Leveraging Artificial Intelligence to Optimize the Care of Peripheral Artery Disease Patients

Peripheral artery disease is a major atherosclerotic disease that is associated with poor outcomes such as limb loss, cardiovascular morbidity, and death. Artificial intelligence (AI) has seen increasing integration in medicine, and its various applications can optimize the care of peripheral artery disease (PAD) patients in diagnosis, predicting patient outcomes, and imaging interpretation. In this review, we introduce various AI applications such as natural language processing, supervised machine learning, and deep learning, and we analyze the current literature in which these algorithms have been applied to PAD.

Medical Management of Traumatic Vertebral Artery Injury Is Safe Regardless of the Severity of Injury

BACKGROUND

Management of traumatic vertebral artery injury (VAI) remains under debate. Current consensus reserves surgical or endovascular management for high-grade injury in order to prevent stroke. We sought to evaluate the factors that influence posterior fossa stroke outcomes following traumatic VAI.

METHODS

A search of the prospectively maintained PROOVIT trauma registry of patients older than 18 years of age with a diagnosis of VAI was performed at a level 1 trauma center from 2013 to 2019. Patient demographics, type of injury, the timing of presentation, Biffl Classification of Cerebrovascular Injury Grade score, medical management, procedural interventions, and stroke outcomes were analyzed.

RESULTS

VAIs were identified in 66 trauma patients were identified out of 14,323 patients entered into the PROOVIT registry. The dominant mechanism was blunt injury (91.5% vs. 8.5%, blunt versus penetrating). Nine patients presented with symptomatic ipsilateral posterior circulation strokes visible on imaging. The average Biffl classification grade was similar between the stroke and nonstroke groups (2.0 vs. 1.5; P = 0.39). The average injury severity score (ISS) between stroke and nonstroke groups was also similar (9.0 vs. 14.0; P = 0.35). All 9 patients in the stroke group had magnetic resonance imaging verification of their infarct within an average of 21.2 hr from presentation. In the stroke group, 1 patient underwent diagnostic angiography but had no intervention. In the nonstroke group, all were treated with medical management alone and none underwent vertebral artery intervention. During a mean follow-up of 14.5 months, no patients experienced a new neurological deficit.

CONCLUSIONS

The severity of VAI by Biffl grading and ISS are not associated with ischemic stroke at presentation following VAI. Medical management of VAI appears safe regardless of Biffl and ISS staging in this trauma population. Neurological changes related to embolic stroke were generally appreciated on presentation. Conservative medical management was sufficient to protect from secondary neurological deficit regardless of index vertebral injury.

The Order of Operative Repair Does Not Influence Outcomes in Patients with Concomitant Popliteal Artery and Orthopedic Injuries

BACKGROUND

The most challenging lower extremity traumatic injuries involve concomitant vascular and orthopedic injuries with amputation rates approaching 50%. Controversy exists as to how to prioritize the vascular and orthopedic repairs. We reviewed patients with popliteal artery and lower extremity orthopedic injuries to analyze the sequence of the vascular and orthopedic repairs on outcomes.

METHODS

All adult patients with a diagnosis of concomitant popliteal artery and lower extremity fracture or dislocation were identified through a review of an institutional trauma registry performed at a level 1 trauma center from 2014 to 2019. Patient demographics, timing of presentation, injury severity score (ISS), surgical interventions, and limb outcome data were collected and examined. The sequence of operative repairs and factors influencing the operative order were analyzed.

RESULTS

Twenty-nine patients were treated for popliteal artery injuries. Twelve of these 29 patients had concomitant popliteal artery and orthopedic fractures requiring surgical repair. Injury mechanisms included both blunt (50%, 6/12) and penetrating trauma (50%, 6/12); the majority involved femur fractures (58%, 7/12). Vascular repair included arterial bypass (75%, 9/12) or interposition grafts (25%, 3/12). Orthopedic repair included external fixation (83%, 10/12) and open reduction internal fixation (17%, 2/12). Vascular repair was performed first in 7/12 limbs (58%). Patients having vascular repair first had a trend toward lower blood pressure on arrival (P = 0.068). There was no significant difference in emergency department to operating room (OR) time, OR time, ISS, mangled extremity severity score, estimated blood loss, or blood transfusion for the sequence of operative repair. Fasciotomy was nearly ubiquitous, present in 11/12 patients (92%). There were no graft complications related to orthopedic manipulation, and there were no reported limb-length to graft-length discrepancies. Early limb salvage trended lower in the cohort with revascularization first (71% vs. 100%, P = 0.19). Of the remaining limbs available for follow-up, limb salvage at 4.25 years is 100%.

