Intraoperative imaging techniques in infrainguinal arterial bypass grafting: completion angiography versus vascular endoscopy

Influence of Angioscopic Vein Graft Preparation on Development of Neointimal Hyperplasia in an Organ Culture Model of Human Saphenous Vein

Purpose:

Angioscopy for in situ vein graft preparation has been criticized on the basis that the trauma of instrumentation may predispose to accelerated intimal hyperplasia, jeopardizing patency rates following infrainguinal revascularization. The aim of this study was to assess the effects of angioscopic preparation on endothelial integrity and smooth muscle cell (SMC) behavior in an established organ culture model of human saphenous vein (HSV).

Methods:

HSV was harvested from 12 patients during bypass surgery before and after angioscopic preparation. Endothelial integrity was evaluated by immunohistochemical staining with JC-70 and scanning electron microscopy (SEM); remaining segments of pre-and postangioscopy vein were maintained in culture for 14 days in medium supplemented with 30% fetal calf serum. Viability was confirmed by measurement of tissue adenosine triphosphate on day 14 and thickness of the neointima was measured by computerized image analysis of histologic sections. Monoclonal antibodies to proliferating cell nuclear antigen (PCNA) were used as an immunohistochemical marker for proliferating SMCs.

Results:

There was a significant reduction in the percentage staining by JC-70 (71.3% versus 20.4%) in pre- versus postangioscopy vein (p = 0.002 by Wilcoxon's rank test; n = 12). This was supported by SEM images. Despite this, there were no significant differences between the pre- and postangioscopy HSVs after 14 days of culture with respect to neointimal thickness (61 versus 56 μm) and staining with PCNA (4.80 versus 4.08 nuclei per 10 (μm), all according to Wilcoxon's rank test.

Conclusions:

Angioscopic vein graft preparation is associated with endothelial cell loss but does not induce additional neointimal hyperplasia in HSV in vitro. These results suggest that angioscopic manipulation does not alter SMC behavior.

Benefits of Intraoperative Digital Subtraction Angiography in Primary Arteriovenous Fistula Creation

Digital subtraction angiography (DSA) is an ideal procedure for improving vascular surgery results, not yet in use for arteriovenous fistula (AVF) creation. In a prospective study, the practicability and benefits of intraoperative completion DSA (CDSA) for this purpose were investigated. When the arteriovenous anastomosis was completed and clinically judged as running, DSA via percutaneous or open-site puncture was conducted. Findings and consequences were prospectively documented. From July 2005 to September 2006 a primary AVF was created in 54 patients. Fifty of these could be included in the study (68, 39–91 yrs). In 44 a forearm fistula, and in six patients an elbow fistula was newly created. In two cases we were unable to insert a cannula into the A. brachialis (study escape). In the remaining 48 cases, CDSA visualized afferent artery, anastomosis and draining vein. No complications occurred associated with CDSA; 3.5, 2–12 ml, contrast agent were required per patient. In 13 cases, CDSA revealed problems with the AVF that could be corrected immediately: the vein was freed from restraining soft tissue (n=4), a stealing venous branch was ligated (n=6), transluminal thrombectomy was conducted (n=1) or anastomosis was newly created (n=3). AVF could be successfully created proven by ongoing dialysis in 30 cases, and in eight cases as demonstrated by clinical and sonographic evaluations, resulting in a primary 1-yr patency rate of 79.2%. CDSA in AVF surgery is practicable and reveals conditions that can be corrected immediately, thus improving surgical outcome. Long since standard in other areas of vascular surgery, CDSA should become a routine procedure in AVF creation.

Intraoperative angioscopy may improve the outcome of in situ saphenous vein bypass grafting: a prospective study

OBJECTIVE

To find out whether intraoperative angioscopic assistance has any effect on graft outcome in patients with critical leg ischemia.

MATERIAL AND METHODS

One hundred one patients requiring a below-knee bypass were assigned to undergo in situ saphenous vein bypass with or without intraoperative angioscopic assistance; otherwise treated similarly including preoperative duplex vein mapping, intraoperative graft flow measurements, and angiography. Data on operative details, morbidity, hospital stay, and graft patency were collected prospectively and compared. All patients were followed up for 12 months.

