A prospective patient observational study of the role of hyperhomocysteinemia in restenosis in patients undergoing infrainguinal angioplasty or bypass procedures.

AIM: The aim of this study was to examine the correlation between elevated plasma homocysteine (HCy) and restenosis/occlusion in patients undergoing infrainguinal angioplasty or bypass grafting. METHODS: Fifty-three patients presenting to the Northern Vascular Unit were sequentially recruited to the study and prospectively followed up for 12 months post-infrainguinal angioplasty or bypass surgery. Plasma HCy was measured preprocedure and at least 3 months postprocedure using the Abbott IMx system. Hyperhomocysteinemia (HHCy) was taken at a level >15 microM/L. All patients were serially duplex scanned at 6 weeks, and 3, 6, 9 and 12 months. Kaplan-Meier analysis was performed to assess the restenosis/occlusion rate in patients with HHCy versus controls. Analysis of correlation between risk factors for restenosis/occlusion was performed using the Pearson correlation coefficient. In addition, logistic regression analysis was performed. RESULTS: Forty-eight percent of procedures was performed in patients with HHCy. There were 18 graft stenoses/occlusions, and 13 restenoses/occlusions postangioplasty. HHCy did not correlate with an increased risk of restenosis/occlusion (P=0.79). There was a significant correlation between HCy, age, folate and cholesterol levels. Logistic regression analysis revealed no factors that correlated with failure of therapeutic intervention. CONCLUSIONS: This study does not support the hypothesis that HHCy is associated with an increased risk of restenosis after vascular intervention.

Outcome following surgery for thoracic outlet syndrome.

INTRODUCTION: the diagnosis of thoracic outlet syndrome (TOS) relies heavily on subjective rather than objective assessment criteria. Subsequently, published results after surgical decompression vary considerably. This study aimed to use a symptom-based patient-directed questionnaire to assess the outcome after decompression for TOS. METHODS: sixty patients who underwent decompression procedures were identified from a prospectively maintained vascular database. Patient records were analysed for details regarding initial presentation, investigation, type of procedure used for decompression and management. Outcome questionnaires were sent to all identified patients to give a patient-based outcome measure. RESULTS: eighty-four per cent of patients responded. In 90% of these patients there was an improvement in symptoms post-surgery with a median follow up of 43 months. The results were not influenced by the procedure or approach used. CONCLUSION: surgery remains an effective tool in the management of TOS. A simple patient-directed questionnaire as used in this study could assist in the standardisation of outcome assessment.

Intravascular brachytherapy: a systematic review of its role in reducing restenosis after endovascular treatment in peripheral arterial disease.

INTRODUCTION: Intravascular brachytherapy (IVBT) utilises the percutaneous insertion of a radioactive source to inhibit myointimal hyperplasia in arteries treated by balloon angioplasty or stenting. A systematic review was performed of trials of IVBT in patients with Peripheral Arterial Disease (PAD). METHODS: Search strategy - the reviewers searched Medline, Embase, the Cochrane Peripheral Vascular Diseases Group trials register, DARE, CCT and NHS EED for clinical studies and trials of adjuvant IVBT in PAD. Two reviewers assessed trial quality independently. RESULTS: Fourteen clinical trials were identified by the search, representing five clinical studies (all allocated D for not randomised) and one randomised controlled trial (allocated A). The randomised trial showed a benefit for IVBT compared with placebo (OR 0.35, 95% CI 0.24-0.53). In the non-randomised studies, 12 month cumulative patency rates ranged from 60-87%. There were few technical complications. In the only report involving IVBT and routine concurrent stent insertion acute thrombosis occurred in 7 (21%) of patients. CONCLUSION: Early reports have confirmed the safety and technical feasibility of IVBT. However, follow-up is too short at present to assess the durability and long-term complications of this new therapeutic option.

Homocysteine lowering interventions for peripheral arterial disease and bypass grafts.

