Duplex ultrasound and clinical outcomes of medical management of pediatric lower extremity arterial thrombosis.

OBJECTIVES: Natural history and duplex ultrasound (DU) findings of pediatric lower extremity arterial thrombosis (PLEAT) are not well-defined. We describe acute and short-term DU findings of PLEAT to aid duplex interpretation and patient management. METHODS: From August 2018 to April 2021 children with suspected PLEAT were identified prospectively. All had DU studies and were divided into group 1 (with DU-confirmed PLEAT) and group 2 (without DU-confirmed PLEAT). Patient demographics and DU findings were compared. Those with PLEAT and follow-up DU studies were also evaluated for recanalization and post recanalization DU findings. RESULTS: We included 76 children (102 limbs) who had suspected PLEAT; 32 in group 1 and 44 group in 2. Fifty-seven percent had congenital heart disease, 26% a history prematurity (87%, 34% group 1; 11%, 14% group 2), with 14% of group 1 premature at PLEAT diagnosis and 68% aged less than 3 years-29 (94%) in group 1 and 23 (52%) in group 2. None had an arterial procedure to restore flow. Limb salvage was 100% with five group 1 mortalities unrelated to PLEAT. In group 1, 12 PLEATs were associated with an arterial line and 15 with cardiac catheterization. Occluded arteries included 7 external iliac, 20 common femoral, and 5 superficial femoral arteries (SFA). Peak systolic velocities (PSVs) distal to occluded segments in group 1 were lower than corresponding group 2 PSVs. SFA 18 ± 21 cm/s vs 84 ± 39 cm/s; popliteal artery (PA) 24 ± 18 cm/s vs 78 ± 38 cm/s; posterior tibial artery (PTA) 10 ± 8 cm/s versus 49 ± 27 cm/s (all P < .001). Twenty-one patients in group 1 had follow-up studies. Twelve (57%) were recanalized: 4 (19%) in less than 1 week and 10 (48%) by 6 months. Eighty-one percent of PLEATs were treated with anticoagulation (AC) and 57% recanalized. Fifty-nine percent of patients on AC recanalized, and 60% not on AC recanalized. Age, primary diagnosis, instrumentation type, and AC were not associated with failure to recanalize. After recanalization, PSVs in the CFA were not different than PSVs found in group 2 in the CFA (109 ± 50 cm/s vs 107 ± 57 cm/s; P = .88), but remained decreased in the SFA, PA, and PTA (SFA 68 ± 32 cm/s vs 83 ± 38 cm/s [P = .04]; PA 33 ± 13 cm/s vs 78 ± 37 [P = .0004]; and PTA 21 ± 8 cm/s vs 43 ± 20 cm/s [P = .0008]). CONCLUSIONS: PLEAT occurs in young children, results in low distal PSVs, and often does not recanalize, but does not lead to short-term limb loss or mortality or necessarily require AC for recanalization. Normalization of CFA PSVs indicates recanalization while PSVs in segments distal to the CFA do not seem to return to normal.

The Development and Usability of the AMPREDICT Decision Support Tool: A Mixed Methods Study.

OBJECTIVE: Amputation level decision making in patients with chronic limb threatening ischaemia is challenging. Currently, evidence relies on published average population risks rather than individual patient risks. The result is significant variation in the distribution of amputation levels across health systems, geographical regions, and time. Clinical decision support has been shown to enhance decision making, especially complex decision making. The goal of this study was to translate the previously validated AMPREDICT prediction models by developing and testing the usability of the AMPREDICT Decision Support Tool (DST), a novel, web based, clinical DST that calculates individual one year post-operative risk of death, re-amputation, and probability of achieving independent mobility by amputation level. METHODS: A mixed methods approach was used. Previously validated prediction models were translated into a web based DST with additional content and format developed by an expert panel. Tool usability was assessed using the Post-Study System Usability Questionnaire (PSSUQ; a 16 item scale with scores ranging from 1 to 7, where lower scores indicate greater usability) by 10 clinician end users from diverse specialties, sex, geography, and clinical experience. Think aloud, semi-structured, qualitative interviews evaluated the AMPREDICT DST's look and feel, user friendliness, readability, functionality, and potential implementation challenges. RESULTS: The PSSUQ overall and subscale scores were favourable, with a mean overall total score of 1.57 (standard deviation [SD] 0.69) and a range from 1.00 to 3.21. The potential clinical utility of the DST included (1) assistance in counselling patients on amputation level decisions, (2) setting outcome expectations, and (3) use as a tool in the academic environment to facilitate understanding of factors that contribute to various outcome risks. CONCLUSION: After extensive iterative development and testing, the AMPREDICT DST was found to demonstrate strong usability characteristics and clinical relevance. Further evaluation will benefit from integration into an electronic health record with assessment of its impact on physician and patient shared amputation level decision making.

Peak systolic velocity and color aliasing are important in the development of duplex ultrasound criteria for external carotid artery stenosis.

