George H. Meier

Endoleak after aortic stent graft repair: Diagnosis by color duplex ultrasound scan versus computed tomography scan

PURPOSE The purpose of this study was to compare the accuracy of a color duplex ultrasound scan (CDU) to a computerized axial tomography scan (CT) in the diagnosis of endoleaks after stent graft repair of abdominal aortic aneurysms. METHODS The Endovascular Aneurysm Clinical Trial Core Laboratory records were reviewed from 117 concurrent CDU and CT studies that were performed in 79 patients who were implanted with the Endovascular Technologies stent graft device between December 1995 and January 1997. All of the studies were interpreted by the Core Laboratory as having the presence or the absence of an endoleak or as being indeterminate because of technical factors. Of the 117 videotaped CDU studies available for reexamination, 100 were reassessed for technical adequacy on the basis of the following criteria: a satisfactory imaging of the aneurysm sac and of the stent graft with gray scale, and both color and spectral Doppler scan evaluation for endoleak outside the endograft and within the aneurysm sac. RESULTS Of the 117 studies, 103 CDUs (88%) and 114 CTs (97%) were recorded as having the presence or the absence of an endoleak and 14 CDUs (12%) and 3 CTs (3%) were indeterminate. For the studies that were recorded to have the presence or the absence of an endoleak, the sensitivity, the specificity, the positive and the negative predictive values, and the accuracy of CDUs as compared with CTs were 97%, 74%, 66%, 98%, and 82%, respectively. Of the 100 CDU videotaped studies available for review, the following results were seen: (1) 93 CDUs had satisfactory B-mode images, (2) 76 had satisfactory color Doppler scan images to evaluate for endoleaks, (3) 55 had color Doppler scan assessment of the entire abdominal aortic aneurysm sac for endoleak, and (4) 27 had spectral Doppler scan waveform confirmation of suspected endoleaks. Only 19 CDU studies (19%) with all 4 criteria for complete assessment of endoleak were performed. CONCLUSION Although most of the CDU studies were technically suboptimal, the CDUs reliably identified endoleaks with an excellent sensitivity and a negative predictive value as compared with CT scans.

The natural history of autologous fistulas as first-time dialysis access in the KDOQI era

BACKGROUND Patients on hemodialysis depend on durable, easily maintained vascular access. The autologous arteriovenous fistula (AVF) has been the gold standard since the introduction of the Brecia-Cimino fistula in 1966 and is echoed in the current Kidney Disease Outcomes and Quality Initiative (KDOQI) guidelines. The purpose of this study is to determine the natural history of AVF in patients requiring first-time permanent access in a large academic vascular surgery practice. METHODS We performed a retrospective review of patients undergoing new access creation from January 1, 2005 to June 30, 2005. The study group consisted of patients with no prior permanent access that underwent AVF creation. Categorical data was compared using chi2 analysis, nominal data was compared using Student t-test, and patency was determined by Kaplan-Meier curves. RESULTS During the 6-month period, there were 80 first time AVF creations. The majority of patients were male (69%), African American (55%), and a history of diabetes (55%) and hypertension (96%). Seventy-five percent of patients were already undergoing hemodialysis via catheter access. Seventy-six percent of patients underwent preoperative vein mapping with a mean vein diameter of 3.1 mm. Twenty-six radiocephalic AVF (RCAVF) and 54 brachiocephalic AVF (BCAVF) were created with a mean follow-up of 278 days. At the end of follow-up, 38 (48%) AVF were being used for hemodialysis and only nine (11%) matured without the need for additional intervention. Mean time for AVF maturation was 146 days. Thirty AVF (37%) were abandoned, 16 (20%) of which were primary failures. Mean time to abandonment was 162 days. Twelve (15%) AVF remained patent but were never cannulated. The intervention rate was 1.33 interventions/patient/year and 75% of interventions were percutaneous. Kaplan-Meier analysis determined primary, primary-assisted, and secondary patency was 36% +/- 8.3, 55% +/- 6.5, and 55% +/- 6.5 at 1 year, respectively. Cumulative functional patency was 63% at 1 year. CONCLUSIONS In patients receiving a first time permanent access, we found that the majority were AVF and they resulted in low primary patency rates at 1 year and long maturation times. KDOQI encourages AVF creation in order to increase AVF use for dialysis, but the strategy of simply increasing the number being created may not lead to the desired result and potentially lead to an increase in catheter dependence.

