Predicting future occlusion or stenosis of lower extremity bypass grafts using artificial intelligence to simultaneously analyze all flow velocities collected in current and previous ultrasound examinations.

Objective: Routine surveillance with duplex ultrasound (DUS) examination is recommended after femoral-popliteal and femoral-tibial-pedal vein bypass grafts with various intervals postoperatively. The presently used methodology to analyze bypass graft DUS examination does not use all the available data and has been shown to have a significant rate for missing impending bypass graft failure. The objective of this research is to investigate recurrent neural networks (RNNs) to predict future bypass graft occlusion or stenosis. Methods: This study includes DUS examinations of 663 patients who had bypass graft operations done between January 2009 and June 2022. Only examinations without missing values were included. We developed two RNNs (a bidirectional long short-term memory unit and a bidirectional gated recurrent unit) to predict bypass graft occlusion and stenosis based on peak systolic velocities collected in the 2 to 5 previous DUS examinations. We excluded the examinations with missing values and split our data into training and test sets. Then, we applied 10-fold cross-validation on training to optimize the hyperparameters and compared models using the test data. Results: The bidirectional long short-term memory unit model can gain an overall sensitivity of 0.939, specificity of 0.963, and area under the curve of 0.950 on the prediction of bypass graft occlusion, and an overall sensitivity of 0.915, specificity of 0.909, and area under the curve of 0.912 predicting the development of a future critical stenosis. The results on different bypass types show that the system performs differently on different types. The results on subcohorts based on gender, smoking status, and comorbidities show that the performance on current smokers is lower than the never smoker. Conclusions: We found that RNNs can gain good sensitivity, specificity, and accuracy for the detection of impending bypass graft occlusion or the future development of a critical bypass graft stenosis using all the available peak systolic velocity data in the present and previous bypass graft DUS examinations. Integrating clinical data, including demographics, social determinants, medication, and other risk factors, together with the DUS examination may result in further improvements. Clinical Relevance: Detecting bypass graft failure before it occurs is important clinically to prevent amputations, salvage limbs, and save lives. Current methods evaluating screening duplex ultrasound examinations have a significant failure rate for detecting a bypass graft at risk for failure. Artificial intelligence using recurrent neural networks has the potential to improve the detection of at-risk bypass graft before they fail. Additionally, artificial intelligence is in the news and is being applied to many fields. Vascular surgeons need to know its potential to improve vascular outcomes.

Endovascular Repair of an Intrathoracic Subclavian Artery Aneurysm in a Patient With Dextrocardia.

This manuscript describes an endovascular repair of a symptomatic, large proximal left subclavian artery aneurysm in a patient with dextrocardia and right-sided aortic arch and absent bilateral internal carotid arteries. The patient had surgical reconstruction as an infant for congenital heart disease with Ventricular Septal Defect, bifid sternum . Given her previous surgical history, we declined an open operation and performed an endovascular repair with stent grafts to successfully repair the subclavian artery aneurysm. The patient had an uneventful postoperative course and follow-up ultrasonography demonstrated successful repair with preservation of flow through the left subclavian and vertebral arteries with resolution of her symptoms.

An Interesting Case of a Patient With Disabling Bilateral Lower Extremity Claudication and a Persistent Sciatic Artery.

A persistent sciatic artery is a rare congenital anomaly. This case report highlights the treatment for a patient with a persistent sciatic artery no longer in continuity with the internal iliac artery and atherosclerotic peripheral vascular disease resulting in disabling bilateral lower extremity claudication. It highlights the types and anatomic locations of the sciatic artery and discusses an effective way to treat a patient with arterial insufficiency and this variant anatomy as well as other treatment options.

A new noninvasive and patient-specific hemodynamic index for the severity of renal stenosis and outcome of interventional treatment.

