Table 1:
Summary statistics of AVM casesa
| Characteristic | Hemorrhage on Noninvasive Imaging |
Overall (n = 519) | |
|---|---|---|---|
| Nonhemorrhagic (n = 293 [56%]) | Hemorrhagic (n = 226 [44%]) | ||
| Age at diagnosis (yr) | 36.9 ± 17.2 | 33.5 ± 19.0 | 35.4 ± 18.0 |
| Sex | |||
| Female | 155 (53) | 116 (51) | 271 (52) |
| Male | 138 (47) | 110 (49) | 248 (48) |
| Whiteb | |||
| Yes | 170 (58) | 113 (50) | 283 (55) |
| No | 123 (42) | 113 (50) | 236 (45) |
| AVM side | |||
| Right | 135 (46) | 105 (46) | 240 (46) |
| Left | 146 (50) | 105 (46) | 251 (48) |
| Midline | 12 (4) | 16 (7) | 28 (5) |
| Maximum dimension (cm) | 3.28 ± 1.58 | 2.43 ± 1.55 | 2.92 ± 1.62 |
| Venous drainage | |||
| Not exclusively deep | 275 (94) | 163 (72) | 438 (84) |
| Exclusively deep | 18 (6) | 63 (28) | 81 (16) |
| Venous stenosis | |||
| 0%–24% | 125 (43) | 112 (50) | 237 (46) |
| 25%–49% | 54 (18) | 38 (17) | 92 (18) |
| 50%–74% | 73 (25) | 38 (17) | 111 (21) |
| 75%–99% | 34 (12) | 30 (13) | 64 (12) |
| 100% (occlusion) | 7 (2) | 8 (4) | 15 (3) |
| Number of draining veins | |||
| Single | 71 (24%) | 123 (54%) | 194 (37%) |
| Multiple | 222 (76%) | 103 (46%) | 325 (63%) |
| Venous ectasia | |||
| Yes | 170 (58) | 76 (34) | 246 (47) |
| No | 123 (42) | 150 (66) | 273 (53) |
| Venous reflux | |||
| Yes | 105 (36) | 46 (20) | 151 (29) |
| No | 188 (64) | 180 (80) | 368 (71) |
a
Values are No. (%) or mean ± SD.
b
Ethnicity is included as a variable, as other studies have shown statistically significant differences in the rates of AVM hemorrhage in individuals of different ethnic backgrounds.