Mark M. Levy

Implantable Carotid Sinus Stimulator for the Treatment of Resistant Hypertension: Local Effects on Carotid Artery Morphology

BACKGROUND The Rheos System is a chronically implanted carotid sinus baroreflex activating system with a pulse generator and bilateral perivascular carotid sinus leads (CSLs) that is being evaluated in prospective clinical trials for the treatment of drug-resistant hypertension. We evaluated carotid artery structural integrity after implantation of the CSLs. METHODS To assess the effect of chronic CSL attachment, 29 CSLs were implanted on the common carotid arteries of eight sheep. The studies were terminated at 3 and 6 months postimplantation to assess anatomic and histologic changes. Additionally, 10 patients with resistant hypertension were enrolled in the Rheos Multicenter Feasibility Trial. Duplex ultrasound (DUS) was performed before device implantation and at 1 and 4 months postimplantation in this patient cohort. An independent core laboratory assessed all DUSs. RESULTS Ovine carotid angiography revealed no significant stenoses, while anatomic and histologic evaluations demonstrated electrode encapsulation in a thin layer of connective tissue with no evidence of stenosis, erosion, or inflammation. DUS evaluation revealed no significant increase in peak systolic velocities of the common and internal carotid arteries 1 and 4 months after initial implantation, indicating a lack of injury, remodeling, or stenosis. CONCLUSION The current data suggest that the CSLs used with the Rheos System are not associated with the development of carotid stenosis or injury. These short-term data support the concept of CSL placement and merit long-term investigation in a larger multicenter prospective trial.

Low Incidence of Pulmonary Embolism Associated With Upper-Extremity Deep Venous Thrombosis

BACKGROUND Most recent Chest 2008 guidelines counsel at least 3 months of anticoagulation for acute upper-extremity deep venous thrombosis (UEDVT). These guidelines are inconsistently followed, perhaps owing to relatively limited information regarding clinical outcomes among patients with UEDVT. Our institution maintains an UEDVT registry of consecutively encountered patients with sonographically confirmed UEDVT. We analyzed patient characteristics, treatment, and outcomes among these patients. METHODS Between April 2005 and November 2008, 300 consecutively encountered peripheral vascular laboratory patients with UEDVTs were identified. Data on UEDVT sonographic characteristics, patient demographics, anticoagulation treatment, pulmonary embolism (PE) incidence and diagnostic modality, hemorrhagic complications, and mortality were then extracted. RESULTS Among the 300 patients, there was deep venous obstruction in the distal innominate (n = 69), internal jugular (n = 146), subclavian (n = 161), axillary (n = 107), and brachial (n = 91) veins. Two hundred forty-six patients (82%) had UEDVTs identified as clearly acute or acute on chronic, based on sonographic appearance. Most patients with UEDVTs were symptomatic (n = 265, 88%). One hundred six patients had documented malignancy (35%), 92 were postoperative or trauma patients (31%), and 76 patients were obese (body mass index: >30, 25%). Additionally, 240 patients had associated or previous indwelling central venous lines or leads (80%). One hundred twenty-eight patients (43%) were initially anticoagulated with heparin, whereas 121 of these patients were converted to warfarin therapy (40%) for variable lengths of time. One hundred sixty-seven patients were not treated with anticoagulation (56%), of whom 16 had documented contraindication to anticoagulation. Although the anticoagulated subset of patients tended to be younger, the decision to anticoagulate patients correlated significantly with the sonographically documented acute nature of the deep venous thrombosis, and its extent. Six patients (2%) suffered PE in association with their UEDVT diagnosis. There was no PE-related mortality. However, among anticoagulated UEDVT patients, there were four patients who suffered intracranial hemorrhage resulting in three deaths, and an additional three patients who required rehospitalization for upper gastrointestinal (n = 2) or stomal (n = 1) hemorrhage. CONCLUSIONS Anticoagulation therapy is inconsistently used to treat UEDVT and most often used for patients with multiple vein segments involved and with sonographically acute UEDVT components. However, regardless of the decision to anticoagulate, the incidence of PE attributable to UEDVT is small (2%), regardless of treatment with anticoagulation. Given the observed mortality associated with anticoagulation in this fragile patient cohort, the risk-benefit analysis for anticoagulation does not favor routine anticoagulation among these patients.

Upper extremity deep venous thrombosis: reassessing the risk for subsequent pulmonary embolism.

