Intraoperative angiography and endovascular ultrasound imaging.

Endovascular ultrasound imaging is a new technique that can be used to monitor intraoperatively the effects of balloon angioplasty or to inspect the quality of vascular reconstruction, such as endarterectomy or bypass surgery. The technique is based on high frequency ultrasonic imaging (30-40 MHz) using a rotating single element transducer mounted in an 8F catheter tip, providing 360 degrees cross-sectional real time images. The clinical application is based on the high correlation between the ultrasonic images and the histological characteristics of the corresponding vessel wall tissue and lumen geometry, as has been established in previous in vitro studies. Endovascular ultrasound assessment of percutaneous angioplasty procedures or intraoperative vascular reconstruction has become an adjunct to angiographic and/or angioscopic monitoring.

A new "closed" in situ vein bypass technique.

AIM: We have developed a new closed technique using a co-axial catheter embolisation system for intraoperative coil embolisation of the side branches of in situ vein bypass grafts in order to avoid long skin incisions. TECHNIQUE: After completion of the proximal anastomosis, disruption of the valves and completion of the distal anastomosis, the catheter is introduced via a proximal side branch of the greater saphenous vein. Under fluoroscopic control the side branches are identified, selectively catheterised and an embolisation coil is positioned in each side branch. PATIENTS: In 14 patients (eight men, six women), 16 in situ bypasses were performed (12 below knee femoro-popliteal, four femoro-crural). RESULTS: Once mastered the embolisation procedure took less than 1 hour. In four cases persistent arteriovenous fistulae had to be treated in the postoperative period. Two major wound complications occurred and there were three early failures. One late failure occurred due to a rupture of the venous bypass 6 weeks postoperatively. The remaining 12 bypasses are patent, with a median follow-up of 16 (3-26) months. CONCLUSION: These preliminary results suggest that the "closed" technique is feasible and that long term occlusion of AV-fistulae can be achieved without ligation via incisions.

Dobutamine-atropine stress echocardiography for assessment of perioperative and late cardiac risk in patients undergoing major vascular surgery.

OBJECTIVE: To determine the value of dobutamine-atropine stress echocardiography and clinical variables to predict perioperative and late cardiac events in patients scheduled for elective major non-cardiac vascular surgery. DESIGN: Blinded prospective study. PATIENTS: Patients (n = 187 mean age 69 yrs). MEASUREMENTS: Dobutamine-atropine stress test was performed preoperatively. Results were not used for clinical management. The clinical risk profile was evaluated by Detsky's score. RESULTS: Technically adequate images were obtained in 185/187 patients, one major complication occurred (ventricular fibrillation) and four tests were prematurely stopped due to side effects. Data from 181 patients were analysed. The stress test was positive (new or worsened wall motion abnormality) in 56/181 patients. Perioperative cardiac events were: five fatal myocardial infarctions, three non-fatal myocardial infarctions, nine unstable angina pectoris and one pulmonary edema. All patients with a cardiac event had a positive stress test (18/56). No event occurred in patients with a negative stress test. By multivariate analysis only a new wall motion abnormality during the stress test (odds ratio 45.0, 6-369) was a significant predictor of cardiac events. Patients (n = 154) were followed after operation for 16 +/- 9 months. Twenty-four cardiac events occurred in 21 patients: six fatal myocardial infarctions, three non-fatal myocardial infarctions, six unstable angina pectoris, three ventricular arrhythmias and six congestive heart failures. The stress echo was positive in 19/21 patients with late cardiac events. The cardiac events correlated by multivariate analysis with a history of myocardial infarction (odds ratio 9.6, 1.9-47.7) and new wall motion abnormalities (odds ratio 6.2, 1.5-25.1). CONCLUSION: Dobutamine-atropine stress echocardiography is a relatively safe and useful test to identify patients at risk of perioperative and late postoperative cardiac events.

Femoro-popliteal vein bypass grafts studied by intravascular ultrasound.

The usefulness of intra-operative intravascular ultrasound (30 MHz) was evaluated in three patients who underwent a femoropopliteal vein bypass. Intravascular echography analysis of the surgical procedure revealed a normal uneventful result in one patient. In two other patients obstructions in the vein grafts were identified either caused by internal obstruction or external compression. Angiography in these two patients provided equivocal data. We conclude that intravascular ultrasound imaging may be a useful adjunct to angiography and may offer important clinical data to facilitate the surgeons in analysing the results of the interventional procedures.

Femorodistal venous bypass evaluated with intravascular ultrasound.

