mechanical thrombectomy in improving stroke...

Running head: IMPROVING STROKE OUTCOME 1

Mechanical Thrombectomy in Improving Stroke Outcomes

A Scholarly Project Presented to

The Faculty of the Maryville University

Catherine McAuley School of Nursing

In Fulfillment of the Requirements

For the Degree of Doctor of Nursing Practice

Taryn Denezpi

Spring 2019

Author Note

No grant or funding was needed for this scholarly project.

IMPROVING STROKE OUTCOME 2

Table of Contents

Title Page 1

Table of Contents 2-3

Abstract 4

Chapter I: Introduction 5

Purpose and Specific Aims 6

Background and PICO Question 6-7

Significance 7-8

Practice Support for Project 8-9

Benefit of Project to Practice 9

Chapter II: Synthesis of Evidence 10

Integrated Review of Literature 10-12

Literature Critique 13-15

Concepts and Definitions 15-16

Theoretic Framework 15-16

Chapter III: Project Design and Methodology 16-17

Analysis 17-18

Resources 18

Budget and Timeline 19

Protection of Human Subjects 19

Chapter IV: Findings 20-21

Interpretation of Findings 21-23

Chapter V: Discussion 23-24


Limitations 24

Implications of Findings and Recommendations 24-25

Conclusion 25

References 26-27

Appendix A: table 1 28

Appendix B: Figure 1 29


Abstract

The study was developed to identify if ischemic stroke patients’ ineligible for tissue plasminogen

activator (tPA) experienced an improved outcome post thrombectomy intervention as evidenced

by using the National Institutes of Health Stroke Scale (NIHSS). Methods: A randomized

retrospective chart review including 100 cases of ischemic stroke patients’ ineligible for tPA who

received mechanical thrombectomy within a large comprehensive stroke center. Use of a paired

samples t-test was utilized when analyzing pre-and-post thrombectomy NIHSS. Results: Post-

thrombectomy NIHSS scores decreased by 9 points, indicating an overall improved outcome.

Conclusion: The research demonstrates strong support for the use of thrombectomy in patients’

ineligible for tPA administration.

Keywords: (mechanical) thrombectomy, tPA ineligible, ischemic stroke


Mechanical Thrombectomy in Improving Stroke Outcomes

Introduction

Experiencing a stroke can happen quickly, in just minutes to hours and can often leave

deficits that last a lifetime. According to Casey (2018), a stroke occurs when the flow of blood is

blocked or occluded by plaque or thrombus, resulting in brain tissue death. Usually, 82-92

percent of strokes are considered ischemic in nature, meaning that an artery became blocked in

the brain by a thromboembolic event (Casey, 2018). Reperfusion whether with tPA or with

mechanical thrombectomy after a stoke is essential to stroke survival and outcome improvement

(Casey, 2018). Gautheron et al. (2018) concluded that patients with large diffusion-weighted

imaging lesions such as a devastating M1vessel occlusion, highly benefit from reperfusion

therapy. Fischer et al. (2018) implies that administration of tissue plasminogen activator (tPA)

may not completely lyse thrombi that can be retrieved via mechanical recanalization.

The incidence of stroke is rising but survival rates are similarly on the rise due to early

intervention (Casey, 2018). Since most strokes are ischemic, it is vital that the healthcare

providers recognize the signs and symptoms and distinguish between them so that early

thrombolysis therapy or intervention can take place (Casey, 2018). The decision and action of

intervention is entirely in the hands of the provider, meaning that the survival and recovery after

an ischemic stroke weighs heavily on the provider’s choice of intervention or treatment.

Therefore, knowing all intervention possibilities and associated patient outcomes has become

essential to every stroke victims care. By identifying patients eligible for early thrombectomy,

perhaps a new standard of care can be utilized for ischemic stroke patients that are ineligible for

tPA administration.


Purpose and specific aims

General interest involves the stroke population and the interventions that are used to

prevent and treat strokes. The fact that the world of Neuroscience is ever changing and evolving

for the betterment of each stroke victim, is utterly fascinating. Personal experience as a charge

nurse in a Neurosurgical Intensive Care unit and a rapid Code Neuro Nurse respondent in a

Comprehensive Stroke Center, demonstrated a delay of intervention could lead to lethal

outcomes during an ischemic stroke, therefore quick reperfusion has become essential. Whether

clinicians are attempting to cease brain injury and cell death that occurs during an ischemic

stroke or give the patient a better chance of rehabilitation and outcome, prompt intervention with

either tPA or thrombectomy is now the new standard of care. In the Nurse Practitioner role, it

would be beneficial to understand which intervention is most effective in improving the outcome

of ischemic strokes. Unfortunately, the gold standard of tPA administration has become the

primary standard in ischemic stroke care, with thrombectomy being underutilized in several

areas throughout the United States. If the practice of thrombectomy can be distinguished as

equally beneficial to patient care and outcome, perhaps more healthcare centers will adapt this

intervention to improve overall stroke care practice for those who are ineligible to receive tPA.

