Frequency of perigraft hygroma after open aortic reconstruction.

OBJECTIVE: The incidence of perigraft hygroma (PGH) development after aortic reconstruction remains poorly defined and its clinical relevance is questionable. This study was designed to establish the incidence of and determine the risk factors associated with PGH formation and its outcomes. METHODS: Patients who underwent open aortic reconstruction for either aneurysmal or occlusive disease with an expanded polytetrafluoroethylene (ePTFE) or polyester graft from 2004 to 2018 were retrospectively reviewed (n = 262). Only those who had follow-up imaging 3 or more months after repair were included. Patients with mixed graft types were excluded. PGH was defined as a perigraft fluid collection of 30 mm or greater in diameter with a radiodensity of 30 or fewer Hounsfield units on computed tomography at a minimum of 3 postoperative months. Analysis was conducted between patients with and without PGH. RESULTS: One hundred forty patients met the inclusion criteria: 88 were treated with ePTFE and 52 with polyester grafts. Twenty-three patients (16.4%) were found to have radiologic evidence of PGH. PGH developed more frequently in patients with ePTFE (21/88 [23.9%]) compared with those with polyester grafts (2/52 [3.8%]) (P = .002). Mean PGH size was 63.5 ± 36.4 mm (range, 33-153 mm) and the average time to PGH detection 27.7 months (range, 3-112 months). Baseline characteristics were similar between the groups. Patients who developed PGH had larger aneurysms, more often received ePTFE grafts, had larger graft diameters, and had bifurcated grafts. The overall mortality was 32.1% at a mean follow-up of 5.2 years. The 5-year mortality rates were similar between patients with and without PGH (26.1% vs 18.8%; P = .41). Of the 23 patients with PGH, 4 (all with ePTFE) presented with symptoms related to the PGH. The average size of symptomatic and asymptomatic PGH were 11.5 and 4.8 cm, respectively. Mortality rates overall were similar between those with and without symptoms (50.0% vs 36.8%; P = .99). CONCLUSIONS: Nearly one-quarter of aortic reconstructions with ePTFE are associated with PGH formation compared with 4% with polyester. Clinically significant PGH-related symptom development occurs in 20%. Patient education and close surveillance are warranted. Manufacturer's device modification is needed.

Evaluating strategies for reducing scattered radiation in fixed-imaging hybrid operating suites.

OBJECTIVE: High-resolution fixed C-arm fluoroscopic systems allow high-quality endovascular imaging but come at a cost of greater scatter radiation generation and increased occupational exposure for surgeons. The purpose of this study was to evaluate the efficacy of two methods in reducing scattered radiation exposure. METHODS: There were 164 endovascular cases analyzed in three phases. In phase 1 (P1), baseline radiation exposure was calculated. In phase 2 (P2), staff used real-time radiation dose monitoring (dosimetry badges [RaySafe; Unfors, Hopkinton, Mass]). In phase 3 (P3), a software imaging algorithm was installed that reduced radiation (EcoDose software; Philips Healthcare, Best, The Netherlands). RESULTS: A total of 72 cases in P1, 34 cases in P2, and 58 cases in P3 were analyzed. Total mean dose-area product decreased across each phase, with statistical significance achieved for P1 vs P3 (mean ± standard error of the mean, 186,173 ± 16,754 mGy/cm2 vs 121,536 ± 11,971 mGy/cm2; P = .002) and P2 vs P3 (171,921 ± 26,276 mGy/cm2 vs 121,536 ± 11,971 mGy/cm2; P = .04), whereas total mean fluoroscopy time did not significantly differ across any phase. The radiation exposure to the primary operator did not change significantly from P1 to P2 but fell significantly in P3 (0.08 ± 0.02 mSv vs 0.03 ± 0.01 mSv; P = .02). The addition of dose reduction software had the most impact on endovascular aneurysm repair, with reductions in median room dose (P = .03) and primary operator exposure (P2 vs P3; 0.19 ± 0.04 mSv vs 0.03 ± 0.02 mSv; P < .01). CONCLUSIONS: Dose reduction software may be an effective technique to lower radiation exposure. Implementation of system-based strategies to reduce radiation is needed to reduce lifetime occupational radiation exposure for endovascular staff and to improve patient safety.

Characterizing tissue perfusion after lower extremity intervention using two-dimensional color-coded digital subtraction angiography.

