Extraperitoneal unilateral iliac artery bypass for chronic lower limb ischaemia

Extraperitoneal unilateral iliac artery bypass was used to treat chronic lower limb ischaemia in 105 patients (110 operations). This represented 20% of all operations for aorto-iliac disease. Unilateral iliac bypass was the preferred primary procedure for 99 operations, and was used to correct complications in one limb of a prior aortic bifurcation graft in the other 11. Ipsilateral femoropopliteal vein grafts were also performed in 45 legs (43%), prior to the iliac bypass in 18, as a synchronous operation in nine, and at a later date in 18 legs. This was a much higher proportion of combined operations than for patients by aortic bifurcation grafts (12%). Only 5 patients later required further proximal surgery, one for a blocked graft and four for contralateral iliac disease. The cumulative patency rate in surviving patients was 91% at 3 years. For the claudicants and for iliofemoral bypass operations, only one graft occluded, within 5 years, and no grafts occluded for operations where the superficial femoral artery was patent. The cumulative patency rates at 3 years were 85% for patients with critical ischaemia, 82% for ilioprofunda bypass operations, and 88% for operations where the superficial femoral artery was occluded. The cumulative foot-salvage rate in surviving patients initially treated for critical ischaemia was 77% at 3 years. The cumulative survival rate was 90% at 3 years. Extraperitoneal unilateral iliac bypass is now preferred as the primary operation for patients with apparent unilateral iliac disease causing severe ischaemia, if balloon dilatation is not appropriate or has failed.     

The effect of adjunctive arteriovenous fistula on prosthetic graft patency: a controlled study in a canine model

Bilateral 6 mm PTFE grafts were placed from the external iliac artery to the femoral artery with ligation of the intervening segment of the iliofemoral artery in 14 dogs. An arteriovenous fistula was constructed at the distal anastomosis on one randomly selected side in each animal while the contralateral graft served as a control. Graft follow-up ranged between 8 and 12 months in all animals. Serial arteriography was performed to confirm graft and fistula patency and demonstrated persistence of antegrade flow into the arterial tree distal to all patent bypasses. Femoral intraarterial pressures distal to patent grafts were identical on both sides in each animal throughout the study. Cumulative life-table patency rates showed higher patency for the arteriovenous fistula bypasses than the control grafts at all time intervals: 71% vs. 57% at 3 months, 48% vs. 25% at 6 months, and 40% vs. 22% at 12 months, respectively. This is the first controlled study that provides experimental evidence suggesting that these bypasses may produce increased patency of prosthetic arterial grafts and lends support to their use in a clinical, prospective, randomized study.     

Stenting for localised arterial stenoses in the aorto-iliac segment.

OBJECTIVE: to determine complications and patency following angioplasty (PTA) and stenting of aorto-iliac stenoses. Setting: District General Hospital in U.K. Design: prospective observational study. PATIENTS AND METHODS: between December 1994 and June 2000, 50 patients (38 men), median age 64 (41-89) years underwent aorto-iliac stenting. A total of 61 stents were placed. Indications were intermittent claudication in 38 and rest pain, ulceration or gangrene in 12. Sites stented were aorta 11, common iliac artery 32, external iliac artery 14, common and external iliac arteries two. Bilateral iliac procedures were carried out in nine. Two stents were used to correct residual stenoses after aortic stenting. Some 11 recurrent stenoses were treated. The other reasons for stenting were residual stenoses greater than 30% after PTA, tight calcified stenoses or when a stenosed iliac artery was being used as a donor prior to crossover or femoropopliteal bypass. RESULTS: two immediate technical failures occurred due to malposition. Residual stenoses were corrected by PTA. Two further patients sustained minor complications. None of the aortic stents occluded through two required secondary procedures. Primary-assisted patency was thus 100% at three years. Primary patency following iliac stenting for claudication and critical ischaemia were 97% and 86% at three years respectively. CONCLUSION: PTA and stenting of aorto-iliac stenoses can be safely achieved with durable results.     

A comparison of rapid-healing prosthetic arterial grafts and autogenous veins.

The patency rates and healing characteristics during a nine-month period of internal velour Dacron grafts, external velour Dacron grafts, and Sparks-Mandril grown grafts were compared with autogenous jugular veins when used to bypass short segments of the canine femoral artery. Graft thrombosis occurred in three of 11 external velour grafts, in six of 11 internal velour grafts, and in three of 11 Sparks-Mandril grafts, None of 33 autogenous veins occluded. Graft thrombosis was not correlated with the degree of graft healing but rather with a hyperplastic proliferative intimal lesion observed at the proximal anastomosis of the occluded grafts.     