Background and PICO question

To begin constructing a literature review a question of interest must be asked about a

specific topic (Melnyk & Fineout-Overholt, 2015). Thus, the PICO (population, intervention,

comparison, outcome) question was, among patients who have experienced an ischemic stroke

and are ineligible for tPA, does mechanical thrombectomy alone in intervention improve patient

outcome as evidenced by National Institutes of Health Stroke Scale (NIHSS)? The population

are patients who have experience an ischemic stroke and are ineligible for tPA, an intervention of


mechanical thrombectomy alone in treatment, with an overall outcome of improving ischemic

strokes by evidence of NIHSS. After developing the PICO question, a web based search for peer

reviewed articles was completed to assist in answering the question through a review of

literature. Maryville University’s online library data base was utilized to find all articles. Search

terms such as stroke, tissue plasminogen activator, and thrombectomy were utilized to filter full

text articles published within the last four years that were peer reviewed. Overall, all articles

supported evidence that mechanical thrombectomy is beneficial in treating ischemic stroke in

combination with tPA. There were fifteen articles of interest found for consideration. Of which,

six became primary resource articles that were reviewed for the purpose of answering the PICO

question and review of literature.

Significance

Nursing and Advanced Practice Provider

Patient safety and advocacy are the most important duties of health care professionals.

Therefore, it is apparent that nurses, Nurse Practitioners and clinicians are aware of what

intervention will be most beneficial to their patient population while inflicting the least amount

of harm possible. Through the use of evidence based research review of new stroke

interventions, health care providers can identify adverse reactions, lethal outcomes, and best

overall stroke intervention outcomes compared to existing treatments such as administration of

tissue plasminogen activator (tPA). Finally, since intervention is the only way to save ischemic

penumbra, it becomes the duty of the clinical Nurse Practitioner and neurologist to decide which

intervention is most appropriate and beneficial to the patient’s outcome and general well-being

(Liu, Zhang & Hong, 2016).


Healthcare. The motivation for this study topic selection is the lack of thrombectomy use

in my current practice environment. In New Mexico, nurse practitioners are granted a wide array

of practice privileges and are used broadly in the emergency departments to care for acute

patients. When a stroke patient arrives, nurse practitioners initiate stroke protocols and consult

neurology to collaboratively work with the neurologist to determine appropriate treatment plans.

This often includes the decision of whether to administer tPA. At this time, there is limited use of

thrombectomy for ischemic stroke treatment within the city. Now that the results of the project

were found, I have presented the results to the stoke coordinator, neurologist and emergency

personnel to advance the knowledge of thrombectomy use. The stroke coordinator and

neurologist have been following the project and are planning to share the results with the

emergency department. Since the results are in favor of thrombectomy the stroke team advised

the administrator and pushed for the intervention to be used within the hospital. The facility has

just completed their first thrombectomy for acute ischemic stroke following results and

encouragement from the project and neurological team. Furthermore, the co-investigator plans

on using the data results within the participating facility to improve their own current stroke

program in terms of treatment options for patient’s ineligible for tPA administration. In

conclusion, the results will be shared with a local hospital in Albuquerque, New Mexico and

with the participating hospital in Kansas City, Missouri.

Practice Support for Project

There was ample support for this project at both the participating facility and the

receiving facility. The participating facility encouraged data collection and analysis of these

specific patients by obtaining a list of possible electronic medical records for personal review.

Their research team was also supportive of the project by assisting with the facilities IRB


process. A content expert from the facility have also supported the project by shared knowledge

of the facility’s data collection process. The receiving facility in New Mexico, who has benefited

from the results mostly, supported the project by assisting in discovery of limitations and

supporting the mentality of local practice change per projects results.

Benefits of Project to Practice

The evidence supporting efficiency and increased functional outcomes with

thrombectomy alone in treatment of ischemic stroke can easily be applied to practice. While

working closely with stroke patients, tPA therapy resides as a gold standard for ischemic strokes.

Currently protocols and policies ensure each ischemic stroke patient receive tPA if they meet

eligibility criterion. However, few hospitals in New Mexico are utilizing the intervention of

thrombectomy. To push hospitals and healthcare centers to include thrombectomy as a standard

of care for ischemic stroke the identification of this intervention alone must be evaluated. It

becomes the Nurse Practitioner and clinicians job to recommend thrombectomy when the patient

is ineligible for tPA administration.