BACKGROUND Although the incidence of upper extremity deep venous thrombosis (UEDVT) diagnoses has increased, anticoagulation therapy for UEDVT remains inconsistent and of variable duration. This study sought to analyze our institutions current treatment practices for UEDVT and assess the risk for subsequent pulmonary embolism (PE). METHODS Between April 2005 and July 2007, 200 consecutively encountered patients with UEDVTs were identified in the Peripheral Vascular Laboratory. Then, UEDVT location and sonographic characteristics, patient demographics, anticoagulation treatment, and PE incidence and mortality were examined. RESULTS Among the 200 patients with UEDVT, 156 (78%) had UEDVTs identified as clearly acute or acute on chronic, based on sonographic appearance. In all, 85% of the patients were symptomatic (n = 171). Among the patients, 71 (36%) had documented malignancy, 58 (29%) were postoperative or suffering from trauma, and 52 (26%) were obese (body mass index: >30). In addition, 153 (76%) had associated current or previous indwelling lines or leads. A total of 73 patients (36%) were put on anticoagulation therapy for variable periods. Younger age of the patient, duplex evidence of an acute deep venous thrombosis, and involvement of multiple named upper extremity venous segments were independent predictors of the decision to initiate anticoagulation therapy for patients with UEDVT. Two patients (1%) suffered PE, most likely the consequence of their UEDVTs. An additional two patients with UEDVT treated with coumadin died months after hospital discharge from intracranial bleedings after minor falls. CONCLUSION Currently, the clinical decision to initiate anticoagulation therapy for patients with UEDVT is most associated with the documented acute nature of the deep venous thrombosis by duplex ultrasonography, involvement of multiple venous segments, and younger age of the patient. The incidence of PE attributable to previously documented UEDVT is very small (1%), regardless of anticoagulant therapy. Anticoagulation therapy for UEDVT is most likely to be best suited to address the symptoms of UEDVT; its proposed use to decrease the very small risk of PE may be rarely indicated, and must be carefully weighed with the risks associated with therapeutic anticoagulation in this patient population.

Previous Hemodialysis Access Improves Functional Outcomes of the Proximal Radial Artery Fistula in Males

BACKGROUND The proximal radial artery fistula (PRA) has been established as an early viable surgical option for arteriovenous fistula creation. The overall assisted primary patency reported in the literature approaches 100% at 1 year. We hypothesize that this excellent patency does not represent a functional result when seen in light of successful cannulation and fistula utilization. METHODS We retrospectively queried our Veterans Administration Hospital operative database to identify 284 male patients who had 571 access procedures performed by a senior vascular surgeon attending (R.K.D.) from January 1, 2003, to December 31, 2008. Operative details, patient comorbidities, fistula maturation time (time to first cannulation), functional patency (date of access to abandonment, revision to another fistula type, conversion to a prosthetic graft, thrombosis of the fistula, conversion to peritoneal dialysis, renal transplant, or patient death), and total duration (creation of the fistula to the end of its functional patency) were collected and analyzed. RESULTS A total of 144 PRAs were placed during the study period. In all, 87 patients underwent primary proximal radial artery fistula (P-PRA) placement in a limb without previous access; 57 patients had a secondary proximal radial artery fistula (S-PRA) after a failed previous fistula or graft in the same limb. There were no differences between the 2 groups in terms of age, comorbidities, and operative details. A total of 91 patients (63.2%) were receiving hemodialysis at the time of P-PRA or S-PRA placement. Outcomes of P-PRA and S-PRA populations on hemodialysis were examined. There was increased cannulation success (33% vs. 55%; P = 0.00354, Fishers exact test), functional patency (755.2 ± 661.2 days vs. 405.4 ± 531.9 days; P = 0.0220, Wilcoxon two-sample test), and total duration (859.5 ± 650.7 days vs. 516.8 ± 547.2 days; P = 0.0361, Wilcoxon two-sample test) of S-PRA over P-PRA. There was no difference in endovascular interventions between the 2 groups (1.6 ± 1.0 interventions per access versus 1.1 ± 0.7 interventions per access; P = 0.2109, Wilcoxon two-sample test). Subgroup analysis (analysis of variance) of the S-PRA group indicated that a patent but failing previous access in the same arm was not superior in terms of successful cannulation, functional patency, or total duration when compared with a thrombosed previous access. CONCLUSIONS The PRA remains a viable first access procedure undertaken at our institution. Compared with the reported 12-month assisted primary patency of this fistula type, we found a small percentage of PRAs actually being accessed for successful hemodialysis treatment. The S-PRA appears to have a significantly higher successful cannulation rate, functional patency, and total duration time when compared with the P-PRA in patients receiving hemodialysis treatments. The mechanism of these improved outcomes is not known; considering patency or thrombosis of a previous access in the S-PRA group did not predict future access success in the same extremity.

