Tratamento trombolítico do acidente vascular cerebral isquêmico agudo

The enormous initial success of treating coronary thrombosis with thrombolytic therapy made the thrombolytic treatment of ischaemic stroke the obvious next step. Although coronary thrombolysis has now been superseded by primary angioplasty, thrombolysis is the standard of care for stroke if it can be done within 4.5 hours of the known onset of a stroke. ¹

Quão comum é o acidente vascular cerebral isquêmico? (Epidemiologia)²³⁴

• As of 2022, stroke was the fourth biggest single cause of death in England and Wales.

• There are around 100,000 strokes every year in the UK, with around 1.3 million people living with the consequences of stroke.

• Stroke incidence fell by 30% between 1999 and 2011, probably due to better management of cardiovascular risk factors in primary care.

• Embora a incidência aumente com a idade, a idade média caiu de 1 a 2 anos entre 2007 e 2016, quando era de 68 anos para homens e 73 anos para mulheres. Na Escócia, as idades equivalentes são 71 e 76, respectivamente.

• Não há limite de idade para o uso da terapia trombolítica.

Diagnóstico de acidente vascular cerebral isquêmico (investigações)⁵⁶

É essencial realizar uma tomografia computadorizada (TC) ou ressonância magnética (RM) para diferenciar o tipo de AVC antes de iniciar o tratamento. O uso da RM como ferramenta de primeira linha tem o potencial de reduzir a trombólise de imitações de AVC, mas isso não deve ocorrer à custa de atrasos. O acesso a essas investigações, e a profissionais treinados para interpretá-las, deve estar imediatamente disponível 24 horas por dia.

Diagnóstico diferencial

The important differential diagnoses are acidente vascular cerebral hemorrágico, including intracranial haemorrhage and hemorragia subaracnoide, e ataque isquêmico transitório (AIT).

Management of ischaemic stroke ⁵⁷

The 2023 National Clinical Guidelines for Stroke is endorsed by the National Institute for Health and Care Excellence (NICE), Scottish Intercollegiate Guidelines Network (SIGN) and the Royal College of Physicians. NICE also have a separate guideline on stroke, updated in 2022.

Recommendations include the following:

• A trombólise com alteplase - também conhecida como ativador do plasminogênio tecidual (tPA) - deve ser a trombólise de escolha quando a trombólise estiver sendo considerada. Seu uso deve ser limitado às seguintes circunstâncias:

  • O acidente vascular cerebral hemorrágico foi excluído.

  • O paciente se apresenta dentro de quatro horas e meia após o evento.

  • It is administered within a well-organised stroke service.

• Acute stroke services must link with the ambulance service; as well as being able to provide emergency care, they must also have facilities to deal with swallowing assessment, hydration and nutrition, palliative care, secondary prevention and rehabilitation. They must also provide education for all staff who give acute stroke care, including those in the emergency department.

• Todo paciente tratado com alteplase deve iniciar um agente antiplaquetário dentro de 24 horas, a menos que haja contraindicação.

• Pacientes que são elegíveis para trombectomia mecânica também devem receber trombólise o mais rápido possível.

Em 2023, apenas 10,7% dos pacientes que sofrem um AVC são tratados com trombólise, e 3,1% são tratados com trombectomia. Isso representa uma ligeira melhoria em comparação com 10,4% e 2,5%, respectivamente, no ano anterior. Apenas 40% são admitidos em uma unidade de AVC dentro de quatro horas e apenas 76,5% passam pelo menos 90% de sua estadia hospitalar em uma unidade de AVC.

A new NICE guidance published in July 2024 authorised the use of a second thrombolytic agent, tenecteplase, on the same basis (for thrombolysis up to 4.5 hours after presentation, when intracranial haemorrhage has been excluded). The guidance says that the less expensive of the two agents should be used. ⁸

Contraindicações para o tratamento trombolítico⁹

As contraindicações absolutas incluem uma hemorragia intracraniana recente ou lesão vascular cerebral estrutural ou neoplasia, possível dissecção aórtica, sangramento ativo (excluindo menstruação), cirurgia intracraniana ou espinhal recente e hipertensão grave não controlada atual.

Relative contraindications include a history of severe and poorly controlled hypertension, prolonged cardiopulmonary resuscitation (over 10 minutes), major surgery in the last three weeks, dementia, pregnancy, non-compressible vascular punctures and an active peptic ulcer.

Complicações¹⁰

The most serious complication is intracranial haemorrhage - a 2023 systematic review gave the likelihood of this as 1.7 - 8.8%. Risk factors for intracranial haemorrhage include age, hypertension, atrial fibrillation and the use of antiplatelet or anticoagulant therapy; however, a haemorrhage can only be confirmed or excluded after appropriate imaging. The Stroke Association patient leaflet gives an intracranial haemorrhage rate of 4% within seven days of thrombolysis and advises that 2.5% of these will be fatal.

Prognóstico¹¹

A 2018 study followed over 2000 patients who had received thrombolysis between 2005 and 2015. They found that the number needed to treat to prevent one death was 12 at five years and 20 at 10 years. Thrombolysis reduced mortality by 37% at 10 years (slightly more for those who arrived at hospital within three hours of symptom onset) and on average, by 10 years, treated patients had lived one year longer than controls. At five years, thrombolysis was associated with higher independence scores with an odds ratio of 3.76.

Implications for primary care

Admissão rápida

Although the high technology of scanning and thrombolysis is delivered within a hospital system, there are still implications for primary care, the most obvious being that the speed of getting a patient to a thrombolysis unit is critical. A nationwide cohort study in Denmark found that symptom to thrombolysis time of over 90 minutes was associated with a higher risk of death or recurrent ischaemic stroke. ¹²

Even if the 4.5 hour cut-off for thrombolysis has passed, patients should still be admitted to hospital, as all should have a scan within 24 hours and the outcome for all is better in a stroke unit.

Gestão inicial de TIA suspeita e confirmada³⁷

• Ofereça aspirina (300 mg diários), a menos que haja contraindicação, para pessoas que tiveram um AIT suspeito, a ser iniciada imediatamente. Aqueles que já estão tomando aspirina em baixa dose devem continuar com esta e não tomar uma dose de 300 mg.

• Refer immediately people who have had a suspected TIA for specialist assessment and investigation, to be seen within 24 hours of onset of symptoms. If someone presents having had a suspected TIA more than seven days ago, they should be referred as soon as possible and definitely within another seven days.

• Não use sistemas de pontuação, como ABCD², para avaliar o risco de um AVC subsequente ou para informar a urgência do encaminhamento para pessoas que tiveram um AIT suspeito ou confirmado.

• Ofereça prevenção secundária, além de aspirina, assim que possível após a confirmação do diagnóstico de AIT.

• Patients with a suspected TIA should not drive until they have seen a specialist, who will give definitive advice.

Prevenção secundária

This is discussed in the separate Prevenção de AVC artigo.