Delayed thrombectomy for internal carotid artery occlusion in young stroke: a case report

Introduction

Background

Acute ischemic stroke in young adults is a growing clinical concern, presenting unique diagnostic and therapeutic challenges. Internal carotid artery occlusion (ICAO), while well-documented in older individuals with atherosclerosis, is rare in younger patients who often lack traditional vascular risk factors (1). In this population, ICAO is more frequently associated with non-atherosclerotic mechanisms such as arterial dissection, hypercoagulable states, or genetic predispositions. The clinical presentation may be subtle or transient, leading to potential delays in diagnosis and intervention.

Rationale and knowledge gap

Mechanical thrombectomy is the cornerstone of treatment for large vessel occlusion in ischemic stroke, with established benefits when performed within 6 to 24 hours of symptom onset. However, treatment decisions become more complex when young patients with ICAO present with mild or resolving symptoms (2). Current guidelines offer limited direction regarding intervention in such scenarios, particularly in cases of delayed neurological decline. There is a knowledge gap in determining when to escalate from conservative management to endovascular intervention in young patients who initially improve but remain at risk for infarct progression. This case also adds to the limited literature on intracranial internal carotid artery (ICA) dissections in young adults.

Objective

This report aims to illustrate the clinical decision-making process in a young adult with ICAO who was initially managed conservatively but later experienced neurologic deterioration, necessitating delayed mechanical thrombectomy. By sharing this case, we aim to highlight the importance of individualized treatment strategies and emphasize the potential benefit of intervention beyond conventional time windows, while acknowledging that functional recovery may remain incomplete and prolonged rehabilitation is often necessary. We present this article in accordance with the CARE reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-2025-136/rc).

Case presentation

A 24-year-old obese Hispanic male with no prior medical history presented with sudden-onset dizziness, right facial droop, and slurred speech that began during physical activity (playing soccer). He had no history of cardiovascular risk factors, smoking, alcohol use, or family history of stroke.

On initial examination, he exhibited mild dysarthria and a flattened right nasolabial fold. Strength and sensation were preserved. There were no signs of trauma, neck pain, or connective tissue disorder. He was not a candidate for IV thrombolysis due to non-disabling symptoms with National Institutes of Health Stroke Scale (NIHSS) score of 1. A non-contrast head computed tomography (CT) was unremarkable. CT angiography (CTA) showed a small hypodensity in the left parietal lobe, with no large vessel occlusion; therefore, endovascular stroke therapy was not pursued. Laboratory workup, including lipid panel, hemoglobin A1c (Table 1), was largely unremarkable except for borderline dyslipidemia and impaired glucose tolerance. A complete six-vessel diagnostic cerebral angiogram with three-dimensional rotational imaging demonstrated total occlusion of the left ICA, terminating in a stump at the posterior communicating segment. Just proximal to the occlusion, a supraclinoid stenosis was noted, raising concern for intracranial arterial dissection. When integrated with prior CTA findings, these features were most consistent with an acute to subacute dissection complicated by thrombosis of a false lumen. This finding supports dissection as the likely mechanism of stroke in this young patient who lacks atherosclerotic risk factors. Although these angiographic findings were suggestive of intracranial dissection with thrombosis of a false lumen, the diagnosis remained presumptive as confirmatory wall imaging and high-resolution magnetic resonance imaging (MRI) sequences were not performed due to the mild and non-progressive neurological deficits. Neurosurgery recommended conservative medical management and risk factor modification, and the patient was planned for an outpatient genetic and thrombophilia work-up (Table 2) to evaluate for underlying prothrombotic conditions. He was discharged on dual antiplatelet therapy (aspirin and clopidogrel) and a high-dose statin. The decision not to pursue earlier re-imaging was based on the patient’s initially mild and non-progressive neurological deficits, absence of recurrent symptoms during early outpatient follow-up, and conservative management consistent with current guidelines for low NIHSS score. At discharge, he was instructed to seek urgent medical attention should any neurological symptoms recur or worsen, but he remained stable until day 12, when new deficits prompted repeat imaging.

Twelve days post-discharge, the patient returned with new right-sided weakness and numbness. Non-contrast head CT and CTA showed asymmetric hyperdensity along the left first segment of the middle cerebral artery (M1) segment, concerning for intravessel thrombus. MRI revealed a new infarct in the left temporal lobe, and magnetic resonance angiography (MRA) (Figure 1) showed persistent ICAO with new middle cerebral artery (MCA) stenosis. He developed worsening right hemiparesis and aphasia. Both MRI and MRA did not confirm intracranial dissection. Repeat imaging revealed a large left MCA territory infarct with midline shift. Emergent mechanical thrombectomy of the left M1 segment was successfully performed.

Figure 1 Magnetic resonance imaging (A) and magnetic resonance angiography (B-D) of the brain shows hypo-intensity and loss of flow (red arrows) of the entire left ICA and left MCA suggestive of occlusion and high-grade stenosis in the left ICA and MCA. ICA, internal carotid artery; MCA, middle cerebral artery.

