Case Presentation - April 2013
W. Michael Park, MD
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Emergent treatment of descending thoracic aortic dissection causing kidney failure and severe hypertension treated with a complex endovascular approach.
The patient is a 51 year old man with prior history of difficult to control blood pressure and smoking who presented to an outside institution about a week prior to presentation with severe chest pain associated with shortness of breath. At presentation there, his blood pressure was 248/119. CT scan (figure 1) revealed a descending thoracic aortic dissection. He had acute renal failure with an elevated creatinine that peaked at 2.4mg/dL. His blood pressure was eventually controlled on a 5 drug regimen which included clonidine, Cozaar, Coreg, hydralazine, and amlodipine. Despite this, his blood pressure remained persistently above 160mmHg systolic, and he had persistent back pain. His renal function stabilized at a creatinine of 1.8, indicating that he had lost almost 50% of his baseline kidney function. He was going to be discharged for medical management of his dissection. He requested a second opinion here at Cleveland Clinic and he was transferred by air.
On arrival, his blood pressure remained above 160mmHg and he remained symptomatic of back pain. I reviewed his CT scan and saw that he had compressed most of his true lumen, and this compromised flow into the kidneys which were perfused by the false lumen. He also had diminished flow lumen into his abdominal viscera (stomach, liver, intestines) and legs, although he remained asymptomatic in these vascular beds. His continued back pain concerned me because this could herald eventual rupture if his blood pressure remained high. Long term, this was a consideration as well and the fact that he was young meant that he was most likely to suffer the side effects on taking many blood pressure medications – including lethargy, depression, and impotence.
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Plan was made for operation. The goal was to reestablish true lumen flow by closing off the proximal entry point and supporting the true lumen to allow it to fully reexpand. This was to be done with a thoracic stent graft sized appropriately for the total size of the aortic adventitia. The hybrid stent graft/stent devices for dissection are not commercially available in the US, and therefore an available stent graft was chosen to cover the proximal dissection. Any residual stenosis in the renal arteries and others would then be treated with stenting from the true lumen. This would allow for reperfusion of the kidneys and hopefully better control of his blood pressure and improved kidney function. Incidentally, his femoral and iliac arteries were of a size suitable for a total percutaneous repair.
Because the dissection started next to the left subclavian artery, the thoracic stent graft to be placed to seal the proximal start point of the dissection would cover the left subclavian artery orifice. Therefore a bypass from the left common carotid artery to the left subclavian artery was planned to avoid loss of flow to the left hand and to the left vertebral artery (see figure 2).
The operation was performed in two stages. First, the left common carotid artery to left subclavian artery bypass was performed. This would allow me to cover the origin of the left subclavian artery with the stent graft and preserve flow to the left arm and more importantly to the left vertebral artery to the brain. After this was done, the patient was re-prepped and both common femoral arteries were accessed under ultrasound.
The ultrasound showed on B-mode only single lumena to the common femoral arteries, suggesting that the dissection had not extended to the groins and that true lumen access would be possible. Wire access was achieved up to the aortic arch and intravascular ultrasound (IVUS) was used to confirm that the wires were in the true lumen (figure 3). A thoracic stent graft (Gore TAG) was deployed across the origin of the left subclavian artery to seal off the origin of the false lumen flap (figure 4) and extended to the thoracic aorta above the celiac axis. IVUS confirmed reestablishment of true lumen flow into the visceral segment of aorta. Selective renal arteriography showed stenoses due to the false lumen flaps which were treated with stents (left side shown, figure 5) . The flap impinged on iliac flow by IVUS and arteriography, and this area was stented (figure 6) . The arterial access sites were repaired with preplaced Perclose sutures.
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The patient recovered well with excellent blood pressure response with systolic pressures at discharge in the 120mmHg range on four medications that were reduced to three after discharge. Gratifyingly, his pain remitted and his renal function improved (Figure 7).
While there are theoretical benefits to endovascular treatment of type B thoracic aortic dissection, a randomized trial failed to prove a difference in two year survival between medically managed and stented grafted groups, but the aortas in the stented group had better remodeling (Reference 1). When thoracic endografting and endovascular therapy is used to treat malperfusion, there is 2.8-16% early mortality rate, a 1.5-9.5% stroke rate, and a 0-2.8% paraplegia rate. There is a risk of retrograde dissection, and conversion to a type A dissection, of 1.9%, and a reintervention rate of 7.6%. The long term results are unknown. That said, in carefully selected individuals with good anatomy, and with the right equipment, successful outcomes are possible.
- Nienaber CA et al. Circulation. 2009 Dec 22;120(25):2519-28