Nurse Practitioner Contribution to Shortening the Time from Angiography Suite Entry to Puncture in Mechanical Thrombectomy for Acute Ischemic Stroke

Abstract

Objective

Minimizing the time to reperfusion is a critical determinant of the prognosis of acute ischemic stroke (AIS). To reduce the workload of neurosurgeons, improve efficiency, and shorten the time required for AIS management delivered by the neurosurgical department, a nurse practitioner (NP) was introduced in April 2019. However, the effect of NP involvement on post-door-to-needle (D2N) intervals, particularly time to reperfusion, has not been clarified. This study examined whether NP participation was associated with shorter post-D2N time metrics in patients with AIS undergoing mechanical thrombectomy (MT).

Methods

This study included all consecutive patients with AIS due to intracranial large vessel occlusion who underwent MT between April 2019 and March 2024 at our institution. Patients with NP involvement were assigned to the NP group, and those without NP involvement were assigned to the non-NP group. NP participation was randomly determined according to their duty schedule. The primary outcomes were the median times from angiography suite entry-to-puncture (E2P) and from suite entry-to-recanalization (E2R). Secondary outcomes included onset-to-puncture (O2P), puncture-to-recanalization (P2R), door-to-entry (D2E), door-to-puncture (D2P), and the proportion of patients with a modified Rankin Scale (mRS) score of 0–2 at discharge. Statistical analyses included univariate and multivariate linear regression analysis, with significance set at p <0.05.

Results

In total, 115 patients were included: 44 in the NP group and 71 in the non-NP group. The baseline patient characteristics were comparable. The median E2P was significantly shorter in the NP group (15 vs. 21 min; p <0.05), representing a 6-min reduction (28.6%). The median E2R was 73 vs. 76.5 min, showing a nonsignificant 3.5-min decrease. Among the secondary metrics, D2P was shorter in the NP group, whereas the O2P, P2R, and D2E levels did not differ significantly. In the multivariate linear regression analyses, only E2P remained independently associated with NP involvement. The proportion of patients with favorable outcomes (mRS 0–2) at discharge was higher in the NP group (27.3% vs. 19.7%), although the difference was not significant.

Conclusion

NP participation significantly reduced E2P time. These findings suggest that NP involvement contributes to shortening the treatment time in the post-D2N phase and may have a crucial role in promoting efficient team-based care in AIS management.

Introduction

The primary therapeutic approaches for acute ischemic stroke (AIS) include intravenous administration of recombinant tissue plasminogen activator (t-PA) and mechanical thrombectomy (MT).^1–5) It has been estimated that for every minute of treatment delay in large-vessel occlusive stroke, approximately 1.9 million neurons are lost.⁶⁾ Clinical outcomes are strongly dependent on the speed of recanalization, with a delay of 1 h associated with a 5.2% reduction in the probability of a favorable outcome.⁷⁾ Accordingly, minimizing the time to reperfusion is a critical prognostic determinant.

Current guidelines recommend a door-to-needle (D2N) time of <60 min.^8,9) Although no specific target time for MT has been clearly defined, previous reports have suggested that arterial puncture should ideally be achieved within 60 min of imaging and the first reperfusion within 90 min.⁴⁾ In Japan, particularly in rural areas, a limited number of physicians are commonly responsible for outpatient care by providing explanations to patients and families, directing nurses and technicians, and subsequently performing procedures. This often results in a prolonged time from hospital arrival to intervention. Similar delays have been observed in our institution. To streamline the AIS workflow, a nurse practitioner (NP) was introduced in our neurosurgical department in April 2019.

The NP profession originated in the United States in the 1960s and has since spread worldwide. In Japan, NP education commenced in 2008, and as of April 2024, 872 NPs have been certified. Japanese NPs are certified after completing graduate-level education and obtaining a society-based credential; however, the qualification remains a professional society certification rather than a national license. Although the final licensure category of NPs is identical to that of registered nurses, institutional regulations allow NPs to perform certain medical procedures—excluding those strictly reserved for physicians—under comprehensive or direct physician supervision. Another distinguishing feature of NPs in Japan is that they are assigned to specific clinical departments and can provide continuous medical and nursing care throughout the patient’s clinical course.

While NPs are widely implemented internationally and have been nationally licensed in many countries, awareness of their role in Japan remains limited, and their integration into the healthcare system is still in an early developmental stage. Therefore, accumulating evidence demonstrating the clinical impact of NPs is essential for future national licensing.

