Interventional Cardiology Detection of Complications After Aortic Stent Grafting Georgia Tsoumakidou and Elias Brountzos Second Department of Radiology, Attikon University Hospital, Athens University Medical School
Abstract
Today, endovascular aortic aneurysm repair (EVAR) is used as an alternative to open surgery. Although the peri-procedural mortality rate is lower with EVAR, there is a high rate of re-intervention that makes long-term surveillance necessary; therefore, we reviewed the possible complications that can occur after EVAR and focused on the different imaging strategies used for follow-up. So far, multidetector computed tomography angiography (MDCTA) is the most widely accepted surveillance method, but carries the risk of radiation and contrast nephrotoxicity. Radiography, MRA, duplex and contrast-enhanced ultrasonography can also provide high-quality imaging, each with its own advantages and limitations. The ideal follow-up protocol (time intervals and type of imaging modality) needs to be further defined in order to ensure proper endograft function and prevent complications.
Keywords
Endovascular aortic aneurysm repair, endoleak, stent-graft, surveillance, magnetic resonance angiography, computed tomography angiography, contrast-enhanced ultrasonography, rupture
Disclosure: The authors have no conflicts of interest to declare. Received: 19 April 2010 Accepted: 18 May 2010 Citation: European Cardiology, 2010;6(2):83–7 Correspondence: Georgia Tsoumakidou, Second Department of Radiology, Athens University Medical School, Attikon University Hospital, 1 Rimini St, 12462 Chaidari, Greece. E:
gtsoumakidou@yahoo.com
During the last few decades, the endovascular repair of aortic aneurysms (EVAR) has revolutionised the treatment of thoracic and abdominal aortic aneurysms. Since 1991, when Parodi et al.1 reported the first series of successful endovascular abdominal aneurysm repair in humans, enormous developments have been accomplished in techniques, materials and equipment. More delicate techniques and sophisticated materials have made possible the treatment of most difficult cases (with short proximal neck anatomy, aneurysm sac involving the origins of major arterial branches and kinking of the aorta).
Randomised comparisons with open surgery have shown that EVAR has lower peri-procedural mortality (relative risk reduction of 3.1), fewer peri-procedural complications and sustained reduced aneurysm- related mortality at four years (4% for EVAR, 7% for open repair).2,3 However, EVAR has its limitations, foremost among which is the need for re-intervention, as complication rates can be as high as 41%.2
Late
complications requiring re-intervention are much less frequent, at rates of approximately 2.1–2.8%.4
The most serious complications include endoleaks, infection, graft migration and rupture.
Due to these potential problems inherent to EVAR, lifelong surveillance is currently recommended using different imaging methods. Imaging should focus on the following parameters: measurement of the aortic sac diameter, detection and classification of endoleaks and detection of any failure of the structural integrity of the endograft.5
The
ideal follow-up modality should be inexpensive, widely available, reproducible and accurate, without radiation exposure.
© TOUCH BRIEFINGS 2010
Complications After Aortic Stent Grafting Rupture
Rupture is the most feared complication that can be encountered after EVAR;6
although it does not occur frequently (1% per year),7 due
to its high mortality rate it should always be kept in mind. Predisposing factors for rupture include endoleaks (usually type I and III), stent-graft migration, disintegration and infection. Rupture of the aneurysm can occur long after the procedure, and has been encountered even in cases with proven sac shrinkage. It is believed that an adverse event such as type III or I endoleak, stent-graft disintegration or device migration results in a sudden increase of endosac pressure, thus leading to rupture.
Since the published results of the EUROpean collaborators on Stent– graft Techniques for abdominal aortic Aneurysm Repair (EUROSTAR) study,7
which reported an annual cumulative rate of rupture of around 1% per year, with recent stent-grafts and techniques/follow-up protocols the rate has declined to around 0.5% per year.8
The rupture-
associated mortality rate is high (60%), regardless of the treatment option (endovascular or open surgical repair).8
Endoleaks
An endoleak is defined as a blood flow external to the stent-graft and inside the aneurysm sac. Endoleaks can sometimes be difficult to diagnose and treat. Five types of endoleak have been described.9 Type I endoleak is caused by the absence of a seal between the endograft and the wall of the artery; blood flow originates from a stent-graft attachment site (proximal or distal). Immediate type I
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