Renal arterial stenosis (RAS) often causes renovascular hypertension, which may result in kidney failure and life-threatening consequences. Direct assessment of the hemodynamic severity of RAS has yet to be addressed. In this work, we present a computational concept to derive a new, noninvasive, and patient-specific index to assess the hemodynamic severity of RAS and predict the potential benefit to the patient from a stenting therapy. The hemodynamic index is derived from a functional relation between the translesional pressure indicator (TPI) and lumen volume reduction (S) through a parametric deterioration of the RAS. Our in-house computational platform, InVascular, for image-based computational hemodynamics is used to compute the TPI at given S. InVascular integrates unified computational modeling for both image processing and computational hemodynamics with graphic processing unit parallel computing technology. The TPI-S curve reveals a pair of thresholds of S indicating mild or severe RAS. The TPI at S = 0 represents the pressure improvement following a successful stenting therapy. Six patient cases with a total of 6 aortic and 12 renal arteries are studied. The computed blood pressure waveforms have good agreements with the in vivo measured ones and the systolic pressure is statistical equivalence to the in-vivo measurements with p < .001. Uncertainty quantification provides the reliability of the computed pressure through the corresponding 95% confidence interval. The severity assessments of RAS in four cases are consistent with the medical practice. The preliminary results inspire a more sophisticated investigation for real medical insights of the new index. This computational concept can be applied to other arterial stenoses such as iliac stenosis. Such a noninvasive and patient-specific hemodynamic index has the potential to aid in the clinical decision-making of interventional treatment with reduced medical cost and patient risks.

The Predictive Ability of the Renal Resistive Index and Its Relationship to Duplex Ultrasound Waveform Propagation in the Aorta and Renal Arteries.

BACKGROUND: The objective is to investigate whether calculating the PPI (Pulse Pressure Index) and the RRI (Renal Resistive Index) using routinely collected Duplex ultrasound waveforms data obtained from the aorta and renal artery correlates and predicts renal function, and determine whether RRI is affected by the presence of a renal artery stenosis. METHODS: The records of 965 patients were evaluated. The RRI or pulsatility index of the aorta, renal artery, hilum, cortex, and medulla were measured with concurrent glomerular filtration rate GFR, Cr, PPI, and HR measurements, among which 75 patients had a 24-hour urine measured for CrCl, and 32 patients had aortic pulse pressure index (API) calculated from the central aortic pressure measured with applanation tonometry. The propagation of the pulsatility was evaluated by Analysis of Variance (ANOVA). The correlation coefficient (r) and the linear regression coefficient of determination R-squared (R2) were determined. The effects of a renal artery stenosis were evaluated with a paired t-Test comparing the RRI in 192 patients where only one side had a renal artery stenosis greater than 60%. RESULTS: The pulsatility indexes and RRIs progressively decreases and are statistically distinct by ANOVA from the aorta to the renal cortex (P = 7.26 × 10-125). CrCl correlates with the PPI, cortex RRI and medulla RRI with r equal to -0.34, -0.23 and -0.42 (P < 0.05). GFR correlates with the PPI, cortex RRI and medulla RRI with r equal to -0.15, -0.12, and -0.20 (P < 0.0001). Cr correlates with the PPI, cortex RRI and medulla RRI with r equal to 0.09, 0.12, and 0.14 (P < 0.005). The CrCl, GFR and Cr were not statistically correlated with the HR. On univariate and multivariate analysis, the R2 predictive value for PPI, cortex RRI and medulla RRI for CrCl, GFR and Cr were all less than 0.2 (P < 0.05). The cortex and medulla RRI were correlated with the API with r = 0.63 (P < 0.001). The R2 predictive value of the PPI for the cortex and medulla RRI was 0.41 and 0.28 (P < 0.001), respectively. On paired t-Test analysis renal artery stenosis had no effect on the RRI (P = 0.78). CONCLUSIONS: The RRI is calculated based on velocity waveform propagation where pulsatility slowly decreases in a series of elastic vessels. While CrCl, GFR and Cr do correlate with the PPI, cortex RRI and medulla RRI, the R2 coefficient of determination for these correlations demonstrate that they are poor predictors of renal function. Renal artery stenosis did not have any effect on the RRI.

Computational methods to automate the initial interpretation of lower extremity arterial Doppler and duplex carotid ultrasound studies.

