20-Hydroxyeiscosatetraenoic Acid May Be as a Predictor of Malignant Middle Cerebral Artery Infarction in Patients With Massive Middle Cerebral Artery Infarction

Abstract

Background

Early identification of massive middle cerebral artery infarction (MCAI) at risk for malignant MCAI (m-MCAI) may be useful in selecting patients for aggressive therapies. The aim of this study was to determine whether CYP metabolites may help to predict impending m-MCAI.

Methods

This is a prospective, two-center observational study in 256 patients with acute massive MCAI. Plasma levels of 20-hydroxyeicosatetraenoic acid (20-HETE), epoxyeicosatrienoic acids, and dihydroxyeicosatrienoic acids were measured at admission. Brain computed tomography (CT) was performed at admission and repeated between days 3 and 7, or earlier if there was neurological deterioration. The primary outcome was m-MCAI. m-MCAI was diagnosed when follow-up brain CT detected a more than two-thirds space-occupying MCAI with midline shift, compression of the basal cisterns, and neurological worsening.

Results

Among 256 patients, 77 (30.1%) developed m-MCAI, 60 (77.9%) patients with m-MCAI died during 3 months of stroke onset. 20-HETE level on admission was significantly higher in patients with m-MCAI than those without m-MCAI. There was an increase in the risk of m-MCAI with increase of 20-HETE levels. The third and fourth quartiles of 20-HETE levels were independent predictors of m-MCAI (OR: 2.86; 95% CI: 1.16 – 6.68; P=0.025, and OR: 4.23; 95% CI: 1.35 – 8.26; P=0.002, respectively).

Conclusions

Incidence of m-MCAI was high in patients with massive MCAI and the prognosis of m-MCAI is very poor. Elevated plasma 20-HETE may be as a predictor for m-MCAI in acute massive MCAI, and it might useful in clinical practice in therapeutic decision making.

Background

Massive middle cerebral artery (MCA) infarction (MCAI) accounts for 10% to 15% of all stroke patients, which usually caused by acute occlusion of internal carotid artery or the proximal MCA [1, 2], and of these patients, malignant MCAI (m-MCAI) reaches 30% to 50% [2, 3, 4]. The m-MCAI is the most devastating form of ischemic stroke, is characterized with large supratentorial infarcts and space-occupying brain edema followed by cerebral herniation [2, 5]. The mortality is approximately 80% in m-MCAI patients, and those patients who survive experience severe disabilities [6, 7]. Decompressive hemicraniectomy (DHC) is recommended when it is performed within 48 hour after stroke onset in patients with m-MCAI [8, 9]. Therefore, early identification or prediction of m-MCAI is very essential for timely application of DHC in patients with massive MCAI.

 It is noted that not all patients with massive MCAI would develop m-MCAI [2, 4, 10, 11, 12]. Therefore, identification of key mechanisms involved in m-MCAI and predictors for m-MCAI will be of important significance for the early diagnosis and treatment of m-MCAI among patients with massive MCAI. For the last two decades, prediction of m-MCAI using radiological variables, clinical risk factors, and molecular markers has been thoroughly investigated [2-4, 8, 13, 14]. However, the underlying basic mechanisms and predictors for m-MCAI are not completely understood.

The loss of integrity of the endothelial basal lamina and blood-brain barrier (BBB) disruption are believed to be the important cause of edema after focal cerebral ischemia. Arachidonic acid (AA) is a membrane fatty acid that can be metabolized into 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) by cytochrome P450 (CYP) ω-hydroxylase and CYP epoxygenases, respectively, and EETs are then metabolized to yield less biologically active dihydroxyeicosatrienoic acids (DiHETEs) by soluble epoxide hydrolase (sEH) [15]. 20-HETE and EETs have inflammatory activities [16]. Meanwhile, 20-HETE, as a potent vasoconstrictor, has been shown in the cerebral vasculature of the stroke-prone spontaneously hypertensive rat and contributes to stroke severity [17]. EETs play an important role in neuroprotection and cerebral blood flow regulation after brain injury [18]. Our previous studies demonstrated that CYP metabolite levels were associated with early neurologic deterioration and functional outcome, and may be as a predictor for early neurologic deterioration in acute ischemic stroke [19, 20]. However, although considerable advances have been made, the association of CYP metabolites with m-MCAI development has not been definitely determined.

