Faculty Bibliography

BACKGROUND:Management of patients with chronic limb-threatening ischemia (CLTI) and extensive foot necrosis presents a challenge for limb salvage. Our study evaluates preoperative risk factors that contributed to durability and efficacy of limb salvage after open transmetatarsal amputation (TMA) in patients with critical limb-threatening ischemia. METHODS:We abstracted data from patients who underwent open TMA at Los Angeles County-University of Southern California Medical Center and Keck Hospital of University of Southern California from 2009 to 2018. Multivariable logistic regression analysis, adjusting for preoperative risk factors, was used to examine predictors of major adverse limb events (MALE). The aim was to evaluate outcomes following open TMA with MALE as the primary outcome. Our hypotheses were that outcomes would be worse for patients with foot infections and renal failure. RESULTS:Forty-three open TMAs were done in 39 patients during the study period. The cohort had a mean age of 63 ± 11.6 years, 89% had a history of diabetes, 95% hypertension (HTN), 54% had end-stage renal disease (ESRD), and 26% were current smokers. MALE occurred in 39% of the cohort. Sex, race, indication, HTN, smoking status, and history of prior ipsilateral revascularization or minor amputations were not associated with MALE (P > 0.05). Multivariate logistic regression found ESRD to be an independent predictor of MALE (odds ratio 7.43, 95% confidence interval 1.12-49.17, P = 0.038) after adjusting for clinically significant covariates. CONCLUSIONS:Open TMA provides acceptable rates of limb salvage for complex patients with CLTI. ESRD is an independent risk factor for MALE following open TMA in these patients. Vigilant follow-up is essential for this morbid patient population given poorer outcomes after forefoot amputation.

BACKGROUND:Popliteal vascular injuries are common and frequently associated with limb loss. Although many studies have evaluated the treatment and outcomes of popliteal artery injuries (PAI), there is little available evidence regarding popliteal venous injuries (PVI). As such, substantial debate remains regarding the benefit of repair over ligation of PVI. The objectives of this study were to compare in-hospital outcomes of repair versus ligation of isolated PVI, as well as to determine nonvascular factors associated with worse outcomes. METHODS:Patients in the National Trauma Databank from 2007 to 2014 with at least one PVI were evaluated. First, patients with concomitant PVI and PAI were compared with patients with isolated PVI. Second, outcomes were compared between ligation and repair of isolated PVI. To limit the impact of concomitant injuries and focus on the impact of venous injury management, we defined isolated PVI as cases without concomitant PAI and with Abbreviated Injury Scale severity score of less than 3 for all body regions other than lower extremity. Patients dead on arrival and those with less than 18 years of age were excluded. The primary outcomes were in-hospital mortality, amputation, and in-hospital amputation-free survival (AFS). Secondary outcomes included lower extremity compartment syndrome, fasciotomy, acute kidney injury, pulmonary embolism, deep venous thrombosis, and inferior vena cava filter placement. RESULTS:Overall, 1819 patients (0.03%) had a PVI and after exclusion 1213 met the criteria for initial analysis. Of those, 308 had isolated PVI, and 905 had combined PVI and PAI. Patients with combined PVI and PAI had higher rates of amputation (15.2% vs 6.8%; P < .001), fasciotomy (64.5% vs 30.8%; P < .001), compartment syndrome (14.8% vs 8.8%; P = .006), and a lower AFS (82.9% vs 91.8%; P < .001) than patients with isolated PVI. There was no difference in in-hospital mortality, amputation, or in-hospital AFS between ligation and repair of isolated PVI. On multivariable logistic regression of isolated PVI, ligation was not independently associated with in-hospital AFS, amputation, or mortality. CONCLUSIONS:Ligation of isolated PVI was not an independent predictor of in-hospital mortality, lower extremity amputation, or in-hospital AFS. Ligation also did not result in higher rates of fasciotomy, acute kidney injury, or pulmonary embolism.