CONCLUSIONS

In this small study of patients with concomitant lower extremity popliteal artery and orthopedic injuries, the order of operative repair does not appear to influence the success of revascularization.

Analysis of Extracranial Cerebrovascular Injuries: Clinical Predictors of Management and Outcomes

BACKGROUND

Optimal management of traumatic extracranial cerebrovascular injuries (ECVIs) remains undefined. We sought to evaluate the factors that influence management and neurologic outcomes (stroke and brain death) following traumatic ECVI.

METHODS

A retrospective review of a single level 1 trauma center's prospectively maintained data registry of patients older than 18 years of age with a diagnosis of ECVI was performed from 2013 to 2019. Injuries limited to the external carotid artery were excluded. Patient demographics, type of injury, timing of presentation, Biffl Classification of Cerebrovascular Injury Grade, Injury Severity Score (ISS), and Abbreviated Injury Scale were documented. Ultimate treatments (medical management and procedural interventions) and brain-related outcomes (stroke and brain death) were recorded.

RESULTS

ECVIs were identified in 96 patients. The primary mechanism of injury was blunt trauma (89.5% vs. 10.5%, blunt versus penetrating), with 70 cases (66%) of vertebral artery injury and 37 cases of carotid artery injury. Treatments included vascular intervention (6.5%) and medical management (93.5%). Overall outcomes included ipsilateral ischemic stroke (29%) and brain death (6.5%). In the carotid group, vascular intervention was associated with higher Biffl grades (mean Biffl 3.17 vs. 2.23; P = 0.087) and decreased incidence of brain death (0% vs. 19%, P = 0.006), with no difference seen in ISS scores. Brain death was associated with higher ISS scores (40.29 vs. 24.17, P = 0.01), lower glascow coma score on arrival (3.57 vs. 10.63, P < 0.001), and increased rates of ischemic stroke (71% vs. 30%, P = 0.025). In the vertebral group, neither Biffl grade nor ISS were associated with treatment or outcomes. Regarding the timing of stroke in ECVI, there was no significant difference in the time from presentation to cerebral infarction between the carotid and vertebral artery groups (24.7 hr vs. 21.20 hr, P = 0.739). After this window, 98% of the ECVI cases demonstrated no further aneurysmal degeneration or new neurological deficits beyond the early time period (mean follow-up 9.7 months).

CONCLUSIONS

Blunt cerebrovascular injuries should be viewed distinctly in the carotid and vertebral territories. In cases of injury to the carotid artery, Biffl grade and ISS score are associated with surgical intervention and neurologic events, respectively; vertebral artery injuries did not share this association. Neurologic deficits were detected in a similar time frame between the carotid artery and the vertebral artery injury groups and both groups had rare late neurologic events.

Presentation and outcomes of thoracic and thoracoabdominal aortic aneurysms in females, existing gaps, and future directions: A descriptive review

Thoracic and thoracoabdominal aortic aneurysms are more common in men. Yet, females often have worse outcomes, fewer interventions, and lower treatment rates. Females have also benefited less from the research and treatment of those diseases than men. Understanding sex- and sex-specific differences in thoracic and thoracoabdominal aortic aneurysms can improve care delivery, reduce disparities, and optimize outcomes for females with thoracic aortic aneurysms and thoracoabdominal aortic aneurysms. The authors reviewed the literature on the presentation and outcomes of thoracic and thoracoabdominal aortic aneurysms in females, discussing the existing gaps and future directions to address them.

Perioperative complications following open or endovascular revascularization for chronic limb-threatening ischemia in the BEST-CLI Trial

OBJECTIVE

Anticipated perioperative morbidity is an important factor for choosing a revascularization method for chronic limb-threatening ischemia (CLTI). Our goal was to assess systemic perioperative complications of patients treated with surgical and endovascular revascularization in the Best Endovascular vs Best Surgical Therapy in Patients with CLTI (BEST-CLI) trial.

METHODS

BEST-CLI was a prospective randomized trial comparing open (OPEN) and endovascular (ENDO) revascularization strategies for patients with CLTI. Two parallel cohorts were studied: Cohort 1 included patients with adequate single-segment great saphenous vein (SSGSV), whereas Cohort 2 included those without SSGSV. Data were queried for major adverse cardiovascular events (MACE-composite myocardial infarction, stroke, death), non-serious (non-SAEs) and serious adverse events (SAEs) (criteria-death/life-threatening/requiring hospitalization or prolongation of hospitalization/significant disability/incapacitation/affecting subject safety in trial) 30 days after the procedure. Per protocol analysis was used (intervention received without crossover), and risk-adjusted analysis was performed.