In this study, we hypothesized that levels of early CYP metabolites (eg, 20-HETE, EETs and DiHETEs) could predict m-MCAI. Therefore, we conducted a prospective, two-center observational study that aimed to explore potential CYP metabolites involved in the m-MCAI and to elucidate their possible mechanisms in m-MCAI development.

Materials And Methods

Study population

This study was conducted in People’s Hospital of Deyang City, the First Affiliated Hospital of Wenzhou Medical University and the Third Affiliated Hospital of Wenzhou Medical University. The study protocol was approved by the Ethics Committee at the participating hospitals. Written informed consent was obtained from each patient prior to study enrollment or from their legal representative if the patient had lost the capacity to give informed consent.

Between October 2011 and September 2014, we registered 1542 patients who had suffered their first-ever stroke and were admitted to above two participating hospitals. Data were recorded at the time of assessment using a standardized structured form. Detailed methods for data collection of the patients were described in our previous articles [14, 21]. In this study, we enrolled patients who were admitted within 48 hour of the onset of stroke, and suffered from massive MCAI, which was defined as > 50% of the MCA territory on early cranial computed tomography (CT) or magnetic resonance imaging (MRI) scans, with or without the involvement of the adjacent territories [14, 22]. The patients with incomplete hospital records or missing imaging, preexisting score of more than 2 on the modified Rankin scale (mRS), patients included in clinical trials or treated with thrombectomy, and unwilling to participate in this study were excluded. According to aforementioned inclusion criteria and exclusion criteria, a total of 256 patients with massive MCA infarction were enrolled, the detailed data cleaning procedure was presented in Figure 1.

All enrolled patients had an initial brain CT scan at admission. Early signs of cerebral infarction on CT included: (1) the presence of focal hypodensity consistent with the clinical findings; (2) obscuration of the lenticular nucleus or the cortex, or mass effect with effacement of the cortical sulci (grade I); (3) ventricular asymmetry (grade II); (3) shifting of the structures of the median line (grade III) [23]. For the extent of MCAI, Alberta Stroke Program Early CT Score (ASPECTS) was evaluated in the first CT examination [24]. A second CT or MRI was performed between 3 days and 7 days of hospitalization to measure the infarct volume. The infarct volume was determined using the formula 0.5×a×b×c (where a and b are the largest perpendicular diameters measured and c is the sum of slices multiplied with thickness on CT or diffusion-weighted imaging on MRI). An additional CT scan was performed to determine brain edema or hemorrhagic transformation whenever patients had neurological deterioration. Assessment of brain CT or MRI was conducted by a neuroradiologist who was blinded to clinical picture.

For each patient, stroke severity was assessed using National Institutes of Health Stroke Scale (NIHSS) by a member of stroke team on admission, and subsequently on a daily during the period of hospitalization. Age, sex, onset to admission time, baseline systolic and diastolic blood pressure were recorded. Vascular risk factors were investigated. Serum glucose, triglycerides (TG), total plasma cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) were measured. Dyslipidemia was defined as TG > 180 mg/dL, TC > 200 mg/dL or use of lipid-lowering medication [19]. Stroke subtypes were classified as atherothrombosis, cardioembolism, stroke of other determined etiology, and stroke of undetermined etiology according to the new subtype classification criteria [25]. All enrolled patients received standard therapies based on standard guidelines [9].

Measurement of plasma 20-HETE, EETs and DiHETEs levels

Whole blood (4ml) was drawn from each patient at adimission. Plasma was isolated following centrifugation and samples were stored at −80 ^◦C until analysis. Total plasma EETs and DiHETEs levels were measured using a stable isotope dilution GC/MS following base hydrolysis and separation on high performance liquid chromatography (HPLC), and plasma 20-HETE level was analyzed using a stable isotope dilution gas chromatography/mass spectrometer (GC/MS), as described in our previous studies [19, 20].

Assessment of m-MCAI and clinical outcome

The primary outcome of this study was m-MCAI. m-MCAI was diagnosed according to the following criteria [13, 26]: massive MCAI showed on follow-up CT including more than two-thirds space-occupying MCAI with midline shift and compression of the basal cisterns, and further consciousness status declined at least 1 point of consciousness item described in the NIHSS compared with the baseline consciousness status on admission, or deterioration of neurological status with clinical signs of uncal herniation and mass effect leading to early death or DHC.

