Permissive hypertension during awake eversion carotid endarterectomy: a physiologic approach for cerebral protection.

BACKGROUND: Carotid endarterectomy (CEA) is often completed with general anesthesia and routine shunting; however, shunting is only required in a small group of at-risk patients to maintain adequate cerebral perfusion. Selective shunting during CEA is performed to normalize cerebral hemodynamics for patients determined to be at risk. Eversion CEA with selective shunting for neurologic dysfunction in patients that are awake/sedated is described, as well as routine use of permissive hypertension (PH), which uses standard cardiovascular medications to recruit the cerebral collateral network and reduce the need for shunting. STUDY DESIGN: A retrospective review of all CEA procedures performed from July 2006 to April 2013 was conducted. Procedures were divided into 3 groups: pre-PH phase (group A), PH-test phase (group B), and routine PH phase (group C). Operative reports and anesthesia documentation were reviewed for clamp time, need for shunting, and mean hemodynamics during each case. RESULTS: During the study period, 232 CEAs met inclusion criteria and were divided into 3 groups: group A (n = 75) was predominate reactionary shunting, group B (n = 41) was predominate reactionary blood pressure augmentation, and group C (n = 116) was pre-emptive PH. When combining groups A and B, the at-risk group consisted of 21 of 116 (18.1%) patients who had a neurologic compromise develop after clamping the internal carotid artery and required a shunt or altered blood pressure hemodynamics. In comparison with group C, routine use of PH pre-emptively before clamping as a standard intraoperative technique led to need for shunting in 1 of 116 (0.86%) (p ≤ 0.001) and significantly reduced operative time (p ≤ 0.0001). CONCLUSIONS: Routine use of PH during clamp time can recruit the cerebral collateral network and substantially reduce the at-risk group and need for shunting in awake/sedated patients.

Management of chronic mesenteric vascular insufficiency: an endovascular approach.

BACKGROUND: In patients with chronic mesenteric insufficiency (CMI), traditional bypass surgery carries a high operative mortality. Endovascular therapy for reconstruction of the mesenteric vascular system has high technical success but poor long-term patency. Secondary procedures are often mandatory for recurrent disease. The purpose of this study was to evaluate an endovascular-first treatment strategy for CMI, reserving open reconstruction for complex disease patterns without an endovascular option. STUDY DESIGN: Data for consecutive adult patients (N = 107) initially treated with endovascular techniques for CMI were reviewed. The management algorithm consisted of postoperative and biannual ultrasound and clinical follow-up. RESULTS: A total of 107 patients with CMI were treated from April 2004 through June 2010. Technical success for endovascular reconstruction was 100%. Long-term follow-up data were available on 90% of patients. After the index procedure, 57% of patients (n = 55) had complete resolution of the preoperative symptoms. During the management phase, 83% of patients had elevated velocities on duplex evaluation. During this interval, 53% of patients required no further intervention after the index procedure, and the remaining patients required an additional 78 procedures. Five patients required open revascularization for recurrent disease, and only 2 patients died from complications of mesenteric insufficiency. CONCLUSIONS: Endovascular management for CMI has a high technical success rate with low morbidity and mortality. Regular follow-up is essential to optimize patient outcomes. Ultrasound findings alone are a poor predictor of recurrent disease. Long-term success requires adaptation of a management program to elicit recurrent symptoms and offer prompt treatment.

Pharmacomechanical thrombolysis for phlegmasia cerulea dolens.

