Thrombolysis in the elderly
After age of 55 years, the risk of having AIS doubles for every additional 10 years of life.58 59 AIS-related in-hospital mortality was 1–2 times higher in those ages older than 80 or 90 years according to the report from the Get with the Guidelines.60 61 The risk of sICH also increased after intravenous tPA in AIS patients older than 80 years old.39 62 63 However, a meta-analysis still revealed that intravenous tPA reduced 3-month mortality in patients >80 years.62 The rate of sICH in older patients with AIS may vary by different criteria. When using the ECASS criteria, multiple observational studies found no increased risk of sICH in elderly patients post intravenous tPA.64 65 However, the rate of sICH doubled in patients older than 80 years post intravenous tPA in NINDS trial.62 A recent meta-analysis showed no significant difference post intravenous tPA comparing AIS patients ≥80 years with those <80 years.63 Moreover, patients older than 80 in the ENCHANTED trial were safe in their subgroup analysis.66
Recommendation
Older patients may have an overall poor prognosis post stroke with increased risk of mortality and haemorrhage comparing with younger patients. However, older age does not change the potential benefit of thrombolytic treatment. In AIS patients who are >80 years and with onset time of <3 hours, intravenous tPA is recommended (Class I, Level of Evidence A). The benefit of full-dose intravenous tPA for AIS patients >80 years and within 3–4.5 hour of onset is unclear (Class IIb, Level of Evidence B).
The issue of stroke severity and stroke subtypes
Mild or severe stroke was removed from the list of exclusion criteria67 in the 2013 AHA/ASA guidelines on the management of AIS. For those strokes that take place within 3–4.5 hours of onset, patients with severe stroke were still excluded.67However, the ENCHANTED trial has shown that it was safe for both mild and severe stroke patients in its subgroup analysis.66
Severe strokes
For severe stroke symptoms, intravenous alteplase is indicated within 3 hours from symptom onset. However, it was one of the contraindications for the 3–4.5 hour time window in ECASS 3.11 The severity of stroke at baseline is the strongest predictor of future functional independence or mortality in patients after their first AIS.58 63 Subgroup analysis of NINDS studies found that patients with severe strokes could still benefit from IV with a favourable outcome comparing with those not treated.68 Patients with severe strokes had a higher rate of haemorrhagic transformation and in these patients, haemorrhage might not be related to the use of intravenous tPA.29 The evidence is insufficient to not offer intravenous tPA to patients with severe strokes or early signs of infarction. Patients with severe stroke and early ischaemic changes on CT was not a contraindication for intravenous tPA.16 69 70
Mild stroke
NINDS studies did not list the lower limit of the71 72NIHSS score for using intravenous tPA.5 Several meta-analysis have found that patients with mild stroke were still significantly disabled at 3 months71–76. Such disability could be from motor deficits, cognitive impairment, fatigue or depression, which could not be assessed by NIHSS.71 77 78 Since then, the ENCHANTED trial has also included patients with mild strokes between 3 and 4.5 hours of onset.66 Although the trial did not reach its predetermined non-inferiority hypothesis, intravenous tPA 0.6 mg/kg showed some efficacy but less haemorrhage in this subgroup.66 Rapid improvement and mild stroke were two main reasons of why thrombolysis was not given.79 The treatment should not be delayed due to the improvement of symptoms, while the treatment time window missed. Thrombolytic therapy should be given as early as possible.
Recommendation
For AIS patients with severe stroke symptoms, intravenous tPA is recommended within 3 hours of symptom onset. Although risk of haemorrhagic transformation may increase, there is still proven clinical benefit (Class I, Level of Evidence A). For patients with mild but disabling stroke, intravenous tPA is indicated within 3 hours of onset (Class I, Level of Evidence A).
For patients with mild but non-disabling stroke within 3 hours of onset, intravenous tPA might be administrated (Class IIb, Level of Evidence C). For AIS patients with moderate or severe stroke however clinically improving but still have neurological deficit, intravenous tPA is recommended (Class IIa, Level of Evidence A).
Onset to treatment time is a main factor predicting the outcome; therefore, continuing to observe patient and delay the treatment with intravenous tPA is not recommended (Class III, Level of Evidence C).
Intravenous tPA treatment is indicated in patients with early ischaemic changes on CT stroke and within the tPA time treatment window (Class I, Level of Evidence A).
Intravenous tPA is reasonable for patients with moderate to severe ischaemic stroke and early improvement but remain moderately impaired and potentially disabled (Class IIb, Level of Evidence C).
Intravenous tPA is not recommended to patients with extensive hypodense lesion on CT scan. Extensive hypodense lesions may predict that the damage of brain is irreversible (Class III, Level of Evidence A).
