Ann Thorac Surg 2004;78:321-323
© 2004 The Society of Thoracic Surgeons
Case report
Nontraumatic localized dehiscence of the proximal ascending aorta through an aortic valve commissure
Andrew E. Newcomb, MBBSa*,
Michael A. Rowland, FRACSa
a Department of Cardiothoracic Surgery, Alfred Hospital, Melbourne, Victoria, Australia
Accepted for publication April 14, 2003.
* Address reprint requests to Dr Newcomb, Department of Cardiothoracic Surgery, Alfred Hospital, Commercial Rd, Melbourne, Victoria 3004, Australia
e-mail: a.newcomb{at}alfred.org.au
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Abstract
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Acute dissection of the ascending aorta is a life-threatening condition that requires timely recognition and management. Here we describe an unusual variant of acute dissection involving a localized tear in the proximal ascending aorta through the commissure of the left and noncoronary cusps of the aortic valve causing aortic regurgitation.
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Introduction
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The incidence of acute dissection is unknown because many clinical cases are not correctly diagnosed [1]. Timely recognition and management are paramount. This case report describes an unusual variant of this often life-threatening condition.
A 74-year-old man was admitted to a general hospital with a 4-week history of worsening dyspnea and exercise tolerance, having been previously well. He had a history of hypertension and was an ex-smoker. On initial examination he was normotensive and was noted to have a new early diastolic murmur of aortic incompetence, as well as an ejection systolic murmur. Electrocardiography revealed that he was in sinus tachycardia at 96 beats per minute. There were no acute ischemic changes and there was evidence of mild left ventricular hypertrophy. Chest roentgenogram revealed bilateral pleural effusions with no cardiomegaly. Transthoracic echocardiography (TTE) revealed severe aortic regurgitation with a normal looking aortic valve. Contrast enhanced computed tomography (CT) revealed no evidence of aortic dissection. A transesophageal echocardiogram (TEE) was performed to assess for evidence of aortic dissection as a cause for the new murmur. This illustrateed the aortic valve to have normal morphology with a dissection flap evident in the proximal ascending aorta "not far from the aortic valve."
He was transferred to our institution for definitive care. He arrived in a stable condition and was transferred to the operating theater where an extensive TEE examination was performed by two experienced ultrasonographers. This examination confirmed the suspicion of a normal ascending aorta with a nonpropagating dissection inferior to the origin of the left main coronary artery (Fig 1).
This was associated with avulsion of the commissure between the left and noncoronary aortic valve leaflets, and is demonstrated by the operative photograph in Figure 2
and the schematic illustration in Figure 3.
The valve leaflets and the aorta were histologically normal. Repair was undertaken to the area of intimal disruption, as this was felt likely to be the primary lesion and a potential substrate for extended dissection if not secured. Attention was then turned to the aortic valve mechanism with resuspension of the commissure to its previous position using Teflon pledgeted polypropylene sutures (DuPont Pharmaceuticals, Wilmington, DE), however on partial wean from bypass it was evident that there was still mild to moderate central aortic regurgitation. Due to the patient's age and a desire to minimize cardiopulmonary bypass times the valve was then excised and replaced with a 21-mm porcine bioprosthesis. The patient's recovery was uneventful and he was discharged home 5 days after his operation.
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Fig 2. (Left) Operative photograph and (right) sketch of the valve at the time of surgery from the head of the bed. Sketch simplified to highlight the region of the tear through the commissure, and the position of the commissure. The region of the tear has thick crosshatching, while the commissure has thin horizontal crosshatching.
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Fig 3. Schematic illustration of the aorta opened longitudinally to indicate where the tear was located.
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Comment
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Myxomatous degeneration, trauma, infective endocarditis, annuloaortic ectasia, rheumatic fever, fenestrated or bicuspid aortic valves, syphilis, and type A aortic dissection may all cause aortic regurgitation [2]. The mechanisms by which type A aortic dissection cause aortic regurgitation have been described by Movsowitz and colleagues [3]. This variant of a localized dehiscence of the proximal ascending aorta through a commissure of the aortic valve is rare, being reported in only three recent reports [2, 4, 5]. The four cases in those three reports had various etiologies for the commissural tears. The first two cases [2] were patients in whom the commissures separated completely from the aortic wall, one due to hypertension, and the other with no obvious cause. The other Japanese case [4] involved a localized layer dehiscence in the aortic wall around the commissure between the right and noncoronary cusps. This was due to massive hypertension. The final case [5] consisted of detachment of a complete commissure in an aneurysmal aorta with cystic medial necrosis. Our patient's history of hypertension was the only precipitating factor that was identified, although he was not hypertensive at presentation.
Typical features associated with aortic valve rupture would be onset of heart failure, and the development of a new or worsening murmur of aortic regurgitation. This condition may progress to death if left untreated, so prompt surgical intervention is essential.
In addition to clinical suspicion, a number of investigations are available to clinicians to assist in diagnosis of this condition. Moore and associates [6] compared some of these different modalities, and found that CT and TEE had similar sensitivities for detection of type A dissections. These are both readily available and commonly used together. The diagnosis in our patient was not made until the TEE was performed several days after his initial presentation. This was pursued because of the initial clinical suspicion despite negative findings of other investigations. Sherwood and Gill [7] advocate this type of aggressive approach when dealing with the diagnosis of this condition, even to the point of repeating investigations to establish a diagnosis.
Surgical intervention in this setting could have included repair and resuspension of the valve, or replacement, with or without replacement of the ascending aorta. In this particular case, the integrity of the aortic wall outside the area of interest was adequate, so we initially attempted repair of the valve without any intervention to the ascending aorta. After the initial repair was found to be unsuccessful, we elected to replace the valve for the reasons outlined above. We again did not attempt replacement of the ascending aorta because it was felt to be structurally sound, and this was a localized process.
This case highlights an unusual and potentially life-threatening cause of aortic regurgitation and the importance of pursuing the diagnosis in the face of negative investigation findings. It also serves to emphasize the complementary roles of CT, TTE, and TEE, as well as highlighting their areas of weakness.
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References
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- Pate J.W., Richardson R.L., Eastridge C.E. Acute aortic dissection. Am Surg 1976;42:395.[Medline]
- Aoyagi S., Fukunaga S., Oishi K. Aortic regurgitation due to non-traumatic rupture of the aortic valve commissures: report of two cases. J Heart Valve Dis 1995;4:99-102.[Medline]
- Movsowitz H.D., Levine R.A., Hilgenberg A.D., Isselbacher E.M. Transesophageal echocardiographic description of the mechanisms of aortic regurgitation in type A aortic dissection: implications for aortic valve repair. J Am Coll Cardiol 2000;36:884-890.[Abstract/Free Full Text]
- Sakakibara Y., Gomi S., Mihara W., Mitsui T., Unno H., Doi T. Acute heart failure due to local dehiscence of aortic wall at aortic valvular commissure. Jpn J Thorac Cardiovasc Surg 2000;48:80-82.[Medline]
- Kupersmith A.C., Belkin R.N., McClung J.A., Moggio R.A. Aortic valve commissural tear mimicking type A aortic dissection. J Am Soc Echocardiogr 2002;15:658-660.[Medline]
- Moore A.G., Eagle K.A., Bruckman D., et al. Choice of computed tomography, transesophageal echocardiography, magnetic resonance imaging, and aortography in acute aortic dissection: International Registry of Acute Aortic Dissection (IRAD). J Am Coll Cardiol 2002;89:1235-1238.
- Sherwood J.T., Gill I.S. Missed acute ascending aortic dissection. J Card Surg 2001;16:86-88.[Medline]
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Abstract
Introduction