OBJECTIVE: The external carotid artery (ECA) serves as a major collateral pathway for ophthalmic and cerebral artery blood supply. It is routinely examined as part of carotid duplex ultrasound, but criteria for determining ECA stenosis are poorly characterized and typically extrapolated from internal carotid artery data. This is despite the fact that the ECA is smaller in diameter, with a higher resistance and lower volume flow pattern. We hypothesized that using the cutoff of a peak systolic velocity (PSV) ≥125 cm/s, extrapolated from internal carotid artery data, will overestimate the prevalence of ≥50% ECA stenosis and aimed to determine a more appropriate criterion. METHODS: From December 2016 to July 2017, consecutive carotid duplex ultrasound studies performed in our university hospital Intersocietal Accreditation Commission-accredited vascular laboratory were prospectively identified and categorized with respect to prevalence and distribution of ECA PSVs and color aliasing, an indication of turbulent flow or flow acceleration. Presence of color aliasing was determined by two individual reviewers and agreement assessed by Cohen κ coefficient. ECA stenosis was calculated by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method in patients with computed tomography angiography (CTA) performed within 3 months of carotid duplex ultrasound without an intervening intervention. Receiver operating characteristic analysis was performed to identify best criteria for determining ≥50% ECA stenosis. RESULTS: There were 1324 ECAs from 662 patients analyzed; 174 patients had a total of 252 ECAs with PSV ≥125 cm/s (19% of the total sample). Of those ECAs with PSVs ≥125 cm/s, 30.5% were between 125 and 149 cm/s, 22.2% were between 150 and 174 cm/s, 13.1% were between 175 and 199 cm/s, and 34.1% were ≥200 cm/s. There were 341 ECAs that were analyzed for the presence of color aliasing. In 86 ECAs with PSV ≥200 cm/s, 58.1% had color aliasing, whereas in 255 ECAs with PSV <200 cm/s, only 19.2% had color aliasing (P = .0001). There were 325 CTA studies reviewed and assessed for the presence of a ≥50% ECA stenosis as determined by CTA. Overall, the combination of an ECA PSV ≥200 cm/s with the presence of color aliasing provided the highest combination of sensitivity (90%), specificity (96%), positive predictive value (83%), and negative predictive value (98%) and the greatest area under the curve of 0.971 for determining the presence of a ≥50% ECA stenosis based on CTA. CONCLUSIONS: A PSV ≥125 cm/s alone probably overestimates the prevalence of ≥50% ECA stenosis. A PSV ≥200 cm/s combined with color aliasing is highly predictive of >50% ECA stenosis based on correlation with CTA.

Experienced operators achieve superior patency and wound complication rates with endoscopic great saphenous vein harvest compared with open harvest in lower extremity bypasses.

OBJECTIVE: Prior studies have suggested improved wound complication rates but decreased primary patency in lower extremity bypasses performed with endoscopic vein harvest (EVH) vs open vein harvest (OVH). We hypothesize that the inferior patency reflects the initial learning curve for EVH and that improved patency can be achieved with experience. METHODS: This was a single-institution review of 113 patients with critical limb ischemia who underwent infrainguinal bypass with a continuous segment of great saphenous vein harvested endoscopically (n = 49) or through a single open incision (n = 64) from 2012 to 2017. EVH was performed by surgeons with >5 years' experience with this technique. Operative outcomes, patency, complications, and readmission rates were compared between the harvest methods. EVH data were also compared with our prior reported series of our initial experience with this technique to determine the effects of experience on outcomes. RESULTS: There were no significant differences in patient demographics, medications, operative indications, or inflow/outflow vessels between the two groups. Mean operative time was 322 minutes and median hospital length of stay was 6 days for OVH, and was 340 minutes and 5 days for EVH, which was not significant. Harvest-related wound complications were more frequent with OVH (28% vs 2%, P < .001). Primary patency at 1 and 3 years was 65% and 58% for OVH, and 79% and 71% for EVH, respectively (P = .18), assisted primary patency was 77% and 74% for OVH and 94% and 89% for EVH, respectively (P = .05), and secondary patency was 82% and 79% for OVH and 95% and 95% for EVH, respectively (P = .03). The 30-day readmission rates were similar between OVH (20%) and EVH (12%, P = .26), but 90-day readmissions were more frequent in the OVH group (34% vs 14%, P = .018). Compared with our earlier series of EVH, the current cohort had significantly improved 3-year primary (71% vs 42%, P = .012), primary assisted patency (89 vs 66%, P = .034), and secondary patency (95% vs 66%, P = .003). CONCLUSIONS: With experience, lower extremity bypass using EVH can result in improved patency compared with OVH and initial EVH use, while also resulting in fewer wound complications and readmissions, with comparable operative times and hospital length of stay. This technique should be more widely adopted by vascular surgeons as a primary method of vein harvest.

Tibial artery duplex ultrasound-derived peak systolic velocities may be an objective performance measure after above-knee endovascular therapy for arterial stenosis.