DVT Surveillance Program in the ICU: Analysis of Cost-Effectiveness

Background Venous Thrombo-embolism (VTE – Deep venous thrombosis (DVT) and/or pulmonary embolism (PE) – in traumatized patients causes significant morbidity and mortality. The current study evaluates the effectiveness of DVT surveillance in reducing PE, and performs a cost-effectiveness analysis. Methods All traumatized patients admitted to the adult ICU underwent twice weekly DVT surveillance by bilateral lower extremity venous Duplex examination (48-month surveillance period – SP). The rates of DVT and PE were recorded and compared to the rates observed in the 36-month pre-surveillance period (PSP). All patients in both periods received mechanical and pharmacologic prophylaxis unless contraindicated. Total costs – diagnostic, therapeutic and surveillance – for both periods were recorded and the incremental cost for each Quality Adjusted Life Year (QALY) gained was calculated. Results 4234 patients were eligible (PSP – 1422 and SP – 2812). Rate of DVT in SP (2.8%) was significantly higher than in PSP (1.3%) – p<0.05, and rate of PE in SP (0.7%) was significantly lower than that in PSP (1.5%) – p<0.05. Logistic regression demonstrated that surveillance was an independent predictor of increased DVT detection (OR: 2.53 – CI: 1.462–4.378) and decreased PE incidence (OR: 0.487 – CI: 0.262–0.904). The incremental cost was

PC160 Common Femoral Artery Endarterectomy: Contemporary Results Using Eversion Endarterectomy vs Standard Endarterectomy With Patch

509,091/life saved in the base case, translating to

An implantable carotid sinus stimulator for drug-resistant hypertension: Surgical technique and short-term outcome from the multicenter phase II Rheos feasibility trial

29,102/QALY gained. A sensitivity analysis over four of the parameters used in the model indicated that the incremental cost ranged from

Pulmonary Embolism Risk Following Upper Extremity DVT in a Single-Center Series of 500 Consecutive Patients

18,661 to

Stimulateur implantable du sinus carotidien pour traitement de l’hypertension artérielle résistante : effet local sur la morphologie de la carotide

48,821/QALY gained. Conclusions Surveillance of traumatized ICU patients increases DVT detection and reduces PE incidence. Costs in terms of QALY gained compares favorably with other interventions accepted by society.

Experience With Eversion Endarterectomy of the Common Femoral Artery With Comparison With Standard Endarterectomy With Patch

Objectives: For over 50 years, standard endarterectomy with patch (SEP) of the common femoral artery (CFA) has been well described with durable results. Eversion endarterectomy (EE) uses a complete CFA transection above its bifurcation and subsequent end-to-end anastomosis. EE is potentially advantageous over SEP by avoiding prosthetic patch infection and easing future transfemoral access. With subjectively more focal femoral artery lesions encountered during the endovascular era, we reviewed our SEP and EE outcomes to see whether there were any differences between the two methods. Methods: We retrospectively identified all patients undergoing CFA endarterectomy by a single surgeon who adopted preferential EE at a single institution between 2007 and 2015. Patient demographics and surgical details were captured from the electronic medical record, including endarterectomy type and the performance of concurrent endovascular and/or bypass surgery. Complications and adverse events were recorded. Statistical comparison of means was performed using the t-test, and categoric variables were evaluated using the Fisher exact test. Results: Eighty-nine sequentially encountered patients underwent 97 endarterectomies of the CFA (68 SEP and 29 EE). More SEP than EE cases were performed concomitant with either bypass or stenting (62% vs 34%). Most patients were smokers (80% of SEP vs 93% of EE). Patients undergoing EE were older (67 vs 62 years; P 1⁄4 .01), with less hypertension (59% vs 79%; P 1⁄4 .04), and less chronic kidney disease (4% vs 27%; P 1⁄4 .01). The observed frequencies of diabetes, dyslipidemia, coronary artery disease, stroke, coagulopathy, and cancer were not significantly different among EE and SEP patients. The average follow-up duration was 28 months, longer among SEPs patients than EE patients (32 vs 20 months; P 1⁄4 .02). We observed favorable primary patency with EE (Table). There were no statistically significant differences observed among adverse events associated with SEP and EE patients (Fig): CFA restenoses (10% vs 3.4%), CFA thromboses (12% vs 0%), and wound infections (10% vs 7%). Conclusions: EE and SEP both offer reasonably durable outcomes for the treatment of focal femoral arterial occlusive disease. EE may offer an attractive alternative to SEP, potentially decreasing the risk of significant wound complications associated with prosthetic patch infections.