The comparison of the graft patency after coronary artery bypass grafting using coronary angiography and multi-slice computed tomography.

OBJECTIVE: Coronary angiography (CAG) is the gold standard method in evaluating graft patency following coronary artery bypass grafting (CABG), even though there are several kinds of non-invasive methods. Recently developed multi-slice CT (m-CT), having effective scan times up to 0.25 s and multi-row detector array systems, enable rapid imaging of cardiac structures, including coronary arteries during one breath-hold. We compared m-CT with CAG for the evaluation of graft patency following CABG. METHODS: Forty-two patients having undergone m-CT and CAG within 3 months of CABG were studied. Twenty-three patients underwent conventional CABG and 19 off-pump CABG. A total of 125 grafts were used, including 42 left internal mammary arteries (LIMA), 25 radial arteries (RA), 3 right internal mammary arteries (RIMA) and 55 vein grafts. RESULTS: CAG showed a 96% (120/125) patency rate (1 LIMA, 2 RA and 2 vein grafts were occluded). m-CT showed a 98% (122/125) correct positive ratio with a sensitivity and specificity of 98 and 100%, respectively. The sensitivity in LIMA, RA, RIMA and vein grafts was 98, 91, 100 and 100%, respectively, with 100% specificity for all. There was an equivocal result in the competitive grafts with native coronary artery that were patent in the CAG, but faint opacification with no significant flow in the m-CT. CONCLUSIONS: This study showed that m-CT was very simple, useful and accurate in evaluating graft patency during the early post-operative period following CABG, even though there was an equivocal result in the competitive grafts with a native coronary artery.     

Ilio-femoral and femoro-femoral crossover grafting. Analysis of an 11-year experience

Experience with 131 crossover arterial bypass grafts for lower limb revascularization has been reviewed. Ninety-nine grafts were placed as a primary procedure for unilateral iliac artery occlusive (97) or aneurysmal (2) disease. In contrast 32 grafts were placed as a secondary procedure following the failure of a previous unilateral or bilateral conventional aorto-iliac reconstruction. Fifteen patients were not suitable for a crossover procedure without the addition of a concomitant donor limb inflow reconstruction. The one month operative mortality rate was 6.1%. The five-year cumulative patency rate was 71.4% +/- 6.0 in primary procedures and 38.1% +/- 11.3 in secondary procedures (p less than 0.05). No difference in the success rate was shown when the vein graft patency curve was compared with the synthetic graft patency curve. However, the use of a small caliber vein (6 mm or less) resulted in the lowest patency rate. No other factors affecting patency were found. This report tends to support the fact that ilio-femoral or femoro-femoral crossover bypass is a safe and effective procedure for managing unilateral iliac artery occlusive disease. With proper selection of patients, a wider use of the method is justified.     

The effect of preformed confluent endothelial cell monolayers on the patency and thrombogenicity of small calibre vascular grafts

Endothelial cell seeding has been proposed as a method to improve the patency rates in small calibre prosthetic vascular grafts. The seeding methods used at present leave much of the graft luminal surface devoid of endothelial cells and thus still significantly thrombogenic. We have developed a method to preform confluent endothelial cell monolayers, on the grafts prior to implantation, and this study investigates the effect of these monolayers on the early thrombogenicity and patency of polytetrafluoroethylene (PTFE) grafts. Small diameter PTFE grafts were seeded with canine endothelial cells obtained from the external jugular vein. Each of five dogs then received a graft seeded with its own cells and a contralateral, non-seeded control graft. At 1 and 10 weeks after graft implantation graft thrombogenicity was assessed by the use of Indium labelled platelets. The thrombogenicity index (TI) of each graft was determined from counts of gamma activity recorded over a period of 7 days. Grafts were subsequently removed at 12 weeks. At 1 week the mean TI for the seeded grafts was 0.123 (SD 0.019) and that for the controls 0.183 (SD 0.017) (p = 0.005). At 10 weeks only the seeded grafts could be assessed because all of the control grafts had occluded. At this point in time the seeded grafts had a mean TI of 0.159 (SD 0.011) (p = 0.047 vs. seeded at 1 week). By the time of removal at 12 weeks, all control grafts were occluded but only one of the seeded grafts had occluded (p = 0.025). In conclusion, the use of preformed, confluent endothelial cell monolayers for seeding prosthetic grafts significantly reduces the early graft thrombogenicity and improves graft patency. It does not, however, completely halt the increase in thrombogenicity which occurs during the early post-implantation period.     

