In the Unlikely Event: Optimal Care Strategies for Stroke in the Cath Lab

As a result of advanced technology and science, stroke is now the fifth-leading cause of death in the United States, killing more than 130,000 Americans each year at a toll of $33 billion annually. It is also the leading cause of disability in the United States. 
May is National Stroke Month, sponsored jointly by the American Heart Association and American Stroke Association, which lends support to the strategic and operational linkage between cardiac programs and stroke care.  Not only are the risk factors for stroke very similar to those for coronary disease, but patients who undergo cardiac interventions for coronary disease have a periprocedural risk for stroke.  

Though the overall complication rates for cardiac catheterization and percutaneous coronary intervention (PCI) are low, periprocedural stroke affects thousands of patients each year. The incidence of stroke during and after diagnostic cardiac catheterization ranges from 0.11% to 0.4%; stroke during or after PCI ranges from 0.18-0.44%. The incidence of cerebral hemorrhage specifically after PCI is 0.2-0.3%. 

Patients who experience a stroke during or after diagnostic cardiac catheterization or PCI will likely have an increased length of stay by approximately four days, and experience moderate to severe disability post discharge. The in-hospital mortality rate ranges from 25-44%. If PCI is performed in case of an acute coronary syndrome (ACS), the overall risk of stroke and complications increase further. 

Statistics show that, although rare, strokes do occur in the cardiac cath lab, making it necessary for the staff to be able to recognize the signs and symptoms of a stroke, along with knowing the immediate actions to take in order to prevent suboptimal outcomes. Corazon recommends that such training be included for all cath lab team members, as having the ability to recognize a stroke and being able to immediately intervene can significantly improve the long-term outcomes. 

Therefore, identifying patients at high risk, and understanding the symptoms and treatment possibilities for stroke is very important. Raising the level of awareness of the cardiac cath lab staff and having clear protocols in place to address recognition and intervention regarding stroke can facilitate staff comfort and efficiency in the unlikely event of a stroke in the cath lab.  

Invasive cardiac procedures carry additional ingrained risks, even though the risk factors for cardiovascular disease and cerebrovascular disease are very similar, which means the cath lab team must be aware of their hospital’s protocol in the event that a PCI patient would suffer a stroke during or after their procedure. Patients at higher periprocedural risk for stroke are those with:

• Advanced age
• Female gender
• History of stroke
• Renal failure
• Diabetes mellitus
• Arterial hypertension
• Peripheral vascular disease
• Dyslipidemia
• Tobacco use
•  Atrial fibrillation
• Previous myocardial infarction
• Congestive heart failure
• Left-sided valvular disease
• Poor left ventricular systolic function
• Prior coronary artery bypass graft surgery
• No or irregular use of needed antiplatelet medications 
• Depressed ejection fraction
• PCI done under emergent conditions and the use of an intra-aortic balloon pump

Corazon encourages education for cath lab staff, ensuring that they are aware of these and other possible risk factors. Education can assist the staff and provide to them the tools needed to identify patients who are at high risk for experiencing a stroke and enable them to take the appropriate actions to help prevent/minimize the possibility of any adverse events.

The symptoms seen with a stroke are dependent on the location of the infarct or hemorrhage. In the general population, 80-90% of emboli result in a stroke that affects the anterior cerebral circulation. In the cardiac catheterization population, however, greater than 50% of the emboli affect the vertebrobasilar circulation. Approximately 20% of the cerebral blood flow travels through the posterior circulation and even very small emboli can cause significant neuro deficits. Symptoms of vertebrobasilar circulation disruption include facial paresthesias, dysphagia, dysarthria, hoarseness, hemisensory extremity symptoms, motor weakness, diplopia, and sudden sensorineural hearing loss.

Common neurological deficits seen during a stroke in the cath lab are motor weakness, aphasia, changes in mental status and visual disturbances, with the most common being motor or speech deficits. Stroke symptoms can be difficult to identify because they are camouflaged by or mimic the effects of sedation. In addition, other conditions such as seizures, hypoglycemia, and migraine can mimic stroke symptoms.

Offering education in various forms can enhance the staff’s ability to retain the information. Periodic reviews, placement of a poster, and/or competency assessment can increase staff awareness and accurate diagnosis of the signs and symptoms of stroke. The goal should be to focus on the neuro exam in the cardiac cath lab, targeting the assessment and identification of these particular signs and symptoms. Rapid discovery of a stroke and prompt intervention may minimize any long-term effects of the stroke or even save the life of the patient.

