A Transcranial Doppler Study of Vasomotor Reactivity in Symptomatic Carotid Occlusion

Abstract

A group of 30 patients with symptomatic internal carotid artery (ICA) occlusion and different computed tomography (CT) patterns of cerebral ischemia (14 borderzone and/or terminal, 16 territorial) were studied by means of transcranial Doppler (TCD) to determine the relationship between vasomotor reactivity and the topography of the infarct on CT scan. The vasomotor reactivity was evaluated by assessing the mean flow velocity changes observed in the middle cerebral artery (MCA) after the longest possible apnea and i.v. Diamox injection (12–15 mg/kg body weight). An impairment in the vasomotor response was found in 13 out of 14 patients with borderzone and/or terminal ischemia but in only 1 out of 16 with complete territorial ischemia. No relationship with the basal MCA flow velocity was observed. Diamox and apnea tests in TCD examination can be considered useful tools for investigating the hemodynamic changes following ICA occlusion.

Cerebral vasomotor reactivity of patients with acute ischemic stroke: Cortical versus subcortical infarcts: An Israeli–Turkish collaborative study

“…VMR% was evaluated by recording the percent differences in peak systolic BFV in each MCA at baseline and after Diamox administration. An intravenous (IV) injection of 1.0 g acetazolamide was given over 5 min, and the MCA BFVs were again measured with the ultrasound sample volume at the same depth 20 min later [6]. Table 1 Demographics and risk factor profiles in the cortical (CI) and subcortical (SI) brain infarct groups …”

“…VMR is defined as a shift between cerebral blood flow (CBF) or cerebral blood flow velocity (BFV) before and after administration of a potent vasodilatory stimulus test. VMR of the middle cerebral artery (MCA) was frequently assessed in patients with extracranial carotid occlusive disease, and several studies showed that highgrade stenosis or occlusion of the internal carotid artery (ICA) can significantly reduce VMR of the ipsilateral MCA [3][4][5][6]. Furthermore, the predictive value of impaired VMR for ischemic stroke occurrence was convincingly confirmed in subjects with carotid occlusive disease [7][8][9][10][11].…”

Differential Hemodynamic Response to Repetitive Transcranial Magnetic Stimulation in Acute Stroke Patients with Cortical versus Subcortical Infarcts

“…CBF velocity (CBFV) measured on transcranial Doppler (TCD) in the major cerebral arteries reflects CBF, and is thus often used to assess vasomotor reactivity [2]. Reduced vasomotor reactivity has frequently been demonstrated in studies on patients with chronic extracranial carotid occlusive disease [3,4], and this correlates with the risk of stroke [5,6]. Only a few studies, however, exist on vasomotor response to hypercapnia assessed by change in CBFV in acute ischemic stroke patients who do not have carotid occlusive disease [7,8,9].…”

Cerebral bloodflow and oxygen metabolism in borderzone and territorial infarcts due to symptomatic carotid artery occlusion

“…It remains controversial whether borderzone infarcts are due to impaired cerebral perfusion and whether territorial infarcts are caused by artery‐to‐artery emboli in case of occlusion of the internal carotid artery (Torvik and Skullerud, 1982; Bogousslavsky and Regli, 1986a; Weiller et al. , 1991a; Provinciali et al. , 1993; Baumgartner and Regard, 1994; Klijn et al.…”