In-hospital Ischemic Stroke Treated by Mechanical Thrombectomy

Abstract

Objective

We investigated in-hospital stroke (IHS) treated by mechanical thrombectomy in comparison with out-of-hospital stroke (OHS) to clarify the points of concern in IHS at our institution.

Methods

Between September 2015 and June 2018, 19 patients with IHS who underwent mechanical thrombectomy (IHS group) were enrolled, and compared with 154 patients with OHS (OHS group) regarding patient characteristics, technical results, and outcome. In this study, we set the detection time in the IHS group as patient arrival time, termed “Door” in the OHS group.

Results

Cardiology and gastroenterology were the two main admitting departments, including four (21%) patients of IHS group. In all, 15 (79%) patients had atrial fibrillation; however, less than one-third of them was taking anticoagulant drugs at onset. There were only two cases of direct consultation to the stroke specialists, although IHS onset was mainly recognized by nurses. The median age in the IHS group was 81 (interquartile range (IQR), 76–86.5) versus 80 in the OHS group (IQR, 73–85; p = 0.43), and the median initial National Institutes of Health Stroke Scale score was 21 (IQR, 16–23) versus 21 (IQR, 14–26; p = 0.92), respectively. Sex, Alberta Stroke Program Early CT Score, etiology, and occlusion site did not differ between groups. The rate of use of intravenous tissue plasminogen activator (IV-tPA) was 26% in the IHS group versus 49% in the OHS group (p = 0.065). The median time of detection to imaging, detection to needle for IV-tPA, and detection to puncture were 32, 69, and 87 minutes, respectively, in the IHS group, being significantly longer than those in the OHS group (11, 30, and 50 minutes; p <0.01, p <0.01, and p <0.01, respectively). The median time of puncture to reperfusion was 39 minutes, being significantly shorter than that in the OHS group (82 minutes; p <0.01). Successful reperfusion defined as thrombolysis in cerebral infarction (TICI) 2b-3 was obtained in 94.7% of the IHS group versus 83.1% of the OHS group (p = 0.19). A favorable outcome (modified Rankin Scale score 0–2) at 90 days was achieved by 36.8% (IHS) versus 35.1% (OHS) of patients (p = 0.88). The rate of symptomatic procedural complications was 0% (IHS) versus 7.1% (OHS; p = 0.23). The rate of death at 90 days was 15.8% (IHS) versus 12.3% (OHS; p = 0.67).

Conclusion

The times of detection to imaging and of detection to puncture in the IHS group were longer than those in the OHS group; however, patients in the IHS group had shorter reperfusion. The outcome of the IHS group did not differ from that of OHS group. Our study suggests that the time course of treatment should be improved and rapid stroke pathways involved in consultation with the stroke specialists for IHS should be organized.

Introduction

Several randomized controlled trials demonstrated the efficacy of acute-phase thrombectomy for acute-phase main cerebral artery occlusion in 2015.^1–5) These studies suggested that it is important to shorten the interval from onset until recanalization as much as possible to improve the functional prognosis. Thereafter, in the treatment of community-onset (out-of-hospital) cerebral infarction, the establishment of an out-of-hospital system by arrangement of a pre-hospital emergency system, such as prompt, adequate emergency transport, through the education of citizens and ambulance crews, as well as arrangement of an in-hospital system from arrival at the emergency outpatient unit until recanalization, have shortened the time, and a specific efficacy has been obtained. On the other hand, in-hospital cerebral infarction in inpatients is not rare, accounting for 2% to 17% of all stroke patients.⁶⁾ In-hospital cerebral infarction occurs in the presence of a disease requiring admission, and it often develops after invasive treatment or surgery, that is, during the perioperative period; therefore, treatment methods are limited in many cases.⁶⁾ For this reason, many studies reported that the outcome of in-hospital cerebral infarction was less favorable than that of out-of-hospital cerebral infarction, but few studies have examined the therapeutic effects. The current status after the introduction of thrombectomy remains to be clarified.^6–11)

In this study, we investigated patients with in-hospital cerebral infarction who had undergone thrombectomy at our hospital, and clarified the current status of treatment and differences from patients with out-of-hospital cerebral infarction.