In AIS management, NPs are permitted to perform medical procedures—excluding those strictly reserved for physicians—under comprehensive or direct physician supervision and are able to engage across the entire AIS workflow. This scope of practice differs from that of emergency department and angiography nurses. By preparing procedures and coordinating among multiple disciplines in parallel with physicians, NPs were considered to potentially reduce workflow stagnation and thereby contribute to more rapid reperfusion.

Although previous studies have suggested that NP involvement may shorten the D2N time,^10,11) no reports have specifically focused on the post-D2N processes or examined the extent to which NP participation contributes to reducing the time required to achieve reperfusion.

Therefore, this study aimed to investigate the impact of NP involvement on time reduction within the AIS workflow, with a particular emphasis on the processes that occur after D2N.

To the best of our knowledge, this is the first study to evaluate the influence of NP participation on the post-D2N processes in AIS management.

We hypothesized that, by performing procedural preparation and coordinating multidisciplinary tasks in parallel with physicians, NPs would shorten the post-D2N time, particularly the interval from angiography suite entry to arterial puncture (entry-to-puncture: E2P).

In this study, we conducted a retrospective analysis to evaluate whether NP involvement contributes to shortening the post-D2N time in AIS management.

Materials and Methods

This study included all consecutive patients diagnosed with AIS due to intracranial large-vessel occlusion who underwent MT at our institution between April 2019 and March 2024. Among the patients deemed eligible for MT, those managed with NP participation were assigned to the NP group, while those treated without NP involvement comprised the non-NP group; comparative analyses were subsequently performed. In all cases, NP participation was randomly determined according to the NP schedule. The NP participation was not limited to weekday daytime hours. Although NP involvement did not cover all cases, the NP participated whenever available, including during night shifts, weekends, and holidays.

The NP involved in this study had 5 years of clinical experience in the neurosurgical field as a registered nurse, including 4 years working in a stroke center, where she served concurrently as a ward/special care unit nurse and as a dedicated angiography suite nurse. As a registered nurse, she assisted in more than 100 neuroendovascular procedures and possessed practical knowledge of procedural flow and peri-procedural management in neuroendovascular therapy.

However, she had no experience participating in neuroendovascular procedures as an NP prior to the study period, and her full involvement in neuroendovascular therapy began in April 2019.

All data were obtained from our institution.

During the study period, the average composition of personnel involved in AIS management included 2 neurologists (1 board-certified internist and 1 neurology resident), 2 neurosurgeons (1 board-certified neuroendovascular specialist and 1 neurosurgery resident), 1 emergency department nurse, 1 angiography suite nurse, and 1 radiological technologist. This staffing pattern remained consistent regardless of weekday/weekend or day/night.

As of April 2019, the years of experience of the 2 neuroendovascular neurosurgeons who mainly performed MT were 20 years (5 years as a board-certified supervisory neuroendovascular specialist) and 13 years (3 years as a board-certified neuroendovascular specialist), respectively.

The AIS workflow at our institution was organized such that 2 neurologists managed patients from hospital arrival to imaging, after which 1 board-certified neuroendovascular neurosurgeon assumed responsibility from imaging to reperfusion. A neurosurgery resident joined upon entry to the angiography suite, and the neuroendovascular procedure was performed. The personnel configuration in the angiography suite remained the same regardless of NP involvement, and no additional staff were allocated when the NP participated.

No dedicated AIS team existed; therefore, the emergency department nurse, angiography suite nurse, and radiological technologist responding to AIS cases were those who happened to be on duty at the time.

Initial assessment and intravenous t-PA administration were performed solely by neurologists. Eligibility for MT was determined by either a neurologist or a board-certified neuroendovascular neurosurgeon. In our institution, NPs do not participate in the initial evaluation or t-PA administration. This arrangement does not reflect a surplus of physicians; rather, it is based on institutional regulations that limit NP practice to the neurosurgical domain, allowing NP involvement only after radiological confirmation of large-vessel occlusion. Consequently, NP participation begins after imaging confirmation and is restricted to the post-D2N processes.

Unlike conventional emergency department or angiography nurses, NPs are permitted—under comprehensive or direct physician supervision—to perform certain delegated medical procedures and are able to engage across multiple stages of the AIS workflow rather than at a single point of care.

After radiological confirmation, the NP carried out delegated medication and diagnostic orders, coordinated angiography suite entry with radiology staff, prepared the sterile field and endovascular devices, positioned the patient, maintained sterility, and directly assisted with MT procedures (Fig. 1).

