## 4 Discussion
Our study followed the previous study design with regard to the process that each participant undertook, first viewing the original DICOM images, followed by the presentation of 3 DPPVMs, and then completing a short questionnaire [18; 24]. Consistent with previous studies, the 3 DPPVMs were scored higher in demonstrating anatomical structures and pathology, which is similar to two reports documenting the value of 3D-printed models in the appreciation of complex anatomy and pathology (congenital heart defects), communication with patients and health professionals, and pre-operative/intra-operative planning. In [PERSON]'s study, 3D-printed models and virtual reality were considered the preferred tools in medical education, while 3D-printed models were ranked as the best communication tool in comparison to other methods [24]. These previous studies mainly focused on one particular disease, namely, congenital heart disease, with the development of personalised models, while our study included four different vascular diseases, thus contributing valuable information to the literature with regard to the clinical application of 3D printing in vascular disease. There is increasing evidence proving the value of using 3D-printed models in the simulation-based training and planning of endovascular procedures. A number of review/systematic review articles have reported promising applications of 3D printing in cardiovascular/vascular diseases [20; 21; 25; 26; 27; 28; 29]. Early reports based on cases or case series showed the potential of using 3D-printed models in the training and planning of endovascular surgical procedures, indicating a paradigm shift [9; 15; 16; 30; 31]. Recent studies have further validated these findings based on analyses of more cases [10; 32; 33]. [PERSON] et al. used patient-specific 3D-printed models to guide on-site physician-modified fenestrated stent grafts in 34 patients with thoracabdominal aortic disease (107 fenestrations). Their results showed that, with aid of 3D-printed templates, fenestrated stent grafts were accurately positioned in all cases, achieving good short-to-mid-term outcomes [10]. The same group further expanded the application of 3D printing technology to 44 cases involving aortic arch aneurysm and dissection, and they used 3D-printed models to guide the fabrication of fenestrated stent grafts. A total of 132 branches were successfully reconstructed with 100% technical success, rapid postoperative recovery, and fewer complications [32]. [PERSON] et al. proved the feasibility of connecting a 3D-printed abdominal aortic aneurysm model to a fluid pump, and they used this approach for vascular surgical trainees to perform EVAR simulation procedures. All 22 EVAR procedures were performed with high fidelity [33]. Unlike these previous reports, our 3D-printed models were based on common vascular diseases and did not include complex aortic disease scenarios. However, our study's findings contribute valuable information to the literature, as we covered a range of vascular diseases rather than focusing on one particular vascular disease. Thus, our results align well with those of previous studies, although further evidence is needed to validate the findings, as well as the inclusion of more cases with peri-operative and post-operative follow-up data. Although our models were printed with soft material, the static nature of the 3 DPPVMs was recognised by some of the participants as one of the limitations that could influence their use in surgical simulation. The lack of surrounding structures was scored as the most limiting factor by most of the participants. Ideally, 3D-printed models should be placed in an environment with surrounding anatomical structures, as shown in a study by [PERSON] et al. [34]. The authors developed a patient-specific 3D-printed vascular anatomy simulator, which was connected to a pumping system simulating an authentic environment during interventional procedures.