Sean J. Hislop

Simulation Case Rehearsals for Carotid Artery Stenting

A case series of 5 patients is presented assessing the utility of simulation case rehearsals of individual patients for carotid artery stenting on an endovascular simulator. Simulated and operative device dimensions were similar. Results of subjective surveys indicated that face and content validity were excellent. The simulations predicted difficulty with vessel cannulation, however had difficulty predicting post-stent changes in bifurcation angulation. Our experience suggests that it may be feasible to use patient-specific CTA-derived data in the creation of a realistic case rehearsal simulation. The overall utility of this concept, including cost-benefit analysis, has yet to be determined.

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.

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.

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.