OBJECTIVE: The ankle-brachial index (ABI) is a well-established measure of distal perfusion in lower extremity ischemia; however, the ABI is of limited value in patients with noncompressible lower extremity arteries. We sought to demonstrate whether duplex ultrasound-determined tibial artery velocities can be used as an alternative to ABI as an objective performance measure after endovascular treatment of above-knee arterial stenosis. METHODS: Thirty-six patients undergoing above-knee endovascular intervention had preprocedure and postprocedure duplex ultrasound examination within 6 months of intervention. Preprocedure vs postprocedure changes in tibial artery mean peak systolic velocity (PSV; mean of proximal, mid, and distal velocities) were compared with changes in ABI and a reference (control) cohort of 68 patients without peripheral vascular disease. RESULTS: Thirty-six patients (41 limbs) had an above-knee endovascular intervention and had preprocedure and postprocedure duplex ultrasound examinations of the ipsilateral extremity including the tibial arteries. Before the procedure, mean tibial artery PSVs in the 36 patients undergoing intervention were outside (below) the 95% confidence intervals for the control patients. In comparing preprocedure and postprocedure PSVs, the mean anterior tibial (P < .01), mean peroneal (P < .01), and mean posterior tibial (P < .01) PSVs all increased and correlated with an increase in ABI (P < .01). After endovascular intervention, duplex ultrasound-derived mean PSVs fell within or near established reference ranges for patients without peripheral arterial disease. Mean tibial artery PSV increases were similar in patients with and without noncompressible vessels. CONCLUSIONS: Tibial artery PSVs increase, correlate with an increase in ABI, and fall within or near confidence intervals for normal controls after above-knee endovascular interventions. After endovascular intervention, tibial artery PSVs can supplement ABI as an objective performance measure in patients with and in particular without compressible tibial arteries.

Interhospital vascular surgery transfers to a tertiary care hospital.

OBJECTIVE: Interhospital transfers (IHTs) to tertiary care centers are linked to lower operative mortality in vascular surgery patients. However, IHT incurs great health care costs, and some transfers may be unnecessary or futile. In this study, we characterize the patterns of IHT at a tertiary care center to examine appropriateness of transfer for vascular surgery care. METHODS: A retrospective review was performed of all IHT requests made to our institution from July 2014 to October 2015. Interhospital physician communication and reasons for not accepting transfers were reviewed. Diagnosis, intervention, referring hospital size, and mortality were examined. Follow-up for all patients was reviewed. RESULTS: We reviewed 235 IHT requests for vascular surgical care involving 210 patients during 15 months; 33% of requested transfers did not occur, most commonly after communication with the physician resulting in reassurance (35%), clinic referral (30%), or further local workup obviating need for transfer (11%); 67% of requests were accepted. Accepted transfers generally carried life- or limb-threatening diagnoses (70%). Next most common transfer reasons were infection or nonhealing wounds (7%) and nonurgent postoperative complications (7%). Of accepted transfers, 72% resulted in operative or endovascular intervention; 20% were performed <8 hours of arrival, 12% <24 hours of arrival, and 68% during hospital admission (average of 3 days); 28% of accepted patients received no intervention. Small hospitals (<100 beds) were more likely than large hospitals (>300 beds) to transfer patients not requiring intervention (47% vs 18%; P = .005) and for infection or nonhealing wounds (30% vs 10%; P = .013). Based on referring hospital size, there was no difference in IHTs requiring emergent, urgent, or nonurgent operations. There was also no difference in transport time, time from consultation to arrival, or death of patients according to hospital size. Overall patient mortality was 12%. CONCLUSIONS: Expectedly, most vascular surgery IHTs are for life- or limb-threatening diagnoses, and most of these patients receive an operation. Transfer efficiency and surgical case urgency are similar across hospital sizes. Nonoperative IHTs are sent more often by small hospitals and may represent a resource disparity that would benefit from regionalizing nonurgent vascular care.

Intraluminal thrombus is associated with early rupture of abdominal aortic aneurysm.

BACKGROUND: The implications of intraluminal thrombus (ILT) in abdominal aortic aneurysm (AAA) are currently unclear. Previous studies have demonstrated that ILT provides a biomechanical advantage by decreasing wall stress, whereas other studies have associated ILT with aortic wall weakening. It is further unclear why some aneurysms rupture at much smaller diameters than others. In this study, we sought to explore the association between ILT and risk of AAA rupture, particularly in small aneurysms. METHODS: Patients were retrospectively identified and categorized by maximum aneurysm diameter and rupture status: small (<60 mm) or large (≥60 mm) and ruptured (rAAA) or nonruptured (non-rAAA). Three-dimensional AAA anatomy was digitally reconstructed from computed tomography angiograms for each patient. Finite element analysis was then performed to calculate peak wall stress (PWS) and mean wall stress (MWS) using the patient's systolic blood pressure. AAA geometric properties, including normalized ILT thickness (mean ILT thickness/maximum diameter) and % volume (100 × ILT volume/total AAA volume), were also quantified. RESULTS: Patients with small rAAAs had PWS of 123 ± 51 kPa, which was significantly lower than that of patients with large rAAAs (242 ± 130 kPa; P = .04), small non-rAAAs (204 ± 60 kPa; P < .01), and large non-rAAAs (270 ± 106 kPa; P < .01). Patients with small rAAAs also had lower MWS (44 ± 14 kPa vs 82 ± 20 kPa; P < .02) compared with patients with large non-rAAAs. ILT % volume and normalized ILT thickness were greater in small rAAAs (68% ± 11%; 0.16 ± 0.04 mm) compared with small non-rAAAs (53% ± 16% [P = .02]; 0.11 ± 0.04 mm [P < .01]) and large non-rAAAs (57% ± 12% [P = .02]; 0.12 ± 0.03 mm [P < .01]). Increased ILT % volume was associated with both decreased MWS and decreased PWS. CONCLUSIONS: This study found that although increased ILT is associated with lower MWS and PWS, it is also associated with aneurysm rupture at smaller diameters and lower stress. Therefore, the protective biomechanical advantage that ILT provides by lowering wall stress seems to be outweighed by weakening of the AAA wall, particularly in patients with small rAAAs. This study suggests that high ILT burden may be a surrogate marker of decreased aortic wall strength and a characteristic of high-risk small aneurysms.

