F. Noel Parent

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.

Long-term follow-up for recurrent stenosis: A prospective randomized study of expanded polytetrafluoroethylene patch angioplasty versus primary closure after carotid endarterectomy

PURPOSE To determine the effect of primary closure (PC) versus expanded polytetrafluoroethylene patch graft angioplasty (PGA) on the incidence of recurrent stenosis (> 50% lumen diameter narrowing) after carotid endarterectomy (CEA), 87 patients undergoing 100 consecutive CEA were prospectively randomized into two groups. METHODS Forty-four patients underwent 51 PC, and 43 patients underwent 49 PGA. All patients were evaluated after operation by duplex scanning at 1.5, 12, 24, and 36 months. There were no significant differences in the demographic characteristics or operative indications for CEA between the two patient groups. Complete follow-up was achieved in 86% (75/87) of the patients during the 36-month surveillance period. RESULTS The perioperative permanent neurologic morbidity in the PC and PGA groups was noted to be 4% and 2%, respectively (PC = 2/51 vs PGA = 1/49, p = 0.58). Three additional reversible cerebral ischemic events occurred in the postoperative period (PC = 2/51 vs PGA = 1/49, p = 0.58). Other morbidity included immediate postoperative hemorrhage requiring reexploration (1/51) in the PC group and an infected expanded polytetrafluoroethylene patch requiring removal and replacement with autogenous vein (1/49). Long-term follow-up detected a single patient with significant bilateral restenoses of his primarily closed carotid arteries. None of the patients in the PGA group had restenoses (PC = 2/51 vs 0/49, p = 0.50). In addition, no postoperative dilation of the common or internal carotid arteries or perioperative death was observed. CONCLUSIONS In patients undergoing CEA, these data demonstrate no significant difference in the perioperative morbidity or mortality between PC and PGA. Use of the patch did not engender patients to patch rupture or aneurysmal degeneration as previously described with vein patch angioplasty procedures. This series supports effective use of either technique to achieve minimal rates of restenosis.

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.

Endoleak after endovascular aneurysm repair: Duplex ultrasound imaging is better than computed tomography at determining the need for intervention

OBJECTIVE Color duplex ultrasound (CDU) imaging is a noninvasive alternative to computed tomography (CT) for the detection of endoleak. This study compared CT and CDU imaging in the detection of endoleaks requiring intervention after endovascular aneurysm repair (EVAR). METHODS All EVARs performed at our institution from 1996 to 2007 were retrospectively reviewed. CDU and CT scans < or =3 months were paired and the presence of an endoleak and its type were recorded. Clinical follow-up was reviewed and interventions for endoleak were recorded. Interventions were performed for type I, for type II with sac enlargement, and for type III endoleaks. The first analysis of clinical test outcomes used the findings of CT scan as a gold standard and the second used the findings at time of intervention as a gold standard. RESULTS During the time period reviewed, 496 patients underwent EVAR, and 236 of these had CDU and CT follow-up studies paired < or =3 months of each other. Mean follow-up was 17 months (range, <1-111 months). We reviewed 944 studies or 472 pairs. Eighteen patients (7.6%) required intervention for 19 endoleaks: six type I, 11 type II, and two type III. Early endoleak (< or =1 month) requiring reintervention was detected in 1 vs late endoleak (mean, 28 months; range, 0.6-88 months) in 18. All type I and III endoleaks were treated with endovascular cuff or limb extension placement. Three type II endoleaks were treated with open ligation, and coil or glue embolization was used in eight. CDU imaging detected endoleaks requiring intervention in 89% of cases, whereas CT detected endoleak in 58% (P < .05). The ability to correctly identify the type of endoleak as confirmed at time of intervention was 74% with CDU imaging vs 42% by CT (P < .05). CDU, for the detection of endoleak requiring intervention, had a sensitivity of 90%, specificity of 81%, negative predictive value (NPV) of 99%, and positive predictive value (PPV) of 16%, while CT had a sensitivity of 58%, specificity of 87%, NPV of 98%, and PPV of 15%. CONCLUSIONS CDU imaging has a high sensitivity in detecting endoleaks requiring intervention, is better at identifying the type of endoleak, and is an excellent test for graft surveillance after endovascular aneurysm repair. Compared with CT scan, CDU imaging in our experience is the preferred test on which to base an intervention for endoleak.

Value of radiographs and bone scans in determining the need for therapy in diabetic patients with foot ulcers

Thirty-two diabetic patients with foot ulcers were evaluated. Twenty-five patients had foot radiographs, technetium-99m bone scans, and wound and bone cultures; the remaining seven patients had all the studies except bone scanning. Bone changes compatible with osteitis were present on 15 of 32 foot radiographs (47 percent) and on 16 of 25 bone scans (64 percent). Bacterial growth was present in 27 of 32 wounds (84 percent) and 23 of 32 bone cultures (72 percent). Twelve of 23 patients (52 percent) with positive bone cultures had evidence of bone destruction and periosteal reaction on radiographs. The remaining 11 of 23 patients (48 percent) without radiographic signs of osteitis had bacterial growth from their bone cultures. Bone scans were positive in 12 of 18 patients (67 percent) with positive bone cultures and negative in 6 of 18 positive bone cultures (33 percent). We conclude that neither foot radiographs, technetium-99m bone scans, nor wound cultures should be used as the sole criterion for determining the use of antibiotic therapy or amputation in diabetic patients with foot ulcers.