BACKGROUND: Lower extremity arterial Doppler (LEAD) and duplex carotid ultrasound studies are used for the initial evaluation of peripheral arterial disease and carotid stenosis. However, intra- and inter-laboratory variability exists between interpreters, and other interpreter responsibilities can delay the timeliness of the report. To address these deficits, we examined whether machine learning algorithms could be used to classify these Doppler ultrasound studies. METHODS: We developed a hierarchical deep learning model to classify aortoiliac, femoropopliteal, and trifurcation disease in LEAD ultrasound studies and a random forest machine learning algorithm to classify the amount of carotid stenosis from duplex carotid ultrasound studies using experienced physician interpretation in an active, credentialed vascular laboratory as the reference standard. Waveforms, pressures, flow velocities, and the presence of plaque were input into a hierarchal neural network. Artificial intelligence was developed to automate the interpretation of these LEAD and carotid duplex ultrasound studies. Statistical analysis was performed using the confusion matrix. RESULTS: We extracted 5761 LEAD ultrasound studies from 2015 to 2017 and 18,650 duplex carotid ultrasound studies from 2016 to 2018 from the Indiana University Health system. The results showed the ability of artificial intelligence algorithms and method, with 97.0% accuracy for predicting normal cases, 88.2% accuracy for aortoiliac disease, 90.1% accuracy for femoropopliteal disease, and 90.5% accuracy for trifurcation disease. For internal carotid artery stenosis, the accuracy was 99.2% for predicting 0% to 49% stenosis, 100% for predicting 50% to 69% stenosis, 100% for predicting >70% stenosis, and 100% for predicting occlusion. For common carotid artery stenosis, the accuracy was 99.9% for predicting 0% to 49% stenosis, 100% for predicting 50% to 99% stenosis, and 100% for predicting occlusion. CONCLUSIONS: The machine learning models using LEAD data, with the collected blood pressure and waveform data, and duplex carotid ultrasound data with the flow velocities and the presence of plaque, showed that novel machine learning models are reliable in differentiating normal from diseased arterial systems and accurate in classifying the extent of vascular disease.

Urgent Endovascular Repair of an Anterior Tibial Artery Aneurysm: Case Report and Literature Review.

True aneurysms of the anterior tibial artery are rare with less than 20 published reports in the literature. We report an urgent endovascular repair of a true anterior tibial artery aneurysm in a patient with Ehlers-Danlos type IV, vascular type. This approach resulted in an uneventful recovery without the elevated risks associated with open vascular repair in the setting of connective tissue disorder. Continuous follow-up in the subsequent 4 years has demonstrated durability and efficacy of the original intervention.

Treatment of a traumatic aortic bifurcation injury with an iliac branch endoprosthesis.

We present the case of a 62-year-old man who sustained a traumatic distal aortic injury associated with an adjacent lumbar vertebral body fracture resulting from a 20-ft fall. Given the site of injury, an iliac artery branched endograft was deployed off-label to preserve the aortic bifurcation and cover a limited amount of healthy aorta to preserve the collaterals. The procedure was successful, with no intraoperative complications or evidence of an endoleak. The aortic bifurcation and distal iliac arteries remained widely patent by computed tomography angiography at the follow-up examination without evidence of sequelae.

Perioperative and Long-term Results of Zenith Fenestrated Aortic Repair in Women.

BACKGROUND: Inferior perioperative outcomes for women receiving major vascular surgery are well established in the literature in multiple arterial distributions. Therefore, this study was completed to determine the perioperative and durability results associated with women undergoing complex aortic reconstruction using the Zenith Fenestrated platform (ZFEN; Cook Medical, Bloomington, IN). METHODS: A retrospective review of a fenestrated endovascular aortic repair (FEVAR) database capturing all ZFENs performed at our institution between October 2012 and March 2019 was completed. Preoperative, intraoperative, perioperative, and follow-up outcomes were tabulated for females and compared with their male counterparts. RESULTS: Within our study period, 136 total ZFEN procedures were performed; of which, 20 devices (14.7%) were implanted in women. Intraoperatively, we observed a higher rate of estimated blood loss (660.0 mL vs. 311.6 mL, P < 0.01) and resultant need for transfusion (1.4 vs. 0.3 units, P < 0.01) in women despite a similar frequency of brachial (5.0% vs. 7.8%, P > 0.99) and femoral artery cutdowns (55.0% vs. 49.1%, P = 0.81). Operative (295.7 min vs. 215.7 mins, P < 0.01) and fluoroscopy (84.3 vs. 58.7 min, P < 0.01) times were also significantly higher in females than those in their male counterparts. In the perioperative (30-day) period, we observed significantly longer length of stay (5.6 days vs. 3.3 days, P = 0.03) and continued need for transfusion (50% vs. 9.5%, P < 0.01) in women. Statistical trends favoring men were also noted with respect to all-cause mortality, reintervention, visceral stent thrombosis, renal failure, acute kidney injury, and respiratory failure. After a mean follow-up of nearly 2 years, we found no differences in late all-cause or aneurysm-related mortality, major adverse cardiovascular events, or need for reinterventions. CONCLUSIONS: The implantation of ZFEN in females is significantly more difficult than that in their male counterparts and may result in increased perioperative, but not necessarily long-term, complications.

