Ann Thorac Surg 1995;59:1017-1019
© 1995 The Society of Thoracic Surgeons
Case Reports
Aortic Dissection: Rupture Into Right Ventricle and Right Pulmonary Artery
Laurence N. Spier, MD,
Michael H. Hall, MD,
Roy L. Nelson, MD,
Vincent A. Parnell, MD,
Gustave J. Pogo, MD,
Anthony J. Tortolani, MD
North Shore University Hospital, Manhasset, New York
Accepted for publication August 12, 1994.
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Abstract
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Rupture of an acute ascending aortic dissection into a surrounding cardiac chamber or pulmonary artery is an uncommon occurrence, and is often only diagnosed post mortem. Although fistulization (aortopulmonary and aorta--right atrial) after acute aortic dissection has been well documented in the literature, acute aortic dissection fistulizing into both the right ventricle and pulmonary artery has not. We report on a 75-year-old woman who presented with an acute ascending aortic dissection with both aortopulmonary and aorta--right ventricular fistulas who underwent repair and had long-term survival.
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Introduction
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Acute aortic dissection, commonly seen in patients with chronic hypertension, is caused by an intimal tear in the aorta that results in blood tracking through the media. The false channel that forms can then reenter the aortic lumen and progress retrogradely, causing occlusion of the coronary arteries and aortic insufficiency, or it can proceed antegradely and occlude the head vessels and other branches of the aorta, leading to neurologic and other ischemic complications. The dissection can also rupture through the adventitia of the aorta, leading to cardiac tamponade or hemothorax. Although rare, the dissection can cause a fistula to form between the aorta and other anatomic structures in the area (ie, pulmonary artery and cardiac chamber), resulting in a left-to-right shunt. Several such cases have been reported, including aortopulmonary, aorta--right atrial, and aorta--right ventricular fistulas. We have encountered a case of an acute ascending aortic dissection rupturing into two different structures, causing both aortopulmonary and aorta--right ventricular fistulas.
A 75-year-old woman with a medical history significant only for hypertension presented to the North Shore University Hospital emergency room with complaints of chest pain and shortness of breath. Upon admission, the patient underwent electrocardiography that revealed a sinus tachycardia of 130 beats/min with no ST or T wave changes. An admission chest x-ray study revealed the presence of congestive heart failure and bilateral effusions. The patient was admitted to the medical intensive care unit so that she could be watched for possible myocardial infarction. The patient subsequently underwent Doppler echocardiography that revealed a linear echogenic density in the ascending aorta with flow, a finding suggesting the presence of aortic dissection. Mild mitral regurgitation with normal left ventricular function was also documented. The patient subsequently underwent magnetic resonance imaging that revealed no evidence of aortic dissection. Because we continued to suspect a diagnosis of aortic dissection, the patient underwent aortography, which revealed a large left-to-right shunt located predominantly at the level of the pulmonary artery and showing signs consistent with rupture of an aneurysm of the sinus of Valsalva. A resultant left-to-right shunt causing overcirculation of the lung was also noted. Cardiac catheterization revealed a severe right-sided pressure elevation: right atrium, 26 mm Hg; right ventricle, 61/37 mm Hg; pulmonary artery, 63/37 mm Hg; pulmonary capillary wedge pressure, 39 mm Hg; and shunt ratio, 3:1. Cardiac catheterization also documented severe diastolic left ventricular dysfunction, a normal left coronary artery system, and a right coronary artery that was only faintly visualized. No aortic insufficiency was appreciated.
A ruptured aneurysm of the sinus of Valsalva was diagnosed, and the patient was taken to the operating room. After median sternotomy, the right ventricle was noticed to be distended and an obvious hematoma was found along the length of the ascending aorta and between the aorta and pulmonary artery, making the diagnosis of aortic dissection a possibility. The femoral artery was therefore cannulated for cardiopulmonary bypass. After separate cannulas were inserted into the superior and inferior venae cavae, the patient was placed on cardiopulmonary bypass. After systemic cooling, aortic cross-clamping, and the administration of cold blood cardioplegia, we evaluated the aorta and found an aortic dissection with the false lumen extending down into the right coronary sinus. The right coronary artery was noted to be completely disrupted off the sinus. Also apparent was the fistulization of the aorta into both the right ventricle and the main pulmonary artery at separate points (Fig 1
). The pulmonary artery fistula was repaired with interrupted 4-0 pledgeted Prolene suture (Ethicon, Somerville, NJ). After the aortic leaflets were excised, the aorta--right ventricular fistula was repaired with 4-0 Prolene pledgeted suture from within the left ventricular outflow tract. The aortic valve annulus was then sized and a 23-mm St. Jude Medical valve and conduit (St. Jude Medical, St. Paul, MN) inserted. Further inspection of the left main coronary artery revealed that the ostium was thin, friable, and unsuitable for reimplantation as a button to the conduit. Saphenous vein grafts were therefore anastomosed to the left anterior descending artery and the right coronary artery. The aorta at the level of the innominate artery was normal and the dissection was limited to the proximal portion of the ascending aorta. The distal aortic anastomosis was therefore performed with the cross-clamp on and with no period of circulatory arrest. After completion of the distal aortic anastomosis, the proximal anastomosis of the saphenous vein graft was performed directly onto the conduit. The patient was then weaned off of cardiopulmonary bypass without difficulty and required only minimal inotropic support. The patient's postoperative pulmonary capillary wedge pressure was 20 mm Hg, with a cardiac index of 2.2 L/m2.
