Decreasing the time delay for thrombolysis, including intravenous thrombolysis (IVT) with tissue plasminogen activator and intra-arterial thrombectomy (IAT), is critical for decreasing the morbidity and mortality of patients experiencing acute stroke. We aimed to decrease the in-hospital delay for both IVT and IAT through a multidisciplinary approach that is feasible 24 h/day.
We implemented the Stroke Alert Team (SAT) on May 2, 2016, which introduced hospital-initiated ambulance prenotification and reorganized in-hospital processes. We compared the patient characteristics, time for each step of the evaluation and thrombolysis, thrombolysis rate, and post-thrombolysis intracranial hemorrhage from January 2014 to August 2016.
A total of 245 patients received thrombolysis (198 before SAT; 47 after SAT). The median door-to-CT, door-to-MRI, and door-to-laboratory times decreased to 13 min, 37.5 min, and 8 min, respectively, after SAT implementation (
SAT significantly decreased the in-hospital delay for thrombolysis, increased thrombolysis rate, and decreased post-thrombolysis intracranial hemorrhage. Time benefits of SAT were observed for both IVT and IAT and during office hours and after-hours.
Thrombolysis, including intravenous thrombolysis (IVT) with tissue plasminogen activator (tPA) and intra-arterial thrombectomy (IAT), is a proven therapy for patients suffering from acute ischemic stroke [
The current guidelines state that the door-to-IVT time should be within 60 min of hospital arrival [
We aimed to decrease the in-hospital delay for both IVT and IAT during both after-hours and office hours using a multidisciplinary approach. In addition, we investigated whether the reduction in time to thrombolysis was related to increases in the thrombolysis rate and decrease in the post-thrombolysis ICH rate.
Korea has a nationwide, local government-funded emergency medical service (EMS) system. The central EMS dispatch office can be reached on one representative phone number, and then communicates with branch EMS stations that are located closest to callers. However, the EMS does not provide a system by which emergency medical technicians (EMTs) can communicate with the receiving hospitals regarding the care of stroke patients. EMTs usually transport stroke patients to the closest general hospitals. There is no central hospital dedicated to EMS transportation of stroke patients. Therefore, 8 out of 61 EMS stations around Seoul and Gyeonggi-do were in charge of 78% of EMS transportations of stroke patients to our emergency room (ER) between 2014 and 2015.
At our hospital, the evaluation of a stroke, using both computed tomography (CT) and magnetic resonance imaging (MRI) technology, as well as thrombolytic therapies, has been available 24 h/day for over a decade. MRI was used for routine imaging to screen for cases of acute stroke until 2005. Because of concerns of an increasing door-to-imaging time, we adopted a noncontrast CT scan for imaging screening followed by a multimodal MRI for thrombolysis candidates in 2005 [
We aimed to decrease the time to thrombolysis. To achieve this goal, in January 2016, we discussed a new model and organized the Stroke Alert Team (SAT), which was comprised of neurologists, emergency physicians, nurses, laboratory physicians and technicians, radiologists, intervention neuroradiologists, radiology technicians and nurses, and admission officers.
Our plan to decrease the thrombolysis time through prospective SAT activities was accepted as the Asan Medical Center Performance Improvement Project 2016. We prepared the SAT project between January 2016 and April 2016 and it was formally initiated on May 2, 2016. As we announced to hospital government and personnel and 8 branches of EMS stations in advance, our specific goals were as follows: (1) to decrease the median door-to-IVT time to 20 min, and (2) to significantly decrease the median door-to-IAT time from that of the past 2 years. We did not specify numbers for the door-to-IAT time because we could not find any references to previous studies or guidelines. We compared the SAT data with the previous data over the past 2 years to define specific goals for motivating SAT members. Moreover, there were no other changes made to the hospital system, structure, or personnel during this period. The SAT program was operational during both office hours and after-hours.