Perioperative and 1-year transcarotid revascularization outcomes in symptomatic patients.

OBJECTIVE: Previously published results of carotid revascularization with both transfemoral stenting and endarterectomy have demonstrated inferior perioperative stroke and death outcomes in neurologically symptomatic patients compared with those without symptoms. This study was completed to establish the real-world, symptom-based perioperative and follow-up outcomes for transcarotid artery revascularization (TCAR). METHODS: An institutional retrospective review of all TCARs performed outside of clinical trial regulations from 2016 to 2019 was completed. Eligible patients were classified as symptomatic or not based on a history of a unilateral neurologic deficit attributable to an extracranial carotid artery lesion within the previous 180 days. Univariate analysis consisting of Fisher's exact and Student t-tests, as appropriate, were performed between cohorts. Kaplan-Meier analysis was completed to estimate the stroke-free survival at 1 year postoperatively. RESULTS: Within the investigational period, 167 patients (85 symptomatic) qualified for study inclusion. Baseline demographics were roughly equivalent, although symptomatic patients were more likely to be female (28.0% vs 9.4%; P < .01). Procedures in symptomatic patients were associated with higher estimated blood loss (41 mL vs 58 mL; P = .04) and operative time (67 minutes vs 75 minutes; P = .06). We did not find an increased incidence of macroscopic debris in the filter of symptomatic patients after stent deployment. For symptomatic patients, we observed a perioperative (30-day) ipsilateral stroke risk of 1.2% (vs 2.4% in asymptomatic patients; P > .99), a myocardial infarction risk of 0% (vs 0%; P > .99), and a mortality risk of 4.9% (vs 0%; P = .06). Most deaths occurred after procedure-related discharge; as such, in-hospital (from index TCAR) mortality in symptomatic patients was 1.2%. The four perioperative deaths observed in our population were secondary to hemorrhagic stroke, acute on chronic congestive heart failure (n = 2), and unknown causes in the last patient. At 1 year after the procedure, 114 patients (54 symptomatic) had available data. In addition to the perioperative risks, in symptomatic patients we observed a rate of reintervention of 0% (vs 0%; P > .99), ipsilateral stroke of 3.7% (vs 0%; P = .22), >50% in-stent restenosis of 1.9% (vs 0%; P = .47), stent thrombosis of 3.7% (vs 0%; P = .22), and all-cause mortality of 13.0% (vs 10.0%; P = .77). Last, no difference was noted with respect to the 1-year stroke-free survival (P = .17) by Kaplan-Meier estimates. CONCLUSIONS: In this institutional series of patients undergoing TCAR, we found that symptomatic patients have a similar perioperative risk of stroke and myocardial infarction as asymptomatic patients. However, we did observe a strong statistical trend suggesting a higher mortality risk in symptomatic patients. There was no difference between cohorts with respect to 1-year stroke-free survival.

An unusual arteriovenous malformation involving the cervical vessels treated with endovascular repair.

We present an unusual and complex arteriovenous malformation involving the vertebral artery, subclavian artery, and internal jugular vein in a 31-year-old man with no history of trauma or catheterization. The repair was done using endovascular techniques to minimize complications from nerve or vascular injury. The massively dilated jugular vein has remained diminished in size and the patient has remained asymptomatic at 8 months. We discuss the occurrence of this rare malformation as well as treatment options along with their risks and benefits.

Aggressive Surveillance Is Needed to Detect Endoleaks and Junctional Separation between Device Components after Zenith Fenestrated Aortic Reconstruction.

