Thrombolysis in vascular surgery

Background and aims: Thrombolysis is in common use in the treatment of acute forms of vascular disease. It may be used both systemically and locally, in the latter case through an endovascular approach, socalled catheter-directed thrombolysis. The aims of this thesis were to investigate how thrombolysis affects performance-related outcomes pertaining to vascular patency after thrombolysis, and how it affects patient safety and the development of complications. Methods: Retrospective reviews of patient medical records (all studies) and of data collected from the national stroke and vascular surgery registries (Study II). Study I investigated the outcomes of thrombolysis after infrainguinal bypass graft occlusion in 123 consecutive patients. In Study II, the safety-related outcomes after carotid endarterectomy and stenting (CEA and CAS) were evaluated in 79 patients having undergone systemic thrombolysis for stroke, and this cohort was compared with the 3,998 patients treated by the same methods but without preceding thrombolysis. In Study III, 149 episodes of dialysis access occlusion treated by open surgery or thrombolysis were investigated concerning patency and risks of rethrombosis. Study IV assessed the influence of patient level of care during catheter-directed thrombolysis for limb ischaemia and dialysis access thrombosis on safety-related outcomes, and investigated possible risk factors for patient transfer to a higher level of care. Results: In Study I, technical success of CDT was achieved in 85% of cases with an amputation-free survival of 89% and 75% at one and 12 months. Higher age and acute critical limb ischaemia were adversely associated with amputation-free survival. Synthetic grafts had a tendency toward reduced amputation-free survival. Study II showed a similar stroke and death rate following CEA/CAS for patients having undergone systemic thrombolysis compared with those who had not (2.5% versus 3.8%, P=0.55). There was no significant increase in bleeding complications in the thrombolysis cohort (3.8% versus 3.3%, P=0.79). In Study III, CDT of native and prosthetic dialysis accesses yielded a decreased risk of rethrombosis (HR 0.41; 95% CI 0.04-0.98) and native fistulas exhibited better patency both after CDT and open surgery. The complication rate was 2.7% (infection only; there was no death, stroke, severe bleeding or myocardial infarction). Study IV showed no differences in the rate of complications (including major bleeding, myocardial infarction and stroke) in patients on the general vascular ward compared with those under a higher level of care on the postoperative recovery unit. Cardiac disease was an independent risk factor for patient transfer to a higher level of care. Conclusions: CDT yields good results in terms of technical success and amputation-free survival both in the short and medium term after treatment of infrainguinal bypass graft occlusion. Prior systemic thrombolysis seems not to increase the periprocedural risk of CEA or CAS in patients with symptomatic carotid artery stenosis. CDT reduces the risk of rethrombosis both for native and prosthetic fistulas after access thrombosis even after accounting for adjunctive procedures (undertaken more frequently in those undergoing CDT). Care on a general vascular ward appears safe in the context of CDT. Nonetheless, preexisting cardiac disease was shown to increase the risk of transfer and highlights the importance of appropriate patient selection. Thrombolysis is associated with safe and efficaceous treatment of many groups of vascular surgical patients. However, continuous evaluation of outcomes is required in view of the rapid development of endovascular techniques and devices, and further work should also be done on medical adjunctive management in order to maximise vascular patency after successful thrombolysis