Ambulation and functional outcome after major lower extremity amputation.

OBJECTIVE: Major lower extremity amputations (MLEAs) remain a significant source of disability. It is unknown whether postamputation functional outcomes and outcome predictability have changed with a population of increasingly aging and obese patients. Accordingly, we sought to evaluate contemporary trends. METHODS: A retrospective chart review was performed to identify patients undergoing MLEA using Current Procedural Terminology codes in a university hospital. Demographics, comorbidities, perioperative variables, and outcomes were obtained. Descriptive statistics, t-tests, and χ2 and multivariate logistic regression modeling were used where appropriate. Survival analyses were performed with the Kaplan-Meier method. RESULTS: From October 2005 to November 2016, 206 patients (147 male; mean age, 63 ± 13.5 years) underwent 256 MLEAs (90.9% below-knee amputations, 1.3% through-knee amputations, and 7.8% above-knee amputations [AKAs]) related to acute and critical limb ischemia, infection, or other causes. Mean follow-up was 178.7 ± 266.9 days. Conversion from below-knee amputation to AKA was 3.5%. Estimated 1-year survival was 83%, and it was 15% lower in nonambulatory patients (75% vs 90%; P = .04). Overall 1-year postamputation ambulatory rate was 46.1%. Nonambulatory patients had a higher body mass index (30.9 ± 8.0 vs 25.6 ± 5.4; P < .001), lower preoperative hematocrit (31.0% ± 7.4% vs 33.3% ± 8.1%; P < .05), higher modified frailty index (mFI; 8.4 ± 1.0 vs 5.4 ± 1.2; P < .0001), higher chronic alcohol use (9% vs 1%; P = .01), dependent preoperative functional status (29% vs 2.1%; P < .01), and lack of family support (66.3% vs 17.9%; P < .01); they were less likely to be married (83.2% vs 35.8%; P < .01) and more likely to have an AKA (20% vs 52.6%; P = .004). There were no patients with dementia, on dialysis, or with bilateral MLEAs who were ambulatory after amputation. Factors predictive of nonambulatory status after MLEA with multivariate logistic regression analysis included increased body mass index (odds ratio [OR], 0.88; 95% confidence interval [CI], 0.81-0.98; P = .017) and an increased mFI (OR, 0.23; 95% CI, 0.16-0.34; P < .0001); a higher hemoglobin level was protective (OR, 1.3; 95% CI, 1.03-1.62; P = .019). CONCLUSIONS: Patients should be counseled that <50% of patients receiving MLEAs are ambulatory after amputation. Educating patients about the deleterious effects of obesity on ambulatory status after MLEA may motivate patients to improve their level of fitness to achieve successful ambulation. Patients with an elevated mFI, patients with dementia, and those on dialysis should be considered for AKAs.

Causes and outcomes of finger ischemia in hospitalized patients in the intensive care unit.

OBJECTIVE: Vascular surgeons may be consulted to evaluate hospitalized patients with finger ischemia. We sought to characterize causes and outcomes of finger ischemia in intensive care unit (ICU) patients. METHODS: All ICU patients who underwent evaluation for finger ischemia from 2008 to 2015 were reviewed. All were evaluated with finger photoplethysmography. The patients' demographics, comorbidities, ICU care (ventilator status, arterial lines, use of vasoactive medications), finger amputations, and survival were also recorded. ICU patients were compared with concurrently evaluated non-ICU inpatients with finger ischemia. RESULTS: There were 98 ICU patients (55 male, 43 female) identified. The mean age was 57.1 ± 16.8 years. Of these patients, 42 (43%) were in the surgical ICU and 56 (57%) in the medical ICU. Seventy (72%) had abnormal findings on finger photoplethysmography, 40 (69%) unilateral and 30 (31%) bilateral. Thirty-six (37%) had ischemia associated with an arterial line. Twelve (13%) had concomitant toe ischemia. Eighty (82%) were receiving vasoactive medications at the time of diagnosis, with the most frequent being phenylephrine (55%), norepinephrine (47%), ephedrine (31%), epinephrine (26%), and vasopressin (24%). Treatment was with anticoagulation in 88 (90%; therapeutic, 48%; prophylactic, 42%) and antiplatelet agents in 59 (60%; aspirin, 51%; clopidogrel, 15%). Other frequently associated conditions included mechanical ventilation at time of diagnosis (37%), diabetes (34%), peripheral arterial disease (32%), dialysis dependence (31%), cancer (24%), and sepsis (20%). Only five patients (5%) ultimately required finger amputation. The 30-day, 1-year, and 3-year survival was 84%, 69%, and 59%. By Cox proportional hazards modeling, cancer (hazard ratio, 2.4; 95% confidence interval, 1.1-5.6; P = .035) was an independent predictor of mortality. There were 50 concurrent non-ICU patients with finger ischemia. Non-ICU patients were more likely to have connective tissue disorders (26% vs 13%; P = .05) and hyperlipidemia (42% vs 24%; P = .03) and to undergo finger amputations (16% vs 5%; P = .03). CONCLUSIONS: Finger ischemia in the ICU is frequently associated with the presence of arterial lines and the use of vasopressor medications, of which phenylephrine and norepinephrine are most frequent. Anticoagulation or antiplatelet therapy is appropriate treatment. Whereas progression to amputation is rare, patients with finger ischemia in the ICU have a high rate of mortality, particularly in the presence of cancer. Non-ICU patients hospitalized with finger ischemia more frequently require finger amputations, probably because of more frequent connective tissue disorders.

