorta, thereby decompressing the false lumen, or by movement of the intimal flap away from the orifice. Deficits involving the brachiocephalic vessels were found almost exclusively in proximal dissection, although both proximal and distal dissections may extend far enough peripherally to occlude the femoral arteries. The development of new aortic insufficiency in a patient with chest pain is an important clue to the presence of proximal dissection and was present in two-thirds of our cases. Aortic incompetence in dissecting aortic aneurysm may be produced by three mechanisms (Figure 1). First, the dissection may dilate the root of the aorta, widening the annulus and making it impossible for the leaflets to coapt in diastole. Second, with an asymmetric dissection, the pressure of the dissecting column against the aortic root may depress one leaflet substantially below the level of the others, thus rendering the valve incompetent. Third, the annular support of the leaflets or the leaflets themselves may be torn such that they are unable to support the column of blood in the aorta in diastole. The mechanism of aortic incompetence is
of some relevance in regard to surgical therapy. When aortic insufficiency is produced by elther of the first two mechanisms, simple decompression of the aorta by surgically excising the intimal tear and occluding the false lumen may result in resuspension of the aortic leaflets such as to restore competence. However, if the annular support is disrupted, the aortic valve will very likely have to be replaced at the time of operation. Although not common, neurologic deficits are important sequelae of dissecting aneurysm and may be presenting symptoms. The neurologic deficits of dissecting aortic aneurysm have been summarized by Weisman and Adams [ 161 and are of three types. First, cerebrovascular accident secondary to occlusion of the arteries supplying the brain may occur, and this is much more frequent wlth proximal dissection. Second, ischemic neuropathy may result from the blockage of a peripheral artery, particularly the femoral arteries, and may occur by the distal extension of either a proximal or distal dissection. Third, the spinal cord may be subjected to ischemic damage as a result of severing particularly the intercostal arteries, which are the major suppliers of blood to the spinal cord. A pulsatile sternoclavicular joint, described by Logue and Sikes [ 171 as a clue to the diagnosis of dissection of the ascending aorta, was noted in one of the patients studied. Many additional phenomena may result from dissecting aneurysm as a consequence or compression of surrounding structures by a dilated aorta, by occlusion of any artery arising from the aorta, or by perforation and hemorrhage of the dissection. Thus, three
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of the patients with proximal dissection had acute myocardial infarction from compressive occlusion of a coronary artery. Occlusion of the renal arteries may cause renal infarction, and dissection into the arteries supplying the mesenteric vascular bed can result in mesenteric infarction. One of the patients with proximal dissection had Horner’s syndrome from pressure against a cervical sympathetic ganglion. Other reported manifestations not encountered in our series are left recurrent laryngeal nerve pressure resulting in vocal cord paralysis and hoarseness, superior mediastinal syndrome, pulsating neck masses [8], hemorrhage into the tracheobronchial tree, and extension of a proximal dissection into the atrial septum and atrioventricular conduction system causing heart block [ 181. Except for chest roentgenography and aortic angiography, the laboratory is not of great help in making the diagnosis of dissecting aneurysm. The electrocardiogram is useful in a negative sense, that is, failing to show evidence of myocardial infarction in a patient whose history might suggest one. Left ventricular hypertrophy is common, reflecting prior hypertension. An elevated LDH level is frequent, and presumably reflects hemolysis of blood in the false channel. Hemolysis may also elevate the serum bilirubin level. Leukocytosis is usually present in the patient who presents shortly after the onset of pain, and anemia may result from leakage of the dissecting aneurysm. Chest roentgenography is very important because the aortic contour is usually abnormally widened, as was the case in 85 per cent of the patients studied. A localized bulge in the aorta may suggest the site of origin of the dissection [ 191. Wide separation of intimal calcification from the outer border of the aortic knob (present in 14 per cent of the patients with distal dissection) is virtually pathognomonic if the aortic knob is calcified. A left pleural effusion was present in 9 per cent of the patients, the majority of whom had distal dissection. Although often hemorrhagic, pleural effusions may accumulate simply as a result of exudation around the dissection.
DeSANCTIS
The great advance in the diagnosis of dissecting aneurysm has, of course, been contrast angiography. Although we originally performed it by injection of dye into the pulmonary artery and opacification of the aorta in the venous phase, we have increasingly shifted over to retrograde aortic procedures as the hazards of this approach have proved to be minimal. The site of origin of the dissection can often be accurately pinpointed, which is an important consideration if surgery is to be undertaken. On the other hand, as Shuford et al. [20] have pointed out, angiography is not foolproof, and a number of pitfalls may occur in diagnosing dissection of the aorta. These include such problems as faint opacification of the false lumen, unusual tearing of the intima, and equal simultaneous opacification of both channels. Recent correlations of angiography with survival from aortic angiography suggest a better prognosis in patients with nonopacified false channels [21]. Those without false lumen filling had both a better survival rate and a lesser incidence of subsequent localized aneurysm formation than.patients with angiographic filling of false channels. In addition to trying to define the site of origin and the extent of the dissection, angiography of the distal circulation is desirable, especially if surgery is contemplated. For example, either or both renal arteries or a major mesenteric vessel may be fed from the false channel, and surgical obliteration of the false lumen can compromise the circulation of vital organs perfused from it. Although none of the patients in this series was studied with echocardiography prior to December 1973, it should be noted that this technic has recently been reported to be of value in the diagnosis of proximal dissection [ 22-241. Despite all technical advances, however, it is worth emphasizing again that the single most important factor in diagnosing dissecting aortic aneurysm is a strong index of suspicion on the part of the physician .
