Surveillance of Peripheral Arterial Bypass Graft.

Jayachander, K (2009) Surveillance of Peripheral Arterial Bypass Graft. Masters thesis, Madras Medical College, Chennai.


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INTRODUCTION : The term graft surveillance refers to periodic evaluation of the grafts by means of tests that may involve special instrumentation, by which an abnormal result, suggest, the presence of pathology .By graft surveillance, we can pick up failing grafts and with corrective measures, patency rates can be improved. The steady decline with time in the patency of vascular grafts mandates a protocol of postoperative surveillance to identify grafts at risk of thrombosis since bypass graft occlusion is associated with significantly morbidity and limb loss . The correction of lesions before graft thrombosis can have a significant impact on long term patency. It is particularly important for vein grafts because most will not maintain patency after thrombectomy. Careful postoperative evaluation of patients especially with infrainguinal grafts over the past decade has clearly demonstrated that factors other than the skill of the surgeon and the completion of satisfactory operative procedure will affect the long term patency of vascular conduits.These factors vary depending on the interval in the follow-up period.Factors adversely affecting 30 day patency are primarily technical in nature and are related to surgical technique.Such factors are best prevented and can often be identified by intraoperative evaluation.In the time period between 1 month and 24 months fibrointimal hyperplasia in a variety of forms is the primary cause of graft failure. Beyond 24 months the disease progression in both the inflow and outflow vessels and the conduit degenerative changes results in graft failure. The importance of graft surveillance has inspired to conduct this study in order to clarify the natural history of graft failure. AIM : To detect the hemodynamically failing and failed grafts regardless of symptoms during the follow up. To analyse the outcome of revision procedures. To study the influence of risk factor on graft survival. 49 CONCLUSION : Graft surveillance programme should be mandatory in all peripheral arterial bypass grafts. Limb salvage rate may be increased by doing intraoperative duplex scan which detects the failing grafts in the operation theatre itself, thereby avoiding the need for second anaesthesia and surgery. The usefulness of duplex scan in improving the assisted primary patency which has been proved by many studies mandates the need for graft surveillance. In view of its non invasiveness, Duplex scan plays a major role in detecting the hemodynamically failing grafts before the patient becomes symptomatic. The sensitivity and specificity of it is comparable with that of the invasive angiogram, hence avoiding the need for it. The dependability of Ankle brachial index increases when it is coupled with clinical examination and color Doppler ultrasound than independently. One should be aggressive in salvaging the autogenous vein grafts as the intraluminal thrombus fixed to the intimal layer disrupts the endothelial function whereas thrombosis of prosthetic grafts is not as detrimental as vein occlusion which may be removed by thrombolysis or thrombectomy. Though the presence of risk factors increases the cardiovascular mortality in these patients during the perioperative period, it does not affect the overall graft patency. In occluded grafts, even though revision procedures are time consuming than simple thrombectomy one should not hesitant to do it to improve the secondary patency. No single approach is appropriate for all patients and thus the interventions must be tailored to the individual. Long term anticoagulation with INR monitoring should be considered for selected group of patients with high risk of graft thrombosis or in those who required revision procedures. Vigilant graft surveillance is essential throughout the life to identify the late lesion and also the future lesion in revised grafts.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Peripheral Arterial Bypass Graft ; Surveillance.
Subjects: MEDICAL > Vascular Surgery
Depositing User: Kambaraman B
Date Deposited: 24 Jul 2017 02:39
Last Modified: 24 Jul 2017 02:40

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