Venous Conduits Have Superior Patency Compared with Prosthetic Grafts for Femorofemoral Bypass.

BACKGROUND: The objective of the study was to compare the outcomes of externally supported polytetrafluoroethylene (PTFE) grafts and femoral vein as conduits for femorofemoral crossover grafts. METHODS: This is a retrospective review of consecutive femorofemoral crossover grafts at our institution between January 2005 and March 2016. Patient demographics, indications, complication rates, patency rates, and survival rates were compared between femorofemoral grafts created with either PTFE or femoral vein conduits, autogenous or cryopreserved. RESULTS: One hundred nineteen femorofemoral crossover bypasses (89 PTFE, 30 vein [18 autogenous and 12 cryopreserved femoral veins]) were performed. Most patients underwent isolated femorofemoral bypass alone (76% isolated femorofemoral bypass versus 24% axillobifemoral bypass). A greater proportion of patients who received vein grafts were female (PTFE 37% vs. vein 60%, P = 0.028) and had prior bypasses (PTFE 33% vs. vein 73%, P < 0.001). PTFE bypasses were performed primarily for chronic limb ischemia (61.8%), while most venous bypasses were for infections (80%, P < 0.001). Femoral vein conduits were used in cases of infected aortic or extra-anatomical grafts (N = 20) or groin infection (N = 5). The 30-day complication rate was 38.7% and was not different between groups (36% for PTFE, 44.4% for autologous vein grafts and 50% for cryovein, P = 0.33) with wound complications being most frequent (18% PTFE, 27.8% autologous vein, 16.7% cryovein, P = 0.25). Patients receiving vein grafts were more likely to receive blood transfusion (34.8% PTFE vs. 70% vein, P = 0.001). Overall, median follow-up was 9.8 months (range 0-107). Primary patency rates at 1, 2, and 3 years were 83.7 %, 73.7% and 69.8%, respectively, for PTFE bypasses, and 100% for all time points for venous grafts, respectively (log rank, P = 0.03). Primary-assisted and secondary patency rates were not significantly different between the 2 groups (log rank, P = 0.16). Survival rates at 1, 2, and 3 years were 82%, 76.4% and 69.7%, respectively, for patients with PTFE grafts versus 76.7%, 73.3%, and 55%, respectively, for patients with vein grafts, respectively (log rank, P = 0.17). CONCLUSIONS: While the indications for procedure differed in this series, femoral veins in femorofemoral bypasses have overall superior primary patency and similar complication rates compared with PTFE grafts. Based on this series, femoral vein, either autologous or cryopreserved, appears to be a suitable conduit for femorofemoral bypasses, and in some cases, it may be the preferred conduit.

Quality-of-life assessment as an outcomes measure in critical limb ischemia.

Critical limb ischemia (CLI) is a diagnosis plagued by significant comorbidity and high mortality rates. Overall survival remains poor in this population regardless of the procedure-related success as demonstrated by freedom from amputation, intervention, and patency. The literature has traditionally focused on physician-centered and lesion-centered outcomes with regards to limb salvage procedures, but there remains a relative paucity of studies of CLI patients describing patient-centered outcomes such as quality of life (QoL), independent living, and ambulation status. Review of the available literature indicates patients do not always experience significant gains in their QoL after limb salvage interventions, despite reasonable graft patency, amputation-free survival, and limb salvage rates. Further research is required using QoL tools in a measurable and clinically relevant fashion to guide optimal quality care that maximizes patient-centered outcomes.

Predictive value of neutrophil-to-lymphocyte ratio in diabetic wound healing.

OBJECTIVE: The neutrophil-to-lymphocyte ratio (NLR) has been used as a surrogate marker of systemic inflammation. We sought to investigate the association between NLR and wound healing in diabetic wounds. METHODS: The outcomes of 120 diabetic foot ulcers in 101 patients referred from August 2011 to December 2014 were examined retrospectively. Demographic, patient-specific, and wound-specific variables as well as NLR at baseline visit were assessed. Outcomes were classified as ulcer healing, minor amputation, major amputation, and chronic ulcer. RESULTS: The subjects' mean age was 59.4 ± 13.0 years, and 67 (66%) were male. Final outcome was complete healing in 24 ulcers (20%), minor amputation in 58 (48%) and major amputation in 16 (13%), and 22 chronic ulcers (18%) at the last follow-up (median follow-up time, 6.8 months). In multivariate analysis, higher NLR (odds ratio, 13.61; P = .01) was associated with higher odds of nonhealing. CONCLUSIONS: NLR can predict odds of complete healing in diabetic foot ulcers independent of wound infection and other factors.

Effect of systemic insulin treatment on diabetic wound healing.

