Ann Thorac Surg 2003;75:1961-1963
© 2003 The Society of Thoracic Surgeons
Case report
A rare case of aortic tube graft occlusion 35 years after coarctectomy
Naoto Ashizawa, MDa*,
Hirofumi Tasaki, MDa,
Riyako Shibata, MDa,
Yuji Koide, MDa,
Shinji Seto, MDa,
Shiro Yamachika, MDb,
Shiro Hazama, MDb,
Kiyoyuki Eishi, MDb,
Katsusuke Yano, MDa
a Departments of Cardiovascular MedicineNagasaki University, Nagasaki, Japan
b Cardiovascular Surgery, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
Accepted for publication November 26, 2002.
* Address reprint requests to Dr Ashizawa, Department of Cardiovascular Medicine, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki City, Nagasaki 852-8501, Japan
e-mail: mikan{at}net2.nagasaki-u.ac.jp
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Abstract
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A 52-year-old male with a history of repair of aortic coarctation by prosthetic tube graft replacement 35-years ago developed anterior spinal artery syndrome caused by acute functional occlusion of the aorta at the repair site where pseudoaneurysm formation was observed. The patient was rescued by an emergency axillofemoral bypass, and residual hypertension in upper limbs was improved by elective ascending aorta-descending aorta bypass grafting.
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Introduction
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Aortic coarctation is nowadays rarely observed among adult population, as it is usually treated during infancy. Recurrent hypertension is common despite successful repair of aortic coarctation, and is one of the major risk factors in late postoperative mortality and morbidity, including cerebrovascular complications, recoarctation, aneurysm formation, aortic rupture, and coronary artery disease [1, 2].
This is the first case of acute aortic occlusion as a late complication of coarctation repair with Teflon tube graft replacement (DuPont Pharmaceuticals, Wilmington, DE). This case illustrates the possible mechanisms of anterior spinal artery syndrome (ASAS).
On November 23, 2001, a 52-year-old male was urgently admitted, suffering from sudden onset of lower extremity pain, and weakness.
He had noticed uncontrolled upper limb systemic hypertension and diagnosed aortic coarctation at 17 years of age. Aortography revealed tapered narrowing of the proximal descending aorta 3 cm in length, and the pressure gradient was 120 mm Hg. After coarctectomy, Teflon tube graft replacement (1.4 x 5.5 cm) was performed and blood pressure (BP) in his upper limb decreased to the range of 130 to 140/70 to 75 mm Hg without medications. In June 1986 (37 years old), he was readmitted to our hospital for evaluation of hypertension (170 to 190/80 to 100 mm Hg). A digital subtraction aortogram revealed that the graft, with a diameter approximately half the native aorta, was patent. His BP was well controlled by captopril 37.5 mg/d.
In August 2000 (51 years old), the patient complained of hoarseness due to left recurrent nerve palsy. Computed tomography (CT) revealed a 3-cm diameter pseudoaneurysm in the proximal portion of the graft. We recommended reoperation, however he refused at that time. Ambulatory BP monitoring (ABPM) revealed well-controlled values using multiple antihypertensive agents: awake mean SBP 133 mm Hg; asleep mean SBP 123 mm Hg. Moreover the pressure gradient across the graft was 24 mm Hg; therefore we decided to follow him in outpatient clinic with close observation.
On emergency admission, the patient initially presented severe hypertension in the upper limbs (240/90 mm Hg) with absent pulses in both lower extremities by palpation and Doppler. A harsh widespread systolic murmur, which had been audible throughout the chest wall and interscapular back, had almost disappeared and bowel sounds were decreased. On neurologic examination, he revealed severe weakness of lower extremities without deep tendon reflex. Incomplete sensory dissociation below the level of Th11 was observed. Because these findings strongly suggested ASAS, the patient underwent emergency CT, which illustrated a pseudoaneurysm with a 3.5-cm diameter just proximal to the coarctation repair site. There was delayed and minimal filling of the distal descending thoracic aorta probably through collateral vessels (Fig 1).
In an attempt to rescue his lower extremities from anoxia, we performed an inverted Y-graft (with an 8-mm ringed Gore Tex [W.L. Gore and Associates, Flagstaff, AZ]) from the right axillary artery to both common femoral arteries about 4 hours after the occlusion.
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Fig 1. Computed tomographic scan illustrating a pseudoaneurysm formation just proximal to the coarctation repair site.
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Although the blood supply in the lower extremities became a little better, muscle weakness and dissociated sensory impairment continued and anuresis became obvious. BP in upper extremities was high (ABPM: awake mean, 178/75 mm Hg; asleep mean, 175/79 mm Hg) and plasma renin concentration (PRC) was high (72.8 pg/mL, normal range 2.5 to 21.4). In contrast, SBP in lower extremities was about 80 mm Hg and ankle brachial pressure index (ABPI) was around 0.4.