BACKGROUND: Junctional separation and resulting type IIIa endoleak is a well-known problem after EVAR (endovascular aneurysm repair). This complication results in sac pressurization, enlargement, and eventual rupture. In this manuscript, we review the incidence of this late finding in our experience with the Cook Zenith fenestrated endoprosthesis (ZFEN, Bloomington, IN). METHODS: A retrospective review was performed of a prospectively maintained institutional ZFEN fenestrated EVAR database capturing all ZFENs implanted at a large-volume, academic hospital system. Patients who experienced junctional separation between the fenestrated main body and distal bifurcated graft (with or without type IIIa endoleak) at any time after initial endoprosthesis implantation were subject to further evaluation of imaging and medical records to abstract clinical courses. RESULTS: In 110 ZFENs implanted from October 2012 to December 2017 followed for a mean of 1.5 years, we observed a 4.5% and 2.7% incidence of clinically significant junctional separation and type IIIa endoleak, respectively. Junctional separation was directly related to concurrent type Ib endoleak in all 5 patients. Three patients presented with sac enlargement. One patient did not demonstrate any evidence of clinically significant endoleak and had a decreasing sac size during follow-up imaging. The mean time to diagnosis of modular separation in these patients was 40 months. Junctional separation was captured in surveillance in 2 patients and reintervened upon before manifestation of endoleak. However, the remaining 3 patients completed modular separation resulting in rupture and emergent intervention in 2 and an aortic-related mortality in the other. CONCLUSIONS: Junctional separation between the fenestrated main and distal bifurcated body with the potential for type IIIa endoleak is an established complication associated with the ZFEN platform. Therefore, we advocate for maximizing aortic overlap during the index procedure followed by aggressive surveillance and treatment of stent overlap loss captured on imaging.

Outcomes associated with a transcarotid artery revascularization-centered protocol in high-risk carotid revascularizations using the ENROUTE neuroprotection system.

OBJECTIVE: This investigation describes the perioperative and early follow-up results associated with transcarotid artery revascularization (TCAR) in patients not participating in the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure II (ROADSTER-2) registry using the ENROUTE neuroprotection system (ENPS; Silk Road Medical, Sunnyvale, Calif). METHODS: A retrospective review was performed capturing all TCAR/ENPS procedures in patients deemed to be at high risk for complications after traditional carotid endarterectomy. All patients enrolled in the ROADSTER-2 registry were excluded, leaving only those treated outside trial regulations for analysis. Preoperative demographics, intraoperative variables, and perioperative and follow-up outcomes were abstracted and reported herein. RESULTS: From December 2015 to January 2018, there were 75 carotid arteries treated at our institution. All interventions were performed on carotid arteries that were symptomatic with ≥50% stenosis (46.7%) or asymptomatic with ≥80% stenosis (53.3%) by duplex ultrasound and computed tomography angiography. Technical success in our series was 97.3% (73/75), with treatment failures attributed to one case of common carotid artery dissection and another secondary to stent maldeployment in the external carotid artery. Perioperative (30-day) ipsilateral stroke rate was 2.7% (n = 2), myocardial infarction incidence was 0%, and mortality rate was 2.7% (n = 2). We did not observe any cranial nerve injuries. After a mean follow-up of 8.0 ± 6.7 months, no carotid stents required reintervention. However, we noted one instance of minor (<50%) in-stent stenosis and one asymptomatic stent thrombosis. One additional ipsilateral stroke was observed on follow-up, probably from a cardiac source. CONCLUSIONS: We report that dynamic reverse-flow TCAR using the ENPS continues to be safe, feasible, and efficacious with minimal risks of postoperative stroke, myocardial infarction, and mortality outside of ROADSTER-2 regulations.

Fenestrated endovascular aneurysm repair-induced acute kidney injury does not result in chronic renal dysfunction.