Materials and Methods

Of 173 consecutive patients who had undergone acute-phase thrombectomy at Ise Red Cross Hospital (our hospital) between September 2015 and June 2018, the subjects were 19 with in-hospital cerebral infarction. We defined in-hospital cerebral infarction as cerebral infarction that occurred during admission in patients hospitalized with diseases other than cerebral infarction. In these patients, we retrospectively examined the department responsible for the treatment of the primary disease at the onset of in-hospital cerebral infarction, primary disease that required admission, presence of arrhythmia or anticoagulant administration, witness at the time of symptom appearance, and contact flow to stroke specialists. In this study, we defined stroke specialists as specialists in neuroendovascular treatment or physicians experienced in such treatment. Furthermore, the following items were compared between the subjects and 154 controls with out-of-hospital cerebral infarction who had undergone thrombectomy during the same period: age, sex, National Institutes of Health Stroke Scale (NIHSS) score at the time of onset, image assessment, disease type, site of occlusion, presence of intravenous tissue plasminogen activator (IV-tPA), rate of patients with a modified Rankin Scale (mRS) score of 0 to 1 before onset, time course regarding treatment, treatment hours, recanalization rate, symptomatic complications, symptomatic intracranial hemorrhage, and outcome. To compare the time course regarding diagnosis and recanalization treatment between the in-hospital and out-of-hospital cerebral infarction patients, the time of detection for the in-hospital cerebral infarction patients was compared with that of arrival at the emergency room (ER) for the out-of-hospital cerebral infarction patients. Therefore, the time course was classified into an interval from the final onset-free time until in-hospital detection or arrival at the ER, that from in-hospital detection or arrival at the ER until image assessment, that from in-hospital detection or arrival at the ER until tPA administration, that from in-hospital detection or arrival at the ER until arterial puncture, that from arterial puncture until recanalization, that from in-hospital detection or arrival at the ER until recanalization and that from the final onset-free time until recanalization. The treatment hours were classified into four categories based on the time of arterial puncture: weekday daytime (8:30–17:00), weekday night (17:00–24:00), weekday midnight (0:00–8:30), and holidays. For image assessment, the Alberta Stroke Program Early CT Score (ASPECTS) was used. In patients on whom magnetic resonance imaging (MRI) was performed without conducting computed tomography (CT), a full score of 10 points was adopted on diffusion-weighted images. The recanalization rate was assessed using the Thrombolysis in Cerebral Infarction (TICI) score based on cerebral angiographic findings at the completion of thrombectomy. Concerning complications, we investigated procedure-associated symptomatic complications and symptomatic intracranial hemorrhage within 48 hours. The outcome was evaluated based on the mRS scores on discharge and 90 days after treatment. Patients with an mRS score of 0 to 2 were regarded as achieving a favorable outcome. For statistical analysis, we used GraphPad PRISM ver. 6 software (Graphpad Software, Inc., San Diego, CA, USA). The values were compared using the Mann–Whitney U-test and chi-square test. A p value of 0.05 was regarded as significant.

Results

The details of 19 patients with in-hospital cerebral infarction are presented in Table 1. At the onset of cerebral infarction, four patients (21.1%) were hospitalized in the Department of Cardiology, 4 (21.1%) in the Department of Gastroenterology, three (15.8%) in the Department of Gastrointestinal Surgery, two (10.5%) in the Department of Neurosurgery, two (10.5%) in the Department of Thoracic Surgery, two (10.5%) in the Department of Nephrology, one (5.2%) in the Department of Neurology, and one (5.2%) in the Department of Respiratory Medicine. The primary diseases that required admission consisted of malignant tumors in five patients (26.3%), cardiovascular diseases in four (21.1%), and infectious/inflammatory diseases in three (15.8%). There were seven perioperative patients (36.8%), and five had been fasted due to inflammatory/digestive diseases (duplicated patients are present). The disease type was evaluated as cardiogenic embolism in 15 patients (78.9%). Regarding etiological factors other than cardiogenic embolism, atherothrombotic cerebral infarction developed in Case 2, and Trousseau’s syndrome related to malignant tumors may have been etiologically involved in the onset of cerebral infarction in Cases 8 and 19. In Case 17 (after surgery for lung cancer), thrombus formation at the blind end of the pulmonary vein may have led to cerebral embolism. Atrial fibrillation was noted in 15 patients (78.9%), but only four (21.1%) had taken anticoagulants before the time of onset. Anticoagulant therapy was discontinued due to surgery in six (31.6%), and no anticoagulant had been administered to five (26.3%). At the time of onset, symptoms were first confirmed by nurses in 17 patients (89.5%) and by visitors in two (10.5%). Concerning methods to contact a stroke specialist after detection, nurses initially contacted the attending physicians, and the latter contacted stroke specialists for six patients (31.6%). For 11 patients (57.9%), nurses initially contacted the attending physicians, and the latter contacted stroke specialists after CT or MRI. For two patients (10.5%) who developed cerebral infarction in the Department of Neurosurgery, nurses directly contacted stroke specialists.

