REHEARSAL Using Patient-Specific Simulation to Improve Endovascular Efficiency.

OBJECTIVE: To determine whether rehearsal using patient-specific information loaded onto an endovascular simulator prior to carotid stenting improves procedural efficiency and outcomes. METHODS: Patients scheduled for carotid artery stenting who had adequate preoperative computed tomography (CT) imaging were considered for enrollment. After obtaining informed consent, patients were randomized to control versus rehearsal groups. Those in the rehearsal group had their CT scans loaded into an endovascular simulator (Angio Mentor) followed by case rehearsal by the attending on the simulator within 24 hours prior to the procedure; control patients underwent routine carotid stenting without rehearsal. Contrast usage, fluoroscopy time, and timing of procedural steps were recorded by a blinded observer during the actual case to determine benefit. RESULTS: Fifteen patients were enrolled, with 6 patients randomized to the rehearsal group and 9 to the control. All measures showed improvement in the rehearsal group: Mean contrast volume (59.2 vs 76.9 mL), fluoroscopy time (11.4 vs 19.4 minutes), overall operative time (31.9 vs 42.5 minutes), time to common carotid sheath placement (17.0 vs 23.3 minutes), and total carotid sheath dwell time (14.9 vs 19.2 minutes) were all lower (more favorable) in the rehearsal group. The study was terminated early due to the lack of simulator access, and all P values were thus greater than .05 due to the lack of power. No strokes or other adverse events occurred in either group. CONCLUSION: Case-specific simulator rehearsal using patient-specific imaging prior to carotid stenting is associated with numerically less contrast usage, operative time, and radiation exposure, although this study was underpowered.

Successful Use of Nellix and Endovascular Aortic Sealing Technology for Treatment of Aortic Rupture in a Porcine Model.

BACKGROUND: Endovascular aortic sealing (EVAS) represents a recent transformation in approach for treatment of aortic aneurysms. Initial reporting has shown that EVAS using the Nellix device is safe with similar complication rates to standard endovascular aortic repair (EVAR). What remains unknown is how EVAS technology will behave in the ruptured setting. The purpose of this report is to discuss how EVAS system and endobag technology behave when deployed in a porcine model of aortic rupture. METHODS: A controlled left retroperitoneal rupture was created in 20 large swine. Following rupture, an EVAS system was deployed across the rupture site to seal the area. The primary end point was seal from ongoing hemorrhage. Other parameters were examined to include endobag extravasation, aortic wall pressure measurements and device behavior in a live tissue model. RESULTS: Of the EVAS systems used, 15 Nellix (Endologix, Irvine, CA) devices and 5 novel EVAS systems were used. Of the correctly deployed devices, 100% sealed the rupture (n = 19). One device was deployed above the rupture site, and seal was not achieved secondary to malpositioning. Endobag extravasation was seen with an average protrusion of 7.7 mm. No other areas of aortic injury were noted secondary to endobag trauma. Pressure recording from behind the endobag indicates loss of pulsatile flow to the aortic wall with polymer curing. CONCLUSIONS: Endovascular aortic sealing for rupture is feasible and performs well in a porcine model of aortic rupture. Polymer extravasation is seen and may be controllable by the implanter. Once the polymer has cured, pulsatile aortic wall pressure is no longer present. EVAS represents an emerging technology for treatment of aortic rupture.

A diagnostic evolution: surgical experience with popliteal artery entrapment syndrome at a military tertiary referral center.

BACKGROUND: Popliteal artery entrapment syndrome (PAES) is an increasingly encountered disorder that typically presents as claudication in young and active individuals. However, despite the increased recognition, accurate preoperative diagnosis can be difficult. The objective of this study was to describe the surgical assessment and outcomes of patients treated for PAES. METHODS: Retrospective case series of all patients managed surgically for a diagnosis of PAES at the San Antonio Military Medical Center from 2005 to 2013. RESULTS: Over 8 years, PAES was surgically treated in 25 consecutive limbs of 15 patients (mean age, 35; range, 21-49) in a military tertiary medical center. Type III was the most common variant (n = 13, 52%), followed by type VI (n = 7, 28%). Most patients presented with class I or II ischemia (88%), with anterolateral symptoms (56%), and were referred by orthopedics (66%). Diagnostic work-up included stress ankle-brachial indices, magnetic resonance imaging (MRI) and provocative angiography. Sixty-three percent of limbs with negative MRI demonstrated findings consistent with either type III or V PAES. Tendon release was used in those with types III and V, whereas liberal myectomy was used in those with types I, II, or VI. Two patients required revascularization. At a median follow-up of 126 days (range, 25 days-7 years), 83% of patients with type III demonstrated partial resolution of symptoms. Only 27% of patients without an identifiable muscle slip had clinical improvement. CONCLUSIONS: Despite modern imaging, open surgical exploration remains the definitive diagnostic modality for PAES. Patients with a muscular or tendinous slip identified intraoperatively have the best clinical outcomes. Those with no identifiable muscle slip (functional entrapment) are less likely to demonstrate clinical improvement. Further evaluation on outcomes in the management in PAES is warranted.