Phlegmasia cerulea dolens (PCD) is limb-threatening. Traditional treatments are very morbid. We examine the efficacy of percutaneous treatment of PCD. Between May 2005 and September 2008, we treated 21 limbs in 20 patients with lower extremity PCD who were candidates for thrombolysis. Diagnosis was by clinical examination and duplex ultrasound. Catheter access to the deep venous system was obtained through a popliteal vein. Therapy used pulse spray thrombolysis with tissue plasminogen activator (tPA). Infusion catheters and adjunctive percutaneous techniques were used as indicated. Postoperatively, patients were treated with systemic anticoagulation, compression hose, and interval follow-up. Limbs were graded according to the CEAP classification. Twenty patients (13 male) were treated with a mean age of 55.8 years. Nine patients had hypercoagulable states, four May Thurner syndrome, three a history of cancer, one postcolon resection, one acute myocardial infarction, and one postfemoral vein puncture. All patients had resolution of PCD without the need for open surgery. The initial tPA dose was 19.5 mg with pulse spray thrombolysis. Infusion catheters were required in 18 patients and used for 16.1 hours (range, 8 to 36 hours) until complete thrombolysis. Venous angioplasty was necessary in 14 patients with nine of these requiring venous stents. One patient required above-knee amputation despite successful treatment of her PCD. Mean follow-up was 10.7 months (range, 1 to 39 months). All patients demonstrated no or minimal residual thrombus and intact valvular function and a mean clinical CEAP score of 2.4. Percutaneous treatment of PCD produced excellent results with minimal morbidity.

Utility of basilic vein transposition for dialysis access.

Autologous arteriovenous access is the key to long-term success with hemodialysis and is strongly supported by the National Kidney Foundation's Dialysis Outcomes Quality Initiative guidelines. Basilic vein transposition (BVT) fulfills the need for a durable conduit with high patency and maturation rates. This retrospective review examines a single group's experience with this procedure. All patients undergoing BVT for hemodialysis with available follow-up data were reviewed. Telephone interviews were used to supplement clinical data where needed. Functional assisted patency was used as the end point for this procedure, and if the access was never used for dialysis, then the patency was considered zero. Secondary interventions performed while the access remained patent and in use were not considered detrimental to the patency reported. One hundred seventy BVTs in 162 patients were performed between November 1992 and October 2001. There were 87 women (53.7%) and 112 black patients (69.1%); hypertension was present in 138 patients (85.2%) and diabetes in 89 patients (54.9%). Each year, an increasing incidence of BVT was performed in our dialysis population. The BVT was performed as the first access in that extremity in 73 of the procedures (42.9%). Functional patency (primary assisted) was achieved in 40.0% at 2 years and 15.2% at 5 years. The mean assisted patency was 14.6 months. To maintain BVT patency, 40 percutaneous secondary interventions (69.0%) and 18 surgical revisions (31.0%) occurred in 32 patients (19.0%). Ligation for swelling was necessary in 4 patients (2.5%), and steal syndrome occurred in 3 patients (1.9%). BVT is a useful autologous procedure for hemodialysis and the preferred access alternative in patients without an adequate cephalic vein. Although patencies remain poor relative to other conventional arterial vascular procedures, BVT is our most durable hemodialysis access procedure and is often the only available autologous conduit for hemodialysis.

Are we undertreating carotid stenoses diagnosed by ultrasound alone?