All evidence supported thrombectomy practices that are often underutilized in

several healthcare areas. However, with new research supporting mechanical thrombectomy

perhaps a new unionized ‘gold standard’ will be placed in the near future. This could be a result

of advanced research on new versus old acute ischemic stroke treatment. The only future barriers

foreseen in practice change to incorporating mechanical thrombectomy, would be lacking

resources and clinicians that are trained and capable of performing thrombectomies. However,

with thrombectomy becoming more popular in large stroke centers this is a barrier that will not

hold or stop any Nurse Practitioner from ensuring that the patient receive a thrombectomy when


deemed most beneficial or essential to the patient’s needs, even if this means a transfer to a

larger stroke center.

Synthesis of the evidence

Overall, all articles supported evidence that mechanical thrombectomy is beneficial in

treating ischemic stroke in combination with tPA. There were six articles of interest included in

the literature review which became primary resource articles that were reviewed for the purpose

of answering the PICO question. There were two articles that consisted of systematic

reviews/meta-analysis; Grech et al. (2015), and Liu et al. (2016). Gautheron et al. (2018) utilized

the THRACE database to perform a randomized control study, while Muhr et al. (2017)

consisted of an exploratory cohort study. All four primary articles presented quantitative studies

that measured patient outcome after intervention with a Modified Rankin Scale. Muhr et al.

(2017) utilized both quantitative and qualitative data by including numeric number scales and

follow up questionnaires. Evidence supported by the research was strong. In every study

presented there was a statistical significance result. However, all strong evidence supported three

themes pertaining to reperfusion therapy. First, mechanical thrombectomy is effective as an

additional intervention for treatment of patients experiencing an acute ischemic stroke. Second,

thrombectomy can improve functional outcome in stroke patients when compared to standard

treatment. Lastly, there is a need to better analyze mechanical thrombectomy without the

administration of tPA in the treatment and recovery outcome of stroke patients.

Integrated Review of Literature

Efficiency of Thrombectomy

Several articles support mechanical thrombectomy in combination with tPA in treating

acute ischemic stroke. When examining mechanical thrombectomy in the reperfusion of acute


ischemic strokes research supports this method as being beneficial and effective. For example,

Liu et al. (2016) used a meta-analysis that included 16 different publications of acute ischemic

stroke patients that underwent mechanical thrombectomy. This meta-analysis supported evidence

that thrombectomy is effective in treating acute ischemic stroke. Likewise, Gautheron et al.

(2018) extracted 304 patients from the THRACE database which included patients that had

received mechanical thrombectomy after intravenous tPA versus receiving tPA alone after

stroke. This resulted in strong evidence that mechanical thrombectomy/reperfusion therapy can

benefit ischemic Middle Cerebral Artery (MCA) territory strokes. Evidence supports that

regardless of the mechanism of action, tPA or thrombectomy in combination with tPA,

reperfusion therapy remains a vital tool in the treatment of acute ischemic strokes.

Improving functional outcome. Evidence supports that patients with an acute ischemic

stroke that are treated with mechanical thrombectomy tend to have a higher functional outcome

per rehabilitation efforts as compared to standard therapy (Grech et al., 2015). Grech et al.

(2015) provided a systematic review and meta-analysis with 1288 patients to determine that

mechanical thrombectomy is highly beneficial in providing the patient with long term functional

independence. Furthermore, Muhr et al. (2017) describes reperfusion therapy as a new approach

to stroke treatment and set out to determine how reperfusion therapy effects the overall health

related quality of life (HRQoL) and activities of daily living. Although, the evidence supported

that reperfusion therapy results in mild post-stroke symptoms such as strength and long-term

functioning, these patients continue to have emotional and cognitive problems. The research

evidence supports the fact that patients that receive mechanical thrombectomy after an acute

ischemic stroke have a higher functioning outcome than those who received standard care, and

therefore it is essential that the Nurse Practitioner be aware of what specific intervention is most


beneficial in stroke treatment for patients who are experiencing an acute ischemic stroke. Finally,

as evidence of benefits to mechanical thrombectomy in treatment of ischemic stroke begin to

surface, the analysis of thrombectomy without the administration of tPA in treatment of ischemic

stroke needs to be identified to provide the best intervention possible to this population.