A technique for endograft relining of a type IV endoleak using a surgeon-modified internal gate.

Type IV endoleaks represent a rare etiology of late endograft failure; however, depending on the location, they can be extremely challenging to repair with endovascular solutions. We present a method of endograft relining that preserves antegrade limb perfusion, avoids extra-anatomic reconstructions, and ensures complete endograft exclusion.

Mechanism of stent failure in a patient with fibromuscular dysplasia following renal artery stenting.

Endovascular techniques used in the management of renal artery stenosis (RAS) have unique complications, to include stent facture, thrombosis, aneurysm formation, migration, and in-stent restenosis. Described here is an unusual complication of renal artery obstruction and recurrent hypertension without progressive loss of renal function, secondary to intermittent arterial kinking with respiratory and cardiac motion in a patient with fibromuscular dysplasia. This mechanical complication has implication not only in successful endovascular treatment of RAS, but raises questions regarding the alterations in dynamic motion with the cardio-respiratory cycle in stented visceral arteries in other vascular pathologies requiring renal artery stenting (i.e., juxtarenal or pararenal aortic aneurysms).

Magnetic resonance imaging: occult popliteal artery entrapment syndrome in a young soldier.

BACKGROUND: Popliteal artery entrapment syndrome (PAES) is frequently misdiagnosed because of symptom overlap with other conditions and lack of a definitive diagnostic modality. The incidence is widely variable, although it should be considered in all patients under 50 years with symptoms of lower extremity claudication. Long-term sequelae of PAES include critical limb ischemia, arterial occlusion, and aneurysm formation caused by repetitive external compression. METHODS: We review the case of a 27-year-old soldier originally treated for exertional compartment syndrome with fasciotomies without relief of symptoms. Magnetic resonance imaging (MRI) failed to demonstrate an aberrant slip of the gastrocnemius muscle, which was ultimately found and released on surgical exploration. RESULTS: Surgical exploration and release of an aberrant band of gastrocnemius muscle through a medial approach resulted in significant relief of symptoms and improvement of walking distance. CONCLUSIONS: Healthy athletes without peripheral vascular disease and symptomatic calf and foot claudication should have an early referral to vascular surgery. The risk of false-negative MRI warrants further investigation into provocative, noninvasive imaging modalities to properly classify PAES. This report reviews the literature to discuss the diagnostic challenges, natural history of disease, and surgical interventions for PAES.

Endovascular aortoiliac reconstruction to allow excision of an infected axillobifemoral bypass.

Axillofemoral graft reconstructions were initially intended to restore lower extremity perfusion in high-risk patients with symptomatic aortoiliac atherosclerotic occlusive disease. However, these reconstructions are now relegated to "bailout" procedures for infected grafts or high-risk critical limb ischemia patients that fail endovascular therapy. Infection of an extra-anatomic bypass graft is a challenging complication as it occurs in poor operative candidates with limited revascularization options and failure has a high rate of amputation and mortality. Described is a novel approach using endovascular reconstruction to treat symptomatic Trans-Atlantic Inter-Society Consensus-II type D aortoiliac lesions allowing for complete excision of an infected axillobifemoral bypass.

Correlation of intravascular ultrasound and computed tomography scan measurements for placement of intravascular ultrasound-guided inferior vena cava filters.