Details of our workflow for the SAT project are described in the
The stroke onset was considered to be the time at which the patient developed stroke symptoms or when the patient was last known to be without ischemic symptoms in cases of an uncertain onset time [
This study was approved by the institutional review board of the Asan Medical Center. The need for written informed consent from the patients was waived due to the retrospective nature of this study.
We compared the baseline characteristics of patients, time intervals between each step of the evaluation and management, thrombolysis rates, and post-thrombolysis ICH before and after SAT implementation. We used a Pearson’s chi-squared test or Fisher’s exact test for categorical variables and a Student’s t-test or Mann-Whitney U-test for continuous variables, as appropriate. The interobserver agreement for the interpretation of post-thrombolysis ICH was determined by calculating the kappa coefficient for each investigator. In addition, the baseline characteristics of the thrombolysis patients and time to thrombolysis were grouped by year from March 2005 to August 2016 for demonstrating yearly trends. Statistical significance was defined as a two-tailed
A total of 1,715 patients experiencing acute ischemic stroke were admitted to our hospital via the ER between January 2014 and December 2015; 297 patients between January 2016 and April 2016; and 297 patients between May 2016 and August 2016. Between January 1, 2014 and August 31, 2016, 247 out of 2,309 patients received thrombolysis for an initial diagnosis of a stroke. Data from one patient with TIA who received IVT before SAT implementation and one patient whose tPA infusion was discontinued because of the identification of an intracranial aneurysm following SAT implementation were included for further analysis. However, data from two patients with stroke mimics (one patient with conversion disorder before SAT implementation, and the other patient with Bell’s palsy after SAT implementation) who received IVT were excluded for further analysis. Thus, we performed a statistical analysis for 245 patients who received thrombolysis between two time periods: “before SAT” (from January 1, 2014 to May 1, 2016) vs. “after SAT” (from May 2, 2016 to August 31, 2016). Of the 245 patients that were included in this study, demographic features, initial NIHSS, thrombolysis types, time to each step of evaluation and thrombolysis, and post-thrombolysis ICH are presented in
Of the 245 thrombolysis patients, 142 (58.0%) visited our hospital by EMS. Ambulance prenotification was employed in 13 (59.1%) out of 22 EMS-transported thrombolysis patients after SAT implementation. In contrast, we received 37 prenotification calls from EMTs after SAT implementation. The final diagnoses of these 37 cases included stroke and TIA for 25 (67.6%) patients (ischemic stroke: n=20; ICH: n=4; and TIA: n=1). Of 12 nonstroke patients, SAT was activated in seven patients, but not activated in five patients despite prenotification. There were 13 (65%) out of 20 ischemic stroke patients for whom ambulance prenotification was utilized and that subsequently received thrombolysis.
The median onset-to-door time was 101 min and this did not change following SAT implementation (
The median door-to-CT time decreased from 18 min to 13 min after SAT implementation (
The median door-to-IVT time decreased from 46 min (interquartile range [IQR] 36–57 min) to 20.5 min (IQR 15.8–32.5 min) following SAT implementation (
The door-to-CT, door-to-MRI, and door-to-laboratory time did not differ between office hours and after-hours (
For the 47 patients who visited the ER following SAT implementation, the door-to-IVT time in patients with ambulance prenotification (median 15 min; IQR 12–19 min) was shorter than that in patients without ambulance prenotification (median 26 min; IQR 20–36 min;
A total of 198 patients received thrombolysis (IVT only: n=105; IAT only: n=57; IVT plus IAT: n=36) before SAT implementation, and 47 patients who received thrombolysis (IVT only: n=28; IAT only: n=13; IVT plus IAT: n=6) after SAT implementation. The total thrombolysis rate was 9.8% (198/2,012) before SAT implementation and 15.8% (47/297) after SAT implementation. The IVT rate was 7.0% (141/2,012) before SAT implementation and 11.4% (34/297) after SAT implementation. Therefore, the thrombolysis rate increased significantly following SAT implementation (total thrombolysis rate:
After SAT implementation, advance notification messages were sent to the neuroradiology intervention team in 18 cases, and IAT was performed for 15 patients due to confirmation of major vascular occlusion on magnetic resonance angiography. Advance notification group messages were not sent in 29 cases, but IAT was performed after multimodal MRI scans revealed vessel occlusions in only four of these cases (positive predictive value=83.3%; negative predictive value=86.2%).