OBJECTIVE: Digital subtraction angiography (DSA) of the peripheral arterial vasculature provides lumenographic information but only a qualitative assessment of blood flow. The ability to quantify adequate tissue perfusion of the lower extremities would enable real-time perfusion assessment during DSA of patients with peripheral arterial disease (PAD). In this study, we used a novel real-time imaging software to delineate tissue perfusion parameters in the foot in PAD patients. METHODS: Between March 2015 and June 2016, patients (N = 31) underwent lower extremity angiography using a two-dimensional perfusion (2DP) imaging protocol (Philips Healthcare, Andover, Mass). Of the 31 enrolled patients, 16 patients received preintervention and postintervention DSA images (18 angiograms), while contrast agent injection settings and the position of the foot, catheter, and C-arm were kept constant. The region of interest for perfusion measurements was taken at the level of the medial malleolus. Perfusion parameters included arrival time (AT) of contrast material, wash-in rate (WIR), time to peak (TTP) contrast intensity, and area under the curve (AUC). RESULTS: Patients (mean age, 67 years; male, 61%) undergoing 2DP had limbs classified as Rutherford class 3 (n = 9 limbs), class 4 (n = 11), and class 5 (n = 14) ischemia with a mean ankle-brachial index of 0.63. For the whole cohort, median (interquartile range) AT measured 5.20 (3.10-7.25) seconds; WIR, 61.95 (43.53-86.43) signal intensity (SI)/s; TTP, 3.80 (2.88-4.50) seconds; peak intensity, 725.00 (613.75-1138.00) SI; and AUC, 12,084.00 (6742.80-17,059.70) SI*s. A subset of patients had 2DP performed before and after intervention (n = 18 cases). A detectable improvement in SI and two-dimensional flow parameters was seen after intervention. Average AT of contrast material to the region of interest shortened after intervention with percentage decrease of 30.1% ± 49.1%, corresponding decrease in TTP of 17.6% ± 24.7%, increase in WIR of 68.8% ± 94.2% and in AUC of 10.5% ± 37.6%, decrease in mean transit time of 18.7% ± 28.1%, and increase in peak of 34.4% ± 42.2%. CONCLUSIONS: The 2DP imaging allows measurement of blood flow in real time as an adjunct to DSA. The AT may be the most sensitive marker of perfusion change in the lower extremity. Quantitative thresholds based on 2DP hold promise for immediate treatment effectiveness assessment in patients with PAD.

Increased risk of renal dysfunction with percutaneous mechanical thrombectomy compared with catheter-directed thrombolysis.

OBJECTIVE: Percutaneous mechanical thrombectomy (PMT) is regularly used in the treatment of both venous and arterial thrombosis. Although there has been no formal report, PMT has been linked to cases of reversible postoperative acute kidney injury (AKI). The purpose of this study is to evaluate the risk of renal dysfunction in patients undergoing PMT vs catheter-directed thrombolysis (CDT) for treatment of an acute thrombus. METHODS: This study is a retrospective review of all patients in a single institution with a Current Procedural Terminology code for PMT or CDT from January 2009 through December 2014. Each patient was grouped into one of the four following procedural categories: PMT only, PMT with tissue plasminogen activator (tPA) pulse-spray, PMT with CDT, or CDT only. Preoperative and postoperative creatinine and glomerular filtration rate (GFR) values were obtained for each patient. The RIFLE (Risk, Injury, Failure, Loss, and End-stage renal disease) criteria were used to categorize the extent of renal dysfunction. χ2 analysis, one-way analysis of variance, and unpaired t-test were used to assess significance. RESULTS: A total of 227 patients were reviewed, of which 82 were excluded due to either existence of preoperative AKI, history of end-stage renal disease, or lack of clinical data. Of the remaining 145 patients, 53 (37%) presented with arterial thrombosis (mean age, 62 years; 43% male) and 92 (63%) presented with venous thrombosis (mean age, 48 years; 45% male). The incidence of renal dysfunction was highest in the PMT/tPA pulse group (21%), followed by the PMT group (20%) and the PMT/CDT group (14%). CDT was not associated with renal dysfunction. PMT (P = .046), and PMT/tPA pulse (P = .033) were associated with higher rates of renal dysfunction than the CDT controls. The average preoperative GFR for the 22 patients who developed AKI was 53.7 ± 9.4 mL/min/1.73 m2. The minimum postoperative GFR within 48 hours was an average of 35 ± 16 mL/min/1.73 m2. Stratified by the RIFLE criteria, 13 (9%) patients progressed to the risk category, 6 (4%) progressed to the injury category, and 3 (2%) progressed to the failure category. None of the patients who developed renal dysfunction from PMT progressed to dialysis within the same admission period. CONCLUSIONS: The use of PMT as a treatment for vascular thrombosis is associated with renal dysfunction. Patients treated with PMT require postoperative vigilance and renal protective measures.

Comparative occupational radiation exposure between fixed and mobile imaging systems.

