Cost-effectiveness of Access to Critical Cerebral Emergency Support Services (ACCESS): a neuro-emergent telemedicine consultation program

Abstract

Aims: Access to Critical Cerebral Emergency Support Services (ACCESS) was developed as a low-cost solution to providing neuro-emergent consultations to rural hospitals in New Mexico that do not offer comprehensive stroke care. ACCESS is a two-way audio-visual program linking remote emergency department physicians and their patients to stroke specialists. ACCESS also has an education component in which hospitals receive training from stroke specialists on the triage and treatment of patients. This study assessed the clinical and economic outcomes of the ACCESS program in providing services to rural New Mexico from a healthcare payer perspective.

Methods: A decision tree model was constructed using findings from the ACCESS program and existing literature, the likelihood that a patient will receive a tissue plasminogen activator (tPA), cost of care, and resulting quality adjusted life years (QALYs). Data from the ACCESS program includes emergency room patients in rural New Mexico from May 2015 to August 2016. Outcomes and costs have been estimated for patients who were taken to a hospital providing neurological telecare and patients who were not.

Results: The use of ACCESS decreased neuro-emergent stroke patient transfers from rural hospitals to urban settings from 85% to 5% (no tPA) and 90% to 23% (tPA), while stroke specialist reading of patient CT/MRI imaging within 3 h of onset of stroke symptoms increased from 2% to 22%. Results indicate that use of ACCESS has the potential to save $4,241 ($3,952–$4,438) per patient and increase QALYs by 0.20 (0.14–0.22). This increase in QALYs equates to ∼73 more days of life at full health. The cost savings and QALYs are expected to increase when moving from a 90-day model to a lifetime model.

Conclusion: The analysis demonstrates potential savings and improved quality-of-life associated with the use of ACCESS for patients presenting to rural hospitals with acute ischemic stroke (AIS).

Keywords:

• Cost effectiveness
• stroke
• stroke care
• telemedicine
• patient transport
• tPA
• rural healthcare

Introduction

Stroke is the leading cause of serious long-term disability and the fifth leading cause of death in the US¹. It is 1.45-times more prevalent in rural areas than in urban settings (15.1 per 1,000 individuals and 10.4 per 1,000 individuals, respectively)². Stroke mortality is also higher in rural states like New Mexico, because much of the population lives far from a neurological treatment center. When a neuro-emergent condition presents at a rural emergency department, the patient is frequently transferred, often by air ambulance, to a hospital with a stroke specialist or stroke unit. In the majority of these cases, neurologists at the receiving hospital determined that the patient could have been properly treated at the rural facility.

About 2.1 million New Mexicans, 33% of them in rural areas, depend on the University of New Mexico Hospital (UNMH) for critical neuro-emergent services. Out of 33 counties, 31 are medically under-served areas, resulting in patients being transported long distances to UNMH to receive neuro-emergent care services.

Through Access to Critical Cerebral Emergency Support Services (ACCESS), UNMH and its partners leveraged community-based coalitions to reduce the cost of neuro-emergent services and improve outcomes for patients with neuro-emergent disorders such as complicated mild traumatic brain injury (mTBI) and stroke. ACCESS built and expanded existing partnerships in a comprehensive neurology and neuro-emergent telehealth network to provide critical state-of-the-art telehealth services to all NM providers and their patients. The program partnered with 12 regional hospitals to provide optimum triage and care for these patients. These 12 hospitals also provided 6 months of patient data prior to their first consultation with ACCESS, to get base line trends. Optimum triage and care was provided by radiographic enhanced neuro-emergent consultations. From May 2015 to August 2016, ACCESS provided a total of 777 consultations (Figure 1).

Figure 1. ACCESS program—cumulative consults by month to August 2016.

ACCESS focused on improving the health of geographically, clinically, and socioeconomically diverse populations by providing comprehensive care that extended beyond the clinical service delivery setting. ACCESS integrated an educational component via traveling educators and a telehealth educational program. Through the education component, hospitals get training from a stroke specialist to help them better utilize ACCESS and become more comfortable with keeping patients.

With ACCESS, the participating ERs have a telehealth platform that includes rapid radiograph image transfer and two-way audiovisual capacity, as well as report generating capacity. This enables consulting neurosurgeons and neurointensive care specialists to review imaging and talk with/examine the patient and generate a report. This platform is used at the bedside to examine and assess patients, increases the confidence and decision-making capacity of local and tertiary care physicians, and increases family members’ confidence that decisions for their loved ones were optimal.