Table 1. Summary of in-hospital stroke patients.

Case	Age	Sex	Department	Primary disease	Etiology	Arrhythmia	Anticoagulant drugs	Witness
1	94	F	Gastroenterology	Cholangitis	CE	Af	None	Nurse
2	81	F	Gastroenterology	Cholecystitis	ATBI	None	None	Nurse
3	82	M	Cardiology	After ablation for Af	CE	Af	DOAC	Nurse
4	81	M	Cardiology	Cardiac failure	CE	Af	DOAC	Nurse
5	90	M	Neurology	Aspiration pneumonia	CE	Af	Warfarin	Nurse
6	86	F	Cardiology	Renal failure	CE	Af	None	Nurse
7	66	F	Thoracic Surgery	After heart valve replacement	CE	Af	Warfarin	Visitor
8	68	M	Gastroenterology	Gastric cancer chemotherapy	Trousseau	None	None	Visitor
9	67	F	Nephrology	Renal failure	CE	Af	Warfarin	Nurse
10	87	F	Cardiology	Cardiac failure	CE	Af	Discontinuation of warfarin	Nurse
11	65	F	Gastrointestinal Surgery	After pancreatic cancer surgery	CE	Af	Discontinuation of warfarin	Nurse
12	90	F	Gastroenterology	Gastrointestinal bleeding	CE	Af	Discontinuation of warfarin	Nurse
13	80	F	Respiratory Medicine	Diffuse alveolar hemorrhage	CE	Af	Discontinuation of warfarin	Nurse
14	91	F	Neurosurgery	Brain tumor	CE	Af	None	Nurse
15	77	M	Neurosurgery	Before spine surgery	CE	Af	Discontinuation of warfarin	Nurse
16	81	M	Nephrology	Dehydration	CE	Af	None	Nurse
17	75	M	Thoracic Surgery	After lung cancer surgery	Iatrogenic	None	None	Nurse
18	86	M	Gastrointestinal Surgery	After colon cancer surgery	CE	Af	Discontinuation of warfarin	Nurse
19	80	M	Gastrointestinal Surgery	Before colon cancer surgery	Trousseau	None	None	Nurse

Case	NIHSS	ASPECTS	Occlusion site	IV-tPA	LKW to detection time (min)	Detection to picture time (min)	Detection to puncture time (min)	Puncture to reperfusion time (min)	Detection to reperfusion time (min)	TICI grade	mRS at 90 days
1	22	7	MCA (M1)	(-)	480	189	329	27	356	3	6
2	18	NA	BA	(+)	102	65	144	204	348	3	6
3	9	10	MCA (M1)	(-)	60	34	91	79	170	3	0
4	21	10	MCA (M1)	(+)	1	13	74	36	110	3	0
5	18	9	MCA (M1)	(-)	30	15	60	38	98	2b	6
6	20	10	MCA (M1)	(+)	75	44	92	35	127	2b	2
7	4	10	MCA (M2)	(-)	2	35	155	195	350	2b	0
8	24	10	MCA (M1)	(-)	0	11	33	76	109	2b	3
9	22	4	ICA	(-)	0	32	52	72	124	2b	5
10	15	8	MCA (M2)	(-)	145	95	147	79	226	2b	4
11	30	9	ICA	(-)	10	29	71	69	140	3	3
12	29	9	ICA	(-)	0	36	59	18	77	2b	5
13	29	NA	BA	(-)	17	11	49	34	83	2b	0
14	34	10	ICA	(-)	30	32	173	33	206	3	4
15	10	10	ICA	(+)	20	9	149	NA	NA	0	5
16	22	10	MCA (M1)	(+)	70	20	87	36	123	2b	2
17	2	10	MCA (M2)	(-)	5	41	95	68	163	2b	0
18	17	10	MCA (M1)	(-)	15	21	71	29	100	3	4
19	20	10	MCA (M1)	(-)	20	8	56	40	96	2b	4