All patients were followed up at 3 months after stroke onset by a certified stroke team member using questionnaires via telephone interview. The secondary outcomes were vascular death and modified Rankin Scale (mRS) at 3 months. Vascular death was defined as vascular mortality due to coronary heart disease, ischemic stroke, or other vascular causes. A favorable outcome was considered as mRS ≤ 2 points, while mRS >2 points was defined as a unfavorable outcome, as described in our previous studies [14, 19- 21].

Statistical analysis

Previous studies have shown prevalence of m-MCAI to be approximately 30% - 50% in patients with massive MCAI [2-4]. According to this estimate, we expected a minimum sample size requirement of 250 patients with massive MCAI for determining the difference in prevalence of m-MCAI within ± 15% with 95% confidence intervals (CI) [20, 27].

The results are expressed as percentages for categorical variables, and continuous variables are expressed as mean ± Standard Deviation. Baseline and clinical characteristics were compared using χ² test or Fisher exact test (categorical variables) and the Student t test (continuous variables) between patients with and without m-MCAI. We calculated 20-HETE by quartiles of increasing levels to evaluate for possible threshold effects for m-MCAI.

Multiple logistic regression analysis was used to assess the possible contributing factors for m-MCAI using variables with P values < 0.05 in univariate analysis, and reported as odds ratio (OR) with the 95% confidence intervals (CI). Furthermore, Cox proportional hazard model was performed to account for the probability of m-MCAI according to the 20-HETE levels levels, and reported using Kaplan-Maier curve.

All statistical analyses were performed using SPSS 16.0 (SPSS Inc., Chicago, IL, USA). All tests were two sided, and the threshold level of P < 0.05 was defined as statistical significance.

Results

We prospectively registered 1542 patients with ischemic stroke who were admitted within 48 hour of the onset of stroke between October 2011 and September 2014. Of those, 256 patients were massive MCAI. Seventy-seven of the 256 patients (30.1%) developed m-MCAI (60 of 77 patients [77.9%] occurred in the first 72 hour, all occurred within 7 days after admission), 179 patients (69.9%) did not experience m-MCAI. Baseline clinical characteristics in patients with and without m-MCAI were presented in Table 1. Compared with patients without m-MCAI, younger age, atrial fibrillation, left MCAI, and subtype of cardio-embolism were significantly more frequent in patients with m-MCAI. For in-hospital management, patients with m-MCAI more frequently used mechanical ventilation (35.1% vs. 1.7%, P <0.001) and decompressive surgery (27.2% vs. 1.7%, P <0.001) than patients without m-MCAI (Table 1). There were no significant differences in other clinical characteristics between patients with and without m-MCAI (Table 1).

Unfavorable outcome (mRS >2) was significantly more frequent in patients with m-MCAI than those without m-MCAI. Sixty of patients (77.9%) with m-MCAI died during 3 months of stroke onset, and only 3 (3.9%) of the survivors were independent (mRS ≤2) at 3 months. Among the patients without m-MCAI, 75 (41.9%) patients were dead during 3 months, and 51 (25.5%) were independent at 3 months (Table 1).

Early signs of cerebral infarction on CT scan at admission were detected more frequently in patients who later developed m-MCAI than those did not experience m-MCAI (89.6 % vs. 77.8%; P = 0.045, Table 2). Severe mass effect (grade II and III) and extent of MCAI (ASPECTS) on CT scan at admission, and final infarct volume >145 cm³ at second CT scan were significantly more frequent in m-MCAI group than non m-MCAI group (Table 2).

The mean 20-HETE level was 1924.6 ± 194.8 pmol/L in patients with m-MCAI, and 1698.7 ± 173.5 in patients without m-MCAI at admission (P < 0.001, Table 2). There were no significant differences of EETs and DiHETEs levels between two groups (P > 0.05, Table 2). The mean 20-HETE level was 1789 ± 174.6 pmol/L in 256 patients with massive MCAI, with quartile levels as follows: 826 to 1456 pmol/L (first quartile, n=48); 1457 to 1768 pmol/L (second quartile n=78); 1769 to 2024 pmol/L (third quartile, n=76); and 2025 to 2737 pmol/L (fourth quartile, n=54). The incidence of m-MCAI increased with increasing quartile levels of 20-HETE (0% [0/48], 14.1% [11/78], 35.5% [27/76], and 72.2% [39/54] in patients from first quartile to fourth quartile, respectively, P < 0.001).

