Study protocol: prediction of stroke associated infections by markers of autonomic control

Exploring the Utility of Autonomic Nervous System Evaluation for Stroke Prognosis

Stroke is a major cause of functional disability and is increasing in frequency. Therefore, stroke prognosis must be both accurate and timely. Among other biomarkers, heart rate variability (HRV) is investigated in terms of prognostic accuracy within stroke patients. The literature research of two databases (MEDLINE and Scopus) is performed to trace all relevant studies published within the last decade addressing the potential utility of HRV for stroke prognosis. Only the full-text articles published in English are included. In total, forty-five articles have been traced and are included in the present review. The prognostic value of biomarkers of autonomic dysfunction (AD) in terms of mortality, neurological deterioration, and functional outcome appears to be within the range of known clinical variables, highlighting their utility as prognostic tools. Moreover, they may provide additional information regarding poststroke infections, depression, and cardiac adverse events. AD biomarkers have demonstrated their utility not only in the setting of acute ischemic stroke but also in transient ischemic attack, intracerebral hemorrhage, and traumatic brain injury, thus representing a promising prognostic tool whose clinical application may greatly facilitate individualized stroke care.

Low serum transthyretin levels predict stroke-associated pneumonia

BACKGROUND AND AIMS

Stroke-associated pneumonia (SAP) is commonly seen in ischemic stroke patients. Low transthyretin levels are found to be correlated with stroke. This study aims to investigate the potential relationship between transthyretin levels and SAP.

METHODS AND RESULTS

In total, 920 patients were involved in our study. Serum transthyretin levels were measured within 24 h at admission. We defined SAP according to the modified Centers for Disease Control criteria. In the study population, 123 (13.4%, 77 men, 46 women) were diagnosed with SAP. In the multivariable analysis, we found that serum transthyretin levels were significantly lower in SAP compared with non-SAP patients (231 ± 80 vs. 279 ± 75; P < 0.001) after adjusting for confounders. Meanwhile, we discovered that low transthyretin levels (≤252 mg/L) were independently associated with the development of SAP (OR 3.370; 95% CI: 1.763-6.441; P < 0.001). Moreover, patients with SAP had a worse clinical outcome than those without SAP at discharge. In addition, dysphagia, leukocyte count and NLR (neutrophil-to-lymphocyte ratio) were also found to be associated with SAP.

CONCLUSION

We found that low transthyretin levels significantly increased the risk of SAP. Patients with high risk of developing SAP could be early identified and prevented timely.

Clinical Correlation Analysis of Complications in Elderly Patients with Sequelae of Stroke with Different Barthel Index in Tianjin Emergency Department

OBJECTIVE

The Barthel index (BI) is the most commonly used measure of poststroke disability. The purpose of this article is to explore the different complications and severity of the sequelae of elderly stroke patients with different BI in the emergency department, so as to provide a theoretical basis for strengthening the treatment of elderly patients with stroke sequelae.

METHODS

A retrospective study was adopted, and 1896 patients were divided into two groups according to the BI: 823 patients in the bedridden group (BI ≤ 40 points) and 1073 patients in the nonbedridden group (BI > 40 points). The type and number of complications and APACHE II score were compared between the two groups.

RESULTS

Compared with the two groups, pneumonia, renal insufficiency, respiratory failure, and decubitus ulcer in the bedridden group had a higher incidence, but the incidence of upper gastrointestinal bleeding and fractures in the nonbedridden group was significantly higher (P < 0.05). The APACHE II score of the patients in the bedridden group was higher than that of the nonbedridden group, and they were critical (P < 0.001). And the number of complications was higher than that in the nonbedridden group. Moreover, the BI was negatively correlated with the APACHE-II score and the number of complications, and the APACHE II score was positively correlated with the number of complications (P < 0.001).

CONCLUSION

Different complications and severity of illness occur in elderly patients with sequelae of stroke after different BI in the emergency department.

Serum β2-Microglobulin Is Closely Associated With the Recurrence Risk and 3-Month Outcome of Acute Ischemic Stroke

Background and Purpose: Inflammation plays a significant role in the pathogenesis of acute ischemic stroke (AIS). The role of β2-microglobulin (β2M) as a potential initiator of the inflammatory response in AIS is unclear. The purpose of this study was to analyze the relationship of serum β2M with the recurrence risk and 3-month outcome of AIS.

Methods: A total of 205 patients with AIS were recruited, and their clinical and biochemical characteristics were collected. All patients were followed up for 3 months after stroke onset, and the occurrence of death or major disability at 3 months after onset was the outcome of interest in this study. We evaluated the association of serum β2M levels with the National Institute of Health Stroke Scale (NIHSS) scores, modified Rankin Scale (mRS) scores, and Essen Stroke Risk Score (ESRS) values in patients with AIS. Then, we used receiver operating curve analysis to calculate the optimal cutoff value for discriminating outcomes in patients with AIS and a binary logistic regression model to evaluate the risk factors for a poor outcome after AIS.

