Daniel E. Kendrick

Prevalence of Bovine Aortic Arch Configuration in Adult Patients with and without Thoracic Aortic Pathology.

BACKGROUND Bovine aortic arch (BA) occurs in approximately 15-35% of the US population and is regarded as a clinically insignificant, normal variant. The aim of this study was to assess the prevalence of types I (type I bovine arch [T1BA], common origin of innominate and/or left common carotid artery) and II (type II bovine arch [T2BA], left common carotid originating from innominate) bovine arch in patients with and without thoracic aortic pathology. METHODS We retrospectively reviewed all serial computed tomography images (n = 817) performed at our institution over 4 months to determine the overall prevalence of BA. Thoracic aorta and/or arch vessels were visualized, with images read by certified radiologists. A separate analysis compared a series of 156 consecutive patients with thoracic pathology (dissection or aneurysm ≥ 4.0 cm), from a 25-month period, with 757 control patients without pathology from the original sample. Statistical analysis included a chi-squared contingency table. RESULTS Analysis revealed a bovine arch prevalence of 31.1% (n = 254), including 14.9% T1BA and 16.2% T2BA. Patients with thoracic aortopathy (n = 156) had aortic dissection (n = 26) or aneurysm (n = 130). These patients were older and had an increased prevalence of hypertension, hyperlipidemia, and aortic calcification. In addition, there was increased prevalence of T2BA in the pathology group (23.7%) compared with controls (15.9%; P = 0.03). T1BA was not significantly different between groups (11.5% vs. 14.9%; P = 0.59). When thoracic disease was stratified by pathology type, T2BA occurred more frequently in patients with thoracic aortic aneurysm (24.6% vs. 15.9%; P = 0.04). BA trended upward, in patients with thoracic aortic dissection (42.3% vs. 30.8%; P = 0.28). CONCLUSIONS Our analyses revealed a prevalence of bovine arch of 31% in our patient population. BA occurred more frequently in patients with thoracic aortopathy than controls. Therefore, patients with BA may be associated with higher levels of thoracic aortic pathology and may benefit from increased clinical vigilance.

The end stage of dialysis access: femoral graft or HeRO vascular access device.

BACKGROUND Maintaining and establishing vascular access in end-stage renal disease (ESRD) patients is complicated when they are poor candidates for traditional upper extremity access. Our objective was to compare our experience with 2 alternative dialysis accesses, the femoral arteriovenous graft (fAVG) and the Hemodialysis Reliable Outflow (HeRO), in patients with limited remaining options. METHODS A single institution, retrospective review of ESRD patients with fAVG or HeRO placed between May 2009 and February 2013 was performed. Adult patients were selected by reviewing all arteriovenous grafts placed at a single institution. Patient demographics, medical history, access characteristics, and outcomes were recorded from both institutional and dialysis center databases. Data were evaluated using Fishers exact test, unpaired t-test for continuous variables, log-rank test, and univariate analysis. RESULTS A total of 56 accesses in 43 unique patients met these criteria: 35 fAVG and 21 HeRO; with 1 HeRO patient lost immediately to follow-up. Clinical variables were similar except the HeRO group had more diabetic patients (60% HeRO, 22.9% fAVG; P = 0.01). The average number of years on hemodialysis was 7.0 ± 1.0 for fAVG and 5.7 ± 0.9 for HeRO (P = 0.41). Primary patency was 40.5%, 18.7%, and 14.9% for fAVG and 29.0%, 29.0%, and 0% for HeRO at 6 months, 12 months, and 2 years (P = 0.67), respectively. Assisted primary patency was also similar, with 43.8%, 29.4%, and 13.8% for fAVG and 34.8%, 34.8%, and 17.4% for HeRO at 6 months, 12 months, and 2 years (P = 0.81), respectively. Secondary patency was 62.6%, 50.6%, 19.3% for fAVG and 68.0%, 53.5%, 38.3% for HeRO at 6 months, 12 months, and 2 years (P = 0.69), respectively. Average number of interventions to maintain patency for fAVG was 1.1 ± 1.47 and 1.65 ± 2.52 for HeRO (P = 0.35). Infectious complications occurred in 29% of fAVG and 15% of HeRO (P = 0.33). CONCLUSIONS Patients who received either fAVG or HeRO experience poor access patency. ESRD patients who receive either of these procedures appear to be at the end stage of available access options.

