Abstracts & Commentary
Sources: Lewis MJ, et al. Economy class stroke syndromes: Vertebral artery dissection revisited. J Neurol Neurosurg Psychiatry. 2003;74:1594-1595; Touzé E, et al. Risk of stroke and recurrent dissection after a cervical artery dissection: A multicenter study. Neurology. 2003;61:1347-1351.
Economy class syndrome (ECS) refers to venous thromboembolic episodes among airline passengers who have remained immobile for long periods in cramped seating that impairs their circulation. Economy class passengers with little leg space are more likely to suffer such events than passengers in roomy first-class seats. The syndrome was first described by Bryan Jennett, professor emeritus of neurosurgery at Glasgow University, who suffered a pulmonary embolism after a lengthy flight.1
ECS also has been associated with ischemic stroke in young adults with patent foramen ovale, presumably as a result of paradoxical embolism.2
Lewis and associates reported a case of ECS caused by vertebral artery (VA) dissection associated with abnormal neck posture during a 7-hour flight. A 56-year-old man in economy class fell asleep with his head uncomfortably twisted to the right. Upon awakening, he experienced transient (15 minutes) and then persistent weakness and loss of pain and temperature sensation of his right arm and leg but not of his face or tongue. Brain MRI confirmed an acute left medial medullary infarct. Contrast-enhanced MR angiography demonstrated dissection of the left VA at the level of the second cervical vertebra and along its length to its junction with the basilar artery. Following treatment with antiplatelet agents and rehabilitation, the patient made a full clinical recovery.
In this case, trivial trauma, perhaps coupled with a disorder of the arterial wall, led to VA dissection and stroke. An important question to be answered is whether the patient is subject to a recurrence of dissection in the previously dissected and healed VA or in another cervical artery not previously involved. The recurrence of dissection in a healed artery is considered uncommon but can occur in another artery previously not dissected. A previous study3 found the recurrence of dissection at 10 years to be about 12% for all age groups, while the recurrence rate for patients younger than 45 was 17%. Cervical artery dissection occurs less frequently in the elderly, perhaps because atherosclerotic vessels are less susceptible to dissections.
Touzé and associates studied a historical cohort of more than 450 patients (mean age, 44 years) with cervical artery dissection followed for a mean of 31 months. Carotid artery dissections (384) were twice as common as VA dissections (170). Seventy-two patients (16%) had multiple dissections. The initial presentation was an ischemic stroke in 64%, transient ischemic attack in 12%, and subarachnoid hemorrhage in 1%. One quarter of patients had only local signs (ipsilateral headache, neck pain, Horner syndrome, pulsatile tinnitus, etc). The recurrence rate for stroke (0.3% per year) was very low. The incidence of cervical artery dissection recurrences was difficult to assess because some recurrent dissections are asymptomatic. Only the presence of multiple dissections at the initial presentation was significantly associated with an increased risk of ischemic event (hazard ratio, 4.2).
The term "economy class syndrome" has acquired general currency because it reflects the experience and anxieties of air travelers. The possibility of lower-extremity deep-vein thrombosis (DVT) during a lengthy airline flight (although the malady also can affect passengers on long train, bus, or car trips) emphasizes the need for passengers to take preventive measures such as moving about the cabin, doing in-seat exercises, etc.
Because of the primary association of ECS with venous thromboembolism, I do not believe that cervical artery dissection should be considered part of the syndrome. Dissections of cervical arteries tend to occur spontaneously in patients with underlying arterial disease and, unlike DVT, are not significantly associated with cramped seating.
The very low risk of stroke and recurrent cervical artery dissection reported by Touzé et al is welcome.
I have resolved to travel business class on all future flights for health-related reasons. — John J. Caronna, Vice-Chairman, Department of Neurology, Cornell University Medical Center; Professor of Clinical Neurology, New York Hospital; Associate Editor, Neurology Alert.
1. Cruickshank JM, et al. Lancet. 1988;2:497-498.
2. Isayev Y, et al. Neurology. 2002;58:960-961.
3. Schievink WI, et al. N Engl J Med. 1994;330:393-397.