RESULTS

There were 1367 patients (662 OPEN, 705 ENDO) in Cohort 1 and 379 patients (188 OPEN, 191 ENDO) in Cohort 2. Thirty-day mortality in Cohort 1 was 1.5% (OPEN 1.8%; ENDO 1.3%) and in Cohort 2 was 1.3% (2.7% OPEN; 0% ENDO). MACE in Cohort 1 was 4.7% for OPEN vs 3.13% for ENDO (P = .14), and in Cohort 2, was 4.28% for OPEN and 1.05% for ENDO (P = .15). On risk-adjusted analysis, there was no difference in 30-day MACE for OPEN vs ENDO for Cohort 1 (hazard ratio [HR] 1.5; 95% confidence interval [CI], 0.85-2.64; P = .16) or Cohort 2 (HR, 2.17; 95% CI, 0.48-9.88; P = .31). The incidence of acute renal failure was similar across interventions; in Cohort 1 it was 3.6% for OPEN vs 2.1% for ENDO (HR, 1.6; 95% CI, 0.85-3.12; P = .14), and in Cohort 2, it was 4.2% OPEN vs 1.6% ENDO (HR, 2.86; 95% CI, 0.75-10.8; P = .12). The occurrence of venous thromboembolism was low overall and was similar between groups in Cohort 1 (OPEN 0.9%; ENDO 0.4%) and Cohort 2 (OPEN 0.5%; ENDO 0%). Rates of any non-SAEs in Cohort 1 were 23.4% in OPEN and 17.9% in ENDO (P = .013); in Cohort 2, they were 21.8% for OPEN and 19.9% for ENDO (P = .7). Rates for any SAEs in Cohort 1 were 35.3% for OPEN and 31.6% for ENDO (P = .15); in Cohort 2, they were 25.5% for OPEN and 23.6% for ENDO (P = .72). The most common types of non-SAEs and SAEs were infection, procedural complications, and cardiovascular events.

CONCLUSIONS

In BEST-CLI, patients with CLTI who were deemed suitable candidates for open lower extremity bypass surgery had similar peri-procedural complications following either OPEN or ENDO revascularization: In such patients, concern about risk of peri-procedure complications should not be a deterrent in deciding revascularization strategy. Rather, other factors, including effectiveness in restoring perfusion and patient preference, are more relevant.

Five Year Survival in Medicare Patients Undergoing Interventions for Peripheral Arterial Disease: a Retrospective Cohort Analysis of Linked Registry Claims Data

OBJECTIVE

To justify the up front risks of offering elective interventions for intermittent claudication (IC), patients should have reasonable life expectancy to derive durable clinical benefits. Open surgery for chronic limb threatening ischaemia (CLTI) is maximally beneficial in patients surviving ≥ 2 years. The aim was to assess long term survival after IC and CLTI interventions.

METHODS

In a retrospective cohort analysis, the Vascular Quality Initiative (VQI) registry from 1 January 2010 to 31 May 2021 was queried for peripheral vascular intervention (PVI), infra-inguinal bypasses (IIB), and supra-inguinal bypasses (SIB) for IC and CLTI across 286 US centres. VQI linkage to Medicare insurance claims provided five year survival data. Multivariable analysis identified factors associated with five year mortality.

RESULTS

There were 31 457 PVIs (44.7% IC, 55.3% CLTI), 7 978 IIBs (26.9% IC, 73.1% CLTI), and 2 149 SIBs (50.1% IC, 49.9% CLTI) recorded in the VQI. Among the PVI, IIB, and SIB cohorts, average ages were 75, 73, and 72 years, respectively. Respective five year mortality after PVI for IC and CLTI was 37.2% and 71.1%; after IIB for IC and CLTI it was 37.8% and 60%; and after SIB for IC and CLTI it was 33.8% and 53.8%. On multivariable analysis, across all procedures, end stage renal disease, CLTI, congestive heart failure, anaemia, chronic obstructive pulmonary disease, and prior amputation were independently associated with increased mortality. Pre-admission home living and pre-operative aspirin use were independently associated with decreased mortality.

CONCLUSION

Long term survival in Medicare patients undergoing interventions in VQI centres for peripheral arterial disease is poor. Two thirds of CLTI patients and over one third of IC patients were not alive at five years. Intervening for IC in patients with high mortality risk should be avoided. For CLTI patients identified with decreased survival likelihood, intervention durability may be less important than invasiveness. Pre-operative medical optimisation should always be undertaken.