Initial experience with venous stents in exertional axillary-subclavian vein thrombosis ☆ ☆☆ ★

PURPOSE Exertional thrombosis of the axillary and subclavian veins, also known as Paget-Schrötter syndrome, has been increasingly recognized in recent years as a cause of long-term morbidity. Recent aggressive approaches to treating Paget-Schrötter syndrome have suggested the association of early failure with residual subclavian vein stenosis. As a result, the use of endoluminal stents has been proposed as an aid to venous percutaneous transluminal angioplasty for this disorder. METHODS This report outlines the therapy of 11 consecutive patients with Paget-Schrötter syndrome who were treated at our institution between October, 1992, and December, 1995. Stents were placed when percutaneous transluminal angioplasty was unsuccessful at achieving an adequate residual lumen. RESULTS Stents were placed after initial thrombolysis in six patients and in late follow-up in two patients. Of the six patients who had stents placed at initial thrombolysis, first-rib resection was eventually performed in four. In two patients first-rib resection was not performed, and stent fracture occurred in both. Late patency was achieved in the stents of six of the eight patients. CONCLUSIONS Trials to evaluate stents as an adjunct to conventional therapy seem warranted. The use of stents alone without first-rib resection, however, appears to be associated with stent fracture.

Simplified captopril renography in diagnosis and treatment of renal artery stenosis.

To improve the diagnosis and forecast the response to surgery or renal angioplasty in patients with hypertension and renal artery stenosis, we employed a simplified captopril renography protocol in conjunction with renal arteriography in 94 clinically selected patients. Fifty hypertensive patients (group 1) with a high clinical likelihood of renovascular hypertension were evaluated using a simplified captopril renography protocol and renal angiography on the arterial side. Criteria for normal captopril renal scintigrams were established based on this original cohort and validated in an additional 44 clinically comparable patients (group 2). Renal revascularization or nephrectomy was performed in 39 patients, and success of the procedure was determined in the 34 patients for whom 3-month follow-up was available. In the 94 patients, 44 (47%) had renal artery stenosis. Simplified captopril renography was 91% sensitive and 94% specific in identifying or excluding renal artery stenosis in the combined group, with no difference in the diagnostic utility between groups 1 and 2, or in those with renal insufficiency (n=38) or those with bilateral disease (n=17). Scintigraphic abnormalities induced by captopril were strongly associated with cure or improvement in blood pressure control following revascularization or nephrectomy (15 of 18), while the lack of captoprilinduced changes was associated with failure of such intervention (13 of 16) (/?=0.0004). We conclude that simplified captopril renography is highly sensitive and specific in the diagnosis of renal artery stenosis in a clinically selected high-risk population and that the test accurately predicts the success or failure of therapeutic intervention. {Hypertension 1991; 18:)

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.

Reoperation for aortofemoral graft limb occlusion: Optimal methods and long-term results

To determine optimal methods of reoperation, experience with 157 secondary procedures for unilateral aortofemoral graft limb occlusion in 110 patients during a 16-year period was reviewed. In earlier years, inflow was reestablished by direct replacement of the graft limb or entire graft (11%); more recently, graft limb thrombectomy has been used most frequently (68%) with equal success, durability, and less morbidity. Femorofemoral grafts from the patent contralateral graft limb were employed in 18% of patients, usually those in whom thrombectomy was not attempted. Thrombolytic therapy (3%) appears to offer little advantage, is time-consuming, and occasionally causes significant complications. In addition to reestablishment of inflow, most patients also required revision of the femoral anastomosis to improve profunda femoris runoff; this was usually best accomplished by short segmental extension of the graft limb to the more distal deep femoral artery. Concomitant femoropopliteal bypass was done in 32% of patients and is indicated when preoperative angiography or specific intraoperative findings suggest inadequate profunda femoris outflow. An aggressive approach to reoperation appeared justified by long-term results (mean follow-up 37 months). Despite the need for repetitive reoperation in 26% of patients (two to five reoperations), graft limb patency was ultimately maintained in 78% and limb salvage achieved in 67% of patients, with an operative mortality rate of only 1.9%.