A need for analysis. When researching mechanical thrombectomy without tPA

administration in treatment of acute ischemic stroke, the limitation and scarceness of research

became evident. Studies supported the additional need to examine the difference between

thrombectomy outcomes as primary treatment for patient’s ineligible for tPA. For example,

several articles stated this concern as a limitation to the study. In fact, the lack of comparison

between thrombectomy treatment alone and tPA therapy has been under reported and under-

researched (Liu et al., 2016). Since tPA has a shorter time window for administration than

mechanical thrombectomy, the time constraint would need to be considered an ineligible

criterion when researching the outcomes of thrombectomy intervention alone. Likewise, co-

morbidities and prior use of anticoagulants or antiplatelet can become another criterion for

ineligibility for tPA administration and would need to be addressed to ensure the research results

are valid (Muhr et al., 2017). Finally, after review of evidence it appears many factors need to be

accounted for when analyzing stroke patient outcomes after thrombectomy. The need to provide

evidence that mechanical thrombectomy alone in intervention is beneficial in treating acute

ischemic stroke is vital to ensuring the highest functional outcome in those ineligible for tPA

administration. Factors such as co-morbidities and history of anticoagulant or antiplatelet use and

time of symptom onset prior to intervention need to be addressed to fully assess the reason for

tPA ineligibility and to identify a need for thrombectomy intervention alone in treating acute

ischemic stroke.


Literature Critique

The overall impression of the quality of the evidence is strong. The research studies

found were reliable and valid. Large sample sizes were utilized in most quantitative studies and

significant results were found in each article. The methods that were used were appropriate for

the questions being asked by using quantitative studies. The data collection process was

sufficient with minimal limitations and appropriate exclusions were applied. Generally, each

research study coincided with the others. They all produced results that were similar yet achieved

with different methods. The end results are easily applicable to practice and patient care.

Furthermore, there were only a few areas of research that could have been expanded and could

potentially be clarified in future research studies.

Strengths

The major strengths of the evidence presented was the similarity in the process of

extracting the data. Several of the studies utilized either a meta-analysis or a retrospective chart

review. They also mostly used quantitative data throughout the study. The process was consistent

in the approach of gathering data and utilizing similar population groups with cerebral large

vessel ischemic strokes. All studies also used a similar form of evaluating outcome such as the

Modified Rankin Scale post 90 days’ intervention. By having a specific pattern to discovery, all

the articles correlated and supported the main themes and results. All articles were also

significant in their findings. The data presented, such as the 90 day Modified Rankin Scale and

the benefit of thrombectomy, was of significant significance throughout all articles adding to the

strengths. Although several strengths were identified during the review of literature, there were

also many weaknesses found as well.


Weaknesses. The major weakness of the evidence presented was the fact that most

studies participants were not completely randomized. The studies, as mentioned before used

quantitative data within a meta-analysis or retrospective chart review that for the most part are

not randomized in selection. Meaning, most patients were vetting to be a part of the review. By

adding more evidence based findings of randomized, control trials and with larger sample sizes,

the identified outcomes could be considered highly valid and reliable.

Gaps. There are a few areas missing from the synthesized evidence. Most studies based

their analysis on quantitative data with one study incorporating qualitative data. To fully

understand which intervention in the treatment of acute ischemic stroke will provide the most

functional and cognitive outcomes qualitative research should be utilized as well. Also, most

patients treated were not assessed for further contributing co-morbidities such as diabetes,

hypertension and heart disease. Patients could respond to reperfusion therapies differently due to

their co-existing disorders. Furthermore, if the patient previously received tPA and received a

mechanical thrombectomy their outcome may be more positive due to the relative ease of clot

removal, therefore this should be considered when conducting further research. Lastly, some

practices may include a combination therapy of both tPA administration followed by mechanical

thrombectomy. If combination therapy is regularly practiced, it should be identified in the data

when assessing functioning outcomes after an ischemic stroke.

Limitations of existing evidence. Limitations of the studies found were co-morbidities and

prior use of anticoagulants or antiplatelet. These factors were not determined and would need to

either be included or excluded prior to intervention to ensure the research results are valid (Muhr

et al., 2017). If the aim of the overall project is to determine patient outcome in relation to

mechanical thrombectomy after an ischemic stroke then the patients’ co-morbidities and whether


they were previously taking an anticoagulant/antiplatelet or tPA needs to be assessed.

Anticoagulation is a contraindication for tPA administration but not for mechanical

thrombectomy. Likewise, if a patient has multiple co-morbidities such as hypertension, diabetes,

hyperlipidemia or heart disease they may have a different outcome with thrombectomy than

those with less disorders or diseases due to the fragility of the cerebral vessels (Bendszuz et al.,

2015). By excluding these factors from most studies and retrospective chart reviews it can be

difficult to identify which intervention is most beneficial and to which specific population.

Concepts and Definitions

While working closely with stroke patients, tPA therapy resides as a gold standard for

ischemic strokes. Currently protocols and policies ensure each ischemic stroke patient receive

tPA if in the symptom onset time window of 4.5 hours. However, few hospitals in Albuquerque,

New Mexico are utilizing the intervention of thrombectomy. To push hospitals and healthcare

centers to include thrombectomy within the gold standard for ischemic stroke care, the

identification of which intervention therapy is best suited to each individual patient’s condition,

must be evaluated. The emergency department Nurse Practitioner must evaluate tPA ineligibility

factors of each ischemic stroke patient and determine if thrombectomy is a beneficial

intervention that will provide the best functional outcome. It becomes the Nurse Practitioner and

neurologists job to recommend thrombectomy if the patient is more likely to become higher

functioning with clot retrieval or if they are outside the symptom onset time window for tPA

administration.