An alternative to aorto-uni-iliac EVAR and femoro-femoral crossover in a patient having an aorto-iliac aneurysm with an occluded external iliac artery.

INTRODUCTION: An endovascular procedure for excluding an aorto-iliac aneurysm whilst simultaneously preserving one internal iliac artery is described in a patient with complex iliac pathology. REPORT: The procedure involved the use of Advanta V12 covered stents to bridge the gap between the contralateral limb of the main body of a custom-made Zenith stent graft and the internal iliac artery on the side of an external iliac artery occlusion. DISCUSSION: Minimal modifications to the standard design of modular stent grafts make it possible to treat high risk patient with complex pathology with minimal morbidity.     

Combined percutaneous transluminal angioplasty and extraanatomic bypass for symptomatic unilateral iliac artery occlusion with contralateral iliac artery stenosis

We have reviewed our experience with percutaneous transluminal angioplasty of contralateral iliac stenosis and extraanatomic bypass of the occluded iliac artery. Twenty-two men and nine women with a mean age of 65 years (range 46 to 84) presented with symptomatic iliac occlusive disease. Twenty-four (77%) had disabling claudication, four (13%) rest pain, and three (10%) ischemic tissue loss. Six (19%) had undergone previous vascular reconstructive procedures. All had an occluded iliac artery on the symptomatic side and greater than 50% stenosis of the contralateral iliac artery. Percutaneous transluminal angioplasty of the iliac stenosis was done prior to extraanatomic bypass, using polytetrafluoroethylene. There were six late deaths after discharge. The only significant complication was a femoral artery thrombosis which was corrected when the bypass graft was performed. Cumulative primary graft patency was 89% at one year and 81% at three years. The crossover graft occluded in six patients, five within 48 months of surgery, and one after nine years. One of these occluded grafts was salvaged by thrombectomy, for a secondary patency rate of 85% at three years. Two patients required aortobifemoral bypass, one an iliobifemoral bypass and one an ilioprofunda bypass. One patient operated upon for rest pain came to below-knee amputation. Mean resting ankle/brachial systolic pressure index increased significantly on the side of the iliac occlusion from 0.35 ±0.21 to 0.70 ± 0.20 (p < 0.05, paired t test) after the combined procedure. There was no significant difference in the mean resting ankle/brachial systolic pressure index on the contralateral side (0.60 ± 0.22 to 0.65 ± 0.27, ns). Combined iliac percutaneous transluminal angioplasty and femorofemoral bypass is a safe alternative to aortobifemoral bypass for selected patients with aortoiliac arterial occlusive disease. Presented at the Royal Australasian College of Surgeons, General Scientific Meeting, May 1989, Melbourne, Australia.     

An experimental study of the healing of velour grafts

An experimental study of implantation of velour grafts in the abdominal aorta or the external iliac artery of dogs was conducted with the object of evaluating the type of velour surface best fit for small-caliber artery implantation. Velour grafts measuring 4mm in diameter with differing velour surfaces were used as materials. Velour grafts now available on the market differ not only in velour surface but also in structure, notably in porosity and wall thickness. Hence each of the grafts used was reversed (i.e. inside out) and thus new grafts were prepared. These grafts were considered most suitable for making a comparative study of the effects of velour surface on healing. Macroscopic and histological findings revealed that each graft was good healing with the rate of patency as high as 84 percent. However, like Vasculour-D grafts, crimped grafts which preserve the crimp after implantation was significantly thicker at the internal valley than other grafts. Based on the findings of this experimental study non-crimped velour grafts were considered to be best fit for small-caliber artery implantation.     

