Intravenous tPA in the treatment of acute stroke related to aortic dissection

Abstract

A 61-year-old woman with no prior medical illness presented with acute onset stroke symptoms. She had no chest pain at the time of presentation. However, CT angiogram showed an extensive aortic dissection, resulting in hypoperfusion of the right cerebral hemisphere and thus causing stroke symptoms. Due to this finding, tissue plasminogen activator was not given and a negative outcome was avoided.

Background

Aortic dissection (AD) is a life-threatening but treatable emergency. It usually presents with chest and back pain. However, 10%–55% of patients might not experience any significant pain.¹ Neurological symptoms occur in 17%–40% of patients.² This may present as transient ischaemic attack/stroke. Tissue plasminogen activator (tPA) is used to treat acute stroke in a subset of patients within 3–4.5 hours of symptom onset. Imaging guidelines necessitate only a non-contrast CT of the head to rule out haemorrhage prior to administration. However, severe complications are highly likely when it is given in patients with AD presenting with neurological symptoms. We present a case of a woman who presented with acute onset stroke symptoms in whom the diagnosis of AD was established successfully.

Case presentation

A 61-year-old woman, with no prior history of hypertension or any other significant medical illness, presented to the emergency department (ED) with complaints of facial droop and left-sided weakness. She was brought to the ED by family within 30 min of symptom onset. On initial presentation, she was afebrile with a pulse of 78/min, respiratory rate of 20/min, blood pressure was 180/95 mm Hg and 98% SpO2 on room air. She did not have any chest pain or any other symptoms. On examination, she did not have any speech deficits and was awake and alert. She was noted to have left homonymous hemianopia, left nasolabial fold flattening and 4/5 strength in left upper and lower extremities on Medical Research Council (MRC) scale.

Investigations

CT of the head and CT angiography (CTA) of the head+neck with perfusion scans were ordered as per our hospital stroke protocol. The preliminary report of the non-contrast CT of the head was called in to the ED by radiology and was reported as normal. On receiving the preliminary report, an order for tPA was placed after discussing the potential benefits and risks with the husband. Meanwhile, the CTA was completed and images were viewed by the radiologist and the on-call neurologist. CTA of the head was normal. CTA of the neck showed Stanford type A AD involving the aortic arch (figure 1) extending proximally to the origin of the right brachiocephalic artery. The common, internal and external carotids were patent bilaterally. Perfusion sequences showed prolonged mean transit time in the right hemisphere with relatively normal blood volume images (figure 2). CTA of the chest and abdomen showed that the dissection extended distally to the pararenal abdominal aorta with about 70%–80% compromise of the true lumen distally and about 20% compromise of the brachiocephalic origin.

Figure 1.

CT angiography showing the dissection in the aortic arch. The arrows indicate the true lumen (TL) and false lumen (FL) of the dissection.

Figure 2.

CT perfusion scans showing prolonged mean transit time (left) and normal blood volume (right).

Treatment

Given the presence of an AD, the tPA order was cancelled. When the patient returned from the CT suite, she was noted to be normotensive. She was then transferred to a different centre for cardiothoracic surgery.

Outcome and follow-up

We followed up with the patient and after nearly a 4-week stay in the hospital and rehab, she recovered very well and did not have any residual neurological deficits.

Discussion

ADs can present with neurological symptoms in 17%–40% of cases.² Stroke is the most common neurological symptom in AD.^2–5 Neurological symptoms can sometimes remit before presentation to the ED.³ With regard to management of acute stroke, current protocol dictates that haemorrhage must be ruled out by a non-contrast CT of the head. If the patient then meets other criteria and is within the 3-hour window⁶ or 4.5 hours for a certain subset,⁷ he/she can be given tPA. However, administration of tPA in AD has been shown to result in extension of dissection into the pericardium, leading to cardiac tamponade. A review of the literature revealed that two patients who presented with stroke symptoms due to AD died following tPA,^{2 8} while few others initially worsened so tPA was stopped and they underwent emergent surgery with good recovery.^{9 10} In another case, the patient received some tPA but then worsened with hypotension and reduced left radial pulse rate. He was found to have left common carotid dissection and left intracranial internal carotid artery (ICA) occlusion. tPA was stopped and surgery was offered but the patient declined and died.¹¹ tPA has been previously reported to have been used in stroke from ICA dissection.¹² However, it appears that the risks of using tPA in AD are much higher and have been consistently associated with adverse outcomes. A CT angiogram of the neck will certainly help to diagnose an AD as in our case. In addition, physical examination findings such as hypotension, diminished pulses and aortic regurgitation murmur might indicate the presence of an AD. However, the International Registry of Acute Aortic Dissection showed that pulse deficits might be present in less than 20% of patients with type A dissection.¹³ In addition, an aortic regurgitation murmur was only found in 44% of patients with type A dissection.¹³ A routine chest X-ray is abnormal in 60%–90% of cases but can be normal even in type A dissections.^{13 14} Carotid ultrasound would help only if the dissection extends to the carotids, which it did not in our patient. Therefore, a CT angiogram would likely be of more value. Acute AD is a life-threatening emergency which can present as stroke, as shown in this case. Missing the diagnosis or administration of tPA can be fatal in such cases.

Learning points.

• Intravenous tissue plasminogen activator (tPA) is given for certain patients with acute ischaemic stroke.

• Aortic dissection (AD) can present as a stroke without typical symptoms of pain.

• Use of tPA in AD can be fatal.

• Being aware of this aetiology and testing for it will prevent mortality.