Acute cerebral infarcts in multiple arterial territories : The Bergen NORSTROKE study

Abstract

Introduction The majority of acute cerebral infarcts results from an occlusion of one single cerebral artery followed by loss of blood supply to the respective arterial territory. However, several independent arterial territories may be affected if more than one cerebral artery is occluded simultaneously. Acute cerebral infarcts in multiple arterial territories (MACI) account for 10 to 20 % of all ischemic strokes. MACI may have distinct pathophysiological and clinical features differing from acute cerebral infarct(s) in a single arterial territory (SACI). Aims In this dissertation, we sought to give a broad description of patients with MACI. The aim of the first two papers was to clarify pathophysiological mechanisms in regards to the etiology. In the third paper, we assessed short-term outcome and complications within the first week after the hospital admission. The fourth paper sheds light on the clinical manifestation on admission. Methods We used data from the Bergen NORSTROKE registry. We included only patients with acute cerebral infarct(s) (ACI) confirmed by diffusion-weighted magnetic resonance imaging (DWI-MRI) consecutively admitted to the stroke unit at Haukeland University Hospital. The first two papers are based on a cohort of 2125 patients admitted from 2006 to 2013. The last two papers are based on a cohort of 3343 patients admitted in an extended time frame from 2006 to 2016. MACI was defined as more than one non-continuous ischemic lesion in more than one arterial cerebral territory; either left and/or right carotid artery territory and/or basilar artery territory. Results The proportion of patients with MACI was approximately 9% of all ACI patients. The paper-I confirmed that cardiogenic embolism (CE), as defined by TOAST criteria, is the most frequent underlying etiology of MACI. The paper-II showed a positive correlation between the time from stroke onset to MRI examination and frequency of large artery atherosclerosis (LAA)-associated MACI. There was no correlation between the time from stroke onset to MRI examination and frequency of CE- 6 associated MACI. These findings suggest that CE-associated MACI occur simultaneously as a shower of emboli, while LAA-associated MACI happens rather successively over time. The paper-III showed that patients with MACI have a worse short-term outcome within the first week after the admission compared to patients with SACI. Moreover, MACI was associated with more in-hospital complications, namely deep venous thrombosis and myocardial infarction. The paper-IV showed that 72% of patients diagnosed with MACI presented with a single-territory clinical manifestation (MACI-S) on admission. MACI-S was associated with less than five ischemic lesions on DWI-MRI, involvement of the left hemisphere, and a partial anterior cerebral infarct stroke syndrome (PACI) as defined by the Oxfordshire Community Stroke Project (OCSP) classification. This finding emphasizes the essential role of MRI examination for final diagnosis of MACI. Conclusion The data presented in this dissertation show that patients with MACI differ in many clinical aspects from patients with SACI. Our findings add new knowledge to this less documented field of stroke medicine and may help to improve the diagnostic and therapeutic approaches in these patients.