Net Medical Express Solutions (NMXS) has developed this telehealth technology to facilitate comprehensive consultation services to hospitals at no upfront cost to the hospitals. Instead, the hospitals will pay a per consultation fee to a specialist for assessment and plan-of-care decision-making. The innovation in the ACCESS payment model is that, after funding ends, hospitals will reimburse the neuro-emergent disorder consultation fee on a per encounter basis. In the current program for rural stroke care, 12 hospitals pay ∼$600 per consult with a UNMH neurologist; $275 goes to NMXS to cover overhead, maintenance, support, and profit; the other $325 reimburses the neurologist’s time, assessment, and program staffing costs.

ACCESS enables healthcare professionals (HCPs) to treat most patients with neurological, and non-operative neurosurgical disorders locally when indicated, instead of transporting them to UNMH. Audiovisual capabilities allow neurologists and neurosurgeons at UNMH to review radiographic images and consult with referring HCPs and their patients virtually to deliver enhanced treatment advice. HCPs can also generate a written report within minutes. Patients who necessitated tertiary-level intervention were stabilized and optimized for transport to UNMH. Patients who did not require tertiary-level emergent care were triaged to rural hospitals and referred to appropriate clinics for follow-up care.

ACCESS is managed by the UNM Department of Neurosurgery and the UNM Center for Telehealth. UNM and NMXS partnered to provide the telehealth and teleradiology infrastructure and equipment. NMXS is responsible for installing hardware and software components and helping to train the IT telehealth workforce. The UNM Center for Health Care Informatics collects quality metrics, health measures, cost-effectiveness data, and workforce-related metrics.

Telehealth-enhanced neurosurgical consultation is routinely used in Europe. For example, Fabbri et al.³ showed that observation in a neurosurgical unit or in a peripheral hospital after telehealth-enhanced neurosurgical phone consultation is safe and does not result in worse outcomes. In one of our studies by Moya et al.⁴, we showed that telehealth-enhanced consultations in New Mexico resulted in care management recommendations or avoided transports in 50% of cases. We saw similar results with our teleradiology program at the Gallup Indian Med. Ctr., where 45% of transfers could be avoided^5,6. Implementing this telehealth system in New Mexico will improve efficiency by achieving wider access to effective neuro-emergent care, reducing healthcare costs through appropriate resource management, and improving quality of care at the referral center due to timely expert consultation.

Acute ischemic stroke (AIS) represents 80% of all strokes, and the administration of tPA within a 3-h window of onset can significantly reduce disability and improve stroke outcomes^7,8. In order to be a candidate for tPA therapy, patients need to seek emergency medical treatment and undergo appropriate imaging studies with interpretation by a radiologist or a stroke-trained neurologist within 3 h of stroke onset. Patients were characterized as having an ischemic stroke if they had a sudden loss of blood circulation to an area of the brain, resulting in a corresponding loss of neurologic function. If this was caused by thrombotic or embolic occlusion of a cerebral artery, then it was defined an acute ischemic stroke. Delays in arrival to rural emergency rooms, a lack of expedited emergency department stroke care assessment protocols, and the absence of expert stroke-trained physicians in rural hospitals result in fewer than 3% of eligible patients receiving tPA⁹. From our data we find that rural New Mexico tPA utilization is ∼0.88%. Transfer of these patients to urban hospitals leads to a further delay in diagnosis and lost opportunity to treat with tPA within the 3-h window. These unnecessary transfers lead to increased patient morbidity; increased cost of care; and significant inconvenience to families, who often must travel for hours to be with their loved one. The ACCESS program makes it possible for remote, real-time consultation with expert neurologists, providing a more timely diagnosis and expedited treatment.

While ACCESS can improve clinical outcomes, cost is also an important factor in a hospital’s decision to adopt the ACCESS program. In the US, there are currently no established charge codes for neuro-emergent consultations. This means that hospitals need to be willing to use and reimburse telemedicine consultations for neuro-emergent care in order for the program to be sustainable. Other US teleneurology programs charge maintenance fees or annual subscription fees^10,11. The ACCESS program charges hospitals only on a per consultation basis. This minimizes the cost of care to rural hospitals that have a relatively rare, but time dependent, need for neuro-emergent decision-making.