Out of 198 patients, 25 (12.6%) developed ICH before SAT implementation; of these, nine exhibited neurological deteriorations by four or more NIHSS scores (symptomatic ICH: 4.5%). Out of 47 patients, one (2.1%) developed ICH after SAT implementation, and none experienced neurological deterioration by four or more NIHSS scores (symptomatic ICH: 0%). The ICH rate was decreased after SAT implementation (
We implemented the SAT that was feasible for 24 h/day as a prospective performance improvement initiative to minimize the in-hospital delay for thrombolysis (i.e., IVT and IAT). Since SAT implementation, the median door-to-IVT time decreased from 46 min to 20.5 min, and the median door-to-IAT time decreased from 156 min to 86.5 min. We therefore achieved our pre-specified goals to decrease the time for thrombolysis. The total thrombolysis rate increased from 10% before SAT implementation to 16% after SAT implementation, and the IVT rate increased from 7% before SAT implementation to 11% after SAT implementation. The post-thrombolysis ICH rate decreased from 13% before SAT implementation to 2% after SAT implementation. Thus, SAT activities were potentially beneficial to patients experiencing an acute stroke.
Our prospective project commenced by reviewing the recent data and current status of thrombolysis in our hospital. Based on our recent data, we found that our key measures to be taken were to implement ambulance prenotification and reorganize the in-hospital process. Thus, we introduced ambulance prenotification, updated the thrombolysis protocol, specified time limits for each step, applied POCT, jettisoned unnecessary steps, administered tPA on the CT table, and sent group messages to SAT members for each step. These comprehensive activities and real-time peer reviews were feasible, did not require any changes to the overall hospital structure and manpower, and were effective for each step of the evaluation and management processes.
Our success in decreasing the time delay was likely not accomplished in only 4 months, and long-standing continued efforts to improve the hospital system underlie the current achievements. We previously demonstrated a significant reduction in the door-to-IVT time by changing our MRI screening system to CT-plus-MRI screening in December 2005, and by introducing a computerized physician order entry system for thrombolysis candidates in 2007 [
The SAT was designed to be active 24 h/day, and no differences regarding the door-to-CT/MRI time, door-to-laboratory time, and door-to-IVT time were found between the office hours and after-hours after SAT implementation. However, the door-to-IAT time was longer after-hours than during office hours. Nevertheless, the door-to-IAT time after-hours following SAT implementation was shorter than that during the office hours prior to SAT implementation. Since other variables than the door-to-IAT time and CT-to-IAT time were delayed after-hours, we believe that the majority of these delays were due to the time required for the neuroradiologists to arrive at the hospital at night and on holidays. These findings suggest that interventions including the neuroradiologist’s early involvement in the assessment of thrombolysis candidates are also imperative as typically they do not remain at the hospital after-hours. For this purpose, advance notification provided to the intervention neuroradiologists may be helpful. Neurologist criteria for advance notification exhibited high positive (83%) and negative predictive values (86%) in the present study. However, further studies are required to identify proper methods to further decrease the door-to-IAT time, especially after-hours. Earlier initiation of IAT is associated with decreased mortality and morbidity [
Our study has some limitations that should be noted. First, the main outcomes of this study are the reduction in time to thrombolysis for the most recent 4-month period compared with the previous 28 months. A period of 4 months was sufficient to demonstrate improved temporal profiles, but not long enough to investigate clinical outcomes, such as the 3-month modified Rankin Scale. However, the therapeutic benefit of thrombolysis is the greatest when administered early after a stroke and declines over time. Lower rates of ICH after SAT implementation in this study may reduce patient morbidity and mortality. Our future studies will therefore investigate whether the SAT system can be maintained beyond several months and whether the saved time is related to better clinical outcomes. Second, because the hospital-initiated ambulance prenotification was not supported by the government or central EMS, we were required to contact each satellite EMS station and were only able to introduce prenotification in eight out of the 61 EMS stations. As a result, ambulance prenotification could only be utilized in <60% of the total EMS transportations. Simply using EMS to arrive at the hospital is not sufficient for thrombolysis; however, ambulance prenotification does enhance timely thrombolysis [
Using a multidisciplinary approach, we showed that SAT significantly reduced in-hospital delay for thrombolysis treatment. SAT activity was also related to increased thrombolysis rate and decreased post-thrombolysis ICH. Time benefits of SAT were observed for both IVT and IAT, during both office hours and after-hours. Further studies to investigate whether reduction of inhospital delay is related to better clinical outcomes are needed.