This study investigates if different diabetic treatment regimens affect diabetic foot ulcer healing. From January 2013 to December 2014, 107 diabetic foot ulcers in 85 patients were followed until wound healing, amputation or development of a nonhealing ulcer at the last follow-up visit. Demographic data, diabetic treatment regimens, presence of peripheral vascular disease, wound characteristics, and outcome were collected. Nonhealing wound was defined as major or minor amputation or those who did not have complete healing until the last observation. Median age was 60.0 years (range: 31.1-90.1 years) and 58 cases (68.2%) were males. Twenty-four cases reached a complete healing (healing rate: 22.4%). The median follow-up period in subjects with classified as having chronic wounds was 6.0 months (range: 0.7-21.8 months). Insulin treatment was a part of diabetes management in 52 (61.2%) cases. Insulin therapy significantly increased the wound healing rate (30.3% [20/66 ulcers] vs. 9.8% [4/41 ulcers]) (p = 0.013). In multivariate random-effect logistic regression model, adjusting for age, gender, smoking status, type of diabetes, hypertension, chronic kidney disease, peripheral arterial disease, oral hypoglycemic use, wound infection, involved side, presence of Charcot's deformity, gangrene, osteomyelitis on x-ray, and serum hemoglobin A1C levels, insulin treatment was associated with a higher chance of complete healing (beta ± SE: 15.2 ± 6.1, p = 0.013). Systemic insulin treatment can improve wound healing in diabetic ulcers after adjusting for multiple confounding covariates.

Normal Lower Extremity Duplex Findings in Patients with Left Ventricular Assist Devices: A Basis for Vascular Laboratory Interpretation.

BACKGROUND: Left ventricular assist devices (LVADs) have been shown to cause changes in carotid artery duplex-derived flow velocity waveforms; however, possible effects on lower extremity arterial duplex (LEAD) findings have not been characterized. We sought to characterize LEAD findings in patients with LVADs to establish a basis for vascular laboratory interpretation of LEAD in patients with LVADs. METHODS: Retrospective single institution review of all patients with LEAD performed after LVAD implantation from 2003 to 2014. Peak systolic velocity (PSVs) of common femoral (CFA), superficial femoral (SFA), popliteal, and posterior tibial arteries (PTA) in asymptomatic extremities in patients with LVADs were compared to a control group of patients at our institution without LVADs who underwent LEAD for nonischemic indications. Arterial brachial index (ABIs) and CFA waveform acceleration times (ATs) and end diastolic velocity (EDV) were also measured. RESULTS: There were 248 LVAD patients, 29 had LEAD of at least 1 lower extremity (34 extremities, 22 asymptomatic, and 12 symptomatic) during the study period and 136 control limbs. Mean PSVs (cm/s) in the control CFA, mid SFA, popliteal, and PTA were 137 ± 4.8, 104.2 ± 4.5, 65.2 ± 2.8, and 64.6 ±3.2. Mean PSVs were significantly decreased in the LVAD patients: 49.5 ± 4.9, 40.6 ± 3.7, 27.2 ± 2.2, and 25.5 ± 2.3, P < 0.001 for each comparison. Average ABI for control limbs was 0.91 ± 0.05 compared to 1.17 ± 0.35 in LVAD extremities (P < 0.001). Mean CFA AT was 97 ms in the controls and 207 ms in LVAD patients, P < 0.001. Mean CFA EDV was 14.7 cm/s in the controls and 18.6 cm/s in the LVAD patients, P = 0.011. CONCLUSIONS: This is the first study characterizing LEAD in lower extremity arteries in LVAD patients. PSV is significantly decreased throughout lower extremity vessels, and common femoral artery acceleration time increased. Results can serve as a basis for identifying normal LEAD findings in LVAD patients.

Exercise versus vasodilator stress limb perfusion imaging for the assessment of peripheral artery disease.

PURPOSE: Our aim was to determine whether pharmacologic vasodilation is an alternative to exercise stress during limb perfusion imaging for peripheral artery disease (PAD). METHODS: Quantitative contrast-enhanced ultrasound (CEU) perfusion imaging of the bilateral anterior thigh and calf was performed in nine control subjects and nine patients with moderate to severe PAD at rest and during vasodilator stress with dipyridamole. For those who were able, CEU of the calf was then performed during modest plantar flexion exercise (20 watts). CEU time-intensity data were analyzed to quantify microvascular blood flow (MBF) and its parametric components of microvascular blood volume and flux rate. RESULTS: Thigh and calf skeletal muscle MBF at rest was similar between control and PAD patients. During dipyridamole, MBF increased minimally (

Statin use in patients with peripheral arterial disease.