REFERENCES 1.
2.
3.
4.
5.
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DeBakey ME, Cooiey DA, Creech 0 Jr: Surgical considerations of dissecting aneurysm of the aorta. Ann Surg 142: 586, 1955. Wheat MW Jr, Palmer RF, Bartfey TD. Seeiman RC: Treatment of dissecting aneurysms of the aorta without surgery. J Thorac Cardiivasc Surg 50: 364, 1964. Morgagni GB: DeSedibus et Causis Morborum per Anatomen indagatis Libri Quinque. Venetiis. ex Typog Remondiufana, 1761. Laennec RTH: De I’Auscultation Mediate, ou Traite du Diagnostic des Maladies des Poumons et du Coeur, voi 1, Paris, Cher J-A Brossand, et J-S Chaude, 1819, p 411. Swaine K, Latham PM: A case of dissecting aneurysm of
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6.
7.
8.
9.
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the aorta. Trans Path Sot London 7: 106. 1855-1856. Levinson DC, Edmeades DT, Griffith GC: Dissecting aneurysm of aorta: its clinical, electrocardiographic, and iaboratory features: report of 58 autopsied cases. Circulation 1: 360. 1950. DeBakey ME, Heniy WS, Cooiey DA, Crawford ES, Beaii AC: Surgical management of dissecting aneurysms of the aorta. J Thorac Cardiovasc Surg 49: 130, 1965. Hirst AE Jr, Johns VJ Jr, Kime SW Jr: Dissecting aneurysm of the aorta: a review of 505 cases. Medicine 37: 217. 1958. Lindsay J Jr, Hurst JW: Clinical features and prognosis in dissecting aneurysm of the aorta. A m-appraisal. Circu-
CLINICAL RECOGNITION OF DISSECTING AORTIC ANEURYSM-SLATER. DeSANCTlS
10. 11,
12.
13.
14. 15.
16. 17.
lation 35: 880, 1987. Gore I, Seiwart VJ: Dissecting aneurysm of the aorta: pathologic aspects. Arch Pathol 53: 12 1, 1952. McKusick VA, Logue RB, Bahnson HT: Association of aortic valvular disease and cystic mediil necrosis of the ascending aorta: report of four instances. Circulation 16: 188,1957. Ponseti IV, Baird WA: Scoliosis and dissecting aneurysm of the aorta in rats fed with Lathyrus cdoratus seeds. Am J Pathol 28: 1059, 1952. Burchell HB: Aortic dissection (dissecting hematoma; dissecting aneurysm of the aorta). Circulation 12: 1068, 1955. Cohen S, Liimann D: Painless dissecting aneurysm of the aorta. N Enal J Med 271: 143, 1964. Anagnostopoios CE, Prabhakar MI, Kiile CF: Aortic df sections and dissecting aneurysms. Am J Cardiil 30: 263, 1972. Weisman AD, Adams RD: Neurological complications of dissecting aortic aneurysm. Brain 67: 69. 1944. Logue RB, Sikes C: New sign in dissecting aneurysm of the aorta; pulsation of sternoclavicutar joint. JAMA 148: 1209, 1952.
18.
19.
20.
21.
22.
23.
24.
May lo,1976
Yacoub MH, Schottenfeld M, Kittle CF: Hematoma of the interatrial septum with heart block secondary to dissecting aneurysm of the aorta. A clinicopathologic entity. Circulation 46: 537, 1972. Lodwick GS: Dissecting aneurysms of the thoracic and abdominal aorta: report of 6 cases, with a discussion of roentgenologic findings and pathologic changes. Am J Roentgen01 69: 907, 1953. Shuford WH, Sybers RG, Weens HS: Problems in the aortographic diagnosis of dissecting aneurysms of the aorta. N Engl J Med 280: 225, 1969. McFarland J, Willerson JT, Dinsmore RE, Austen WG, Buckley MJ, Sanders CA, DeSanctis RW: The medical treatment of dissecting aortic aneurysms. N Engl J Med 286: 115, 1972. Nanda NC, Gramiak R, Shah PM: Diagnosis of aortic root dissection by echocardiography. Circulation 48: 506, 1973. Moothart RW, Spangler RD, Blount SG Jr: Echocardiography in aortic root dissection and dilatation. Am J Cardiol 36: 11, 1975. Brown OR, Popp RL, Kloster FE: Echocardiographic criteria for aortic root dissection. Am J Cardio136: 17, 1975.
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The Clinical Recognition of Dissecting Aortic Aneurysm
EVE E. SLATER, M.D. ROMAN W. DeSANCTIS,
M.D.
Boston, Massachusetts
From the Department of Medicine (Cardiac Unit), Massachusetts General Hospital and Harvard Medical School. This study was supported by U.S. Public Health Service Grant I-IL-5196. Requests for reprints should be addressed to Dr. Eve E. Slater, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114. Manuscript accepted August 14, 1975.
