Acute stroke in a patient already anticoagulated

No - intravenous thrombolysis is contraindicated.

• Current treatment with a vitamin K antagonist with an INR greater than 1.7 is an absolute contraindication to intravenous alteplase (or tenecteplase). His INR is 2.6.
• The reason is the unacceptable risk of symptomatic intracranial haemorrhage when systemic coagulation is already impaired; there is no evidence that correcting the INR with prothrombin complex concentrate makes thrombolysis safe.
• He is otherwise a strong thrombolysis candidate: within the window, no haemorrhage on CT, glucose normal, no early ischaemic change, independent before the event - which is exactly why the anticoagulation status must be checked before the team defaults to thrombolysis.

Important corollary: the fact that thrombolysis is contraindicated does not mean he receives no reperfusion therapy. It redirects the pathway to mechanical thrombectomy, which is the next question.

Urgent CT angiography (with CT perfusion if there is any uncertainty about the time window or the extent of salvageable tissue) to look for a large vessel occlusion.

• If a proximal occlusion (e.g. M1 or internal carotid artery) is found, he should be transferred immediately for mechanical thrombectomy.
• Anticoagulation with warfarin is not a contraindication to mechanical thrombectomy. The procedure can be performed safely on therapeutic anticoagulation, and this is the key judgement point - clinicians sometimes wrongly exclude these patients from all reperfusion therapy.
• Thrombectomy may be offered in an extended time window (up to 24 hours in selected patients) when perfusion imaging shows salvageable tissue.

Blood pressure management:

• For patients undergoing mechanical thrombectomy, the target is below 185/110 mmHg before the procedure. His BP of 198/104 mmHg needs cautious lowering with intravenous labetalol or a similar agent, avoiding precipitous falls.
• Do not lower blood pressure aggressively outside these thresholds: if thrombectomy is not possible, permissive hypertension is generally preferred in acute ischaemic stroke.
• Do not routinely reverse the warfarin before thrombectomy - reversal is reserved for bleeding or for a planned intervention where haemostasis is critical, discussed with the stroke team.

After the procedure, anticoagulation should be reviewed and the timing of restarting it individualised; he needs investigation for the cause of his AF-related stroke and a long-term plan.

If no LVO:

• He continues on therapeutic warfarin. Because he was already adequately anticoagulated at the time of the stroke (INR 2.6, within the target range for AF), this is a treatment failure rather than a failure of adherence.
• Admit to the stroke unit, with swallow assessment, hydration, early mobilisation, and treatment of fever and hyperglycaemia.
• Aspirin is not added to therapeutic warfarin for secondary prevention because of bleeding risk; dual therapy is not appropriate here.
• Consider whether the underlying cause is cardioembolic (AF), but also look for other mechanisms - carotid imaging, echocardiography, and review of whether anticoagulation control has been consistently good.

Secondary prevention:

• Optimise anticoagulation - check time-in-therapeutic-range; if control has been poor despite adherence, consider switching to a DOAC (with attention to renal function and valve status; DOACs are contraindicated in mechanical valves and moderate-to-severe mitral stenosis).
• Address vascular risk factors: blood pressure, lipids, diabetes, smoking, alcohol, weight.
• Assess for patent foramen ovale only if there is a plausible embolic source and the AF explanation is in doubt.
• Reassess driving, occupation and home circumstances before discharge, and involve the multidisciplinary team.