Can Interventional Cardiologists Help Deliver the UK Mechanical Thrombectomy Interventional Programme for Patients with Acute Ischaemic Stroke? A Discussion Paper from the British Cardiovascular Interventional Society Stroke Thrombectomy Focus Group.

There is a willingness among UK interventional cardiologists to contribute to provision of a 24/7 mechanical thrombectomy (MT) service for all suitable stroke patients if given the appropriate training. This highly effective intervention remains unavailable to the majority of patients who might benefit, partly because there is a limited number of trained specialists. As demonstrated in other countries, interdisciplinary working can be the solution and an opportunity to achieve this is outlined in this article.

Impact of COVID-19 on Stroke Caseload in a Major Hyperacute Stroke Unit.

Northwick Park Hospital in London, United Kingdom (UK) is one of the busiest stroke units in the country and is located in one of the areas most heavily affected by the COVID-19 pandemic in the first half of 2020. Admissions to the stroke unit and changes during the peak of COVID-19 were reviewed. Compared with the previous year, mean 96 patients were admitted with suspected stroke during April and May 2020 compared with mean 116 per month in non-COVID periods, ratio 0.82, P = 0.01. This reduction involved both strokes and mimics and was unlikely to have occurred by chance. Numbers of patients thrombolysed and of patients referred for thrombectomy decreased dramatically during this time. Mechanisms by which the COVID-19 pandemic and the March lockdown may have affected admissions to the unit are discussed. Reduced admissions to the stroke unit allowed it to contribute its resources to the care of patients with COVID-19 during the peak of admissions.

Decreasing referrals to transient ischaemic attack clinics during the COVID-19 outbreak: results from a multicentre cross-sectional survey.

OBJECTIVE: The COVID-19 pandemic is having major implications for stroke care with a documented significant fall in hospital acute stroke admissions. We investigated whether COVID-19 has resulted in a decreased number of referrals to the transient ischaemic attack (TIA) clinics across the North West London region. SETTING AND DESIGN: All the TIA clinical leads of the North West London region received an invitation by email to participate in an online survey in May 2020. The survey questionnaire aimed to assess the number of patients with suspected TIA consecutively referred to each of the TIA clinics of the North West London region between 1 March and 30 April 2020, the COVID-19 period, and between 1 March and 30 April 2019. RESULTS: We had a response rate of 100%. During the COVID-19 period, the TIA clinics of the North West London region received 440 referrals compared with 616 referrals received between 1 March and 30 April 2019 with a fall in the number of the referrals by 28.6%. In April 2020 compared with April 2019, the number of the referrals declined by 40.1%. CONCLUSIONS: This multicentre analysis documented a significant reduction in the number of patients referred with suspected TIA to the specialised rapid access outpatient clinics in the North West London region during the COVID-19 pandemic. Future studies are needed to confirm our findings and to better characterise the incidence of cerebrovascular disease during the COVID-19 pandemic.

Therapeutic hypothermia for acute ischaemic stroke. Results of a European multicentre, randomised, phase III clinical trial.

INTRODUCTION: We assessed whether modest systemic cooling started within 6 hours of symptom onset improves functional outcome at three months in awake patients with acute ischaemic stroke. PATIENTS AND METHODS: In this European randomised open-label clinical trial with blinded outcome assessment, adult patients with acute ischaemic stroke were randomised to cooling to a target body temperature of 34.0-35.0°C, started within 6 h after stroke onset and maintained for 12 or 24 h , versus standard treatment. The primary outcome was the score on the modified Rankin Scale at 91 days, as analysed with ordinal logistic regression. RESULTS: The trial was stopped after inclusion of 98 of the originally intended 1500 patients because of slow recruitment and cessation of funding. Forty-nine patients were randomised to hypothermia versus 49 to standard treatment. Four patients were lost to follow-up. Of patients randomised to hypothermia, 15 (31%) achieved the predefined cooling targets. The primary outcome did not differ between the groups (odds ratio for good outcome, 1.01; 95% confidence interval, 0.48-2.13; p = 0.97). The number of patients with one or more serious adverse events did not differ between groups (relative risk, 1.22; 95% confidence interval, 0.65-1.94; p = 0.52). DISCUSSION: In this trial, cooling to a target of 34.0-35.0°C and maintaining this for 12 or 24 h was not feasible in the majority of patients. The final sample was underpowered to detect clinically relevant differences in outcomes. CONCLUSION: Before new trials are launched, the feasibility of cooling needs to be improved.