The purpose of this study was to assess the clinical and economic outcomes of a state-wide ACCESS program in New Mexico. Although other published studies have examined the problem theoretically and offered information on how to establish a program, the improved health outcomes for the other programs come at a large cost, between $50,000 and $100,000 per QALY^9–14. ACCESS is the first to our knowledge to show a cost saving in the 90-day assessment, while still improving patient health outcomes. This study assesses the impact of ACCESS on early patient care decisions for the administration of tPA and of treating patients in rural hospitals rather than transferring them to tertiary care facilities.

Methods

Data from the ACCESS program includes emergency room patients in rural New Mexico from May 2015 to August 2016. From this data, we are able to see the change in patient transfer rates and tissue plasminogen activator (tPA) utilization. We then used a model to examine the effect of ACCESS on 90-day health outcomes and potential cost savings where our data is limited. Cost of care and resulting quality adjusted life years (QALYs) were taken from existing literature. Outcomes and costs have been estimated for patients who were taken to a hospital providing neurological telecare and patients who were not. A protocol describing the study was submitted to the Human Research Review Committee Institutional Review Board and it was deemed exempt from review (15-012).

Model overview

A decision tree model was developed to estimate the costs and effectiveness with and without the ACCESS program. The tree provides a mathematical framework for modeling decision-making in situations where outcomes are partly random and partly under the control of a decision maker. The model compares patients that received care in the ACCESS program (ACCESS) vs a non-program setting (Non-ACCESS).

The decision and treatment process shown in Figure 2 was taken from previous models^15–17 and current standards of practice, and has been modified to fit the current ACCESS program. The decision node in the model identifies whether the hospital has ACCESS or does not have ACCESS.

Figure 2. Stroke decision tree model.

The first chance node (Figure 2) separates patients who receive either a computed tomography (CT) scan or magnetic resonance imaging (MRI) read by a stroke specialist in less than or equal to 3 h from symptom onset from those who do not. If imaging read by a stroke specialist supports the diagnosis of ischemic stroke and the symptom onset occurred in less than or equal to 3 h, the patient was a candidate to receive tPA. Only AIS patients that received scans within that 3-h window and did not have an advanced infarction received tPA. The second chance node categorizes patients that are candidates for tPA into those who received tPA and those who do not. The third chance node identifies whether the patient was admitted to the original facility or transferred to another facility. The originating hospital had to have the necessary resources to care for any patient that was not transferred. The final chance node for each branch is the resulting health state.¹ We used the seven health states defined by the modified Rankin scale (Table 1) to determine health outcomes^18–20.

Table 1. Modified Rankin scale.

mRS score	Description
0	No symptoms
1	No significant disability
2	Slight disability
3	Moderate disability
4	Moderately severe disability
5	Severe disability
6	Dead

Transition probabilities

The transition probabilities (Table 2) of receiving a scan within the 3-h window, being transferred to another hospital, and receiving tPA come directly from the findings of the ACCESS program.

Table 2. Stroke transitions.

Stroke transitions	Teleneurology (range)	Non-teleneurology (range)
Scan <3 h	0.22 (0.16–0.27)	0.02 (0.01–0.03)
Scan >3 h	0.78 (0.60–0.98)	0.98 (0.91–0.99)
Transfer/tPA	0.23 (0.17–0.29)	0.90 (0.80–0.99)
No transfer/tPA	0.77 (0.59–0.97)	0.10 (0.08–0.13)
Transfer/no tPA	0.05 (0.04–0.06)	0.85 (0.76–0.91)
No transfer/no tPA	0.95 (0.88–0.99)	0.15 (0.12–0.19)
Scan <3 h/tPA	0.84 (0.78–0.92)	0.44 (0.37–0.51)
Scan <3 h/no tPA	0.16 (0.13–0.20)	0.66 (0.54–0.78)
Scan >3 h/tPA	0.00 (0.00–0.00)	0.00 (0.00–0.00)
Scan >3 h/no tPA	1.00 (1.00–1.00)	1.00 (1.00–1.00)

Cost inputs

The expenses incurred were based on the probabilities in the decision tree. The potential cost of care includes ACCESS consultation fee, transfer costs, cost of tPA administration, and final diagnosis costs. Final diagnosis costs were taken from inpatient costs, length of average stay, and other medical costs associated with 90-day stroke outcomes^21–24. The higher the mRS, the more costly the care, as these patients generally require more and higher level interventions²⁵. All cost inputs found in Table 3 were set to 2015 US dollars using the medical care services component of the Consumer Price Index²⁶.

