Acute Stroke Management during pregnancy :Canadian Consensus Statement

There is an increased risk of stroke during pregnancy and a cause of death and disability for women. The Canadian Stroke Best Practice Consensus Statement Acute Stroke Management during Pregnancy is the second of a two-part series devoted to stroke in pregnancy. This document was developed in recognition of the need for a specifically tailored approach to the management of this group of patients in the absence of any broad-based, stroke-specific guidelines or consensus statements, which do not exist currently. The 2018 Canadian Stroke Best Practice Consensus Statement on acute stroke management during pregnancy focuses on the management of a woman who experiences an acute stroke during pregnancy and it provides clinicians with guiding principles to manage all such women.

Key Consensus Statements are:

Diagnostic imaging

• i. Counseling of pregnant patients on imaging-associated risk for both mother and fetus may be considered and coordinated between clinical and imaging teams.Note: Many clinicians remain overly concerned about the fetal risk associated with neuroimaging and ionizing radiation (CT). The fetal dose of radiation, and corresponding risk, associated with neuroimaging is extremely small.


• ii. Where an acute stroke is suspected, given the severe maternal risk caused by potential delay in diagnosis when compared to the minimal risk to the fetus with CT imaging, it is acceptable to conduct a CT scan of the head without first establishing pregnancy.
  
  
  
  • a. For severe disabling stroke, standard of care for the diagnosis of acute stroke includes immediate imaging of both the brain and cerebrovascular system, within minutes of hospital arrival.
    
    
    
    •    Note: in patients displaying mild or transient stroke symptoms who are not being considered for emergent stroke intervention, brain imaging and vessel imaging should still be undertaken in accordance with timelines as defined in CSBPR Acute Stroke Management section 2.
    
    
    
    
  
  
  • b. In most centers, this is achieved with immediate CT with CT angiography (CTA) of the head and neck. In some cases, CT Perfusion (CTP) or MRI may also be used to identify potential candidates for intravenous thrombolysis with alteplase and/or acute endovascular thrombectomy. Both CTA and CTP use intravenous contrast and have higher doses of radiation than a CT head.
  
  
  • c. In the time-sensitive emergency of severe disabling stroke, the health of the mother is paramount and CT with contrast is often the most accessible option to determine if patients are eligible for acute endovascular thrombectomy.
    
    
    
    • • Where immediately available as part of a local acute stroke protocol, MRI of the brain with time-of-flight (non-contrast) imaging of the blood vessels may be used in place of CT/CTA to visualize the brain and vasculature (Refer to iii below).
    
    
    • • In select cases (e.g. presence of a hyperdense middle cerebral artery on non-contrast CT), CTA may be deferred in a pregnant woman in favor of moving directly to digital subtraction angiography for potential treatment of a proximal occlusion appropriate to explain the symptoms.
    
    
    
    
  
  
  • d. Based on currently available evidence, the ionizing radiation associated with non-contrast CT head in pregnant patients does not expose the fetus to the high levels of radiation associated with increased risks of abortion, malformation, or other adverse pregnancy outcomes.
    
    
    
    • A typical CT of the mother's head carries a fetal radiation dose exposure of 0.001 mGy. The typical occupational limit for fetal radiation is 5 mGy. Therefore, the fetal exposure from a maternal CT head is 5000 times less than the allowable occupational exposure and carries negligible risks for fetal malformation, abortion, or other pregnancy complications when compared to the general risks of pregnancy.
    
    
    • A typical CT head exposes the fetus to a negligible amount of radiation. Owing to the distance of the mother's head away from the uterus, there is a low amount of scatter and minimal fetal exposure.
    
    
    • If CT scanning is used, efforts to minimize radiation exposure such as shielding of the abdomen/pelvis and minimizing extra scans are encouraged.
    
    
    
    
  
  
  • e. There is a lack of available evidence on any known harm identified in human or animal studies of exposure to CT contrast dye.
    
    
    
    • For breastfeeding, less than 1% of CT contrast dye is excreted in breast milk; of that, less than 1% is absorbed in infant gastrointestinal tract. Continuation of breastfeeding after exposure to CT contrast dye is reasonable.
    
    
    
    
  
  
  
  


• iii. MRI, without gadolinium, does not expose the mother or fetus to ionizing radiation. When appropriate and available, and where the results can assist in clinical decision-making, MRI is therefore a reasonable option in pregnancy. However, in many centers, MRI is not readily and rapidly available; in the setting of disabling acute stroke, the most available imaging modality should be utilized to avoid delaying treatment.
  