Theoretic Framework

Betty Neuman’s System Model Theory focuses on the holistic aspect of the patient. It

focuses on which intervention or function is best suited to stabilize and realign the patient back


to their best state of wellness. She uses the idea of primary, secondary and tertiary nursing care

and intervention. Neuman’s theory was easily applied to stroke patients and their care because

there are three aspects, such as primary, secondary and tertiary approaches when caring for these

patients. Primary would include prevention and education on stroke risk factors (Neuman &

Fawcett, 2011). Throughout the data collection process, stroke risk factors such as smoking,

hypertension, atrial fibrillation, diabetes and high cholesterol will be gathered on all cases to

determine which factor is most prevalent. Education can be provided to patients about these

identified risk factors to prevent future stroke. The secondary approach included the intervention

during a stroke, such as tPA or mechanical thrombectomy, and tertiary care falls into the

rehabilitation elements of the stroke victim. The project focused mostly on Neuman’s secondary

approach because the research question of interventional thrombectomy being a beneficial

treatment to ischemic stroke patients. Furthermore, the research also encompasses the third

approach by identifying if the patients had an improved outcome after thrombectomy. Since an

improved outcome was found with thrombectomy, then the patient will be better capable of

participating in rehabilitation due to less stroke residual symptoms. Her theory also focused on

taking the best approach possible to get the patient back to full wellness which is very relevant to

the concept of whether thrombectomy is a suitable intervention for ischemic stroke patients

(Neuman & Fawcett, 2011).

Project design and methodology

The project consisted of a retrospective chart review of ischemic stroke patients

conducted within a large, 629-bed, Comprehensive Stroke Center in Kansas City, Missouri. The

chosen facility performs both thrombectomy procedures and tPA administration for eligible

ischemic stroke patients. The sample included at least 100 cases treated at the facility within the


last three years (2015-2018). The sample population included both female and male candidates

over the age of 18. Race was not considered for inclusion or exclusion criteria for the project, but

gathered as demographic data as a significant indicator of stroke risk. Inclusion criteria included

patients that arrived within the symptom time frame to undergo thrombectomy who were

ineligible for tPA administration. The patients presented with ischemic stroke symptoms and had

a positive CT head angiogram/perfusion for a large vessel occlusion stroke. Pre-existing

anticoagulation therapy or antiplatelet therapy was not either inclusive or exclusive to this

project. Exclusive criteria included the use of tPA administration prior to a thrombectomy

procedure. The facility’s stroke coordinator assisted in retrieving charts for review.

By following the inclusion and exclusion criteria, a retrospective approach to reviewing

applicable patient cases was completed. Once the charts were reviewed a measurement of patient

improvement post thrombectomy was located by examining the patient’s pre-intervention NIHSS

(National Institutes of Health Stroke Scale) score as compared to their discharge NIHSS score.

This scale is included in the facility’s stroke protocol as a mandatory, standard measurement.

There was no subjectivity and was universal in any setting such as the Emergency Department

and Intensive Care Unit. Due to minimal risk of the research and the non-effect on the patient’s

rights and welfare, consent did not need to be obtained from the chosen chart reviews. However,

the facility did require additional IRB approval and mandatory requirements such as evidence of

CITI training prior to project initiation.

Analysis

The test chosen for this project’s data analysis was a paired t-test. A paired t-test is often

used when there is a need to compare two groups (Shier, 2004). For example, the need to

compare one set of values or population group to another set of values or population group. This


type of statistical test is commonly seen in before and after studies to determine if a significant

change or when improvement has occurred (Shier, 2004). The data collected was quantitative

and the mean was found on both pre-and-post intervention NIHSS prior to analysis with a paired

t-test. The NIHSS change scores were calculated by subtracting the pre-thrombectomy score

from the post-thrombectomy score (post-intervention minus pre-intervention). A Paired-samples

t-test was conducted on the mean change NIHSS scores. The significance level was set at

alpha=0.05.

The rationale behind using a paired t-test was due to the need to compare pre- and –post

NIHSS to determine patient outcome. Overall, the mean of both the pre-and-post thrombectomy

NIHSS needed to be analyzed with a paired t-test to determine if the patient deteriorated or if

they improved due to mechanical thrombectomy alone in the treatment of ischemic stroke. By

comparing these means in a paired t-test a result that analyzes before and after results could be

made. Overall, this was the correct analysis to perform on this scholarly project to determine true

patient outcome.