Fig. 1. Workflow of AIS management and roles of healthcare providers. This schematic illustrates the clinical workflow of AIS, from symptom onset to recanalization, including hospital arrival (door), imaging (picture), angiography suite entry (entry), arterial puncture, and final recanalization. The specific roles of each discipline are shown at each step. In contrast to conventional nurses, the NP contributed to multiple post-imaging processes, including entry coordination, preparation of the sterile field and endovascular devices, patient positioning, and procedural assistance during mechanical thrombectomy. The boxes and arrows indicate delegable tasks from neurosurgeons to the NP, which were proactively performed according to clinical conditions and in parallel with physicians’ activities, representing the primary phase of NP involvement in this workflow. Angiography suite staffing was identical between NP and non-NP cases, consisting of 1 operator (neuroendovascular neurosurgeon), 1 assistant (neurosurgery resident or NP), 1 angiography nurse, and 1 radiological technologist. No additional personnel were assigned during NP involvement, and a neurosurgery resident joined the team after angiography suite entry in both groups.

AIS, acute ischemic stroke; ER, emergency room; IC, informed consent; IV, intravenous; IVR, interventional radiology; NP, nurse practitioner; t-PA, tissue plasminogen activator

In addition, whereas device selection and preparation for MT were performed exclusively by physicians before NP implementation, the NP subsequently assumed responsibility for predicting and preparing the appropriate devices based on the anticipated access route and occlusion site after confirming the treatment plan with the physician.

These time-sensitive preparatory and coordinating tasks were performed in parallel with physicians’ responsibilities, such as providing explanations to patients and obtaining informed consent.

Data collected retrospectively included sex, age, stroke location, National Institutes of Health Stroke Scale (NIHSS) score, symptom onset time or last well-known time, arrival time, onset category (in-hospital vs. out-of-hospital), t-PA administration and timing, angiography suite entry time, puncture time, recanalization time, Thrombolysis in Cerebral Infarction grade, stroke subtype, and modified Rankin Scale (mRS) score at discharge.

The Alberta Stroke Program Early CT Score (ASPECTS) was used for anterior circulation occlusion, whereas the Posterior Circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) was used for posterior circulation occlusion. The stroke subtype was classified into large-artery atherosclerosis, cardioembolism, and stroke of other determined or undetermined etiology. The mRS score was assessed by neurologists or neurosurgeons, and poststroke neurological sequelae were determined based on therapists’ documentation. The primary outcomes were the median times from angiography suite entry to arterial puncture (E2P) and from suite entry-to-recanalization (E2R), whereby NP involvement was the most active of all the factors. Secondary outcomes included the median time from onset-to-puncture (O2P), puncture-to-recanalization (P2R), arrival to suite entry (door-to-entry [D2E]), arrival to puncture (door-to-puncture [D2P]), and the proportion of patients with an mRS score of 0–2 at discharge. Univariate analyses were performed for all variables, followed by multivariate linear regression analysis for those showing significant differences. Statistical significance was set at p <0.05. All analyses were conducted using the JMP Student Edition 18.

Ethical approval

This study was approved by the Institutional Review Board of St. Marianna University School of Medicine (approval number: 6910). As this was a retrospective study, an opt-out consent process was implemented and information about the study was disclosed on the hospital website to allow patients the opportunity to decline participation.

Results

During the study period, MT was performed in 115 patients with AIS, of whom 44 were assigned to the NP group and 71 to the non-NP group. No significant differences were observed between the groups with respect to age, sex, in-hospital onset, baseline NIHSS score, ASPECTS or pc-ASPECTS, occlusion site, stroke subtype, t-PA administration, or puncture site (Table 1).

Table 1. Baseline characteristics by NP involvement.

	Total	NP group	Non-NP group	p
N	115	44	71
Age, median (IQR)	81 (73.0–86.0)	81 (73.0–86.0)	79 (72.0–86.0)	0.5095
Female (%)	65 (56.5)	26 (59.1)	39 (54.9)	0.6617
In-hospital stroke (%)	28 (24.4)	13 (29.6)	15 (21.1)	0.3066
NIHSS, median (IQR)	19.5 (14.8–24.0)	19.5 (14.8–24.0)	20.5 (14.3–29.0)	0.6799
ASPECTS or pc-ASPECTS, median (IQR)	8 (6.0–10.0)	8 (6.0–10.0)	8 (6.0–9.0)	0.5005
Occluded vessels				0.3295
ICA (%)	37 (32.2)	10 (22.7)	27 (38.0)
M1 (%)	50 (43.5)	22 (50.0)	28 (39.4)
M2 (%)	19 (16.5)	9 (20.5)	10 (14.8)
BA-VA (%)	9 (7.8)	3 (6.8)	6 (8.5)
Stroke subtype				0.9671
LAA (%)	16 (13.9)	6 (13.6)	10 (14.1)
CE (%)	87 (75.7)	33 (75.0)	54 (76.1)
Stroke of other determined or undetermined etiology (%)	12 (10.4)	5 (11.5)	7 (9.9)
t-PA (%)	30 (26.1)	10 (22.7)	20 (28.2)	0.5183
Angiography suite staffing, n (fixed number of personnel)		5 (including NP)	4	N/A
Approach				0.3996
Arm (%)	39 (33.9)	17 (38.6)	22 (40.0)
Femo (%)	76 (66.1)	27 (61.4)	49 (69.0)