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Fig 1. . Findings at operation showing the aortic dissection (A), aortopulmonary fistula (B), and aorta--right ventricular fistula (C).
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The patient's postoperative course was marked by severe right ventricular dysfunction and prolonged intubation, and she was ultimately discharged to a rehabilitation facility on postoperative day 35. The patient was seen for follow-up office visits on postoperative days 92 and 127, and her activities were noted to be minimally limited. A follow-up echocardiogram on postoperative day 92 showed a normally functioning aortic valve and severe biventricular dysfunction.
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Comment
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Aortic aneurysms secondary to syphilis, infection, arteriosclerosis, and trauma are well documented in the literature. These aneurysms can often rupture into the mediastinum, with death frequently ensuing. It is also known that these aneurysms can rupture into a cardiac chamber, pulmonary artery, or the superior vena cava. This is due to the proximity of the ascending aortic aneurysm wall to the cardiac chambers (right atrium, left atrium, and right ventricle) and the pulmonary artery. In 1924 Boyd [1] reviewed 4,000 autopsy reports of thoracic aortic aneurysms and found 1,197 instances of rupture with several cases of fistula formation to surrounding structures, including a 4% occurrence of aortopulmonary fistulization. No aorta--right ventricular fistulas were found.
Aortopulmonary fistulas are found more frequently in the setting of chronic disease of the aorta than in the setting of acute aortic dissections [2]. Fistulization to the pulmonary artery, right atrium, and right ventricle in the setting of acute dissections have all been reported in the literature. McCarthy and associates [3], in 1972, reported a case of acute dissection of the aorta in which the dissection extended through a patent ductus arteriosus, with ultimate fistulization to the pulmonary artery. Keenan [4] and Glanz [2] and their colleagues have also observed such fistulas between the aorta and pulmonary artery occurring as the result of acute aortic dissection. Perryman and Gay [5] reported the only case of an aortic dissection fistulizing to the right ventricle. Rupture of an acute aortic dissection into the right atrium with fistula formation, found at autopsy, was first reported by Kuipers and Schatz [6] in 1963.
Aortopulmonary, aorta--right atrial, and aorta--right ventricular fistulas all produce left-to-right shunt. Imaging plays an important role in the diagnosis of these fistulas. In the past, these fistulas were most frequently diagnosed by aortography and cardiac catheterization, if discovered before the patient's death. Many more, however, were diagnosed post mortem. Echocardiography is a commonly used imaging technique that has become an important tool in the diagnosis of aortic dissection. Two-dimensional echocardiography has the capacity to visualize aortic dissections very well [7]. If on physical examination one suspects the presence of a fistula, Doppler echocardiography can be used to further visualize the flow from one compartment to another. It also has the advantage of being able to evaluate left ventricular function and to determine whether there is aortic insufficiency [8]. Veerbeek and associates [9] used transthoracic Doppler echocardiography in the diagnosis of an aortopulmonary fistula. This was followed by aortography, which confirmed the diagnosis.
In summary, although aortopulmonary, aorta--atrial, and aorta--ventricular fistulas are uncommon in the setting of acute aortic dissections, these complications can be diagnosed preoperatively as long as they are kept in the differential diagnosis whenever patients present with the classic symptoms of left-to-right shunt. One must use all the information and imaging techniques at hand to ensure a timely diagnosis. Echocardiography has been shown to be an excellent technique for visualizing these complications. However, both magnetic resonance imaging and aortography failed to visualize the aortic dissection in our patient. This was probably due to the short segment of aorta involved in the dissection and run-off into the pulmonary circulation. Aortgraphy did reveal the fistulization with left-to-right shunting, but the findings led to the incorrect diagnosis of a ruptured aneurysm of the sinus of Valsalva.
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Footnotes
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Address reprint requests to Dr Spier, North Shore University Hospital, 300 Community Dr, Box 166, Manhasset, NY 11030.
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References
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- Boyd LJ. A study of four thousand reported cases of aneurysm of the thoracic aorta. Am J Med Sci 1924;168:654–63.
- Glanz S, Gordon DH, Shah N, Jaffe B, Griepp R. Unusual manifestations of aortic dissection. Cardiovasc Intervent Radiol 1982;5:292–5.[Medline]
- McCarthy C, Dickson GH, Besterman EMM, Bromley LL, Thompson AE. Aortic dissection, with rupture through ductus arteriosus into pulmonary artery. Br Heart J 1972;34: 428–30.[Free Full Text]
- Keenan DJM, Kieso HA, Johnson AM, Ross JK. Acquired aorto-pulmonary fistula: case report. Thorac Cardiovasc Surg 1984;32:190–2.[Medline]
- Perryman RA, Gay WA. Rupture of dissecting thoracic aortic aneurysm into the right ventricle. Am J Cardiol 1972;30: 277–81.[Medline]
- Kuipers FM, Schatz IJ. Prognosis in dissecting aneurysm of the aorta. Circulation 1963;27:658–61.[Abstract/Free Full Text]
- Granato JE, Dee P, Gibson RS. Utility of two-dimensional echocardiography in suspected aortic dissection. Am J Cardiol 1985;56:123–9.[Medline]
- Dagli SV, Nanda NC, Roitman D, et al. Evaluation of aortic dissection by color-flow mapping. Am J Cardiol 1985;56:497–8.[Medline]
- Veerbeek AG, Van Der Wieken LR, Schuilenburg RM, Bloemendaal K. Acquired aorto-pulmonary fistula in acute dissection. Eur Heart J 1992;13:713–5.[Abstract/Free Full Text]
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Abstract
Introduction