OBJECTIVE: Acute kidney injury (AKI) is a common physiologic complication after fenestrated endovascular aneurysm repair (FEVAR). This investigation was initiated to determine the unknown impact of post-FEVAR AKI on long-term renal function after index hospital discharge. METHODS: A retrospective review was performed of an institutional FEVAR database capturing preoperative, intraoperative, and postoperative variables related to the implantation of consecutive Zenith Fenestrated endografts (ZFEN; Cook Medical, Bloomington, Ind) between October 2012 and April 2018. AKI in this study was bimodally defined as qualification by either Risk, Injury, Failure, Loss of kidney function, and End-stage (RIFLE) criteria or a postoperative serum creatinine (sCr) concentration increase of 0.5 mg/dL from baseline. Glomerular filtration rate (GFR) was calculated using the validated Modification of Diet in Renal Disease (MDRD) study equation. RESULTS: During the study period, 120 FEVARs were performed at our institution. Twenty-four (20%) patients exhibited postoperative AKI by our established definitions. Two in-hospital deaths occurred in the AKI cohort compared with none in the remaining FEVARs (P = .04). Four (16.7%) AKI patients required perioperative (<30-day) renal replacement therapy, three of whom were successfully weaned before discharge. FEVARs uncomplicated by AKI exhibited no differences in sCr concentration from baseline to 1-month, 6-month, 1-year, and 2-year follow-up (mean, 1.8 ± 1.4 years). In contrast, patients exhibiting AKI experienced an sCr concentration increase of 57.1% (P = .01) at 1 month after the procedure. This elevation decreased to 14.3% (P = .35) at 6 months after the procedure and was maintained at baseline values at 1- and 2-year office visits (follow-up, 1.3 ± 1.5 years). A similar pattern of gradual recovery during follow-up was also observed with respect to calculated GFR. CONCLUSIONS: AKI is common after FEVAR but rarely results in permanent renal dysfunction as both sCr concentration and GFR return to baseline by 6 months after the procedure.

Adjunctive visceral artery chimney in patients undergoing Zenith Fenestrated aortic repair.

OBJECTIVE: Visceral artery chimneys have been employed as an adjunct to endovascular aneurysm repair (EVAR) to treat short-neck infrarenal and juxtarenal aortic aneurysms for more than two decades. With the widespread introduction of fenestrated endovascular aneurysm repair by the Food and Drug Administration-approved Zenith Fenestrated endograft (ZFEN; Cook Medical, Bloomington, Ind) to the United States in 2012, clinicians gained the ability to apply the chimney technique to these custom devices for difficult anatomy. The purpose of this report was to demonstrate feasibility and to provide evidence on the performance of chimneys for the treatment of complex juxtarenal aneurysms that could not be adequately treated with ZFEN alone. METHODS: A retrospective analysis was performed of a prospectively maintained institutional ZFEN database capturing 110 fenestrated endovascular aneurysm repairs from October 2012 to January 2018 to identify patients undergoing a concomitant visceral artery chimney. All patients with <12 months of follow-up were excluded from further analysis. Demographic, anatomic, intraoperative, perioperative, and follow-up characteristics were tabulated and analyzed. RESULTS: Six patients met criteria and were included in this investigation. They were universally male with a mean age of 76.2 years at the time of ZFEN/chimney. Chimneys were placed in a total of six visceral arteries (n = 1 per patient) consisting of three renal arteries, two celiac arteries, and one accessory renal artery. Mean estimated blood loss and operative time were 283 mL and 298 minutes, respectively. Technical success was achieved in all cases. Two small type IA "gutter" endoleaks were detected early; both spontaneously resolved on follow-up. We observed no instances of chimney migration, stenosis, or thrombosis perioperatively or on follow-up. Two reinterventions were performed in these six patients; these consisted of a repeated renal stent for ostial stenosis at a main body fenestration and a common femoral artery endarterectomy and patch angioplasty for an access-related common femoral artery occlusion. CONCLUSIONS: Use of ZFEN in conjunction with a singular chimney is safe, feasible, and durable in patients with difficult anatomy who do not meet instructions for use as demonstrated in this limited series.

Use of the Zenith Fenestrated platform to rescue failing endovascular and open aortic reconstructions is safe and technically feasible.

