Table 2: Studies comparing dilatation methods for bleeding.
| Study | Intervention | Bleeding |
| Frattini, et al. [18] | One-step vs. Alken | One step lower bleeding |
| Amjadi, et al. [19] | One-step vs. Alken | One step lower bleeding |
| Falahatkar, et al. [20] | One-step vs. Alken | One step lower bleeding |
| Aminsharif, et al. [21] | One-step vs. Alken | One step lower bleeding |
| Ozok, et al. [10] | Alken vs. Amplatz | No statistically significant difference |
| Hijazi, et al. [9] | Alken vs. Amplatz | No statistically significant difference |
| Nalbant, et al. [3] | Amplatz vs. Alken vs. Balloon | No statistically significant difference |
| Frattini, et al. [18] | Balloon vs. Alken | Balloon higher bleeding (statistically significant) |
| Wezel F, et al. [11] | Balloon vs. Alken | Balloon higher bleeding (statistically significant) |
| Lopes T, et al. [4] | Balloon vs. Alken | Balloon higher bleeding (statistically significant) |
| Yamaguchi A, et al. [15] | Balloon vs. Alken | Balloon higher bleeding (statistically significant) |
| Şafak M, et al. [6] | Balloon vs. Amplatz | Balloon lower bleeding (Not statistically significant) |
| Gönen M, et al. [17] | Balloon vs. Amplatz | Balloon lower bleeding (Not statistically significant) |
| Davidoff, et al. [16] | Balloon vs. Amplatz | Balloon lower bleeding (Not statistically significant) |