Nicholas J. Morrissey

Simulation improves resident performance in catheter-based intervention: results of a randomized, controlled study.

Objectives:Surgical simulation has been shown to enhance the training of general surgery residents. Since catheter-based techniques have become an important part of the vascular surgeons armamentarium, we explored whether simulation might impact the acquisition of catheter skills by surgical residents. Methods:Twenty general surgery residents received didactic training in the techniques of catheter intervention. Residents were then randomized with 10 receiving additional training with the Procedicus, computer-based, haptic simulator. All 20 residents then participated in 2 consecutive mentored catheter-based interventions for lower extremity occlusive disease in an OR/angiography suite. Resident performance was graded by attending surgeons blinded to the residents training status, using 18 procedural steps as well as a global rating scale. Results:There were no differences between the 2 resident groups with regard to demographics or scores on a visuospatial test administered at study outset. Overall, residents exposed to simulation scored higher than controls during the first angio/OR intervention: procedural steps (simulation/control) (50 ± 6 vs. 33 ± 9, P = 0.0015); global rating scale (30 ± 7 vs. 19 ± 5, P = 0.0052). The advantage provided by simulator training persisted with the second intervention (53 ± 6 vs. 36 ± 7, P = 0.0006); global rating scale (33 ± 6 vs. 21 ± 6, P = 0.0015). Moreover, simulation training, particularly for the second intervention, led to enhancement in almost all of the individual measures of performance. Conclusion:Simulation is a valid tool for instructing surgical residents and fellows in basic endovascular techniques and should be incorporated into surgical training programs. Moreover, simulators may also benefit the large number of vascular surgeons who seek retraining in catheter-based intervention.

Shifting Paradigms in the Treatment of Lower Extremity Vascular Disease: A Report of 1000 Percutaneous Interventions

Objectives:Catheter-based revascularization has emerged as an alternative to surgical bypass for lower extremity vascular disease and is a frequently used tool in the armamentarium of the vascular surgeon. In this study we report contemporary outcomes of 1000 percutaneous infra-inguinal interventions performed by a single vascular surgery division. Methods:We evaluated a prospectively maintained database of 1000 consecutive percutaneous infra-inguinal interventions between 2001 and 2006 performed for claudication (46.3%) or limb-threatening ischemia (52.7%; rest pain in 27.7% and tissue loss in 72.3%). Treatments included angioplasty with or without stenting, laser angioplasty, and atherectomy of the femoral, popliteal, and tibial vessels. Results:Mean age was 71.4 years and 57.3% were male; comorbidities included hypertension (84%), coronary artery disease (51%), diabetes (58%), tobacco use (52%), and chronic renal insufficiency (39%). Overall 30-day mortality was 0.5%. Two-year primary and secondary patencies and rate of amputation were 62.4%, 79.3%, and 0.5%, respectively, for patients with claudication. Two-year primary and secondary patencies and limb salvage rates were 37.4%, 55.4%, and 79.3% for patients with limb-threatening ischemia. By multivariable Cox PH modeling, limb-threat as procedural indication (P < 0.0001), diabetes (P = 0.003), hypercholesterolemia (P = 0.001), coronary artery disease (P = 0.047), and Transatlantic Inter-Society Consensus D lesion complexity (P = 0.050) were independent predictors of recurrent disease. For patients that developed recurrent disease, 7.5% required no further intervention, 60.3% underwent successful percutaneous reintervention, 11.7% underwent bypass and 20.5% underwent amputation. Patency rates were identical for the initial procedure and subsequent reinterventions (P = 0.97). Conclusion:Percutaneous therapy for peripheral vascular disease is associated with minimal mortality and can achieve 2-year secondary patency rates of nearly 80% in patients with claudication. Although patency is diminished in patients with limb-threat, limb-salvage rates remain reasonable at close to 80% at 2 years. Percutaneous infra-inguinal revascularization carries a low risk of morbidity and mortality, and should be considered first-line therapy in patients with chronic lower extremity ischemia.