Clinical management of carotid disease is primarily based on results of national trials (ACAS and NASCET) that used the distal internal carotid artery diameter as a reference. However, commonly accepted ultrasound (US) criteria for carotid stenosis were derived from the correlation of velocity measurements with angiographic bulb diameter reductions (BDR). This study was undertaken to compare the degree of carotid stenosis determined by conventional velocity criteria to the degree of stenosis measured by B-mode (gray scale) diameter at both the carotid bulb and at the distal internal carotid artery, and, second, to evaluate US imaging to derive distal diameter reductions (DDR) noninvasively. During a 3-month period patients referred for carotid US were prospectively analyzed for standard velocity criteria and plaque morphology. Minimum carotid diameter was measured by longitudinal and transverse B-mode measurements and compared to carotid bulb diameter and internal carotid diameter distal to all disease. B-mode diameter reductions were compared to the degree of stenosis determined by velocity criteria and to patient symptoms and the decision for carotid endarterectomy. In total, 131 carotid arteries in 74 patients were evaluated. Based on the University of Washington velocity criteria, lesions were classified as grade I (n = 61, 46%), IIA (n = 58, 44%), IIB (n = 7, 5%), or III (n = 5, 4%). BDR measured by B-mode predicted the grade of disease based on velocity criteria (p < 0.001) with an overall accuracy of 95%. With use of the B-mode for DDR (NASCET style), 18 patients exceeded the 60% threshold for surgical intervention. Of these, only 3 patients were symptomatic and were operated on. An additional 3 operated-on patients had an asymptomatic grade III stenosis, our usual threshold for intervention. Twelve additional patients were appropriate for surgical intervention by B-mode but were not treated based on conventional velocity criteria alone. Bulb diameter reduction by B-mode imaging correlates strongly with diameter reduction determined by velocity criteria, and independently predicts the grade of carotid disease. With this in mind, the accuracy of B-mode imaging may be extended to the measurement of carotid stenosis based on DDR. By B-mode criteria, many patients appropriate for intervention were not offered treatment based on conventional velocity criteria. Modern B-mode imaging provides a noninvasive method to obtain 'arteriographic equivalent'' measurements and should be added as a routine to carotid ultrasound interrogation.

Is three-dimensional computed tomography reconstruction justified before endovascular aortic aneurysm repair?

OBJECTIVES: The endovascular management of abdominal aortic aneurysm (AAA) relies on accurate preoperative imaging for proper patient selection and operative planning. Three-dimensional (3-D) computed tomography (CT) with reformatted images perpendicular to blood flow has gained popularity as a method of AAA assessment and image-based planning before endovascular aneurysm repair (EVAR). The current study was undertaken to determine the interobserver agreement of AAA measurements obtained with axial CT and reformatted 3-D CT and to compare the consistency of the 2 methods in selecting patients for EVAR. METHODS: Eight observers assessed the axial CT and reformatted 3-D CT scans for 5 patients with AAAs to determine whether the patients were candidates for EVAR. 3-D CT with multiplanar reformatted images was performed by Medical Media Systems (MMS). Each observer measured the length and diameter of the proximal neck, maximal AAA, aortic bifurcation, common iliac diameter, and aortic angulation. The proximal neck and common iliac arteries were also assessed for thrombus, calcification, and tortuosity. Agreement of the measurements on axial CT scans was compared with those on MMS CT scans by calculating the kappa statistic. Complete agreement was defined as kappa = 1.0. The limits of agreement between observers were also calculated. RESULTS: The cumulative interobserver agreement of MMS CT scans (kappa =.81) was greater than for axial CT scans (kappa =.59). The kappa value for each of the diameter measurements was greater with the MMS CT scans. In 79% of cases the observers' measurements were less than 2 mm from the mean with MMS CT, compared with 59% for axial CT. The kappa value for deciding whether a patient was an endograft candidate on the basis of aortic neck was greater with the MMS CT (0.92 vs 0.63). The limits of agreement between observers were also better with the MMS CT. CONCLUSIONS: The interobserver agreement in planning EVAR is significantly better with MMS CT compared with traditional axial CT. The routine use of MMS CT appears justified before EVAR to improve the accuracy and consistency of patient selection.

Percutaneous treatment of symptomatic central venous stenosis [corrected].