RESULTS

The group that underwent angioscopy (A) and the control group (B) were similar in all respects, except for the number of patients enrolled in the groups (32 and 69, respectively). Angioscopy revealed incompletely destructed valves in 34 patients (range, 0 to 5; mean 1), undiagnosed vein branches in 111 patients (mean 4.3), and partly occluding thrombus in 5 patients. The number of postoperative arteriovenous fistulas with signs of failing graft and a need for angiographic or surgical reintervention were significantly higher in group B (P <.0001). The 1-year primary patency rate was significantly better in group A (P <.01), but the primary assisted and secondary patency rates did not differ between the groups.

CONCLUSIONS

Angioscopic assistance has an impact on primary graft patency, minimizes the risk for graft failure and thus reduces the need for reintervention by allowing identification of persistent saphenous vein branches, incomplete valve destruction, and partly occluding graft thrombus without adding extra operative time.

Diagnostic and interventional angioscopy

As an imaging modality, angioscopy provides a simple method for the careful evaluation and treatment of the lumen of native vessels and bypass grafts. When used as a diagnostic study, angioscopy can provide more accurate information regarding the flow surface than conventional tests, such as angiography or duplex imaging. It can significantly enhance the ability of the surgeon to detect flow surface problems. With the recent advance in endovascular tools, angioscopically guided luminal intervention has become an increasingly useful approach to many vascular problems. More precise treatment of endoluminal abnormalities and a reduction in incision length and soft-tissue dissection can result in decreased patient morbidity and extended patient benefit.

Influence of angioscopic vein graft preparation on development of neointimal hyperplasia in an organ culture model of human saphenous vein

PURPOSE

Angioscopy for in situ vein graft preparation has been criticized on the basis that the trauma of instrumentation may predispose to accelerated intimal hyperplasia, jeopardizing patency rates following infrainguinal revascularization. The aim of this study was to assess the effects of angioscopic preparation on endothelial integrity and smooth muscle cell (SMC) behavior in an established organ culture model of human saphenous vein (HSV).

METHODS

HSV was harvested from 12 patients during bypass surgery before and after angioscopic preparation. Endothelial integrity was evaluated by immunohistochemical staining with JC-70 and scanning electron microscopy (SEM); remaining segments of pre- and postangioscopy vein were maintained in culture for 14 days in medium supplemented with 30% fetal calf serum. Viability was confirmed by measurement of tissue adenosine triphosphate on day 14 and thickness of the neointima was measured by computerized image analysis of histologic sections. Monoclonal antibodies to proliferating cell nuclear antigen (PCNA) were used as an immunohistochemical marker for proliferating SMCs.

RESULTS

There was a significant reduction in the percentage staining by JC-70 (71.3% versus 20.4%) in pre- versus postangioscopy vein (p = 0.002 by Wilcoxon's rank test; n = 12). This was supported by SEM images. Despite this, there were no significant differences between the pre- and postangioscopy HSVs after 14 days of culture with respect to neointimal thickness (61 versus 56 microns) and staining with PCNA (4.80 versus 4.08 nuclei per 10 microns), all according to Wilcoxon's rank test.

CONCLUSIONS

Angioscopic vein graft preparation is associated with endothelial cell loss but does not induce additional neointimal hyperplasia in HSV in vitro. These results suggest that angioscopic manipulation does not alter SMC behavior.

Angioscopically-assisted in situ saphenous vein bypass for infrainguinal revascularisation

OBJECTIVES AND STUDY DESIGN

The diagnostic capability of angioscopy for endoluminal evaluation is established and its superiority over arteriography for completion studies has been confirmed. The therapeutic use of angioscopy in vein graft preparation is more controversial. The aim of this prospective study was to establish whether angioscopic vein preparation confers real benefits over existing techniques.

METHODS

Forty-seven patients were randomised to either full angioscopic (ANG) vein preparation (23 patients) or conventional (CON) in situ grafting (19 patients). All patients underwent completion studies with arteriography and angioscopy and postoperatively, entered a Duplex graft surveillance programme.

RESULTS

There was a significant difference in the incidence of wound morbidity: 26% in the ANG group as against 63% in the CON group (Fisher's exact test: p = 0.043), but no significant differences with respect to duration of operation, duration of vein graft preparation, length of hospital stay and both 30 day and 12 month secondary cumulative patencies (log rank test: p > 0.5). Completion angioscopy detected eight persistent valve cusps in six patients, all missed at arteriography, but failed to detect arteriovenous fistulae.