Bias in artificial intelligence in vascular surgery

Application of artificial intelligence (AI) has revolutionized the utilization of big data, especially in patient care. The potential of deep learning models to learn without a priori assumption, or without prior learning, to connect seemingly unrelated information mixes excitement alongside hesitation to fully understand AI's limitations. Bias, ranging from data collection and input to algorithm development to finally human review of algorithm output affects AI's application to clinical patient presents unique challenges that differ significantly from biases in traditional analyses. Algorithm fairness, a new field of research within AI, aims to mitigate bias by evaluating the data at the preprocessing stage, optimizing during algorithm development, and evaluating algorithm output at the postprocessing stage. As the field continues to develop, being cognizant of the inherent biases and limitations related to black box decision making, biased data sets agnostic to patient-level disparities, wide variation of present methodologies, and lack of common reporting standards will require ongoing research to provide transparency to AI and its applications.

Machine learning and image analysis in vascular surgery

Deep learning, a subset of machine learning within artificial intelligence, has been successful in medical image analysis in vascular surgery. Unlike traditional computer-based segmentation methods that manually extract features from input images, deep learning methods learn image features and classify data without making prior assumptions. Convolutional neural networks, the main type of deep learning for computer vision processing, are neural networks with multilevel architecture and weighted connections between nodes that can "auto-learn" through repeated exposure to training data without manual input or supervision. These networks have numerous applications in vascular surgery imaging analysis, particularly in disease classification, object identification, semantic segmentation, and instance segmentation. The purpose of this review article was to review the relevant concepts of machine learning image analysis and its application to the field of vascular surgery.

Analysis of Traumatic Axillo-Subclavian Vessel Injuries: Endovascular Management is a Viable Option to Open Surgical Reconstruction

BACKGROUND

In traumatic axillo-subclavian vessel injuries, endovascular repair has been increasingly described, despite ongoing questions regarding infection risk and long-term durability. We sought to compare the clinical and safety outcomes between endovascular and surgical treatment of traumatic axillo-subclavian vessel injuries.

METHOD

A search query of the prospectively maintained PROOVIT registry for patients older than 18 years of age with a diagnosis of axillary or subclavian vessel injury between 2014-2019 was performed at a Level 1 Trauma Center. Patient demographics, severity of injury, Mangled Extremity Severity Score (MESS), Injury Severity Score (ISS), procedural interventions, complications, and patency outcomes were collected and analyzed.

RESULTS

Twenty-three patients with traumatic axillo-subclavian vessel injuries were included. There were similar rates of penetrating and blunt injuries (48% vs. 52%, respectively). Eighteen patients (78%) underwent intervention: 11 underwent endovascular stenting or diagnostic angiography; 7 underwent open surgical repair. There was similar severity of arterial injuries between the endovascular and open surgical groups: transection (30% vs. 40%, respectively), occlusion (30% vs. 40%, respectively). The open surgical group had worse initial clinical comorbidities: higher ISS scores (17.0 vs 13.5, p = 0.034), higher median MESS scores (6 vs. 3.5, P = 0.001). The technical success for the endovascular group was 100%. The endovascular group had a lower estimated procedural blood loss (27.5 mL vs. 624 mL, P = 0.03). The endovascular arterial group trended toward a shorter length of hospital stay (5.6 days vs. 27.6 days, P = 0.09) and slightly reduced procedural time (191.0 min vs. 223.5 min, P = 0.165). Regarding imaging follow up (average of 60 days post-discharge), 7 patients (54%) underwent surveillance imaging (5 with duplex ultrasound, 2 with computed tomography angiography CTA) that demonstrated 100% patency. Regardless of ISS or MESS scores, at long term clinical follow up (average of 214 days), there were no limb losses, graft infections or vascular complications in either the endovascular or open surgical group.

CONCLUSIONS

Endovascular treatment is a viable option for axillo-subclavian vessel injuries. Preliminary results demonstrate that endovascular treatment, when compared to open surgical repair, can have similar rates of technical success and long-term outcomes in patency, infection and vascular complications.

Factors Affecting One-Year Outcomes After Major Lower Extremity Amputation in the Vascular Quality Initiative Amputation Registry

INTRODUCTION

Major lower extremity amputation (LEA) results in significant morbidity and mortality. This study identifies factors contributing to adverse long-term outcomes after major LEA.

STUDY DESIGN

Amputations in the Vascular Quality Initiative (VQI) long-term follow-up database from 2012 to 2017 were included. Multivariable logistic regression determined which significant patient factors were associated with 1-year mortality, long-term functional status, and progression to higher level amputation within 1 year.

