Virtual ankle-brachial index - Can we predict the immediate outcome of femorodistal bypass surgery?

Background/Aim. The best treatment for the occlusion of the largest artery in the thigh is a femorodistal (FD) bypass. Ankle-brachial index (ABI) and multi-detector computed tomographic (MDCT) angiography are the gold standards for diagnosing peripheral arterial occlusive disease. The finite element method can help measure the quantity of blood flow and arterial pressure in the arteries in the leg. The aim of this study was to examine the possibility of using finite element analysis (FEA) method in predicting the outcome of FD bypass surgery. Methods. The research involved 45 patients who were indicated for FD arterial reconstruction from December 1, 2021, to March 31, 2023. MDCT angiography of the arteries of the lower extremities was done pre-operatively and post-operatively in all patients, based on which models were made using the finite element method, for measurement ABI. All patients had their ABI measured pre-operatively and post-operatively using the Doppler ultrasound and sphygmomanometer. Based on the findings of the pre-operative MDCT angiography, a post-operative virtual surgical model was made using the finite element method, for measurement of ABI too. The values of ABI were divided into 5 groups: ABI measured preoperatively (ABI pre-op), ABI measured postperatively (ABI post-op), ABI measured on FEA models based on the MDCT findings [ABI (sim) pre-op], ABI sim post-op, ABI measured on virtual surgery model [ABI sim post-op (virtual)]. The ABI of the models were statistically compared with pre-operative and post-operative measurements done on patients. Results. The values based on the virtual ABI model did not show significant differences compared to the values obtained using Doppler sonography /sphygmomanometer and MDCT angiography (p< 0.001). A strong statistically significant correlation was shown between the virtual ABI and the values obtained by the other two methods (p< 0.001). Conclusion. Virtual simulation based on the MDCT angiography parameters of peripheral blood vessels can be successfully used to predict the immediate outcome of the FD bypass surgery.