Management of blunt cerebrovascular injuries at a Canadian level 1 trauma centre: Are we meeting the grade?

Discussion

In this retrospective single-centre review of management of patients with BCVIs, antithrombotic management was in keeping with current recommendations. However, there was considerable variability in follow-up care plans in this patient population. This is an identified opportunity to harmonize follow-up vascular imaging and multidisciplinary clinical care by developing a treatment pathway combining in-hospital and outpatient best practices.

Guideline-facilitated diagnosis of BCVI relies on the implementation of screening criteria to identify patients at high risk needing further evaluation with gold-standard diagnostic imaging, namely, CTA of the cervical carotid and vertebral arteries. The recent extension of the Denver screening tool to include all patients with cervical spine fractures and upper rib fractures was particularly relevant in the present study, as these injuries were among the most common Denver criteria present in our patient population. However, given that 18 patients had brain infarcts on initial imaging (presumably secondary to their concurrent BCVI, given that no patients had infarcts determined to be long-standing and thus likely to have preceded the injury), it could be argued that all patients with major blunt mechanisms should have vascular imaging as part of their baseline radiologic assessment.14 Concerns about unnecessary radiation exposure and overtriaging are arguments against adopting such a liberal screening strategy. However, given the finding that BCVI is associated with new ischemic events early after presentation,6 together with evidence from the non–traumatic stroke literature that abnormal vascular imaging is associated with risk of recurrent ischemic events within the first 24 hours after presentation,15 recognition of BCVI and prompt initiation of antithrombotic treatment could potentially further reduce the risk of later BCVI-associated stroke.

In the present study, the majority of eligible patients were prescribed ASA monotherapy or therapeutic low-molecular-weight heparin during their hospital course. However, antithrombotic treatment was initiated within 24–48 hours in only 90% of those without contraindications to treatment.8 The strong preference for ASA over low-molecular-weight heparin is reflective of local practice patterns, with anticoagulation being reserved for patients with BCVI with intraluminal thrombus (although there is an absence of evidence in the literature to support this strategy). Other non–guideline-aligned strategies included use of unfractionated heparin, in some cases with bridging to warfarin. Although therapeutic reasoning was not documented consistently, the use of unfractionated heparin, which can be stopped and reversed, over low-molecular-weight heparin may reflect practitioner concerns with regard to bleeding risk. The prescribing of warfarin reflects the practitioner’s preference for longer-term anticoagulation, to be reassessed in the outpatient setting.

There were minor variations between stroke care provider recommendations, with very few patients receiving a loading dose of ASA before initiation of daily low-dose ASA. There is evidence from the non–traumatic stroke literature suggesting that the practice of giving a baseline loading dose of ASA is associated with improved outcomes,16 and good evidence that early initiation of dual antiplatelet therapy with ASA and clopidogrel, or ASA and ticagrelor is superior to ASA alone for secondary prevention.17^–19 However, the value of these strategies for stroke prevention in the BCVI population is unknown.10 In the present study, stroke care providers more often recommended higher initial dosages of ASA or dual-antiplatelet therapy in patients with higher-grade injuries, which suggests extrapolation from the nontraumatic stroke literature with higher-risk BCVI grades. Four patients had strokes while receiving ASA monotherapy. All had polytrauma with higher-grade injuries, and, thus, it is possible that more aggressive antithrombotic therapy was precluded owing to concerns about bleeding risk.

In our cohort, there were 30 patients who had concomitant injuries delaying or preventing antithrombotic treatment, nearly one-quarter of whom developed a new infarct. This group illustrates a therapeutic dilemma in the management of patients with BCVI with concomitant brain or solid-organ injuries, namely, balancing the benefits of stroke prevention against the risks of bleeding. Recent evidence suggests that antithrombotic treatment in such cases does not increase the risk of bleeding complications, including new or worsening intracerebral hemorrhage.10^,20 Further discussion is warranted among trauma specialists and neurosurgeons to clarify patients at higher risk in whom early antithrombotic therapy may still be cautiously initiated.

Recommendations for repeat imaging at 7–10 days and at 3 months are clearly outlined in the clinical guidelines as a means of ruling out false-positive findings on initial CTA, and examining vessel healing and determining duration of antithrombotic therapy.1^,7^,8 At our centre, only one-third of patients had repeat imaging within 7–10 days, and more than one-quarter did not have any repeat imaging. Since these follow-up investigations help to guide duration of antithrombotic therapy, consistent follow-up could reduce the likelihood of late bleeding complications associated with prolonged antithrombotic therapy.21 Some physicians opted to repeat CTA at 1 month and 3 months instead of 7 days. There is no clear evidence to suggest that the alternative time frame is inferior; however, evidence suggests that repeat imaging at 7–10 days, especially in patients with low-grade injuries, often changes management.22 In addition, a potential cause of the suboptimal rates of repeat imaging is the lack of appropriate documentation of the treatment algorithm in 29% of discharge summaries. In British Columbia, the challenge of accessing neuroimaging and outpatient services from remote communities underscores the need for clear communication to general practitioners responsible for the follow-up care of patients with trauma.

Our findings identify 2 meaningful targets for improvement, both requiring a collaborative multidisciplinary effort between the trauma and neurology services. First, antithrombotic therapy should be initiated within 24–48 hours of diagnosis in patients with isolated BCVIs.8 In patients with concomitant traumatic brain or solid-organ injuries, multidisciplinary discussion is needed to determine which patients may safely tolerate more aggressive timelines for initiating antithrombotic treatment. Second, there is a need for a routine pathway that arranges appropriate follow-up imaging and clinical follow-up to facilitate decision-making regarding duration of antithrombotic treatment, with clear associated documentation and communication on hospital discharge.

Adherence to practice guidelines can be improved. This may be achieved through multidisciplinary education to promote awareness of BCVI management guidelines, and the development of a treatment pathway and preprinted order set that initiates evidence-based patient care and recommendations to ensure a clearer trajectory through the hospital system for patients with BCVIs. The creation of this algorithm at our institution will require a holistic approach that involves engagement and commitment of relevant leaders from trauma surgery, neurology, radiology, primary care and allied health services. Last, given possible regional differences in the management of patients with BCVIs across trauma systems in Canada, further research and consensus statements to standardize and guide the care of this vulnerable population are required.