20-HETE levels and final infarct volume >145 cm³ were found to be independent predictors of m-MCAI after adjusting the covariates (Table 3). The odds ratio for m-MCAI increased with increase in quartiles of 20-HETE level, using the first quartile as the reference, the third and fourth quartiles of 20-HETE levels were found to be independent predictors of m-MCAI (OR: 2.86; 95% CI: 1.16 – 6.68; P=0.025, and OR: 4.23; 95% CI: 1.35 – 8.26; P=0.002, respectively, Table 3). Cox proportional hazard curve is showed in the Figure 2, there was an increase in the risk of m-MCAI with higher level of 20-HETE (HR: 3.82, 95% CI: 1.54 – 9.23, P = 0.001 (log- rank test).

Discussion

The present results showed that the incidence of m-MCAI was very high in patients with massive MCAI (30.1%). Furthermore, 20-HETE level was independent predictor of m-MCAI after adjusting the covariates, the odds ratio for m-MCAI increased with increase in quartiles of 20-HETE levels, this may be of use in therapeutic decision making and the timing of DHC [28]. 

In recent decades, clinical risk factors, neuroimaging variables, and molecular markers have been thoroughly investigated for prediction of m-MCAI [2-4, 8, 13-14]. However, the sensibility and specificity of these markers for prediction of m-MCAI are insufficient. Some studies revealed that the sensitivity of brain CT scan was high, while the specificity was low for identifying m-MCAI [23, 29]. In present study, we found that prevalence of early signs of cerebral infarction and mass effect (grade II and grade III) was more prevalent, and ASPECTS was significantly lower on CT scan at admission in patients who later developed m-MCAI than those did not experience m-MCAI. However, these neuroimaging variables were not independent predictors of m-MCAI. Our results were in accordance with other previous studies [5, 8, 23, 29]. Some other studies and current results also indicated that clinical factors were not sufficient to identify patients with impending malignant brain edema and m-MCAI [2, 14]. In recent study, promising results have been obtained from neuroimaging tests such as single-photon emission CT and diffusion-weighted MRI in the prediction of m-MCAI [30]. Although these techniques are most reliable predictor for m-MCAI quickly and accurately, they are unable to directly predict the development of massive brain edema.

The underlying basic mechanisms of m-MCAI are not completely understood. The loss of integrity of the endothelial basal lamina and BBB disruption play key roles in pathophysiological mechanisms of malignant edema formation after massive MCAI. In this study, we found that elevated plasma 20-HETE may be as an independent predictor for m-MCAI in acute massive MCAI, and this is the first to identify a positive relationship between 20-HETE levels and m-MCAI.

20-HETE, as a potent vasoconstrictor, is associated with cerebral ischemia injury, cerebral edema, and unfavorable outcomes after subarachnoid hemorrhage [31]. The increase of vascular permeability and subsequent extravasation of serum components is one of principal causes in development of brain edema after ischemic stroke. 20-HETE can regulate cerebral vascular tone, constrict cerebral arteries, and increase vascular permeability by activating intracellular protein kinase C signaling pathway [32], which is involved in apoptosis or cell death [33]. Neuronal apoptosis is an important mechanism of brain ischemic damage in animal experiments [34], and is associated with mortality and poor functional prognosis after ischemic stroke [35]. 20-HETE may also injure vascular smooth muscle cells and endothelial cells by inhibition of Na⁺, K⁺ - ATPase activity and large-conductance Ca²⁺ - sensitive K⁺ channel, and increase of Ca²⁺ influx via L-type Ca2⁺ channels [36]. In addition, 20-HETE promote formation of oxygen radicals, which may cause endothelial injury [37, 38]. Inhibitor of 20-HETE can reverse the decrease of cerebral blood flow following subarachnoid hemorrhage and reduce infarct size after transient cerebral ischemia in animal experiments [39, 40]. All of these previous studies suggest a potential molecular mechanism of 20-HETE might lead to m-MCAI after acute massive MCAI.