Aorto-iliac/femoral reconstructions in patients with vasculogenic impotence

One hundred and forty-eight patients out of 386 undergoing aorto-iliac or aortofemoral bypass had preoperative impotence, 37 of these were diabetics. In all of them Doppler studies revealed a penile/brachial pressure index less than 0.6 and an abnormal waveform analysis. Nocturnal penile tumescence was investigated in 44 cases and found to be abnormal. Angiography showed unilateral or bilateral obstructive lesions of the hypogastric arteries in 80%, in addition to aortic, common and external iliac and femoral lesions. One hundred and thirty patients (87.8%) had straight aorto-iliac/femoral bypass grafts inserted without a direct attempt to revascularise the hypogastric arteries but 24 had distal anastomoses to the bifurcation of the common iliac artery. In the remaining 18 patients the hypogastric artery was reconstructed on one side by an additional bypass or reimplantation on the graft. In 22 of 106 patients (20.7%) undergoing aortofemoral bypass, 18 of 24 (75%) with the distal anastomosis to the iliac bifurcation, and 14 of the 18 (77.7%) with revascularisation of the hypogastric arteries, erectile function was regained. A good result was obtained in only five of the diabetic patients (13.5%). Our experience suggests that: (1) impotence, as indicated by non-invasive investigations, was vasculogenic in origin since patients with the most effective revascularisation of the hypogastric arteries had the best results; (2) when it is feasible, revascularisation of the hypogastric arteries should be carried out more often, during the aorto-iliac or aortofemoral reconstructions, particularly in younger impotent patients; (3) aorto-iliac revascularisation restores potency in only a few diabetic patients.     

Fate of bypass grafts onto totally occluded coronary arteries.

BACKGROUND: Chronically occluded coronary arteries often develop good collateralisation, that leads to retrograde perfusion of these vessels, as regularly seen in coronary angiograms. Retrograde perfusion constitutes a form of competitive flow, which in turn is associated with an increased risk for early bypass graft failure. The aim of our study is to investigate the patency rate of bypass grafts onto totally occluded coronary arteries, in the presence of retrograde flow. METHODS: Two groups of patients were followed up by cardiac catheterisation. One month after undergoing coronary artery bypass grafting. Group 1 (n=33) had coronary three vessel disease, with one totally occluded coronary artery and evidence of retrograde flow in the preoperative coronary angiogram. Group 2 (n=30) was the control group, with coronary three vessel disease and without totally occluded coronaries. We used internal mammary arteries and saphenous vein grafts as conduits. RESULTS: Thirty-six point thirty-six per cent of bypass grafts onto totally occluded coronaries were occluded one month postoperatively (n=12). Graft failure in the control group was 13.3%. Significance p=0.03. CONCLUSIONS: In view of our findings we conclude, that there is a significantly increased incidence of early graft failure, when totally occluded coronary arteries are revascularised, that show retrograde flow in the preoperative coronary angiogram.     

Improved adherence of genetically modified endothelial cells to small-diameter expanded polytetrafluoroethylene grafts in a canine model

Purpose: A significant limitation to using genetically modified endothelial cells (ECs) to seed prosthetic grafts before implantation has been poor cell adherence to the graft lumen. Methodologic changes to improve cell adherence were evaluated in a canine carotid interposition graft model using 4 mm interior diameter expanded polytetrafluoroethylene. Methods: ECs harvested from external jugular veins were grown in culture, with 80% of the cells from each culture transduced by incubation with an LXSN-type retroviral vector carrying a gene for human prourokinase and a neomycin resistance gene for selection in antibiotic G418. Control grafts had passive luminal coating with fibronectin and were seeded with transduced ECs immediately after G418 selection; these grafts were incubated for 2 days before implantation. Experimental grafts had fibronectin forcefully squeezed through the interstices and were seeded with ECs that had recovered in culture for 5 days after G418 selection; these grafts were incubated for 4 days before implantation. For each control (n = 9) and experimental (n = 12) graft, a graft prepared in the same fashion but seeded with the remaining autologous nontransduced cells was placed in the contralateral carotid artery. Grafts were explanted after 30 days and were evaluated for patency, thrombus-free surface area, and cell-free surface area. Results: No significant differences in patency rates were seen between any groups. The thrombus-free surface area was improved for experimental grafts (90%) compared with control grafts (76%), but this improvement did not achieve statistical significance. The cell-free surface area for transduced cells on experimental grafts was 65% compared with 96% for control grafts (p = 0.021) and was comparable with that for nontransduced cells on both control grafts (62%) and experimental grafts (51%; p = 0.201). Conclusions: Adherence of genetically modified endothelial cells to small-diameter expanded polytetrafluoroethylene grafts in an in vivo physiologic flow model is significantly improved when cells have a more prolonged recovery from G418 selection, when the graft lumen is more uniformly coated with fibronectin before EC seeding, and when seeded grafts are left longer in culture before implantation to develop cell lining stability. The short-term patency rate of these seeded grafts is not affected by increased cell retention; long-term graft patency data and luminal healing require further evaluation. (J Vasc Surg 1998;27:902-9.)     

