Prospective study of the value of prebypass saphenous vein angioscopy

Relationship Between Preoperative Duplex Vein Mapping and Intraoperative Longitudinal Impedance in Infrainguinal Vein Grafts

The importance of favorable vein size, resistance, and impedance for the sustained success of infrainguinal vein grafting procedures has repeatedly been demonstrated. Estimating these properties preoperatively, however, has been problematic. Ultrasonic vein mapping is a reliable technique for measuring vein diameters at venous pressures, but it is unknown whether these data accurately assess the resistive potential of the conduit in the arterial circulation. The purpose of this study was to compare vein diameter measured preoperatively with vein graft longitudinal impedance measured intraoperatively.

Patients who had undergone both preoperative vein mapping and intraoperative impedance studies at the time of infrainguinal bypass were included (December 1995-April 1999). Vein mapping was performed using B-mode ultrasound with a 10 MHz probe. The dimensions of the specific vein segment used for reconstruction were tabulated and its mean diameter (D̄) was calculated. At the time of operation, following reconstruction, transgraft blood pressure gradient (δP) and blood flow (Q) waveforms were recorded by using digital data acquisition. Longitudinal impedance (ZL) was calculated as δP/Q at each harmonic following Fourier transformation and the area under the curve from 0 to 4 Hz designated as ∫ZL.

Twenty-three bypasses in 22 patients were studied (D̄ = 3.5 ±0.2 mm, range 1.6-5.5 mm; ∫ZL= 37 ±4 x 103 dyne cm-5, range 13-95 X 103 dyne cm-5). D̄ significantly correlated with ∫ZL (slope = -0.454, p < 0.05), albeit with a fairly low correlation coefficient ( r2 = 0.23). D̄ > 3.6 mm was predictive of graft patency at 12 months (D̄ > 3.6 mm 100% vs D̄ < 3.6 mm 57 ±20%; p = 0.02).

Larger veins identified by preoperative mapping have, in general, more favorable intraoperative resistive characteristics as defined by a lower JZL. However, some veins thought to have small diameters (< 3.6 mm) may still demonstrate sufficiently low ∫ZL when grafted to remain patent.

Preliminary Report of a New Approach to Sparing the Greater Saphenous Vein for Grafting: Valvuloplasty Combined with Axial Transposition of a Competent Tributary Vein

Purpose:

To compare a new vessel-sparing technique combining valvuloplasty with axial transposition of a competent tributary vein versus single valvuloplasty for the treatment of greater saphenous vein (GSV) incompetence.

Methods:

In 55 patients with GSV incompetence, 29 of 57 limbs were treated by angioscopic valvuloplasty of the subterminal valve alone, whereas the remaining 28 limbs underwent angioscopic valvuloplasty combined with axial transposition of a competent tributary vein identified preoperatively by duplex scanning. After angioscopic valvuloplasty in the latter group, the competent tributary vein was exposed and cut 1.5 cm distal to its insertion point on the GSV. The transected vein was anastomosed end to side to the GSV, which was ligated between the tributary insertion site and the anastomosis. Changes in venous hemodynamics, including venous filling index (VFI), ejection fraction (EF), and residual volume fraction (RVF), were analyzed by use of air plethysmography.

Results:

In the 1-year follow-up, no venous thrombosis was detected in either group. In the valvuloplasty-only group, 22 (75.9%) limbs exhibited reflux in the proximal GSV; recurrent varicose veins were detected in 5 (17.2%) limbs. In contrast, only 2 (7.1%) limbs showed reflux in the valvuloplasty + transposition group. There were no significant differences in EF and RVF between the groups before or after the operation, although a significant difference was seen in VFI at 1 year (p = 0.005, Wilcoxon rank sum test).

Conclusions:

Valvuloplasty combined with tributary vein transposition gives a better result than valvuloplasty alone at 1 year. This new treatment option may be useful for both reducing the rate of varicose veins and sparing the GSV for grafting.

Great saphenous vein sparing surgery by angioscopic valvuloplasty combined with axial transposition of a competent tributary vein--5-year follow-up

OBJECTIVE

To evaluate the efficacy and haemodynamic effects of great saphenous vein (GSV) sparing surgery--valvuloplasty combined with axial transposition of a competent tributary vein (A-VACT).

MATERIALS AND METHODS

Eighty-five limbs in 74 patients with isolated GSV incompetence were selected for GSV sparing surgery. After angiographic valvuloplasty, the competent tributary vein was exposed and cut 1.5 cm distal to its insertion point on the GSV. The transected vein was anastomosed end-to-side to the GSV, which was ligated between the tributary insertion site and the anastomosis. Venous valve competence were screened by serial postoperative duplex examination, and venous haemodynamic changes were analyzed using venous filling index (VFI) measured by air plethysmograph pre- and postoperatively. The follow-up period was 5-years.