Values are expressed as median (IQR) or number (%).

Arm, radial/upper-arm artery access; ASPECTS, Alberta Stroke Program Early CT Score (for anterior circulation); BA-VA, basilar or vertebral artery; CE, cardioembolism; Femo, femoral artery access; ICA, internal carotid artery; IQR, interquartile range; LAA, large-artery atherosclerosis; M1, first segment of the middle cerebral artery; M2, second segment of the middle cerebral artery; NP, nurse practitioner; t-PA, tissue plasminogen activator; N/A, not available; NIHSS, National Institutes of Health Stroke Scale; pc-ASPECTS, Posterior Circulation Acute Stroke Prognosis Early CT Score

The median E2P time was significantly shorter in the NP group than in the non-NP group (15 vs. 21 min), reflecting a 6-min reduction (p <0.05). The median E2R time was 73 min in the NP group and 76.5 min in the non-NP group, corresponding to a 3.5-min reduction, without significance (Table 2).

Table 2. Time intervals in NP vs. non-NP groups.

Time	NP group	Non-NP group	p
O2P, median (IQR)	216 (157.5–326.8)	237 (166.0–393.0)	0.6168
P2R, median (IQR)	51.5 (35.5–82.5)	48.5 (33.0–71.5)	0.2204
D2E, median (IQR)	87.5 (63.8–134.0)	96 (73.0–131.5)	0.1923
D2P, median (IQR)	99.5 (78.3–153.0)	125.5 (95.0–162.5)	0.0452
E2P, median (IQR)	15 (10.0–20.8)	21 (15.0–30.0)	0.0014
E2R, median (IQR)	73 (53.5–96.5)	76.5 (57.8–93.5)	0.9402

Values are expressed as median (IQR).

D2E, door-to-entry; D2P, door-to-puncture; E2P, entry-to-puncture; E2R, entry-to-recanalization; IQR, interquartile range; NP, nurse practitioner; O2P, onset-to-puncture; P2R, puncture-to-recanalization

Among the secondary metrics, the D2P time showed a notable reduction in the NP group, whereas the O2P, P2R, and D2E times did not differ significantly between the groups. The multivariate linear regression analysis was conducted for outcomes demonstrating significant differences in the univariate analysis (D2P and E2P). Only E2P time remained independently associated with NP involvement (Table 3), whereas no independent association was observed for D2P time (Supplementary Table 1).

Table 3. Multivariate linear regression for E2P.

Variable	E2P estimate	E2P 95% CI	p
t-PA [0]	−0.17	[−0.28, –0.06]	0.0002
NP [0]	0.12	[0.03, 0.22]	0.0142
Af [0]	0.11	[0.01, 0.21]	0.0314
ASPECTS or pc-ASPECTS	−0.03	[−0.07, 0.01]	0.1733

Values are presented as estimates with 95% CIs and p values.

Af, atrial fibrillation; ASPECTS, Alberta Stroke Program Early CT Score (for anterior circulation); CI, confidence interval; E2P, entry-to-puncture; NP, nurse practitioner; pc-ASPECTS, posterior circulation Acute Stroke Prognosis Early CT Score; t-PA, tissue plasminogen activator

The proportion of patients who achieved a favorable functional outcome (mRS score of 0–2) at discharge was 25.5%. Favorable outcomes were observed in 27.3% and 19.7% of patients in the NP and non-NP groups, respectively. Although the NP group demonstrated a 7.6% higher rate of good outcomes, the difference was not significant (Table 4).

Table 4. Angiographic and functional outcomes.

