Dale G. Wilson

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.

Patterns of Care in Hospitalized Vascular Surgery Patients at End of Life

Importance There is limited literature reporting circumstances surrounding end-of-life care in vascular surgery patients. Objective To identify factors driving end-of-life decisions in vascular surgery patients. Design, Setting, and Participants In this cohort study, medical records were reviewed for all vascular surgery patients at a tertiary care university hospital who died during their hospitalization from 2005 to 2014. Main Outcomes and Measures Patient, family, and hospitalization variables potentially important to influencing end-of-life decisions. Results Of 111 patients included (67 [60%] male; median age, 75 [range, 24-94] years), 81 (73%) were emergent vs 30 (27%) elective admissions. Only 15 (14%) had an advance directive. Of the 81 (73%) patients placed on comfort care, 31 (38%) had care withheld or withdrawn despite available medical options, 15 (19%) had an advance directive, and 28 (25%) had a palliative care consultation. The median time from palliative care consultation to death was 10 hours (interquartile range, 3.36-66 hours). Comparing the 31 patients placed on comfort care despite available medical options with an admission diagnosis–matched cohort, we found that more than 5 days admitted to the intensive care unit (odds ratio [OR], 4.11; 95% CI, 1.59-10.68; P < .001), more than 5 days requiring ventilator support (OR, 9.45; 95% CI, 3.41-26.18; P < .001), new renal failure necessitating dialysis (OR, 14.48; 95% CI, 3.69-56.86; P < .001), and new respiratory failure necessitating tracheostomy (OR, 23.92; 95% CI, 2.80-204; P < .001) correlated with transition to comfort care. Conclusions and Relevance Palliative care consultations may be underused at the end of life. A large percentage of patients were transitioned to comfort measures despite available treatment, yet few presented with advance directives. In high-risk patients, discussions regarding extended stays in the intensive care unit, prolonged ventilator management, and possible dialysis and tracheostomy should be communicated with patients and families at time of hospitalization and advance directives solicited.

Wound Care Management for Venous Ulcers

This chapter discusses the evaluation and management of venous ulcers. Successful treatment of venous ulcers depends upon following essential steps as based on current evidence in order to maximize success. These steps include confirming adequate arterial perfusion, eliminating edema, treating infection and biofilm, addressing venous reflux, alleviating venous obstruction, and reducing the impact of host risk factors and comorbidities. Such factors as reduction in obesity, improvement in calf muscle pump dysfunction, elimination of smoking, reduction of standing, and maximizing nutrition remain paramount to healing. Comprehensive wound centers may be better poised to offer this care in a coordinated fashion that helps incorporate a more patient-centric approach.

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.