OBJECTIVE: Endovascular intervention exposes surgical staff to scattered radiation, which varies according to procedure and imaging equipment. The purpose of this study was to determine differences in occupational exposure between procedures performed with fixed imaging (FI) in an endovascular suite compared with conventional mobile imaging (MI) in a standard operating room. METHODS: A series of 116 endovascular cases were performed over a 4-month interval in a dedicated endovascular suite with FI and conventional operating room with MI. All cases were performed at a single institution and radiation dose was recorded using real-time dosimetry badges from Unfors RaySafe (Hopkinton, Mass). A dosimeter was mounted in each room to establish a radiation baseline. Staff dose was recorded using individual badges worn on the torso lead. Total mean air kerma (Kar; mGy, patient dose) and mean case dose (mSv, scattered radiation) were compared between rooms and across all staff positions for cases of varying complexity. Statistical analyses for all continuous variables were performed using t test and analysis of variance where appropriate. RESULTS: A total of 43 cases with MI and 73 cases with FI were performed by four vascular surgeons. Total mean Kar, and case dose were significantly higher with FI compared with MI. (mean ± standard error of the mean, 523 ± 49 mGy vs 98 ± 19 mGy; P < .00001; 0.77 ± 0.03 mSv vs 0.16 ± 0.08 mSv, P < .00001). Exposure for the primary surgeon and assistant was significantly higher with FI compared with MI. Mean exposure for all cases using either imaging modality, was significantly higher for the primary surgeon and assistant than for support staff (ie, nurse, radiology technologist) beyond 6 feet from the X-ray source, indicated according to one-way analysis of variance (MI: P < .00001; FI: P < .00001). Support staff exposure was negligible and did not differ between FI and MI. Room dose stratified according to case complexity (Kar) showed statistically significantly higher scattered radiation in FI vs MI across all quartiles. CONCLUSIONS: The scattered radiation is several-fold higher with FI than MI across all levels of case complexity. Radiation exposure decreases with distance from the radiation source, and is negligible outside of a 6-foot radius. Modern endovascular suites allow high-fidelity imaging, yet additional strategies to minimize exposure and occupational risk are needed.

Pulse volume recording does not enhance segmental pressure readings for peripheral arterial disease stratification.

BACKGROUND: Noninvasive vascular laboratory determinations for peripheral arterial disease (PAD) often combine pulse volume recordings (PVRs), segmental pressure readings (SPs), and Doppler waveform traces (DWs) into a single diagnostic report. Our objective was to assess the corresponding diagnostic values for each test when subjected to interpretation by 4 vascular specialists. METHODS: A total of 2226 non-invasive diagnostic reports were reviewed through our institutional database between January 2009 and December 2011. Data from noninvasive records with corresponding angiograms performed within 3 months led to a cohort of 76 patients (89 limbs) for analysis. Four vascular specialists, blinded to the angiographic results, stratified the noninvasive studies as representative of normal, <50% "subcritical," or ≥50% "critical" stenosis at the upper thigh, lower thigh, popliteal, and calf segments using 4 randomized noninvasive modalities: (1) PVR alone; (2) SP alone; (3) SP+DW; and (4) SP+DW+PVR. The angiographic records were independently graded by another 3 evaluators and used as a standard to determine the noninvasive diagnostic values and interobserver agreements for each modality. Statistical tests used include the Fleiss-modified kappa analysis, Kruskal-Wallis analysis of variance with Dunn's multiple comparison test, the Kolmogorov-Smirnov test, and the unpaired t-test with Welch's correction. RESULTS: Interobserver variance for all modalities was high, except for SP. When surveying for any stenosis (<50% and ≥50%), sensitivity (range 25-75%) was lower than specificity (range 50-84%) for all modalities. When surveying for critical stenosis only (≥50%), sensitivity (range 27-54%) was also lower than specificity (range 68-92%). Accuracy for detecting any stenosis with SP+DW was significantly higher than with PVR alone (66 ± 7% vs. 56 ± 12%, P = 0.017). There was a significant reduction in accuracy when including incompressible readings within the SP-only analysis compared with exclusion of incompressible vessels (P = 0.0006). However, the effect of vessel incompressibility on accuracy was removed with the addition of DW (P = 0.17) to the protocol. CONCLUSIONS: SP has the greatest interobserver agreement in evaluation of PAD and can be used preferentially for PAD stratification. Given the lower accuracy of PVR for detecting either subcritical or critical disease, PVR tests can be omitted from the noninvasive vascular examination without a significant reduction in overall diagnostic value and can be reserved for patients with incompressible vessels.

Successful management of life-threatening hemorrhage in a patient with synchronous lupus anticoagulant and factor VIII inhibitor.

Acquired factor VIII inhibitor is increasingly recognized as a cause of major soft tissue hemorrhage. The laboratory diagnosis can be obscured by the synchronous presence of the lupus anticoagulant, an extremely rare occurrence that has been reported outside the vascular surgery literature. Vascular surgeons should be knowledgeable of factor VIII inhibitor and aware that it can present with other blood disorders, making the diagnosis more difficult and management more complex. This case report describes such a patient and reviews the current literature on this topic.