Subintimal angioplasty: Our experience in the treatment of 506 infrainguinal arterial occlusions

OBJECTIVE The treatment of patients with chronic arterial occlusions involving the superficial femoral artery has changed significantly with the incorporation of subintimal angioplasty (SIA) into vascular surgery practice. To more clearly define technical feasibility, patency, and clinical outcomes of SIA, we reviewed our cumulative experience. METHODS A retrospective review of all patients who underwent SIA of arterial occlusions originating in the superficial femoral artery was performed. Patient history, demographics, procedural details, and follow-up information were collected and analyzed. Patency, limb salvage, sustained improvement in claudication, freedom from surgical bypass, and survival were determined by Kaplan-Meier analysis. RESULTS From December, 2002, through July, 2006, 506 infrainguinal SIA procedures were performed in 472 patients with chronic arterial occlusion involving the superficial femoral artery. The mean age of patients treated was 69.4 +/- 11.9 years and the indication for intervention was critical limb ischemia in 63% of limbs (n = 317) and disabling claudication in 37% (n = 189). Forty-seven percent of limbs (n = 237) had isolated SFA occlusions, 40% (n = 205) had femoropopliteal occlusions, and 13% of limbs had occlusions beginning in the SFA and extending into the tibial arteries (n = 64). Technical success was achieved in 87% of procedures. Following successful SIA, the mean ankle-brachial index increased by 54%, from 0.50 +/- 0.16 to 0.77 +/- 0.23 (P < .0001). Median follow-up was 12.4 months (0-48 months) and 30-day mortality was 0.8%. Primary patency at 12 and 36 months was 45% (SE 3.0%) and 25% (SE 3.6%) respectively. Secondary patency was 76% (SE 2.6%) and 50% (SE 4.8%) at 12 and 36 months. Factors associated with reduced primary patency included femorotibial occlusions (HR 1.57, CI 1.05-2.36) and the presence of critical limb ischemia (HR 1.39, CI 1.02-1.89). Limb salvage in patients with critical limb ischemia was 75% (SE 5.9%) at 36 months. Freedom from surgical bypass in patients with either critical limb ischemia or disabling claudication was 77% (SE 4.1%) at 36 months. CONCLUSION SIA is an effective percutaneous technique for the revascularization of patients with lower extremity chronic arterial occlusions involving the superficial femoral artery. The procedure is successfully performed in all segments of the lower extremity with minimal morbidity or mortality. Rates of limb salvage and improvement in claudication are similar to those achieved by open surgical bypass, while modest reductions in limb salvage and primary patency are experienced in limbs with femorotibial occlusions.

Effect of renal insufficiency on outcome following infrarenal aortic surgery

BACKGROUND This study reviewed the effect of preoperative renal insufficiency on outcome following elective infrarenal aortic surgery. METHODS The charts of 210 consecutive patients undergoing aortic surgery (occlusive disease, 15%; aneurysmal disease, 78%; or combined disease, 7%) from 1990 to 1995 were categorized into three groups based on preoperative creatinine ([Cr] group 1 Cr < 1.5, n = 171; group 2 Cr 1.5 to 1.7, n = 22; and group 3 Cr > or = 1.8, n = 17) and calculated creatinine clearance ([CrCl] CrCl > 45 mL/min, n = 162 versus CrCl < 45 mL/min, n = 48). Patients with renal artery stenosis or those who required suprarenal cross clamping or emergency procedures were excluded. Differences in postoperative intensive care unit (ICU) stay, ventilator days, dialysis dependence, morbidity, and, mortality were compared. RESULTS Patients in groups 2 and 3 had an increased incidence of postoperative dialysis dependence (group 2 9%, group 3 8%) when compared with patients in group 1 (group 1: 0%, P < 0.05). Patients in the CrCl > 45 group had a lower mortality rate when compared with patients with a CrCl < 45 (CrCl > 45 0.6% versus CrCl < 45 8%, P <0.05) a lower incidence of dialysis (0% versus 7%, P <0.05), and a lower incidence of postoperative serum creatinine elevation from baseline (CrCl > 45 8% versus CrCl < 45 18%, P <0.05). There was no significant difference in morbidity, ICU stay, or ventilator days between the groups. Upon regression analysis, preoperative CrCl but not Cr was predictive of postoperative mortality (P <0.05). Serum Cr was more predictive than CrCl of impaired renal function postoperatively. CONCLUSIONS Preoperative CrCl is more accurate than Cr as a predictor of postoperative mortality. Patients with preoperative CrCl < 45 mL/minute who undergo elective aortic surgery have a significant increase in postoperative cardiac-related mortality and dialysis.

