Stephane Elkouri

Arterial trauma during central venous catheter insertion: Case series, review and proposed algorithm

BACKGROUND Percutaneous catheterization is a frequently-used technique to gain access to the central venous circulation. Inadvertent arterial puncture is often without consequence, but can lead to devastating complications if it goes unrecognized and a large-bore dilator or catheter is inserted. The present study reviews our experience with these complications and the literature to determine the safest way to manage catheter-related cervicothoracic arterial injury (CRCAI). METHODS We retrospectively identified all cases of iatrogenic carotid or subclavian injury following central venous catheterization at three large institutions in Montreal. We reviewed the French and English literature published from 1980 to 2006, in PubMed, and selected studies with the following criteria: arterial misplacement of a large-caliber cannula (>/=7F), adult patients (>18 years old), description of the method for managing arterial trauma, reference population (denominator) to estimate the success rate of the therapeutic option chosen. A consensus panel of vascular surgeons, anesthetists and intensivists reviewed this information and proposed a treatment algorithm. RESULTS Thirteen patients were treated for CRCAI in participating institutions. Five of them underwent immediate catheter removal and compression, and all had severe complications resulting in major stroke and death in one patient, with the other four undergoing further intervention for a false aneurysm or massive bleeding. The remaining eight patients were treated by immediate open repair (six) or through an endovascular approach (two) for subclavian artery trauma without complications. Five articles met all our inclusion criteria, for a total of 30 patients with iatrogenic arterial cannulation: 17 were treated by immediate catheter removal and direct external pressure; eight (47%) had major complications requiring further interventions; and two died. The remaining 13 patients submitted to immediate surgical exploration, catheter removal and artery repair under direct vision, without any complications (47% vs 0%, P = .004). CONCLUSION During central venous placement, prevention of arterial puncture and cannulation is essential to minimize serious sequelae. If arterial trauma with a large-caliber catheter occurs, prompt surgical or endovascular treatment seems to be the safest approach. The pull/pressure technique is associated with a significant risk of hematoma, airway obstruction, stroke, and false aneurysm. Endovascular treatment appears to be safe for the management of arterial injuries that are difficult to expose surgically, such as those below or behind the clavicle. After arterial repair, prompt neurological evaluation should be performed, even if it requires postponing elective intervention. Imaging is suggested to exclude arterial complications, especially if arterial trauma site was not examined and repaired.

Most patients with abdominal aortic aneurysm are not suitable for endovascular repair using currently approved bifurcated stent-grafts.

Strict morphologic criteria must be used for patient selection to achieve durable success with endovascular aortic aneurysm repair (EVAR). The goal of this study was to assess morphologic suitability (MS) of abdominal aortic aneurysms (AAAs) for 2 currently approved bifurcated stent grafts and identify reasons for exclusion from EVAR. The authors reviewed the electronic charts of 1,795 consecutive patients who were diagnosed as having AAA between January 1999 and July 2001 at their institution. Three hundred and twenty patients had an AAA with a diameter of =5.0 cm, measured on computed tomography (CT). The records of 301 patients, 254 men, 47 women, with a mean age of 74 years were available for review, and these patients constituted the study cohort. Criteria used for MS included a proximal neck length =15 mm; neck diameter between 18 and 26 mm; neck angulation =60°; common or external iliac artery (CIA or EIA) diameters of 7–16 mm and 8–13 mm, respectively, for AneuRx (Medtronic Ave, Santa Rosa, CA) and Ancure (Guidant Cardiac and Vascular Division, Menlo Park, CA) bifurcated grafts. AAAs were suitable for AneuRx device in 14% of patients (43 of 301; 95% CI = 11–19%) and for Ancure in 5% (16 of 301; 95% CI = 3.1–9%). The main reason for exclusion was an inadequate proximal aortic neck (73%). The neck was too short in 49.5%, too wide in 64% and badly angulated in 12% of the patients. Iliac artery morphology precluded EVAR with AneuRx and Ancure devices in 52% and 80%. Both CIAs were too wide for EVAR in 43% and 77%, respectively. When iliac artery diameter =20 mm was accepted, iliac suitability for AneuRx increased from 49% to 70% and overall suitability increased from 14% to 20%. When more permissive criteria were used for MS (neck length =10 mm, neck diameter =30 mm, CIA =20), 39% of patients became candidates for EVAR. More than three fourths of the patients with an AAA =5.0 cm in size, seen in a tertiary referral center, are morphologically not suitable for EVAR using 2 currently approved bifurcated endografts. The main reasons for exclusion are a short or wide proximal aortic neck. Considerable changes in size of the devices and in proximal attachment techniques have to occur before most AAAs will be suitable for EVAR.

Endovascular repair of abdominal aortic aneurysms: initial experience with 100 consecutive patients.