Infarcts during catheterization and intervention can occur from various embolic sources. The composition of the emboli also varies, from air to soft clot to calcified atheroma, or multiple compositions such as atheroma with a fibrin clot around it.

Emboli can be the result of various processes; large injections of air into the circulation down to gaseous microemboli that are due to microbubbles injected with contrast or saline can produce air emboli. Transcranial Doppler (TCD) studies have shown multiple cerebral microemboli released during cardiac catheterization. The exact incidence of air emboli is unknown and there are no specific neurological signs or symptoms related to air embolism.

Larger guide catheters are used in PCI, plus more and stiffer-caliber catheters than are used in diagnostic catheterizations. This raises the risk of trauma to the aorta and the dislodgement of aortic atheroma during catheter manipulation. Emboli can also result from a thrombus which has formed within the catheter or catheter tip during the procedure. There is a question regarding the relevance of upper extremity versus lower extremity access sites, and the risk of aortic atheroma. The transradial approach to catheterization is thought to lead to a higher number of solid emboli due to mechanical forces near the apertures of the right vertebral and common carotid arteries; plaques in those areas risk becoming dislodged and embolizing to the brain.

Asymptomatic infarcts (i.e.,“silent” ischemic events) are not reflected in the statistics quoted for periprocedural stroke. Deficits may not exist or not be noticeable, such as some mild cognitive deficits. Since patients are not tested for these deficits, the impact on quality of life is uncertain, as are the long-term effects. It is estimated that asymptomatic cerebral infarction after cardiac catheterization has an incidence of approximately 15%.

Having the ability to recognize the cause and type of the infarct can assist in determining the treatment and interventions that are needed to produce the most beneficial outcomes for the patient, thus preventing the risk of secondary stroke occurrence. 

The brain has a limited ability to reserve oxygen, making it unable to withstand an ischemic event for any length of time without permanent deficits. For this reason, it is extremely important to provide immediate interventions as soon as possible when signs and symptoms of a stroke are detected. Patients who present to the emergency department (ED) with stroke symptoms should have treatment initiated within 60 minutes. The same time limit should be adhered to in the cardiac cath lab as well with the discovery of symptoms.

Clear standards, based on best practice, must be in place and delineated to the staff that define the stroke protocol process in the cardiac cath lab.   

Corazon recommends that the cath lab set up a stroke alert process (Figure 1) that would ensure a rapid response to a necessary stroke intervention within the cath lab setting.  

Issues that should be addressed include:

• Who should respond to the stroke code, (e.g., neurologist, neurological interventionalist, pharmacist [if t-PA is not readily available or the staff is not familiar with preparing and administering it], etc.)
• Who activates the alert process that notifies the responders
• The roles of the individual cath lab team members
• Actions to be taken and in what sequence

Based on Corazon experience with diverse programs across the country, typically, the personnel to notify during a stroke alert activation are:

• CT technician: To ensure availability of the scanner. Protocol usually dictates that the technician will finish the current patient and then hold the scanner open for the incoming stroke patient.
• Laboratory: As soon as the blood specimen is brought to the lab, the specimen will be run through the next batch of blood work and the results reported back to the cardiac cath lab as soon as possible.
• Neurologist: To verify the instance of stroke, and to help develop an optimal and timely treatment plan.
• Pharmacy: To verify dosage of weight-based tPA, mix necessary drugs and deliver them to the CCL.
• ICU: Because the patient will require an ICU bed if tPA is administered or a mechanical intervention is performed.  

The stroke team responders should be notified when the symptoms are evident and the patient will require assessment for critical deficits. Assessment includes vital signs and basic neuro exam at least every 15 minutes, and performing the National Institutes of Health Stroke Scale (NIHSS) (Figure 2). 

The NIHSS is critical in determining baseline deficits and in assisting the staff to determine the patient’s candidacy for thrombolytic intervention. The symptoms must be confirmed as the result of stroke, and other possible neurological events need to be ruled out, such as seizures or brain tumor. Either a CT or MRI can confirm a stroke, though CT is usually the diagnostic test most readily available. The procedure catheter can remain in place for the CT if there is a potential to use it for an intra-arterial lytic intervention. Also, if the sheath is still in place, a cerebral angiogram can be performed in lieu of the CT scan. An angiogram will better determine thrombus morphology, the location and degree of the occlusion, and the status of collateral circulation, when compared to CT. Also, the sheath can provide access for mechanical retrieval of the occluding material if necessary.