Table 3. Costs.

	Costs (range)
Cost of scan	$1,180 ($885–$1,475)^21^a
Cost of transfer	$5,125 ($3,843–$6,406)^30^b
Average 90-day patient costs with mRS 0–3	$15,400 ($11,550–$19,250)^21^c
Average 90-day patient costs with mRS 4–5	$30,327 ($22,520–$37,533)^21^c
Average 90-day patient costs with mRS 6	$32,347 ($24,260–$40,433)^21^c
Cost of consultation	$600 ($450–$750)

^a computed tomography or CT, or magnetic resonance imaging or MRI.

^b Based on weighted average of air and ground transportation costs.

^c Based on MS-DRG.

Table 4. QALYs.

	QALY^21	Range^21	Years of remaining life^30	Range^30	If tPA^30	If no tPA^30
mR0	0.85	0.80–1.00	15	13–17	0.18 (0.13–0.23)	0.11 (0.06–0.16)
mR1	0.80	0.75–0.95	11.7	8.4–14.9	0.24 (0.19–0.29)	0.16 (0.11–0.21)
mR2	0.65	0.68–0.90	8.4	7.6–9.3	0.07 (0.02–0.12)	0.12 (0.07–0.17)
mR3	0.50	0.45–0.65	6	5.2–6.8	0.13 (0.08–0.18)	0.14 (0.09–0.19)
mR4	0.35	0.10–0.40	3.7	2.9–4.6	0.13 (0.08–0.18)	0.20 (0.15–0.25)
mR5	0.20	0.00–0.32	2.5	1.4–3.5	0.06 (0.01–0.11)	0.07 (0.02–0.12)
mR6	0	0.00–0.00	0	0–0	0.18 (0.13–0.23)	0.21 (0.16–0.26)

QALYs

We use QALYs as the outcome for effectiveness in this article. QALYs are constructed by multiplying the years of remaining life with the utility weight associated with the health outcome. Utility weights are measured on a scale, where 1.0 represents a state of perfect health and 0.0 represents death. The health outcome utility weight used here were found using the CEA registry and their resulting sources^27–29. All QALY inputs used are found in Table 4.

Model outputs

Model outputs included total costs, potential effectiveness outcomes, and incremental cost-effectiveness ratios (ICERs) comparing a patient treated for an acute/emergent condition within the ACCESS program with a patient treated outside the program. Total costs included all components described above and were summed across all model outcomes for in program and out of program patients. Effectiveness was measured as mean quality adjusted life years (QALYs) across all outcomes for both in and out of program. The analysis of the model was conducted using the TreeAge Pro 2013 (TreeAge Software, Williamstown, MA).

Sensitivity analysis

Our inputs described above are point estimates taken from the very specific patient populations of New Mexico. A one-way sensitivity analysis and Monte Carlo simulation (MCS) were performed to determine whether varying the magnitudes of these inputs affected our results. We used the results of the one-way sensitivity analysis to create a tornado diagram showing inputs impacts on the ICER. A probabilistic sensitivity analysis was also performed using a second-order MCS with 10,000 iterations. In the MCS all inputs varied at once rather than one at a time. Each inputs variation was based on random draws from a distribution. Distribution assumptions and ranges for each parameter are shown in their respective tables.

Results

The results show that the ACCESS program is a dominant strategy compared to no program, as it is both cost saving and more effective (Table 5). The results provide evidence that ACCESS provides cost savings of $4,241 per patient, with the greatest cost savings attributable to the decrease in unneeded patient transport. The cost savings portion from transportation was $3,729, while the cost savings portion from improved health outcome from tPA utilization was $512. There was an increase in effectiveness of 0.20 per patient.

Table 5. Cost-effectiveness results.

	ACCESS	Non-ACCESS	Difference	ICER
Total costs	$25,557^a	$29,798^a	–$4,241^b	–$21,205
QALYs	4.43^c	4.23^c	0.2020^d	Dominant^e

Abbreviations. ICER, incremental cost-effectiveness ratio; QALY, quality-adjusted life-year.

^a Average cost per patient.

^b Average cost savings per patient.

^c Average QALY per patient.

^d Average QALY gained per patient.