RESULTS

3440 major LEAs were performed and a mortality rate of 19.9% was seen at 1 year. Logistic regression demonstrated that 1-year mortality was associated with post-op myocardial infarction (MI) (odds ratio (OR) 1.7, CI 1.02-2.97, P = .04), congestive heart failure (CHF) (OR 1.9, confidence interval (CI) 1.56-2.38, P < .001), hypertension (HTN) (OR 1.31, CI 1.00-1.72, P = .05), chronic obstructive pulmonary disease (COPD) (OR 1.36, CI 1.13-1.63, P < .001), and dependent functional status (OR 2.01, CI 1.67-2.41, P < .001). A decline in ambulatory status was associated with COPD (OR 1.36, CI 1.09-1.68, P = .006). Dependent functional status was protective against revision to higher level amputation (OR .18, CI .07-.45, P < .001).

CONCLUSION

In the VQI, 1-year mortality after major LEA is nearly 20% and associated with HTN, CHF, COPD, dependent functional status, and post-op MI. Decreased functional status at 1 year was associated with COPD, and progression to higher level amputation was less likely in patients with dependent functional status.

Health Care System-Wide Analysis Identifies High Radiation Use Factors and Behaviors in Surgery

OBJECTIVE

Usage of radiation among various surgical specialists has not been comprehensively evaluated. A systems-based analysis evaluating intraoperative radiation can help identify high use factors and dose reduction behaviors leading to quality improvement initiatives.

METHODS

A retrospective review of all operative fluoroscopic-guided procedures from 2010 to 2017 from 4 hospitals in a tertiary academic health care system was performed.

RESULTS

One thousand two hundred fifty-two cases were analyzed, and notable trends in metrics including type of equipment, procedures, surgical field, surgical specialty, and dose reduction techniques were demonstrated. Higher radiation exposures were correlated with fixed vs. mobile C-arm usage (1229 mGy vs. 331 mGy, P = .001), abdominal/pelvic procedures (429.2 mGy vs. 274.0 mGy, P = .002), and embolization (2450.6 mGy vs. 328.2 mGy, P = .019). Vascular surgery averaged 40 times higher radiation exposure per patient than other specialties (613.3 mGy vs. 15.6 mGy, P = .001). Notably, vascular surgeons utilized dose reduction techniques less frequently than urology (21.5% vs. 70%, P = .001) but more than neurosurgery and orthopedics (21.5% vs. 1.3% and 0%, P = .001, respectively).

CONCLUSIONS

A system-wide health care analysis identified vascular surgery procedures, use of a fixed C-arm, abdominal/pelvic procedures, and embolization cases as having the highest radiation exposure. These data can serve as baseline information for future quality improvement initiatives regarding fluoroscopy usage by surgeons.

5-Item Modified Frailty Index Predicts Outcomes After Below-Knee Amputation in the Vascular Quality Initiative Amputation Registry

Patient frailty indices are increasingly being utilized to anticipate post-operative complications. This study explores whether a 5-factor modified frailty index (mFI-5) is associated with outcomes following below-knee amputation (BKA). All BKAs in the vascular quality initiative (VQI) amputation registry from 2012-2017 were reviewed. Preoperative frailty status was determined with the mFI-5 which assigns one point each for history of diabetes, chronic obstructive pulmonary disease or active pneumonia, congestive heart failure, hypertension, and nonindependent functional status. Outcomes included 30-day mortality, unplanned return to odds ratio (OR), post-op myocardial infarction (MI), post-op SSI, all-cause complication, revision to higher level amputation, disposition status, and prosthetic use. 2040 BKAs were performed. Logistic regression showed an increasing mFI-5 score that was associated with higher risk of combined complications (OR 1.22, confidence interval [CI] 1.07-1.38, P < .05), 30-day mortality (OR 1.60, CI 1.19-2.16, P < .05), post-op MI (OR 1.79, CI 1.30-2.45, P < .05), and failure of long-term prosthetic use (OR 1.17, CI 1.03-1.32, P < .05). In the VQI, every one-point increase in mFI-5 is associated with an increased risk of 22% for combined complications, 60% for 30-day mortality, nearly 80% for post-op MI, and 17% for failure of prosthetic use in BKA patients. The mFI-5 frailty index should be incorporated into preoperative planning and risk stratification.

True Superficial Temporal Artery Aneurysm Presenting as a Delayed Traumatic Pseudoaneurysm: A Case Report and Review of Literature

A rare case of a true temporal artery aneurysm is presented with review of the literature.

