The Management of Aneurysmal Degeneration of Lower Extremity Cryopreserved Saphenous Vein Bypass Grafts.

BACKGROUND: The use of cryopreserved saphenous veins (CSVs) for the treatment of lower extremity peripheral arterial disease is an attractive option when there is no available autogenous vein. Prior studies found CSVs are at risk for aneurysmal degeneration requiring reoperation. As the management of these complications and patient outcomes is not well described, the objective of this case series is to describe the open and endovascular management of degenerative CSVs at a tertiary community center. METHODS: All CSVs implanted for lower extremity bypass at our institution between 2001 and 2021 were retrospectively reviewed. All CSVs with evidence of aneurysmal change were included in this study. CSVs with evidence of active infection were excluded. The decision to intervene was left to the discretion of the operating surgeon. Demographic data, indications for the index operation, and details about subsequent interventions for degenerative CSVs were recorded. Study end points included limb salvage and continued patency. Demographic data, indications for the index operation, and details about subsequent interventions for degenerative CSVs were recorded. RESULTS: Seventeen bypasses were identified to have aneurysmal degeneration in 13 patients in the absence of infection between 2001 and 2021. Nine of the 13 patients were male, and the average age and body mass index during the index procedure were 72 and 28, respectively. Indications for the index bypass included acute limb ischemia (9), popliteal aneurysm (2), and chronic limb threatening ischemia with Rutherford's class IV (5) and V (1). The mean time between the index procedure and first graft revision due to aneurysmal changes was 4 years. Most of the aneurysms did not occur at the site of anastomosis with 13 occurring in the body of the graft. Thirteen grafts were managed with open surgery and 3 were managed with endovascular techniques. All endovascular repairs were managed via covered stenting. Patients were followed for an average duration of 7 years from the initial bypass and 2 years from their last aneurysmal repair. Limb salvage in this cohort was 87% with 2 limbs requiring amputation, all of whom underwent open reconstruction. The mortality rate in this series was 54% and no patients died due to complications from their graft. Continued patency on Kaplan Meier survival curve analysis was 79% at 6 months, 65% at 1 year, 54% at 3 years, and 27% at 5 years. CONCLUSIONS: In our experience, aneurysmal degeneration of CSV grafts was mostly managed with standard open surgical techniques, although endovascular therapy also proved acceptable. Limb salvage rates and continued patency of repair at 1 year in this cohort were acceptable. This case series highlights the importance of diligent surveillance for patients with CSVs.

Associations of intracranial artery length and branch number on non-contrast enhanced MRA with cognitive impairment in individuals with carotid atherosclerosis.

Developing novel risk markers for vascular contributions to cognitive impairment and dementia is important. This study aimed to extract total length, branch number and average tortuosity of intracranial distal arteries (A2, M2, P2 and more distal) from non-contrast enhanced magnetic resonance angiography (NCE-MRA) images, and explore their associations with global cognition. In 29 subjects (aged 40-90 years) with carotid atherosclerotic disease, the 3 intracranial vascular features on two NCE-MRA techniques (i.e. time of flight, TOF and simultaneous non-contrast angiography and intraplaque hemorrhage, SNAP) were extracted using a custom-developed software named iCafe. Arterial spin labeling (ASL) and phase contrast (PC) cerebral blood flow (CBF) were measured as references. Linear regression was performed to study their associations with global cognition, measured with the Montreal Cognitive Assessment (MoCA). Intracranial artery length and number of branches on NCE-MRA, ASL CBF and PC CBF were found to be positively associated with MoCA scores (P < 0.01). The associations remained significant for artery length and number of branches on NCE-MRA after adjusting for clinical covariates and white matter hyperintensity volume. Further adjustment of confounding factors of ASL CBF or PC CBF did not abolish the significant association for artery length and number of branches on TOF. Our findings suggest that intracranial vascular features, including artery length and number of branches, on NCE-MRA may be useful markers of cerebrovascular health and provide added information over conventional brain blood flow measurements in individuals with cognitive impairment.

Vessel length on SNAP MRA and TOF MRA is a potential imaging biomarker for brain blood flow.

PURPOSE: To explore feasibility of using the vessel length on time-of-flight (TOF) or simultaneous non-contrast angiography and intraplaque hemorrhage (SNAP) MRA as an imaging biomarker for brain blood flow, by using arterial spin labeling (ASL) perfusion imaging and 3D phase contrast (PC) quantitative flow imaging as references. METHODS: In a population of thirty subjects with carotid atherosclerotic disease, the visible intracranial arteries on TOF and SNAP were semi-automatically traced and the total length of the distal segments was calculated with a dedicated software named iCafe. ASL blood flow was calculated automatically using the recommended hemodynamic model. PC blood flow was obtained by generating cross-sectional arterial images and semi-automatically drawing the lumen contours. Pearson correlation coefficients were used to assess the associations between the different whole-brain or hemispheric blood flow measurements. RESULTS: Under the imaging protocol used in this study, TOF vessel length was larger than SNAP vessel length (P < 0.001). Both whole-brain TOF and SNAP vessel length showed a correlation with whole brain ASL and 3D PC blood flow measurements, and the correlation coefficients were higher for SNAP vessel length (TOF vs ASL: R = 0.554, P = 0.002; SNAP vs ASL: R = 0.711, P < 0.001; TOF vs 3D PC: R = 0.358, P = 0.052; SNAP vs 3D PC: R = 0.425, P = 0.019). Similar correlation results were observed for the hemispheric measurements. Hemispheric asymmetry index of SNAP vessel length also showed a significant correlation with hemispheric asymmetry index of ASL cerebral blood flow (R = 0.770, P < 0.001). CONCLUSION: The results suggest that length of the visible intracranial arteries on TOF or SNAP MRA can serve as a potential imaging marker for brain blood flow.