Between January 2012 and December 2017, 239 consecutive subjects were enrolled in the prospective endovascular-treatment database for AIS. AIS was caused by posterior-circulation occlusion in 72 (31.0%) patients; three subjects were excluded due to a lack of data, and another two subjects were excluded due to having arterial dissections. Following these exclusions, 67 patients were ultimately recruited in the present study, of which 40 patients (59.7%) had favorable outcomes and 27 patients (40.3%) had poor outcomes. Fifty patients with onsets or last-known times to puncture greater than 6 h were defined as late-window patients; among them, 29 patients (58%) achieved favorable outcomes (Fig. 1).
The median age of all including patients was 63 years (interquartile range [IQR], 57–68 years), and the median NIHSS score was 13 (IQR, 10–22). Successful recanalization was achieved in 60/67 patients (89.6%), SICH occurred in 3/67 patients (4.5%), and mortality occurred in 20/67 patients (29.9%) at 90 days following EVT (Fig. 2). Analysis of all enrolled patients (Table 1) showed that the favorable-outcome group had a prevalence of smoking (42.5% vs. 18.5%; p = 0.04) and intracranial atherosclerosis (ICAS, 62.5% vs. 37%; p = 0.041) compared to those of the poor-outcome group. There was a lower NIHSS score (p = 0.003), lower PMI (p = 0.003), and higher GCS score (p = 0.000) at the time of admission in the favorable-outcome group. However, there were no significant differences in any other risk factors, including stroke, the location of the occlusion, collateral status, anesthesia, rescue therapies, procedural complications, revascularization, or SICH (p > 0.05). In univariate analysis of late-window patients, younger age, lower NIHSS, lower PMI, higher GCS, and complications with ICAS were associated with favorable outcomes (Table 2).
Table 1
Baseline, Procedural, and Outcome Parameters in All Patients
Variables | Total | Favorable outcome (mRS, 0–3) | Poor outcome (mRS, 4–6) | P Value |
N | 67 | 40(59.7) | 27(40.3) | |
Age (IQR) | 63(57–68) | 61(53.25–65.75) | 65(58–72) | 0.029 |
Male (%) | 44(65.7) | 30(75) | 14(51.9) | 0.050 |
Prior or current smoking (%) | 22(32.8) | 17(42.5) | 5(18.5) | 0.040 |
Hypertension (%) | 39(58.2) | 23(57.5) | 16(59.3) | 0.886 |
Diabetes (%) | 12(17.9) | 7(17.5) | 5(18.5) | 0.915 |
Hyperlipidemia (%) | 13(19.4) | 6(15) | 7(25.9) | 0.267 |
Coronary heart disease (%) | 9(113.4) | 5(12.5) | 4(14.8) | 0.785 |
Atrial fibrillation (%) | 11(16.4) | 7(17.5) | 4(14.8) | 0.771 |
Previous stroke or TIA (%) | 19(28.4) | 10(25) | 9(33.3) | 0.458 |
Baseline NIHSS (IQR) | 13(10–22) | 12.5(8.25-17) | 19(13–29) | 0.003 |
Baseline GCS (IQR) | 14(7–15) | 15(13–15) | 10(6–13) | 0.000 |
Pc-ASPECTS (IQR) | 8(6–8) | 8(6–8) | 7(6–8) | 0.319 |
Pons midbrain index (IQR) | 2(1–3) | 1(0–2) | 2(1–3) | 0.003 |
Pretreatment IV tPA (%) | 11(16.4) | 7(17.5) | 4(14.8) | 0.771 |
