Infrainguinal Vein Bypass Grafts Research Articles

Impact of Diabetes Mellitus on Infrainguinal Bypass Grafting

The purpose of this study was to examine the role of diabetes mellitus (DM) in infrainguinal bypass graft outcome. One hundred forty-four patients who underwent 170 infrainguinal bypass grafts from 1990 to 1995 were reviewed retrospectively. Seventy-eight patients (94 bypasses) had DM and were followed for an average of 15.4 months; 13 patients were lost to follow up. The mean age was 68 years; 44 (56.4%) were men. The major indication for intervention was limb salvage for the DM (87/94, 92.6%) and non-DM (56/76, 73.7%) groups. No significant difference was found for perioperative wound complications, hematoma, myocardial infarction, or deep venous thrombosis between the DM and non-DM groups. Early mortalities were three for DM and one for non-DM patients. No significant difference was found between primary patency p = 0.71 , secondary patency p = 0.32 , limb salvage p = 0.99 , and survival p = 0.72 between DM and non-DM groups. DM patients were more likely to have significant tissue loss p = 0.009 and a longer hospital stay p = 0.01 . In conclusion, infrainguinal vein bypass grafting can be performed successfully in diabetic patients with comparable patency and limb-salvage rates to those without DM.

Bilateral infrainguinal vein grafts and the incidence of vein graft stenosis

To elucidate the incidence of significant vein graft stenosis in patients who have undergone bilateral infrainguinal vein grafts. Between 1987 and 1996, 22 patients were identified from our vascular studies database as having undergone bilateral infrainguinal vein bypass grafting. Data was obtained from the vascular studies database and by case note review. All patients had been part of a vein graft surveillance programme. Of the 22 patients with bilateral vein grafts, eight were excluded from further analysis because one or more of their grafts failed within 30 postoperative days. In the remaining 14 patients (28 vein grafts) there were 15 primary vein graft stenoses. Six patients (43%) had bilateral vein graft stenoses, which is significantly higher (p = 0.0008) than the predicted value of 9%, for developing bilateral vein graft stenoses. For those patients who developed a vein graft stenosis in their first grafted limb (9/14), 67% (6/14) subsequently developed a vein graft stenosis in their second grafted limb. Patients who develop vein graft stenosis in one limb are at a greater risk of developing a contralateral vein graft stenosis if that limb is grafted. This may well be due to individual vein morphology or unidentified systemic factors that play a role in the aetiology of vein graft stenosis.

Inducible nitric oxide synthase expression in human vein grafts

The patency of vascular reconstructive procedures is limited by the development of intimal hyperplasia (IH). Nitric oxide (NO) seems to be beneficial in abrogating this process. Currently, there is little information concerning inducible nitric oxide synthase (iNOS), the enzyme responsible for NO synthesis, and human vein grafts. The purpose of this study was to examine iNOS gene expression in human aortocoronary vein grafts (ACVG) and infrainguinal vein bypass grafts (IVG). Nonthrombosed sections from ACVG (n = 5), IVG (n = 5), and control saphenous vein (SV; n = 4) were harvested and processed for RNA isolation. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was performed on samples using 32P radioactively end labeled primers. Glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) was the internal control, and results were expressed as iNOS pmol/GAPDH pmol. There was a significant increase in the iNOS gene expression in the ACVG (0.049 +/- 0.01) when compared with IVG (0.019 +/- 0.001) or normal SV (0.011 +/- 0.002; P < or = 0.05). There was no significant difference between normal vein and the infrainguinal grafts. Sequencing of a fragment of the amplified 428 bp gene product confirmed 84% homology with the available gene bank human sequence. This study proves that iNOS is expressed in human vein bypass grafts. Additionally, there is a significant elevation of iNOS message in human ACVGs compared with IVG or normal SV. This difference may be the result of the unique vascular beds supplied by these grafts. Ultimately, manipulation of iNOS expression may lead to therapies to alleviate IH in these grafts.

Thrombolysis of occluded infrainguinal vein grafts: predictors of outcome.