The authors have no financial conflicts of interest.
We are grateful to EMTs, emergency physicians and nurses, neurology residents, radiology fellows, radiology technicians and nurses, laboratory technicians, security guards, office administrators, and neurological intensive care unit nurses.
Supplementary materials related to this article can be found online at
Workflow for the Stroke Alert Team project.
Factors to enhance ambulance prenotification by EMTs
Trends in the total numbers and characteristics of stroke patients who visited the emergency room and those who received thrombolysis between March 2005 and August 2016
Baseline characteristics, time to evaluation, and time to thrombolysis according to the ambulance prenotification
The poster on the face arm speech time scale to educate emergency medical technicians. We created posters on the face arm speech time scale (FAST) scale to distribute to emergency medical technicians and local emergency medical service stations. These posters were posted on each ambulance and emergency medical service station. The Stroke Alert Team (SAT) phone numbers, hospital name, and hospital logo were not shown in the original version of this poster for local legal reasons.
In-hospital delay in administering thrombolysis. The 11-year trends of the median door-to-IVT time (A) and door-to-IAT time (B). Since SAT implementation (May 2, 2016), the median door-to-IVT time decreased to 20.5 min, and the median door-to-IAT time was also decreased to 86.5 min. SAT activities were prepared between January 1, 2016 and May 1, 2016, and implemented between May 2, 2016 and August 31, 2016. Error bars represent medians and 95% confidence intervals. IVT, intravenous thrombolysis; IAT, intra-arterial thrombectomy; SAT, the Stroke Alert Team. *With recombinant tissue plasminogen activator; †Between January 1, 2016 and May 1, 2016 (run-up period); ‡Between May 2, 2016 and August 31, 2016 (after SAT implementation).
Ambulance prenotification utilization in 22 thrombolysis patients who arrived at the hospital by EMS (A). The median door-to-IVT time and door-to-IAT time in 22 patients whose emergency medical technicians utilized ambulance prenotification (B and C). EMS, emergency medical service; IVT, intravenous thrombolysis; IAT, intra-arterial thrombectomy. *With recombinant tissue plasminogen activator.
The process for acute stroke care in the emergency room before and after implementation of SAT
Measures | Before SAT implementation | After SAT implementation |
---|---|---|
Ambulance prenotification | No | Yes |
Education and feedback for EMT | No | Yes |
Hospital registration | Patient or family | Security guard |
Group message | Yes, once on arrival | Yes, on arrival and follow-up on thrombolysis |
First place to move patients | Triage at ER | Resuscitation room at ER |
Blood tests before tPA |
BST, routine labs |
BST, POCT |
tPA kit | Absent | Prepared |
Place to inject tPA | Emergency room | CT |
Person who injects tPA | ER nurse | Neurology resident and fellow |
tPA permission | Written permission before tPA | Verbal permission before tPA |
Written permission after tPA may be waived | ||
Advance notification NRI team and SAT | No | Yes, immediately after CT scan, group message |
Transportation to angiography suite after MRI |
Via ER | Directly to angiography suite |
Prepared IAT set | No | Yes, organized in the angiography suite |
Thrombolysis protocol | Present, outdated | Present, updated, in detail |
Time limit in each step | No | Yes |
Real-time feedback | No | Yes, group message, website |
Regular case review | No | Yes |
SAT, the Stroke Alert Team; EMT, emergency medical technician; ER, emergency room; Routine labs, routine laboratory; tPA, tissue plasminogen activator; BST, finger-prick blood sugar test; POCT, point-of-care tests including prothrombin time, hematocrit, and electrolytes; CT, computed tomography; NRI, neuroradiology intervention; MRI, magnetic resonance imaging; IAT, intra-arterial thrombectomy.
