Faculty Bibliography

BACKGROUND:Mannitol is often administered during open juxtarenal or suprarenal aortic surgery to prevent ischemic injury to the kidneys. Prior evidence evaluating the benefits of intraoperative mannitol in reducing ischemia/reperfusion injury is conflicting and largely based on small, retrospective series. The aim of this study was to evaluate the effect of mannitol in preventing postoperative hemodialysis in patients undergoing open abdominal aortic aneurysm (AAA) repair where proximal control involved temporary renal ischemia. METHODS:The Society for Vascular Surgery Quality Initiative database was queried for all patients undergoing elective open AAA repair between 2003 and 2020. Patients were included in the current analysis if the proximal aortic clamp was placed above at least one renal artery. Chronic kidney disease (CKD) was defined as Cr > 1.8 mg/dL. Primary end points were 30-day major morbidity (myocardial infarction, respiratory complications, lower extremity or intestinal ischemia, and the need for temporary or permanent hemodialysis) and mortality. Comparisons were made between the mannitol and nonmannitol cohorts and stratified by the presence of preexisting CKD. RESULTS:During the study period, 4,156 patients underwent elective open AAA repair requiring clamp placement more than one (32.7%) or both (67.3%) renal arteries; 182 patients (4.4%) had preexisting CKD. Overall, 69.8% of patients received mannitol during their surgery. Mannitol was more frequently used in cases involving clamp placement above both renal arteries (70.3%) than one renal artery (61.5%). While prolonged ischemia time (more than 40 min) was associated with a higher risk of postoperative dialysis in patients without CKD, it was not significant in patients with baseline CKD. On a univariate analysis, mannitol use in patients with CKD was associated with a lower risk of postoperative dialysis (P = 0.005). This remained significant on a multivariate analysis (P = 0.008). Mannitol use did not appear to confer renal protective effects in patients without baseline CKD. CONCLUSIONS:Mannitol use was associated with a decreased risk of need for postoperative hemodialysis in patients with CKD undergoing suprarenal aortic clamping for open aneurysm repair. In appropriately selected patients, particularly those with underlying renal insufficiency, mannitol may confer a renal protective effect in open repair of pararenal AAA requiring suprarenal clamping.

OBJECTIVES/OBJECTIVE:Endovascular aortic aneurysm repair (EVAR) has become the standard of care treatment for abdominal aortic aneurysms (AAA) in the modern era. While numerous devices exist for standard infrarenal AAA repair, fenestrated endovascular aneurysm repair (fEVAR) offers a minimally invasive alternative to traditional open repair in patients with short infrarenal necks. Over time, aortic neck dilation can occur leading to loss of proximal seal, endoleaks, and AAA sac growth. This study analyzes aortic remodeling following EVAR versus fEVAR and further evaluates whether fEVAR confers a benefit in terms of sac shrinkage. METHODS:A retrospective review of prospectively collected data on 120 patients undergoing EVAR was performed: 30 patients were treated with fEVAR (Cook Zenith© Fenestrated) and 90 patients were treated with EVAR devices (30 with each Medtronic Endurant ©, Gore Excluder ©, and Cook Zenith ©). Demographic data were recorded, and anatomic measurements were taken for each patient pre-operatively, 30 days post-operatively, and at the longest point of follow-up using three-dimensional reconstruction software. RESULTS:There were no significant differences in demographics data between the 4 groups. fEVAR was used more often in aortas with large necks and irregular morphology (p= 0.004). At the time of longest follow up, the suprarenal aorta encompassing 5, 10, and 15mm above the lowest renal artery (ALRA) dilated the most for fEVAR versus all EVAR groups. Despite this, the infrarenal segment tended to increase by the least, or even regress, for fEVAR compared to all EVAR groups, and was associated with the overall greatest proportion of sac shrinkage for the fEVAR group compared to Medtronic, Gore, and Cook devices, respectively (-13.90% vs. -5.75% vs. -2.31% vs. -4.68%, p=0.025). CONCLUSIONS:Compared to EVAR, patients treated with fEVAR had greater suprarenal dilation over time, consistent with an overall greater burden of disease in the proximal native aorta. However, the infrarenal segment dilated significantly less over time in the fEVAR group compared to all EVAR groups, suggesting that fEVAR may stabilize the infrarenal neck, promoting positive sac remodeling, as evidenced by the greatest degree of decrease in largest AAA diameter in the fEVAR group.