For patients with mild but disabling stroke symptoms, intravenous tPA is indicated within 4.5 hours of symptom onset (Class IIb, Level of Evidence A). Treatment of patients with mild ischaemic stroke symptoms that are judged as non-disabling may be considered, but the benefit is unclear.
Subtypes of stroke
The subgroup analysis of NINDS studies in 1995 has found that all subtypes of patients with AIS would benefit from intravenous tPA.80 A multicentre registry study has found that a small number of patients with large vessel stenosis would have a better 7-day prognosis with thrombolysis.81 However, all subtypes improved with no statistical significance by 90 days81. One study found that early intravenous tPA would benefit AIS patients with cardiogenic middle cerebral artery occlusion.82 Another large study did not find any significant difference in treating patients with cardiogenic or non-cardiogenic type of stroke.83 One Chinese prospective single-centre study suggested that mild cardiogenic stroke was a predictor of mortality84; another study revealed that patients with cardioembolic stroke had an increase risk of haemorrhage after thrombolysis but without statistical significance among all subgroups of patients with sICH.85
About a quarter of stroke was of lacunar type and usually had favourable outcome,80 which was supported by two large national registry studies.81 86 Lacunar stroke was also an independent prognostic factor for favourable outcome.85 87 However, some still had concerns of the risk with thrombolysis in patients with small vessel disease or previous history of small cerebral vasculopathy.70 88
Recommendation
Intravenous tPA is indicated for patients with AIS of all subtypes. There is no need to delay the treatment in order to rule out a possible cardiac source of emboli, such as in patients with atrial fibrillation (Class II, Level of Evidence A).
The benefit of intravenous tPA is unclear in AIS patients with small cerebral vasculopathy (Class III, Level of Evidence C).
Intravenous tPA in patients with previous use of antithrombotic agents
Patients who had a stroke are often on antithrombotic agents, oral anticoagulants, heparin or low molecular weight heparin (LMWH) and/or recent treated with of tPA. A small retrospective study explored the safety of thrombolysis in patients on antiplatelet agents and found that the risk of sICH was not increased, but parenchymal ICH rate rose substantially.89 One retrospective study in China found potential risk of sICH in patients on antiplatelet therapy.90 One large randomised controlled study reported that patients on antiplatelet agents had a trend of developing haemorrhage but without statistical significance,7 which was supported by meta-analysis findings.91
According to the previously published guidelines and drug information, INR >1.7 or PT >15 s in AIS patients with onset of <3 hours were two contraindications for intravenous tPA.1 67 In addition, regardless of the value of INR, it would be contraindicated if a patient was on anticoagulant.11 One large registry study demonstrated that warfarin increased the risk of sICH.92 However, after adjustment for stroke severity, age and comorbidities, the risk of sICH was not increased if INR was in the therapeutic range.46 Compared with unfractionated heparin, LMWH does not prolong PTT but has more biological activity and longer duration of action. Therefore, patients on LMWH within 24 hours of onset of stroke are not suitable for intravenous thrombolytic therapy due to increased risk of haemorrhage.
Direct thrombin inhibitors (dabigatran and argatroban) have become the first-line treatment for stroke prevention in patients with non-valvular atrial fibrillation or peripheral vascular disease. A prospective study of 65 patients who received combination of intravenous argatroban and tPA found that the rate of recanalisation rate was 61% and rate of haemorrhage was 4.6%.93 Idarizumab, as the antidote of dabigatran, can block the action of dabigatran in several minutes. After careful consideration and reversal of dabigatran with idarizumab, intravenous tPA could be given.94 PT and aPTT could be prolonged in patients on oral FXa inhibitors (apixaban and rivaroxaban). Even with normal aPTT, INR, platelet count, ecarin clotting time, thrombin time, or direct factor Xa activity assays, or no history of receiving these non-vitamin K oral anticoagulants in the past 48 hours (assuming renal function is normal), the efficacy and safety of intravenous tPA remains unclear.
Recommendation
Intravenous tPA is indicated in patients who are on aspirin, clopidogrel, dual antiplatelet therapy or warfarin with an INR ≤1.7 (Class IIb, Level of Evidence B).
Intravenous tPA is contraindicated in patients on warfarin with an INR >1.7 (Class III, Level of Evidence B).
Intravenous tPA is contraindicated in patients on LMWH within the previous 24 hours, no matter LMWH is used for prevention or treatment of thrombosis (Class III, Level of Evidence B). If the patient has not received a dose of these for >48 hours, intravenous tPA should be considered.
The evidence of giving intravenous tPA in patients on either direct thrombin inhibitors or direct factor Xa inhibitors has not been firmly established but could be harmful (Class III, Level of Evidence C).