OBJECTIVE: To evaluate the feasibility of intravascular ultrasound imaging during femorodistal venous bypass procedures to assess qualitative and quantitative parameters of the greater saphenous vein and to detect potential causes for (re)stenosis and/or occlusion. METHODS: Intravascular ultrasound data obtained from 15 patients were reviewed and compared with angiographic data. RESULTS: Intravascular ultrasound enabled differentiation between normal and thickened vein wall. Venous side-branches could be located. Intact valves could be differentiated from valves disrupted by valve cutting. Patent anastomoses could be distinguished from anastomoses with some degree of obstruction. Intravascular ultrasound imaging of the inflow and outflow tracts revealed obstructive lesions, not evidenced angiographically. Quantitative analysis revealed that the median normal vein wall thickness (tunica intima and tunica media) was 0.25 mm (range 0.17-0.40 mm). The distinct vein wall thickening encountered in three patients measured 0.82, 0.95 and 1.06 mm, respectively, and was associated with narrowing in two patients. In five of 15 patients intravascular ultrasound findings altered surgical management. CONCLUSION: Intravascular ultrasound is able to assess qualitative and quantitative parameters of the venous bypass and has the potential to influence surgical management based on morphologic and quantitative data.

A new "closed" in situ vein bypass technique results in a reduced wound complication rate.

OBJECTIVES: This prospective randomised multicentre trial was conducted to test whether a new "closed" technique for in situ vein bypass would result in a lower frequency of wound complications, without negative effects on patency rates and without an intolerable increase in residual arteriovenous fistulae compared to the conventional "open" technique. METHODS: We have developed a new "closed" technique using a co-axial catheter embolisation system for intra-operative coil embolisation of side branches, in order to avoid long incisions. PATIENTS: In four centres and 95 patients, 97 in situ bypasses were performed: 47 "closed" and 50 "open". Randomisation was stratified for below knee femoropopliteal bypasses (60) and femorocrural bypasses (37). Indications were disabling intermittent claudication (29), restpain (26) or ulcers and/or necrosis (42). RESULTS: Postoperative mortality was 2% (one in the "closed", one in the "open" group). A total number of 16 (34%) wound complications (grade 1, 2 and 3) occurred in the closed group compared to 36 (72%) in the open group (p < 0.05). Deep wound complications (grade 2) occurred in six patients (13%) of the "closed" group, compared to 15 (30%) in the "open" group. In both groups, three patients (6%) developed deep wound complications including the bypass area (grade 3). In the "closed" group, 20 patients needed additional treatment for arteriovenous fistulae, compared to four in the "open" group. One-year patency rates did not show a statistically significant difference: primary patency rates were 65% and 61% and secondary patency rates were 86% and 76% respectively for the "closed" and "open" group. CONCLUSION: These results indicate that a "closed" technique reduces wound complication rate, without negative effects on the short term patency rates. The "closed" technique results in an increased number of postoperative treatments for residual arteriovenous fistulae.

Ultrasound-guided percutaneous coil embolization of incompetent perforating veins: not effective for treatment of venous ulcers and recurrent varicosities.

PURPOSE: To investigate the feasibility of ultrasound-guided percutaneous coil embolization of incompetent perforating veins as minimally invasive treatment for venous ulcers and recurrent varicosities in the lower leg. This could be an alternative to surgical ligation of perforating veins. MATERIALS AND METHODS: In 15 patients (six women, nine men; mean age, 50 years), 18 incompetent perforating veins in the lower leg were treated by ultrasound-guided percutaneous placement of embolization coils. RESULTS: Successful vein occlusion with one or more coils was achieved in 12 of the 18 veins (technical success rate, 67%). Clinical symptoms improved in only three of the 15 patients (clinical success rate, 20%). During follow-up (2-12 months), recanalization of coil embolized veins occurred in nine of the 12 initially occluded veins. CONCLUSION: Percutaneous ultrasound-guided coil embolization does not appear to be as effective as subfascial endoscopic perforator surgery in the treatment of incompetent perforator veins.

Endovascular stent-grafts for aneurysms of the femoral and popliteal arteries.

Our objective was to investigate the preliminary use of endovascular stent-grafts for the treatment of femoropopliteal artery aneurysm. Ten patients with an aneurysm of the femoropopliteal artery referred for endovascular treatment were investigated. The series consisted of patients with a true aneurysm of the superficial femoral artery (n = 2); a true aneurysm of the popliteal artery (n = 4); an aneurysmal dilatation of a Biograft bypass (n = 2); a false aneurysm of the superficial femoral aneurysm (n = 1); and a false aneurysm of a composite bypass (n = 1). In 8 of the 10 patients the stent-graft was composed of one or more Palmaz stents sutured to an ePTFE tube graft; in the other 2 patients a venous covering was used in combination with Palmaz stents. The procedure was guided by angiography and intravascular ultrasound. The results of our investigation showed that endovascular stent-grafting of aneurysms of the femoropopliteal artery is a feasible but experimental technique that should be restricted to a selected group of patients.

Intravascular ultrasound in endovascular stent-grafts for peripheral aneurysm: a clinical study.

