Management of Cervical Arterial Dissection

Experimental determination of rupture pressure and stress of adventitia of human middle cerebral arteries

Background Intracranial arterial dissections might be attributed to the particular biomechanical properties of their specific layers. Also, knowledge of adventitia properties would be crucial in the context of intracranial balloon angioplasty. Aims The purpose of this work was to determine the rupture pressure of separated adventitia and compare it to intact cerebral arterial segments. Methods Brain specimens were harvested from 14 autopsy subjects (age range from 23 to 86 years). Pressure-inflation tests were conducted on proximal segments of middle cerebral arteries and separated adventitia layers from contralateral arteries to assess the rupture pressure values. Results The averaged rupture pressure of adventitia layers was 1.41 SD 0.25 atm (1072 SD 190 mmHg), whereas for intact arterial segments it was 2.32 SD 0.70 atm (1763 SD 532 mmHg) and diminished with age according to nonlinear regression trends. The difference beetween the aformentioned rupture pressures was positively correlated with rupture pressure of intact arterial segments ( R²= 0.88; p < 0.001). Conclusions The obtained experimental results indicate a leading role of adventitia in building arterial strength under supraphysiological pressure conditions. The greater the rupture pressure of complete cerebral arteries, the smaller the contribution of adventitia in overall wall resistance.

Cerebrovascular Dissections—A Review Part I: Spontaneous Dissections

Spontaneous cerebrovascular dissections are subintimal or subadventitial cervical carotid and vertebral artery wall injuries and are the cause of as many as 2% of all ischemic strokes. Spontaneous dissections are the leading cause of stroke in patients younger than 45 years of age, accounting for almost one fourth of strokes in this population. A history of some degree of trivial trauma is present in nearly one fourth of cases. Subsequent mortality or neurological morbidity is usually the result of distal ischemia produced by emboli released from the injury site, although local mass effect produced by arterial dilation or aneurysm formation also can occur. The gold standard for diagnosis remains digital subtraction angiography. Computed tomography angiography, magnetic resonance angiography, and ultrasonography are complementary means o evaluation, particularly for injury screening or treatment follow-up. The annual rate of stroke after injury is approximately 1% or less per year. The currently accepted method of therapy remains antithrombotic medication, either in the form of anticoagulation or antiplatelet agents; however, no class I medical evidence exists to guide therapy. Other options for treatment include thrombolysis and endovascular therapy, although the efficacy and indications for these methods remain unclear.

[Clinical treatment and therapy for dissected cervicocerebral artery]

Dissection of a cervicocerebral artery (CAD) is the second leading cause of stroke at younger ages. The pathogenesis of spontaneous CAD is not fully clarified. Defective connective tissue components may cause an arteriopathy predisposing to CAD in combination with certain trigger and risk factors. The clinical spectrum includes local pain in the neck, headaches, Horner's syndrome, isolated cranial nerve deficits, and hemispheric or brainstem infarction. Noninvasively, CAD is confirmed by Duplex sonography, MRI, and MRA. There is no controlled study for best treatment or management. Rational initial empiric treatment in acute CAD to prevent secondary embolism is partial thromboplastin time-guided anticoagulation by intravenous heparin followed by anticoagulation with warfarin. Carotid surgery for treating CAD is not recommended. The duration of anticoagulation is best guided by Doppler sonography follow-up and should extend until normalization of blood flow or at least 6 months after the vessel was occluded. Caution should be recommended for exercises that involve excessive head movements. The recurrence rate for CAD is low at <1%/year except for patients with known hereditary connective tissue disorders or in cases with familial dissections.