Resources

Overall, the resources needed included leadership from the stroke coordinator to assist in

determining and identifying charts for review. Also, since the measurement of outcome was

based on a clinical NIHSS, all nursing faculty had to be compliant with the hospitals protocol on

completing a baseline NIHSS and a discharge NIHSS. The use of the emergency department for

evaluation of these stroke candidates, as well as the Neuro-Interventional radiologist needed to

be included for consistency throughout the project. The use of the CT machine was vital when

attempting to diagnose the patient with a large vessel acute ischemic stroke. Lastly, since this

project was completed as a retrospective approach the cost was completely insignificant.


Budget and timeline

As stated before, this project carried no known cost, funding or grants. Once the approval

of the IRB, the plan included extracting eligible charts for review. This process was free of

charge per the facility’s stroke coordinators efforts. Furthermore, the data analysis was also free

of charge per assistance from Maryville University’s statistician, stroke coordinator and main

researcher. Although the cost of thrombectomy or CT imagining could have been considered,

since these measures have already been completed and paid for they were not considered within

this specific project. Likewise, the cost of nurse work production could also be connected,

however, again the production hours had already been accounted for. The timeline of this project

seemed to stay on tract. The IRB approval, both within the University and facility’s preference

was achieved by January 2019. Data collection began immediately and was completed

throughout the following 8 weeks. Data analysis took place during the following 3 weeks after

data collection. A final report was completed and finalized by May 2019.

Protection of Human Subjects

When data was collected for this project the main concern was conducting a breach of

confidentiality. Since, the participants did not need to be consented the use of their private

information was shared mostly without their knowledge. To protect the human rights of each

individual participant a request to remove identifying information, such as names or initials,

from the patient’s chart was included. Any further identifying information such as age and

gender was carefully used within the final phases as to not expose any of the participants. A key

linked to the data collection spreadsheet was the only file with identifying information. This key

was locked within a password protected computer within the facility. The key was then


destroyed per facility after analysis had been completed. All measures were taken to protect and

respect the terms of HIPPA for the patients included within the study.

Findings

One hundred cases were obtained through a randomized retrospective chart review

between the years of 2015-2018. Of the cases fifty-eight males and forty-two females were

identified, with a mean age of seventy-three. Eighty-two present were Caucasian, fourteen

percent black with a remaining small one percent each of Vietnamese, Hawaiian and American

Indian. Also, a small one percent of the population was unknown of race due to lack of

documentation. Inclusion criteria included the presentation of an acute ischemic stroke who

received mechanical thrombectomy and who were ineligible for tPA administration. Exclusion

criteria included the administration of tPA. Stroke risk factors were also gathered from the

sample size. It was found that seventy-two percent of the 100 cases did not have diabetes, while

twenty-five percent was positive for diabetes, three percent unknown. Forty-three percent

presented with high cholesterol, fifty three percent without and four percent unknown. The risk

factor of current tobacco use (smoking) was found in thirty-one percent of the cases, however

twenty percent were found to be former smokers. Thirty-two percent of the cases did not smoke,

while an under documented seventeen percent was unknown. Of all the risk factors hypertension

was found to be the most predominant with a total of seventy-eight percent of the cases with high

blood pressure. Only eighteen percent of the cases were without hypertension and four percent

left unknown. Atrial fibrillation was seen in thirty-five percent, leaving sixty-one percent absent

of atrial fibrillation and a remaining four percent unknown.

All together the reason for tPA inedibility was mainly due to the patient

presenting outside of the ‘symptom onset time-window’ to receive tPA. A robust seventy percent


of the cases did not receive tPA based upon their time of symptom onset. Nineteen percent were

without tPA because of a history of anticoagulant use. Five percent had recently had a surgery of

some sort and four percent had a history of recent stroke prior to the current episode. A small

percentage of one percent each was left without tPA due to active bleeding and uncontrolled

hypertension. National Health Institutes Stroke Scale (NIHSS) was used in comparison of pre-

and-post thrombectomy outcome. Therefore, the data collection of pre-thrombectomy NIHSS

and post-thrombectomy NIHSS were utilized in the analysis to identify patient outcome. A

paired samples t-test was completed with a mean pre-thrombectomy NIHSS score of eighteen

and a mean post-thrombectomy score of nine. The paired t-test was utilized by subtraction of

post minus pre, with a p=0.05. Overall t=- 9.89, giving a decrease of nine on the post-

thrombectomy NIHSS.

Interpretation of Findings

According to Polit and Beck (2017) the researcher must ask specific questions when

interpreting quantitative data and results. Therefore, the first question is if all the important data

is discussed. All data including, age, gender, risk factors (diabetes, hypertension, atrial

fibrillation, smoking, high cholesterol) and reason for tPA ineligibility were discussed. Age is

presented as a mean (73) while the other criteria is presented in percentages. There were 58

males and 42 females collected at random. The population consisted of Caucasian (82%), black

(14%) and only a small make up of Vietnamese, Hawaiian and American Indian (1% each).