Af: atrial fibrillation; ASPECTS: Alberta Stroke Program Early CT Score; ATBI: atherothrombotic brain infarction; BA: basilar artery; CE: cardioembolism; DOAC: direct oral anticoagulants; ICA: internal carotid artery; IV-tPA: intravenous tissue plasminogen activator; LKW: last known well; mRS: modified Rankin Scale; MCA: middle cerebral artery; NA: not available; NIHSS: National Institutes of Health Stroke Scale; TICI: thrombolysis in cerebral infarction

The background of patients with in-hospital or out-of-hospital cerebral infarction is shown in Table 2. The median age of patients with in-hospital cerebral infarction was 81 years, and there were nine men (47.3%). The median NIHSS score at the time of onset was 21 and the median ASPECTS was 10. The median age of those with out-of-hospital cerebral infarction was 80 years, and the rate of men was 46.7%. The median NIHSS score at the time of onset was 21 and the median ASPECTS was 10. The disease type was evaluated as cardiogenic cerebral embolism in 77.3% of the patients. There were no significant differences between the two groups. The sites of occlusion consisted of the internal carotid artery in five patients (26.3%), middle cerebral artery (M1) in nine (47.4%), middle cerebral artery (M2) in three (15.8%), and basilar artery in two (10.5%) in the in-hospital onset group, demonstrating no significant differences from the out-of-hospital onset group. IV-tPA was administered to five patients (26.3%) in the in-hospital onset group, and this percentage was lower than that in the out-of-hospital onset group (n = 75, 48.7%). However, there was no significant difference (p = 0.065). The rates of patients with an mRS score of 0 to 1 before onset in the in-hospital and out-of-hospital onset groups were 42.1 and 62.3%, respectively, exhibiting no significant difference. During the study period, there were no “drip & ship” patients in the out-of-hospital onset group.

Table 2. Comparison of baseline patient characteristics between in-hospital stroke and out-of-hospital stroke.

	IHS (n = 19)	OHS (n = 154)	P value
Age, median (IQR)	81 (76–86.5)	80 (73–85)	0.43
Male, no. (%)	9 (47.3%)	72 (46.7%)	0.96
Baseline NIHSS, median (IQR)	21 (16–23)	21 (14–26)	0.92
ASPECTS , median (range)	10 (4–10)	10 (6–10)	0.97
Cardioembolism, no. (%)	15 (78.9%)	119 (77.3%)	0.87
Occlusion site, no. (%)
ICA	5 (26.3%)	38 (24.7%)	0.88
MCA (M1)	9 (47.4%)	61 (39.6%)	0.52
MCA (M2)	3 (15.8%)	35 (22.7%)	0.49
Others*	2 (10.5%)	20 (13.0%)	0.76
Use of IV-tPA, no. (%)	5 (26.3%)	75 (48.7%)	0.065
Prestroke mRS (0–1)	8 (42.1%)	96 (62.3%)	0.089

*Regarding occlusion site, there were 2 basilar artery cases among in-hospital stroke patients and 17 basilar artery cases, and 3 anterior cerebral artery cases among out-of-hospital stroke patients.

ASPECTS: Alberta Stroke Program Early CT Score; ICA: internal carotid artery; IHS: in-hospital stroke; IV-tPA: Intravenous tissue plasminogen activator; MCA: middle cerebral artery; mRS: modified Rankin Scale; NIHSS: National Institutes of Health Stroke Scale; OHS: out-of-hospital stroke