OBJECTIVE: Proximal neck dilation is a serious long-term complication directly causing the failure of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) of abdominal aortic aneurysms. However, the implantation of a fenestrated device presents the opportunity for proximal extension of the aortic reconstruction into a healthy segment while maintaining patency of the visceral vessels. The objective of this investigation was to report perioperative and follow-up outcomes using the Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, Ind) aortic stent system in salvaging previous aortic repairs undergoing type IA endoleak or aneurysmal degeneration of the proximal neck. METHODS: We performed a retrospective review of a prospectively maintained institutional database capturing all fenestrated EVAR (FEVAR) cases with the ZFEN platform. Fenestrated cases were classified as primary FEVAR or reoperative FEVAR (rFEVAR) after previous EVAR or OSR. Cohort comparisons were performed using Fisher exact tests and Student t-tests for categorical and continuous variables, respectively. RESULTS: Between October 2012 and March 2017, a total of 103 patients diagnosed with abdominal aortic aneurysm with an inadequate proximal seal zone for traditional EVAR were treated with ZFEN. In 12 patients, FEVAR was performed as a reoperation after previous EVAR (n = 6) or OSR (n = 6). The indications for rFEVAR were proximal neck dilation (>55 mm) after OSR (n = 6), type IA endoleak after EVAR (n = 5), and proximal neck dilation after EVAR without endoleak (n = 1). No difference in ability to achieve technical success was observed between primary FEVAR and rFEVAR (97.8% vs 100%; P = 1.00). In addition, there were no differences in estimated blood loss (363 vs 500 mL; P = .25) and intraoperative use of contrast material (97.3 vs 104.0 mL; P = .55). However, a significant increase in fluoroscopy time (61.1 vs 79.8 minutes; P = .04), radiation exposure (415.9 vs 606.3 rad; P = .02), and operative time (228.4 vs 287.6 minutes; P = .03) in the rFEVAR cohort was observed. In the 30-day perioperative period, there were no significant differences with regard to mortality (2.2% vs 0%; P = 1.0), major adverse cardiovascular events (5.5% vs 0%, P = 1.0), and stent-related adverse events (2.2% vs 0%; P = 1.0). There were no differences in rates of perioperative (5.5% vs 0%; P = 1.0) or follow-up reintervention after a mean follow-up duration of 20.8 months (18.6% vs 25.0%; P = .70). CONCLUSIONS: FEVAR with the ZFEN platform of failed and failing aortic reconstructions due to disease progression is safe and feasible without increased morbidity and mortality in select patients. These preliminary results support the inclusion of ZFEN as a treatment option for aortic reintervention.

Institutional experience with the Zenith Fenestrated aortic stent graft.

OBJECTIVE: The Zenith Fenestrated (ZFEN; Cook Medical, Bloomington, Ind) aortic stent graft system was approved for commercial use by the Food and Drug Administration in April 2012. We report our single-center experience of 100 consecutive patients treated with the ZFEN platform from October 2012 to March 2017. METHODS: A retrospective review of our prospectively maintained fenestrated endovascular aneurysm repair (FEVAR) database at a tertiary care academic institution located in the Midwest United States was performed for descriptive analysis. All continuous variables are reported as a mean ± standard deviation and compared using two-sided Student t-tests. Categorical variables were compared using two-sided Fisher exact tests. RESULTS: All but one of the procedures were elective in nature. Overall intraoperative characteristics included a mean blood loss (estimated blood loss) of 388 ± 385 mL, fluoroscopy time of 63 ± 30 minutes, radiation dose of 437 ± 272 rad, contrast material volume of 99 ± 36 mL, and operative time of 236 ± 87 minutes. Average number of visceral arteries stented was 2.1 ± 0.5. Technical success was achieved in 98% of the patients. Statistically significant (P < .05) improvement in estimated blood loss (2.1-fold) was observed in the second half of our series. Interestingly, no improvements were made in terms of fluoroscopy time, radiation exposure, contrast material use, or operative time. However, procedural difficulty increased in the last half by number of visceral arteries stented as a surrogate (1.9 vs 2.2; P < .05). Mean length of stay was 3.6 ± 4.3 days. Perioperative mortality at 30 days was 2%. Perioperative morbidity included a 5% incidence of any bowel ischemia, 1% of spinal cord ischemia, 3% of renal failure requiring hemodialysis, 1% of stroke, and 4% of myocardial infarction. Average follow-up was 1.7 ± 1.4 years. Reintervention during the follow-up phase was 20%. Of the 209 visceral arteries stented, we noted 6 instances of stent thrombosis, 6 of kinking or stenosis, and 1 of stent fracture in follow-up. Endoleak, most commonly type II, was present or could not be excluded in 15% of all FEVARs at last available computed tomography angiography. CONCLUSIONS: In our experience, FEVAR with the ZFEN system continues to be safe and effective. There is a significant rate of reintervention observed, and close monitoring is fundamental to maintaining good clinical results.

