Resumen de Aplicacio clinica de l'angiografia de perfusio a la revascularitzacio de l'arteriopatia obliterant
The endovascular treatment (EVT) of Peripheral Arterial Disease (PAD) is based on angiographic imaging and post-revascularization treatment success is based on the subjective interpretation of this visual assessment. 2D perfusion angiography (PA) is an image- processing software which may allow for the quantification of perfusion. In addition, a simpler anatomic classification system, able to describe the arterial disease burden below the groin, needs to be designed to determine the best therapy for any given patient.(1) The aim of this thesis is to create an objective system to assess the success of EVT based on the quantification of tissue perfusion through PA, capable of accurately predicting the healing probability of ischemic ulcers. Secondly, we seek to describe a classification system of easy application during daily clinical practice that will also facilitate comparison of patients among clinical trials.
The Project was designed as a retrospective cohort study with consecutive patients undergoing EVT at a single specialized center for critical limb ischemia (CLI). The cases were analyzed with PA before and after treatment, and also ranked according to current classification systems (Rutherford, TASC and WIfI) and a new proposed classification: the Abano Terme Score (ATS). Demographic and clinical data were recorded and clinical follow- up was performed (at 1 and 6 months). The PA parameters were Arrival Time (AT), Peak Time (PT), Wash-in Rate, Width, Area Under Curve and Mean Transit Time (MTT). Two cohorts were defined based upon a time to heal of less or longer than 30 days.
From January 2015 to July 2016, PA analysis was performed on 580 consecutive patients that underwent EVT. Among them, 332 met the inclusion criteria to be studied, from which 123 were excluded for ulcer healing analysis (34 because of poor image quality, 50 patients had no ulcer, 20 died and 19 were lost at follow-up). Mean age was 72 years and 67.5% were men; 133 patients had Rutherford 5 and 76 had Rutherford 6 lesions, with similar distribution in both groups. The WIfI risk for amputation was also similar for both groups, and it was low in 24%, moderate in 14% and high in 62%. We found significant differences between groups in the healing time for the following cut-off values of PA parameters: AT>6 seconds and improvement of MTT>1.7 seconds or the MTT>4.1 seconds after the treatment. The ATS, while being a simpler classification than current used system, not only showed a better correlation with parameters such as the transcutaneous pressure of oxygen (TcPO2) and PA; but also demonstrated, in a subsequent analysis, a better correlation with ulcer healing and amputation free-survival in patients with Rutherford 5 lesions.