Recombinant tPA;
Including complete blood count, prothrombin time, activated partial thromboplastin time, chemical batteries, and electrolyte batteries;
Noncontrast enhanced CT;
Including diffusion-weighted imaging, fluid-attenuated inversion recovery imaging, gradient-echo imaging, magnetic angiography, and perfusion-weighted imaging.
Baseline characteristics, time to evaluation, time to thrombolysis, and post-thrombolysis intracranial hemorrhage
Before SAT (n=198) | After SAT (n=47) | ||
---|---|---|---|
Age (years) | 68.5 (57.0–76.0) | 68.0 (64.0–74.0) | 0.457 |
Sex, male | 125 (63.1) | 28 (59.6) | 0.651 |
Initial NIHSS | 10.0 (6.0–14.0) | 9.0 (4.0–15.0) | 0.838 |
Ambulance transportation, yes | 120 (60.6) | 22 (46.8) | 0.085 |
Transportation time by EMS (min) | 18.0 (14.0–25.0) | 17.0 (12.5–21.5) | 0.246 |
Stroke onset-to-door (min) | 107.0 (45.5–218.5) | 91.0 (36.0–199.0) | 0.144 |
Door-to-group messaging (min) | 7.0 (5.0–11.0) | 7.0 (3.0–11.75) | 0.261 |
Door-to-CT (min) | 18.0 (15.0–23.0) | 13.0 (8.0–19.0) | <0.001 |
Door-to-MRI (min) | 56.0 (44.5–70.0) | 37.5 (30.3–52.0) | <0.001 |
Door-to-CBC (min) | 43.0 (33.0–59.0) | 40.5 (28.0–59.3) | 0.426 |
Door-to-PT (routine) (min) | 46.0 (37.0–60.0) | 41.0 (33.8–58.5) | 0.089 |
Door-to-PT (POCT) (min) | 46.0 (37.0–60.0) | 8.0 (4.0–29.0) | <0.001 |
Thrombolysis type | |||
IVT |
105 (53.0) | 28 (59.6) | 0.418 |
IAT only | 57 (28.8) | 13 (27.7) | 0.878 |
IVT |
36 (18.2) | 6 (12.8) | 0.376 |
Door-to-IVT |
46.0 (36.0–57.0) | 20.5 (15.8–32.5) | <0.001 |
Door-to-IAT (min) | 156.0 (124.5–212.5) | 86.5 (67.5–102.3) | <0.001 |
Stroke onset-to-IVT |
129.0 (84.3–183.3) | 102.5 (49.0–153.5) | 0.024 |
Stroke onset-to-IAT (min) | 400.0 (215.0–805.0) | 227.5 (153.8–328.5) | 0.002 |
CT-to-IVT |
27.0 (19.0–37.0) | 9.0 (6.0–15.0) | <0.001 |
IVT |
102.0 (83.5–129.0) | 68.0 (65.0–89.0) | 0.073 |
CT-to-MRI (min) | 37.5 (23.8–51.3) | 25.0 (17.0–41.0) | 0.003 |
CT-to-IAT (min) | 134.0 (101.0–167.0) | 82.0 (67.5–119.0) | <0.001 |
MRI-to-IAT (min) | 106.0 (81.5–167.0) | 60.5 (49.5–72.3) | <0.001 |
Intracranial hemorrhage | 26 (13.1) | 2 (4.3) | 0.035 |
Values are expressed as a number (%) or median value (interquartile range).
