Abstract
Calculation of rupture risk by multivariate analysis.
Stable unruptured aneurysms should be treated conservatively, not with surgical treatment. Reasons why I take this position are listed in the following.
1. If carefully observed with findings from three-dimensional CT combined with endoscopic examination, aneurysms likely or unlikely to be ruptured can be distinguished. The latter do not need surgical operation, as the rupture risk is low.
2. Endovascular surgery is at present in the transition stage, and my clinic would like to introduce an internal neck clipping coil (which we call iCLIP) or stent (iSTENT) (Fig. 2) to patients from now on rather than undergoing the conventional microcoil embolization procedure mainly with GDC. We explain to the patients whose aneurysm is unlikely to rupture, that elective therapy is better. Only after the aneurysm is found to be steadily enlarging and the risk of rupture is high, conventional or the endovascular procedure with the lowest risk at that stage should be selected.
3. The most important thing is to find factors associated with the rupture, enlargement or de novo aneurysm formation. We found these factors can be found by multivariate analysis. Multivariate analysis will disentwine the confounding situation, gradually revealing the true risk factors. Conventional multivariate analysis needs a large number of cases experienced in our clinic, but we conducted a kind of “virtual” multivariate analysis by borrowing data in foreign medical articles. The validity of this procedure is still to be tested, but patients in a small-sized clinic with a small number of unruptured aneurysm cases may understand what kind of risk they have and what to do to lower the risk of rupture. This procedure of working up statistics using “virtual” data has never been done, and I would welcome any discussion to prove its validity.
As stated above, by our “virtual” multivariate analysis, risk prediction of aneurysm rupture became possible, and we concluded that the conservative treatment should be the first choice for the treatment of unruptured aneurysms.