OBJECTIVE To review early results of endovascular repair of abdominal aortic aneurysms (AAAs). PATIENTS AND METHODS The first 100 patients who underwent endovascular repair of AAA (EVAR) between June 26,1996, and October 31, 2001, at the Mayo Clinic in Rochester, Minn, were studied retrospectively to evaluate technical success, freedom from reinterventions, and early clinical outcome. RESULTS A total of 89 men and 11 women (mean +/- SD age, 76 +/- 7 years; range, 47-92 years) underwent EVAR. The procedure was successful in 97 patients. There was no early death. Major complications occurred in 25 patients. The 30-day technical success rate was 86% (95% confidence interval [CI], 77%-92%). The median intensive care unit stay was 1 day (range, 1-15 days), and the median hospital stay was 3 days (range, 1-35 days). Median follow-up was 7 months (range, 1-60 months). Endoleak (incomplete seal of the endovascular graft) at discharge was observed in 14 patients; 13 developed endoleak during follow-up. There were 23 reinterventions, 65% of which were percutaneous procedures. One aneurysm ruptured at 5 months, but the patient was successfully treated by open repair. Primary and secondary graft patency rates at 1 year were 83% (95% CI, 74%-93%) and 94% (95% CI, 87 %-99%), respectively. The freedom from reintervention rate at 1 year was 71% (95% CI, 59%-84%), with an overall success rate from EVAR of 92% (95% CI, 84%-100%). There were no differences in early patency, reinterventions, and success rates between unibody and modular devices. CONCLUSION EVAR can be performed with high technical success and low mortality rates; however, nonfatal complications and catheter-based reinterventions are frequent, and EVAR may not prevent aneurysm rupture. Although stent graft repair for high-risk patients is appealing, current data are insufficient to support EVAR as the preferred treatment of AAAs.

Measurements and detection of abdominal aortic aneurysm growth: Accuracy and reproducibility of a segmentation software

PURPOSE To validate the reproducibility and accuracy of a software dedicated to measure abdominal aortic aneurysm (AAA) diameter, volume and growth over time. MATERIALS AND METHODS A software enabling AAA segmentation, diameter and volume measurement on computed tomography angiography (CTA) was tested. Validation was conducted in 28 patients with an AAA having 2 consecutive CTA examinations. The segmentation was performed twice by a senior radiologist and once by 3 medical students on all 56 CTAs. Intra and inter-observer reproducibility of D-max and volumes values were calculated by intraclass correlation coefficient (ICC). Systematic errors were evaluated by Bland-Altman analysis. Differences in D-max and volume growth were compared with paired Students t-tests. RESULTS Mean D-max and volume were 49.6±6.2mm and 117.2±36.2ml for baseline and 53.6±7.9mm and 139.6±56.3ml for follow-up studies. Volume growth (17.3%) was higher than D-max progression (8.0%) between baseline and follow-up examinations (p<.0001). For the senior radiologist, intra-observer ICC of D-max and volume measurements were respectively estimated at 0.997 (≥0.991) and 1.000 (≥0.999). Overall inter-observer ICC of D-max and volume measurements were respectively estimated at 0.995 (0.990-0.997) and 0.999 (>0.999). Bland-Altman analysis showed excellent inter-reader agreement with a repeatability coefficient <3mm for D-max, <7% for relative D-max growth, <6ml for volume and <6% for relative volume growth. CONCLUSION Software AAA volume measurements were more sensitive than AAA D-max to detect AAA growth while providing an equivalent and high reproducibility.

Assessment of Wall Shear Stress Changes in Arteries and Veins of Arteriovenous Polytetrafluoroethylene Grafts Using Magnetic Resonance Imaging

The purpose of the study was to determine simultaneously the temporal changes in luminal vessel area, blood flow, and wall shear stress (WSS) in both the anastomosed artery (AA) and vein (AV) of arteriovenous polytetrafluoroethylene (PTFE) grafts. PTFE grafts were placed from the iliac artery to the ipsilateral iliac vein in 12 castrated juvenile male pigs. Contrast-enhanced magnetic resonance angiograpgy with cine phase-contrast magnetic resonance imaging was performed. Luminal vessel area, blood flow, and WSS in the aorta, AA, AV, and inferior vena cava were determined at 3 days (D3), 7 days (D7), and 14 days (D14) after graft placement. Elastin von Gieson staining of the AV was performed. The average WSS of the AA was highest at D3 and then decreased by D7 and D14. In contrast, the average WSS and intima-to-media ratio of the AV increased from D3 to D7 and peaked by D14. Similarly, the average area of the AA was highest by D7 and began to approximate the control artery by D14. The average area of the AV had decreased to its lowest by D7. High blood flows through the AA causes a decrease in average WSS and increase in the average luminal vessel area, whereas at the AV, the average WSS and intima-to-media ratio both increase while the average luminal vessel area decreases.