A conservative approach to select patients with ischemic wounds is safe and effective in the setting of deferred revascularization

OBJECTIVE

The Wound, Ischemia, and foot Infection classification system has been validated to predict benefit from inmediate revascularization and major amputation risk among patients with peripheral arterial disease. Our primary goal was to evaluate wound healing, limb salvage, and survival among patients with ischemic wounds undergoing revascularization when intervention was deferred by a trial of conservative wound therapy.

METHODS

All patients with peripheral arterial disease and tissue loss are prospectively enrolled into our Prevention of Amputation in Veterans Everywhere limb preservation program. Limbs are stratified into a validated pathway of care based on predetermined criteria (immediate revascularization, conservative treatment, primary amputation, and palliative care). Limbs allocated to the conservative strategy that failed to demonstrate adequate wound healing and were candidates, underwent deferred revascularization. Rates of wound healing, freedom from major amputation, and survival were compared between patients who underwent deferred revascularization with those who received immediate revascularization by univariate and multivariate analysis.

RESULTS

Between January 2008 and December 2017, 855 limbs were prospectively enrolled into the Prevention of Amputation in Veterans Everywhere program. A total of 203 limbs underwent immediate revascularization. Of 236 limbs stratified to a conservative approach, 185 (78.4%) healed and 33 (14.0%) underwent deferred revascularization (mean, 2.7 ± 2.6 months). The mean long-term follow-up was 51.7 ± 37.0 months. Deferred compared with immediate revascularization demonstrated similar rates of wound healing (66.7% vs 57.6%; P = .33), freedom from major amputation (81.8% vs 74.9%; P = .39), and survival (54.5% vs 50.7%; P = .69). After adjustment for overall Wound, Ischemia, and foot Infection stratification stages, deferred revascularization remained similar to immediate revascularization for wound healing (hazard ratio [HR], 1.5; 95% confidence interval [CI], 0.7-3.2), freedom from major amputation (HR, 0.7; 95% CI, 0.3-1.7) and survival (HR, 1.2; 95% CI, 0.6-2.4).

CONCLUSIONS

Limbs with mild to moderate ischemia that fail a trial of conservative wound therapy and undergo deferred revascularization achieve similar rates of wound healing, limb salvage, and survival compared with limbs undergoing immediate revascularization. A stratified approach to critical limb ischemia is safe and can avoid unnecessary procedures in selected patients.

Native Microchannel Recanalization with Orbital Atherectomy as a Viable Alternative to Failed Standard Recanalization of TASC II D Aortoiliac Occlusive Disease

BACKGROUND

Endovascular treatment of Trans-Atlantic Inter-Society Consensus (TASC) II D aortoiliac lesions is now an accepted form of revascularization. We sought to demonstrate that native microchannel recanalization and orbital atherectomy is a successful recanalization method of TASC II D aortoiliac lesions refractory to standard recanalization techniques.

METHODS

Four consecutive patients from 2016 to 2018 with symptomatic TASC II D aortoiliac occlusive disease prohibitive for open bypass and failed traditional prodding guidewire or device recanalization technique were identified and underwent advanced native microchannel selection and subsequent orbital atherectomy (Cardiovascular Systems, Inc, St Paul, MN). Native microchannels of the calcified lesions were probed and traversed with a 0.014″ wire. The atherectomy crown was tracked over the wire, and orbital atherectomy was initiated with a 1.25 mm crown starting at the lowest revolution and continued until the microchannel is sufficiently large to track a 1.2 mm-balloon for angioplasty. Serial microchannel angioplasty with exchange for stiffer and/or larger profile wires and balloons was achieved until a covered stent could be safely deployed across the target lesion. The kissing stent technique was then used to recreate the aortic bifurcation. A ViperSlide lubricant solution was used in all cases per indication for use. Patients were all heparinized to maintain an activated clotting time of 250. Lesion characteristics, survival, limb salvage, patency, and change in clinical symptoms were also analyzed.

RESULTS

All 4 patients underwent successful native microchannel recanalization and orbital atherectomy of the common iliac artery (CIA). There were no intraoperative ruptures, embolizations, or dissections. All 4 patients presented with unilateral CIA occlusion with contralateral CIA stenosis. The average occlusion lesion length of the CIA was 6.0 cm. The average contralateral stenosis length was 2.3 cm. The kissing stent technique was used in all patients for reconstruction of the aortic bifurcation. At 30 days, all patients had improvement in pain and primary patency of 100%. Long-term follow-up at 21.6 months noted continued improvement in symptoms and primary patency of 75%. The fourth patient died at 4 months from lung cancer with occluded iliac stents by imaging at that time.