OBJECTIVES/OBJECTIVE:In patients deemed high risk for carotid endarterectomy (CEA) who are indicated for treatment of carotid artery stenosis (CAS), transcarotid artery revascularization (TCAR) has been demonstrated as a safe and effective alternative to trans-femoral carotid artery stenting (TF-CAS). Compared to CEA, where approx. 12% of patients undergoing awake intervention do not tolerate internal carotid artery (ICA) clamping, only 1-2% of patients were observed to have intolerance to flow reversal during TCAR based on data from the ROADSTER1/2 trials. This study reviewed awake interventions from those trials to assess factors associated with intolerance to flow reversal and review how those cases were managed. METHODS:This is a retrospective review of prospectively collected data from Reverse Flow Used During Carotid Artery Stenting Procedure (ROADSTER) multicenter trial along with the subsequent post-approval (ROADSTER-2) trial. The subset of patients from both trials undergoing awake TCAR was analyzed to compare demographics, procedural details, and anatomic factors between patients who did and did not experience intolerance to reversal of flow to assess for predisposing factors. Patients were deemed intolerant to flow reversal at the discretion of the operator, often related to changes in completion of neurologic tasks, hemodynamic stability, or patient reported symptoms. RESULTS:103 patients from ROADSTER and 194 patients from ROADSTER-2 underwent TCAR under local/regional anesthesia. Of these, 8 patients had intolerance to flow reversal, though all cases were successfully completed. While intra-operative hemodynamic data was only available for 5 of the 8 intolerant patients, none experienced hypotension. 4 cases were completed under low flow reversal, 3 cases were successfully weaned from low to high flow over several minutes, and 1 case required general anesthesia. No significant association was found between intolerance to flow reversal and comorbidities including diabetes mellitus (DM), hypertension (HTN), hyperlipidemia (HLD), congestive heart failure (CHF), prior MI or angina, pre-op CAS-related symptoms, prior stroke, prior CAS or CEA, prior neck radiation, tandem stenosis, high cervical stenosis, or hostile neck (tables 1, 2). A trend towards significance was seen with chronic obstructive pulmonary disease (COPD) and contralateral carotid artery occlusion (p= 0.086 and 0.139, respectively). CONCLUSIONS:Despite intolerance to flow reversal, TCAR cases were successfully completed by adjusting reversal-of-flow rate and do not typically require conversion to GETA. While factors contributing to intolerance of flow reversal during TCAR remain poorly understood, this study identified a trend towards significance with an association of pre-existing COPD and contralateral carotid artery occlusion. Given the low number of patients who experienced this issue, a larger sample size is required to better elucidate these trends.

