Summary of unsuccessful cases through transradial approach
| Stage | Indication | n (%) |
| Diagnostic procedures (n=79) | ||
| I | Radial artery vasospasm | 26 (32.9) |
| Small radial artery diameter | 12 (15.2) | |
| Radial artery dissection | 1 (1.3) | |
| II | Radial artery tortuosity | 12 (15.2) |
| Aberrant subclavian artery | 8 (10.1) | |
| Radial artery loop | 4 (5.1) | |
| Brachial artery loop | 1 (1.3) | |
| Tortuous subclavian artery | 2 (2.5) | |
| III | Inability to select left CCA | 2 (2.5) |
| Inability to select left ICA | 1 (1.3) | |
| Inability to select left VA | 3 (3.8) | |
| Inability to select right ICA | 4 (5.1) | |
| Sheath in the venous system instead of the arterial system | 2 (2.5) | |
| IV | Detachment of distal tip of the catheter (device related) | 1 (1.3) |
| Interventional procedures (n=42) | ||
| I | Radial artery vasospasm | 4 (9.5) |
| Small radial artery diameter | 1 (2.4) | |
| II | Chronic occlusion of brachial artery | 1 (2.4) |
| Aberrant subclavian artery | 4 (9.5) | |
| III | Tortuous aortic arch | 6 (14.3) |
| Inability to select left CCA | 4 (9.5) | |
| Inability to select left ICA | 3 (7.1) | |
| Inability to select left ECA | 1 (2.4) | |
| Inability to select left VA | 2 (4.8) | |
| Inability to select right CCA | 2 (4.8) | |
| Inability to select right ICA | 1 (2.4) | |
| IV | Inability to reach the target lesion | 4 (9.5) |
| Need to use specific devices not compatible with radial access | 8 (19) | |
| Inability to retrieve the distal protection device (device related) | 1 (2.4) | |
CCA, common carotid artery; ECA, external carotid artery; ICA, internal carotid artery; MCA, middle cerebral artery; VA, vertebral artery.