Despite our findings are interesting, several limitations of this study should be noted. First, this was a two-center study, the samples were small. Therefore, our current findings should be validated in larger samples, multi-center studies. Second, plasma CYP metabolite levels may dynamic changes after ischemic stroke. Blood samples for CYP metabolites were drawn from each patient at admission. We did not measure plasma CYP metabolite levels during follow-up in non-surviving and surviving patients. Third, m-MCAI could be better detected if brain CT scan were consistently undertaken earlier, or repeated every 48 hour. However, brain CT scan was performed at admission and repeated between 3 days and 7 days of hospitalization or when patients had neurological deterioration in this study. Therefore, further well designed studies are needed to confirm our current findings.

Conclusion

The incidence of m-MCAI was very high in patients with massive MCAI, the prognosis of m-MCAI is very poor. Elevated plasma 20-HETE may be as a predictor for m-MCAI in acute massive MCAI. Our findings may be useful in clinical practice in therapeutic decision making and the timing of DHC.

Abbreviations

MCAI,massive middle cerebral artery infarction; m-MCAI, malignant MCAI; DHC, decompressive hemicraniectomy; 20-HETE, 20-hydroxyeicosatetraenoic acid; CT, computed tomography; ASPECTS, Alberta Stroke Program Early CT Score; BBB, blood-brain barrier; CYP, cytochrome P450; EETs, epoxyeicosatrienoic acids; sEH, soluble epoxide hydrolase; MRI, magnetic resonance imaging; mRS, modified Rankin scale; TG, triglycerides; TC, total plasma cholesterol; LDL-C, low-density lipoprotein cholesterol; CI, confidence intervals; OR, odds ratio.

Declarations

Acknowledgments

None.

Funding

This study was supported in part by grants from the Sichuan Science and Technology Agency Research Foundation (Grant No.2018JY0164), the Scientific Research Foundation of Sichuan Provincial Health Department (Grant No. 16ZD046). The funding body did not participate in the design of the study; collection, analysis, and interpretation of data; and in writing the manuscript.

Availability of data and materials

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Authors’ contributions

XY participated in the design of the study and drafted the manuscript. QZ participated in the design of the study and statistical analysis. JL and BM participated in the design of the study, brain computed tomography and magnetic resonance imaging. JL and T wrote the main manuscript text. QZ and JL participated to evaluate patients. All authors reviewed and approved the final manuscript.

Ethics approval and consent to participate

The study protocol was submitted to and approved by the Ethics Committee of the People’s Hospital of Deyang City, the Affiliated Hospital of Southwest Medical University, and Suining Central Hospital. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Written informed consent was obtained from all individual participants included in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

References

1. Moulin DE, Lo R, Chiang J, Barnett HJM. Prognosis in middle cerebral artery occlusion. Stroke. 1985;16:282-284.
2. Huttner HB, Schwab S. Malignant middle cerebral artery infarction: clinical characteristics, treatment strategies, and future perspectives. The Lancet Neurology. 2009;8:949-58.
3. Kasner SE, Demchuk AM, Berrouschot J, Schmutzhard E, Harms L, Verro P, et al. Predictors of fatal brain edema in massive hemispheric ischemic stroke. Stroke. 2001;32:2117-2123.
4. Dohmen C, Bosche B, Graf R, Staub F, Kracht L, Sobesky J, et al. Prediction of malignant course in MCA infarction by PET and microdialysis. Stroke. 2003;34:2152-2158.
5. Berrouschot J, Sterker M, Bettin S, Köster J, Schneider D. Mortality of space-occupying ('malignant') middle cerebral artery infarction under conservative intensive care. Intensive Care Med.1998;24:620-623.
6. Hacke W, Schwab S, Horn M, Spranger M, De Georgia M, von Kummer R. “Malignant” middle cerebral artery territory infarction: clinical course and prognostic signs. Arch Neurol. 1996;53:309-315.
7. Steiner T, Ringleb P and Hacke W. Treatment options for large hemispheric stroke. Neurology. 2001; 57(Suppl.2): S61-S68.
8. Minnerup J, Wersching H, Ringelstein EB, Heindel W, Niederstadt T, Schilling M, et al. Prediction of malignant middle cerebral artery infarction using computed tomography-based intracranial volume reserve measurements. Stroke. 2011;42:3403-3409.
9. Powers WJ, Rabinstein AA, Ackerson T, Adeoye OM, Bambakidis NC, Becker K, et al. 2018 Guidelines for the Early Management of Patients With Acute Ischemic Stroke: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. 2018;49:e46-e110.
10. Neugebauer H, Jüttler E. Hemicraniectomy for malignant middle cerebral artery infarction: current status and future directions. Int J Stroke. 2014; 9:460-467.
11. Frank JI. Large hemispheric infarction, deterioration, and intracranial pressure. Neurology. 1995;45:1286-1290.
12. Qureshi AI, Suarez JI, Yahia AM, Mohammad Y, Uzun G, Suri MF, et al. Timing of neurologic deterioration in massive middle cerebral artery infarction: a multicenter review. Crit Care Med. 2003;31:272-277.
13. Zhou Z, Zhang J, Li X, Xia C, Han Y, Chen H. Protein microarray analysis identifies key cytokines associated with malignant middle cerebralartery infarction. Brain Behav. 2017;7:e00746.