The time course of treatment, treatment hours, and results in the two groups are shown in Table 3. In the in-hospital onset group, the median interval from the final onset-free time until in-hospital detection was 20 minutes, and that from in-hospital detection until imaging was 32 minutes. That from detection until tPA administration was 69 minutes, and that from detection until arterial puncture was 87 minutes. The median interval from arterial puncture until recanalization was 39 minutes. In the out-of-hospital onset group, the median interval from the final onset-free time until ER arrival was 148 minutes; a significantly longer time was required (p <0.01). That from ER arrival until imaging was 11 minutes (p <0.01), that from ER arrival until tPA administration was 30 minutes (p <0.01), and that from ER arrival until arterial puncture was 50 minutes (p <0.01); these intervals were significantly longer in the in-hospital onset group. However, the median interval from arterial puncture until recanalization was significantly shorter in this group (vs. out-of-hospital onset group: 82 minutes, p <0.01). The median intervals from detection or ER arrival until recanalization in the in-hospital and out-of-hospital onset groups were 125.5 and 134 minutes, respectively; there was no significant difference (p = 0.074; Fig. 1). The median intervals from the final onset-free time until recanalization were 162 and 295 minutes, respectively, demonstrating a significant difference (p <0.01). In the in-hospital onset group, the median interval from arterial puncture until guiding catheter insertion was 14.5 minutes, being significantly shorter than that in the out-of-hospital onset group (19 minutes; p <0.05). In the in-hospital onset group, seven patients were treated during working hours on weekdays, four patients during night hours, two patients during midnight hours, and six patients on holidays. In the out-of-hospital onset group, 67 patients were treated during working hours on weekdays, 30 during night hours, 12 during midnight hours, and 45 on holidays. There were no significant differences between the two groups. TICI2B or higher recanalization rates in the in-hospital and out-of-hospital onset groups were 94.7 and 83.1%, respectively, with no significant difference. The complete TICI3 recanalization rates were 36.8 and 36.4%, respectively, with no significant difference. There was no symptomatic complication related to treatment in the in-hospital onset group. Such complications were observed in 11 patients (7.1%) in the out-of-hospital onset group, but there was no significant difference. There was no symptomatic intracranial hemorrhage within 48 hours in the former, whereas it was noted in four patients (2.6%) in the latter. However, there was no significant difference. On discharge, patients with an mRS score of 0 to 2 (favorable outcome) accounted for 36.8% and 30.5% in the in-hospital and out-of-hospital onset groups, respectively. After 90 days, such patients accounted for 36.8% and 35.1%, respectively. There was no significant difference in the outcome between the two groups (Fig. 2). In the in-hospital onset group, the causes of death within 90 days consisted of heart failure in Case 1, septic shock in Case 2 and intestinal necrosis related to superior mesenteric artery thrombosis in Case 5. There was no death related to in-hospital cerebral infarction. Deaths were associated with the primary diseases for which these patients were admitted to other departments. On the other hand, death was directly related to cerebral infarction in six (32%) patients in the out-of-hospital onset group. The mortality rates after 90 days in the in-hospital and out-of-hospital onset groups were 15.8% and 12.3%, respectively, demonstrating no significant difference.

Table 3. Comparison of treatment and clinical outcomes between in-hospital stroke and out-of-hospital stroke.

	IHS (n = 19)	OHS (n = 154)	P value
LKW to detection or door*	20 (2–70)	148 (76–422)	<0.01
Detection or door to picture*	32 (13–41)	11 (7–14)	<0.01
Detection or door to needle*	69 (57–93)	30 (24–40)	<0.01
Detection or door to puncture*	87 (60–146)	50 (40–68)	<0.01
Puncture to reperfusion*	39 (34–75)	82 (56–118)	<0.01
Detection or door to reperfusion*	125.5 (102–197)	134 (100–184)	0.74
LKW to reperfusion*	162 (114–265)	295 (216–591)	<0.01
Time zone of thrombectomy			0.94
Weekday daytime	7 (36.8%)	67 (43.5%)
Weekday semi-night time	4 (21.1%)	30 (19.5%)
Weekday late-night time	2 (10.5%)	12 (7.8%)
Holiday	6 (31.6%)	45 (29.2%)
TICI ≥ 2b no. (%)	18 (94.7%)	128 (83.1%)	0.19
TICI 3 no. (%)	7 (36.8%)	56 (36.4%)	0.97
Symptomatic complication no. (%)	0 (0%)	11 (7.1%)	0.23
Symptomatic parenchymal hemorrhage	0 (0%)	4 (2.6%)	0.48
mRS 0–2 at discharge no. (%)	7 (36.8%)	47 (30.5%)	0.57
mRS 0–2 at 90 days no. (%)	7 (36.8%)	54 (35.1%)	0.88
Death at 90 days no. (%)	3 (15.8%)	19 (12.3%)	0.67

* Median (IQR) time (minutes).

