The correlation between computed tomography and duplex evaluation of autogenous vein bypass grafts and their relationship to failure

• Published in: Journal of vascular surgery 2015-12, Vol.62 (6), p.1546-1554.e1
• Main Authors: Rehfuss, Jonathan, MD, Scali, Salvatore, MD, He, Yong, PhD, Schmit, Bradley, MD, Desart, Kenneth, MD, Nelson, Peter, MD, MS, Berceli, Scott, MD, PhD
• Format: Article
• Language: English
• Subjects: Aged; Angiography; Autografts; Confounding Factors (Epidemiology); Female; Graft Occlusion, Vascular - diagnostic imaging; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Middle Aged; Surgery; Tomography, X-Ray Computed; Ultrasonography, Doppler, Duplex; Vascular Patency; Veins - transplantation
• ISSN: 0741-5214; 1097-6809
• DOI: 10.1016/j.jvs.2015.06.220

Objective Duplex ultrasound (DUS) imaging for vein bypass graft (VBG) surveillance is confounded by technical and physiologic factors that reduce the sensitivity for detecting impending graft failure. In contrast, three-dimensional computed tomography angiography (CTA) offers high-fidelity anatomic characterization of VBGs, but its utility in detecting at risk grafts is unknown. The current study analyzed the correlation between DUS and CTA for detection of vein graft stenosis and evaluated the relationship of the observed abnormalities to VBG failure. Methods Consecutive lower extremity VBG patients underwent surveillance with concurrent DUS imaging and CTA at 1 week and at 1, 6, and 12 months postoperatively. A standardized algorithm was used for CT reconstruction and extraction of the lumen geometries at 1-mm intervals. At each interval, CT-derived cross-sectional areas were coregistered and correlated to DUS peak systolic velocities (PSVs) within six predesignated anatomic zones and then analyzed for outcome association. Vein graft failure was defined as pathologic change within a given anatomic zone resulting in thrombosis, amputation, or reintervention within the 6-month period after the observed time point. Results The study recruited 54 patients, and 10 (18%) experienced failure ≤18 months of implantation. The expected inverse relationship between cross-sectional area and PSV was only weakly correlated (Spearman rank coefficient = −0.19). Moderate elevations in the PSV ratio (PSVr ; 2-3.5) were frequently transient, with 14 of 18 grafts (78%) demonstrating ratio reduction on subsequent imaging. A PSVr ≥3.5 was associated with a 67% failure rate. CT stenosis 80%) CT stenosis was more likely to succeed than to fail (25%). Significant discordance between CT and DUS was found in 18 patients. Although 14 of these patients had CT stenosis >70% with a PSVr