14. Li J, Zhang P, Wu S, Yi X, Wang C, Liu M. Factors associated with favourable outcome in large hemispheric infarctions. BMC Neurol. 2018;18:152. 
15. 15. Zeldin DC. Epoxygenase pathways of arachidonic acid metabolism. J Biol Chem. 2001; 276:36059-36062.
16. Calder PC. Polyunsaturated fatty acids and inflammatory processes: New twists in an old tale. Biochimie. 2009;91:791-795.
17. Dunn KM, Renic M, Flasch AK, Harder DR, Falck J, Roman RJ. Elevated production of 20-HETE in the cerebral vasculature contributes to severity of ischemic stroke and oxidative stress in spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol.2008;295:H2455-H2465.
18. Imig JD, Simpkins AN, Renic M, Harder DR. Cytochrome P450 eicosanoids and cerebral vascular function. Exp Rev Mol Med. 2011; 13: e7.
19. Yi X, Han Z, Zhou Q, Lin J, Liu P. 20-Hydroxyeicosatetraenoic Acid as a Predictor of Neurological Deterioration in Acute Minor Ischemic Stroke. Stroke. 2016;47:3045-3047.
20. Yi X, Lin J, Li J, Zhou Q, Han Z. Epoxyeicosatrienoic Acids are Mediated by EPHX2 Variants and may be a Predictor of Early Neurological Deterioration in Acute Minor Ischemic Stroke. J Atheroscler Thromb. 2017;24:1258-1266.
21. Yi X, Lin J, Wang C, Zhang B, Chi W. Low-molecular-weight heparin is more effective than aspirin in preventing early neurologic deterioration and improving sixmonth outcome. J Stroke Cerebrovasc Dis. 2014;23:1537-1544.
22. Uhl E, Kreth FW, Elias B, Goldammer A, Hempelmann RG, Liefner M, et al. Outcome and prognostic factors of hemicraniectomy for space occupying cerebral infarction. J Neurol Neurosurg Psychiatry. 2004; 75: 270-274.
23. Serena J, Blanco M, Castellanos M, Silva Y, Vivancos J, Moro MA, et al. The prediction of malignant cerebral infarction by molecular brain barrier disruption markers. Stroke. 2005;36:1921-1926.