CONCLUSIONS

Angioscopic preparation reduces wound morbidity and complements arteriography for detecting intraoperative defects. A large, prospective, randomised trial is now warranted to fully evaluate the potential therapeutic role of angioscopy with respect to current vascular practice.

Have the results of infrainguinal bypass improved with the widespread utilisation of postoperative surveillance?

OBJECTIVES

The objectives of this study were to assess the impact of Duplex surveillance on the results of infrainguinal vein grafts. A review has been performed comparing the outcome of vein grafts undergoing Duplex surveillance plus prophylactic treatment of stenoses to that of vein grafts followed clinically.

DESIGN, PATIENTS, AND METHODS

Only studies providing information on occlusion rates were included. Mortality and limb salvage rates were also analysed but were not available from all studies.

RESULTS

2680 surveillance and 3969 non-surveillance vein grafts were analysed. There was no significant difference between the two groups with respect to presence of critical ischaemia (p=0.3) and level of distal anastomosis (p>0.5). Surveillance identified 493 stenoses in 469 (19%) grafts, 397 (16%) grafts were treated by surgery (248; 62%) and angioplasty (149; 38%). Ninety-eight (26%) grafts developed recurrent stenoses. Total number of deaths, total number of occluded grafts and number of occlusions after 30 days were significantly greater for the non-surveillance group (p<0.001; p<0.001; p<0.01). Perioperative occlusion rates were not significantly different (p=0.1). Few surveillance studies reported limb salvage rates (6 of 17). The numbers of amputations were not significantly different between the two groups (p>0.5).

CONCLUSIONS

The patency of infrainguinal vein grafts would appear to be improved as a result of surveillance. However, no improvement in limb salvage has been demonstrated.

Angioscopy in vascular surgery: the state of the art

Although angioscopy is considered by many vascular surgeons to be a valuable clinical tool, others view it as expensive and unnecessary. To better define the appropriate role for angioscopy in vascular surgery, a critical review of the recent literature was undertaken. Angioscopy allows more complete valvulotomies with fewer endothelial injuries when preparing autogenous veins to be used as arterial conduits, and results in more complete thromboembolectomy of native arteries and grafts. Angioscopy can replace completion arteriography in infrainguinal arterial reconstructions with an equivalent clinical outcome. Angioscopy may be useful in the assessment of carotid endarterectomy, femoral vein valve repair, and pulmonary embolectomy. It has been useful in various research applications. The rate of complications is less than 1%. Angioscopy is of benefit in preparing veins to be used as arterial conduits and in performing thromboembolectomy. In some circumstances it can replace intraoperative arteriography. Other applications await further validation. The risks of angioscopy are acceptably low.

Prospective study of the value of prebypass saphenous vein angioscopy

BACKGROUND

The patency of a saphenous vein graft is directly related to the quality of the vein harvested. Thus, appropriate evaluation of the vein before implanting it as a bypass graft may help identify those veins at high risk for early failure. Accordingly, we prospectively investigated whether prebypass angioscopic assessment of the saphenous vein could identify those vein grafts at particularly high risk of early failure.

PATIENTS AND METHODS

Thirty-two greater saphenous veins with a grossly normal appearance were evaluated angioscopically before their use as a bypass conduit. After modification of abnormal segments, all of the veins irrigated well and were used as bypass grafts.

RESULTS

Twenty-four patients were available for follow-up at 12 months. Seventeen (71%) had been prospectively classified as having angioscopically normal saphenous veins, while 7 were identified as having abnormal veins. The two groups did not differ significantly in demographics, cardiovascular risk factors, or indications for operative intervention. Twelve of the 17 (70%) normal veins were patent at 1 year; however, only 1 (14%) of the angioscopically abnormal vein grafts remained patent for 12 months (chi-square = 4.27; P = 0.039).

CONCLUSION

Angioscopic inspection of the saphenous vein, before insertion as a graft, allows for identification of unrecognized venous disease that portends early graft thrombosis. Exclusion of abnormal veins, based on an abnormal angioscopic appearance, may lead to improved results for lower-extremity revascularization procedures; this supports the value of vein-graft angioscopy.