Selective intra-arterial treatment may be preferred if the patient has recently received antiplatelets and anticoagulants, which would increase the risk of bleeding. Since there is a lesser dose of drug administered, the risk of bleeding should be decreased.
Once the stroke is determined via CT and an infarct differentiated from a hemorrhage, a consulting neurologist can assist in determining the benefits/risks ratio and develop a treatment plan. A neuro interventionalist can perform the angiogram or the intravascular interventions, if necessary. If the CT suggests an infarct, the tPA inclusion/exclusion criteria list should be reviewed (Figure 3). If the patient meets the criteria for intravenous tPA, the drug should be started immediately.

tPA dosage is weight-based at 0.9 mg/kg to a maximum of 90 mg. The drug is mixed in sterile water and should not be shaken or sent through a pneumatic, which would destroy some of the product. It is given in two stages: 10% of the total dose is given through a dedicated IV line over one minute, with the remaining 90% of the dose given over 60 minutes via IV infusion pump. tPA preparation should be started as soon as possible, since it takes several minutes to mix. 

Vital signs and neuro exams should be performed every 15 minutes for two hours, every half hour for six hours, followed by every hour for the next 16 hours. The patient should be admitted to an intensive care unit to monitor for neurological changes and complications due to the tPA. 

The interventionalist will determine the dosage of intra-arterial tPA, which will be administered at a lesser dose. If the patient is not a candidate for either intravenous or intra-arterial tPA, mechanical extravasation of the embolus or multimodal endovascular therapy may be considered.

Complications with tPA administration can occur. The critical complications that can occur with tPA are intracranial bleeding, systemic bleeding, and angioedema, all of which require immediate intervention. The incidences of complication are 6%, 2%, and 5%, respectively. During or shortly after cardiac catheterization, retroperitoneal bleeding and groin hematoma can also occur. If the sheath is in place during lysis, leaving it in place for several hours after tPA infusion helps to minimize the risk of bleeding. The risk of retroperitoneal blood loss from compressible access site is lower with intra-arterial than with intravenous tPA.

If the stroke is due to an intracranial hemorrhage, anticoagulation should be reversed and a neurosurgeon consulted to determine if any surgical intervention is indicated. If the cerebral embolism is due to air, 100% oxygen should be administered by face mask and the patient considered for hyperbaric oxygen therapy.

In conclusion, stroke is an uncommon but potentially devastating complication of cardiac catheterization, thus should be a key concern for cardiac program leaders. Stroke Month could be the catalyst for initiating the necessary training or education to ensure cath lab teams understand the stroke risk of their patients and know what to do in the unlikely event of a stroke.

Certainly, there are measures that can be instituted to assist in the prevention of the patient experiencing an ischemic stroke, including identification of the high-risk patient before the procedure, having the patient well hydrated prior to the procedure, using catheter techniques to minimize trauma, and judicious use of ventriculography.

Just as with a cardiac emergency, having processes in place to address a stroke event can facilitate positive patient outcomes and save lives. Indeed, Corazon strongly believes in clear, well thought-out policies, procedures, and processes that activate a stroke code when needed.  Initiating immediate patient assessment and intervention could minimize cerebral damage and facilitate positive long-term outcomes in the rare case of a cardiac cath lab stroke event.

Sources/Bibliography

1. Sankaranarayanan R, Msairi A, Davis GK. Stroke complicating cardiac catheterization—a preventable and treatable complication. J Invasive Cardiol. 2007; 19(1): 40-45.
2. Korn-Lubetzke I, Farkash R, Pachino RM, Almagor Y, Tzivoni D, Meerkin D. Incidence and risk factors of cerebrovascular events following cardiac catheterization. J Am Heart Assoc. 2013: (2): 1-8.
3. Werner N, Bauer T, Hochadel M, Zahn R, Weidinger F, Marco J, et al. Incidence and clinical impact of stroke complicating percutaneous coronary intervention: results of the Euro heart survey percutaneous coronary interventions registry. Circ Cardiovasc Interv. 2013 Aug; 6(4): 362-9. doi: 10.1161/CIRCINTERVENTIONS.112.000170.
4. Yanko J. Stroke and PCI: Best practice in the cardiac cath lab. Cath Lab Digest. 2012: 20(7). Available online at https://www.cathlabdigest.com/articles/Stroke-PCI-Best-Practice-Cardiac-Cath-Lab. Accessed April 18, 2017.
5. Hickey JV. The Clinical Practice of Neurological and Neurosurgical Nursing. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins; 2014.  
6. Stroke Facts. Centers for Disease Control and Prevention. Available online at https://www.cdc.gov/stroke/facts.htm. Accessed April 17, 2017.

Mona Steinbeiser is a Consultant with 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 msteinbeiser@corazoninc.com.