OBJECTIVE:A hospital-wide quality improvement process through a care delivery redesign (CDR) was initiated to improve patient care efficiency, clinical documentation, and length of stay (LOS). The impact of CDR was assessed through LOS, unplanned readmission rates, and hospital financial metrics. METHODS:The CDR team consisted of the Chief of Vascular Surgery, inpatient nurse practitioner, dedicated case manager, clinical documentation improvement specialist, and vascular surgery residents and faculty. The nurse practitioner facilitated patient care coordination, resident system-based education, and multidisciplinary collaboration. Tools created to track performance and to ensure sustainability included daily discussions of patient care barriers and solutions; standardized order sets; a mobile app for residents containing resident service expectations, disease-specific resources, and vascular surgery journal links; and a weekly inpatient tracker showing real-time patient care data. Outcome measures included LOS, case mix index, contribution margin, and unplanned readmissions. Each outcome was determined for all inpatient admissions the year before and the 12 months after CDR was initiated. Outcomes were compared between the two groups. RESULTS:Implementation of CDR resulted in a 23% decrease in LOS (P = .003), reducing the gap to the Centers for Medicare and Medicaid Services geometric mean LOS from 2.1 days to 0.5 day (P < .001). Clinical documentation resulted in an increase in case mix index of 10% (P = .011). The 30-day unplanned readmission rates did not change in the 12 months after CDR was initiated compared with the year before (P = .92). Financial data demonstrated decreased variable cost and increased revenue resulting in a $1.89 million increase in contribution margin. CONCLUSIONS:A CDR predicated on a dedicated service line advanced practitioner, clinical documentation education, weekly service tracker review, and real-time management of system-related barriers to patient care is described. Implementation of the CDR reduced hospital LOS with no change in unplanned readmissions and provided significant financial benefit to the hospital by increasing revenue and decreasing variable cost.

Left subclavian artery revascularization during endovascular repair of aortic dissection is often accomplished by left carotid-subclavian artery bypass or transposition. In situ fenestration of thoracic stent grafts provides an alternative method of revascularization without manipulation of the left carotid artery. We describe a case whereby in situ laser fenestration, combined with catheter-directed thrombectomy, was utilized to revascularize a thrombosed left subclavian artery following a frozen elephant trunk repair of type A aortic dissection. A 75-year-old male presented with pericardial tamponade and aortic insufficiency, secondary to type A aortic dissection. Patient underwent an emergent replacement of the aortic root, valve, arch, and ascending aorta in the frozen elephant trunk configuration. The innominate and left carotid arteries were revascularized with a bifurcated bypass graft from the ascending aortic graft. The left subclavian artery (LSCA) was covered with an antegrade deployment of a cTAG stent graft. During the immediate postoperative period, the patient was found to have a dissection of the left common carotid artery (LCCA) and pseudoaneurysm of the bypass graft anastomosis. The left carotid artery was replaced up to the proximal internal carotid. During rehabilitation, the patient developed left subclavian steal syndrome, with a CT angiography demonstrating thrombosis of the subclavian origin, and duplex ultrasound showing a reversal of the left vertebral flow. In order to revascularize the left subclavian artery without using the left carotid as the inflow, the in situ laser fenestration technique was planned. The vertebral artery origin was protected with a neuroclip through a supraclavicular incision. Through a brachial artery cutdown, a 9Fr flex sheath was positioned at the origin of the subclavian artery. A suction thrombectomy catheter was used to create a central channel in the thrombus. A 0.035″ 3.2 mm over-the-wire laser atherectomy catheter was used to create a fenestration through the cTAG stent graft. The subclavian branch stent was stented with an iCast balloon-expandable covered stent, excluding the mural thrombus. The patient recovered well with resolution of symptoms and was discharged home. Postoperative CT scan showed patent left subclavian branch stent and no endoleak across the fenestration of the aortic stent graft. Delayed laser in situ fenestration of a PTFE stent graft can be performed safely. The vertebral artery protection and catheter-directed thrombectomy are important adjuncts to reduce the risk of posterior stroke.

We report a case of a frozen elephant trunk arch repair, where the stent graft was unintentionally placed into the false lumen. Postoperative imaging demonstrated an enlarged false lumen with no thoracic aorta fenestrations that could be traversed to place another thoracic endovascular aortic repair endograft into the true lumen. An atraumatic radiofrequency wire (PowerWire, Baylis Medical, Montreal, Quebec, Canada) was used to create a new septal fenestration, enabling thoracic endovascular aortic repair endograft extension into the thoracic true lumen. This novel use of a radiofrequency wire can enable safe and controlled endovascular septal fenestration even in chronic dissections to redirect flow into the true lumen.