On February 8, 2002, about 2.5 months after urgent operation, we performed ascending aorta to descending aorta bypass graft with 18-mm Gelweave (Vascutek, Renfrewshire, United Kingdom) and patch closed the distal arch just distal to the left subclavian artery using the rest of the Teflon graft. We confirmed the Teflon graft had been detached from the proximal margin of the anastomotic suture line to form the pseudoaneurysm. After the operation, weakness and coldness of lower extremities improved remarkably and a second ABPM performed on March 5, 2002 revealed improvement (awake mean 104/70 mm Hg, asleep mean 105/69 mm Hg) in accordance with the normalization of PRC (17.0 pg/mL). A magnetic resonance angiography illustrated both right axillofemoral bypass and ascending aorta–descending aorta bypass grafts were patent (Fig 2).
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Fig 2. Magnetic resonance angiography performed on March 6, 2002, revealed both right axillofemoral bypass graft (November 23, 2001) and ascending aorta–descending thoracic aorta bypass graft (February 8, 2002) were patent.
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On March 25, the patient was discharged from the hospital walking with a stick.
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Comment
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Late postoperative morbidity and mortality following coarctation repair in adulthood are predominantly related to the presence of hypertrension, especially its severity and duration. Prosthetic tube graft replacement was performed as the preferred method for repairing aortic coarctation not suitable for direct end-to-end anastomosis and the incidence of reintervention or aortic aneurysm formation was lower than patch angioplasty or end-to-end anastomosis [1–3]. Pseudoaneurysms arise from suture lines or at isthmic restenosis, whereas true aneurysms usually formed opposite to a patch graft repair [1–3]. Prevalence of aneurysm formation after coarctation repair by tube graft is 12/184 (6%) [3], however only three reports have been published about pseudoaneurysm [3–5]. Most studies have used clinical criteria to define recurrence of coarctation as a measured arm-leg SBP gradient of more than 15 to 20 mm Hg. Recurrent recoarctation is mainly associated with repair during infancy and it appears to be common in patients undergoing repair by subclavian flap aortoplasty or unsuitable for end-to-end anastomosis [1]. Taking these into consideration, the main cause of the formation of psudoaneurysm at the site of previous repair in our patient is postoperative systemic hypertension due to use of an inadequately small Teflon tube graft considering his constitution, and long-standing hypertension causes stress and turbulence at the coarctation repair site.
Williams and coworkers [4] reported a 42-year-old male with a history of repair of coarctation of the aorta with Dacron tube graft (DuPont Pharmaceuticals, Wilmington, DE) 16 years before, developed sudden onset of aortic occlusion. Similar to our patient, they tried to provide blood flow to the lower extremities by an inverted Y-graft from the ascending aorta to the femoral arteries. However, during surgery, the patient developed severe coagulopathy and died shortly thereafter. Autopsy demonstrated dehiscence of the proximal suture line of the tube graft, which resulted in a flap-valve effect, pseudoaneurysm formation, and acute functional occlusion of the aorta. Importantly there was evidence of neither dissection nor true aneurysm. We also detected the existence of dehiscence of the proximal suture line of the Teflon tube graft and the graft was detached from the aorta and formed the pseudoaneurysm. Therefore flap-valve effect was a plausible theory to explain the mechanism of acute onset of ASAS, a rare complication after surgery of the thoracic or abdominal aorta. The mechanisms of spinal cord injury are various; however, it is generally agreed that microembolization is responsible for its occurence. In particular, the lower spinal cord is susceptible to systemic hypotension because of the lack of collateral blood supply. The origin of microemboli in our patient is most likely the pseudoaneurysm, which is filled with thrombus.
Despite a partially successful reconstruction of blood supply to the lower limbs by means of inverted Y-graft, hypertension in upper limbs was continued. A graft size was not large enough to obtain blood supply for lower extremities and marked decrease of renal blood flow led to overt secretion of renin. We then selected an ascending aorta–descending aorta bypass as a sure and safe procedure to accomplish the original aim and, fortunately, hemodynamic improvement was satisfactorily achieved. Substantially, axillofemoral bypass and ascending aorta–descending aorta bypass are antianatomic reconstructions of blood supply, however, from a lifesaving point of view there is no other substitutional ways.
Finally, we emphasize that the possibility of occurence of ASAS should be kept in mind when pseudoaneurysm is growing at the proximal site of coarctation repair, particularly when systemic hypertension is existing.
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References
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- Jenkins N.P., Ward C. Coarctation of the aorta: natural history and outcome after surgical treatment. Q J Med 1999;92:365-371.[Free Full Text]
- Toro-Salazar O.H., Steinberger J., Thomas W., Rocchini A.P., Carpenter B., Moller J.H. Long-term follow up of patients after coarctation of the aorta repair. Am J Cardiol 2002;89:541-547.[Medline]
- Kodolitsch Y., Aydin M.A., Koschyk D.H., et al. Predictors of aneurysmal formation after surgical correction of aortic coarctation. J Am Coll Cardiol 2002;39:617-624.[Abstract/Free Full Text]
- Williams C.R., Nilakhe V., Clouse M.E. Acute aortic occlusion as a late complication of coarctation repair. Cardiovasc Intervent Radiol 1989;12:286-289.[Medline]
- Stern A., Mindich B.P., Halperin J.L. Extraluminal compression of an aortic graft simulating recoarctation. Br Heart J 1987;57:286-288.[Abstract/Free Full Text]
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Abstract
Introduction