Anesthetic (%) | | | | 0.061 |
Local anesthesia | 64(95.5) | 40(100) | 24(88.9) | |
General anesthesia | 3(4.5) | 0(0) | 3(11.1) | |
Location of occlusion | | | | 0.119 |
BA (%) | 29(43.3) | 16(40) | 13(48.1) | |
VA (%) | 6(9) | 6(15) | 0(0) | |
Tandem (%) | 32(47.8) | 18(45) | 14(51.9) | |
ASITN/SIR (IQR) | 0(0–1) | 0(0-1.75) | 0(0–1) | 0.375 |
Rescue therapy (%) | 40(59.7) | 26(65) | 14(51.9) | 0.282 |
Stent retriever detachment | 9(13.4) | 6(15) | 3(11.1) | 0.647 |
Other stents | 24(35.8) | 17(42.5) | 7(25.9) | 0.165 |
Balloon expansion | 29(43.3) | 20(50) | 9(33) | 0.177 |
Intra-arterial thrombolysis | 11(16.4) | | | |
With ICAS (%) | 35(52.2) | 25(62.5) | 10(37) | 0.041 |
Successful recanalization (mTICI 2b-3, %) | 60(89.6) | 37(92.5) | 23(85.2) | 0.427 |
Number of Stent retriever passes (IQR) | 1(1–2) | 1(1–2) | 2(1–2) | 0.396 |
Procedural complications (%) | 15(22.4) | 8(20) | 7(25.9) | 0.568 |
Distal embolism | 5(7.5) | 3(7.7) | 2(7.4) | |
Vessel perforation | 3(4.5) | 0(0) | 3(10.7) | |
Stent thrombosis | 4(5.9) | 2(5.1) | 2(7.1) | |
Dissection | 3(4.5) | 2(5.1) | 1(3.6) | |
Vasospasm | 1(1.5) | 0(0) | 1(3.6) | |
Onset to door time (IQR) | 390(215–669) | 355.5(174–660) | 410(231–744) | 0.462 |
Late-window (6–24 h, IQR) | 50(74.6) | 29(72.5) | 21(77.8) | 0.626 |
Door to puncture time (IQR) | 142(90–233) | 145(89–239) | 131(87–208) | 0.483 |
Puncture to first reperfusion time (IQR) | 55(41-80.5) | 55(42–81) | 55(40.5–81.5) | 0.794 |
Puncture to final reperfusion time (IQR) | 96.5(63-137.75) | 88(71–127) | 116(58-158.5) | 0.596 |
Onset to first reperfusion time (IQR) | 582.5(392.25-1082.25) | 575(391–1035) | 652(424.5–1150) | 0.858 |
Onset to final reperfusion time (IQR) | 649.5(462.25-1103.75) | 643(446–1100) | 668(473–1159) | 0.810 |
sICH (%) | 3(4.5) | 1(2.5) | 2(7.4) | 0.560 |
ICH (%) | 7(10.4) | 2(5) | 5(18.5) | 0.108 |
Table 2
Baseline, Procedural, and Outcome Parameters in late-window
Variables | Total | Favorable outcome (mRS, 0–3) | Poor outcome (mRS, 4–6) | P Value |
N | 50 | 29(58) | 21(42) | |
Age (IQR) | 61(54.75-67) | 59(51–65) | 65(59-72.5) | 0.005 |
Male (%) | 33(66) | 22(75.9) | 11(52.4) | 0.084 |
Prior or current smoking (%) | 17(34) | 12(41.4) | 5(23.8) | 0.196 |
Hypertension (%) | 28(56) | 15(51.7) | 13(61.9) | 0.474 |
Diabetes (%) | 7(14) | 4(13.8) | 3(14.3) | 1.000 |
Hyperlipidemia (%) | 11(22) | 6(20.7) | 5(23.8) | 0.793 |
Coronary heart disease (%) | 6(12) | 2(6.9) | 4(19) | 0.223 |
Atrial fibrillation (%) | 9(18) | 5(17.2) | 4(19) | 0.870 |
Previous stroke or TIA (%) | 11(22) | 6(20.7) | 5(23.8) | 0.793 |
Baseline NIHSS (IQR) | 13(9-19.25) | 12(7.5–17) | 18(10.5–23) | 0.015 |
Baseline GCS (IQR) | 14(7–15) | 15(13.5–15) | 10(6.5–14) | 0.004 |
Pc-ASPECTS (IQR) | 7(6–8) | 7(6–8) | 7(6–8) | 0.984 |
Pons midbrain index (IQR) | 2(1–3) | 1(0–2) | 2(1–3) | 0.019 |
Pretreatment IV tPA (%) | 8(16) | 4(13.8) | 4(19) | 0.706 |
