Ann Thorac Surg 2009;87:1279-1281. doi:10.1016/j.athoracsur.2008.08.066
© 2009 The Society of Thoracic Surgeons
Case Reports
Acute Type A Aortic Dissection Complicated by Aortic Stent Graft Collapse
Zoltan Szabolcs, MD, PhD*,
Kalman Hüttl, MD, PhD,
Agnes Laczko, MD,
Laszlo Daroczi, MD,
Tivadar Hüttl, MD, PhD,
Erzsebet Paulovich, MD,
Istvan Hartyanszky, MD
Department of Cardiovascular Surgery, Semmelweis University, Budapest, Hungary
Accepted for publication August 26, 2008.
* Address correspondence to Dr Szabolcs, Department of Cardiovascular Surgery, 68 Varosmajor Str, H-1122 Budapest, Hungary (Email: szabzol51{at}t-online.hu).
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Abstract
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A 57-year-old man complaining of chest pain presented with signs of lower limb ischemia 1 year after implantation of a stent graft at the aortoiliac bifurcation. A computed tomography scan revealed the presence of a type A aortic dissection and complete collapse of the stent graft by bulging of the false lumen. The patient underwent emergency surgical reconstruction of the aortic root and arch, which allowed reexpansion of the previously collapsed stent graft. Stenting of residual stenoses distal to the stent graft and of an occluded left renal artery was also successful.
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Introduction
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Because of their high safety and efficacy, endovascular procedures have become a widely accepted alternative to surgical interventions for the treatment of aortobiiliac aneurysms [1, 2]. On the other hand, with the rapidly growing rate of stent grafts implantation, previously unknown although potentially life-threatening procedure-related complications and long-term adverse events may occur [3, 4]. We observed the complete collapse of an aortobiiliac stent graft by the false lumen of a type A aortic dissection.
A 57-year-old man with a history of hypertension underwent uncomplicated implantation of an aortic bifurcation Excluder endoprosthesis (W. L. Gore & Assoc Inc, Flagstaff, AZ) in November 2004 after an ultrasound examination had revealed a 4.5-cm infrarenal aortic aneurysm. Precisely 1 year after the stent graft implantation, the patient suddenly experienced a tearing pain across the anterior and posterior thorax, soon followed by numbness and paresis of the lower limbs.
Upon readmission to our department, the patient presented with pale and cold lower extremities and weaker femoral pulses than on prior examinations. A loud diastolic murmur was heard on auscultation, attributed to the acute onset of aortic valve dysfunction. A transthoracic echocardiogram confirmed the diagnosis of aortic valve insufficiency and revealed an intimal flap inside a dilated aortic root. A computed tomography scan confirmed our suspicion of acute type A aortic dissection (Fig 1), with a dilated false lumen occluding nearly completely the bifurcated stent graft (Fig 2), explaining the ischemic changes observed in the lower extremities.
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Fig 1. A preoperative computed tomography scan shows the prominent compression of the true (T) by the false (F) lumen of the ascending aorta.
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Fig 2. A preoperative computed tomography scan shows that the lumens of the bifurcations stent graft (arrows) are totally occluded by the false lumen.
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The patient underwent an urgent open operation performed by a cardiac surgical team (ZS, LD, TH and IH), followed by a percutaneous endovascular procedure performed by an interventional radiologist and a vascular surgeon (KH and AL) to restore blood flow at the aortoiliac level.
Under extracorporeal circulation by means of axilloatrial cannulation, the chest and pericardium were opened, and 300 mL of fresh blood was drained. The adventitia of the ascending aorta was discolored and oozing. After the ascending aorta was cross-clamped, a longitudinal aortotomy was performed, and the heart was arrested by administration of a cardioplegic solution of crystalloid. A first intimal tear was found at the level of the coronary ostia and a second in the aortic arch. The cerebral circulation was isolated for 40 minutes during opening and replacement of the aortic arch. The aortic root was reconstructed by a Bentall procedure using a 27-mm SJM mechanical valved conduit (St. Jude Medical Inc, St. Paul, MN). After the patient withdrawn from cardiopulmonary bypass, anticoagulation was fully reversed by the administration of protamine (3 mg/kg) to reach an activated clotting time of 100 seconds or less.
Despite a stable hemodynamic status, the patient's femoral pulses remained impalpable after closure of the chest wall, and the ischemic manifestations of the lower extremities continued to evolve. After incision of the left common femoral artery and confirmation of a markedly decreased blood flow, we were unable to advance a Fogarty catheter beyond a length of 10 cm, probably because of an occluded distal end of the stent graft.