RESULTS

Sixty-seven patients were included in whom 76 limbs were treated. There was a statistically significant reduction in the vein diameter at the SFJ after 5-years (0.83 S.D. 0.29 cm to 0.46 S.D. 0.12 cm, p=0.0002, Wilcoxon). Similarly, significant reduction was found in the GSV at the 5-year follow-up point (0.63 S.D. 0.19 cm to 0.39 S.D. 0.11 cm, p<0.0001, Wilcoxon). On the other hand, there was significant increase in the diameter of the competent tributary vein postoperatively (0.22 S.D. 0.13 cm to 0.31 S.D. 0.12 cm, p<0.0001, Wilcoxon). Duplex scanning demonstrated reflux at the SFJ in 12 limbs (16%). Similarly, in the GSV, venous reflux was found in 13 limbs (17%). Reflux in the transposed tributary vein was found in 20 limbs (26%). But only 7 limbs (9%) had minor varicose veins' recurrence. VFI remained normal during the follow-up examination. The preoperative VFI confirmed the presence of venous reflux, but there were significant improvement in the VFI values at all postoperative examinations.

CONCLUSIONS

A-VACT procedure improves venous function, resolves varicose veins at 5-years follow-up as well as preserving the GSV for future grafting.

Alternative greater saphenous vein-sparing surgery: valvuloplasty combined with axial transposition of a competent tributary vein for the treatment of primary valvular incompetence---18-month follow-up

BACKGROUND

The greater saphenous vein (GSV) is one of the best grafts for vascular reconstruction, and a variety of sparing methods in patients with primary varicose veins have been performed. Of these, valvuloplasty of the subterminal valve is useful, but reflux in the proximal GSV via a competent tributary vein still remains. To minimize the subsequent reflux, we propose a new method, "valvuloplasty combined with axial transposition of a competent tributary vein" for the treatment of GSV incompetence.

OBJECTIVE

To compare this new method with single valvuloplasty.

METHODS

Seventy-eight limbs in 65 patients with GSV incompetence were included. Of these limbs, 38 underwent angioscopic valvuloplasty of the subterminal valve alone (V group). The remaining 40 were treated by angioscopic valvuloplasty combined with axial transposition of a competent tributary vein (V + T group). A competent tributary vein was identified by duplex scan in the thigh before surgery. After angioscopic valvuloplasty had been done, a competent tributary vein was exposed, and was cut 1.5 cm distal to its insertion. The distal cut end of the vein was then transposed to the GSV and end-to-side anastomosis was performed using 8-0 nylon under magnification. The incompetent GSV was ligated between the insertion and the anastomosed region. Venous hemodynamic changes were analyzed using air plethysmography (APG). Values obtained by9 APG included venous volume (VV), venous filling index (VFI), ejection fraction (EF), and residual venous function (RVF). The follow-up period was 18 months. Intergroup differences were analyzed with the Wilcoxon ranked sum test for nonparametric distribution.

RESULTS

There were no statistical differences in age, gender, or clinical presentation between the two groups. In the V group, 27 limbs had reflux in the proximal GSV (67.4%). On the other hand, only 6 limbs (13.3%) showed minor reflux in the V + T group. A significant difference was seen in VFI at 1 year, and a continuous increase was observed in the V group during the follow-up examinations (P =.0035, VFI = 2.50 plus minus 1.21, 1.14 plus minus 0.42 at 18 months, respectively).

CONCLUSION

Valvuloplasty combined with axial transposition of a competent tributary vein gives a better result than valvuloplasty alone at the 18-month follow-up. A competent valve in this location can be expected to improve VFI to a normal range.

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.

Pre-bypass quality assessment of the long saphenous vein wall with ultrasound and histology

OBJECTIVES

Pre-existing unsuspected wall changes in saphenous vein grafts have been implicated in the graft outcome. Pre-bypass assessment of the vein may identify grafts at high risk for failure. This study was conducted to evaluate preoperatively the quality of the long saphenous vein (LSV) wall with ultrasound and histology.

DESIGN

Prospective clinical study.

MATERIAL AND METHODS

Three particular LSV segments, ankle, knee and mid-thigh, were evaluated preoperatively by ultrasound in 40 limbs of 38 patients, candidates for coronary artery bypass grafting. The venous wall was characterised based on its thickness and echogenicity in three categories: normal, moderately and severely fibrotic. LSV specimens taken from the above sites were also grouped into the same three categories based on their fibrotic content found on histology.

RESULTS

In total, 89 vein specimens were evaluated. On ultrasound, 81 specimens were detected as normal (91%), seven as moderately (8%) and one as severely fibrotic (1%). On histology, only eight specimens were found normal (9%), 75 with moderate (84%) and six with severe fibrosis (7%). Similar wall characterisation with both examinations was found in only 19% (17/89) of the specimens. Eighty-one specimens (91%) had some degree of fibrosis on histology. Different grades of fibrosis were found on histology in different sites of the same vein.

CONCLUSIONS

Pre-existing wall changes are very common in vein grafts used for bypass surgery. However, the ultrasonic characterisation of the venous wall preoperatively cannot reliably identify these changes.