Results: Our results showed that serum β2M levels were significantly and positively correlated with ESRS values (r = 0.176, P < 0.001) and mRS scores (r = 0.402, P < 0.001), but the levels of β2M were not correlated with NIHSS scores (r = 0.080, P = 0.255) or with infarct volume (r = 0.013, P = 0.859). In a further study, we found that 121 patients (59.02%) had poor outcomes. The optimal β2M cutoff to predict the 3-month outcome of AIS in this study was 1.865 mg/l, and β2M was independently associated with a poor outcome at 3 months (OR = 3.325, 95% confidence interval: 1.089~10.148).

Conclusions: In conclusion, we inferred that serum β2M was positively associated with the recurrence risk and 3-month outcome of AIS, but it did not appear to be directly related to the severity of AIS or the size of the infarct at admission.

Immune changes in peripheral blood and hematoma of patients with intracerebral hemorrhage

Immunologic changes in the hematoma of patients with intracerebral hemorrhage (ICH) and the contribution of these changes to prognosis are unknown. We collected the blood samples and hematoma fluid from 35 patients with acute ICH (<30 hours from symptom onset) and 55 age-matched healthy controls. Using flow cytometry and ELISA, we found that the percentages of granulocytes, regulatory T cells, helper T (Th) 17 cells, and dendritic cells were higher in the peripheral blood of patients with ICH than in healthy controls, whereas the percentages of lymphocytes, M1-like macrophages, and M2-like macrophages were lower. Levels of IL-6, IL-17, IL-23, TNF-α, IL-4, IL-10, and TGF-β were higher in the peripheral blood of patients with ICH. The absolute counts of white blood cells, lymphocytes, monocytes, and granulocytes in the hematoma tended to be greater at 12-30 hours than they were within 12 hours after ICH, but the percentage of Th cells decreased in peripheral blood. Increased levels of IL-10 in the serum and hematoma, and a reduction in M1-like macrophages in hematoma were independently associated with favorable outcome on day 90. These results indicate that immunocytes present in the hematoma may participate in the acute-phase inflammatory response after ICH.

Acute-phase serum superoxide dismutase level as a predictive biomarker for stroke-associated infection

Background and Purpose: Oxidative stress is involved in the development of infections. However, whether oxidative stress indicators can be used as markers of stroke-associated infection (SAI) is still unclear. The purpose of this study was to test the predictive values of superoxide dismutase (SOD) and malondialdehyde (MDA) levels for SAI incidence.Methods: A total of 45 consecutive patients with ischemic stroke who were admitted to our hospital were enrolled. A prospective study was carried out to observe the occurrence of SAI during the first 7 days after stroke. Accordingly, the patients were divided into SAI and non-SAI groups. The relationship between SOD and MDA serum levels and SAI was analyzed.Results: The patients in the SAI group had significantly higher serum SOD levels than those in the non-SAI group (41.638 ± 3.428 U/ml vs. 36.542 ± 9.114 U/ml, p = 0.033). However, there were no significant differences in MDA levels between the SAI and non-SAI group (p > 0.05). The discriminating ability of serum SOD level for SAI was measured using an ROC curve. Serum level of SOD >38.16 U/ml was useful in diagnosing SAI with a sensitivity of 88% and a specificity of 61%. Kaplan-Meier curves showed that the group with serum SOD level >38.16 U/ml had higher rates of SAI incidence (χ2 = 9.688, p = 0.002; log rank test). Furthermore, Cox regression analysis indicated that a serum SOD level >38.16 U/ml was an independent risk factor for SAI (hazard ratio = 5.836; 95% CI, 1.298-26.244; p = 0.021).Conclusions: Acute-phase serum SOD level could be a predictor of SAI.

Squamous cell carcinoma antigen, platelet distribution width, and prealbumin collectively as a marker of squamous cell cervical carcinoma

BACKGROUND

Squamous cell cervical carcinoma is the most common gynecological malignant disorder worldwide. Early detection of squamous cell cervical carcinoma is needed for proper clinical management. Squamous cell carcinoma antigen (SCCA) is commonly used as a tumor marker for squamous cell cervical carcinoma. Platelet distribution width (PDW) is an indicator of platelet activation. Prealbumin is a negative acute-phase protein.

OBJECTIVE

The aim of this study was to investigate the ability of SCCA, PDW, and prealbumin individually or in combination, to distinguish between cervical carcinoma and control subjects.

MEHTODS

Two hundred and twenty patients with squamous cell cervical carcinoma and 211 control subjects were included in the study. Patients' characteristics and hematologic tests data at initial diagnosis were collected.

RESULTS

Our results showed that SCCA and PDW were higher, and prealbumin was lower in cervical carcinoma patients than in control subjects. Single biomarker had AUC value ranging from 0.753 for SCCA to 0.845 for PDW. The combination of SCCA and PDW increased the AUC to 0.900 (p< 0.0001). In addition, the combination of SCCA, PDW and prealbumin exhibited a significantly larger AUC of 0.917 (0.887-0.942), significantly higher than those of any single marker.

