A Newly Demonstrated Safe Approach: The Rationale for Intravenous rtPA Used in Acute Stroke Patients with an NIHSS of 5 or Less

Rhonda Long is a Director at Corazon, Inc., offering strategic program development for the heart, vascular, neuro, and orthopedic specialties. Corazon provides a full continuum of consulting, software solution, recruitment, and interim management services for hospitals, health systems, and practices of all sizes across the country and in Canada. To learn more, visit www.corazoninc.com or call (412) 364-8200. To reach the author, email rlong@corazoninc.com.

As catheterization procedural volumes increase and the population ages, Corazon believes that preparation in the cath lab for an increased frequency of stroke is warranted. A cardiac catheterization laboratory team practiced in the immediate actions and treatment necessary in the event of a stroke offers their patient the best chance to prevent and/or reduce any possible disability occurring as a result of a stroke. 

Though infrequent, stroke does occur in the cardiac cath lab. Catheterization across a degenerated aortic valve may lead to thromboembolism and the risk of stroke may be particularly high in patients with significant valvular aortic stenosis who undergo retrograde catheterization of the aortic valve.^1,2 Patients may experience either ischemic or hemorrhagic stroke in the setting of cardiac catheterization. The cardiovascular team should be practiced in assessing for stroke and skilled at quickly recognizing a stroke in the context of their procedural focus. 

May is American Stroke Month, a good time to examine one of the relevant stroke treatment topics with a newly demonstrated safe treatment rationale, important to both cardiovascular and neuroscience programs across the country. A recent study  by Romano et al, published in JAMA Neurology³, examined a cohort of the American Heart Association (AHA) Get with the Guidelines (GWTG) Stroke Registry, revealing important information that impacts the care of mild acute ischemic stroke patients. 

AHA GWTG Stroke Registry data 

The AHA GWTG Stroke Registry, powered by Quintiles, has become a rich resource in both data elements and case volumes. The registry is a highly structured database with tight levels of data controls. Stroke coordinators and hospital stroke teams across the nation regularly contribute detailed information on their individual acute stroke cases, creating retrospective opportunities for research, benchmarking, and quality improvement. 

Within the AHA GWTG Stroke Registry, Romano et al evaluated 33,995 cases (patients discharged between May 2010 through October 2012) to ultimately define a cohort of 5,910 mild acute ischemic stroke cases containing the following: admittance within 4.5 hours of symptom onset, administration of intravenous tissue plasminogen activator (IV rtPA), and the presence of a complete data set for analysis. Evaluated complications from administration of IV rtPA were symptomatic intracranial hemorrhage, life-threatening or serious systemic hemorrhage, other serious complications, and undetermined complications. At discharge, evaluation of short-term outcomes included in-hospital mortality, discharge to home, independent ambulation at discharge, and length of stay. This study focuses on mild acute ischemic strokes that can occur during semi-elective and emergent procedures such as a diagnostic cardiac catheterization, percutaneous coronary intervention, and ablations. 

NIHSS to evaluate stroke

The National Institutes of Health Stroke Scale or NIH Stroke Scale (NIHSS) is a tool used by healthcare providers to objectively quantify and succinctly communicate the impairment caused by a stroke (Figure 1). The NIHSS is composed of 11 items, each of which scores a specific ability between 0 and 4. For each item, a score of 0 typically indicates normal function in that specific ability, while a higher score is indicative of some level of impairment. The individual scores from each item are summed in order to calculate a patient’s total NIHSS score. The maximum possible score is 42, with the minimum score being 0.

Patients presenting as potential “stroke mimics” often comprise a subgroup of patients with lower NIHSS scores. However, determining actual strokes vs stroke mimics can be a difficult task, even for a seasoned clinician. As stroke affects younger individuals, many clinicians erroneously believe that stroke symptoms must actually be a mimic. Even though stroke mimics impact zero volume of brain density and have an even lower risk of complications from IV rtPA than with minor strokes where a small density of brain volume is affected, this group is not often given IV rtPA.   