OBJECTIVE:Contemporary commercially available endovascular devices for the treatment of abdominal aortic aneurysm (AAA) include standard endovascular aortic repair (sEVAR) or fenestrated EVAR (fEVAR) endografts. However, aortic neck dilatation (AND) can occur in nearly 25% of patients following EVAR, resulting in loss of proximal seal with risk of aortic rupture. AND has not been well characterized in fEVAR, and direct comparisons studying AND between fEVAR and sEVAR have not been performed. This study aims to analyze AND in the infrarenal and suprarenal aortic segments, including seal zone, and quantify sac regression following fEVAR implantation compared to sEVAR. METHOD/METHODS:A retrospective review of prospectively collected data on 20 consecutive fEVAR patients (Cook Zenith® Fenestrated) and 20 sEVAR (Cook Zenith®) patients was performed. Demographic data, anatomic characteristics, procedural details, and clinical outcome were analyzed. Pre-operative, post-operative (1 month), and longest follow-up CT scan at an average of 29.3 months for fEVAR and 29.8 months for sEVAR were analyzed using a dedicated 3D workstation (iNtuition, TeraRecon Inc, Foster City, California). Abdominal aortic aneurysm neck diameter was measured in 5 mm increments, ranging from 20 mm above to 20 mm below the lowest renal artery. Sub-analysis comparing the fEVAR to the sEVAR group at 12 months and at greater than 30 months was performed. Standard statistical analysis was done. RESULTS:Demographic characteristics did not differ significantly between the two cohorts. The fEVAR group had a larger mean aortic diameter at the lowest renal artery, shorter infrarenal aortic neck length, increased prevalence of nonparallel neck shape, and longer AAA length. On follow-up imaging, the suprarenal aortic segment dilated significantly more at all locations in the fEVAR cohort, whereas the infrarenal aortic neck segment dilated significantly less compared to the sEVAR group. Compared to the sEVAR cohort, the fEVAR patients demonstrated significantly greater positive sac remodeling as evident by more sac diameter regression, and elongation of distance measured from the celiac axis to the most cephalad margin of the sac. Device migration, endoleak occurrence, re-intervention rate, and mortalities were similar in both groups. CONCLUSION/CONCLUSIONS:Compared to sEVAR, patients undergoing fEVAR had greater extent of suprarenal AND, consistent with a more diseased native proximal aorta. However, the infrarenal neck, which is shorter and also more diseased in fEVAR patients, appears more stable in the post-operative period as compared to sEVAR. Moreover, the fEVAR cohort had significantly greater sac shrinkage and improved aortic remodeling. The suprarenal seal zone in fEVAR may result in a previously undescribed increased level of protection against infrarenal neck dilatation. We hypothesize that the resultant decreased endotension conferred by better seal zone may be responsible for a more dramatic sac shrinkage in fEVAR.

OBJECTIVE:Transcarotid artery revascularization (TCAR) seems to be a safe and effective alternative to carotid endarterectomy (CEA) and transfemoral carotid artery stenting (TF-CAS). The TCAR system represents a paradigm shift in the management of carotid artery stenosis with potential for a significant decrease in periprocedural morbidity. However, as with CEA or TF-CAS, TCAR is associated with infrequent complications related to user technical error, most of which are preventable. Our goal is to describe these low-frequency events, and to provide guidelines for avoiding them. METHODS:The U.S. Food and Drug Administration (FDA) requires that all medical device manufacturers create a system for receiving, reviewing, and evaluating complaints (Code 21 of Federal Regulations 820.198). Silk Road Medical, Inc (Sunnyvale, Calif), has established a process by which all feedback, including complaints that may not meet FDA criteria, is captured and stored in a database for detailed analysis. More than 13,300 cases have been performed; submitted complaints were reviewed for incidents of serious injury and periprocedural complications, above and beyond the device-related events that must be reported to the FDA. RESULTS:A total of 13,334 patients have undergone TCAR worldwide between early 2011 and December 2019 using the SilkRoad device. Reported complications included 173 dissections (1.4% overall rate) of the common carotid artery at the access point, of which 22.5% were managed without intervention or with medical therapy alone and 24.3% were converted to CEA (considered failing safely). Errors in the location of stent deployment occurred in 16 cases (0.13%), with the most common site being the external carotid artery (75%). One wrong side carotid artery stent was placed in a patient with a high midline pattern of the bovine arch. Cranial nerve injury was reported in 11 cases (0.08%), only one of which persisted beyond 3 months. There have been three reported pneumothoraces and one reported chylothorax. Many of these errors can be recognized and prevented with careful attention to detail. CONCLUSIONS:In high-risk patients requiring treatment for carotid artery stenosis, TCAR has been proven as an alternative to TF-CAS with an excellent safety profile. As with CEA or TF-CAS, this procedure has the potential for infrequent complications, often as a result of user technical error. Although significant, these events can be avoided through a review of the collective experience to date and recognition of potential pitfalls, as we have described.