The purpose of this study was to identify factors that influence graft patency and limb salvage rates after thrombolysis of occluded infrainguinal vein grafts. The records of patients who underwent percutaneous catheter-directed thrombolysis of occluded infrainguinal vein bypass grafts at our institution between 1985 and 1995 were reviewed. Life table analysis was used to determine survival and patency differences. Univariate and multivariate analyses were used to identify the patient-specific factors that affected outcomes. Forty-four patients with 44 thrombosed infrainguinal vein grafts underwent thrombolysis with urokinase. The thrombolysis-related mortality rate was 2%, and nonfatal complications occurred in 16%. Thrombolysis was unable to restore graft patency in 25% of grafts (11 of 44). Of the remaining 33 successfully lysed grafts, 88% required adjunctive surgery or percutaneous transluminal angioplasty after thrombolysis. Overall, the primary graft patency rate was 25% at 1 year and 19% at 2 years after thrombolysis. Considering only successfully lysed grafts, the primary patency rate improved to 34% at 1 year and 25% at 2 years. Multivariate analysis revealed that the graft patency rate was substantially better in patients without diabetes and in vein grafts that had been in place for longer than 12 months (p < 0.01). The limb salvage rate was significantly improved by successful thrombolysis (63% at 2 years vs 31% if lysis failed; p < 0.01). The patient survival rate was high-89% 2 years after thrombolysis. Even with adjunctive therapy, vein graft thrombolysis is unlikely to yield durable patency overall. However, successful thrombolysis improves limb salvage rates and may be beneficial in patients without diabetes who have mature vein grafts but who do not have options for other autogenous revascularization procedures.

Measurement of Vascular Input Impedance in Infrainguinal Vein Grafts

The purpose of this investigation was to measure vascular input impedance in infrainguinal vein grafts and assess the importance of clinical and hemodynamic parameters in predicting graft patency. Fifty-seven patients undergoing infrainguinal vein bypass grafting for limb salvage (n = 40) or claudication (n = 17) were prospectively studied. At the time of revascularization, simultaneously acquired intraluminal pressure and blood flow waveforms were digitized at 200 Hz and subjected to Fourier transformation in near real-time. Input impedance was calculated at baseline (immediately after unclamping) and after stimulation with either papaverine or completion arteriography. Resistance (Rin) was calculated as mean pressure divided by mean blood flow (Q). Characteristic impedance (Z0) was calculated as the mean of harmonics 3-10. Intraoperative data acquisition required approximately 5 min, utilized the completion angiography cannula already in place, and was uncomplicated in all patients. Stimulation with either papaverine or arteriography resulted in increased Q (72 +/- 7 to 146 +/- 11 ml/min, p < 0.001), decreased Rin (126 +/- 13 to 52 +/- 4 x 10(3) dyne.s.cm-5, p < 0.001), and slightly decreased Z0 (18 +/- 2 to 15 +/- 1, p = 0.002). After a mean follow-up of 20 months, the 2-year primary patency, secondary patency, limb salvage, and survival rates were 61 +/- 8%, 74 +/- 7%, 76 +/- 6%, and 86 +/- 6%, respectively. Primary patency was not associated with any of the clinical variables studied including age, sex, smoking history, history of previous vascular surgery, hypertension, coronary artery disease, diabetes mellitus, creatinine, indication for revascularization (claudication versus limb salvage), anesthesia (general versus regional), or level of distal anastomosis (popliteal versus infrapopliteal). Furthermore, there was no association between primary patency and baseline Q, baseline Rin, or stimulated Z0. However, using univariate analysis, patency was positively associated with decreased stimulated Rin (p = 0.002), elevated stimulated Q (p = 0.006), and decreased baseline Z0 (p = 0.02). Multiple regression analysis identified stimulated Rin as the only independent predictor of primary patency (p = 0.002). Stimulated Rin > or = 50 x 10(3) dyne.s.cm-5 was 71% sensitive and 65% specific for graft failure. It is concluded that 1) vascular input impedance can be simply and reliably measured in the operating room, and 2) elevated stimulated Rin is an independent predictor of primary patency.

True aneurysms of infrainguinal vein bypass grafts: The need for active, not passive management

Aged 54, patient A underwent bilateral above-knee, fermoropopliteal bypass grafting using autologous, reversed, saphenous vein. Twelve years later, he presented with an asymptomatic swelling in the right mid-thigh. Ultrasound demonstrated a 4 cm diameter aneurysm in the mid-portion of the vein graft. A conservative polic~ monitoring the aneurysm was adopted. Within 4 months however, the swelling increased very rapidly in size causing discomfort and numbness in the thigh. Repeat ul t rasound scanning showed an increase in diameter to 6 cm. The aneurysmal vein graft (Fig. la) was resected promptly, and a replacement polytetrafluorethylene (PTFE) graft inserted. Histology of the aneurysm wall demonstrated changes typically associated with localised atheromatous disease.