An analysis of the outcomes of a decade of experience with lower extremity revascularization including limb salvage, lengths of stay, and safety

BACKGROUND Demographic and practice modality changes during the past decade have led to a substantial shift in the management of peripheral vascular disease. This study examined the effect of these changes using large national and regional data sets on procedure type, indications, morbidity, and on the primary target outcome: limb salvage. METHODS National Inpatient Sample (NIS) data sets and New York (NY) State inpatient hospitalizations and outpatient surgeries discharge databases from 1998 through 2007 were used to identify hospitalizations for lower extremity revascularization (LER) and major amputations. Patients were selected by cross-referencing diagnostic and procedural codes. Proportions were analyzed by chi(2) analysis, continuous variables by t test, and trends by the Poisson regression. RESULTS The national per capita (100,000 population, age >40 years) volume of major amputations decreased by 38%. The volume for national and regional use of endovascular LER doubled. The volume of open LER decreased by 67% from 1998 through 2007. Ambulatory endovascular LER grew in NY State from 7 per capita in 1998 to 22 in 2007. Interventions declined by 20% (93 to 75) for critical limb ischemia (CLI) but increased by nearly 50% for claudication. Outpatient data analysis revealed a fivefold increase in vascular interventions for CLI and claudication. Nationally, endovascular LER interventions quadrupled (8% to 32%) for CLI and doubled (26% to 61%) for claudication. A parallel reduction occurred in major amputations for patients with CLI (42% to 30%), for other PAD diagnoses (18% to 14%), and for claudication (0.9% to 0.3%). Although surgical interventions for CLI declined significantly for octogenarians from 317 to 240, outpatient interventions increased for CLI, claudication, and other diagnoses in all age groups. Comorbidities for patients treated in 2006 were substantially greater than those of a decade ago. For most procedures, cardiac and bleeding complications have significantly decreased during the last decade. Length of stay (LOS) declined from 9.5 to 7.6 days and the percentage of short (1-2 day) hospitalizations increased from 16% to 35%. CONCLUSION Although patients today, whether treated for claudication or CLI, have more comorbidities, the rates of amputation, the procedural morbidity and mortality, and LOS have all significantly decreased. Other variables, including changes in medical management and wound care, undoubtedly are important, but this change appears to be largely due to the widespread and successful use of endovascular LER or to earlier intervention, or both, driven by the safety of these techniques.

Insurance status predicts access to care and outcomes of vascular disease

OBJECTIVE To determine if insurance status predicts severity of vascular disease at the time of treatment or outcomes following intervention. METHODS Hospital discharge databases from Florida and New York from 2000-2005 were analyzed for lower extremity revascularization (LER, n = 73,532), carotid revascularization (CR, n = 116,578), or abdominal aortic aneurysm repair (AAA, n = 35,593), using ICD-9 codes for diagnosis and procedure. The indications for intervention as well as the post-operative outcomes were examined assigning insurance status as the independent variable. Patients covered under a variety of commercial insurers, as well as Medicare, were compared to those who either had no insurance or were covered by Medicaid. RESULTS Patients without insurance or with Medicaid were at significantly greater risk of presenting with a ruptured AAA compared to insured (non-Medicaid) patients; while insurance status did not seem to impact post-operative mortality rates for elective and ruptured AAA repair. The uninsured or Medicaid recipients presented with symptomatic carotid disease nearly twice as often as the insured, but stroke rates after CR did not differ significantly based on insurance status. Patients with Medicaid or without insurance were more likely to present with limb threatening ischemia than claudication. In contrast to AAA repair and CR, the outcomes of LER were worse in the uninsured and Medicaid beneficiaries who had higher rates of post-revascularization amputation compared to the insured (non-Medicaid) group. CONCLUSION Insurance status predicts disease severity at the time of treatment, but once treated, the outcomes are similar among insurance categories, with the exception of lower extremity revascularization. This data suggests inferior access to preventative vascular care in the Medicaid and the uninsured populations.

Lesion types and device characteristics that predict distal embolization during percutaneous lower extremity interventions