The use of composite grafts in femorocrural bypasses performed for limb salvage: A review of 108 consecutive cases and comparison with 57 in situ saphenous vein bypasses

We retrospectively reviewed the results of 108 consecutive femorocrural bypasses performed with prosthetic/autogenous composite graft material and compared these with the results of 57 crural bypasses using greater saphenous vein by the in situ technique. Indication for operation in all cases was the salvage of an otherwise imminently threatened limb. Polytetrafluoroethylene-composite grafts (n = 87) and human umbilical vein-composite grafts (n = 21) were placed only in patients lacking suitable autogenous material for in-line reconstruction. Patient groups were similar with respect to mean age, prevalence of arterial disease risk factors, quality of the distal runoff, and location of the distal anastomosis. Cumulative patency rates at 1 year by life-table analysis were 81.9%, 34.6%, and 12.1% for the in situ, polytetrafluoroethylene-composite and human umbilical vein-composite groups, respectively. At 2 years these were 63.9%, 29.9%, and 6.0%, respectively (p less than 0.025). Cumulative limb salvage at 1 year was 70.6%, 62.3%, and 32.7%, respectively. Wound-related complications occurred in 52.4% of human umbilical vein-composite, 38.6% of in situ, and 18.3% of polytetrafluoroethylene-composite bypasses (p less than 0.05). On the basis of these results, we conclude that femorocrural bypass with polytetrafluoroethylene-composite graft is an acceptable form of distal reconstruction for limb salvage in patients lacking sufficient lengths of autogenous vein. We no longer use human umbilical vein for composite construction.

Subfascial perforator vein ablation: comparison of open versus endoscopic techniques.

Purpose: To compare the outcomes and complications of open (OSPS) versus endoscopic subfascial perforator surgery (SEPS) for treatment of chronic venous insufficiency. Methods: Data were retrospectively collected on 25 patients who underwent 27 SEPSs from February 1996 to August 1997 and from 22 patients who underwent 29 OSPSs between March 1978 and May 1993. Outcomes were evaluated for postoperative complications, ulcer healing, recurrence, and venous dysfunction scores on the last follow-up for the SEPS group and at 1-year follow-up for the OSPS group. Results: The 2 groups were similar in age, sex, history of previous venous surgery, healed or active ulcers, etiology, deep venous incompetency, pathophysiology, and venous refill times. Eighteen (90%) of 20 active ulcers in the SEPS group healed with recurrences in 5 (28%) limbs at 7.5 ± 5.4-month follow-up. All 19 ulcers in the OSPS group healed, with recurrences in 13 (68%) limbs at 35 ± 35-month follow-up. Clinical venous dysfunction scores showed significant improvement following SEPS (10.0 ± 3.6 to 5.4 ± 4.1, p < 0.001) and OSPS (10.0 ± 3.2 to 6.7 ± 3.6, p < 0.001) with no significant difference between groups. Both groups also had significant improvement in anatomical and disability scores. There was no postoperative mortality in either group. The OSPS group had significantly more wound complications (45%) than the SEPS group (7%) (p < 0.005). The hospital stay and readmission rate for wound problems were also higher in the OSPS group. Conclusions: The early outcome showed equal improvement in clinical venous dysfunction scores in the 2 groups, but with significantly fewer complications in the SEPS group. Although the long-term durability of the endoscopic approach has not been determined, the short-term results would favor SEPS for treatment of severe venous insufficiency when perforator incompetence is a significant component.

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 Foundations 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 groups 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.

A comparison of surgery for neurogenic thoracic outlet syndrome between laborers and nonlaborers

OBJECTIVE To determine factors of outcome following surgical intervention for neurologic thoracic outlet syndrome (NTOS). METHODS In a retrospective study of patients surgically treated for NTOS, outcome was evaluated by postoperative symptoms and the ability of patients to return to work. RESULTS Good, fair, and poor results were obtained in 26 (48%), 21 (39%), and 7 (13%) patients, respectively. The best predictor of a good outcome was occupation. Nonlaborers were more likely to have good outcome (21 of 32, 66%) when compared with laborers (5 of 22, 23%; P = 0.0025). Only 6 of 20 (30%) laborers were able to return to their original occupation compared with 17 of 26 (65%) nonlaborers (P = 0.036). CONCLUSIONS Laborers with NTOS are less likely to have a good result from surgical intervention, are unlikely to return to their original occupation, and may require retraining for a non-labor-intensive occupation if they cannot return to their original work.

Duplex Scanning for the Intraoperative Assessment of Infrainguinal Arterial Reconstruction: A Useful Tool?

Duplex scan, arteriography, and graft flow rates were used intraoperatively to assess 56 infrainguinal arterial reconstructions for technical error. Intraoperative duplex scan identified a technical defect or low graft flow velocity in 22 of 56 (39%) grafts. Eleven of the defects were judged to be clinically significant and were corrected. Four of these defects were missed by the completion arteriogram. One technical defect identified by completion arteriography was missed by duplex scan. Fifty percent (5/10) of grafts with an abnormal intraoperative duplex scan which were not corrected occluded within 30 days. Graft flow rates measured by the electromagnetic flowmeter were neither predictive of technical defect nor early graft outcome. Although the sensitivity of arteriography and duplex scan (88% sensitivity for both) were both high for predicting early graft occlusion, the combination of duplex scan and completion arteriography was significantly more accurate (p<.0001) in predicting early graft outcome than either study alone. Duplex scan identified significant graft defects which were not detected by completion arteriography or graft flow rate measurement. The duplex scan also provided hemodynamic information which was predictive of early graft outcome. The duplex scan can be an important adjunct to completion arteriography for the intraoperative assessment of infrainguinal arterial reconstruction.