Mechanical thrombectomy (MT) is the standard of care for the treatment of acute ischemic stroke due to large vessel occlusion, but the capacity to deliver this treatment can be limited in less populous areas and island territories. Here, we describe the case of a man who developed right MCA syndrome while in Bermuda who was successfully diagnosed, transported over 800 miles to the East Coast of the USA, and treated with MT within 24 h. This case underscores the benefits of having organized systems of care and demonstrates the feasibility of urgent transoceanic patient transportation for stroke requiring MT.

© 2022 S. Karger AG, Basel

Background

Mechanical thrombectomy (MT) has become the standard of care for the treatment of acute ischemic stroke due to large vessel occlusion (LVO). The capacity to deliver this treatment is limited to centers that have the equipment and expertise to perform MT which in the USA is limited to Comprehensive Stroke Centers, Thrombectomy Stroke Centers, and some Primary Stroke Centers with capacity for MT.

Numerous island territories in the Caribbean and elsewhere lack capacity for MT, though there is a significant need. Bermuda is a British Overseas Territory of 64,000 population located in the North Atlantic Ocean; northeast of the Caribbean region. The Caribbean region is bound to the north by the US mainland, to the west by the Gulf of Mexico, and to the south by the South American mainland. The Caribbean has a total population of over 42.5 million people with a further 60 million visitors per annum through air and cruise travel combined [1, 2]. Stroke is a major cause of death and disability in this population, with age-standardized Caribbean stroke mortality rates per 100,000 population, ranging from 46 in the Bahamas to 176 in Haiti in 2002 [3]. In 2017, ischemic stroke mortality accounted for 26–45% of all cardiovascular deaths across the Caribbean regions [4]. Socio-economic risk factors are unequally distributed across the Caribbean region, influencing stroke prevalence and outcomes. Age-standardized prevalence rates in 2017 for acute ischemic stroke in low-income countries (e.g., Haiti) was 75 per 100,000, while prevalence rates within upper-middle-income countries such as Cuba, Dominican Republic, and Jamaica ranged from 116.1 to 143.5 per 100,000. This contrasts with high-income Caribbean countries (e.g., Antigua, Barbados, and Trinidad and Tobago) and Bermuda, with stroke prevalence rates of 67.5–82.8 [4]. Increased access to acute stroke care including MT, particularly in low-income countries, could have a dramatic impact on reducing stroke morbidity and mortality.

We organized a Primary Stroke Center at Bermuda’s King Edward VII Memorial Hospital (KEMH) that launched in 2019. This organization, a collaboration between Johns Hopkins Medicine International and Bermuda Hospitals Board, initially entailed the establishment of protocols for screening, rapid evaluation, and treatment of ischemic stroke patients with IV thrombolysis. KEMH, a 169-bed community hospital established in 1920, does not have capacity for MT.

In June of 2020, we started a Telephone Consultation with Imaging Review and Standardization (TCIS) program, to provide acute stroke care remotely by the neurology team at KEMH. In December of 2020, we transitioned to an off-island Johns Hopkins Stroke Team. As part of the collaboration, and for the purpose of TCIS, stroke neurologists from JHH were given practicing privileges at BHB and registered with the Bermuda Medical Council. As we started this service, our aim was to provide expert advice regarding acute stroke treatment, primarily with thrombolytic therapy and early management of ischemic and hemorrhagic stroke. Given that neurosurgical services are not available at KEMH, we included a process for rapid transfer of patients to the Comprehensive Stroke Center at the Johns Hopkins Hospital. JHH was already within the referral network for many health insurance companies in Bermuda. In regards to MT, whether we could transfer patients fast enough was unknown. Transfer of critical patients out of the island requires a fixed wing air ambulance. Since no teams or air ambulances are stationed in Bermuda, a team needs to be activated from a base in the East Coast of the USA. Several companies provide this service with bases in various states, for example, Florida and South Carolina. The process involves many additional logistical challenges, including immigration processing, insurance clearance, and contracting of the service provider.

We believe this case represents proof of concept that a transoceanic transfer can be done for MT, at the same time revealing the challenges associated with it. We pre­sent the case and discuss lessons learned and next steps.