The clinical, roentgenologk and laboratory flndlngs In 124 patients wlth dksectkg aneurysm of the aorta are reported. In 53 patients the dlssectlon occurred ln the ascending aorta (“poxlmal” dlssectlon), and In 71 patient8 the site of orlgln was the descending thorack aorta (“dktal” dlssectlon). Certain dktkct clinical differences between the groups were apparent. Ahhough hypertension wa8 an important predkpo&g factor, R was slgnlflcantty more common In distal dtssectlon, as wpI atheroeclerosls. Back pain and hypertenston on hoapltal presentatkn cfraracterized patients wlth distal dksectkn. Conversety pattents wlth proximal dlssectlon were younger and had a slgnlfkantly hlgher Incidence of Marfan’s syndrome, cystk medial necroek, anterior chest pain, puke defklts, neurokglc compromke, &tk lnsufflclency and congestive heart failure. In both groups, syncope appeared to correlate well wlth the occurrence of cardiac tamponade. Chest roentgenograms almost always &owed an abnormal aortlc contour. Aortk angkgraphy, when performed, was usuatly confirmatory of the dlagnosk. Advances in the therapy of a disease require simultaneous advances in diagnosis, and this is surely true of dissecting aortic aneurysm. Since the introduction of surgical therapy by De Bakey et al. [l] in 1955 and medical treatment by Wheat et al. [2] in 1964, rapid identification and precise definition of dissecting aortic aneurysm have become mandatory. Historically, clinical recognition of%the disease has been slow in developing. Although originally described in 1761 by Morgagni [3] and officially named “aneurysme dissequant” by Laennec [4] in 1819. it was not until 1856 that antemortem diaonosis was first accomplished by Swaine and Latham [5]. Likewise, almost one century later, in 1950, in an extensive review of 735 cases published up to that time, correct antemortem diagnosis had been made in only 10.6 per cent of patients [6].
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TABLE
I
Sex, Age Range and Duration 124 Patients
of Disease in
Dissection
Men Women Age range (yr) Mean age (yrl Duration Acute (<2 wk) Subacute (2-6 wk) Chronic (>6 wk)
Proximal (N = 53)
Distal (N = 71)
36 17 19to75 55.4
54 17 42t0ai 62.0
41 1 11
55
MATERIAL AND METHODS The present series was gathered from a review of discharge summaries, surgical reports and autopsy records of the Massachusetts General Hospital for the period of time from January 1963 through December 1973. The composition of the series is largely clinical: 38 patients II
Predisposing Factors in 124 Patients with Dissecting Aortic Aneurysm Dissection
Cause Known hypertension* Evidence of prior hypertension Total with presumed hypertension* Marfan’s syndrome? Cystic medial necrosis’ Arteriosclerotic aorta’ No known predisposing factor
Proximal (N = 53)
0 istal (N = 71)
26 8 34 5 16 0 8
55 13 68 1 4 9 1
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Journal of Medlclne
surgery or to cardiac catheterization were excluded from this report. Classification was modified from that of De Bakey et al. [7], who identified three types of dissecting aneurysms on the basis of the site of origin and the extent. According to De Bakey’s classification, types I and II dissection begin in the ascending aorta, the intimal tear usually being located just above the sot-tic valve. Type I dissection extends for variable distances beyond the ascending aorta, whereas type II dissection is confined to the ascending aorta. In contrast, type Ill dissection originates distal to the arch vessels in the descending thoracic aorta, usually just beyond the origin of the left subclavian artery. Type Ill dissection may rarely progress in a retrograde fashion into the arch and ascending aorta. For the purposes of this review, because of their similar clinical behavior, types I and II will be referred to collectively as “proximal” dissection, and type Ill will be termed “distal” dissection. The duration of the disease was judged to be “acute” if present for less than two weeks prior to admission, “subacute” if present for two to six weeks, and “chronic” if present longer than six weeks. Patients with subacute and chronic dissection were included in the series only if adequate information relative to signs and symptoms was available on retrospective review of their records. RESULTS
Classification of Patients. Age and sex distribution for the 124 patients are presented in Table I. Men predominated in this series by a ratio of 2.7 to 1. Peak incidence was in the sixth and seventh decades, the mean age of patients with proximal disease being almost 10 years less than that of patients with distal disease. Distal dissection occurred more commonly than proximal dissection by a ratio of 1.3 to 1. Ninety-six patients (77 per cent) had acute dissection, seven patients (6 per cent) had subacute dissection, and 21 patients (17 per cent) presented with chronic disease.
l Denotes statistical significance between the two groups of P _< 0.01 when p values were calculated either by the chi square niethod and the Yates’continuity correction or by the Fischer’s Exact Test. ‘/’ Denotes p > 0.01 and p 20.05.
626
were seen in consultation by one of us (R.W.D.). An additional 52 cases were acquired from the angiographic files of the cardiac catheterization laboratory. Although most of these patients were included in the hospital discharge diagnostic category of “dissecting aortic aneurysm,” a further 15 cases were identified by reviewing this source. Seven further patients were obtained from the list of patients undergoing surgery for dissecting aneurysm. Finally, 12 cases were found in a search of our pathology files. Thus, of the 124 patients, 112 were identified from clinical sources, and only 12 from postmortem files. Patients with
iatrogenic dissection secondary to cannulation at cardiac
6 IO
Recognition of dissecting aortic aneurysm has increased over recent years because of more widespread appreciation of the disease and the advent of increasingly sophisticated diagnostic technics, most notably angiography. Thus accurate and prompt diagnosis should now be possible in well over 90 per cent of cases. Nonetheless, a high index of suspicion by the physician is still the single most important factor in making the diagnosis. To reexamine the clinical features of dissecting aortic aneurysm, we have reviewed the records of 124 patients, seen within the past 10 years at the Massachusetts General Hospital, in whom the diagnosis was established either by angiography, at surgery or on autopsy examination. Results of medical and surgical management of these patients will be presented in a subsequent report.
