Related Experiment Video
Updated: Aug 16, 2026
Predicting Amputation using Local Circulating Mononuclear Progenitor Cells in Angioplasty-treated Patients with Critical Limb Ischemia
Published on: September 22, 2020
Adverse outcome in surgery for chronic leg ischaemia--risk factors and risk prediction when using different
T Troëng1, L Janzon, D Bergqvist
1Department of Surgery, Central Hospital, Karlskrona, Sweden.
Insights
Statistical models for predicting chronic leg ischemia surgery outcomes showed low sensitivity. Risk scores were unreliable for forecasting adverse events in this patient group, indicating limitations in current predictive methods.
Area of Science:
- Vascular Surgery
- Biostatistics
- Health Informatics
Background:
- Chronic leg ischemia poses significant surgical risks.
- Accurate outcome prediction is crucial for patient management and surgical decision-making.
Purpose of the Study:
- To compare logistic regression and an expert system (Assistant Professional) for predicting surgical outcomes in chronic leg ischemia.
- To evaluate the efficacy of risk scores derived from these methods.
Main Methods:
- Analysis of 1635 patients from the Swedvasc registry with chronic leg ischemia.
- Development of risk factor models using 17 variables, including patient health, disease severity, and surgical factors.
- Validation of models using logistic regression and Assistant Professional.
Main Results:
- Both methods demonstrated low sensitivity in predicting adverse outcomes for intermittent and critical ischemia.
- Predictive values for adverse outcomes varied, with Assistant Professional showing higher accuracy in some cases but overall low performance.
Conclusions:
- Risk scores generated by logistic regression and Assistant Professional were not sufficiently sensitive for predicting adverse outcomes in chronic leg ischemia surgery.
- The study suggests that current risk functions may be inadequate for this patient population with the available data.
Objective:
to compare two different statistical methods in predicting the outcome of surgery for chronic leg ischaemia.
Material:
the present study from the Swedvasc registry is based on an inception cohort of 1635 patients with chronic leg ischaemia (intermittent claudication in 609 and critical ischaemia in 1026 patients), who have been followed until 1 year after surgery. Outcome was classified as improved vs. not improved, amputated or dead in claudication and as the intact leg vs. amputation or death in critical ischaemia.
Methods:
logistic regression analysis was compared to the inductive expert system program, Assistant Professional, in the prediction of outcome. Seventy per cent of cases in the data base were used to create a risk factor model including 17 variables registered in Swedvasc. These variables included an assessment of patients overall health status, severity of disease, the surgeon's experience and surgical procedures. This model was then evaluated using the remaining 30% of the patients in the data base.
Results:
a risk score indicating a probability of an adverse outcome exceeding 0.5 was, in patients with intermittent claudication, associated with a sensitivity of 38% using logistic regression and 26% using Assistant Professional. The percentages of correctly predicted adverse outcomes were 29 and 50%, respectively. In patients with critical ischaemia, the sensitivities with the two methods were 68 and 38% and the predictive values 42 and 57%, respectively.
Conclusions:
the risk scores created with the two methods gave low sensitivities. It is concluded that risk functions could not be used to predict an adverse outcome in patients operated on for chronic leg ischaemia with the data set used.