Variable	Total	NP group	Non-NP group	p
TICI 2b/3 (%)	98 (85.2)	36 (81.8)	62 (87.3)	0.4188
mRS 0–2 (%)	26 (22.6)	12 (27.3)	14 (19.7)	0.3466

Angiographic reperfusion status and functional outcomes at discharge in patients with and without NP involvement. Values are expressed as number (%).

mRS, modified Rankin Scale; NP, nurse practitioner; TICI, thrombolysis in cerebral infarction

Discussion

This single-center retrospective cohort study evaluated the impact of incorporating a neurosurgery-dedicated NP into the AIS care team, focusing on treatment time metrics before and after NP involvement.

The findings demonstrated that the median E2P was significantly shorter in the NP group than in the non-NP group (15 vs. 21 min), representing a 28.6% reduction (p <0.05). In contrast, the median E2R did not differ significantly between the groups (73 vs. 76.5 min; p = 0.9402).

Univariate analysis indicated notable time reductions in both the E2P and D2P intervals. However, multivariate linear regression analysis confirmed that NP participation was independently associated only with E2P, whereas no significant association was observed with D2E.

Therefore, NP involvement was particularly effective in reducing the E2P time, the period during which NPs were most actively engaged.

To the best of our knowledge, this is the first study to evaluate the influence of NP participation on post-D2N processes in AIS management.

Previous single-center retrospective studies have reported time savings associated with NP involvement, specifically an 8–10.5-min reduction in D2N time, equivalent to a 14.8% improvement.^11,12) Moreover, several studies have demonstrated that clinical nurse specialists and NPs can accurately identify patients with acute myocardial infarction and facilitate timely treatment, achieving D2N time reductions of 25–33 min or 48.3%–50% improvement.^13–15) Although these studies were conducted in the context of acute myocardial infarction rather than AIS, and their findings cannot be directly generalized, they similarly suggest that NPs may accelerate time-dependent clinical workflows through advanced assessment and coordination capabilities. This concept aligns with the mechanisms observed in the present study.

The proposed mechanisms for these reductions include the ability of the NP to rapidly assess neurological deficits, determine the eligibility for thrombolysis, identify contraindications,¹²⁾ and facilitate communication across the stroke team, allowing concurrent task execution.¹¹⁾

In the present study, the observed reduction in E2P duration can be attributed to 2 primary factors. First, the NP functioned as the first responder within the AIS care, with active involvement ranging from diagnostic imaging to arterial puncture. Second, the NP can perform several key procedural tasks, including patient positioning, sterile field maintenance, device preparation, sheath insertion, and perfusion setup. With advanced knowledge of cerebrovascular anatomy and endovascular devices, the NP optimized patient preparation, selected appropriate tools based on the puncture site and pathology, and assisted in safe arterial access. These changes may have reduced physicians’ routine workloads and minimized procedural delays, thereby allowing radiology and nursing staff to perform their roles more effectively. Such NP-led coordination may have facilitated smoother team operations, explaining the observed time reduction following D2N.

Although the NP did not participate in all AIS cases owing to shift-based scheduling, the NP was involved in the workflow whenever on duty, regardless of weekday, weekend, daytime, or nighttime. Furthermore, no additional personnel were assigned during NP involvement, and the multidisciplinary team composition was identical between NP and non-NP cases. Therefore, the reduction in E2P time observed in this study is unlikely to be explained by differences in staffing levels, but may instead reflect the NP’s ability to perform time-dependent preparatory tasks in parallel with physicians.

Consequently, each team member focused on their respective duties. Under the supervision of the NP, communication among independently functioning sections was streamlined, resulting in improved overall efficiency.

This study had several limitations. First, the analysis was based on data from a single NP assigned to the neurosurgery department of a single institution, limiting the generalizability to other settings with different staffing models or institutional workflows. Second, as mentioned above, the NP was not involved in all AIS cases, and NP participation depended on work shifts; therefore, the possibility of bias related to NP scheduling cannot be completely excluded. Finally, while the study demonstrated a significant reduction in E2P time associated with NP involvement, the NP group did not show a significant improvement in functional outcomes. However, the trend toward better outcomes suggests a potential clinical benefit, with large, future studies being required to confirm these findings.

Conclusion

NP involvement was associated with a significant reduction in the time from angiography suite entry to arterial puncture in patients undergoing MT for AIS. Although neurological outcomes were not significantly different, NP participation may help streamline post-door-to-needle workflows. Further studies are required to clarify the mechanisms underlying these effects and their potential impact on clinical outcomes.

Supplementary Information

Supplementary Table 1

Multivariate linear regression analysis for D2P. Values are presented as regression estimates with 95% confidence intervals (CI) and p-values.

Disclosure Statement

The authors declare that they have no conflicts of interest.