PURPOSE: To evaluate the potential diagnostic information of intraprocedural intravascular ultrasound (IVUS) in patients undergoing endovascular stent-grafting for peripheral aneurysm. METHODS: IVUS was used in 17 patients preprocedurally to measure the diameter of the proximal and distal neck and the length of the aneurysm. Balloon and stent-graft sizes were selected based on these measurements. Following stent-graft deployment, angiography and IVUS were used to document stent apposition and the configuration and diameter of the stent-graft. RESULTS: Stent-graft insertion was considered successful in 8 patients based on angiography and IVUS images. In 9 others, both imaging modalities showed inadequate results, necessitating 12 additional procedures: balloon angioplasty for stent-graft stenosis (2) and inadequate stent-graft apposition (1); an additional stent-graft (4); an extra stent (1); thrombectomy (2); and conversion (2) for inadequate stent-graft position and a graft rupture. In these patients, intraprocedural IVUS was superiorto angiography in contributing vital information to aid in the selection of the additional interventions. CONCLUSIONS: During management of peripheral aneurysms with endovascular stent-grafts, IVUS monitoring was a useful adjunct when the initial procedure was unsatisfactory and/ or when intraprocedural angiographic studies were inconclusive.

Intravascular ultrasonography before and after intervention: in vivo comparison with angiography.

PURPOSE: To compare the additional capacity of intravascular ultrasonography versus angiography to assess morphologic features and lumen dimension, 37 patients undergoing vascular intervention of the common iliac or superficial femoral artery were studied. A total of 181 ultrasonic cross sections were analyzed (94 before and 87 after intervention). METHODS AND RESULTS: Before intervention intravascular ultrasonography distinguished normal cross sections (n = 17) from cross sections with a lesion (n = 77): soft (51%) versus hard (31%) lesions, and eccentric (75%) versus concentric (7%) lesions. After intervention intravascular ultrasonography documented dissection (43%), plaque rupture (10%), and internal elastic lamina rupture (8%). A good correlation between ultrasonography and angiography was found for the recognition of eccentric or concentric lesions and dissections. The degree of stenosis was assessed semiquantitatively by visual estimation of the degree of luminal narrowing from the angiograms and intravascular ultrasonic images and was categorized into four classes: (1) normal, (2) less than 50% stenosis, (3) 50% to 90% stenosis, and (4) greater than 90% stenosis. Intravascular ultrasonographic assessment of stenosis was in agreement with angiography in 78% of cases and showed more severe lesions in 22% before intervention. Similar data were observed after intervention, with 72% of results being in agreement and 28% of cases showing more severe lesions. The degree of stenosis was also quantitatively evaluated by computer-aided analysis of the intravascular ultrasonic images. The semiquantitative analysis by intravascular ultrasonography corresponded well with the quantitative analysis done by the computer-aided system. When both echography and angiography suggested that arteries were normal, quantitative intravascular ultrasonography identified lesions that occupied an average of 18% of the cross-sectional area of the vessel. CONCLUSIONS: This in vivo study shows that intravascular ultrasonography is capable of documenting detailed morphologic features. Semiquantitative ultrasonic data correlate closely with those of angiography, albeit stenoses were assessed as more severe on ultrasonography.

Dobutamine stress echocardiography for assessment of perioperative cardiac risk in patients undergoing major vascular surgery.

BACKGROUND: The purpose of this study was to determine the predictive value of dobutamine stress echocardiography for perioperative cardiac events in patients scheduled for elective major noncardiac vascular surgery. METHODS AND RESULTS: Patients (n = 136; mean age, 68 years) unable to exercise underwent a dobutamine stress test before surgery (incremental dobutamine infusion [10-40 micrograms.kg-1.min-1] continued with atropine [0.25-1 mg i.v.] if necessary to achieve 85% of the age-predicted maximal heart rate without symptoms or signs of ischemia). The clinical risk profile was evaluated by Detsky's modification of Goldman's risk factor analysis. Echocardiographic images were evaluated by two observers blinded to the clinical data of the patients, and results of the test were not used for clinical decision making. Technically adequate images were obtained in 134 of 136 patients, one major complication occurred (ventricular fibrillation), and three tests were discontinued prematurely because of side effects. Finally, data from 131 patients were analyzed with univariate and multivariate methods. The dobutamine stress test was positive (new or worsened wall motion abnormality) in 35 of 131 patients. In the postoperative period, five patients died of myocardial infarction, nine patients had unstable angina, and one patient developed pulmonary edema. All patients with cardiac complications (15 patients) had a positive dobutamine stress test. No cardiac events occurred in patients with negative tests. Five patients with a technically inadequate or prematurely stopped test were operated on without complications. By multivariate analysis (logistic regression), only age > 70 years and new wall motion abnormalities during the dobutamine test were significant predictors of perioperative cardiac events. CONCLUSIONS: Dobutamine stress echocardiography is a feasible, safe, and useful method for identifying patients at high or low risk of perioperative cardiac events. The test yields additional information, beyond that provided by clinical variables, in patients who are scheduled for major noncardiac vascular surgery.