Comparative occupational radiation exposure between fixed and mobile imaging systems.

OBJECTIVE Endovascular intervention exposes surgical staff to scattered radiation, which varies according to procedure and imaging equipment. The purpose of this study was to determine differences in occupational exposure between procedures performed with fixed imaging (FI) in an endovascular suite compared with conventional mobile imaging (MI) in a standard operating room. METHODS A series of 116 endovascular cases were performed over a 4-month interval in a dedicated endovascular suite with FI and conventional operating room with MI. All cases were performed at a single institution and radiation dose was recorded using real-time dosimetry badges from Unfors RaySafe (Hopkinton, Mass). A dosimeter was mounted in each room to establish a radiation baseline. Staff dose was recorded using individual badges worn on the torso lead. Total mean air kerma (Kar; mGy, patient dose) and mean case dose (mSv, scattered radiation) were compared between rooms and across all staff positions for cases of varying complexity. Statistical analyses for all continuous variables were performed using t test and analysis of variance where appropriate. RESULTS A total of 43 cases with MI and 73 cases with FI were performed by four vascular surgeons. Total mean Kar, and case dose were significantly higher with FI compared with MI. (mean ± standard error of the mean, 523 ± 49 mGy vs 98 ± 19 mGy; P < .00001; 0.77 ± 0.03 mSv vs 0.16 ± 0.08 mSv, P < .00001). Exposure for the primary surgeon and assistant was significantly higher with FI compared with MI. Mean exposure for all cases using either imaging modality, was significantly higher for the primary surgeon and assistant than for support staff (ie, nurse, radiology technologist) beyond 6 feet from the X-ray source, indicated according to one-way analysis of variance (MI: P < .00001; FI: P < .00001). Support staff exposure was negligible and did not differ between FI and MI. Room dose stratified according to case complexity (Kar) showed statistically significantly higher scattered radiation in FI vs MI across all quartiles. CONCLUSIONS The scattered radiation is several-fold higher with FI than MI across all levels of case complexity. Radiation exposure decreases with distance from the radiation source, and is negligible outside of a 6-foot radius. Modern endovascular suites allow high-fidelity imaging, yet additional strategies to minimize exposure and occupational risk are needed.

Endovascular Simulation Leads to Efficiency and Competence in Thoracic Endovascular Aortic Repair Procedures

OBJECTIVE Endovascular interventions such as thoracic endovascular aortic repair (TEVAR) have largely replaced invasive open procedures, and have been demonstrated to be effective in treating patients. Our study used endovascular simulation to assess the effect of TEVAR rehearsal on surgical trainees at different levels in training. DESIGN Participants were oriented on an endovascular simulator and subsequently a simulated TEVAR was performed during 4 separate sessions over a 1-month period. Metrics included total procedure/fluoroscopy time and volume of contrast used. Likert scale qualitative analysis evaluated participant׳s skills involving major procedural steps. Analysis of data across cohorts included 1-way analysis of variance, Kruskal-Wallis, and paired t-tests. SETTING All data were collected at University Hospitals-Case Medical Center, Cleveland, OH. PARTICIPANTS In all, 12 trainees in 3 cohorts (student, surgery resident postgraduate year [PGY] 1-3, surgery resident/fellow PGY 4-7, n = 4 each) were recruited. RESULTS All trainees reduced total procedure time (mean = 537 ± 148 vs 269 ± 66s, first session vs fourth, P < 0.05, CI: 195-341) and fluoroscopy time (mean = 201 ± 74 vs 110 ± 37s, P < 0.05, CI: 51-132) with TEVAR case progression. The student cohort decreased procedure time from 551 ± 84s to 313 ± 65s (P < 0.05, CI: 189-287) whereas PGYs 1 to 3 decreased procedure time from 591 ± 149s to 264 ± 29s (P < 0.05, CI: 113-541). Use of contrast decreased over time, but the difference was not significant. Participants acquired proficiency after a few runs in most steps of the procedure. The average qualitative score for all groups combined improved significantly (P < 0.03). PGY 4 to 7 trainees had higher technical scores but this was not statistically significant. The initial gap in junior vs senior trainee performance narrowed after a few practice sessions in all aspects evaluated. CONCLUSIONS TEVAR rehearsal on an endovascular simulator can reduce overall procedure and fluoroscopy time, independent of trainee skill level or experience, as well as improve subjective measures of technical success. Further studies are needed to compare simulator performance to outcomes in live cases.