Heparin (10,000 U) was administered to obtain an activated partial thromboplastin time of between 80 and 100 seconds. The patient was transferred to the catheterization laboratory under general anesthesia, where an aortography showed the vascular anatomy expected after the Bentall procedure and aortic arch replacement, as well as a marked decrease in blood flow through the false lumen. The previously compressed stent graft was reexpanded, but the blood flow through its lumen remained slow and was completely absent through the left renal artery. Residual iliac artery stenoses were present distal to the ends of both bifurcated stent segments. Balloon angioplasties of the left renal artery and left and right iliac arteries stenoses were performed, followed by stent implantations. The patient was then returned to the operating room for persistent bleeding through the chest tubes, although no distinct hemorrhagic source was identified.
After 11 hours of complex surgical and percutaneous interventions, the patient was admitted to our intensive care unit with palpable femoral pulses and a severe revascularization syndrome of the right lower extremity that required extensive open fasciotomy on day 1 postoperatively. Despite a postoperative period further complicated by transient oligoanuria, the patient was discharged from the hospital on day 13 in stable condition and with peripheral pulses palpable bilaterally.
At 2.5 years of follow-up, the patient has remained free of symptoms. An echocardiogram obtained 24 months after the hybrid procedure showed no regional wall motion abnormality, a left ventricular ejection fraction of 0.57, and normal prosthetic aortic valve function. A computed tomography scan showed the stent graft was patent (Fig 3).
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Fig 3. A postoperative computed tomography scan 2.5 years after the hybrid procedure shows that the lumens of the bifurcation stent graft (arrows) are fully reexpanded.
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Comment
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The unique presentation of our case was the development of a type A aortic dissection in a patient with a previously implanted aortobiiliac stent graft. The key observations that we made were related to the effects of the stent graft collapse on the pathologic changes and clinical manifestations of the dissection, and vice versa.
First, we found that the endovascular graft behaved like a true vascular lumen with respect to the dissection process. Although the stent graft was completely collapsed by the pressure inside the false lumen, it reexpanded after repair of the proximal aorta. Second, the stent graft caused a markedly decreased perfusion of the lower extremities and the pelvic vessels by preventing the return of blood flow at the distal end of the dissected membrane near the aortic bifurcation. Because the stent graft was collapsed, the dissection extended into both common iliac arteries and ended in blind pockets immediately distal to the stent graft. The latter ultimately became occluded by a thrombus, which most likely developed during the 6 hours that elapsed between the onset of dissection and the surgical repair.
Repair of the proximal aorta allowed reexpansion of the stent, but short segments of both common iliac arteries remained occluded by the mechanical compression of the thrombosed blind pockets at the distal end of the false lumen. We therefore proceeded with balloon angioplasty, followed by stent implantation to restore blood flow through these occluded vessels. Because the proximal segment of the left renal artery was included in the wall of the false lumen, perfusion through the false lumen after aortic repair supplied insufficient blood flow to the left kidney. The bifurcated endovascular graft was more distal and thus was not implicated in the poor perfusion of the left renal artery, which was restored by implantation of a stent originating from the true lumen.
With respect to our overall management strategy, this patient represented a surgical emergency because the presence of pericardial tamponade was life threatening. Therefore, was gave the aortic repair an absolute priority. We wish to emphasize that the availability of hybrid surgical and endovascular procedural facilities, and the close cooperation among cardiac and vascular surgeons, the interventional radiologist and the anesthesiologist, were key to the successful management of this complex clinical presentation.
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References
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- Parodi JC. Endovascular repair of abdominal aortic aneurysms and other arterial lesions J Vasc Surg 1995;21:549.[Medline]
- Palma JH, de Souza JA, Rodrigues Alves CM, Carvalho AC, Buffolo E. Self-expandable aortic stent-grafts for treatment of descending aortic dissections Ann Thorac Surg 2002;73:1138-1142.[Abstract/Free Full Text]
- Lalka S, Dalsing M, Cikrit D, et al. Secondary interventions after endovascular abdominal aortic aneurysm repair Am J Surg 2005;190:787-794.[Medline]
- Harris P, Brennan J, Martin J, et al. Longitudinal aneurysm shrinkage following endovascular aortic aneurysm repair: a source of intermediate and late complications J Endovasc Surg 1999;6:11-16.[Medline]
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Abstract
Introduction