OBJECTIVE Distal embolization (DE) during percutaneous lower extremity revascularization (LER) may cause severe clinical sequelae. To better define DE, we investigated which lesion types and treatment modalities increase the risk for embolization. METHODS A prospective registry of LER from 2004 to 2009 was reviewed. All cases with runoff evaluated before and after intervention were included. Angiograms and operative reports were reviewed for evidence of DE. Interventions included percutaneous transluminal angioplasty (PTA), with or without stent placement, and atherectomy with four different devices. Chi-square analysis and Fishers exact test were used to assess significance. Patency rates were calculated using Kaplan-Meier analysis and compared using log-rank analysis. RESULTS There were 2137 lesions treated in 1029 patients. The embolization rate was 1.6% (34 events). Jetstream (Pathway, Kirkland, Wash) and DiamondBack 360 (Cardiovascular Systems Inc, St Paul Minn) devices had a combined embolization rate of 22% (8 of 36), 4 of 18 (22%) in each group, which was significantly higher than with PTA alone (5 of 570, 0.9%), PTA and stent (5 of 740, 0.7%), SilverHawk (ev3, Plymouth, Minn) atherectomy (14 of 736, 1.9%), and laser atherectomy (2 of 55, 3.6%; P < .001). There was a significantly higher rate of embolization for in-stent restenosis (6 of 188, 3.2%) and chronic total occlusions (15 of 615, 2.4%) compared with stenotic lesions (13 of 1334, 0.9%; P = .01). The embolization rate was significantly higher in Transatlantic Inter-Society Consensus (TASC) II C and D lesions compared with TASC A and B lesions (P = .018). DE rates were not affected by preoperative runoff status (P = .152). Patency was restored at the completion of the procedure in 32 of 34 cases of DE. The 24-month primary patency, assisted primary patency, and secondary patency in the DE group was 54.0% ± 11.9%, 70.0% ± 10.3%, and 73.2% ± 10.3%, respectively, and was 44.4% ± 1.7%, 61.5% ± 1.7%, and 68.2% ± 1.6%, respectively, when embolization did not occur (P > .05). Limb salvage was 72.6% ± 3.1% in lesions in which no DE occurred vs 83.3% ± 15.2% in lesions in which DE occurred (P = .699). CONCLUSIONS DE is a rare event that occurs more often with the Jetstream and DiamondBack 360 devices. In-stent and complex native lesions are at higher risk for DE. DE is typically reversible with endovascular techniques and has no effect on patency rates and limb salvage.

Percutaneous distal perfusion of the lower extremity after femoral cannulation for venoarterial extracorporeal membrane oxygenation in a small child.

Femoral cannulation in pediatric patients requiring extracorporeal membrane oxygenation (ECMO) is commonly associated with distal limb ischemia. Authors have previously reported successful lower limb perfusion using various open techniques to cannulate a distal lower extremity artery at the time of initial ECMO cannulation. These procedures include open femoral artery antegrade cannulation and distal posterior tibial artery retrograde cannulation in older children and adults. Such approaches require ample vessel diameters to accommodate an arteriotomy and catheter insertion and, therefore, are of limited use in smaller children. We hypothesized that after femoral artery cannulation for ECMO, a percutaneous technique of distal limb perfusion might offer unique advantages when treating lower extremity ischemia in small pediatric patients. We report a technique for percutaneous antegrade cannulation in a 4-year-old patient shortly after her primary cannulation for venoarterial ECMO via the femoral artery.

Independent case reportPercutaneous distal perfusion of the lower extremity after femoral cannulation for venoarterial extracorporeal membrane oxygenation in a small child

Femoral cannulation in pediatric patients requiring extracorporeal membrane oxygenation (ECMO) is commonly associated with distal limb ischemia. Authors have previously reported successful lower limb perfusion using various open techniques to cannulate a distal lower extremity artery at the time of initial ECMO cannulation. These procedures include open femoral artery antegrade cannulation and distal posterior tibial artery retrograde cannulation in older children and adults. Such approaches require ample vessel diameters to accommodate an arteriotomy and catheter insertion and, therefore, are of limited use in smaller children. We hypothesized that after femoral artery cannulation for ECMO, a percutaneous technique of distal limb perfusion might offer unique advantages when treating lower extremity ischemia in small pediatric patients. We report a technique for percutaneous antegrade cannulation in a 4-year-old patient shortly after her primary cannulation for venoarterial ECMO via the femoral artery.

Inducible Nitric Oxide Synthase Promoter Polymorphism Affords Protection Against Cognitive Dysfunction After Carotid Endarterectomy

BACKGROUND AND PURPOSE Cognitive dysfunction occurs in 9% to 23% of patients during the first month after carotid endarterectomy (CEA). A 4-basepair (AAAT) tandem repeat polymorphism (either 3 or 4 repeats) has been described in the promoter region of inducible nitric oxide synthase (iNOS), a gene with complex roles in ischemic injury and preconditioning against ischemic injury. We investigated whether the 4-repeat variant (iNOS(+)) affects the incidence of cognitive dysfunction after CEA. METHODS One-hundred eighty-five CEA and 60 spine surgery (control) subjects were included in this nested cohort analysis. Subjects underwent a battery of 7 neuropsychometric tests before and 1 day and 1 month after surgery. Multivariate logistic regression analyses were performed to determine if the iNOS promoter variant was independently associated with the incidence of cognitive dysfunction at 1 day and 1 month. Further, all right-hand-dominant CEA subjects were grouped by operative side and performance on each test was compared between iNOS(+) and iNOS(-) groups. RESULTS Forty-four of 185 CEA subjects had at least 1 iNOS promoter allele containing 4 copies of the tandem repeat (iNOS(+)). iNOS(+) status was significantly protective against moderate/severe cognitive dysfunction 1 month after CEA. Right-hand-dominant iNOS(+) CEA subjects undergoing left-side CEA performed significantly better than iNOS(-) subjects on a verbal learning test and those undergoing right-side CEA performed significantly better on a test of visuospatial function. CONCLUSIONS We demonstrate an iNOS promoter polymorphism variant provides protection against moderate/severe cognitive dysfunction 1 month after CEA. Further, this protection appears to involve cognitive domains localized ipsilateral to the operative carotid artery.