Microcirculatory rarefaction in South Asians - a potential mechanism for increased cardiovascular risk and diabetes.

People of South Asian descent have an increased risk of cardiovascular disease (CVD) and diabetes, but little is known about the microcirculation in South Asian people despite evidence that this plays an important role in the aetiology of CVD. We compared the retinal microcirculation in a population-based sample of 287 middle-aged adults (144 European 143 South Asian) matched for age and sex. Retinal photographs were taken and analysed using a validated semi-automated program and microvascular measures were compared. Blood pressure, anthropometry and fasting bloods were also measured. South Asians had significantly fewer arteriolar and venular vessels and bifurcations. Arterioles and venules were longer and venules were also more tortuous in South Asians. These differences were not explained by adjustment for traditional risk factors including blood pressure, body mass index, diabetes or measures of insulin resistance. People of South Asian descent have rarefaction of the retinal microcirculation compared to age-sex matched individuals of European descent. Reduced microvascular density could contribute to the elevated risk of CVD and impaired glucose tolerance in South Asian people.

Renal impairment reduces the efficacy of thrombolytic therapy in acute ischemic stroke.

BACKGROUND: Renal impairment is a potent risk factor for stroke, which remains a leading cause of death and disability. Thrombolysis for acute ischemic stroke has transformed patient outcomes, although the safety and efficacy of this approach remain poorly characterized in patients with renal dysfunction, who manifest a higher risk of bleeding due to uremia. We therefore examined the impact of renal impairment on clinical outcomes with thrombolysis within the current 4.5-hour therapeutic window. METHODS: This retrospective multicenter cohort study (2009-2011) examined 229 stroke patients receiving thrombolysis with alteplase (0.9 mg/kg; mean age 70 ± 13 years; 59% male, 24% diabetic). Sixty-five patients had an estimated glomerular filtration rate (eGFR) <60 ml/min. The primary outcome was the improvement in National Institutes of Health Stroke Scale (NIHSS) score at 24 h. Secondary outcomes included the NIHSS score at 7 days, the incidence of symptomatic and asymptomatic intracranial hemorrhage (ICH), extracranial bleeding and death during the index hospitalization. Univariate and multivariate regression analyses were performed to determine the association between demographic characteristics and comorbid factors of interest and outcomes. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. RESULTS: There was no significant difference in mean time to thrombolysis between the groups (221 ± 66 vs. 220 ± 70 min from symptom onset; p = 0.9). An eGFR <60 ml/min was independently associated with a statistically significant reduction of the therapeutic effect of alteplase at 24 h on multivariate regression [coefficient -2.3, 95% confidence interval (CI) -3.7 to -0.9; p = 0.002], and this persisted at 7 days (coefficient -3.5, 95% CI -5.3 to -1.7; p < 0.001). On modeling eGFR as a continuous variable, every 10 ml/min decline in eGFR was associated with a 0.40 diminution in NIHSS score improvement with alteplase (95% CI 0.07-0.74; p = 0.02). Older age and a higher presenting NIHSS score were associated with a greater therapeutic effect (p = 0.04 and p < 0.001, respectively). In-patient mortality was 5%, with no significant differences between groups. Renal impairment was not associated with a higher rate of ICH (6.2 vs. 6.7%; p = 0.9). Greater NIHSS score at presentation was the only factor associated with a greater risk of death (odds ratio 1.24, 95% CI 1.10-1.40; p < 0.001) and ICH (odds ratio 1.12, 95% CI 1.03-1.23; p = 0.004). CONCLUSIONS: Our results suggest that renal impairment is associated with reduced efficacy of thrombolysis in acute ischemic stroke without any excess hemorrhagic complications. This may relate to diminished fibrinolysis in the uremic milieu or differences in infarct anatomy. Longer-term prospective studies are required to characterize and improve functional outcomes following stroke in a manifestly high-risk group.