TABLE
DeSANCTlS
Volume
Table II reflects the predisPredisposing Factors. posing factors. There was a history of defin/te hypertension in 55 of 71 patients (78 per cent) with distal disease and in 26 of 53 patients (49 per cent) with proximal dissection. An additional 13 patients in the distal group and eight ,patients in the proximal group
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had evidence of prior hypertension as indicated by otherwise unexplained left ventricular hypertrophy seen on electrocardiogram or at autopsy. Thus 96 per cent of those with distal dissection and 64 per cent with proximal lesions had actual hypertension or evidence of prior hypertension; a highly significant difference between these two groups (p <0.0005) exists. Six patients (5 per cent) had overt Marfan’s syndrome, five with proximal lesions. The sixth patient, aged 51 years, who presented with a history of typical pain one year prior to admission and progressive symptoms of congestive heart failure, was found to have a dissection beginning at the left subclavian artery without retrograde extension. His aortic root and sinuses of Valsalva were strikingly dilated, but the upper half of the ascending aorta and aortic arch were of normal caliber. In addition, 20 patients (16 per cent) without clinical evidence of Marfan’s syndrome were found to have cystic medial necrosis on histologic examination of the aorta. In 14 of these 20 patients, a history of hypertension was also extant. Six patients had cystic medial necrosis and proximal dissection without apparent preexisting hypertension. Among these were five patients in whom aortic valvular disease and cystic medial necrosis appeared to coexist with proximal dissection. In two patients, aged 37 and 43 years, neither with a history of hypertension or Marfan’s syndrome, a bicuspid aortic valve, cystic medial necrosis and proximal dissection were confirmed at autopsy. In three patients, aged 5 1, 56 and 60 years, cardiac catheterization supported evidence of the combined lesion which was confirmed at surgery. The sixth patient with cystic medial necrosis and without hypertension was a 34 year old man who had experienced protracted industrial exposure to dimethylhydrazine ((CH&-N-NH*). Nine patients had evidence of a dissection within an atherosclerotic aorta. All nine had distal disease, and eight were hypertensive. In only one patient could a history of recent and severe chest trauma be elicited, and this patient had coexistent cystic medial degeneration. Likewise, in only 17 of the 124 patients (14 per cent) could a his-
tory of possibly relevant excitement or effort be linked to the actual onset of pain. These included such diverse activities as heavy lifting, leaning on a pneumatic drill, bowling, straining at stoof and tension during a court trial. No patient in this series had aortic dissection related to pregnancy, although our hospital does not provide obstetrical service. Nine patients (7 per cent) in the current series had no identifiable predisposing factor.
TABLE f II
DeSANCTlS
Presenting Symptoms Dissection
Symptom --Pain Pain alone Pain with syncope Pain with congestive heart failure Pain with cerebrovascular accident Congestive heart failure without pain Cerebrovascular accident without pain Abnormal chest roentgenogram without pain
Proximal (N = 53)
Distal (N = 71)
47
69
37 4
66 2
4
1
2
0 4
0
2
0
0
2
Presenting Symptoms. The presenting symptoms of the 124 patients are summarized in Table Ill. Severe pain of acute onset occurred as a presenting symptom in 116 of the 124 patients (94 per cent). Other less common but previously recognized presenting symptoms included syncope, stroke and congestive heart failure with or without associated chest pain. Among the patients with congestive heart failure, all eight with proximal disease had aortic insufficiency to account for their left ventricular decompensation. The one patient with congestive failure and distal dissection has previously been described as having Marfan’s syndrome with aortic regurgitation secondary to annuloaortic ectasia. Six patients (5 per cent) presented with painless dissection. Two patients, both with distal disease, had asymptomatic widening of the aortic arch, and in four patients with proximal disease, dissecting aneurysms were discovered at surgery for severe aortic valve regurgitation. The location of pain as it occurred in proximal and distal disease is summarized in Tables IV and V, in which pain has been categorized both with respect to the site of major pain (Table IV) as well as the sites of any pain (Table V). A significantly larger number of patients with proximal dissection experienced the major site of pain in the anterior chest. Conversely, the posterior chest, usually the interscapular area, was the site of major pain significantly more often in distal dissection. When all the sites of pain (rather than just the major pain) are considered, half of the patients with proximal disease had only anterior chest pain, in contrast to only 6 per cent of those with distal disease. Although 36 per cent of patients with distal dissection had isolated posterior pain as opposed to only 10 per cent of patients with proximal lesions, 65 of 69 (94 per cent) with distal dissection reported the presence of at least some back pain.
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The pain was migratory in 82 of the patients with pain (71 per cent), and the path of migration often, although not invariably, corresponded to the path of aortic vessels involved in the dissection process. Pain in the jaw and throat was somewhat more common in proximal dissection. Low back pain was experienced in both groups although with higher frequency in those with distal dissection. Physical Findings. A summary of the pertinent physical findings is contained in Table VI. Forty patients with distal dissection (56 per cent) were hypertensive when initially seen, as opposed to only five (9 per cent) with proximal dissection. In contrast, only one patient with distal dissection was hypotensive as opposed to 12 with proximal dissection. Of these 12 patients, five had cardiac tamponade, three had intrapleural or intraperitoneal rupture, and four had extensive dissection involving the brachiocephalic vessels. Pulse deficits, which included either absence or a clear-cut diminution of a pulse, were found in approximately one half of the patients with proximal disease, and predictably, the brachiocephalic vessels were most frequently compromised. Pulse deficits were significantly less common in patients with
distal dissection and tended to involve the left subclavian and femoral vessels, although these vessels were about equally affected by the distal propagation of dissections originating proximally. The one patient with distal disease and right subclavian compromise had evidence of retrograde dissection to the aortic root. In no case of distal dissection was a carotid pulse deficit recorded.