血小板中cAMP与cGMP及血清LDL-ch对犬下腔静脉移植物内膜增生的影响

为探讨静脉系移植物通畅率的影响因素，对自体静脉碎片种植Ｄａｃｒｏｎ后植入下腔静脉（ＩＶＣ）的１３只犬及全血预凝Ｄａｃｒｏｎ后植入ＩＶＣ作对照的８只犬血清脂蛋白胆固醇、血小板环－磷酸腺苷（ｃＡＭＰ）、环－磷酸鸟苷（ｃＧＭＰ）及移植物内膜厚度进行了测定。结果：种植组通畅率（６１．５％）高于对照组（２５．０％），Ｄａｃｒｏｎ腔面术后２周完全内皮化；对照阻塞组与种植阻塞组血小板ｃＡＭＰ低于对照通畅组与种植通畅组，血清低密度脂蛋白胆固醇（ＬＤＬ－ｃｈ）高于对照通畅组与种植通畅组，前二组内膜厚度大于后二组。结果提示：内皮层不完整所致腔面前列环素及血小板ｃＡＭＰ减少，可能是静脉系移植物内膜增生的主要原因，高ＬＤＬ－ｃｈ血症可能对其有促进作用；人工血管内皮化，抗血小板与降血脂处理对预防内膜增生及提高通畅率可能有帮助。     

Comparison between externally stented and unstented PTFE vascular grafts

It has been suggested that external stenting of synthetic vascular prosthetic material may improve patency rates in the low flow situation or across joints. This study compared externally stented polytetrafluoroethylene (PTFE) vascular grafts placed across the hip joint in dogs with nonstented PTFE grafts in regard to patency. Twenty animals underwent bilateral common iliac to common femoral artery bypass with proximal ligation of the femoral artery. In each animal one groin was randomly assigned to receive stented PTFE and the other nonstented PTFE. One animal was sacrificed at 2 weeks for graft infection. Nineteen animals received 38 grafts that remained in place 90-120 days. Patency was confirmed with angiography prior to sacrifice. Overall patency was 65 per cent with no significant difference between the two types of graft. Eighteen of 19 dogs (95%) had both the stented and nonstented PTFE grafts either open or closed. It is concluded that intrinsic factors, rather than external graft support, are a more important influence on graft patency in this model.     

Noninvasive color Doppler inspection of small-diameter vascular grafts implanted in canine carotid and femoral arteries

To noninvasively evaluate a small-diameter vascular graft (approx. 4 mm in diameter) developed for coronary artery bypass application, a state-of-the-art color Doppler flow mapping system was applied to inspect various grafts implanted in 5 canines. The grafts, including Denaflex, Gore-Tex ePTFE, and Bioflow, were implanted interpositionally in the carotid and femoral arteries. Inspections were conducted with a 5 MHz linear vascular transducer at 6 weeks postimplantation and 12 weeks postimplantation, immediately prior to retrieval. In the carotid artery position, all 5 Denaflex grafts were patent throughout the implantation period while 2 of the 5 Gore-Tex grafts were occluded at 6 weeks, and 1 more was occluded at 12 weeks. In the femoral artery position, all 5 Denaflex grafts were patent at 6 weeks; however 2 were occluded at 12 weeks. For the Bioflow grafts at 6 weeks, 3 were patent, and 2 were occluded. The same results were observed at 12 weeks. The color Doppler inspection results indicated a higher patency rate in the carotid artery position than in the femoral artery position. Furthermore, the volumetric flow rate and the wall shear stress measured with the pulsed Doppler in the carotid artery were greater than in the femoral artery. These findings suggest that the hemodynamic "environment" in which the graft was implanted may affect the graft patency rate. The Doppler inspection results obtained at 12 weeks, identical with those observed after retrieval, demonstrated that color Doppler flow mapping is a reliable method to noninvasively inspect blood flow through small-diameter vascular grafts.     

Utility and reliability of endovascular aortouniiliac with femorofemoral crossover graft for aortoiliac aneurysmal disease