Objective: Aortic neck dilation (AND) can occur in nearly 25% of patients after EVAR, resulting in loss of proximal seal and aortic rupture. Fenestrated endovascular aneurysm repair (FEVAR) affords increased treatment options for patients with shorter infrarenal aortic necks; however, AND has not been well characterized in these patients. This study sought to compare AND in patients undergoing FEVAR vs standard endovascular aneurysm repair (EVAR).
Method(s): Retrospective review was conducted of prospectively collected data of 20 consecutive FEVAR patients (Cook Zenith fenestrated; Cook Medical, Bloomington, Ind) and 20 EVAR patients (Cook Zenith). Demographic and anatomic characteristics, procedural details, and clinical outcome were analyzed. Preoperative, 1-month postoperative, and longest follow-up computed tomography scans were analyzed using a dedicated three-dimensional workstation. Abdominal aortic aneurysm (AAA) neck diameter was measured in 5-mm increments from the lowest renal artery. Standard statistical analysis was performed.
Result(s): Demographic characteristics did not differ significantly between the two cohorts. The FEVAR group had larger mean aortic diameter at the lowest renal artery, shorter infrarenal aortic neck length, increased prevalence of nonparallel neck shape, and longer AAA length (Table). On follow-up imaging, the suprarenal aortic segment dilated significantly more at all suprarenal locations in the FEVAR cohort, whereas the infrarenal aortic neck segment dilated significantly less compared with the EVAR group (Table). The FEVAR group demonstrated significantly greater sac regression vs the EVAR group. Positive aortic remodeling, as evidenced by increased distance from the celiac axis to the most cephalad margin of the AAA, occurred to a more significant degree in the FEVAR cohort. Device migration, endoleak occurrence, and need for reintervention were similar in both groups.
Conclusion(s): Compared with EVAR, patients undergoing FEVAR had greater extent of suprarenal AND, consistent with a more diseased native proximal aorta. However, the infrarenal neck, which is shorter and also more diseased in FEVAR patients, appears more stable in the postoperative period compared with EVAR cases. Moreover, the FEVAR cohort had significantly greater sac shrinkage and improved aortic remodeling. The suprarenal seal zone in FEVAR may confer a previously undescribed increased level of protection against infrarenal neck dilation and lessen endotension, resulting in more rapid and dramatic sac shrinkage and contributing to a more durable aortic repair. [Formula presented]
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Objectives/UNASSIGNED:Mortality rates in intubated coronavirus disease 2019 patients remain markedly elevated. Some patients develop sudden refractory hypercapnia and hypoxemia not explained by worsening pulmonary parenchymal disease. This case series highlights clinical findings and management of coronavirus disease 2019 patients with refractory hypercapnia despite maximal/optimal ventilatory support. Hypercapnia could not be explained by worsening lung disease or other common factors, and thus, a pulmonary vascular etiology was suggested. The pillars of management were targeted to improve pulmonary vascular patency via aggressive anticoagulation and support right ventricular function. Data Sources/UNASSIGNED:Four consecutive patients with confirmed coronavirus disease 2019 infection with sudden hypercapnia and hypoxemia were included. Data Synthesis/UNASSIGNED:removal was discontinued in three patients over the ensuing 3 weeks, and one patient was discharged home. Conclusions/UNASSIGNED:We speculate that thromboinflammation with pulmonary microvasculature occlusion leads to a sudden increase in dead space and shunt resulting in severe hypercapnia and hypoxemia in coronavirus disease 2019 patients. Early identification of these physiologic and clinical biomarkers could trigger the institution of therapies aiming to reverse the hypercoagulable state and support right ventricular function.