TABLE IV
Relationship of Site of Major Pain to Origin of Dissection in Patients Presenting with Pain
-
TABLE VI
Dissection Site of Major Pain
-
Chest, anterior* Chest, posterior* Chest, both anterior and posterior Neck and throat Abdomen Suprapubic l
A pulsatile sternoclavicular joint was noted in one patient with proximal dissection. The murmur of aortic regurgitation was heard in 36 patients with proximal disease (68 per cent) and in four patients with distal disease (6 per cent), three of whom were known to have had prior aortic regurgitation. In two of these four patients, the murmur was due to long-standing and severe hypertensive disease. The third patient had Marfan’s syndrome with annuloaortic ectasia. Retrograde dissection accounted for the murmur in the fourth patient. Neurologic deficits predominated in patients with proximal disease. These deficits included cerebrovascular accidents, ischemic paraparesis, ischemic peripheral neuropathy and disturbances of consciousness. In this series, hemiparesis and coma were seen only in patients with proximal dissection, and the neurologic compromise of distal disease involved only the lower extremities. Miscellaneous Complications. No patient had symptoms specifically referable to mesenteric infarc-
Distal (N = 69)
31 (65%) 5 (10%)
19 (27%) 39 (57%)
4 4 3 0
Denotes statistical significance
TABLE V
Proximal (N = 47)
Two Groups Dissection
8 0 2 1
(p _< 0.01).
Dissection
Anterior only” Posterior only* Anterior and posterior Total with any pain in back* Jaw and throatt Low back
Proximal (N = 47)
Distal (N =‘69)
23 5 19 23 12 6
4 25 20 65 7 13
(50%) (10%) (40%) (50%) (26%) (13%)
(6%) (36%) (57%) (94%) (10%) f21%)
* Denotes statistical significance of p < 0.01, Denotes p > 0.01 and p 5 0.05.
Hypertension (blood pressure > 150/90 mm Hg bilaterally)* Hypotension (blood pressure Q 100 mm Hg bilaterally)* Pulse deficit Total patients with deficit* Total pulse deficits* Right carotid Right subclavian Left carotid Left subclavian Right femoral Left femoral Pulsatile sternoclavicular joint Murmur of aortic regurgitation* Neurologic manifestations Total patients with neurologic manifestations* Cerebrovascular accident lschemic peripheral neuropathy lschemic spinal cord damage Coma, altered consciousness l
Denotes statistical significance
t
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Proximal (N = 53)
Physical Finding
Relationship of Location of Any Pain to Site of Origin of Dissection
Site of Any Pain
Pertinent Physical Findings in the
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fp I
Distal -
(N = 71) 40
5 12
1
27 43
11 14 0 1 0 3 3 7
10 11 1 8 8 5 1 36
0 4
19 7 6 1 5 0.01).
4 0 2 2 0
CLINICAL
RECOGNITION OF DISSECTING AORTIC ANEURYSM-SLATER.
tion, although one patient had autopsy-proved superior mesenteric dissection. She was obtunded on presentation and had evidence of right carotid, right coronary and right renal artery occlusion as well. Three patients presented with oliguria. In only one was this related to bilateral renal infarction. Two others had acute tubular necrosis. Ten additional patients had evidence of unilateral renal arterial involvement by the dissection at autopsy. Six had proximal dissection and four had distal dissection. One patient experienced hemoptysis. Hemorrhagic pleural effusion was recorded at the time of presentation in 11 patients, nine with distal dissection and two with proximal dissection. Ten patients had leftsided effusion and one had bilateral effusions. Horner’s syndrome was observed in one patient with proximal disease. Three patients had evidence of acute myocardial infarction on electrocardiogram. Two had proximal and one had distal dissection; all three died. Subsequent autopsy confirmed dissection of the right coronary artery in two patients: in the third patient, postmortem examination was not performed. His electrocardiographic changes were in the anterior precor-
dial leads. Other Laboratory Studies. Pertinent laboratory information is presehted in Table VII. A small number of patients presented with hematocrit values less than 30 per cent, and almost two-thirds of the paTABLE VII
Laboratory Studies in Patients with Dissecting Aneurysm*
Anemia Leukocytosis Elevated SGOT level Elevated LDH level Elevated bilirubin level
16/105 55/89 6/75 42173 13/66
115%) (62%) (8%) (58%) (20%)
* Numerator indicates the number of patients with the abnormality and the denominator indicates the number of patients with results available for interpretation,
TABLE VIII
DeSANCTlS
tients had a polymorphonuclear leukocytosis at the onset of their disease. Serum glutamic oxaloacetic transaminase (SGOT) values were usually within normal limits, but lactic dehydrogenase (LDH) and bilirubin levels were more often elevated. The electrocardiographic abnormalities in the 120 patients with an electrocardiogram available for analysis are summarized in Table VIII. Notable are the relative paucity of acute ischemic changes and the high frequency of left ventricular hypertrophy with strain pattern. Roentgenographic Findings. The roentgenographic findings are recorded in Table IX. In 85 per cent of patients in the current series, an abnormal chest roentgenogram suggestive of the diagnosis was found either initially or in retrospect. These abnormalities included (1) an abnormal aortic contour, (2) a wide superior mediastinum and (3) the “calcium” sign, a pathognomonic separation of aortic wall ‘intimal calcification from the outer margin of the aorta which occurred in 10 of the 71 patients (14 per cent) with distal disease. Of the 124 patients, angiography was performed in 103-39 with proximal disease (74 per cent) and 64 with distal disease (90 per cent). In 38 of the 39 patients with proximal lesions and in all the 64 patients with distal dissection who underwent angiography, diagnosis was confirmed by this technic. In all but four patients with proximal disease, a definite or probable site of origin of the dissection could be identified. Angiography was attempted but was unsuccessful in two patients with distal disease because of tortuous aortic vessels. Only one major complication of angiography occurred, and that was in a patient who sustained right ventricular perforation with cardiac tamponade which was successfully treated. COMMENTS Effective therapy for dissecting aortic aneurysm mandates the need for early and accurate diagnosis of this entity. Several features emerge from our