OBJECTIVES: The increased use of central venous access primarily for hemodialysis has led to a significant increase in clinically relevant central venous occlusive disease (CVOD). The magnitude of and the optimal therapy for CVOD are not clearly established. The purpose of this study is to define the problem of CVOD and determine the success of percutaneous therapy for relieving symptoms and maintaining central venous patency. METHODS: Patients presenting with disabling upper-extremity edema suggestive of central venous stenosis or occlusion during a 3-year period were evaluated by venography of the upper extremity and central veins. Percutaneous venous angioplasty (PTA) and/or stent placement was performed as clinically indicated. The success of therapy was assessed, and the patients were observed to determine the incidence of recurrence and additional procedures. Recurrent lesions underwent similar evaluation and treatment. RESULTS: A total of 32 sides were treated in 29 patients with a mean of 1.9 interventions per side treated. Hemodialysis-related lesions were the underlying cause in 87% with the remaining 13% related to previous central venous catheterization. The lesions involved the axillary, subclavian, and innominate veins with complete venous occlusion in six (19%) cases. Percutaneous angioplasty was followed by stent placement in six (19%) cases. The procedure was a technical success and was performed without complications in all cases (100%). Mean follow-up was 16.5 months (range, 4-36 months). On average, patient symptoms were controlled for 6.5 months after the initial intervention. Recurrent edema led to additional PTA in 20 (63%) cases. Fifty percent (n = 14) of patients with an arteriovenous fistula (AVF) experienced recurrent symptoms after initial and/or repeat PTA and required AVF ligation. Complete resolution after the initial PTA was predictive of long-term success. CONCLUSIONS: Central venous occlusive disease has emerged as a significant clinical problem. Percutaneous venous angioplasty can provide temporary symptomatic relief; however, multiple procedures are often required and long-term relief is rarely achieved.

Comparison of abdominal aortic aneurysm diameter measurements obtained with ultrasound and computed tomography: Is there a difference?

OBJECTIVES: Accurate diameter measurements of abdominal aortic aneurysm (AAA) with both computed tomography (CT) and ultrasound (US) are essential for screening, planning surgical intervention, and follow-up after endovascular repair. Often there is a discrepancy between measurements obtained with CT and US, and neither limit of agreement (LOA) nor correlation between the two imaging methods has been clearly established. The purpose of this study was to assess the paired differences in AAA diameter measurements obtained with CT and US in a large national endograft trial. METHODS: CT and US measurements were obtained from an independent core laboratory established to assess imaging data in a national endograft trial (Ancure; Guidant, Menlo Park, Calif). The study included only baseline examinations in which both CT and US measurements were available. Axial CT images and transverse US images were assessed for maximal AAA diameter and recorded as CT(max) and US(max), respectively. Correlations and LOA were performed between all image diameters, and differences in their means were assessed with paired t test. RESULTS: A total of 334 concurrent measurements were available at baseline after endovascular repair. CT(max) was greater than US(max) in 95% (n = 312), and mean CT(max) (5.69 +/- 0.89 cm) was significantly larger (P <.001) than mean US(max) (4.74 +/- 0.91 cm). The correlation coefficient between CT(max) and US(max) was 0.705, but the difference between the two was less than 1.0 cm in only 51%. There was less discrepancy between CT(max) and US(max) for small AAA (0.7 cm, 15.3%) compared with medium (0.9 cm, 17.9%) and large (1.46 cm, 20.3%) AAA; however, the difference was not statistically significant. LOA between CT(max) and US(max) (-0.45-2.36 cm) exceeded the limits of clinical acceptability (-0.5-0.5 cm). Poor LOA was also found in each subgroup based on AAA size. CONCLUSIONS: Maximal AAA diameter measured with CT is significantly and consistently larger than maximal AAA diameter measured with US. The clinical significance of this difference and its cause remains a subject for further investigation.

The utility of color duplex ultrasonography in the diagnosis of temporal arteritis.