The use of intravenous tPA in patients on direct thrombin inhibitors or direct factor Xa inhibitors is not recommended (Class III, Level of Evidence C).
Platelet count
Although platelet count of <100 000 mm3 was a contraindication for thrombolysis, clinically patients with thrombocytopaenia were rare and a large pooled analysis reported that it was present in only small number of cases.95 Another two observational studies confirmed this finding and reported that the rate of sICH was low.96 97
In the past, test of clotting function was essential before thrombolysis. Clinical research found that INR was rarely elevated in patients not on any anticoagulants, or in hepatic failure, sepsis or other non-drug-related coagulopathy condition. One large registry study reported that 7 out of 152 patients with INR >1.7 or PT >15 s had sICH.96 After adjustment for age and baseline NIHSS, the prognosis of patients with INR >1.7 was not worse than others. Therefore, the safety or efficacy of intravenous tPA in patients with INR >1.7, aPTT >40 s, or PT >15 s cannot be confirmed currently. Since the chance of discovering thrombocytopaenia is rare in patients with AIS, unless there is a history of coagulopathy, it is unnecessary to check for coagulation studies prior to starting thrombolysis.
Recommendation
Intravenous tPA is not recommended in AIS patients with platelet count of <100 000/mm3, INR >1.7, aPTT >40 s or PT >15 s (Class III, Level of Evidence C).
Given the low risk of having thrombocytopaenia or coagulopathy in general population, there is no need to wait for the results of coagulation studies before considering intravenous tPA unless patient has history of coagulopathy (Class IIa, Level of Evidence B).
Intravenous tPA may be considered in patients with ESRD and on haemodialysis and other potential bleeding disorder if their coagulation studies are normal (Class IIb, Level of Evidence C).
Other stroke mimic conditions.
Issue of abnormal glucose level
Hypoglycaemia and hyperglycaemia are known to produce acute focal neurological deficits. China National Stroke Registry has found that <1% had a stroke mimic condition. In AIS patients with blood glucose levels of <50 mg/dL or >400 mg/dL, neurological examination should be repeated once abnormal glucose levels are corrected. If stroke symptoms still exist, intravenous tPA should be considered.
Recommendation
Intravenous tPA is recommended in otherwise eligible patients with an initial glucose levels of >50 mg/dL (Class I, Level of Evidence A).
If baseline blood glucose level is >400 mg/dL in patients with AIS, hyperglycaemia should be corrected first and then if neurological deficits are still present, intravenous tPA should be considered (Class IIb, Level of Evidence C).
Seizure at stroke onset
In the literature, over 300 patients with seizures at onset of stroke were treated with intravenous tPA.13 53 54 74 98 Among them, two had sICH. One of these patients had a remote history of surgical removal of a brain tumour. Therefore, seizure at onset of stroke is not an absolute contraindication for intravenous tPA.
Recommendation
Intravenous tPA is reasonable in patients with a seizure at the onset of acute stroke, and the limb impairment is ‘thought’ to be from stroke and not from Todd’s paralysis (Class IIa, Level of Evidence C).
Hypertension crisis
Patients with hypertension crisis may mimic stroke or top of the basilar artery occlusive syndrome. Uncontrolled or severe hypertension (systolic blood pressure >185 mm Hg or diastolic blood pressure >110 mm Hg on two or more consecutive measurements) is a known risk factor for postintravenous tPA sICH.44 Therefore, intravenous tPA is contraindicated unless the very elevated blood pressure is emergently controlled.99Two national stroke registries have found that the higher the blood pressure post intravenous tPA, the higher the risk of developing sICH.45 81 In the ENCHANTED trial, patients were randomised to the group with tight blood pressure control or standard blood pressure control.66 The trial found that patient had no better outcome if blood pressure was low. Presently, there is no strong evidence to support strict control of blood pressure prior to intravenous tPA aside from the recommended treatment range of <185/110 on administration and <180/105 thereafter.100
Recommendation
Intravenous tPA is indicated after treatment of hypertension to the goal of <185/110 mm Hg. Clinicians should stabilise blood pressure before starting intravenous tPA (Class I, Level of Evidence B).
Clinicians should lower blood pressure to the goal of <180/105 mm Hg after intravenous tPA has been given and maintained blood pressure at this level for at least 24 hours (Class I , Level of Evidence B).
Conditions that may potentiate haemorrhage disease
Tendency to develop haemorrhage in potentiate haemorrhagic diseases
Conditions that may potentiate haemorrhage include liver cirrhosis, end stage renal disease, haematological malignancy, vitamin K deficiency, sepsis, antiphospholipid antibody syndrome or potential bleeding disorder. The safety and efficacy of intravenous tPA in these patients are unclear.