IHS: in-hospital stroke; LKW: last known well; mRS: modified Rankin Scale; OHS: out-of-hospital stroke; TICI: thrombolysis in cerebral infarction

Fig. 1. Time-line of treatment of mechanical thrombectomy between in-hospital and out-of-hospital stroke patients.

Fig. 2. Modified Rankin Scale scores at 90 days between in-hospital and out-of-hospital stroke patients.

Discussion

Previous studies reported that the prognosis of patients with in-hospital cerebral infarction was less favorable than that of those with out-of-hospital cerebral infarction.^6–11) Moradiya et al. found that the mortality rate in in-hospital onset patients was higher than in out-of-hospital onset patients (15.7 vs. 9.6%, respectively), and that the rate of patients who were discharged to home was lower (22.8 vs. 30.0%, respectively).¹¹⁾ The onset of cerebral infarction in the presence of a disease requiring admission may result in severe, complex symptoms. Furthermore, cerebral infarction often develops after invasive treatment or surgery, that is, during the perioperative period, or during treatment for hemorrhagic diseases requiring the discontinuation of antithrombotic drugs. Thrombolytic therapy with IV-tPA may not be indicated. Regarding the diagnosis/treatment process, the diagnosis and treatment of in-hospital cerebral infarction are delayed in comparison with those in out-of-hospital cerebral infarction. This may be because nurses’ awareness of symptoms is delayed in non-stroke-specialized departments and because attending physicians do not recognize the urgency of cerebral infarction treatment, preventing prompt examinations. Furthermore, attending physicians do not promptly consult stroke specialists who are responsible for image assessment and consideration of thrombectomy, and this may play a role in the unfavorable outcome of in-hospital cerebral infarction. As thrombolytic therapy with IV-tPA is not indicated for in-hospital cerebral infarction, mechanical thrombectomy, which has recently been increasingly selected, may improve the outcome, but few studies have examined acute-phase thrombectomy for in-hospital cerebral infarction.^8,12) For effective thrombectomy, a prompt diagnosis/treatment flow from onset until recanalization is necessary. Whether thrombectomy is performed on patients with in-hospital cerebral infarction, as for those with out-of-hospital cerebral infarction, should be investigated to overcome this issue.

In this study, we reported patients with acute-phase in-hospital cerebral infarction who had undergone thrombectomy at our hospital. Cardiogenic cerebral embolism is the most important etiological factor for in-hospital cerebral infarction.^9,13) In this study, atrial fibrillation was also observed in 15 patients, and cardiogenic cerebral embolism was considered to be a main etiological factor. In-hospital cerebral infarction is most common in the Department of Cardiology or Department of Cardiovascular Surgery.¹³⁾ Most patients for whom thrombectomy was indicated in our hospital had been hospitalized in the Department of Cardiology or Department of Gastroenterology. In the Department of Cardiology, many patients have ischemic heart diseases, such as heart failure, atrial fibrillation or myocardial infarction, and the risk of in-hospital cerebral infarction for which thrombectomy is indicated is high. In the Department of Gastroenterology, instructions on fasting during admission or the discontinuation of anticoagulant therapy due to gastrointestinal hemorrhage may cause in-hospital cerebral infarction. It is necessary to share the risk of in-hospital cerebral infarction with these departments and establish an environment for early detection. According to a previous study,⁹⁾ in-hospital cerebral infarction developed during the perioperative period in ≥25% of patients. In this study, perioperative cerebral infarction was noted in seven patients (36.8%). Of these, anticoagulant therapy had been discontinued in ≥50%. The discontinuation or dose reduction of anticoagulants during the perioperative period is unavoidable, but the disadvantages of discontinuation should be presented to patients and it must be carefully conducted after receiving informed consent.