Anesthetic (%) | | | | 0.068 |
Local anesthesia | 47(94) | 29(100) | 18(85.7) | |
General anesthesia | 3(6) | 0 | 3(14.3) | |
Location of occlusion | | | | 0.145 |
BA (%) | 21(42) | 10(34.5) | 11(52.4) | |
VA (%) | 4(8) | 4(13.8) | 0 | |
Tandem (%) | 25(50) | 15(51.7) | 10(47.6) | |
ASITN/SIR (IQR) | 0(0–1) | 0(0–2) | 0(0–1) | |
Rescue therapy (%) | 30(60) | 19(65.5) | 11(52.4) | 0.349 |
Stent retriever detachment | 7(14) | 5(17.2) | 2(9.5) | |
Other stents | 19(38) | 15(51.7) | 4(19) | |
Balloon expansion | 23(46) | 14(48.3) | 9(42.9) | |
Intra-arterial thrombolysis | | | | |
With ICAS (%) | 26(52) | 19(65.5) | 7(33.3) | 0.025 |
Successful recanalization (mTICI 2b-3, %) | 45(90) | 27(93.1) | 18(85.7) | 0.638 |
Number of Stent retriever passes (IQR) | 1.5(1–2) | 1(1–2) | 2(1–2) | 0.544 |
Procedural complications (%) | 12(24) | 6(20.7) | 6(28.6) | 0.520 |
Distal embolism | 3(6) | 1(3.4) | 2(9.5) | |
Vessel perforation | 2(4) | 0(0) | 2(9.5) | |
Stent thrombosis | 2(4) | 2(6.9) | 0(0) | |
Dissection | 3(6) | 3(10.3) | 0(0) | |
Vasospasm | 1(2) | 0 | 1(4.8) | |
Onset to door time (IQR) | 450(313-950.75) | 420(309–865) | 470(318-997.50) | 0.680 |
Door to puncture time (IQR) | 177(107–240) | 195(107.5-296.5) | 176(94–213) | 0.487 |
Puncture to first reperfusion time (IQR) | 56(42–84) | 60.5(42-83.5) | 55(40–99) | 0.803 |
Puncture to final reperfusion time (IQR) | 89(63–137) | 84(73.5-116.25) | 124(59–158) | 0.448 |
Onset to first reperfusion time (IQR) | 756(565–1307) | 756(565.5-1318.25) | 753(564–1299) | 0.914 |
Onset to final reperfusion time (IQR) | 781(598–1336) | 784(607.25–1372) | 781(593–1299) | 0.965 |
sICH (%) | 3(6) | 1(3.4) | 2(9.5) | 0.565 |
ICH (%) | 6(12) | 2(6.9) | 4(19) | 0.223 |
In the multivariate logistic regression analysis adjusted for males, smoking, NIHSS, and underlying ICAS among all patients, the following three factors were independently correlated with favorable outcomes at three months following EVT: age (OR 0.914, 95% CI: 0.849 to 0.984; p = 0.017), baseline GCS score (OR 1.234, 95% CI: 1.061 to 1.435; p = 0.006) and PMI (OR 0.448, 95% CI: 0.252 to 0.798; p = 0.006). After adjustments for confounding factors in late-window patients, only age (OR 0.879, 95% CI: 0.799 to 0.967; p = 0.008) was associated with favorable outcomes following EVT. Additionally, NIHSS score (OR 0.914, 95% CI: 0.835 to 1.001; p = 0.054) and PMI (OR 0.533, 95% CI: 0.277 to 1.023; p = 0.0059) each independently correlated with favorable outcomes in late-window patients (Table 3).
Table 3
Logistic regression analysis for favorable outcome
| All patients (n = 67) | Late window (n = 50) |
| OR | 95% CI | P Value | OR | 95% CI | P Value |
Age | 0.914 | 0.849–0.984 | 0.017 | 0.879 | 0.799–0.967 | 0.008 |
Baseline GCS | 1.234 | 1.061–1.435 | 0.006 | | | |
Pons midbrain index | 0.448 | 0.252–0.798 | 0.006 | 0.533 | 0.277–1.023 | 0.059 |
Baseline NIHSS | | | | 0.914 | 0.835–1.001 | 0.054 |