Selective stenting in subintimal angioplasty: Analysis of primary stent outcomes

OBJECTIVE Subintimal angioplasty (SIA) is being increasingly utilized to treat chronic arterial occlusions. The role of stents in SIA is currently unknown. We performed a retrospective review of selective stent use in SIA to assess outcomes and factors affecting these results. METHODS A retrospective review of patient information--including demographics, indications, procedures, noninvasive studies, and post-procedural events--was performed on our database for patients undergoing SIA in the superficial femoral and popliteal arteries. Outcomes were calculated only on technically successful SIAs using Kaplan-Meier survival analysis. Continuous and non-continuous data were compared using the Student t test and the z test, respectively. Survival curves were compared using log-rank testing for univariate analysis and Cox hazard-regression analysis for multivariate analysis. RESULTS Three-hundred-sixty-eight patients (382 limbs) underwent femoral and/or popliteal SIA for critical limb ischemia or disabling claudication from December 1, 2002 through July 31, 2006. Eighty-four limbs (22%) had a stent placed, while 298 (78%) did not receive a stent. Mean follow-up was 11.7 months (range, 0-45 months). One-year primary and secondary patency for stent vs no-stent group was 50% vs 45% (P = .73) and 70% vs 78% (P = .47), respectively. One-year limb salvage rate for the stent vs no-stent group was 85% vs 90% (P = .61). At 2 years, patients receiving a stent are more likely to undergo open bypass than those without a stent (P = .06). Eighty-three patients underwent 84 SIA with stent placement. The mean number of stents for each case was 1.4 +/- 0.7. Univariate analysis revealed that previous ipsilateral bypass surgery significantly decreased 1-year patency: 35% vs 56% (P = .05). SIA performed for disabling claudication had a trend toward improved 1-year patency 58% vs 39% for critical limb ischemia (P = .09). A stent diameter > or =7 mm displayed a trend toward better patency 53% vs 37% for diameter < or =6 mm (P = .08). None of these factors proved significant with multivariate analysis. CONCLUSION Selective stents placed for suboptimal results after subintimal angioplasty produce similar patency rates to primary SIA without stents. Patients receiving stents with prior lower extremity bypass surgery will have worse outcomes than those without. Use of a stent diameter < or =6 mm and indication of critical limb ischemia will likely produce worse results. It appears that other stent variables (location, number, length, and overlap) do not alter patency. Finally, selective stent use after SIA provides excellent limb salvage.

Management of large high-flow arteriovenous malformations of the shoulder and upper extremity with transcatheter embolotherapy.

PURPOSE To evaluate the efficacy of transcatheter embolization of arteriovenous malformations (AVMs) of the shoulder and upper extremity. PATIENTS AND METHODS Four men with large AVMs of the shoulder and upper extremity were treated with transcatheter arterial embolization. Symptoms included high cardiac output, pain, paresthesias, and disfigurement. Each patient underwent multiple sessions of embolotherapy. RESULTS In two patients there was no decrease in cardiac output. In three patients, no permanent decrease in AVM size or resolution of pain was achieved. Two patients experienced postembolization skin necrosis, and one experienced permanent radial neuropathy. CONCLUSIONS Large, high-flow AVMs in the shoulder and upper extremity may be relatively refractory to intravascular treatment because of the diffuse involvement of the soft tissues by the AVM and the lack of a well-defined nidus. Transcatheter embolotherapy in these lesions should be reserved for patients undergoing resection to help decrease intraoperative bleeding.