Advantages of Intravascular Ultrasound (IVUS) Guided Endografting for Aortic Pathologies From A 6-Year Experience
Martin R Back, Hollie Gaeto, Paul Armstrong
USF Vascular, Tampa, FL
INTRODUCTION: An audit of all primary and secondary
thoracic and abdominal endograft procedures performed
for aortic pathologies (aneurysm, dissection, traumatic) sought to define the
relative safety, technical accuracy, specific indications and advantages of
IVUS guidance relative to standard use of contrast arteriography.
METHODS: 437 consecutive aortic procedures done by a single operator from 10/2005 to 7/2011 (period of IVUS availability) were reviewed with IVUS needed in 43% of cases (n=188). IVUS was used in 73 of 109 (67%) thoracic (40/65 aneurysms,all 25 type B dissections,1/5 traumatic injuries) or hybrid thoracoabdominal (8/14) procedures with >2 vessel visceral debranching and in 115 of 328 (35%) aortoiliac aneurysm cases. Prior to device deployment, IVUS localized device landing sites at aortic branches, assessed wall morphology, assisted device sizing by diameter measures and optimized device positioning in all cases, and defined true/false lumen anatomy, entry sites and fenestrations within dissections. IVUS confirmed gate cannulations for bifurcated devices, adequacy of luminal/device expansion within treated segments, branch artery patency, and potential access vessel injury. For patients with renal compromise (Cr>1.5mg/dL, single or transplanted kidney) intent was to deploy endografts with IVUS-assistance and perform only completion contrast imaging to assess for residual endoleak, branch patency and device expansion. Endograft coverage from renals to hypogastrics was planned for all AAA patients to optimize fixation.
RESULTS: Pre-op renal compromise was present in 23% of thoracic and 17% of abdominal cases. In those patients, IVUS was used in 89% of thoracic and 58% of abdominal cases. IVUS use was associated with significant reduction in contrast use for all abdominal cases (44+21cc v 106+43cc no IVUS, P=.01) but not for thoracic cases (mean 102cc v 113cc no IVUS, P>.05). While the overall incidence of worsening renal function (>50% increase Cr or dialysis) within 30 days was not different between IVUS (20/188,11%) and no IVUS (24/249,10%) cases, IVUS use significantly lessened renal insult compared with contrast-guidance only in patients with pre-op renal compromise (10% v 33% no IVUS,P=.03). There were no incidents of unintended aortic branch coverage in the series. A comparison of mean distances between proximal device and lowest renal (2.8 v 2.2mm) and distal limb to patent hypogastric (9 v 9.1mm) from post-op AAA CT scans showed no difference in accuracy of endograft placements by IVUS and contrast guidance for abdominal cases, respectively.
CONCLUSIONS: IVUS-guidance during aortic endografting facilitates accurate device deployment, can reduce contrast agent use and affords protection against worsening renal function in patients with underlying compromise.
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