^e ACCESS is cost savings with higher QALY, meaning it is the dominant option.

Sensitivity analysis

A tornado sensitivity analysis (Figure 3) was performed to determine whether the results were sensitive to certain parameters in the model by varying inputs within their ranges while holding other inputs constant. The horizontal bars in Figure 3 represent the ICER range associated with the high and low values for that particular input parameter. The inputs that changed the ICER dramatically for this model were the cost of transfer, the probability of having the scan read in less than 3 h, and the probability of receiving tPA if a candidate. However, even with large swings in these parameters, the model provides evidence that ACCESS is still potentially cost saving. A Monte Carlo analysis was also performed for robustness. The results of the Monte Carlo simulations show potential mean cost savings per patient of $4,197 ($3,952–$4,438). The mean QALYs per patient was 0.18 (0.14–0.22).

Figure 3. Tornado analysis.

Discussion

The high cost and low quality-of-life outcomes from stroke affect patients, their families, and the healthcare system as a whole. The analysis provides insight into costs and effects of stroke while allowing exploration into topics requiring further study. The analysis examined the costs, benefits, and healthcare payer impact of the ACCESS program compared with no program.

The analysis showed that the ACCESS program was potentially cost saving. While the high savings came primarily from avoiding the high cost of transport, there was still a net saving when the cost of transportation dropped to zero. This saving stemmed from overall better patient outcomes. The increased usage in tPA leads to better stroke outcomes^2,10,12. Better stroke outcomes mean less disability and avoided healthcare costs. AIS patients showed this sharp increase in QALYs due to the fact that treatment for ischemic stroke is time sensitive and can be directly improved by the early administration of tPA^{16,17,21,25,27–30}. The sensitivity analysis determined that the model was robust when inputs varied up to 25%.² In all these scenarios, the program was shown to be cost saving and increased QALYs for patients. While hemorrhagic strokes and stroke mimics are also time sensitive, there is nothing in the literature to show a direct benefit from early diagnosis. Hemorrhagic strokes are also not as common as AIS, so adequate data has not yet been obtained for analysis.

Rural hospitals should only transfer a patient who requires a higher level of care³⁰. While the avoidance of unnecessary transfer of patients leads to lower cost, keeping patients in originating hospitals has much broader effects. Transporting patients out of their communities and away from support systems creates personal and financial inconvenience for patients and their families, while also resulting in lost revenue to the transferring hospital. These findings are consistent with other studies done on teleneurology programs, showing potential cost savings from the program perspective, and lower transfer rates that are associated with increased cost-effectiveness^{9–12,30–33}. The full effect of a decrease in unneeded transports is outside the scope of this paper.

The ACCESS program is uniquely suited for rural hospitals treating a relatively small number of stroke patients. Without the ACCESS program, a rural hospital would need to have a stroke-trained physician on call at all times. This is not only cost prohibitive, but unreasonable from a resource perspective, as there are currently not enough appropriately trained neurologists practicing in the US to fill this need. A hospital with the ACCESS program pays only $600 per consultation. In addition, the ACCESS program means quicker access to a neurologist, earlier diagnosis, and, for AIS patients, a greater likelihood of receiving tPA; this improves patient outcomes and leads to lower long-term costs, including decreased hospital inpatient days, decreased rehabilitation costs, decreased inpatient nursing home placement, and less caregiver burden.

Technology can remotely connect patients to expert clinicians, minimizing negative impacts on geographically disparate patient populations; however, new technologies and programs must be evaluated in order to understand their costs and outcomes. This study demonstrates that a patient seen as part of the ACCESS program has a potential cost savings of $4,241, and gains 0.20 QALYs after the initial care, compared to a routine non-program patient. The cost savings stemmed from a reduction in unneeded transportation and better health outcomes that required less hospital intervention. The ACCESS program was economically dominant over current routine care. For every 1,000 patients treated in this program, there is an average cost saving of $4,241,000, making it easily justifiable in today’s healthcare system. Insurance plans, both government and non-government, should seek out teleneurology programs for their clients, and should reimburse at a rate that includes the cost of having specialty physician coverage, as well as the cost of telecommunication, and stroke specialist training. These costs are more than that of a scheduled office visit. The healthcare system has reached a new stage where stroke patients can have access to a neurologist without having to live in a large city.