Dextran or Saline Can Replace Contrast for Intravascular Optical Coherence Tomography in Lower Extremity Arteries

Purpose: To examine the hypothesis that alternative flush media could be used for lower extremity optical coherence tomography (OCT) imaging in long lesions that would normally require excessive use of contrast. Methods: The OPTical Imaging Measurement of Intravascular Solution Efficacy (OPTIMISE) trial was a single-center, prospective study (ClinicalTrials.gov identifier NCT01743872) that enrolled 23 patients (mean age 68±11 years; 14 men) undergoing endovascular intervention involving the superficial femoral artery. Four flush media (heparinized saline, dextran, carbon dioxide, and contrast) were used in succession in random order for each image pullback. Quality was defined as ≥270° visualization of vessel wall layers from each axial image. Mean proportions (± standard deviation) of image quality for each flush medium were assessed using 1-way analysis of variance and are reported with the 95% confidence intervals (CI). Results: Four OCT catheters failed, leaving 19 patients who completed the OCT imaging protocol; from this cohort, 51 highest quality runs were selected for analysis. Average vessel diameter was 3.99±1.01 mm. OCT imaging allowed 10- to 15-μm resolution of the lumen border, with diminishing quality as vessel diameter increased. Plaque characterization revealed fibrotic lesions. Mean proportions of image quality were dextran 87.2%±12% (95% CI 0.81 to 0.94), heparinized saline 74.3%±24.8% (95% CI 0.66 to 0.93), contrast 70.1%±30.5% (95% CI 0.52 to 0.88), and carbon dioxide 10.0%±10.4% (95% CI 0.00 to 0.26). Dextran, saline, and contrast provided better quality than carbon dioxide (p<0.001). Conclusion: OCT is feasible in peripheral vessels <5 mm in diameter. Dextran or saline flush media can allow lesion characterization, avoiding iodinated contrast. Carbon dioxide is inadequate for peripheral OCT imaging. Axial imaging may aid in enhancing durability of peripheral endovascular interventions.

Simulation of carotid artery stenting reduces training procedure and fluoroscopy times

Objective: Outcomes from carotid artery stenting (CAS) are related to experience and technical expertise of the operator. Simulation of CAS may enhance clinical proficiency. We interrogated the impact of endovascular simulation of CAS procedures in operators who are at various stages of training. Methods: Twelve trainees (students [n = 4]; junior surgery residents, postgraduate year [PGY] 1‐3 [n = 4]; and senior surgery residents or fellows, PGY 4‐7 [n = 4]) were apprised of characteristics of an endovascular simulator and CAS procedures. This was followed by four independent sessions that were assessed for objective measures including procedure and fluoroscopy times and contrast agent use. A qualitative analysis grading steps of CAS by two observers using a Likert scale was performed. One‐way analysis of variance and paired t‐tests were employed for data analysis. Results: For all participants (n = 12), procedure times (mean, 920 ± 279 seconds for the first session vs 454 ± 156 seconds for the fourth session; P < .01; confidence interval [CI], 315‐621) and fluoroscopy cumulative times (mean, 421 ± 230 seconds for the first session vs 222 ± 102 seconds for the fourth session; P < .01; CI, 78‐285) decreased with progression of cases. Students and PGY 1‐3 residents decreased their procedure times significantly in comparison of initial and final sessions (P < .05 and P < .01, respectively). For all groups, fluoroscopy cumulative times were reduced, and this decrement was significant in the PGY 1‐3 cohort (mean, 444 ± 8 seconds for the first session vs 265 ± 51 seconds for the fourth session; P < .01; CI, 81‐276). Initial CAS procedure times were significantly different between groups (P < .05), but this was observed to resolve by the final case at study completion. Qualitatively, the Likert scores of students and PGY 1‐3 residents significantly improved with case repetition, specifically in the following steps: (1) cannulation of common carotid artery and (2) sizing and deployment of embolic protection device. Senior operators (PGY 4‐7) demonstrated consistently better performance overall with minimal change in scoring with case repetition. Conclusions: Practice leads to improvements in endovascular simulator procedure and fluoroscopy times, especially for more novice trainees. Initial operator performance gaps can be approximated with a few sessions to expected proficiency. Incorporation of endovascular simulators in residency training may assist in shortening the learning curve in rarer endovascular procedures.