BACKGROUND: Statins are recommended for use in patients with peripheral arterial disease (PAD) to reduce cardiovascular events and mortality. However, much of the data regarding benefits of statins stem from the cardiovascular literature. Here, we review the literature regarding statin use specifically in patients with PAD regarding its effects on cardiovascular events and mortality, limb-related outcomes, statin use after endovascular interventions, statin dosing, and concerns about statins. METHODS: We performed a literature review using PubMed for literature after the year 2000. Search terms included "statins," "peripheral arterial disease," "peripheral vascular disease," "lipid-lowering medication," and "cardiovascular disease." RESULTS: There is good evidence of statins lowering cardiovascular events and cardiovascular-related mortality in patients with PAD. Though revascularization rates were reduced with statins, amputation rates and amputation-free survival did not improve. Small randomized controlled trials show that patients taking statins can slightly improve pain-free walking distance or pain-free walking time, although the extent of the effect on quality of life is unclear. Statin use for patients undergoing endovascular interventions is recommended because of the reduction of postoperative cardiovascular events. Not enough data exist to support local effects of systemic statin therapy, such as prevention of restenosis. For statin dosing, there is little increased benefit to intense therapy compared with the adverse effects, whereas moderate-dose therapy has significant benefits with very few adverse effects. Adverse effects of moderate-dose statin therapy are rare and mild and are greatly outweighed by the cardiovascular benefits. CONCLUSIONS: There is strong evidence to support use of statins in patients with PAD to reduce cardiovascular events and mortality. Use in patients undergoing open and endovascular interventions is also recommended. Statin use may reduce the need for revascularization, but reductions in amputation have not been shown. Moderate-dose statin therapy is safe, and the minor risks are greatly outweighed by benefits.

Outcomes of unilateral graft limb excision for infected aortobifemoral graft limb.

OBJECTIVE: Aortobifemoral graft (ABFG) infections presenting with apparent single-limb involvement can be managed with unilateral graft limb excision or complete graft removal. This study aimed to identify outcomes of unilateral graft limb excision for infected ABFGs and factors predictive of subsequent contralateral or main body graft limb infection. METHODS: A retrospective review of patients treated with unilateral graft limb excision for infection of an isolated limb of an ABFG from 2001 to July 2014 was performed. Endovascular and aortic tube graft infections were excluded. Outcomes were freedom from contralateral graft limb excision, overall survival, and factors predicting subsequent contralateral limb or main body infection. RESULTS: Fifteen patients underwent unilateral graft limb excision and revascularization for treatment of an infected ABFG isolated to one graft limb. Indications for the original ABFG were aortoiliac occlusive disease in 11 patients and aortoiliac aneurysm in 4 patients. All patients presented with clinical evidence consistent with unilateral graft limb infection and clinical findings confirmed radiographically. Unilateral graft explantation was performed for isolated infrainguinal graft limb infection with no retroperitoneal infection on exploration or if patients were too ill to tolerate total graft explantation despite infection in the retroperitoneum. Seven patients, all of whom underwent initial operation for aortoiliac occlusive disease, developed contralateral limb infection at a median follow-up of 23.2 months after unilateral excision. The remaining eight patients remained free of contralateral graft limb infection at median follow-up of 38.8 months. Patient demographics were similar between the two groups. Factors predictive of contralateral graft limb infection included an ABFG placed for aortoiliac occlusive disease (P = .03) and culture evidence of infection above the inguinal ligament (P = .07; positive predictive value of 71%). Median duration of targeted antibiotic therapy was 42 days, and neither duration of antibiotics nor cultured microorganism predicted recurrent graft infection. Overall mortality was 40% and was similar between patients who developed contralateral or main body graft infection and those who did not. There was no limb loss, and overall median follow-up was 44.7 months. CONCLUSIONS: Isolated unilateral infection of an ABFG limb can be managed with single graft limb excision, provided the infection is isolated to the infrainguinal graft segment. Factors predicting subsequent contralateral or main body graft infection include ABFGs originally placed for aortoiliac occlusive disease and culture-positive graft infection above the inguinal ligament.

Quantification of residual limb skeletal muscle perfusion with contrast-enhanced ultrasound during application of a focal junctional tourniquet.

OBJECTIVE: Focal junctional tourniquets (JTs) have been developed to control hemorrhage from proximal limb injuries. These devices may permit greater collateral perfusion than circumferential tourniquets. We hypothesized that JTs eliminate large-vessel pulse pressure yet allow a small amount of residual limb perfusion that could be useful for maintaining tissue viability. METHODS: Ten healthy control subjects were studied. Transthoracic echocardiography, Doppler ultrasound of the femoral artery (FA) and posterior tibial artery, and contrast-enhanced ultrasound (CEU) perfusion imaging of the anterior thigh extensor and calf plantar flexor muscles were performed at baseline and during application of a JT over the common FA. Intramuscular arterial pulsatility index was also measured from CEU intensity variation during the cardiac cycle. RESULTS: FA flow was eliminated by JTs in all subjects; posterior tibial flow was eliminated in all but one. Perfusion measured in the thigh and calf muscles was similar at baseline (0.33 ± 0.29 vs 0.29 ± 0.22 mL/min/g). Application of the JT resulted in a reduction of perfusion (P < .05) that was similar for the thigh and calf (0.08 ± 0.07 and 0.10 ± 0.03 mL/min/g). On CEU, microvascular flux rate was reduced by ≈55%, and functional microvascular blood volume was reduced by ≈35%. Arterial pulsatility index was reduced by ≈90% in the calf. JT inflation did not alter left ventricle dimensions, fractional shortening, cardiac output, or arterial elastance as a measure of total systolic load. CONCLUSIONS: Application of a JT eliminates conduit arterial pulse and markedly reduces intramuscular pulse pressure, but thigh and calf skeletal muscle perfusion is maintained at 25% to 35% of basal levels. These data suggest that JTs that are used to control limb hemorrhage allow residual tissue perfusion even when pulse pressure is absent.