BACKGROUND: Elevated plasma levels of the amino acid homocysteine (hyperhomocysteinaemia) are associated with hardening or blocking of the arteries (atherosclerosis) In addition, there is a poorer prognosis, both in the progression of the disease and outcome after therapy. Treatment to lower homocysteine levels has been shown to be both effective and cheap in healthy volunteers. However, the impact of reducing homocysteine levels on the progression of atherosclerosis and patency of vessels after treatment for atherosclerosis is still unknown and forms the basis for this review. OBJECTIVES: To assess the effects of plasma homocysteine-lowering therapy on the clinical progression of disease in patients with peripheral arterial disease (PAD) and hyperhomocysteinaemia, including, as a subset, those who have undergone surgical or radiological intervention. SEARCH STRATEGY: The reviewers (MH,GS) searched the Cochrane Peripheral Vascular Diseases Group trials register, the Cochrane Controlled trials register (2002, Issue 1), MEDLINE, EMBASE and reference lists of relevant articles. SELECTION CRITERIA: Randomised trials of the treatment of hyperhomocysteinaemia in patients with peripheral arterial disease, before and after surgical or radiological intervention versus no treatment for hyperhomocysteinaemia. DATA COLLECTION AND ANALYSIS: Two reviewers (MH,GS) independently assessed trial quality and extracted data. Information on adverse events was collected from the trials. MAIN RESULTS: There are currently no randomised trials available for analysis. REVIEWER'S CONCLUSIONS: Well constructed trials assessing the impact of the treatment of hyperhomocysteinaemia in patients with peripheral arterial disease are urgently required.

Intravascular brachytherapy for peripheral vascular disease.

BACKGROUND: International treatment of atherosclerotic narrowed and blocked arteries involves either bypassing the blockage using a graft, widening it from the inside with a balloon, a procedure known as percutaneous transluminal angioplasty (PTA), or providing a strut to hold the vessel open, known as a stent. All of these treatments are however limited by the high numbers that fail within a year. Intravascular brachytherapy (IVBT) is the application of radiation directly to the site of vessel narrowing. It is known to inhibit the processes that lead to restenosis (narrowing) of vessels and grafts after treatment. OBJECTIVES: The objective of this review was to assess the efficacy and complications of intravascular brachytherapy on maintaining patency after angioplasty or stent insertion in native vessels or bypass grafts of the iliac or infrainguinal arteries. SEARCH STRATEGY: The reviewers searched the Cochrane Peripheral Vascular Diseases Group Trials Register (last searched 5 July 2002), the Cochrane Controlled Trials Register (last searched Issue 2, 2002), MEDLINE, EMBASE and reference lists of relevant articles. SELECTION CRITERIA: Randomised trials of the use of brachytherapy as an adjunct to the treatment of patients with peripheral arterial diseases (PAD) or stenosed bypass grafts of the iliac or infrainguinal arteries arteries versus the procedure without brachytherapy. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data. Adverse events information was collected from the trials. MAIN RESULTS: One trial was identified which met the inclusion criteria, involving 117 patients, mean age 71 years (43-89). The trial compared PTA versus PTA and IVBT in patients with long-segment de novo or restenotic lesions or occlusions of any length in the femoropopliteal artery. Results were provided at six month follow up in 107 patients (54 PTA alone, 53 PTA+IVBT). The results favoured adjuvant IVBT in preventing restenosis/occlusion with an odds ratio (OR) of 0.35 (95% CI 0.24 to 0.53). Analysis of subgroups showed a significant benefit of IVBT in non-diabetics, OR 0.22 (95% CI 0.07 to 0.69), in those undergoing IVBT in restenotic lesions, OR 0.32 (95% CI 0.10 to 1.01), occlusive lesions, OR 0.19 (95% CI 0.06 to 0.62) and lesions in which the PTA length was greater than 10cm, OR 0.24 (95% CI 0.09 to 0.62). REVIEWER'S CONCLUSIONS: Results from the only trial available would suggest that IVBT is effective at improving the patency of femoropopliteal arteries undergoing PTA in the short-term, particularly in non-diabetics with long occlusions (>10cm).

Homocysteine in myointimal hyperplasia.

INTRODUCTION: homocysteine, a sulphur-containing non-essential amino acid, appears to play a role in the pathophysiology of atherosclerosis. However, its role in myointimal hyperplasia, the cause of almost 30% of failures of interventional therapeutic procedures, is much less clear. METHODS: a review of the published scientific data concerning the role of homocysteine in myointimal hyperplasia was performed using MEDLINE and other on-line databases. Evidence was sought from cell culture experiments, animal models and clinical studies. RESULTS: several clinical studies have recently been published linking plasma homocysteine levels to restenosis in coronary and peripheral arterial disease. However, several contradictory studies also exist making the role of homocysteine unclear. There are currently no published randomised trials. Cell culture and animal model experiments have elucidated several potential mechanisms by which may stimulate myointimal hyperplasia. Possible mechanisms include endothelial cell activation with the enhanced release of inflammatory cytokines and growth factors and a direct effect on vascular smooth muscle cell migration and proliferation. CONCLUSIONS: further studies are required before the true role of homocysteine in the pathogenesis of myointimal hyperplasia can be clearly evaluated. If evidence does confirm a role, the ease with which homocysteine levels can be normalised makes it an attractive alternative therapeutic target for intervention.