“Small” deficits can lead to big disabilities 

Currently only about one in five patients treated with IV rtPA have an NIHSS of 5 or less. The NIHSS has been found to be an excellent predictor of patient outcomes. A baseline NIHSS score greater than 16 indicates a strong probability of patient death, while a baseline NIHSS score less than 6 indicates a strong probability of a good recovery. However, with increasingly influential baby boomers redefining their retirement years as an active and highly contributing phase of life, their ability and function is paramount — meaning what has been previously considered a “good” stroke recovery is often not enough. Synergy is occurring, fortunately, with improved treatment options and increased access to care options, as well as better management of the risk factors for stroke. Compounding this dyad of redefining a “good” recovery and improving management of risk factors is the improvement in recognition of the occurrence of an acute stroke. Collectively, the resulting hope is that percentages of acute stroke patients with minor strokes (vs major strokes) will increase, while the percentages of total strokes in the “at risk” population will decline.  

How will we approach hyper-acute treatment in this population of minor strokes going forward? 

Rapid assessment of stroke severity should be targeted to reduce delay of IV rtPA treatment. Some hospitals use an NIHSS of less than 5 to exclude patients from IV rtPA treatment; however, the AHA urges against NIHSS scores being used as the sole reason for declaring a patient ineligible for IV rtPA treatment. 

The cath lab team would likely employ a process to call a stroke alert in the event of any single acute stroke symptom. The stroke alert team receives the cath lab team’s stroke assessment and performs additional assessments moving forward. While having select cath lab personnel certified in the NIHSS is a best-practice approach, all cath lab personnel should be competent in basic stroke assessments like The Cincinnati Stroke Scale, F.A.S.T, or The Suddens. If your hospital or facility does not have a stroke alert team, cath lab professional personnel and physician providers should not only be certified in the NIHSS, but also competent to initiate immediate treatment for an acute stroke. 

Corazon consultants work regularly with hospitals to fully understand and embrace evidence-based concepts, including modifying protocols to support consideration of eligibility for IV rtPA treatment in cases with an NIHSS of 5 or less. In Corazon’s diverse experience working with hospitals in 43 states, we see significantly less attention given  to the consideration and actual use of thrombolysis (IV rtPA) in this group of acute minor stroke patients. A frequently cited reason for hesitancy in administering IV rtPA is risk of a serious complication like cranial hemorrhage and risk of litigation. Change is difficult. Yet the findings by Romano et al further support the move to administering IV rtPA in an acute minor stroke. 

To better envision this type of patient, consider the following example of the neurological deficits in an acute stroke patient presenting with an NIHSS total of 4 (traditionally considered too low a score for IV rtPA):

• Score of 2 in motor arm: Limited effort against gravity; the right arm is able to obtain the starting position, but drifts down from the initial position to a physical support prior to the end of the 10 seconds; (PLUS)
• Score of 2 in language: Severe aphasia; all speech is fragmented, and examiner is unable to extract the figure’s content (on a standardized picture card) from the patient’s speech.

Indeed, these are serious deficits, though the NIHSS score is low. While the one-year post stroke disability for this patient may not be as high as the initial NIHSS assessment of 4, there is a demonstrated safe and best chance of complete recovery with the use of IV rtPA — if other absolute exclusion criteria to administering the IV rtPA are absent, such as current intracranial hemorrhage or active internal bleeding. This level of deficit would be considered a life-altering disability among the many individuals that currently define quality of life as being active, with a high level of contribution to the wellbeing of their families and communities, and the ability to maintain self-care. 

Outcome 

The most feared complication associated with giving IV rtPA is symptomatic or life-threatening intracranial hemorrhage. Among the 5,910 cases analyzed by Romano et al in the GWTG Stroke Registry study³, treatment complications with IV rtPA were 1.8% or lower, with the exception of complications of undetermined cause, which were 2.4%. Mortality was 1.3%. In examining quality of life or activity function, roughly 30% of the study cohort was not fully functioning at discharge. This was assessed by short-term outcomes including discharge dispositions other than to home and lack of independent ambulation. 

