title: Long-term risk of vascular events after peripheral bypass surgery. A cohort study.
abstract: Patients with peripheral arterial disease (PAD) are at high risk of major ischaemic events. Long-term data of all major ischaemic events in PAD patients are scarce and outdated, especially for patients with severe PAD requiring bypass surgery. Our objective was to define their long-term prognosis and develop a prediction model which quantifies this risk up to a decade after surgery. We conducted a retrospective cohort study in patients from the Dutch Bypass Oral anticoagulants or Aspirin (BOA) Study; a multicentre randomised trial comparing oral anticoagulants with aspirin after infrainguinal bypass surgery. The primary outcome was the composite event of non-fatal myocardial infarction, non-fatal ischaemic stroke, major amputation, and vascular death. Cumulative risks were assessed by Kaplan-Meier analysis and independent determinants by multivariable Cox regression models. From 1995 until 2009, 482 patients were followed for a median period of 7.8 years. Follow-up was complete in 94%. Overall 60% of patients experienced a primary outcome event, of which the majority was a vascular death (30%), followed by major amputations (12%). The primary cause of vascular death was a cardiovascular event (29%), whereas the minority was due to complications directly related to PAD (6%). Within five years after bypass surgery vascular death occurred in about a quarter of patients and within 10 years in nearly half of patients. This was double the rate as for non-vascular death. The primary outcome event occurred in over a third and over half of patients in 5 and 10 years after bypass surgery, respectively. From four independent determinants for the primary outcome event: age, diabetes, critical limb ischaemia, and prior vascular interventions, we developed a risk chart, which systematically classifies the 10-year risks of the primary outcome event, ranging from 25% to 85%. This study provided a detailed insight in the course of PAD long after peripheral bypass surgery and enables individual risk assessment of major fatal and non-fatal ischaemic events by means of cumulative incidences and a risk chart.
authors.affiliation: Department of Vascular Surgery, University Medical Center Utrecht, Utrecht, The Netherlands. evhattum@tsz.nl
authors.forename: Eline S
authors.initials: ES
authors.lastname: Van Hattum
authors.forename: Marco J D
authors.initials: MJ
authors.lastname: Tangelder
authors.forename: James A
authors.initials: JA
authors.lastname: Lawson
authors.forename: Frans L
authors.initials: FL
authors.lastname: Moll
authors.forename: Ale
authors.initials: A
authors.lastname: Algra
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000671:Amputation, Surgical / Q000706:statistics & numerical data*; D000925:Anticoagulants / Q000627:therapeutic use; D001241:Aspirin / Q000627:therapeutic use; D019917:Blood Vessel Prosthesis Implantation; D048909:Diabetes Complications / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007383:Intermittent Claudication / Q000188:drug therapy / Q000601:surgery*; D007511:Ischemia / Q000188:drug therapy / Q000601:surgery*; D053208:Kaplan-Meier Estimate; D007866:Leg / Q000098:blood supply* / Q000601:surgery; D008297:Male; D015337:Multicenter Studies as Topic / Q000706:statistics & numerical data*; D009203:Myocardial Infarction / Q000453:epidemiology*; D009426:Netherlands / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology*; D011379:Prognosis; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*; D019851:Thrombophilia / Q000188:drug therapy; D014652:Vascular Diseases / Q000401:mortality*
chemical_list: D000925:Anticoagulants; D001241:Aspirin