Summary
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outdated, especially for patients with severe PAD requiring bypass surgery.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 longterm 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 nonfatal 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.
Keywords
Atherosclerosis - peripheral artery disease - ischaemia - bypass surgery - prognosis