OBJECTIVE: The single puncture intravascular ultrasound (IVUS)-guided bedside placement of inferior vena cava (IVC) filters has been shown to be an effective technique. The major disadvantage of this procedure is a steep learning curve that can lead to an increased risk of filter malposition. In an effort to increase the safety and efficacy of IVUS-guided bedside IVC filter placement, we proposed that preoperative planning could reduce the incidence of IVUS-guided filter malpositions. As a first step, we examined the correlation between preoperative abdominal computed tomography (CT) scan measurements and intraprocedural IVUS derived measurements of vena cava anatomy and its surrounding structures. As a second step, we attempted to determine the safety of this protocol by assessing the incidence of malposition. METHODS: A retrospective review of prospectively collected data was performed on all patients receiving bedside IVUS-guided filters from July 1, 2010 to August 31, 2011. Measurements of the IVC length from the atrial-IVC junction to the midportion of the crossing right renal artery, the lowest renal vein, and iliac vein confluence were obtained prior to IVC filter placement by both CT-based measurement, as well as intraprocedural IVUS pullback lengths. Regression analysis (significant for P < .05) was used to determine the correlation between these imaging modalities. RESULTS: Forty-six patients had adequate CT scans available to perform the analysis and were candidates for bedside IVUS-guided IVC filter placement. All IVUS-guided filters were placed using a single puncture technique with the Cook Celect Filter. This study found there was a close correlation between IVUS and CT derived measurements of the right atrium to right renal artery distance, lowest renal vein distance, and iliac confluence distance. In addition, we found that the IVUS distances from the atrial-IVC junction to the right renal artery and lowest renal vein were statistically similar. Nine patients had 10 vascular anatomic variations, all identified by both IVUS and CT. There were no complications or malpositions of IVC filters using this protocol. CONCLUSIONS: These data suggest that IVUS pullback measurements from the right atrium used in combination with preprocedure CT derived measurements of the distance from the right atrium to the lowest renal vein and iliac vein confluence provide an accurate roadmap for the placement of bedside IVC filters under IVUS guidance. We provide a method for organizing this information in a preplanning document to aid this procedure. We suggest this easily employed technique be more fully utilized to help decrease the incidence of malpositioned filters using single puncture IVUS guidance.

The influence of aneurysm size on anatomic suitability for endovascular repair.

OBJECTIVES: It has been proposed that the threshold for repair of abdominal aortic aneurysms (AAAs) suitable for endovascular repair (EVAR) be lowered. A critical step in this pathway is determining whether smaller AAAs are more likely to be anatomically suitable for EVAR; that is, whether suitability is lost as the AAA grows. METHODS: Patients who underwent ultrasound (US) imaging for asymptomatic AAAs at the University of Rochester Medical Center between January 1, 2003, and January 31, 2007, were identified. All those who had an abdominal/pelvic computed tomography (CT) scan ≤ 3 months of the US imaging were identified. CT scans were reviewed using predefined criteria to assess anatomic suitability for conventional EVAR (ie, without consideration of debranching). RESULTS: Of 3005 aortic US studies performed during this period, 221 had CT scans showing infrarenal aneurysms. Of these, 168 patients (76%) were candidates for EVAR and 52 (24%) were not, most commonly due to a short neck (40; 77% of excluded). Size measured by CT scanning (mean, 53 ± 11 mm) averaged 4 mm larger than by US imaging (mean, 49 ± 10 mm; r(2) = 0.66; P < .0001). Aneurysm size measured by CT scanning (P < .0001) or US imaging (P < .0001) correlated with anatomic suitability for EVAR. Mean sizes for those suitable were 52 ± 9 mm by CT and 48 ± 7 mm by US imaging, whereas mean sizes for those not suitable were 58 ± 10 mm by CT and 53 ± 8 mm by US imaging. Receiver operating characteristic curve analysis demonstrated that an US cutoff of 4.87 mm best predicted anatomic suitability (86.2% if smaller, 64.8% if larger), whereas a CT cutoff of 57.0 mm best predicted suitability (84.7% if smaller, 63.2% if larger). CONCLUSIONS: Aneurysm size measured by CT averaged 4 mm larger than by US imaging. Larger aneurysms are less likely to be anatomically suitable for EVAR, but the rate of suitability does not appreciably decrease until the aneurysm measures 49 mm by US imaging or 57 mm by CT scanning. This implies that waiting until the aneurysm reaches currently accepted size criteria for repair does not result in "missing the window" for EVAR; in other words, just as many patients are anatomically suitable for EVAR at currently accepted size cutoffs than if earlier intervention had been done.

Therapy of renal artery aneurysms in New York State: outcomes of patients undergoing open and endovascular repair.