Nature and management of duplex abnormalities encountered during infrainguinal vein bypass grafting

This study was undertaken to evaluate the application of duplex scanning during infrainguinal vein grafting procedures to verify vein conduit preparation, anastomotic patency, and graft hemodynamics. Between 1991 and 1995, 275 infrainguinal vein bypasses (in situ, 114; reversed, 82; nonreversed translocated, 48; spliced alternative/arm vein, 31) to the popliteal (n = 116) or an infrageniculate artery (n = 159) were scanned during surgery for sites of color Doppler flow abnormality. Duplex-detected defects were graded with peak systolic velocity and velocity ratio criteria. Sites that demonstrated highly disturbed flow (peak systolic velocity > 180 cm/sec, velocity ratio > 2.4) were immediately revised by direct repair, patch angioplasty, or interposition grafting. Intraoperative duplex scanning prompted revision of 50 abnormalities in 43 of the 275 grafts (16%), including 32 vein and seven anastomotic stenoses, nine vein segments with platelet thrombus, and two bypasses with low flow. The intraoperative revision rate was lowest (p < 0.02) for reversed saphenous vein bypasses (7%) compared with other grafting techniques (in situ, 20%; nonreversed translocated, 15%; spliced alternative vein, 23%). The revision rates of popliteal and tibial bypasses were similar (14% vs 17%). A normal result shown by intraoperative scan (235 bypasses) was associated with a low 90-day thrombosis (0.4%) and revision (2%) rate, whereas six of 15 grafts (40%) with residual and 13 of 25 grafts (52%) with unrepaired duplex abnormalities required corrective procedures (p < 0.001). One graft failed within 3 months (secondary patency rate, 99%). Intraoperative duplex scanning accurately predicted the technical adequacy of infrainguinal vein grafts and was particularly useful in assessing bypasses constructed with valve lysis techniques or alternative veins. Early graft revisions indicated by duplex monitoring for thrombosis or stenosis were the result of a progression of residual defects and platelet thrombus formation rather than inadequate graft run-off flow.

The Relationship Between Arm-Ankle Pressure Difference and Peak Systolic Velocity in Patients With Stenotic Lower Extremity Vein Grafts

The relationship between the measured arm-ankle pressure difference (AAPD), or the ankle/arm index (AAI), and the focal peak systolic velocity (PSV) at stenotic sites of infrainguinal vein grafts has not been determined. We attempted to relate these two parameters. We used Doppler systolic pressures and duplex ultrasonography to study 35 infrainguinal vein bypass grafts followed in a surveillance protocol. The following graft groups were identified: grafts in nondiabetic patients (n = 26), grafts in diabetic patients (n = 9), nonrevised stenotic grafts (n = 14), revised stenotic grafts (n = 14), and normal grafts (n = 7). AAPD and AAI were measured in both lower extremities. Pressure gradients across graft stenoses were indirectly estimated using the modified Bernoulli equation (delta P =4V2). Measured AAPDs and estimated pressure gradients showed moderate correlation in nondiabetic (r = 0.58) and diabetic (r = 0.63) patients. Correlation was fair (r = 0.3) prior to graft revision. There was no correlation (r = 0.1) in the nonrevised stenotic grafts. For individual patients with stenotic grafts who were followed in consecutive visits, the correlation varied from none to good (r range 0.01 to 0.71). We conclude that there is a lack of consistent correlation between the measured AAPD, or AAI, and the estimated stenotic graft pressure gradient. This finding illustrates the limitation of the AAI as a monitoring test to predict failure of stenotic infrainguinal vein grafts.