Electrocardiographic Findings Dissection
Electrocardiographic Abnormalities
Proximal (N = 50)
Distal (N = 70)
Normal Left ventricular hypertrophy Old myocardial infarction New myocardial Infarction Bundle branch block S-T + T wave abnormalities Electrical alternans Low voltage
15 21 5 2 2 10 1 1
17 30 10 1 6 9 0 0
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TABLE IX --
Roentgenographic Findings Dissection
Abnormalities on Chest Roentgenogram
Proximal (N = 45)
Definitely abnormal aortic contour “Possibly” abnormal aorta Normal chest roentgenogram “Calcium” sign Pleural effusion
34 8 3 0 2
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Distal (N = 71) _____
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study and from past reports that may be helpful in suggesting the diagnosis and predicting the site of origin of the dissection. As in other series, we found that this disease affects men more frequently than women, with a peak incidence in the sixth and seventh decades [8]. The predominance of distal dissection over promixal dissection in the patients we studied contrasts with the experience of others, most notably the extensive review of Hirst et al. [8], in which approximately 60 per cent of 505 cases occurred in the ascending aorta. Two factors likely account for this difference, and both relate to the fact that dissecting aneurysms that occur in the ascending aorta are more lethal than distal dissections. First, ours was largely a clinical series, whereas that of Hirst et al. was based on postmortem examination. Second, we serve as a referral hospital for patients with dissecting aneurysm, and those with distal dissection are more likely to survive long enough to be transferred to our hospital for ther-
By far the most common symptom of dissecting aneurysm is pain, which is almost universally present unless loss of consciousness accompanies the dissection. Severe pain was present in 94 per cent of the patients we studied. Although not specifically analyzed in this report, the patients’ descriptions of the pain were frequently peculiarly appropriate to the actual event. Terms such as “tearing” or “ripping” were often noted. Migration of the pain from the initial location as the dissection extends to other sites, as occurred in almost three quarters of our patients, is common and affords an important clue to the diagnosis of dissecting aneurysm. In contrast with the findings of Lindsay and Hurst [9], but in agreement with those of Burchell [13], our experience would also indicate that the location of pain may be of some help in suggesting the site of origin of the dissection. Pain that was exclusively in the anterior portion of the chest was significantly more frequent with proximal dissection, whereas pain that was exclusively posterior was significantly more common with distal dissection. Pain felt simultaneously anteriorly and posteriorly can be present with either a proximal or distal dissection. However, the absence of back pain strongly mitigates against a dissection originating in the descending thoracic aorta, as it was present in 94 per cent of patients with distal dissection. Although very rare, dissecting aneurysm can occur painlessly [ 141. The occurrence of syncope in aortic dissection may bear a special significance. Syncope without focal neurologic signs occurred in six of the 124 cases studied. In five cases, the patients were subsequently found tu have rupture of the dissection into the pericardial cavity with cardiac tamponade. The sixth patient died at cardiac catheterization before the presence of pericardial fluid could be demonstrated, but cardiac tamponade had been suspected clinically. Congestive heart failure, when present, is usually a feature of proximal dissection, and it is almost invariably due to free aortic regurgitation. Sometimes the congestive failure may mask the presence of aortic regurgitation. In one patient in this series, dissecting aneurysm was suspected clinically and the patient was in profound congestive heart failure, but no murmur of aortic regurgitation could be heard. The presence of disproportionately bounding pulses in the face of severe congestive heart failure suggested that aortic incompetence was present, and this was indeed confirmed by subsequent angiography and surgery. The diagnosis of dissecting aortic aneurysm can often be made with reasonable assurance from the physical examination alone. It has been observed‘by several investigators that patients with dissecting an-
apy. Regarding etiology, hypertension was again confirmed as an extremely important factor, and significantly more so in distal than in proximal dissection. This coincides with the experience of Lindsay and Hurst [ 91. Six patients had Marfan’s syndrome and 20 patients had pathologic evidence of cystic medial necrosis. Of interest are the five adults in this report who presented with the triad of cystic medial necrosis, aortic valve disease and proximal dissection in the absence of any hypertension, Marfan’s syndrome or other underlying cause. This association has been previously noted by Core and Seiwart [ 101 and McKusick et al. [ Ill. The question of the relationship of environmental exposure to the development of cystic medial necrosis is raised because of the one patient in this series who exhibited that pathologic entity and who had a history of industrial exposure to dimethylhydrazine. Experimentally, it has long been known that cystic medial necrosis and aneurysmal dilatation with dissection of the aorta can be induced in rats fed a diet containing a large amount of Lathyrus odoratus (sweet pea) [ 121. The active principle is believed to be aminopropionitrile (HsN-CH2-CH2-CN). Although chemically unrelated to aminopropionitrile, dimethylhydrazine ((CH&N-NH2) has also been shown to adversely affect collagen metabolism experimentally (personal communication, Dr. M. V. Barrow, September 12, 1972). It is unclear whether arteriosclerosis alone predisposes to dissection [8]. Nine of the patients we studied had an intimal tear occurring within an arteriosclerotic aorta. lt would seem likely that the arteriosclerosis was contributory rather than coincidental.