The purpose of this study was to evaluate changing trends in therapy and determinants of outcomes among patients with a renal artery aneurysm (RAA) undergoing surgical or endovascular repair in New York State (NYS). A retrospective cohort study of patients who underwent therapy for RAA in NYS from October 1, 2000, to December 31, 2006, was identified from the Statewide Planning and Research Cooperative System database. Regression models which included hospital and patient characteristics were created to identify predictors of untoward events following surgical or endovascular intervention. Over this time period 215 patients with RAA repairs were analyzed. In multivariate analysis, preoperative predictors of death included diabetes (adjusted odds ratio [OR]=57.8, 95% confidence interval [CI] 2.3-1,430.1, p=0.013), the presence of other aneurysms (adjusted OR=18.5, CI 1.5-234.4, p=0.024), and coagulopathy (adjusted OR=16.9, CI 3.4-393.1, p=0.03) but not repair type. Perioperative cardiac (adjusted OR=16.7, CI 1.4-197.1, p=0.026) and vascular device-related (adjusted OR=11.1, CI 1.003-123.0, p=0.049) complications were predictive of mortality. When patients with other aneurysms were excluded from analysis (n=153), there were no significant predictors of death. Ninety-one endovascular and 124 open surgical repairs were performed with a significant increase in the proportion of endovascular repairs performed over time (p<0.001), although since 2003 the proportion of both has been roughly equal. Diabetes (15.4% vs. 5.6%, p=0.018), chronic anemia (5.5% vs. 0.8%, p=0.04), and emergent admission (48.4% vs. 24.2%, p<0.001) were more prevalent among those with endovascular repair. Endovascular therapy was associated with a lower incidence of complications, lower median length of stay (4 vs. 7 days, p<0.001), and lower rates of discharge to skilled nursing facilities (18.9% vs. 39.2%, p=0.001). There has been an increasing number of treated RAAs in NYS since 2000, with the increase being primarily in those treated by endovascular techniques. Whether this represents a true increase in RAA incidence requiring management or an extension of indications is unknown. Outcomes after endovascular repair were better than those after conventional surgery, although whether this was due to the technique of repair itself or preprocedural selection bias cannot be determined.

Subcapsular hepatic hematoma with right hepatic vein thrombosis: a complication of shock wave lithotripsy.

Extracorporeal shock wave lithotripsy (ESWL) is a well-established, safe and effective therapeutic modality for surgical treatment of urolithiasis. Hematoma is a rare complication of ESWL and, when it occurs, typically involves the kidney. We report the case of a 71-year-old woman who developed severe, persistent abdominal pain after ESWL for a 9-mm stone at the ureteropelvic junction. Post-treatment CT scan demonstrated a 13 x 6-cm subcapsular hepatic hematoma. A follow-up CT scan showed expansion of the hematoma and development of hepatic vein thrombosis. This finding, along with persistent abdominal pain and rising liver transaminases, led to surgical intervention. The patient's symptoms resolved and liver function returned to baseline following liver decompression.

Simulator assessment of innate endovascular aptitude versus empirically correct performance.

OBJECTIVE: Prior work has established that performance on an endovascular simulator incorporating tactile feedback (haptics) correlates with previous endovascular experience and can be improved by training. This study was designed to test the ability to define and measure innate endovascular aptitude and empirically correct performance and to determine whether these are two different things. METHODS: Subjects ranging in endovascular skill level from novice to expert were surveyed to determine video game experience and skill, endovascular level of training, and endovascular experience. They were then tested by using a standard protocol requiring timed advancement of a catheter and wire sequentially into each of three vessels arising from a simulated type I arch. Recorded trials were independently and blindly scored by two experienced endovascular faculty members by using a modification of a previously validated scale (Modified Reznick Scale; MRS). Summed scores were analyzed by frequency analysis and categorized as satisfactory and unsatisfactory on the basis of a clear bimodal distribution. Categorical outcome, time to task completion, and other variables were analyzed by means of linear regression, analysis of variance, and Welch modified two-sample t tests, as indicated. RESULTS: A total of 61 subjects were enrolled: 42% students, 8% technicians, 19% surgeons, 13% cardiologists, and 18% radiologists. Of these, 62% were considered novices and 30% experts on the basis of previous experience; 56% of subjects worked in an endovascular-related occupation. MRS scores were highly correlated between raters (P < .0001) and showed a clear bimodal distribution, with subjects in any endovascular occupation (including technicians) scoring significantly better than all others (P < .0001). Hours of video games played per week were correlated highly with completion times (P < .001) and MRS scores (P < .001). Measures of formal training (number of endovascular cases and occupation) correlated highly with completion times (all P < .03) and MRS scores (all P < .008). In comparing completion times vs MRS scores, three groups were apparent: unskilled-inexperienced, skilled-inexperienced, and skilled-experienced, corresponding primarily to senior subjects without endovascular experience, younger subjects without endovascular experience, and formally trained endovascular physicians, respectively. Those judged intermediate in aptitude reduced times to the lowest possible level before improving their MRS scores. CONCLUSIONS: Although inherently subjective, the MRS yields reproducible scores that correlate with endovascular experience and formal training. Experts and novices with extensive video game experience achieve short completion times, whereas high MRS scores are achieved only by formally trained subjects. Innate endovascular aptitude and empirically correct performance may be two separate things, and aptitude may be acquirable through (or identified by) extensive nonmedical video game experience.