Post-thrombectomy, the patient received inpatient rehabilitation. At discharge, his NIHSS score was 8 and his modified Rankin Scale (mRS) was 3, reflecting moderate disability. At a 2-month follow-up, the patient was ambulatory with assistance but had persistent right hemiparesis and expressive aphasia. He completed physical therapy with all goals met and transitioned to independent home exercise. At 7 months, occupational therapy concluded after notable improvement in proximal right upper extremity control; however, spasticity continued to limit fine motor function. He remained independent in self-care using compensatory strategies. Speech therapy continues at 8 months, with marked gains in comprehension and single-word responses, though conversational ability remains significantly impaired. Rehabilitation potential remains good, with ongoing progress. Table 3 provides a timeline of the events. His latest NIHSS had improved to 4, and mRS to 2. Functionally, he had resumed independent self-care and basic household activities using compensatory strategies but had not yet returned to work due to persistent expressive aphasia and right-sided weakness.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient and his legal guardian for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

Key findings

This case underscores the clinical dilemma of managing ICAO in young patients who present with mild or transient symptoms. Despite initial improvement with conservative therapy, the patient experienced delayed infarct progression and neurological decline, ultimately requiring mechanical thrombectomy nearly two weeks after the initial event. The meaningful improvement following delayed intervention highlights the importance of individualized treatment strategies. Despite persistent expressive aphasia and right-sided weakness, the patient achieved functional independence in self-care and continues to make progress in speech and motor function, supporting that thrombectomy may remain beneficial beyond conventional time thresholds in select cases (3,4).

Strengths and limitations

A major strength of this case is the detailed documentation of clinical progression, imaging, and therapeutic decisions in a young adult without conventional stroke risk factors. It also provides follow-up data demonstrating meaningful recovery post-thrombectomy. However, as a single case, the findings cannot be generalized. Angiographic findings suggestive of ICA dissection with thrombosis of a false lumen support dissection as the likely etiology. The possibility of arterial dissection was considered, supported by the patient’s demographics, lack of atherosclerotic risk factors, and angiographic appearance. Although subsequent MRI and MRA did not confirm dissection, these modalities’ vessel wall sequences are not definitive for excluding intracranial dissection. Therefore, the diagnosis remained presumptive. The patient’s elevated protein C may represent an acute-phase response, but was not further explored, representing a limitation of the evaluation in this case (5,6).

Comparison with similar research

Recent studies have recognized that ICAO in young adults is often due to non-atherosclerotic causes such as arterial dissection or hypercoagulable states, rather than traditional vascular risk factors (2,7,8). Xu et al. emphasized that chronic ICAO is not necessarily a contraindication to intervention, particularly when clinical deterioration or perfusion mismatch is evident (3). Karki et al. presented a case of bilateral ICAO in a young adult that similarly required deviation from standard algorithms (4). Milhaud et al. concluded that carotid artery occlusion due to dissection is a more severe disease than previously thought and warrants early aggressive evaluation (8). These reports, like ours, support flexible and individualized approaches in managing young stroke patients. This perspective is supported by findings from the DAWN and DEFUSE 3 trials, which extended the therapeutic window for thrombectomy based on clinical-imaging mismatch rather than rigid time thresholds (9). These landmark studies reinforce the need to prioritize individualized imaging and clinical trajectories over strict adherence to clock-based cutoffs.

The case by Beutler et al. supports our experience, describing a 26-year-old woman with right ICA dissection and MCA occlusion who underwent endovascular thrombectomy nearly 60 hours after symptom onset (9). Despite the extended time window, the patient experienced a substantial functional recovery, reinforcing the growing view that patient selection based on imaging and clinical progression may be more important than rigid time-based criteria (10).

This case adds to the limited literature on intracranial ICA dissections in young adults, which are less common but may pose a higher risk of infarction due to limited collateral pathways and challenges in early detection.

Explanations of findings

The patient’s clinical course likely reflects dynamic infarct evolution in the setting of persistent large vessel occlusion. Angiographic findings of a supraclinoid stenosis proximal to an ICA stump, together with prior CTA results, were highly suggestive of intracranial dissection with thrombosis of a false lumen. While initial neurological improvement supported conservative management, limited collateral flow may have contributed to delayed infarct extension (1). The subsequent MCA involvement, radiographic progression, and midline shift signaled the need for urgent intervention. The decision to proceed with thrombectomy was based on new deficits and imaging changes, aligning with emerging evidence that endovascular therapy may still offer benefit in patients with neurological worsening, even outside conventional time windows (3,4,9,10).

Implications and actions needed

This case highlights the need for careful post-discharge surveillance and clinical reassessment in young stroke patients with ICAO, even if initial symptoms improve. Physicians should maintain a low threshold for reimaging and reconsideration of intervention when neurologic or radiographic worsening occurs. Current guidelines, while helpful, may not fully capture the nuances of stroke in young adults. Future research should aim to define criteria for delayed thrombectomy in this population, potentially incorporating dynamic imaging and clinical scoring systems to guide patient-centered decision-making (3,8,10).

Conclusions

This case illustrates the complexities of managing ICAO in young adults, particularly when initial symptoms are mild and appear to resolve. Although the patient was appropriately managed conservatively at first, he subsequently experienced delayed neurological deterioration and infarct progression. The decision to pursue mechanical thrombectomy was based on clear clinical and radiographic worsening, and the patient experienced partial functional recovery following intervention. Although he regained independence in activities of daily living with adaptive strategies, he continues to have expressive aphasia and right-sided motor deficits. This outcome supports the notion that delayed thrombectomy can still offer benefit in selected patients beyond traditional time windows, especially when there is evidence of evolving infarction and declining neurological status, even when complete recovery may not be achieved. The case reinforces the importance of close follow-up and a low threshold for reassessment in young stroke patients with ICAO, even after apparent early improvement. It also highlights the need for individualized treatment strategies and flexible application of existing guidelines in this unique patient population. Data from this case suggest that relying solely on initial clinical presentation may underestimate the risk of progression in young patients with ICAO, and that ongoing clinical and imaging evaluation is essential to guide timely intervention.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-2025-136/rc

Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-2025-136/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-2025-136/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Declaration of Helsinki and its subsequent amendments. Written informed consent was obtained from the patient and his legal guardian for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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