**6. Discussion**

Figure 20 shows how to illustrate this process using our system. First, the user inputs a CAG table, as shown in Figure 20 (a). With our system, the user can set the type of the corre‐ sponding stenosis, as shown in the CAG table. The system then automatically generates a graphical coronary schema, as shown in Figure 20 (b). Figure 20 (c) shows the result of set‐

The bypass connects an open vessel to the closed coronary artery, and the system automati‐ cally opens the closed coronary artery to indicate that blood flow is recovered, as shown in

`A male patient (40 years of age), had suffered from generalized atherosclerosis. (…) During the operation calcification

and complete occlusion of the initial portion of both branches of the left coronary artery were found. An end-to-end

Figure 21 shows how to illustrate this process using our system. First, the user inputs a CAG table, as shown in Figure 21 (a). The system then automatically generates a graphical coro‐ nary schema, as shown in Figure 21 (b). By default, the system automatically generates the stenosis in the middle portion of the corresponding vessel, as shown in Figure 21 (b). The user can move the stenosis to the initial portion, as shown in Figure 21 (c). Figure 21 (d)

The bypass connects an open vessel to the closed coronary artery, and the system automati‐ cally opens the closed coronary artery to indicate that blood flow is recovered, as shown in

The second example is Case 3 of the report [14]. The paper describes it as follows:

ting the severity of a stenosis of the left coronary artery to 100%.

anastomosis between the inner thoracic and interventricular arteries was made.'

**Figure 21.** Case 3 of the report [14] using our system.

Figure 21 (e, f) and (g, h).

shows the result of setting the severity of the stenosis to 100%.

Figure 20 (d, e).

380 Artery Bypass

Our current implementation is a research prototype and is not yet being used in clinical practice. However, we have already demonstrated it to medical professionals and confirmed the following benefits:


In addition, we received the following comment from another heart surgeon: `This is a userfriendly system. It is particularly effective for inexperienced doctors. Diagnosis is performed by a heart physician. But, I think that it is useful also for a young surgeon's training. '

The correspondence between a diagnosis and a dissection, as well as comparison be‐ tween the diagnosis and a CT scan image, are important to a surgeonpreparing for an operation. However, even though there is an AHA standard that defines how to verbal‐ ize diagnosis results, there is significant variation in the way surgeons describe diagnosis results, even among experts. Accordingly, one specialist commented that it is useful to have a link between CT scan images of the circumflex branches to the corresponding lo‐ cations in the schema. The specialist also commented that two-dimensional (2D) repre‐ sentation is sufficient if the purpose of the target system is diagnosis, but 3D representation is desirable for training purposes.

An issue with the current implementation is that it is limited by the AHA standards. The manner of recording schemas for cardiac catheterization varies widely among users and fa‐ cilities. As the AHA committee report was designed more than 30 years ago, it cannot han‐ dle many cases well. Therefore, a more powerful and flexible representation is needed.