Evaluating strategies for reducing scattered radiation in fixed-imaging hybrid operating suites

Objective: High‐resolution fixed C‐arm fluoroscopic systems allow high‐quality endovascular imaging but come at a cost of greater scatter radiation generation and increased occupational exposure for surgeons. The purpose of this study was to evaluate the efficacy of two methods in reducing scattered radiation exposure. Methods: There were 164 endovascular cases analyzed in three phases. In phase 1 (P1), baseline radiation exposure was calculated. In phase 2 (P2), staff used real‐time radiation dose monitoring (dosimetry badges [RaySafe; Unfors, Hopkinton, Mass]). In phase 3 (P3), a software imaging algorithm was installed that reduced radiation (EcoDose software; Philips Healthcare, Best, The Netherlands). Results: A total of 72 cases in P1, 34 cases in P2, and 58 cases in P3 were analyzed. Total mean dose‐area product decreased across each phase, with statistical significance achieved for P1 vs P3 (mean ± standard error of the mean, 186,173 ± 16,754 mGy/cm2 vs 121,536 ± 11,971 mGy/cm2; P = .002) and P2 vs P3 (171,921 ± 26,276 mGy/cm2 vs 121,536 ± 11,971 mGy/cm2; P = .04), whereas total mean fluoroscopy time did not significantly differ across any phase. The radiation exposure to the primary operator did not change significantly from P1 to P2 but fell significantly in P3 (0.08 ± 0.02 mSv vs 0.03 ± 0.01 mSv; P = .02). The addition of dose reduction software had the most impact on endovascular aneurysm repair, with reductions in median room dose (P = .03) and primary operator exposure (P2 vs P3; 0.19 ± 0.04 mSv vs 0.03 ± 0.02 mSv; P < .01). Conclusions: Dose reduction software may be an effective technique to lower radiation exposure. Implementation of system‐based strategies to reduce radiation is needed to reduce lifetime occupational radiation exposure for endovascular staff and to improve patient safety.

Cost awareness decreases total percutaneous coronary intervention procedural cost: The SHOPPING (Show How Options in Price for Procedures Can Be Influenced Greatly) trial

We initiated the SHOPPING Trial (Show How Options in Price for Procedures can be InflueNced Greatly) to see if percutaneous coronary intervention (PCI) procedures can be performed at a lower cost in a single institution.

Characterizing tissue perfusion after lower extremity intervention using two-dimensional color-coded digital subtraction angiography

