Relationship of femorodistal bypass patency to clinical outcome. Iloprost Bypass International Study Group

The role of infrapopliteal angioplasty

Infrapopliteal percutaneous transluminal angioplasty (PTA) is currently indicated in patients with critical limb ischaemia (CLI). It may be performed after femoral angioplasty or bypass surgery, to improve outflow and hence patency of the proximally treated segment. Patients with CLI are typically elderly with multiple co-morbidities and limited life expectancy and therefore, a procedure, which is minimally invasive with reduced morbidity and mortality but lesser long-term patency, may be more appropriate than a more invasive procedure with better long-term patency. Clinical success is superior to angiographic patency, because once healing has occurred, should the artery restenose or occlude, collateral flow can be sufficient to preserve tissue integrity if there is no further injury. Although no prospective randomized trials have been performed, the reported limb-salvage rates of PTA are comparable with surgery. As PTA carries a lower morbidity and mortality, shorter hospital stay and does not preclude surgery, it is ideal for this group of patients who are high-risk surgical candidates. Improvements in guide-wire and catheter technology and recanalization techniques mean that very long stenoses or occlusions, and multiple lesions can be treated successfully. At the current time, PTA is the treatment of choice for infrapopliteal occlusive disease; experience with the use of stents in this territory is increasing but currently insufficient to justify their primary use.

Limb salvage after infrainguinal bypass graft failure

OBJECTIVE

The purpose of this study was to examine the outcome of patients in whom an infrainguinal bypass graft failed.

METHODS

This was a retrospective analysis of consecutive patients undergoing infrainguinal bypass grafting in a single institution over 8 years.

RESULTS

Six hundred thirty-one infrainguinal bypass grafts were placed in 578 limbs in 503 patients during the study period. The indication for surgery was limb-threatening ischemia in 533 patients (85%); nonautologous conduits were used in 259 patients (41%), and 144 (23%) were repeat operations. After a mean follow-up of 28 +/- 1 months (median, 23 months; range, 0-99 months), 167 grafts (26%) had failed secondarily. The rate of limb salvage in patients with graft failure was poor, only 50% +/- 5% at 2 years after failure. The 2-year limb salvage rate depended on the initial indication for bypass grafting: 100% in patients with claudication (n = 16), 55% +/- 8% in patients with rest pain (n = 49), and 34% +/- 6% in patients with tissue loss (n = 73; P <.001). The prospect for limb salvage also depended on the duration that the graft remained patent. Early graft failure (<30 days; n = 25) carried a poor prognosis, with 2-year limb salvage of only 25% +/- 10%; limb salvage was 53% +/- 5% after intermediate graft failure (<2 years, n = 110) and 79% +/- 10% after late failure (>2 years, n = 15; P =.04). Multivariate analysis revealed shorter patency interval before failure (P =.006), use of warfarin sodium (Coumadin) postoperatively (P =.006), and infrapopliteal distal anastomosis (P =.01) as significant predictors for ultimate limb loss.

CONCLUSION

The overall prognosis for limb salvage in patients with failed infrainguinal bypass grafts is poor, particularly in patients with grafts placed because of tissue loss and those with early graft failure.

Radiological Investigation and Treatment of the Critically Ischemic Limb—A Review

The contribution of radiological investigation and treatment in the management of the critically ischemic lower limb is reviewed. The methods of classifying and assessing the cause, level, and severity of the arterial disease causing the ischemia are discussed with comparison of the relative merits of the various invasive and noninvasive techniques of investigation. The development of the methods of interventional radiological management is described with an indication of the relative success of the different techniques. Newer interventional developments, including intravascular brachytherapy and gene therapy are discussed.

Reintervention as a clinical trial endpoint after peripheral arterial bypass surgery

BACKGROUND

Graft patency is usually the primary endpoint in studies of peripheral arterial bypass surgery, but gives only a limited indication of clinical outcome. The aim of this study was to evaluate reintervention as a study endpoint after femorodistal bypass surgery.

METHODS

The database from a multicentre, prospectively planned study of 517 patients undergoing femorodistal bypass for severe ischaemia was used to investigate the predictive value of technical endpoints. Clinical symptoms, graft patency, vascular interventions and clinical outcomes were recorded for 12 months after operation.

RESULTS

Complete follow-up data were obtained on 498 patients (96 per cent). Success in terms of patients' need for reintervention agreed with clinical outcome in 90 (95 per cent confidence interval (c.i.) 87-93) per cent of cases. Primary and secondary patency agreed with the clinical outcome in 80 (95 per cent c.i. 77-84) and 81 (95 per cent c.i. 78-85) per cent of patients respectively. However, the best agreement with clinical outcome was obtained from the composite endpoint of 'patient alive without reintervention': 92 (95 per cent c.i. 90-94) per cent.

CONCLUSION

Recording the number of patients who did not need reintervention for 12 months after femorodistal bypass gave a more accurate assessment of the number with clinical improvement than was obtained by recording bypass graft patency. Inclusion of patient survival in a composite endpoint increased the clinical relevance of this endpoint in patients with severe ischaemia who had femorodistal bypass surgery.