Similar teleneurology studies revealed similar results. A Cost Effectiveness Analyst (CEA) of a similar program in Arizona showed a teleneurology network could lead to a short-term cost increase, but long-term gains from the improvement in health outcomes and the decreased need for follow-up care³⁰. A comparable study also examined the Arizona network and described an ICER of $108,363 per QALY with a 3-month horizon and $2,449 per QALY with the lifetime horizon⁹. An additional study completed in Denmark revealed the program becomes more efficient with time. The Danish determined an ICER of $50,100 per QALY after a year, and the program became dominant (both cost saving and increased effectiveness) after 30 years³¹.

Unlike previous studies, the ACCESS project has been shown to dominate in the 3-month horizon. The increase in effectiveness stems from increased usage of tPA, the large cost savings from the decrease in unneeded transports, and better patient outcomes that resulted in less need for hospital intervention.

Limitations/future models

One of the major limitations of this study is that the results are only valid if the assumptions hold, as it is with most cost-effective analysis (CEA) studies. Our CEA is limited by the current literature data and the present state of our experience with our teleneurology program. Conservative assumptions were made under uncertainties. For example, the study assumed no differences in subsequent care and outcomes following the initial hospitalizations; however, if a patient receives treatment in a teleneurology program, they may also receive better quality of subsequent care33, which could affect their final outcomes. These assumptions lead to increased reliability with limited and imperfect data. Also, our analysts used current national averages for costs and outcomes when in reality these vary from region to region. While the sensitivity analysis could address part of this concern, it cannot address the full range of possible program aspects. Once more prospective data is available, our assumptions can be addressed, and the model can be compared to the real data. Lastly, it was assumed that diagnosis had the same accuracy for both those in the program and those outside the program.

Future work in this area should focus on the impact of the availability of teleneurology consultations on the treatment of hemorrhagic stroke, transient ischemic attacks (TIA), and stroke mimics. While there have been a few studies, there is still much to add to the literature^34–36. A model exploring the long-term effects of the program will need to be developed in order to address the accuracy of initial diagnosis, the reduced cost of long-term treatment, and long-term QALY. Also, the influx of revenue to the rural hospitals will have spillover effects. These spillover effects should be studied further.

Finally, the decision process at rural hospitals has recently been altered by the introduction of a new treatment for large vessel occlusion. This treatment demands rapid identification of a relatively small, but significant sub-set of patients. These patients benefit from rapid access to intra-arterial therapy. Because this type of life-saving treatment is only available at hospitals providing immediate access to interventional therapy, more patients are currently being transferred for this type of intervention. Intra-arterial therapy was not looked at in this study, as the number of observations was too small at the time. Future work will address this. This new indication for transfer may impact the observations made in this study. The current and future indications for the optimum treatment for ischemic stroke will need continued study to fully understand their clinical and financial implications.

Conclusion

The teleneurology program ACCESS is a cost-effective approach to managing patients with neuro-emergent conditions in rural areas. In addition to providing financial benefits, a teleneurology program produces better patient outcomes, and offers societal benefits through reduction of stroke-related disability and increased convenience to patient’s families. It also limits the economic drain from rural hospitals by reducing the necessity for transport to an urban tertiary care facility. Further study is needed to examine the effects of a teleneurology program on patients with hemorrhagic stroke, TIAs, or stroke mimics.

Transparency

Declaration of funding

This publication was made possible by Grant Number 1C1CMS331351 from the Department of Health and Human Services, Centers for Medicare & Medicaid Services. The contents of this publication are solely the responsibility of the authors, and do not necessarily represent the official views of the US Department of Health and Human Services or any of its agencies. The research presented here was conducted by the awardee. Findings might or might not be consistent with or confirmed by the findings of the independent evaluation contractor.

Declaration of financial/other relationships

The authors are employees of the University of New Mexico. Peer reviewers on this manuscript have received an honorarium from JME for their review work, but have no other relevant financial relationships to disclose.

Notice of correction

Please note that Figure 2 has been amended since the paper was first published online (19 January 2018).

Acknowledgments

No assistance in the preparation of this article is to be declared.

Notes

Notes

1 The total number of possible outcomes is 56.

2 While the standard of care for tPA is the 3-h mark, some studies have shown effectiveness of tPA up to the 4.5-h mark. Additional analysis was done, moving the time of a stroke specialist reading a patients CT/MRI imaging from 3-h to 4.5-h. These results were similar, with slightly greater cost savings.