SAT, the Stroke Alert Team; NIHSS, the NIH Stroke Scale; EMS, emergency medical service; CT, computed tomography; MRI, magnetic resonance imaging; CBC, complete blood count; PT, prothrombin time; POCT, point of care test; IVT, intravenous thrombolysis; IAT, intra-arterial thrombectomy.
With recombinant tissue plasminogen activator.
Baseline characteristics, time to evaluation, time to thrombolysis, and post-thrombolysis intracranial hemorrhage according to the time of hospital arrival following SAT implementation
After-hours (n=30) | Office hours (n=17) | ||
---|---|---|---|
Age (years) | 68.0 (62.0–75.0) | 70.0 (65.0–74.0) | 0.438 |
Sex, male | 15 (50.0) | 13 (76.5) | 0.076 |
Initial NIHSS | 9.0 (4.0–15.0) | 10.0 (4.5–18.0) | 0.478 |
Ambulance transportation, yes | 15 (50.0) | 7 (41.2) | 0.560 |
Ambulance prenotification, yes | 8 (26.7) | 5 (29.4) | 1.000 |
Transportation time by EMS (min) | 16.0 (13.0–21.0) | 20.0 (14.0–25.5) | 0.395 |
Prenotification-to-door (min) | 11.5 (9.3–14.5) | 11.0 (7.5–17.0) | 1.000 |
Stroke onset-to-door (min) | 90.0 (34.8–159.3) | 100.0 (34.0–214.0) | 0.790 |
Door-to-group messaging (min) | 8.0 (3.0–13.5) | 4.5 (2.0–8.5) | 0.173 |
Door-to-CT (min) | 14.0 (8.0–19.3) | 10.0 (7.8–17.5) | 0.585 |
Door-to-MRI (min) | 39.0 (33.0–53.0) | 31.0 (23.0–51.0) | 0.131 |
Door-to-CBC (min) | 49.0 (30.5–59.5) | 37.0 (25.5–57.0) | 0.406 |
Door-to-PT (routine) (min) | 40.0 (32.0–55.0) | 43.0 (39.0–60.5) | 0.127 |
Door-to-PT (POCT) (min) | 8.0 (4.0–26.5) | 9.0 (3.0–42.0) | 0.665 |
Thrombolysis type | |||
IVT |
20 (66.7) | 8 (47.1) | 0.188 |
IAT only | 5 (16.7) | 8 (47.1) | 0.041 |
IVT |
5 (16.7) | 1 (5.9) | 0.396 |
Door-to-IVT |
22.0 (15.5–31.5) | 19.0 (14.5–46.0) | 0.878 |
Door-to-IAT (min) | 100.0 (78.0–154.0) | 72.0 (51.0–89.0) | 0.020 |
Stroke onset-to-IVT |
118.0 (74.5–158.0) | 57.0 (42.5–111.5) | 0.066 |
Stroke onset-to-IAT (min) | 195.0 (147.0–315.0) | 246.0 (148.5–544.5) | 0.603 |
CT-to-IVT |
8.0 (6.0–15.0) | 9.0 (6.3–12.0) | 0.842 |
IVT |
73.0 (63.5–101.3) | 67.0 (67.0–67.0) | 0.857 |
CT-to-MRI (min) | 35.0 (20.3–50.0) | 32.0 (23.0–51.0) | 0.742 |
CT-to-IAT (min) | 135.5 (104.8–167.8) | 99.0 (74.0–143.0) | 0.002 |
MRI-to-IAT (min) | 66.0 (46.5–83.5) | 56.5 (47.0–67.8) | 0.562 |
Intracranial hemorrhage | 2 (6.7) | 0 (0) | 0.528 |
Values are expressed as a number (%) or median value (interquartile range).
SAT, the Stroke Alert Team; NIHSS, the NIH Stroke Scale; EMS, emergency medical service; CT, computed tomography; MRI, magnetic resonance imaging; CBC, complete blood count; PT, prothrombin time; POCT, point of care test; IVT, intravenous thrombolysis; IAT, intra-arterial thrombectomy.
With recombinant tissue plasminogen activator.