  
  
  • a. Time of flight imaging modalities (non-contrast MR angiography or venography) can often provide sufficient vascular information for emergency stroke decision-making in pregnancy and is preferred over contrast scanning.
  
  
  • b. MRI at 1.5 or 3.0 tesla (T) without gadolinium does not increase the risk of adverse fetal outcomes, whether exposure occurs in the first trimester or later.MRI of the fetus has been shown to be safe in the second and third trimesters.
  
  
  • c. Gadolinium exposure in the first trimester may be associated with an increased risk of adverse outcomes.Even outside of pregnancy, gadolinium is rarely needed in the setting of acute stroke diagnosis. Therefore, gadolinium is not recommended for stroke assessment in women with known pregnancy.
  
  
  
  


• iv. Institutional protocols on imaging in pregnancy and established methods for counseling pregnant women, or their next-of-kin, on risk/benefits and decision-making may be helpful to assist practitioners, especially in the time-sensitive setting of hyperacute stroke.
  
  
  
  • a. When possible, pregnant women should be wedged during supine imaging to allow for left uterine displacement, as of 24 weeks or when symptoms (e.g. lightheadedness) necessitate.
  
  
  
  

Acute ischemic stroke treatment: intravenous thrombolysis and endovascular treatment

Intravenous alteplase

• i. Acute stroke treatment decisions should be based on severity of symptoms, medical condition of the patient, and, when available, consideration of the personal values and wishes of the patient and her family or next-of-kin.


• ii. Treatment options for a pregnant woman with an acute stroke should promptly be considered in consultation with an interdisciplinary team with expertise in neurology, obstetrics and gynecology, maternal-fetal medicine, and interventional radiology, where possible and available.


• iii. Acute intravenous thrombolysis with alteplase has been shown to reduce morbidity in the non-pregnant population. There are a limited number of case reports published using alteplase during pregnancy.


• v. It is reasonable to consider giving IV alteplase to a pregnant patient with disabling ischemic stroke who meets existing criteria for thrombolysis. The risk–benefit considerations can be complex in the setting of pregnancy; thus, the decision should be undertaken in consultation with a physician with experience in acute stroke treatment either in person or through telestroke modalities.
  
  
  
  • a. While there are risks of hemorrhage (intracranial and otherwise) from intravenous alteplase, the decision to administer acute thrombolysis should be based on the maternal risks associated with the acute stroke.
  
  
  • b. Placental abruption can occur with or without alteplase, and it is not known whether alteplase increases the risk of abruption. Close monitoring and prompt recognition is important.
  
  
  • c. Alteplase is a large molecule (59,000 daltons) and does not cross the placenta.⁴³ Therefore, alteplase is not expected or known to pose direct intracranial or systemic bleeding risks to the fetus.
  
  
  • d. The safety and efficacy of intravenous alteplase in the early postpartum period (<14 days after delivery), especially related to risk of maternal postpartum hemorrhage, have not been well established.
    
    
    
    • • Case reports suggest that bleeding risk may be increased after alteplase administration and may be further increased if given following Cesarean delivery. Maternal risk of postpartum hemorrhage should be balanced with the risk of a thromboembolic event.
    
    
    • • The literature to guide assessment of risks from epidural or spinal anesthesia after alteplase administration is limited, but risks of bleeding complications may be increased.
    
    
    
    
  
  
  
  

3.2 Endovascular thrombectomy

• i. Pregnancy should not be considered a contraindication to angiography and endovascular thrombectomy (EVT) for proximal large vessel occlusions causing acute disabling stroke. These cases should be treated according to existing guidelines .
  
  
  
  • a. Efforts to avoid or reduce the risk of fetal injury such as abdominal shielding and judicious use of x-ray exposures are reasonable.
  
  
  • b. It is not reasonable to delay or defer necessary maternal care for severe disabling stroke secondary to the pregnancy. The acknowledgment of possible fetal risks is appropriate: risks may include radiation and contrast exposure, infections, and arterial puncture complications that could result in both maternal and fetal compromise. However, given the very high morbidity and mortality associated with acute ischemic stroke due to large vessel occlusions, these risks are generally outweighed by the benefits of treatment.
  
  
  
  

ii. For patients with large vessel occlusions eligible for and with rapid access to endovascular thrombectomy, proceeding directly to endovascular thrombectomy without administering intravenous alteplase could be considered.

For further reference log on to :

https://doi.org/10.1177/1747493018786617