CONCLUSIONS

Native microchannel recanalization with subsequent orbital atherectomy is an option in high-risk patients with TASC II D aortoiliac disease who have failed traditional recanalization techniques. Further work in proper patient selection and safe utilization of atherectomy devices in the CIA is needed.

Analysis of Subjective and Objective Screening Techniques as Predictors of Safety for Radial Artery Intervention

BACKGROUND

There is no currently accepted standard in safety evaluation for radial artery intervention. We sought to compare the accuracy of various subjective and objective screening techniques in predicting safety for radial artery intervention.

METHODS

Fifty-four patients in a prospective cohort study at a single institution underwent subjective Allen's test, objective Barbeau test, and several objective hand ultrasound techniques to assess safety for radial artery intervention. These results were then compared to the gold standard of conventional hand angiography to document complete palmar arch. Statistical analysis including sensitivity, specificity, positive predictive values, negative predictive values, and accuracy were calculated.

RESULTS

Compared to hand angiography, the subjective Allen's test and the objective Princeps Pollicis Artery ultrasound demonstrated the comparable levels of sensitivity (100% vs. 96.7%, respectively), specificity (100% vs. 100%, respectively), and accuracy (97.2% vs. 97.1%, respectively). The objective Barbeau test demonstrated similar results (sensitivity of 100%, accuracy of 98.2%) with the exception of a lower specificity (50%).

CONCLUSIONS

There is no currently accepted standard in safety evaluation for radial artery intervention. However, preliminary data suggest that certain subjective and objective techniques such as Allen's testing, Princeps Pollicis artery ultrasound, and Barbeau testing are comparable options in predicting palmar arch patency.

Immediate Carotid Endarterectomy Is Associated with Higher Risk in Symptomatic Patients

BACKGROUND

Guidelines recommend that patients with carotid artery stenosis ≥50% (Sx-CAS) undergo carotid endarterectomy (CEA) within 14 days of symptoms. However, perioperative risks, especially stroke, may be increased when CEA is performed within 48 hours. This study seeks to more fully evaluate the effect of timing of surgery on outcomes for Sx-CAS.

METHODS

All CEAs in the Southern California Vascular Outcomes Improvement Collaborative (SoCal VOICe) from 2012 to 18 were reviewed. Ipsilateral cortical or visual symptoms within 6 months defined Sx-CAS. Timing from symptom occurrence to CEA was classified as immediate (0-2 days), early (3-14 days), or delayed (>14 days). Perioperative stroke, myocardial infarction (MI), and 30-day mortality rates were compared by time to surgery.

RESULTS

Of 2203 CEAs, 436 (20%) were for Sx-CAS (52% stroke, 48% transient ischemic attack). Mean time from symptoms to CEA was 28.3 days (range, 0-172; median, 14 days). Sixty-one cases (14%) were immediate, 166 (38%) early, and 209 (48%) delayed. Perioperative stroke occurred in 2.8% and stroke/MI/30-day mortality in 5.7%. Stroke rate was significantly higher in the immediate group (vs. early and delayed): 8.2%, versus 3.0%, and 0.96%, respectively (P = 0.009). Stroke/MI/30-day mortality was also higher in the immediate group: 13.1%, versus 6.0%, and 3.3%, respectively (P = 0.001). Immediate surgery was associated with greater postoperative events (P = 0.009), and logistic regression confirmed decreased risk of postoperative stroke and stroke/MI/30-day mortality in delayed surgery using immediate surgery as a reference. Wide variability existed among centers in the timing of CEA (immediate-range, 0-50%; delayed-range, 41-83%; P = 0.01).

CONCLUSIONS

In the SoCal VOICe, 52% of patients undergo CEA within 2 weeks of symptoms. Increased stroke rates occur when CEA is performed within 2 days, whereas stroke and death rates are decreased at 3-14 days and beyond. These data support avoidance of immediate CEA. Opportunity exists to standardize timing of CEA for Sx-CAS among SoCal VOICe participants. Further study is required to define the role of immediate CEA.

Direct contrast-enhanced magnetic resonance lymphangiography in the diagnosis of persistent occult chylous effusion leak after thoracic duct embolization

Thoracic duct embolization (TDE) is currently the technique of choice for chylothorax refractory to medical management. Diagnosis and treatment of persistent lymphatic leakage after an initially successful TDE are complicated by inadequate imaging to localize the nidus of the lymphatic leak. Traditional imaging modalities including nuclear medicine lymphoscintigraphy, magnetic resonance lymphangiography, and fluoroscopic lymphangiography lack spatial resolution and dynamic physiologic real-time evaluation. We report a contemporary imaging technique using direct contrast-enhanced magnetic resonance lymphangiography to diagnose an occult chylous leak after TDE.