OBJECTIVE: The purpose of this study was to determine the early efficacy of endovascular aortouniiliac stent grafts with femorofemoral bypass graft in the treatment of aortoiliac aneurysmal disease. METHODS: We analyzed 51 consecutive patients from January 1997 to March 1999 with a mean follow-up of 15.8 months. Patients ranged in age from 44 to 93 years (mean, 75 years) with a mean aortic aneurysm diameter of 6.2 cm. Technical success was achieved in 50 patients; one patient required conversion to open repair intraoperatively. We placed 28 custom-made and 22 commercial devices. The mean operative time was 223 minutes. The endograft was extended to the external iliac artery in 42% of cases. The contralateral common iliac artery was occluded using either a closed covered stent or intraluminal coils. RESULTS: The median hospital stay was 4 days with an average intensive care unit stay of 0.25 days. There were no operative mortalities. Two patients died during follow-up from unrelated conditions. Endoleaks occurred in 11 patients (22%); seven patients (14%) required intervention (four catheter based, three operative). Other complications occurred in 38% of patients but were largely remote or wound related. One femorofemoral bypass graft occluded immediately postoperatively as a result of an intraprocedural external iliac dissection yielding a 98% primary patency and 100% secondary patency. Clinical success was achieved in 88% of patients. CONCLUSIONS: These data suggest that this strategy represents a reliable method of repair of aortoiliac aneurysmal disease and extends the capability of an endoluminal approach to patients with complex iliac anatomy.     

Preconditioning and proximal ligation did not influence the outcome of direct internal mammary artery bypass grafting in a canine model

The aim of this study was to assess the need for preconditioning and/or exclusion of competitive flow in minimally invasive coronary bypass grafting procedures (MICAB), to prevent early graft occlusion. Eight mongrel dogs (+/- 25 kg) were operated on under intravenous anaesthesia (sodium thiopenthal 15 mg/kg) and maintained with Halothan 1-2% and Pancurorium. A direct anastomosis between the left internal mammary artery and the left anterior descending coronary artery was performed, via anterior distal sternotomy, on the beating heart. Four dogs were preoperatively randomly conditioned by intravenous bolus injection of Diltiazem (0.0025 g/kg) prior to the procedure and after (meanwhile the left internal mammary artery takedown, the proximal coronary artery was snared during 15 min). In the absence of ECG changes or rhythm disturbances, a direct anastomosis of the left internal mammary artery and the left anterior descending coronary artery was performed. In four control dogs, direct MICAB procedure was done without preconditioning. The proximal left anterior descending coronary artery was occluded upstream of the arteriotomy in two dogs from both groups to exclude competitive flow from the native coronary artery. All the procedures were successful, except for one conditioned dog that sustained preoperative transmural anterior myocardial infarction. Cardiac enzymes (CK and CKMB) rose in all groups immediately after the procedure; this was not statistically significant between groups. All survivors were angiographically controlled after 6 to 8 weeks. They showed good patency of all grafts (mean thrombolysis in myocardial infarction-flow equals 2.86). There was perfect matching between the left internal mammary artery and left anterior descending coronary artery in the conditioned and proximal occluded group, which was contrary to the competitive flow in the control groups between the open left anterior descending coronary artery and the left internal mammary artery graft. Permeability of the left internal mammary artery grafts are not influenced by preconditioning nor exclusion of competitive flow in the MICAB technique for the canine model. Graft diameter and flow are merely the result of outflow conditions. In one case, preconditioning was followed by fatal myocardial infarction.     

Reliability of intraoperative flow measurements to determine early graft patency with simultaneous introduction of a new method for distal coronary artery run-off capacity

Intraoperative measurements of blood flow were made in 44 patients in whom a total of 112 venous bypass grafts were inserted. Blood flow through the graft was measured by a standard electromagnetic device as well as by a new method, consisting of a roller pump run-off system. At an average of 5 months after operation all patients underwent control coronaro-angiography. Overall patency-rate was 86.6%. Using the standard method mean flow in the patent grafts was 78 ml/min and 39 ml/min in the occluded grafts. Using the new run-off method mean flow in the patent grafts was 142 ml/min and 78 ml/min in the occluded grafts. It is concluded that measuring distal coronary artery run-off capacity provides a reliable index for predicting patency rate. For several reasons roller-pump run-off measurement has advantages over the generally used electromagnetic measurements.     

Analysis of factors influencing early patency of saphenous vein grafts

To determine factors affecting early patency of saphenous vein grafts, 140 grafts in 65 patients were studied angiographically within 2 months after operation. Twenty of the 140 grafts were occluded. Sixteen variables were extracted from the angiographic findings, intraoperative measurements, clinical characteristics, and biochemical data. The univariate and multivariate analyses were performed to assess their predictive value. Of 16 variables, 3 (coronary artery internal diameter, graft flow, and coronary artery resistance) correlated significantly with graft patency in the univariate analysis. The multivariate analysis selected coronary artery resistance, coronary artery internal diameter, and degree of proximal stenosis as predictors of early graft patency. Of these 3 factors, the coronary artery resistance influenced graft patency mostly. Therefore, the coronary artery resistance was considered to be the most reliable predictor of early graft patency.