Duplex scan surveillance of infrainguinal prosthetic bypass grafts

Purpose: Surveillance protocols of infrainguinal vein bypass grafts have almost universal acceptance. To date corresponding studies of prosthetic grafts have not been carried out. We have performed a prospective 4-year duplex scan follow-up on polytetrafluoroethylene grafts to assess the usefulness of a surveillance program of prosthetic bypass grafts in preventing graft failure.Methods: Over 4 years 69 infrainguinal polytetrafluoroethylene grafts in 56 patients were studied at six monthly intervals by our vascular laboratory. Full duplex scan mapping of the grafts and inflow and outflow arteries and standard ankle pressure measurements were performed. A midgraft peak flow velocity was also measured.Results: Over 4 years 27 (39.1%) grafts occluded without any predictive changes in the preceding duplex scan examination. Of the 42 (60.9%) grafts that remained patent, only four developed stenoses (three at the proximal anastomosis and one at the distal anastomosis) that were amenable to intervention. Changes in ankle pressures or midgraft flow velocity did not predict failure.Conclusions: The low yield of remediable disease does not justify the cost of duplex scan surveillance of infrainguinal prosthetic bypass grafts.

The utility and durability of vein bypass grafts originating from the popliteal artery for limb salvage

Short vein grafts originating from sites distal to the common femoral artery have been reported to be useful in selected patients with tibial artery disease. From 1987 to 1993, we performed 504 consecutive infrainguinal vein bypass grafts, of which 56 (11%) originated from the popliteal artery, 25 above and 31 below the knee. The patients were 16 women and 37 men, with a mean age of 62.4 years. Eighty-seven percent were diabetic, 57% had clinically obvious coronary artery disease, and 28% had end-stage renal disease (ESRD). The indication for surgery was ulceration or gangrene in 93% of cases. We preferentially used reversed greater saphenous vein harvested from the thigh to optimize conduit quality and avoid lower leg wound complications. The outflow artery sites were: dorsal pedal (17), posterior tibial (14), peroneal (10), anterior tibial (8), lateral or medial plantar (5), and sequential tibial (2). All patients were followed postoperatively with serial duplex surveillance. The mean follow-up was 12.5 months (range 1 to 66). In-hospital mortality was 5.4%. Mortality at 24 months was 19% overall and 38% in patients with ESRD. Limb salvage was 77% at 3 years, 92% in patients with normal renal function versus 59% in those with ESRD (P < 0.003). Primary graft patency by life-table analysis was 94% at 1 month and 84% at 3 years. Five patients with patent grafts required amputation, 4 early and 1 late. Eight months after surgery, 1 patient (1.8%) developed superficial femoral artery stenosis which was diagnosed by duplex surveillance and successfully treated by percutaneous transluminal balloon angioplasty. Vein bypass grafts originating from the popliteal artery are effective and durable. Proximal disease progression rarely poses a significant threat to long-term graft patency. Patients with ESRD, blind tibial outflow tracts, and extensive forefoot lesions appear to be at increased risk of limb loss even with continued graft patency.

Role of angioscopy in reoperation for the failing or failed infrainguinal vein bypass graft.

The purpose of this retrospective study is to review our ongoing experience with the use of angioscopy during reoperation for failed or failing infrainguinal vein bypass grafts and define the role of angioscopy in the management of this clinically demanding patient group. All hospital records, arteriograms, and intraoperative angioscopic video recordings of 79 consecutive failed or failing grafts (76 patients) examined with angioscopy during reoperation between 1987 and 1993 were reviewed. Clinical and intraoperative data, comparison of the preoperative arteriogram and intraoperative angioscopic findings, and surgical decisions or interventions resulting from the additional angioscopic findings were collated and analyzed according to a predetermined protocol. Sixty-six additional angioscopic findings were noted during the 79 reoperations and resulted in 61 additional interventions and surgical decisions with salvage of all or part of the graft in 90.9% in the early (< 30 day) failed (group 1), 84.6% in the late (> 30 day) failed (group 2), and 90.3% in the late (> 30 day) failing grafts (group 3). The amount of residual thrombus within the graft, as assessed by angioscopy after all interventions, was the critical determinant for overall early graft patency (p < 0.001) and long-term patency for all the subgroups after reoperation (group 1, p < 0.001; group 2, p = 0.0016; and group 3, p = 0.0194). Intraoperative angioscopy has an important role in these challenging procedures. It provides additional and useful information that not only influences the conduct and extent of the reoperative surgery but may provide insights into the pathogenesis of graft failure.

