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Beware of the DeBakey type I aortic dissection hidden by ischemic stroke: Two case reports

BACKGROUND DeBakey type I aortic dissection is one of the rare etiologies of ischemic stroke. It is critical to identify arterial dissection before intravenous thrombolysis; otherwise, fatal hemorrhage may occur. CASE SUMMARY In this report, we described 2 painless DeBakey type I aortic dissection cases with initial symptoms similar to ischemic stroke. Sudden onset of conscious disturbance and limb weakness within minutes occurred in both cases. Hypotension was found in both cases. Thoracoabdominal computed tomography angiography was urgently performed due to unknown reason hypotension, and DeBakey type I aortic dissection was confirmed. Intravenous thrombolysis was avoided because of timely diagnosis; however, they both eventually died of ruptured aortic dissection. CONCLUSION Aortic dissection should always be excluded in ischemic stroke patients with unexplained hypotension or shock symptoms before intravenous thrombolytic therapy.


INTRODUCTION
Acute ischemic stroke (AIS) is the leading cause of death and disability in the world. It is defined as the sudden loss of blood flow to an area of the brain, resulting in a corresponding loss of neurologic function. In order to rescue more penumbra tissue, vascular recanalization treatment, such as intravenous thrombolysis or endovascular clot retrieval, should be carried out as soon as possible because the recanalization time is directly related to the outcomes [1]. Although intravenous thrombolysis is widely used, carefully excluding patients with contraindications of thrombolytic therapy is critical. Aortic dissection is the absolute contraindication of thrombolytic therapy, and it is an uncommon, life-threatening cause of ischemic stroke. Typical aortic dissection presents with tearing chest or back pain, but painless aortic dissection with only focal neurological deficits can be a challenge for emergency physicians, and inadvertently treating this situation with thrombolytic agents may threaten the patient's life.
In this report, we describe 2 painless DeBakey type I aortic dissection patients presenting initial symptoms similar to ischemic stroke who were eligible for thrombolytic treatment. We report these cases with the aim to emphasize the importance of ruling out aortic dissection before fibrinolytic treatment in AIS patients. August 26, 2022 Volume 10 Issue 24

Case 2:
The patient died 10 h after admission when his family members were discussing whether to transfer him to a different hospital for surgical treatment.

DISCUSSION
Acute aortic dissection (AAD) is characterized by the rapid development of an intimal flap. This is caused by blood flowing into the media and forcing the intima and the adventitia apart, which leads to life-threatening complications and death, particularly when the ascending aorta is involved [2]. According to the location of the dissection and/or origin of the intimal tear and the extent of the dissection, AAD can be classified into Stanford type A (or DeBakey type I and type II) and Stanford type B (or DeBakey type IIIa and type IIIb). Stanford type A aortic dissections involve the ascending aorta and usually require swift, open surgical repair, whereas Stanford type B dissections involve the descending but not the ascending aorta and are conventionally treated by endovascular repair and/or medical therapy [2]. AAD is an uncommon but life-threatening disease with a reported incidence of 3-5 cases per 100000 people per year [3], a figure which may rise to even as high as 35 cases per 100000 people per year at the age of 65-75-years-old [4]. About 20% of the untreated patients with DeBakey type I aortic dissection died immediately, whilst a further 1%-2% of the survivors died with every hour of delayed treatment [5]. Stroke is one of the most serious complications of DeBakey type I AAD, and the incidence of DeBakey type I arterial dissection complicated with stroke is about 6% [6] to 10% [7]. Arterial dissection represents 5.7% of first-ever ischemic strokes of unusual cause in a clinical series [8]. Arterial dissection presented with stroke symptoms and without typical chest or back pain can lead to a delayed diagnosis of dissection and that can significantly increase the mortality. Furthermore, thrombolysis treatment can result in 3-5 fold higher probability of fatalities than non-thrombolysis treatment of patients [9]. Therefore, urgently identifying the presence of arterial dissection in stroke patients is critical.
While aortic dissection can involve both of the carotid arteries, right hemisphere involvement is more commonly seen in previous reports [7]. The frequency of chest/back pain is much lower in AAD patients combined with stroke than those without stroke [7]. Altered consciousness, which may be either due to the sudden drop of BP after arterial dissection or damage of the brain, can lead to delayed reporting of chest/back pain. SBP difference greater than 20 mmHg between the two upper limbs is one of the characteristics of AAD, but in our case series, none of them had such manifestations. Furthermore, pulse deficits are present in about 20%-30% of ADD cases which emphasizes the importance of serial physical examinations that can substantially contribute to the correct diagnosis. Transient or persistent low BP or shock symptoms should always be taken seriously in ischemic stroke patients because most ischemic stroke patients usually have higher BP [7]. D-dimer is an important predictive value in the diagnosis of AAD, and D-dimer values less than 0.5 μg/mL can be used to rule out AAD[10]. However, D-dimer elevation is also common in acute stroke, deep venous thrombosis and pulmonary embolism, particularly in cardioembolism [11]. D-dimer elevation has poor specificity in the diagnosis of aortic dissection, but is helpful to exclude aortic dissection when D-dimer is negative.
The contrast-enhanced CT scan is a reliable method for the definite diagnosis of AAD. In addition to enhanced CT scan, other auxiliary examinations, such as carotid ultrasound and chest X-ray, can also provide reference values for AAD diagnosis. Chest X-ray can be considered as part of the acute screening protocols in AIS patients with special enlarged mediastinal shadow in AAD. A common or internal carotid artery dissection can easily be investigated by ultrasonography, which can be regarded as a helpful, complementary tool for the current diagnostic workup [12].
Arterial dissection is a life-threatening emergency which needs urgent surgery or endovascular intervention. It is highly recommended to keep the SBP < 120 mmHg with intravenous β-blockers or vasodilators and careful management of any conditions that can increase thoraco-abdominal pressure is required to prevent the complication of aortic rupture prior to surgery or endovascular intervention.

CONCLUSION
In conclusion, when AIS patients developed a rapid peak of neurological symptoms, unexplained hypotension, or shock symptoms, arterial dissection as a differential diagnosis should always be excluded before intravenous thrombolysis. Serial monitoring, such as checking the differences in SBP between the two arms and peripheral arterial pulsation are important for diagnosis of arterial dissection. An abnormal carotid ultrasound finding and mediastinal widening on chest radiograph may also be helpful in identifying AAD. The elevation of D-dimer has no specificity value in diagnosing arterial dissection, but its negative value has high specificity in excluding AAD. For AIS patients who are suspected of arterial dissection, enhanced CTA examination is needed urgently to confirmed the diagnosis. To avoid arterial rupture, close monitoring of vital signs, ensuring proper bed rest, and the treatment of coughing and constipation are very important.

FOOTNOTES
Author contributions: Chen SQ and Luo WL contributed to manuscript writing and editing; Luo WL contributed to conceptualization and supervision; Liu W and Wang LZ contributed to data collection and data analysis; All authors have read and approved the final manuscript.
Informed consent statement: All study participants, or their legal guardian, provided informed written consent prior to study enrollment.

Conflict-of-interest statement:
All the authors report no relevant conflicts of interest for this article.