Intravenous tPA in pregnancy and peripartum period
Currently, there is no evidence on whether pregnant woman can have intravenous tPA. It may be considered if not teratogenic. Only one review identified 12 reported cases of pregnant women with AIS received either intravenous tPA or endovascular therapy.95
Recommendation
In patients with history of potential haemorrhage diathesis or coagulopathy, the efficacy and safety of IV tPA are unknown. In these patients, intravenous tPA should be considered on an individual basis (Class IIb, Level of Evidence C).
Recent history of trauma, surgery or biopsy
A few studies considered that major surgeries should be the absolute contraindications for intravenous tPA. Clinicians must thoroughly balance the benefit of intravenous tPA and risk of haemorrhage with recent surgery. If the haemorrhage of a surgical site is compressible, thrombolysis can be given in selected patients. There is currently limited data on the use of intravenous tPA in patients with trauma. One report of 121 patients with dissections and treated with intravenous tPA showed no safety concerns when stroke their AIS was from the dissection of the cervical vessels related to trauma.101
Major intracranial/spinal surgeries might increase the risk of haemorrhage at the site of operation after intravenous tPA and therefore negate any benefit of thrombolysis. Previously, intravenous tPA was contraindicated in patients with AIS who had non-compressible arterial puncture site within 7 days of onset of stroke.67 With the advent of bridging therapy, patients now are receiving both intravenous and IA therapy despite the puncture of the femoral artery after intravenous tPA.102–109 Therefore, groin puncture itself is not a contraindication for intravenous tPA anymore.
Recommendation
For patients with major head trauma or a history of intracranial/spinal surgery within the prior 3 months, intravenous tPA is potentially contraindicated (Class III, Level of Evidence C).
The safety and efficacy of administering intravenous tPA to patients with AIS who have had an arterial puncture of a non-compressible site within 7 days is uncertain (Class IIb, Level of Evidence C).
Intravenous tPA therapy should be avoided in patients who have had lumbar puncture within last 7 days, although it can still be considered (Class IIb, Level of Evidence C).
Previous intracranial abnormalities
Limited data are available in patients with history of stroke within 3 months and treated with intravenous tPA. Case series reports suggested that patients with a history of unruptured intracranial aneurysms were safe when treated with intravenous tPA and without significantly increased risk of haemorrhagic transformation.110–115 Even these reports could be biased, evidence indicated that intravenous tPA in these patients was relatively safe. Safety of intravenous tPA in patients with intracranial vascular malformations (cavernous haemangioma, telangiectasia, developmental venous abnormality, arteriovenous malformations and arteriovenous fistula) is unclear.116–118
Recommendations
Use of intravenous tPA in patients presenting with AIS and a prior history of ischaemic stroke <3 months may be harmful (Class IIb, Level of Evidence B).
For AIS patients with a small or moderate sized (<10 mm) unruptured intracranial aneurysm, intravenous tPA is reasonable (Class IIb, Level of Evidence C).
In AIS patients with a giant unruptured intracranial aneurysm, the balance of benefit and risk is unclear (Class IIb, Level of Evidence C).
Haemorrhagic retinopathy or other haemorrhagic ophthalmological conditions
The condition of having an ischaemic stroke and intraocular haemorrhage is rare. In patients without diabetes, the rate of developing retinal haemorrhage after intravenous tPA was around 0.003%.119 Such haemorrhage is also rare in patients with diabetes . Therefore, intravenous tPA is not contraindicated in patients with diabetic retinopathy.
Recommendation
Intravenous tPA is indicated in patients with diabetes with haemorrhagic retinopathy or other history of intraocular haemorrhage. However, the risk of developing blindness from haemorrhage is real. The balance of benefit and risk of intravenous tPA should be discussed before treatment (Class IIa, Level of Evidence B).
Concomitant heart disease
AIS patient with concomitant myocardial infarction (MI) should receive intravenous tPA at 0.9 mg/kg first and proceed to percutaneous transluminal coronary angioplasty and stenting therapy (PTCAS). In these patients, pretreatment with intravenous tPA does not decrease the benefit of coronary PTCAS. There is limited data on the benefit of intravenous tPA in patients with recent MI (3 months). The benefit may vary depending on the type of MI the patient has (ST segment elevated MI, STEMI vs non-STEMI) and the location of MI.
Recommendation
For AIS patients with history within the past 3 months, also presenting with concurrent non-STEMI (Class IIa, Level of Evidence C), right cardiac wall or inferior wall MI (Class IIa, Level of evidence C) and recent STEMI of left anterior wall MI (Class IIa, Level of Evidence C), intravenous tPA is indicated.