BACKGROUND:Surgical training is constantly adapting to better prepare trainees for an evolving landscape of surgical practice. Training in vascular surgery additionally underwent a paradigm shift with the introduction of the integrated training pathway now more than a decade ago. With this study, we sought to characterize the needs and goals of our current vascular surgery trainee population. METHODS:The Association of Program Directors in Vascular Surgery Issues Committee compiled a survey to assess demographics, current needs, and goals of trainees and to evaluate trainee distress using a validated seven-item Physician Well-Being Index. The survey was distributed electronically to all current vascular surgery trainees and recent graduates in the academic years 2016-2017 and 2017-2018, and responses were recorded anonymously. RESULTS:During the 2 years of the survey, the response rate was 30% (n = 367/1196). The respondents were 55% (n = 202) integrated vascular residents and 45% (n = 165) vascular surgery fellows. In each year of the survey, 60% (n = 102/170) and 58% (n = 86/148) of trainees expressed a desire to pursue academics in their careers, whereas 37% (n = 63/174) and 35% (n = 53/152) indicated their program had structured academic development time (2016-2017 and 2017-2018, respectively). Fifty-five percent (n = 96/174) and 52% (n = 79/152) stated that the overall impact of collaborative learners was positive. More than 60% of respondents in both years of the survey indicated experiencing one or more symptoms of distress on a weekly basis. The frequency of distress was associated with older age and with the presence of an advanced degree in both years of the survey. Sex, level of training, presence of collaborative learners, and having protected research time were not associated with frequency of distress in either year of the survey. CONCLUSIONS:These results highlight an opportunity for programs to further evaluate the needs of their trainees for academic development during vascular surgery training to better accommodate trainees' career goals. Further investigation to identify modifiable risk factors for distress among vascular surgery trainees is warranted.

OBJECTIVE:Treatment of type B aortic dissections with thoracic endovascular aortic repair (TEVAR) has been adopted in many centers with the goal of covering the proximal entry tear. Coverage of the left subclavian artery (LSCA) is commonly required to achieve a dissection-free proximal seal zone. A novel thoracic single side-branched (TSSB) endograft device offers a potential off-the-shelf option to achieve total endovascular incorporation of LSCA during zone 2 TEVAR. The aim of this study was to determine what percentage of patients with type B aortic dissection who require zone 2 TEVAR meet the anatomical requirements for this device. METHODS:All consecutive patients undergoing TEVAR for type B aortic dissections at a single institution from 2006 to 2016 were evaluated. Three-dimensional centerline reconstruction of preoperative computed tomography angiography was performed to identify the diameter of the aorta, distances between branch vessels, diameter of the target branch vessel, and location of the primary entry tear. Only patients who met criteria for zone 2 TEVAR were included in the analysis. The primary outcome was percentage of patients that meet all anatomical requirements for TSSB. Individual criteria were evaluated independently, and results were stratified by dissection chronicity. RESULTS:Eighty-seven patients who underwent TEVAR for Stanford type B aortic dissections were reviewed. Fifty-seven (66%) would have required zone 2 TEVAR. Indications for TEVAR were malperfusion (12), aneurysm (15), persistent pain (22), rupture (3), uncontrolled hypertension (5), and other (3). Mean follow-up was 19 months (range, 1-72 months). Only 16 of the 57 patients (28%) met all the requirements for anatomic suitability. The primary contributor was that only 49% of patients had sufficient length between arch branches to prevent coverage of a proximal branch. CONCLUSIONS:Although the new TSSB device can allow for a more proximal seal zone and eliminate the need for open aortic arch debranching, only 28% of patients with type B dissection who required zone 2 TEVAR met all the anatomic requirements for this device. Future devices will need to account for the short distance between the left carotid and LSCA to be more broadly applicable.