Twenty-five percent of the cases had diabetes while only forty-three percent had high

cholesterol. Hypertension was found in seventy-eight percent of the cases and thirty-five percent

presented with atrial fibrillation. There was a split between the population who smoked. Thirty-

one percent were current smokers, twenty percent were former smokers and thirty-two percent


never smoked. Overall the most common reason for tPA ineligibility was found to be time of

symptom onset outside of the tPA administration window (70%).

A paired t-test was conducted on the pre-and-post thrombectomy NIHSS scores

and is discussed in terms of a p-value of 0.05. Limitations of the study included a sample size of

100 cases only and a population predominant in the Caucasian race. There were no known

threats or biases in the study. The data was collected at random through personal chart review.

The evidence that is in support of the interpretation of thrombectomy improving patient outcome

was that the paired t-test resulted in a t=-9 when post NIHSS was subtracted from pre NIHSS.

Meaning that patients NIHSS scores improved by around 9 points after receiving thrombectomy.

This evidence was very persuasive in demonstrating a positive correlation with the treatment.

There was no supplementary analysis undertaken when conducting the paired t-test. This is

because there was no need for extra analysis. A paired t-test clearly demonstrates a difference

between means, especially in pre-and-post scores, which is exactly what this study entailed.

There were no convincing alternatives to the findings. Although risk factors were collected for

review they did not seem to imply a difference in the statistical analysis of the study.

Furthermore, age and gender did not play a role in the findings due to both male and

female, as well as age range, both responded to thrombectomy similarly. The results seem

precise due to the randomization of the data collected and the three-year period in which the

cases occurred. The magnitude of the effects was immense due to the overwhelming positive

correlation between thrombectomy and patient outcome. As far as generalizability, the research

was conducted in one facility and it is unknown if the same results would be found in another

facility. The only variable that would change is the physician performing the thrombectomy. Due

to differences in technique and practice the results may be slightly different with other physicians


in another facility. However, the practice of thrombectomy can benefit other populations and be

used for other conditions, such as an acute myocardial infarction in the heart disease population.

Discussion

The overall results of the research concluded that in a sample of 100 cases who received

mechanical thrombectomy alone in the treatment of an ischemic stroke, those patients

experienced a decrease in their NIHSS scale by nine points, implying an improved patient

outcome. The risk factors gathered throughout the study implied hypertension is often found in

the presence of an acute ischemic stroke. Another large correlation found within the stroke risk

factors was smoking, due to the large sample size that were currently or had been a former

tobacco smoker. The cause for ineligibility of tPA administration was largely related to the

patient’s time of symptom onset. With the results found in this quantitative randomized

retrospective chart review with analysis of a paired t-test, promotion for the practice of

mechanical thrombectomy should be supported. In areas that are without mechanical

thrombectomy, it would be beneficial to transfer the patient to a facility capable of the procedure.

Currently, emergency departments in the local area rely of nurse practitioners to provide care

that will provide the patient with the best possible outcome. Therefore, the knowledge of

beneficial outcomes with the treatment of mechanical thrombectomy alone in the acute stroke

population is vital.

Previous research trials have found a correlation between positive patient outcome with

dual therapy (tPA plus thrombectomy) as well as tPA administration alone. In the future, it

would be beneficial if a similar research study could be conducted on mechanical thrombectomy

alone with a larger sample size and throughout several different facilities combined. Practice

recommendations include supporting the use of mechanical thrombectomy in patients’ ineligible


for tPA administration as well as advocating for patient transfer to thrombectomy capable

facilities. Finally, with the clear presentation of hypertension and smoking in the majority of the

cases, smoking cessation and management of hypertension should be discussed and encouraged

with all patients. This education can be provided in any healthcare setting by advanced practice

providers and could even begin at a local community level.

Limitations

The study included a retrospective chart review by utilizing electronic medical records.

The data was quantitative in that scores of a standardized scale were collected as well as

documented stroke risk factors. The limitations found within this study were mostly found within

the data collection process. Some data pertaining to discharge NIHSS were missing in some

cases. The reason behind the absence of documentation was unknown. However, since this data

was ultimately missing in some electronic medical records, these cases could not be included

within the study. Furthermore, the data was collected by one researcher through personal chart

review, therefore there is a possibility of data entry error. Data entry error was attempted to be

minimized by ensuring that the data collected was transcribed in multiple formats for extensive

review of conflicting values after the collection process and before analysis.