Case

A 70-year-old man from Bermuda presented to KEMH with left-sided hemiplegia, left neglect, and right gaze deviation. His medical history was notable for atrial fibrillation on apixaban for stroke prophylaxis, hypertrophic cardiomyopathy status post-automatic implantable cardioverter-defibrillator, and prior ischemic strokes. At baseline, he had mild residual ataxia from a prior cerebellar stroke but was independent in all activities of daily living with a baseline modified Rankin score (mRS) of 1. In the current episode, the onset of symptoms was observed by his wife at 7:00 p.m. EST, and he was brought directly to the hospital. The initial NIH stroke scale (NIHSS) was 16. CT head was normal with the Alberta Stroke Program Early CT Score (ASPECTS) of 10. Head and neck CTA showed right M1 occlusion with good collateral blood flow. The patient was discussed with the Johns Hopkins TCIS consultant at 10:00 p.m. EST. IV thrombolysis was contraindicated due to current use of apixaban. MT was recommended but not available in Bermuda; therefore, the decision was made to transfer to Johns Hopkins Hospital (JHH) for possible MT. This decision was made at 10:00 p.m., 3 h after onset of symptoms.

He was transported via air ambulance. The air evacuation team consisted of an anesthetist and a nurse anesthetist with ventilator equipment available. Blood pressure parameters were to maintain systolic measures between 160 and 180 mm Hg. Normal saline infusion was maintained at 100 mL/h. NIHSS and vitals were assessed every 30 min in flight.

He arrived the next day at 2:30 p.m. EST, 17 h after symptom onset. His exam had improved to NIHSS 3 with mild left-sided face and arm weakness and dysarthria. Repeat CT head showed no areas to suggest completed infarct (ASPECTS 10; Fig. 1a). CTA showed distal right M1 occlusion. The CT perfusion scan was analyzed by RAPID software (RAPIDAI). There was no ischemic core defined by CBF <30%, but a 66-mL area of hypoperfusion defined by Tmax >6 s in the right middle cerebral artery (MCA) territory (Fig. 1b). The hypoperfusion intensity ratio (Tmax >10 s volume/Tmax >6 s volume) was 0.3. Given the significant area of hypoperfusion without the ischemic core, he was taken to the angiography suite for MT at 3:30 p.m. EST (18 h after symptom onset). Cerebral angiography showed proximal thrombus in the right MCA superior division (Fig. 1ci, iii). TICI3 recanalization was achieved after one pass with aspiration (Fig. 1cii, iv). NIHSS 24 h after MT was 3, and MRI brain obtained on day 2 showed acute infarcts in the R caudate and lentiform nucleus (Fig. 1d), R middle frontal gyrus, and L cerebellum.

Fig. 1.

Diagnostic CNS imaging after transoceanic transport in acute stroke. a CT scan of the head without contrast showed no evidence of early ischemic changes (ASPECTS 10). b CT perfusion scan showed no significant ischemic core as measured by in cerebral blood flow (CBF), but a large penumbra represented as increased Tmax in the right MCA territory. c (i) Cerebral angiography revealed an occlusion in the right MCA. (ii) After MT, blood flow was restored to the right MCA territory. Lateral images of cerebral angiography, (iii) pre-MT, and (iv) after 1st pass. d MRI scan 24 h after MT showed acute infarct in the right basal ganglia.

Given his history of recurrent cardioembolic strokes despite systemic anticoagulation, he underwent testing for causes of hypercoagulability that revealed APC resistance (1.5; normal value ≥2.1). Transthoracic echocardiogram showed severe left atrial dilation, and subsequent transesophageal echocardiogram (TEE) showed a dense “smoke-like” signal in the left atrial appendage possibly representing a thrombus. He was started on heparin infusion for anticoagulation and transitioned to enoxaparin 1 mg/kg BID at time of discharge with plan for repeat TEE in 6–8 weeks. At the time of discharge, he had improvement in left-sided weakness, specifically in grip strength and hand coordination, though NIHSS remained 3. His mRS at 90 days post-MT was 1. He eventually underwent left atrial appendage closure with a Watchman device.

Discussion

In this report, we describe a slowly progressing right MCA syndrome in a patient from Bermuda, who was successfully diagnosed, transported over 800 miles to the East Coast of the USA, and treated with MT within 24 h.

Transport/Systems of Care Considerations

This case underscores the benefits of having organized systems of care. It also is proof of concept that urgent transoceanic patient transportation for stroke requiring MT is possible, although the process needs to be streamlined.

The transfer and subsequent treatment were facilitated by a preset workflow allowing for rapid decision-making in acute stroke, including automatic transfer of images to a Web imaging portal/viewer, the call system, and medical record implementation (Fig. 2). Integral to this paradigm is a framework that allows for “real-time” review of images from the remote hospital and evaluation using a CTP analysis software to determine eligibility. The underlying infrastructure of the established TCIS program greatly impacted the ability to complete the transfer in the shortest time possible at the time. Transoceanic stroke care requires an additional layer of logistics including intergovernmental coordination, institutional agreements, and rapid mobilization of the air ambulance and critical care transport team.