PURPOSE: Temporal arteritis (TA) is frequently diagnosed with nonspecific clinical characteristics, followed by a temporal artery biopsy to confirm the presence of vasculitis. Consequently, numerous screening surgical biopsies are performed with a high negative-biopsy rate. A prospective study was performed evaluating color duplex ultrasound scan (CDU) as the preferred method for the diagnosis of vasculitis in the evaluation of suspected TA. METHODS: Thirty-two patients with suspected TA on the basis of clinical criteria were evaluated with CDU before a temporal artery biopsy. The presence of a hypoechoic "halo," suggesting edema of the inflamed vessel, and inflammatory stenoses were noted. Histologic examinations of standard temporal artery biopsies then were performed, and the results were compared with the CDU findings. In addition, a metaanalysis was performed to identify articles related to the use of ultrasound scan in the detection of TA. RESULTS: All patients completed a bilateral CDU examination of the temporal arteries, and in 75% of patients biopsied, no evidence of vasculitis was found at histologic examination. When CDU examined for halo alone as the determinant for disease, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), compared with histologic confirmation of TA, were 85.7%, 92.0%, 75.0%, and 95.8%, respectively. With the criteria for a halo sign present, an inflammatory stenosis present, or both present on CDU, the sensitivity, specificity, positive predictive value, and NPV were 100%, 80.0%, 58.3%, and 100%, respectively. CONCLUSION: CDU is a superior noninvasive method of determining the presence of vasculitis when compared with routine surgical biopsy. Examination of the temporal artery with CDU can effectively predict which patient will need surgical biopsy. The utility of CDU in the diagnosis of TA is maintained by a high sensitivity in detecting patients with the disease and also by a high NPV that can eliminate patients who would not benefit from biopsy.

The incidence and natural history of type I and II endoleak: a 5-year follow-up assessment with color duplex ultrasound scan.

PURPOSE: The purpose of this study was the demonstration of the value of color duplex ultrasound (CDU) scanning in the detection of type I endoleak (T1EL) and type II endoleak (T2EL), the correlation of Doppler scan waveform pattern to endoleak persistence or seal, and the description of the natural history of endoleak. METHODS: The study was a retrospective review of 83 patients who underwent periodic CDU scan and computed tomographic (CT) scan surveillance of the endograft and aneurysm sac after insertion of an aortic endograft for abdominal aortic aneurysm (AAA). Forty-one patients (49%) with an endoleak at anytime in the follow-up period form the basis of this report. RESULTS: T1EL was detected in all five patients with CDU and CT scans. T2EL was detected in 36 patients with CDU scan as compared with 18 patients with CT scan. With CT scan, endoleak was not detected when CDU scan showed no endoleak. Conversely, all CT scan--detected endoleaks were found with CDU scanning. The T2EL source artery was identified with CT scan in seven patients, whereas the source was identified in all 36 patients with CDU scan. Endoleak source did not correlate with outcome (seal or persistence). However, a to/fro Doppler scan waveform pattern was associated with spontaneous T2EL seal in seven of 12 patients, and a monophasic or biphasic waveform was associated with endoleak persistence in 14 of 17 patients (P =.023, with chi(2) test). Thirteen of 36 T2ELs underwent spontaneous seal by 6.2 +/- 2.8 months. T2ELs without increasing AAA diameter were observed. Eight patients with persistent T2EL present for more than 12 months did not undergo treatment. However, two patients underwent T2EL obliteration with coils because of AAA sac enlargement. T1EL of the distal attachment site was the initial endoleak identified in five patients, but seven patients harboring T2ELs had subsequent T1ELs develop. For the entire 83 patients, the combined T1EL and T2EL prevalence rate was 20% of patients at a 6-month follow-up period, but this rate increased to 50% after 24 months. The incidence rate of newly detected endoleaks and of spontaneous sealing was 24.4% at 12 months and 12.5% in longer-term follow-up period. CONCLUSION: CDU scan is effective in the identification of the type of endoleak, the delineation of the vessel involved, and the hemodynamic information not available with any other testing method. Endoleaks have a dynamic natural history characterized by a variable onset with changing branch vessel involvement and spectral flow patterns. Periodic long-term endograft surveillance with CDU scanning is necessary for following existing endoleaks and for detecting new ones. Corroboration of these findings in larger multicenter prospective trials will be needed to determine whether CDU scan analysis of endoleaks would be predictive of long-term success in endovascular AAA repair.