Debranching of Supra-aortic Vessels via Femoral Artery Inflow for Late Ascending Aortic Rupture

A 56-year-old man with a history of Marfan's syndrome, total arch replacement, descending thoracic endovascular aortic repair, and twice redo sternotomy for pseudoaneurysm repair, presented with a pulsatile chest mass secondary to a contained rupture of the ascending aorta. The patient underwent supra-aortic debranching via the superficial femoral artery and ascending thoracic stent-graft placement under continuous transesophageal echocardiography. Completion angiography demonstrated successful exclusion of the contained rupture. Postoperatively, the patient was neurologically intact, the pulsatile mass resolved, and the bypass grafts remained patent. Chronic respiratory failure and multidrug-resistant pneumonia led to late mortality. This case demonstrates that hybrid repair is effective in the emergent setting of ascending aortic rupture. Debranching of the ascending arch using the superficial femoral artery as inflow is feasible and provides adequate cerebral perfusion despite the length of the bypass. The use of transesophageal echocardiography during stent-graft deployment allows precise device placement in the high-risk area of the ascending aorta proximal to the innominate artery.

Analysis of intraoperative radiation use in vascular surgery: Catalyst for quality improvement in patient and personnel safety

OBJECTIVES

There is paucity in the literature reporting radiation usage analysis in vascular surgery. In the era of endovascular surgeries, analyzing the surgeons' use of radiation in vascular procedures can help establish quality improvement initiatives.

METHODS

A retrospective review was undertaken of intraoperative fluoroscopic-guided vascular surgery procedures at a single institution from 2010 to 2017. Mobile C-arms were utilized to gather the six radiation usage metrics and cases were categorized into 6 anatomic surgical fields and 10 surgical procedure types.

RESULTS

Three hundred and eighteen vascular surgery cases were analyzed and notable trends in all radiation usage metrics were identified both across the surgical field location and type of surgical procedure. The highest cumulative dose was identified in embolization cases with a mean of 932.5 mGy. The highest fluoroscopic time was seen in atherectomies with a mean of 2629.6 s. In terms of surgical field, the highest cumulative does and fluoroscopic time was identified in abdomen/pelvis procedures with a mean of 352.1 mGy and 1186.8 s, respectively. Analysis of dose reduction techniques also demonstrated notable trends.

CONCLUSIONS

There were notable trends in the analyzed radiation usage variables both across the surgical field location and type of surgical procedure. Specifically, cases that involve the abdomen/pelvis, embolization and atherectomy have the highest radiation use. These types of cases can be targeted for future improved dose reduction techniques or staged procedures. This data can serve as baseline information for future quality improvement initiatives for patient and personnel radiation exposure safety.

N(omega)-nitro-L-arginine inhibits inducible HSP-70 via Ca(2+), PKC, and PKA in human intestinal epithelial T84 cells

The nitric oxide (NO) synthase inhibitor N(omega)-nitro-L-arginine (L-NNA) inhibits heat stress (HS)-induced NO production and the inducible 70-kDa heat shock protein (HSP-70i) in many rodent organs. We used human intestinal epithelial T84 cells to characterize the inhibitory effect of L-NNA on HS-induced HSP-70i expression. Intracellular Ca(2+) concentration ([Ca(2+)](i)) was measured using fura-2, and protein kinase C (PKC), and PKA activities were determined. HS increased HSP-70i mRNA and protein in T84 cells exposed to 45 degrees C for 10 min and allowed to recover for 6 h. L-NNA treatment for 1 h before HS inhibited the induction of HSP-70i mRNA and protein, with an IC(50) of 0.0471 +/- 0.0007 microM. Because the HS-induced increase in HSP-70i mRNA and protein is Ca(2+) dependent, we measured [Ca(2+)](i) after treating cells with L-NNA. L-NNA at 100 microM significantly decreased resting [Ca(2+)](i). Likewise, treatment with 1 microM GF-109203X or H-89 (inhibitors of PKC and PKA, respectively) for 30 min also significantly decreased [Ca(2+)](i) and inhibited HS-induced increase in HSP-70i. GF-109203X- or H-89-treated cells failed to respond to L-NNA by further decreasing [Ca(2+)](i) and HSP-70i. L-NNA effectively blocked heat shock factor-1 (HSF1) translocation from the cytosol to the nucleus, a process requiring PKC phosphorylation. These results suggest that L-NNA inhibits HSP-70i by reducing [Ca(2+)](i) and decreasing PKC and PKA activity, thereby blocking HSF1 translocation from the cytosol to the nucleus.