Source of Errors and Accuracy of a Two-Dimensional/Three-Dimensional Fusion Road Map for Endovascular Aneurysm Repair of Abdominal Aortic Aneurysm

PURPOSE To evaluate the accuracy and source of errors using a two-dimensional (2D)/three-dimensional (3D) fusion road map for endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm. MATERIALS AND METHODS A rigid 2D/3D road map was tested in 16 patients undergoing EVAR. After 3D/3D manual registration of preoperative multidetector computed tomography (CT) and cone beam CT, abdominal aortic aneurysm outlines were overlaid on live fluoroscopy/digital subtraction angiography (DSA). Patient motion was evaluated using bone landmarks. The misregistration of renal and internal iliac arteries were estimated by 3 readers along head-feet and right-left coordinates (z-axis and x-axis, respectively) before and after bone and DSA corrections centered on the lowest renal artery. Iliac deformation was evaluated by comparing centerlines before and during intervention. A score of clinical added value was estimated as high (z-axis < 3 mm), good (3 mm ≤ z-axis ≤ 5 mm), and low (z-axis > 5 mm). Interobserver reproducibility was calculated by the intraclass correlation coefficient. RESULTS The lowest renal artery misregistration was estimated at x-axis = 10.6 mm ± 11.1 and z-axis = 7.4 mm ± 5.3 before correction and at x-axis = 3.5 mm ± 2.5 and z-axis = 4.6 mm ± 3.7 after bone correction (P = .08), and at 0 after DSA correction (P < .001). After DSA correction, residual misregistration on the contralateral renal artery was estimated at x-axis = 2.4 mm ± 2.0 and z-axis = 2.2 mm ± 2.0. Score of clinical added value was low (n = 11), good (n= 0), and high (n= 5) before correction and low (n = 5), good (n = 4), and high (n = 7) after bone correction. Interobserver intraclass correlation coefficient for misregistration measurements was estimated at 0.99. Patient motion before stent graft delivery was estimated at x-axis = 8 mm ± 5.8 and z-axis = 3.0 mm ± 2.7. The internal iliac artery misregistration measurements were estimated at x-axis = 6.1 mm ± 3.5 and z-axis = 5.6 mm ± 4.0, and iliac centerline deformation was estimated at 38.3 mm ± 15.6. CONCLUSIONS Rigid registration is feasible and fairly accurate. Only a partial reduction of vascular misregistration was observed after bone correction; minimal DSA acquisition is still required.

Bicarbonates for the prevention of postoperative renal failure in endovascular aortic aneurysm repair: a randomized pilot trial.

Purpose. Contrast-induced nephropathy (CIN) can contribute to acute kidney injury (AKI) in patients undergoing endovascular aortic aneurysm surgery. We evaluated the incidence of AKI together with the evolution of early biomarkers of renal injury in patients receiving bicarbonates or NaCl 0.9%. Methods. This study involved endovascular aortic aneurysm surgery patients. Group A (n = 17) received bicarbonates 3 mL/kg/h for 1 h before the procedure and then 1 mL/kg/h until 6 h after surgery, whereas group B (n = 17) received NaCl 0.9% using the same protocol. Biomarkers of renal injury from urine (interleukin-18 (IL-18), neutrophil gelatinase-associated lipocalin (NGAL), N-acetyl-β-D-glucosaminidase (NAG), and kidney injury molecule 1 (KIM-1)) and blood (NGAL, cystatin C) were measured at baseline and 3, 24, and 48 h postoperatively. Results. AKI occurred in 1 patient (2.9%), in the bicarbonates group. IL-18, NAG, NGAL, and KIM-1 significantly rose in both groups after the surgery. There was a greater rise in NGAL and IL-18 after 3 h in the bicarbonates versus NaCl 0.9% group: 1115% versus 240% increase (P = 0.03) and 338% increase versus 1.4% decrease (P = 0.01). Conclusions. Despite significant elevation in biomarkers of renal injury, we demonstrated a low rate of AKI following endovascular aortic surgery.

Regional anesthesia for carotid surgery: less intraoperative hypotension and vasopressor requirement.