Objective Digital subtraction angiography (DSA) of the peripheral arterial vasculature provides lumenographic information but only a qualitative assessment of blood flow. The ability to quantify adequate tissue perfusion of the lower extremities would enable real‐time perfusion assessment during DSA of patients with peripheral arterial disease (PAD). In this study, we used a novel real‐time imaging software to delineate tissue perfusion parameters in the foot in PAD patients. Methods Between March 2015 and June 2016, patients (N = 31) underwent lower extremity angiography using a two‐dimensional perfusion (2DP) imaging protocol (Philips Healthcare, Andover, Mass). Of the 31 enrolled patients, 16 patients received preintervention and postintervention DSA images (18 angiograms), while contrast agent injection settings and the position of the foot, catheter, and C‐arm were kept constant. The region of interest for perfusion measurements was taken at the level of the medial malleolus. Perfusion parameters included arrival time (AT) of contrast material, wash‐in rate (WIR), time to peak (TTP) contrast intensity, and area under the curve (AUC). Results Patients (mean age, 67 years; male, 61%) undergoing 2DP had limbs classified as Rutherford class 3 (n = 9 limbs), class 4 (n = 11), and class 5 (n = 14) ischemia with a mean ankle‐brachial index of 0.63. For the whole cohort, median (interquartile range) AT measured 5.20 (3.10‐7.25) seconds; WIR, 61.95 (43.53‐86.43) signal intensity (SI)/s; TTP, 3.80 (2.88‐4.50) seconds; peak intensity, 725.00 (613.75‐1138.00) SI; and AUC, 12,084.00 (6742.80‐17,059.70) SI*s. A subset of patients had 2DP performed before and after intervention (n = 18 cases). A detectable improvement in SI and two‐dimensional flow parameters was seen after intervention. Average AT of contrast material to the region of interest shortened after intervention with percentage decrease of 30.1% ± 49.1%, corresponding decrease in TTP of 17.6% ± 24.7%, increase in WIR of 68.8% ± 94.2% and in AUC of 10.5% ± 37.6%, decrease in mean transit time of 18.7% ± 28.1%, and increase in peak of 34.4% ± 42.2%. Conclusions The 2DP imaging allows measurement of blood flow in real time as an adjunct to DSA. The AT may be the most sensitive marker of perfusion change in the lower extremity. Quantitative thresholds based on 2DP hold promise for immediate treatment effectiveness assessment in patients with PAD.

Carotid Occlusion Leads to Higher Annual Healthcare Costs than Carotid Stenosis

Objectives: Direct iliac access with or without conduit can be used in endovascular abdominal aortic aneurysm repair (EVAR) when anatomy is unfavorable for femoral access. The impact of this technical approach has not been adequately studied. We evaluated the perioperative outcomes in patients who required direct iliac access or conduit for EVAR and compared it with those who did not. Methods: Patients undergoing EVAR with and without iliac access/conduits were identified in the 2005 to 2012 National Surgical Quality Improvement Program data sets. Perioperative morbidity and mortality were assessed by 5:1 propensity matched (on age, gender, functional status, comorbidities, urgency, anesthesia use and relative operative duration) groups and multivariable analyses. Results: There were 15,082 patients undergoing infrarenal EVAR with 147 (1%) with (41) and without (107) conduit placement. Patients treated with iliac conduit/access were more likely to be female (25.9% vs 17.8%, P 1⁄4 .02) and have peripheral arterial disease (12.9% vs 5.5%, P < .01). There was no difference in age (74.5 6 8.4 conduit vs 74.9 6 8). On multivariate analysis the iliac conduits/access group had higher mortality (odds ratio [OR] 2.7; 95% confidence interval [CI], 1.4-5.4; P # .01), major complications, including cardiac arrest/ myocardial infarction (OR, 2.9; 95% CI, 1.3-6.3; P # .01) and pulmonary complications (OR, 2.1; 95% CI, 1.2-3.9; P 1⁄4 .01), and postoperative length of stay (means ratio, 1.3; 95% CI, 1.1-1.4; P # .01). No difference was noted for renal and wound complications. Matched analysis based on demographics, comorbidities, and operative time showed that iliac conduit/access patients had higher perioperative mortality (6.8% vs 2.3%, P < .01), cardiac (4.8% vs 1%, P < .01), pulmonary (8.8% vs 3.4%), and bleeding complications (10.2% vs 4.6%, P 1⁄4 .02). Conclusions: Our results demonstrate that the use of direct iliac access or conduits in EVAR is associated with increased mortality and major morbidity. In situations where anatomy mandates the use iliac access, surgeons should consider other options, including using lower profile devices or open aneurysm repair.