24. Pexman JH, Barber PA, Hill MD, Sevick RJ, Demchuk AM, Hudon ME, et al. Use of the Alberta Stroke Program Early CT Score (ASPECTS) for assessing CT scans in patients with acute stroke. AJNR Am J Neuroradiol. 2001;22:1534-1542.
25. Han SW, Kim SH, Lee JY, Chu CK, Yang JH, Shin HY, et al. A new subtype classification of ischemic stroke based on treatment and etiologic mechanism. Eur Neurol. 2007;57:96-102.
26. Schwab S, Steiner T, Aschoff A, Schwarz S, Steiner HH, Jansen O, et al. Early hemicraniectomy in patients with complete middle cerebral artery infarction. Stroke. 1998;29:1888-1893.
27. Lwanga SK, Lemeshow S. Sample Size Determination in Health Studies: A Practical Manual. Geneva: World Health Organization; 1991.
28. Kilic M, Ertem DH, Ozdemir B. Timing of Decompressive Craniectomy for Malignant Middle Cerebral Artery Infarction: A Single-Center Analysis. Medicina (Kaunas).2019;55(2). pii: E31. doi: 10.3390/medicina55020031.
29. von Kummer R, Meyding-Lamade U, Forsting M, Rosin L, Rieke K, Hacke W, et al. Sensitivity and prognostic value of early CT in occlusion of the middle cerebral artery trunk. AJNR Am J Neuroradiol. 1994;15:9-15.
30. Pallesen LP, Barlinn K, Puetz V. Role of Decompressive Craniectomy in Ischemic Stroke. Front Neurol. 2019 Jan 9;9:1119. doi: 10.3389/fneur.2018.01119. eCollection 2018.
31. Donnelly MK, Crago EA, Conley YP, Balzer JR, Ren D, Ducruet AF, et al. 20-HETE is associated with unfavorable outcomes in subarachnoid hemorrhage patients. J Cereb Blood Flow Metab.2015; 35:1515-1522.
32. Lange A, Gebremedhin D, Narayanan J, Harder D. 20-Hydroxyeicosatetraenoic acid-induced vasoconstriction and inhibition of potassium current in cerebral vascular smooth muscle is dependent on activation of protein kinase C. J Biol Chem. 1997; 272: 27345-27352.
33. Randriamboavonjy V, Busse R, Fleming I. 20-HETE induced contraction of small coronary arteries depends on the activation of Rho-kinase. Hypertension. 2003;41:801-806.
34. Sairanen T, Karjalainen-Lindsberg ML, Paetau A, Ijäs P, Lindsberg PJ. Apoptosis dominant in the periinfarct area of human ischaemic stroke--a possible target of antiapoptotic treatments. Brain.2006;129:189-199.
35. Gomez-Sanchez JC, Delgado-Esteban M, Rodriguez-Hernandez I, Sobrino T, Perez de la Ossa N, Reverte S,  et al. The human Tp53 Arg72Pro polymorphism explains different functional prognosis in stroke. J Exp Med.2011; 208:429-437.
36. Cheng J, Ou JS, Singh H, Falck JR, Narsimhaswamy D, Pritchard KA Jr, et al. 20-Hydroxyeicosatetraenoic acid causes endothelial dysfunction via eNOS uncoupling. Am J Physiol Heart Circ Physiol. 2008; 294:H1018-1026.
37. Guo AM, Arbab AS, Falck JR, Chen P, Edwards PA, Roman RJ, et al. Activation of vascular endothelial growth factor through reactive oxygen species mediates 20-hydroxyeicosatetraenoic acid-induced endothelial cell proliferation.J Pharmacol Exp Ther. 2007;321:18-27.
38. Singh H, Cheng J, Deng H, Kemp R, Ishizuka T, Nasjletti A, et al. Vascular cytochrome P450 4A expression and 20-hydroxyeicosatetraenoic acid synthesis contribute to endothelial dysfunction in androgen-induced hypertension. Hypertension. 2007;50:123-129.
39. Takeuchi K, Renic M, Bohman QC, Harder DR, Miyata N, Roman RJ. Reversal of delayed vasospasm by an inhibitor of the synthesis of 20-HETE. Am J Physiol Heart Circ Physiol. 2005;289:H2203-H2211.
40. Tanaka Y, Omura T, Fukasawa M, Horiuchi N, Miyata N, Minagawa T, et al.  Continuous inhibition of 20-HETE synthesis by TS-011 improves neurological and functional outcomes after transient focal cerebral ischemia in rats. Neurosci Res. 2007; 59:475-480.

Tables

Table 1. Baseline clinical characteristics in patients with and without m-MCAI.

m-MCAI, malignant middle cerebral artery infarction; MCA, middle cerebral artery；NIHSS, National Institutes of Health Stroke Scale；SBP, systolic blood pressure; DBP, diastolic blood pressure; tPA, tissue plasminogen activator; mRS, modified Rankin Scale.

Table 2. Neuroimaging finding and plasma CYP450 metabolite levels on admission in patients with and without m-MCAI. 

m-MCAI, malignant middle cerebral artery infarction; CT, computed tomography; ASPECTS, Alberta Stroke Program Early CT Score; CYP450, cytochrome P450; HETE, hydroxyeicosatetraenoic acid; DiHETEs, dihydroxyeicosatrienoic acids; EET, epoxyeicosatrienoic acids.

Table 3. Predictors of m-MCAI and odds ratio according to 20-HETE quartiles

m-MCAI, malignant middle cerebral artery infarction; MCA, middle cerebral artery；HETE, hydroxyeicosatetraenoic acid; CI, confidence intervals; OR, odds ratio; CT, computed tomography; ASPECTS, Alberta Stroke Program Early CT Score.