Regional anesthesia (RA) is the gold standard of neuromonitoring during carotid endarterectomy (CEA). Recent data show that RA for CEA is associated with fewer postoperative complications. The aim of the present study was to assess hemodynamic stability and vasoactive drug use for CEA performed under RA versus general anesthesia (GA). All patients undergoing CEA from January 2005 to January 2006 were identified from our prospective database. Electronic and paper charts were reviewed. Intraoperative monitoring data were reviewed retrospectively. Hypotension was defined as systolic blood pressure (SBP) <100 mm Hg and deemed prolonged if it lasted more than 10 min. Hypertension was defined as SBP >160 mm Hg. BP variation was defined as the difference between the highest and lowest SBP, and bradycardia as heart rate (HR) below 60. The data were expressed as means +/- standard deviation. Seventy-two consecutive patients underwent CEA: 25 under RA and 47 under GA. There was no difference in preoperative HR and BP. Most patients had symptomatic severe carotid stenosis (80% in RA vs. 85% in GA, nonsignificant). Intraoperatively, RA was associated with less BP variation (60 +/- 27 vs. 78 +/- 22 mm Hg, p = 0.005), bradycardia (5% vs. 63%, p < 0.001), hypotension (20% vs. 70%, p < 0.01), and prolonged hypotension (0% vs. 23%, p = 0.009) and more hypertension (80% vs. 47%, p = 0.007). Vasopressor requirements were less frequent under RA (20% vs. 77%, p < 0.001). There was no significant difference between groups in hypotension or hypertension episodes seen in the postoperative recovery room. RA was associated with less hypotension and less vasopressor used during CEA compared to GA. The improved hemodynamic stability may account for the lower incidence of complications after CEA.

Morphologic evaluation of ruptured and symptomatic abdominal aortic aneurysm by three-dimensional modeling.

OBJECTIVE To identify geometric indices of abdominal aortic aneurysms (AAAs) on computed tomography that are associated with higher risk of rupture. METHODS This retrospective case-control, institutional review board-approved study involved 63 cases with ruptured or symptomatic AAA and 94 controls with asymptomatic AAA. Three-dimensional models were generated from computed tomography segmentation and used for the calculation of 27 geometric indices. On the basis of the results of univariate analysis and multivariable sequential logistic regression analyses with a forward stepwise model selection based on likelihood ratios, a traditional model based on gender and maximal diameter (Dmax) was compared with a model that also incorporated geometric indices while adjusting for gender and Dmax. Receiver operating characteristic (ROC) curves were calculated for these two models to evaluate their classification accuracy. RESULTS Univariate analysis revealed that gender (P = .024), Dmax (P = .001), and 14 other geometric indices were associated with AAA rupture at P < .05. In the multivariable analysis, adjusting for gender and Dmax, the AAA with a higher bulge location (P = .020) and lower mean averaged area (P = .005) were associated with AAA rupture. With these two geometric indices, the area under the ROC curve showed an improvement from 0.67 (95% confidence interval, 0.58-0.77) to 0.75 (95% confidence interval, 0.67-0.83; P < .001). Our predictive model showed comparable sensitivity (64% vs 60%) and specificity (79% vs 77%) with current treatment criteria based on gender and diameter at the point optimizing the Youden index (sensitivity + specificity - 1) on the ROC curve. CONCLUSIONS Two geometric indices derived from AAA three-dimensional modeling were independently associated with AAA rupture. The addition of these indices in a predictive model based on current treatment criteria modestly improved the accuracy to detect aneurysm rupture.

Hand-assisted laparoscopic aorto-aortic bypass: Initial experience in a porcine model

Videoscopic surgical techniques have been developed to reduce morbidity of open aortic reconstructions. The advantage of hand-assisted laparoscopic surgery (HALS) technique is the introduction of the surgeons hand into the peritoneal cavity. The aims of this study were to assess the feasibility and to examine the learning curve, limitations, and pitfalls of the HALS technique to perform aortic reconstruction in a porcine model for training purposes. HALS aorto-aortic 8 mm polytetrafluoroethylene (PTFE) interposition grafts were placed in 12 pigs. Proficiency was judged by measuring operative time points, satisfactory completion of the operation, and the need to convert to open procedure. The strength of the relationship between order number in which a procedure was performed and the various surgical time point measures was described with the Spearman rank correlation. HALS aortic grafting was successful in the last 8 pigs. The first 2 pigs required conversion to open repair, and the graft of the third and fourth animals occluded early. Median operative time was 115 minutes (range: 75 to 205), median intestinal retraction time was 28 minutes (range: 10 to 40), median aortoiliac dissection time was 30 minutes (range: 20 to 60), and median aortic cross-clamp time was 48 minutes (range: 35 to 82). The Spearman rank correlations and p values between the order of the procedure and the intestinal retraction time, aortoiliac dissection time, clamping time, and total operative time were –0.62 (0.06), –0.47 (0.17), –0.69 (0.03), and –0.83 (0.03), respectively. HALS facilitates intestinal retraction and completion of laparoscopic aortoiliac dissection. It offers adequate exposure in pigs for aortic grafting and allows open sutured aortic anastomosis. The learning curve for HALS aortic surgery in a porcine model is short and within reach of surgeons with standard laparoscopic surgery skills, since no laparoscopic suturing is required. Training on this porcine model may be an efficient and safe way to introduce surgeons to HALS for aortoiliac reconstruction.