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FIgwe 1. Mechanisms of aortic regurgitation in dissecting aortic aneurysm. A, circumferential tear with widening of aortic root and separation of the aortic cusps, B, displacement of one aortic cusp substantMly below the level of the others by the pressure of the dissecting hematoma, C, actual disruption of the annular leaflet support leading to a flail cusp.
eurysm appear to be in shock, yet the blood pressure may actually be elevated when it is measured [9,13,14]. This was true in our experience, especially with distal dissection. Differences in arm blood pressures and the finding of absent or reduced arterial pulses are key diagnostic clues. Pulses may be lost either by direct compression of the lumen of the artery by extension of the dissection into it, or by an intimal flap that blocks the orifice of the vessel. Pulse loss may be transitory. Restoration of pulses may be achieved by reentry locally into the artery itself, distally into the aorta, thereby decompressing the false lumen, or by movement of the intimal flap away from the orifice. Deficits involving the brachiocephalic vessels were found almost exclusively in proximal dissection, although both proximal and distal dissections may extend far enough peripherally to occlude the femoral arteries. The development of new aortic insufficiency in a patient with chest pain is an important clue to the presence of proximal dissection and was present in two-thirds of our cases. Aortic incompetence in dissecting aortic aneurysm may be produced by three mechanisms (Figure 1). First, the dissection may dilate the root of the aorta, widening the annulus and making it impossible for the leaflets to coapt in diastole. Second, with an asymmetric dissection, the pressure of the dissecting column against the aortic root may depress one leaflet substantially below the level of the others, thus rendering the valve incompetent. Third, the annular support of the leaflets or the leaflets themselves may be torn such that they are unable to support the column of blood in the aorta in diastole. The mechanism of aortic incompetence is
of some relevance in regard to surgical therapy. When aortic insufficiency is produced by elther of the first two mechanisms, simple decompression of the aorta by surgically excising the intimal tear and occluding the false lumen may result in resuspension of the aortic leaflets such as to restore competence. However, if the annular support is disrupted, the aortic valve will very likely have to be replaced at the time of operation. Although not common, neurologic deficits are important sequelae of dissecting aneurysm and may be presenting symptoms. The neurologic deficits of dissecting aortic aneurysm have been summarized by Weisman and Adams [ 161 and are of three types. First, cerebrovascular accident secondary to occlusion of the arteries supplying the brain may occur, and this is much more frequent wlth proximal dissection. Second, ischemic neuropathy may result from the blockage of a peripheral artery, particularly the femoral arteries, and may occur by the distal extension of either a proximal or distal dissection. Third, the spinal cord may be subjected to ischemic damage as a result of severing particularly the intercostal arteries, which are the major suppliers of blood to the spinal cord. A pulsatile sternoclavicular joint, described by Logue and Sikes [ 171 as a clue to the diagnosis of dissection of the ascending aorta, was noted in one of the patients studied. Many additional phenomena may result from dissecting aneurysm as a consequence or compression of surrounding structures by a dilated aorta, by occlusion of any artery arising from the aorta, or by perforation and hemorrhage of the dissection. Thus, three
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of the patients with proximal dissection had acute myocardial infarction from compressive occlusion of a coronary artery. Occlusion of the renal arteries may cause renal infarction, and dissection into the arteries supplying the mesenteric vascular bed can result in mesenteric infarction. One of the patients with proximal dissection had Horner’s syndrome from pressure against a cervical sympathetic ganglion. Other reported manifestations not encountered in our series are left recurrent laryngeal nerve pressure resulting in vocal cord paralysis and hoarseness, superior mediastinal syndrome, pulsating neck masses [8], hemorrhage into the tracheobronchial tree, and extension of a proximal dissection into the atrial septum and atrioventricular conduction system causing heart block [ 181. Except for chest roentgenography and aortic angiography, the laboratory is not of great help in making the diagnosis of dissecting aneurysm. The electrocardiogram is useful in a negative sense, that is, failing to show evidence of myocardial infarction in a patient whose history might suggest one. Left ventricular hypertrophy is common, reflecting prior hypertension. An elevated LDH level is frequent, and presumably reflects hemolysis of blood in the false channel. Hemolysis may also elevate the serum bilirubin level. Leukocytosis is usually present in the patient who presents shortly after the onset of pain, and anemia may result from leakage of the dissecting aneurysm. Chest roentgenography is very important because the aortic contour is usually abnormally widened, as was the case in 85 per cent of the patients studied. A localized bulge in the aorta may suggest the site of origin of the dissection [ 191. Wide separation of intimal calcification from the outer border of the aortic knob (present in 14 per cent of the patients with distal dissection) is virtually pathognomonic if the aortic knob is calcified. A left pleural effusion was present in 9 per cent of the patients, the majority of whom had distal dissection. Although often hemorrhagic, pleural effusions may accumulate simply as a result of exudation around the dissection.