Fig. 2.

Schematic of the Telephone Consultation with Imaging Review and Standardization (TCIS) program workflow. After arrival at King Edward Memorial Hospital (KEMH), patients with acute stroke are triaged, and imaging is obtained per ED protocol. The KEMH ED physician then calls the Johns Hopkins Hospital (JHH) hospital access line (HAL) and is connected to the JHH tele-stroke consultant. The tele-stroke consultant reviews the history and imaging, requesting additional imaging if needed, and then provides a treatment recommendation. If determined to be a candidate for transoceanic MT, the KEMH ED physician, JHH HAL, and JHH tele-stroke physician coordinate patient transport and alert appropriate treatment teams at JHH. IVT, IV thrombolysis.

Continued improvements in the process efficiency will enable transfers in faster time and potentially offer treatment to more patients. The medical decision to transfer is followed by a standardized financial clearance based on the level of insurance coverage. This patient required governmental assistance, and with the growing population of uninsured or underinsured, this pathway will continue to be relevant. We have initiated talks with insurance companies in Bermuda, who agreed to modify their procurement process for quicker contracting and activation of a service provider. Also, the process of the medical social worker in Bermuda has been streamlined as well. We continue to collect quality and outcome data from our stroke and TCIS program, to be able to improve on the process.

Treatment of a Low NIHSS Patient with LVO

The patient presented here had a slowly progressive LVO, defined by small ischemic core and large penumbra on delayed presentation. Even after optimization, transoceanic transport will inevitably take hours, and therefore, slowly progressive LVOs may be most amenable to this type of intervention. A recent study suggests that slow progressors constitute the majority of LVOs [5], with ischemic tissue thought to be temporally supported by collateral circulation [6, 7]. Importantly, at least a third of patients with low NIHSS and LVO suffer subsequent neurological deterioration [8], and slow progressors benefit from MT within the 6–24 h window from last known well [9]. We realize that treatment of patients with LVO and low NIHSS continues to be controversial and that there are several clinical trials currently evaluating this. However, treatment of these patients is standard in many centers, based on non-randomized data and meta-analysis.

As with much of modern medicine, access to care remains a critical limitation to successful treatment of acute stroke. Therapies such as TPA and MT can lead to vastly improved outcomes, but there is limited access to expertise and equipment to diagnose stroke and provide these interventions. The issue of limited access extends to numerous island countries and territories without large tertiary care centers. Patient transport to centers with MT capability remains the most feasible solution given currently available technology, but up-and-coming techniques like robotic remote endovascular therapy may ultimately help provide access [10]. All solutions, however, require planning and investment in organized systems of care. Despite the lack of access, there is a large need. Stroke is the second leading cause of death and third leading cause of death and disability in Bermuda [11]. This case demonstrates that treating patients with MT after transatlantic transport is possible. It also underscores the benefits of organizing stroke care including the building of infrastructure for fast detection, assessment, and treatment of stroke. This was conducted using methodology that we have implemented before in international collaborations [12]. Further investment in this organization, by working with insurance providers to expedite the approval process and logistics of a transoceanic emergency transfer and the use of CTP analysis software locally to better select patients based on factors such as the hyperintensity ratio, will need to be tested in a larger number of patients. A traditional randomized trial will be difficult in this scenario; however, studies of prospectively acquired data and outcomes may prove useful. Widespread implementation [13] of transoceanic stroke care has the potential to provide access to hundreds of thousands of people living in Bermuda and other island countries and territories.

Statement of Ethics

This report was prepared in accordance with the Johns Hopkins University Office of Human Subjects Research Institutional Review Board Policy No. 102.3 (JHM Organization Policy on Single Case Reports and Case Series). Ethical approval was not required for this study in accordance with local guidelines. Written informed consent was obtained from the patient for publication of this case report and any accompanying images.

Conflict of Interest Statement

The authors have no conflicts of interest to declare.

Funding Sources

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Author Contributions

Sachin P. Gadani, Francene Gayle, Phillip Jones, Phillipe Gailloud, Roland Faigle, and Victor C. Urrutia wrote and edited the main body of the text. Sachin P. Gadani, Francene Gayle, and Victor C. Urrutia wrote and edited the discussion section. Sachin P. Gadani generated the figures.

Data Availability Statement

All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.

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