Atherosclerosis is a chronic disease characterized by the formation of calcified, arterial plaques. Microcalcifications (5 μm to 100 μm), mainly composed of hydroxyapatite (HA, Ca₅(PO₄)₃(OH)), develop in the fibrous caps of atherosclerotic plaques and can trigger plaque rupture due to the loss of compliance and elasticity. Ultimately, plaque rupture can cause arterial occlusion and embolization and result in ischemic events such as strokes and myocardial infarctions. Unfortunately, current imaging technologies used to detect calcifications are limited by low signal-to-noise ratio or use invasive procedures that pose risk of arterial dissection. To mitigate these drawbacks, in our study, we developed a novel, fluorescently-labeled peptide amphiphile micelle (PAM) that uses a 12 amino acid HA-binding peptide (HABP) [SVSVGMKPSPRP] to target and detect atherosclerotic calcification (HA PAM). Our results show HA PAMs can successfully target HA microcrystals with a strong binding affinity (K_D = 6.26 ± 1.2 μM) in vitro. In addition, HA PAMs detected HA mineralization (HA PAM vs. non-targeting micelle, p≤ 0.001; HA PAM vs. scrambled HABP PAM, p≤ 0.01) formed by calcifying mouse aortic vascular smooth muscle cells (MOVAS). Moreover, HA PAMs successfully detected calcifications in atherosclerotic mouse models as well as in patient-derived arteries. Our studies show that HA PAMs show promise as calcium-targeting nanoparticles for the detection of calcifications in atherosclerosis.

OBJECTIVE:Inferior vena cava (IVC) injuries are potentially lethal and require prompt intervention. Repair of complex IVC injuries may require the use of a prosthetic graft or a complicated panel or spiral vein graft reconstruction to avoid the need for ligation. Collateral venous drainage may be sufficient to allow acceptable results from IVC ligation; however, previous studies have suffered from low numbers and have differing results. The aims of this study were to assess the outcomes of isolated IVC injuries overall and to compare IVC ligation with repair. METHODS:Patients in the National Trauma Data Bank from 2007 to 2014 with an IVC injury were evaluated. Isolated IVC injury was defined as patients with nonvascular Abbreviated Injury Scale scores <4 and no other named vascular injury. The primary outcome was mortality; secondary outcomes were in-hospital amputation-free survival, major lower extremity amputation, lower extremity compartment syndrome, acute kidney injury (AKI), deep venous thrombosis (DVT), and pulmonary embolism (PE). RESULTS:Overall, 1075 (0.018%) patients had IVC injuries and 443 met inclusion criteria. On univariate analysis, in comparing IVC ligation and primary repair, ligation was not associated with mortality (23% vs 16%; P = .102) but was associated with blunt mechanism (22% vs 11%; P = .009), higher fasciotomy rate (11% vs 0%; P < .001), trend toward lower in-hospital amputation-free survival (76% vs 84.4%, P = .056), and higher rates of AKI (9% vs 4%; P = .060) and PE (3% vs 1%, P = .087). Similarly, major lower extremity amputation, compartment syndrome, and DVT were not different between groups. IVC ligation was not independently associated with mortality (adjusted odds ratio [AOR], 1.54; P = .197), in-hospital amputation-free survival (AOR, 0.61; P = .141), major amputation (AOR, Inf; P = .99), lower extremity compartment syndrome (AOR, 0.82; P = .827), or PE (AOR, 6.72; P = .052), but it was independently associated with fasciotomy (AOR, 31.4; P = .002), AKI (AOR, 2.7; P = .048), and DVT (AOR, 2.3; P = .021). CONCLUSIONS:IVC ligation was not independently associated with mortality or lower extremity amputation, but it was associated with AKI and need for fasciotomy.

Mortality after gunshot wounds to the thoracic aorta ranges from 92% to 100%. Survival is almost always in patients with injury from low-caliber, low-velocity bullets with hemorrhage contained by the wall of the aorta. Bullet embolization, even rarer with a reported incidence of 0.3% of vascular injuries, is most commonly found during autopsy. We report the successful treatment and survival of a patient who presented with a large-caliber gunshot wound to the aortic arch with contained rupture and bullet embolization from the aortic arch to the superficial femoral artery. The patient remained functionally independent and was discharged without complication.