Implications of Findings and Recommendations

The implications of the findings would recommend that thrombectomy be used as

treatment for patients experiencing an ischemic stroke and who are ineligible for tPA

administration. Clinical practice should incorporate the practice of thrombectomy within their

facilities. Likewise, nurse practitioners should carefully assess acute strokes for ineligible tPA

criteria and support the treatment of thrombectomy in this specific population. Studies have

suggested tPA as the gold standard of treatment and have shown benefits of dual treatment (tPA


plus thrombectomy) (Gautheron, et al., 2018). However, a large population of patients present

with ineligible tPA criteria, such as time of symptom onset, prior stroke or surgery or are

currently on anticoagulants. Thus, the need for quick effective intervention to treat ischemic

stroke is vital and with proper analysis it appears thrombectomy is highly beneficial to the

patient’s outcome, regardless of age, gender and stroke risk factors. The statistical and clinical

significance parallel each other because the result which proved to be significantly significant

also plays a large role in patient outcome, implying that the patient has a significant (positive)

outcome as well.

Conclusion

In conclusion, after analysis of a paired t-test calculating the difference between means

(post NIHSS minus pre NIHSS) the results demonstrated a significant difference between

outcomes. With a p-value of 0.05 and an overall t= -9, the loss of NIHSS points after

thrombectomy dropped by 9, indicating patient improvement. Demographic data and stroke risk

factors were gathered as additional data for review and arranged as means and percentages. The

overall practice recommendation would be to assess for thrombectomy indication and support the

use of thrombectomy in the ischemic stroke population that is ineligible for tPA administration.


References

Casey, G., (2018). Understanding stroke. Kai Tiaki Nursing New Zealand, 24 (2).

Fischer, U., Kaesmacher, J., Molina, C., Selim, M., Alexandrov, A., & Tsivgoulis, G., (2018).

Primary thrombectomy in tPA (tissue-type plasminogen activator) eligible stroke patients

with proximal intracranial occlusions. Stroke, 49, pg. 265-269.

Gautheron, V., Xie, Y., Tisserand, M., Raoult, H., Soize, S., Naggara, O., Bourcier, R., Richard,

S., Guillemin, F., Bracard, S., & Oppenheim, C., (2018). Outcome after reperfusion

therapies in patients with large baseline diffusion-weighted imaging stroke lesions a

THRACE trail (mechanical thrombectomy after intravenous alteplase versus alteplase

alone after stroke) subgroup analysis. Stroke, 49, pg. 750-753.

Grech, R., Schembri, M., & Thornton, J., (2015). Stent-based thrombectomy versus intravenous

tissue plasminogen activator in acute ischemic stroke: a systematic review and meta-

analysis. Interventional Neuroradiology, 21 (6).

Liu, Y., Zhang, L., & Hong, P., (2016). Efficacy and safety of mechanical thrombectomy in

treating acute ischemic stroke: a meta-analysis. Journal of Investigative Surgery, 29.

Melnyk, B. & Fineout-Overholt, E. (2015). Evidence-based practice in nursing and healthcare:

A guide to best practice. China: Wolters Kluwer.

Muhr, O., Persson, H., & Sunnerhagen, K., (2017). Long-term outcome after reperfusion-

treatment stroke. Rehabilitation Medicine, 49.

Neuman, B., & Fawcett, J., (2011). The neuman systems model. New York, NY: Pearson.

Polit, D., & Beck, C. (2017). Nursing research: Generating and assessing evidence for nursing

practice (10th ed.). Philadelphia, PA: Lippincott, Williams, & Wilkins. ISBN 978-1-4963-0023-2


Shier, R. (2004). Statistics: 1.1 paired t-tests. Mathematics Learning Support Centre. Retrieved

from http://www.statstutor.ac.uk/resources/uploaded/paired-t-test.pdf


Appendix A

Tables Table 1 Paired t-test Post/pre thrombectomy means

Post Thrombectomy Pre Thrombectomy Mean 9.24 18.2 Variance 80.56808081 63.15151515 Observations 100 100 Pearson Correlation 0.432785977 Hypothesized Mean Difference 0 df 99 t Stat -9.895981362 P(T<=t) one-tail 9.22366E-17 t Critical one-tail 1.660391156 P(T<=t) two-tail 1.84473E-16 t Critical two-tail 1.984216952

Figure 1.8- Paired t-test demonstrating post thrombectomy NIHSS means minus pre

thrombectomy means. P-value 0.05, t= -9.


Appendix B

Figure 1.7- tPA ineligible criteria demonstrated in percentage in 100 thrombectomy cases for the

treatment of ischemic stroke.

70%

5% 4%

19%

1% 1%

tPA ineligibility

Outside time-window

Prior surgery

Prior stroke

Anticoagulants

Active bleeding

Uncontrolled Hypertension

mechanical thrombectomy in improving stroke...

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