Aortoenteric Fistula: A Late Complication of Endovascular Repair of an Inflammatory Abdominal Aortic Aneurysm

Endovascular repair provides a reasonable alternative to open repair for the treatment of abdominal aortic aneurysms in select cases. Although the endovascular approach may be preferable for inflammatory aneurysms, aggressive surveillance is needed to monitor for long-term complications. A 61-year-old man underwent endovascular exclusion of a symptomatic inflammatory abdominal aortic aneurysm with an AneuRx bifurcated aortic prosthesis. He presented with gastrointestinal bleeding 51/2 months later and was found to have an aortoenteric fistula involving the third portion of the duodenum. The aneurysm had expanded significantly at the proximal neck. The patient underwent successful removal of the device, aortic ligation, and extraanatomic bypass. Aortoenteric fistula is a rare but now established complication of endovascular aneurysm repair. The pathophysiology in these cases remains unclear. The presence of inflammation and endoleak may predispose to further aneurysmal degeneration.

Determining Criteria for Predicting Stenosis With Ultrasound Duplex After Endovascular Intervention in Infrainguinal Lesions

BACKGROUND Studies examining duplex surveillance of lower extremity bypass grafts have defined a role for guiding graft re-intervention. The goal of this study is to determine the utility of duplex scanning to detect angiographic restenosis after endovascular therapy in patients with infrainguinal arterial disease. METHODS A prospective registry including all patients treated for lower extremity atherosclerotic disease between February 2004 and September 2008 was established. Patients were followed up with duplex ultrasound at 1, 3, 6, 12 months, and then annually. Patients receiving repeat angiograms were identified and angiogram and duplex data were abstracted. Velocity ratios (Vr) were calculated for each lesion by dividing the peak velocity within the lesion by the peak velocity proximal to the lesion. Logarithmic regression and receiver operator characteristic (ROC) curve analyses were used. RESULTS Repeat angiograms were performed on 345 lesions in 143 patients, and 254 lesions in 103 patients had a corresponding duplex ultrasound. Indications for the initial intervention were claudication (n = 62, 43.4%), rest pain (n = 23, 16.1%), and tissue loss (n = 58, 40.5%). A total of 178 superficial femoral artery (SFA) lesions, 59 popliteal lesions, and 17 tibial lesions were identified by surveillance duplex in 103 patients. In all, 70.5% of the intervened vessels that were studied were nonstented and the remaining 29.5% were stented. A total of 65% of the patients had diabetes. On determining correlations for peak systolic velocity (PSV) as measured by duplex ultrasound with degree of angiographic stenosis, strong correlation coefficients for SFA disease (R² = 0.84) and popliteal disease (R² = 0.88) were found. However, poor correlation was found in patients with tibial disease. When analyzing the lesions on the basis of Vr < 2.0, 11 of 86 (12.8%) had >70% angiographic stenosis. In lesions with ratios from 2 to 2.5, 12 of 13 (92.3%) had >70% angiographic stenosis and in lesions with ratios >2.5, 69 of 75 (92.0%) had >70% angiographic stenosis. ROC curve analysis showed that to detect ≥ 70% stenosis in the SFA, a PSV ≥ 204 cm/sec had a sensitivity of 97.6% and specificity of 94.7%. To detect ≥ 70% stenosis in the overall femoropopliteal region, a PSV ≥ 223 cm/sec had a sensitivity of 94.1% and specificity of 95.2%. CONCLUSIONS Duplex ultrasound surveillance correlates to the degree of angiographic stenosis on the basis of PSV in the SFA and popliteal region. Correlation in the tibial vessels is poor. Vr > 2.0 appear to correlate to angiographic stenosis of > 70%. ROC analysis shows that PSV can have sufficiently high sensitivity and specificity to predict angiographic stenosis in the femoropopliteal region.