A vascular laboratory protocol for improving and managing after-hours suspected acute deep venous thrombosis.

This study reviews the clinical and workforce impact of a suggested protocol designed for the management of suspected acute deep venous thrombosis (DVT) in patients seen after standard vascular laboratory business hours. The protocol included the use of Wells score, D-dimer and a single dose of therapeutic anticoagulant to defer venous duplex ultrasound (VDU) testing until routine business hours unless contraindicated. Information was collected on medical history, physical exam and the timing of any diagnostic studies and treatment provided. Over 15% of studies done after-hours were deemed unnecessary by our protocol and in every individual the results were negative for an acute DVT. There were no adverse events from a one-time dose of anticoagulant. Limiting emergency VDU coverage to evaluate for acute DVT based on a management protocol can eliminate unnecessary after-hours VDU testing without having a negative impact on patient care.

Prospective, multicenter experience with the Ventana Fenestrated System for juxtarenal and pararenal aortic aneurysm endovascular repair.

OBJECTIVE: This study assessed preliminary results of the Ventana Fenestrated System (Endologix, Irvine, Calif) as an off-the-shelf integrated device for juxtarenal aortic aneurysm (JAA) or pararenal aortic aneurysm (PAA) endovascular repair. METHODS: From November 2010 to April 2012, seven centers enrolled 31 patients with JAAs or PAAs in an international clinical trial of the Ventana Fenestrated System. Clinical and laboratory evaluations were done predischarge and at 1 month, with continuing follow-up through 5 years. Core laboratory computed tomography imaging assessments were performed at 1 month and at each subsequent follow-up. RESULTS: Patients (mean age, 73 years; 90% male) presented with mean aneurysm sac diameter of 6.0 cm. One patient with a short, reversed tapered infra-superior mesenteric artery (SMA) neck was enrolled under a protocol waiver. Among the 31 patients, one of five Ventana device models was used to preserve main renal arteries, the SMA, and celiac arteries; 20 patients (65%) received the same Ventana device (aligned fenestrations, 28-mm diameter). Median fluoroscopy and procedure times were 49 and 197 minutes, respectively; median hospital length of stay was 3.0 days. The 1-month clinical success rate was 94% (29 of 31), with no perioperative mortality. One intervention on day 26 was done to resolve limb kink/occlusion. A type IA endoleak and renal occlusion secondary to procedural device damage led to a reintervention on day 52 and dialysis at 5 months. During follow-up to 23 months, three non-aneurysm-related deaths occurred. No aneurysm rupture or conversion to open repair has occurred. One late migration with endoleak and covered renal stent fracture/occlusion occurred at 8 months in the patient with a short, reverse tapered infra-SMA neck performed under a protocol waiver, which was managed successfully with bilateral renal bypasses and endovascular repair of the endoleak. Another patient underwent late endovascular interventions to resolve bilateral renal stenosis. CONCLUSIONS: The multicenter experience of the Ventana Fenestrated System supports its safety and early-term to midterm effectiveness for the endovascular repair of JAAs and PAAs. This off-the-shelf integrated system permits endovascular treatment of JAAs or PAAs; however, further expanded clinical experience and longer-term follow-up are needed to more fully assess this device system.

Femoral arterial access management for endovascular aortic aneurysm repair: evolution and outcome.

Endovascular repair of abdominal and thoracic aortic aneurysms (AAAs and TAAs, respectively) has become the standard of care for anatomically appropriate patients. All the devices developed to date for endograft repair of AAAs and TAAs are deployed through relatively large (12F to 24F) sheaths. Traditionally, this access has required arterial exposure with open cut down, but with the development of suture-mediated arterial closure devices and decreasing profile of delivery sheaths of endografts, there is an increasing trend toward percutaneous endovascular repair of aortic aneurysms. This is an effective and safe approach in a select group of patients. Ultrasound guidance ensures that access is obtained proximal to the common femoral artery bifurcation. The procedure should be performed in a sterile operating room environment, and the physicians performing endovascular repair should be experienced in open arterial exposure, should the closure device fail to close the arteriotomy.