OBJECTIVE:To provide an evidence-based overview of endovenous laser ablation and describe its role as an effective and durable technique for the management of superficial venous insufficiency. METHODS:The published literature on the treatment of varicose veins using endovenous laser ablation was reviewed. The literature search focused on the history of endovenous laser ablation, its safety and durability, known complications, and differences in outcomes based on the iterations of fiber type and laser wavelength. RESULTS:Treatment safety and efficacy of endovenous laser ablation appear to be based on the amount of energy administered over a defined distance, or the linear endovenous energy density. The ideal linear endovenous energy density varies with the laser wavelength and fiber-type. Post-operative pain and bruising may be reduced by the use of higher wavelength fibers or the use of radial or jacket-tip fibers as compared to bare-tip fibers. The incidence of endothermal heat-induced thrombosis remains low and has declined with increasing experience. Reports have demonstrated a greater than 90% technical success rate with saphenous endovenous laser ablation, long-term durability of ablation, and commensurate improvement in quality of life. CONCLUSIONS:Endovenous laser ablation is a safe and durable treatment option for the management of incompetent superficial and perforator veins of the lower extremities. As an endothermal technology, it remains a key component of the standard of care for the treatment of chronic venous insufficiency.

Objective: In patients deemed high risk for carotid endarterectomy (CEA) who are indicated for treatment of carotid artery stenosis (CAS), transcarotid artery revascularization (TCAR) has been demonstrated to be a safe and effective alternative to transfemoral CAS. Compared with CEA, in which approximately 12% of patients undergoing awake intervention do not tolerate internal carotid artery clamping, only 1% to 2% of patients were observed to have intolerance to flow reversal during TCAR based on data from the Safety and Efficacy Study for Reverse Flow Used During Carotid Artery Stenting Procedure (ROADSTER) 1 and 2 trials. This study reviewed awake interventions from those trials to assess factors associated with intolerance to flow reversal and to review how those cases were managed.
Method(s): This is a retrospective review of prospectively collected data from the ROADSTER multicenter trial along with the subsequent postapproval (ROADSTER 2) trial. The subset of patients from both trials undergoing awake TCAR was analyzed to compare demographics, procedural details, and anatomic factors between patients who did and did not experience intolerance to reversal of flow to assess for predisposing factors. Patients were deemed intolerant to flow reversal at the discretion of the operator, often related to changes in completion of neurologic tasks, hemodynamic stability, or patient-reported symptoms.
Result(s): There were 103 patients from ROADSTER and 194 patients from ROADSTER 2 who underwent TCAR under local/regional anesthesia. Of these, eight patients had intolerance to flow reversal, although all cases were successfully completed. Four cases were completed under low-flow reversal, three cases were successfully weaned from low to high flow during several minutes, and one case required general anesthesia. No significant association was found between intolerance to flow reversal and comorbidities including diabetes mellitus, hypertension, hyperlipidemia, congestive heart failure, prior myocardial infarction or angina, preoperative CAS-related symptoms, prior stroke, prior CAS or CEA, prior neck irradiation, tandem stenosis, high cervical stenosis, or hostile neck (Tables I and II). A trend toward significance was seen with chronic obstructive pulmonary disease (P =.086) and contralateral carotid artery occlusion (P =.139).
Conclusion(s): Despite intolerance to flow reversal, most cases were successfully completed by adjusting reversal of flow rate and did not require conversion to general endotracheal anesthesia. Whereas factors contributing to intolerance of flow reversal during TCAR remain poorly understood, this study identified a trend toward significance with an association of pre-existing chronic obstructive pulmonary disease and contralateral carotid artery occlusion. Given the low number of patients who experienced this issue, a larger sample size is required to better elucidate these trends. [Formula presented] [Formula presented]
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