Impact on practice and stroke programs

Potential opportunities to administer IV rtPA existed in an additional 26,374 (77.6%) patients from the study’s initial full cohort (n=33,995) of those patients arriving within 4.5 hours of acute onset and assessed with an NIHSS of 5 or less. Additional analysis is needed to understand the reason or contraindication for not administrating IV rtPA in these 26,374 patients. The data evaluated in this study provide reassurance that rtPA can be safely administered in the minor stroke population, though as with most good studies, more questions will no doubt surface. The authors conclude that more research is needed to improve the quality of life outcomes in patients with minor stroke, including those in which IV rtPA treatment was utilized.        

In light of this new and convincing data demonstrating the safety of IV rtPA for a larger group of stroke patients, Corazon strongly advises an assessment of your hospital’s current policy on inclusion or exclusion criteria specific to initial NIHSS scores of 5 or less, regardless of where the stroke “presents” (the emergency department, in-house in the cardiac cath lab, or elsewhere). Indeed, an educational focus on this topic will empower clinical providers in any area to launch discussion around this treatment option during the window of hyper-acute care, as well as during retrospective case review on all stroke patients presenting within 4.5 hours of symptom onset. 

Corazon recommends presenting actual cardiovascular and cath lab stroke cases from within the organization or system, or even cases available in the literature^4-6, as a highly effective approach to engaging cardiac cath lab professionals on the topic of stroke — and not just in May, but throughout the year. Including the cardiovascular case overview and the stroke presentation, treatment, and outcome promotes learning through real-life examples.

References

1. Omran H, Schmidt H, Hackenbroch M, Illien S, Bernhardt P, von der Recke G, et al. Silent and apparent cerebral embolism after retrograde catheterization of the aortic valve in valvular stenosis: a prospective, randomized study. Lancet. 2003; 361(9365): 1241-1246.
2. Chambers J, Bach D, Dumesnil J, Otto C, Shah P, Thomas J. Crossing the aortic valve in severe aortic stenosis: no longer acceptable? J Heart Valve Dis. 2004 May; 13(3): 344-346.
3. Romano JG, Smith EE, Liang L, Gardener H, Camp S, Shuey L, et al. Outcomes in mild acute ischemic stroke treated with intravenous thrombolysis: a retrospective analysis of the get with the guidelines-stroke registry. JAMA Neurol. 2015 Apr 1; 72(4):423-431. doi: 10.1001/jamaneurol.2014.4354.
4. Chan AW, Henderson MA. Immediate catheter-directed reperfusion for acute stroke occurring during diagnostic cardiac catheterization. Catheter Cardiovasc Interv. 2006 Feb;67(2):314-318.
5. Serry R, Tsimikas S, Imbesi SG, Mahmud E. Treatment of ischemic stroke complicating cardiac catheterization with systemic thrombolytic therapy. Catheter Cardiovasc Interv. 2005 Nov; 66(3): 364-368.
6. Chen YW, Sim MM, Smith EE. Thrombolytic therapy in acute cerebral infarction complicating diagnostic cardiac catheterization. J Formos Med Assoc. 2006 Oct; 105(10): 848-851.

Further reading from Cath Lab Digest and the Journal of Invasive Cardiology

Kern M. Your patient can’t talk after the cath — what to do with a stroke in the cath lab. Cath Lab Digest. 2008 July; 16(7). Available online at https://www.cathlabdigest.com/articles/Your-Patient-Can%E2%80%99t-Talk-After-Cath-%E2%80%93-What-Do-With-a-Stroke-Cath-Lab. Accessed April 21, 2015.

Yanko J. Stroke and PCI: best practice in the cardiac cath lab. Cath Lab Digest. 2012 July; 20(7). Available online at https://www.cathlabdigest.com/articles/Stroke-PCI-Best-Practice-Cardiac-Cath-Lab. Accessed April 21, 2015.

Sankaranarayanan R, Msairi A, Davis GK. Stroke complicating cardiac catheterization — a preventable and treatable complication. J Invasive Cardiol. 2007 Jan; 19(1): 40-45. Available online at https://www.invasivecardiology.com/articles/stroke-complicating-cardiac-catheterization-%E2%80%94-preventable-and-treatable-complication. Accessed April 21, 2015.