There were no marked differences in background factors between the in-hospital and out-of-hospital cerebral infarction patients. However, in this study, the following points differed from those in a previous randomized controlled trial (RCT): the ages in the two groups exceeded 80 years; the median NIHSS score at the time of onset in each group was 21; and the rates of patients with an mRS score of 0 to 1 before onset in the two groups were low (in-hospital onset group: 42.1%, out-of-hospital onset group: 62.3%).^1–5) As for the time course, the median interval from the final onset-free time until detection in the in-hospital onset group was significantly shorter than that from the final onset-free time until ER arrival in the out-of-hospital onset group. In-hospital onset was detected in the early phase, whereas an interval until ER arrival was required in the out-of-hospital onset group, increasing the time difference. When examining the time course regarding diagnosis and treatment, the intervals from detection until diagnostic imaging or arterial puncture in the in-hospital onset group were significantly longer than those in the out-of-hospital onset group. However, the interval from arterial puncture until recanalization was shorter in the former, and there was no difference in the interval from detection until recanalization. In the in-hospital onset group, longer intervals from detection until diagnostic imaging or arterial puncture were required, possibly because the in-hospital contact system was insufficient and because physicians had not understood the urgency of cerebral infarction treatment, as described below. A short interval from arterial puncture until recanalization was primarily related to a shorter interval until guiding catheter insertion in the in-hospital onset group. In this group, the rate of tPA-treated patients was low, and a procedure to guide a thin catheter for diagnostic imaging when confirming recanalization related to tPA administration was omitted in most patients; this may have led to the shorter interval until guiding catheter insertion. The recanalization rate, incidence of complications, rate of patients with a favorable outcome, and mortality rate were similar to those in the out-of-hospital onset group. Patients with an mRS score of 0 to 2 after 90 days (favorable prognosis) accounted for 36.8% of the in-hospital onset patients and 35.1% of the out-of-hospital onset patients. These percentages were lower than those in previous RCTs.^1–5) This was possibly because the age was more advanced than that in the RCTs and because severe-status patients, including those with low-degree independence before surgery, were included.

In this study, the interval from detection until arterial puncture in the in-hospital onset group was longer than that in the out-of-hospital onset group, but prompt recanalization in the former may have improved the functional prognosis, leading to results similar to those in the latter. However, if a treatment flow from detection until imaging/arterial puncture had been more promptly promoted, the prognosis may have been better. This is an issue to be reviewed in the treatment system for in-hospital cerebral infarction. When investigating individual patients, nurses directly contacted stroke specialists after detection for only two patients. For the other patients hospitalized in other departments, nurses initially contacted the attending physicians, and the latter then contacted stroke specialists promptly or after imaging procedures. A delay in the preparation of an angiography room or calling physicians may have led to a prolonged interval from detection until arterial puncture. If anticoagulant therapy is discontinued during perioperative or fasting periods in patients with atrial fibrillation, the medical staff responsible for treatment, such as the attending physician and nurses, must share the awareness that they are high-risk patients for the onset of cerebral infarction. Therefore, if they present neurological deficits such as motor weakness, acute-phase cerebral infarction should be initially suspected. To evaluate whether therapeutic intervention is possible, a system to promptly contact stroke specialists is necessary. In this study, the rate of nurses was the highest among healthcare professionals who detected symptoms. This was similar to the previous finding that nurses detected symptom appearance in ≥two-thirds of patients with in-hospital onset.⁶⁾ Therefore, to shorten the interval from detection until imaging and that from detection until arterial puncture, a system for nurses to directly contact stroke specialists should be established, and in-hospital educational activities to shorten the interval from detection until the start of treatment must be promoted.

This was a retrospective study involving a small number of patients who had undergone thrombectomy at our hospital. For this reason, there may have been some patients in whom the onset of in-hospital cerebral infarction was overlooked by attending physicians despite the necessity of thrombectomy; the results of this study do not completely reflect the current status at our hospital. Furthermore, we compared the time of detection in the in-hospital onset group with the time of ER arrival in the out-of-hospital onset group, but ward nurses’ preparations had not been made in the former, whereas ER nurses’ preparations had been made upon contact with stroke specialists based on information from the ambulance crew in some cases in the latter. There is a limitation of time comparison between the two groups. However, we confirmed an issue to shorten the interval from detection until the start of treatment, which is important. In the future, it may be necessary to improve the results of treatment for in-hospital cerebral infarction at our hospital through in-hospital educational activities.

Conclusion

We examined the current status of patients with acute-phase in-hospital cerebral infarction who had undergone acute-phase thrombectomy at our hospital. In these patients, the interval until the start of treatment was longer than in those with out-of-hospital cerebral infarction. However, the operative time was shorter and there was no difference in the outcome. In patients with in-hospital cerebral infarction, the outcome may be further improved by establishing an in-hospital system that facilitates prompt intervention by stroke specialists.

Disclosure Statement

We declare no conflicts of interest.