Arterial duplex for diagnosis of peripheral arterial emboli.

BACKGROUND: Whether duplex ultrasound (DUS) imaging alone can be used to successfully plan revascularization for peripheral arterial embolism (PAE) is unknown. This study evaluated the utility of DUS imaging alone for the diagnosis and treatment of PAE. METHODS: Patients with cardiogenic PAE to the lower or upper extremities during a 20-year period were retrospectively evaluated. Patients with visceral or cerebral PAE were excluded. Diagnosis by DUS imaging alone was compared with contrast angiography (CA) or computed tomography angiography (CTA). Patient demographics, use of intraoperative CA, need for reintervention, length of revascularization procedure, and rate of fasciotomy and amputation were compared. Mean peak systolic velocity (PSV; cm/s) measured at the proximal, middle, and distal segment of each artery from the common femoral to the distal tibial arteries was also compared with surgical outcomes. RESULTS: We identified 203 extremities in 182 patients with PAE. Preoperative imaging was obtained in 89%, including DUS imaging alone (44%), CA (37%), and CTA (7%). DUS imaging was used more frequently than CA or CTA in women, older patients, patients with congestive heart failure, upper extremity PAE, and patients on antiplatelet agents preoperatively. Use of intraoperative CA, need for reintervention, rate of fasciotomy and limb loss, and hospital length of stay were similar between the two groups. No upper extremities required amputation. Patients with lower extremity emboli who underwent fasciotomy had lower mean PSVs than those free from fasciotomy at the popliteal (4 ± 6 cm/s vs 31 ± 62 cm/s; P = .03), anterior tibial (1 ± 3 cm/s vs 10 ± 16 cm/s; P = .004), and posterior tibial (2 ± 3 cm/s vs 9 ± 15 cm/s; P = .03) arteries. The 30-day mortality for the series was 25% with a median follow-up of 7.4 months. The only predictor of 30-day mortality on multivariate analysis was tobacco use (odds ratio, 3.1; 95% confidence interval, 1.4-7.0). CONCLUSIONS: Surgical outcomes and survival for patients evaluated by preoperative DUS imaging alone for PAE are equivalent to patients evaluated with CA or CTA. PSVs in the tibiopopliteal arteries may predict the need for fasciotomy. Preoperative DUS imaging alone is sufficient for operative planning in patients with symptoms suggestive of PAE.

Characterization of tibial velocities by duplex ultrasound in severe peripheral arterial disease and controls.

BACKGROUND: The relationship between tibiopopliteal velocities and peripheral arterial disease (PAD) severity is not well understood. We sought to characterize tibiopopliteal velocities in severe PAD and non-PAD control patients. METHODS: Patients with an arterial duplex ultrasound (DUS) examination with PAD evaluated during a 5-year period were retrospectively compared with non-PAD controls. Control DUS examinations were collected sequentially during a 6-month period, retrospectively. PAD patients included those with lifestyle-limiting intermittent claudication warranting revascularization and patients with critical limb ischemia, defined as ischemic rest pain, gangrene, or a nonhealing ischemic ulcer. For each, tibial and popliteal artery peak systolic velocity (PSV) was measured at the proximal, mid, and distal segment of each artery, and a mean PSV for each artery was calculated. Mean PSV, ankle-brachial indices, peak ankle velocity (PAV), average ankle velocity (AAV), mean tibial velocity (MTV), and ankle-profunda index (API) were compared between the two groups using independent t-tests. PAV is the maximum PSV of the distal peroneal, posterior tibial (PT), or anterior tibial (AT) artery; AAV is the average PSV of the distal peroneal, PT, and AT arteries; MTV is calculated by first averaging the proximal, mid, and distal PSV for each tibial artery and then averaging the three means together; API is the AAV divided by proximal PSV of the profunda. RESULTS: DUS was available in 103 patients with PAD (68 patients with critical limb ischemia and 35 patients with intermittent claudication) and 68 controls. Mean ankle-brachial index in the PAD group was 0.64 ± 0.25 compared with 1.08 ± 0.09 in controls (P = .006). Mean PSVs were significantly lower in PAD patients than in controls at the popliteal (64.6 ± 42.2 vs 76.2 ± 29.6; P = .037), peroneal (34.3 ± 26.4 vs 53.8 ± 23.3; P < .001), AT (43.7 ± 31.4 vs 65.4 ± 25.0; P < .001), and PT (43.4 ± 42.3 vs 74.1 ± 30.6; P < .001) and higher at the profunda (131.5 ± 88.0 vs 96.2 ± 44.8; P = .001). Tibial parameters including PAV (52.6 ± 45.0 vs 86.9 ± 35.7; P < .001), AAV (37.4 ± 26.4 vs 64.5 ± 21.7; P < .001), MTV (41.7 ± 30.4 vs 65.4 ± 21.7; P < .001), and API (0.43 ± 0.45 vs 0.75 ± 0.30; P < .001) were significantly lower in the PAD group than in controls. Nonoverlapping 95% confidence interval reference ranges were established for severe PAD and non-PAD controls. CONCLUSIONS: This study aims to characterize lower extremity arterial PSVs and ankle parameters in severe PAD and non-PAD controls. These early criteria establish reference ranges to guide vascular laboratory interpretation and clinical decision-making.