The natural history of intermediate and critical vein graft stenosis: recommendations for continued surveillance or repair

OBJECTIVE

Duplex ultrasound surveillance (DUS) after autogenous lower extremity bypass grafting is controversial. Specific criteria mandating graft revision are not uniform. It has been suggested that grafts harboring critical stenoses undergo revision, whereas those with intermediate stenoses undergo arteriography with selective repair. We sought to define the natural history and determine the risk of graft occlusion associated with unrepaired vein graft stenoses.

METHODS

We analyzed serial vascular laboratory and clinical data of 156 autogenous infrainguinal vein grafts in 142 patients. Grafts were categorized into three groups according to the first DUS-detected (index) lesion: (1) normal (peak systolic velocity [PSV] < 200 cm/s, velocity ratio [V(r)] < 2); (2) intermediate stenosis (200 cm/s < PSV < 300 cm/s, 2 < V(r) < 4); and (3) critical (PSV > 300 cm/s, V(r) > 4). Our policy was to repair grafts with critical lesions and monitor all others. The risks of stenosis progression, graft revision, and graft thrombosis for each group were compared.

RESULTS

Serial DUS was normal in 100 (64%) grafts. The incidence of graft thrombosis in the normal group was 3% per year (mean follow-up, 27.5 months). Intermediate lesions developed in 32 grafts (20%) and were followed. Among these 32 grafts with intermediate stenoses, 63% progressed to critical and were revised, and 32% resolved or stabilized (mean follow-up, 26 months). Only one graft occlusion occurred in grafts with intermediate lesions subjected to serial DUS monitoring (incidence 1.5% per year, P = not significant). In the third group, 16 of 25 grafts with critical lesions were successfully revised and remain patent. In nine cases, critical lesions were not repaired, resulting in seven (78%) occlusions, all within 4 months of DUS detection.

CONCLUSIONS

Serial surveillance is safe and effective for grafts with intermediate stenoses. The graft occlusion rate for such grafts with careful monitoring is no different from grafts without stenosis, and therefore, arteriography is not indicated in the absence of progression to critical stenosis. The short-term risk of graft occlusion in the presence of an unrevised critical stenosis is nearly 80%. These data have important clinical implications concerning the natural history of vein graft lesions.

Prospective trial of infrapopliteal artery balloon angioplasty for critical limb ischemia: angiographic and clinical results

PURPOSE

To evaluate the safety and efficacy of infrapopliteal percutaneous transluminal angioplasty (PTA) as a primary treatment of chronic critical limb ischemia in a prospective trial.

MATERIALS AND METHODS

Infrapopliteal PTA was performed on 72 limbs of 60 patients (mean age, 72 y; range, 38-92 y) and patients were followed for 12-24 months.

RESULTS

The primary angiographic success rate for the stenoses was 84% (102 of 121) and that for the occlusions was 61% (41 of 67) with corresponding restenosis rates of 32% and 52% at follow-up angiography performed a mean of 10 months after primary PTA. The rate of major complications was 2.8% (access site pseudoaneurysms in two patients). The primary clinical success was 63% (45 of 72). A 48% cumulative primary patency rate, a 56% secondary patency rate, and a 80% cumulative limb salvage rate were registered at 18 months, as determined with use of Kaplan-Meier analysis. Lack of angiographic improvement at the site of the most severe ischemia and renal insufficiency (serum creatinine level > 130 micromol/L) were independent predictors of poorer long-term clinical results, as determined with use of Cox multiple regression analysis.

CONCLUSIONS

Infrapopliteal PTA is a feasible primary treatment of chronic critical limb ischemia with moderate primary angiographic and clinical success, a low complication rate, and a cumulative limb salvage rate comparable with surgical techniques.

Adjuvant medical therapy in peripheral bypass surgery

BACKGROUND

A review was conducted of published clinical trials of adjuvant medical therapy in infrainguinal bypass procedures to evaluate the strength of the evidence for the use of various agents.

METHODS

Trials were identified by literature search. The methods used were reviewed and the results with each agent tested were assessed taking into account the soundness of the study design.

RESULTS

Thirty-three studies were identified; fewer than half had a randomized and double-blind design. Most were single-centre studies including a mixture of different surgical procedures and patients with varying degrees of lower limb ischaemia. Clinical outcomes were seldom reported. The median sample size was 61. The median follow-up duration was 12 months, but was often not standardized for all patients in a trial. Only aspirin in prosthetic grafts and ticlopidine in vein grafts have been shown in well designed, double-blind, randomized, controlled trials to reduce the likelihood of occlusion in infrainguinal bypass grafts.

CONCLUSION

The majority of the trials reviewed had significant deficiencies in their design, reducing the reliance that can be placed on their results. Further studies are required to investigate adequately the effectiveness of existing medical therapies for the maintenance of infrainguinal bypass grafts.