DeSANCTIS
The great advance in the diagnosis of dissecting aneurysm has, of course, been contrast angiography. Although we originally performed it by injection of dye into the pulmonary artery and opacification of the aorta in the venous phase, we have increasingly shifted over to retrograde aortic procedures as the hazards of this approach have proved to be minimal. The site of origin of the dissection can often be accurately pinpointed, which is an important consideration if surgery is to be undertaken. On the other hand, as Shuford et al. [20] have pointed out, angiography is not foolproof, and a number of pitfalls may occur in diagnosing dissection of the aorta. These include such problems as faint opacification of the false lumen, unusual tearing of the intima, and equal simultaneous opacification of both channels. Recent correlations of angiography with survival from aortic angiography suggest a better prognosis in patients with nonopacified false channels [21]. Those without false lumen filling had both a better survival rate and a lesser incidence of subsequent localized aneurysm formation than.patients with angiographic filling of false channels. In addition to trying to define the site of origin and the extent of the dissection, angiography of the distal circulation is desirable, especially if surgery is contemplated. For example, either or both renal arteries or a major mesenteric vessel may be fed from the false channel, and surgical obliteration of the false lumen can compromise the circulation of vital organs perfused from it. Although none of the patients in this series was studied with echocardiography prior to December 1973, it should be noted that this technic has recently been reported to be of value in the diagnosis of proximal dissection [ 22-241. Despite all technical advances, however, it is worth emphasizing again that the single most important factor in diagnosing dissecting aortic aneurysm is a strong index of suspicion on the part of the physician .
REFERENCES 1.
2.
3.
4.
5.
632
DeBakey ME, Cooiey DA, Creech 0 Jr: Surgical considerations of dissecting aneurysm of the aorta. Ann Surg 142: 586, 1955. Wheat MW Jr, Palmer RF, Bartfey TD. Seeiman RC: Treatment of dissecting aneurysms of the aorta without surgery. J Thorac Cardiivasc Surg 50: 364, 1964. Morgagni GB: DeSedibus et Causis Morborum per Anatomen indagatis Libri Quinque. Venetiis. ex Typog Remondiufana, 1761. Laennec RTH: De I’Auscultation Mediate, ou Traite du Diagnostic des Maladies des Poumons et du Coeur, voi 1, Paris, Cher J-A Brossand, et J-S Chaude, 1819, p 411. Swaine K, Latham PM: A case of dissecting aneurysm of
May 10, 1976
The American Journal of Medicine
6.
7.
8.
9.
Volume 60
the aorta. Trans Path Sot London 7: 106. 1855-1856. Levinson DC, Edmeades DT, Griffith GC: Dissecting aneurysm of aorta: its clinical, electrocardiographic, and iaboratory features: report of 58 autopsied cases. Circulation 1: 360. 1950. DeBakey ME, Heniy WS, Cooiey DA, Crawford ES, Beaii AC: Surgical management of dissecting aneurysms of the aorta. J Thorac Cardiovasc Surg 49: 130, 1965. Hirst AE Jr, Johns VJ Jr, Kime SW Jr: Dissecting aneurysm of the aorta: a review of 505 cases. Medicine 37: 217. 1958. Lindsay J Jr, Hurst JW: Clinical features and prognosis in dissecting aneurysm of the aorta. A m-appraisal. Circu-
CLINICAL RECOGNITION OF DISSECTING AORTIC ANEURYSM-SLATER. DeSANCTlS
10. 11,
12.
13.
14. 15.
16. 17.
lation 35: 880, 1987. Gore I, Seiwart VJ: Dissecting aneurysm of the aorta: pathologic aspects. Arch Pathol 53: 12 1, 1952. McKusick VA, Logue RB, Bahnson HT: Association of aortic valvular disease and cystic mediil necrosis of the ascending aorta: report of four instances. Circulation 16: 188,1957. Ponseti IV, Baird WA: Scoliosis and dissecting aneurysm of the aorta in rats fed with Lathyrus cdoratus seeds. Am J Pathol 28: 1059, 1952. Burchell HB: Aortic dissection (dissecting hematoma; dissecting aneurysm of the aorta). Circulation 12: 1068, 1955. Cohen S, Liimann D: Painless dissecting aneurysm of the aorta. N Enal J Med 271: 143, 1964. Anagnostopoios CE, Prabhakar MI, Kiile CF: Aortic df sections and dissecting aneurysms. Am J Cardiil 30: 263, 1972. Weisman AD, Adams RD: Neurological complications of dissecting aortic aneurysm. Brain 67: 69. 1944. Logue RB, Sikes C: New sign in dissecting aneurysm of the aorta; pulsation of sternoclavicutar joint. JAMA 148: 1209, 1952.
18.
19.
20.
21.
22.
23.
24.
May lo,1976
Yacoub MH, Schottenfeld M, Kittle CF: Hematoma of the interatrial septum with heart block secondary to dissecting aneurysm of the aorta. A clinicopathologic entity. Circulation 46: 537, 1972. Lodwick GS: Dissecting aneurysms of the thoracic and abdominal aorta: report of 6 cases, with a discussion of roentgenologic findings and pathologic changes. Am J Roentgen01 69: 907, 1953. Shuford WH, Sybers RG, Weens HS: Problems in the aortographic diagnosis of dissecting aneurysms of the aorta. N Engl J Med 280: 225, 1969. McFarland J, Willerson JT, Dinsmore RE, Austen WG, Buckley MJ, Sanders CA, DeSanctis RW: The medical treatment of dissecting aortic aneurysms. N Engl J Med 286: 115, 1972. Nanda NC, Gramiak R, Shah PM: Diagnosis of aortic root dissection by echocardiography. Circulation 48: 506, 1973. Moothart RW, Spangler RD, Blount SG Jr: Echocardiography in aortic root dissection and dilatation. Am J Cardiol 36: 11, 1975. Brown OR, Popp RL, Kloster FE: Echocardiographic criteria for aortic root dissection. Am J Cardio136: 17, 1975.
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