Angioscopically directed interventions improve arm vein bypass grafts

Our purpose was to determine the incidence and segmental distribution of intraluminal disease in the arm veins of patients in whom saphenous vein was unavailable or inadequate for bypass, determine whether angioscopic evaluation and directed interventions can upgrade the quality of arm vein conduit and improve early graft patency, and describe the angioscopic technique of in situ retrograde arm vein inspection. Retrospective review of 109 infrainguinal arm vein bypass grafts in 104 patients performed with intraoperative angioscopic vein preparation and monitoring between August 1989 and March 1992 was undertaken. Four additional arm veins harvested were discarded because of diffuse disease. Intraluminal disease was noted in 71 (62.8%) of 113 arm veins, "webs" in 61 (54%), vein sclerosis in 25 (22.1%), localized stenosis in 11 (9.7%), and thrombus in 7 (6.2%). Intraluminal disease was most common in the cephalic (forearm 49.2%; arm 35.1%) and median cubital (33.3%) veins and least common in the basilic vein (11.7%). Eighty-three angioscopically directed interventions in 68 of 71 abnormal arm veins resulted in upgraded vein conduit quality in 47 (66.1%) of 71. Primary patency (< 30 days) was 99 (90.8%) of the 109 grafts, 85 (95.5%) of 89 grafts with normal or upgraded quality conduits, and 14 (70%) of 20 inferior-quality grafts (p = 0.0024). These differences persisted through 1 year by life-table analysis, (p < 0.001). Not only is the routine use of the angioscope in arm vein bypass grafting a sensitive technique to detect the intraluminal diseases so prevalent in arm veins but it can also direct endoluminal and surgical interventions that upgrade the quality of the vein conduit and improve early graft patency.

Occluded Infrainguinal Vein Bypass Grafts. Are Secondary Alloplastic Procedures Worthwhile?

Occlusion of an infrainguinal saphenous vein bypass presents an unresolved problem of further treatment in patients with threatened limbs. The implantation of alloplastic grafts is an attempt to possibly avoid amputation. The authors report 56 patients who were treated by secondary alloplastic grafts after occlusion of their vein bypass. All secondary procedures were performed for limb salvage. The median time of patency of sequential combined saphenous vein plus an additional alloplastic bypass was sixteen months. Following a reocclusion of the secondary grafts, 45 % required major amputation. Nevertheless, the median period of limb salvage was fifty-four months. Therefore, secondary alloplastic grafts seem to be a reasonable procedure in the treatment of threatened limbs after occlusion of an infraginguinal saphenous vein bypass, if one takes the limited life expectancy of sixty-four months into account for these patients.

The use of sartorius muscle rotation-transfer in the management of wound complications after infrainguinal vein bypass: A report of eight cases and description of the technique

Although rare, major wound breakdown after infrainguinal bypass resulting in vein graft exposure carries the risk of vein graft disruption with threat to both life and limb. The use of sartorius muscle rotation-transfer specifically in the management of exposed autogenous infrainguinal vein grafts has not been previously described. Eight patients were evaluated for major wound disruption resulting in graft exposure after infrainguinal vein bypass. Soft tissue coverage was provided in all eight cases by means of a distally based sartorius muscle rotation flap. There was no instance of postoperative death, graft thrombosis, secondary hemorrhage, or persistent infection. Late follow-up has shown continued satisfactory results. We conclude that effective soft tissue coverage and salvage of exposed infrainguinal vein bypass grafts can be accomplished in selected cases by means of sartorius muscle rotation-transfer.

The use of sartorius muscle rotation-transfer in the management of wound complications after infrainguinal vein bypass: a report of eight cases and description of the technique.

Although rare, major wound breakdown after infrainguinal bypass resulting in vein graft exposure carries the risk of vein graft disruption with threat to both life and limb. The use of sartorius muscle rotation-transfer specifically in the management of exposed autogenous infrainguinal vein grafts has not been previously described. Eight patients were evaluated for major wound disruption resulting in graft exposure after infrainguinal vein bypass. Soft tissue coverage was provided in all eight cases by means of a distally based sartorius muscle rotation flap. There was no instance of postoperative death, graft thrombosis, secondary hemorrhage, or persistent infection. Late follow-up has shown continued satisfactory results. We conclude that effective soft tissue coverage and salvage of exposed infrainguinal vein bypass grafts can be accomplished in selected cases by means of sartorius muscle rotation-transfer.