CONCLUSIONS

The combined use of SCCA, PDW and prealbumin can accurately distinguish squamous cell cervical carcinoma from control subjects. This promising approach could be helpful in early detection of squamous cell cervical carcinoma.

Changes in the cellular immune system and circulating inflammatory markers of stroke patients

This study was designed to investigate dynamic changes in the cellular immune system and circulating inflammatory markers after ischemic stroke. Blood was collected from 96 patients and 99 age-matched control subjects for detection of lymphocyte subpopulations and inflammatory markers. We observed decreases in B cells, Th cells, cytotoxic T cells, and NK cells and an increase in regulatory T (Treg) cells in stroke patients on days 1, 3, and 7. Serum levels of TNF-α, C-reactive protein (CRP), IL-4, IL-6, IL-10, IL-17, IL-23, and TGF-β increased, whereas serum level of IFN-γ decreased at all time points after stroke. Stroke patients with infection exhibited a similar tendency toward changes in some lymphocyte subpopulations and inflammatory markers as stroke patients without infection. After controlling for NIH Stroke Scale (NIHSS), we observed no differences in lymphocyte subpopulations between patients with anterior circulation stroke and those with posterior circulation stroke at any time point. The splenic volume correlated positively with the percentages of B cells, Th cells, and cytotoxic T cells, but negatively with Treg cells on day 3 after stroke. Infections were associated with splenic volume, leukocyte counts, percentage of Treg cells, and serum levels of CRP, IL-10, and IFN-γ on day 3. Lesion volume correlated positively with CRP, IL-6, and IL-23, but negatively with IFN-γ on day 3. The NIHSS showed a positive relation with IL-6 and IL-10 on day 3. Ischemic stroke has a profound effect on the systemic immune system that might explain the increased susceptibility of stroke patients to infection.

Serum prealbumin as an effective prognostic indicator for determining clinical status and prognosis in patients with hemorrhagic stroke

Serum prealbumin is a recognized marker of malnutrition, but its prognostic role in patients with hemorrhagic stroke remains unclear. In this study, we retrospectively reviewed the records of 105 patients with hemorrhagic stroke admitted to Renmin Hospital of Wuhan University, China, from January to December 2015. We collected demographic and radiological data, and recorded serum prealbumin levels at admission and on days 1, 3, 6, 9, and 14–21. The existence of infections and gastrointestinal hemorrhage, and clinical condition at discharge were also recorded. Serum prealbumin levels during hospitalization were significantly lower in patients with infections compared with those without infections, and also significantly lower in patients with gastrointestinal hemorrhage compared with those without. Serum prealbumin levels at discharge were significantly higher in patients with good recovery than in those with poor recovery. We conclude that regular serum prealbumin measurements in patients with hemorrhagic stroke may be a useful indicator for determining clinical status and prognosis, which may therefore help to guide clinical decision-making.

Serum prealbumin is a predictive biomarker for stroke-associated infection after an ischemic stroke

BACKGROUND

Several prior studies have linked serum prealbumin (PA) as a predictor for perioperative infection. However, whether peripheral blood PA levels can be used as an indicator of stroke-associated infection (SAI) is still unclear. In this study, we attempt to find whether serum PA is a meaningful predictor in SAI after an ischemic stroke, so as to provide theoretical basis for clinical treatment.

METHODS

Consecutive patients with acute ischemic stroke who were admitted to our hospital were enrolled and serum PA was collected. A prospective study was conducted to observe the predictive value of PA in the SAI incident in ischemic stroke patients.

RESULTS

Of 104 patients, 29 (27.9%) developed an SAI after 7 d of follow-up. The stroke with SAI group had significantly lower PA levels than the stroke without SAI group (  p < 0.05). The optimal cutoff value for predicting SAI was PA ≤ 191 mg/L, with sensitivity and specificity of 58.62% and 81.33%, respectively. Kaplan-Meier survival analysis showed that stroke patients with low serum PA level (PA ≤ 191 mg/L) had a higher SAI rates (log-rank test, χ² = 16.870, p < 0.001). Cox regression analysis showed that PA ≤ 191 mg/L (hazard ratio = 3.207; 95% CI, 1.430-7.190, p = 0.005) was an independent risk factor for SAI.

CONCLUSIONS

Early detection of serum PA during the acute phase of ischemic stroke may help us to identify at-risk SAI patients, and hence rapidly guide the intervention to prevent SAI.

Preliminary Prospective Study to Assess the Effect of Early Blood Urea Nitrogen/Creatinine Ratio-Based Hydration Therapy on Poststroke Infection Rate and Length of Stay in Acute Ischemic Stroke

BACKGROUND

This study aimed to determine whether blood urea nitrogen (BUN)/creatinine (Cr)-based hydration therapy can decrease the rate of poststroke infection and length of stay (LOS) in the neurology ward.

METHODS

This was a nonblinded, phase II single-arm prospective study with a historical control group of patients with acute ischemic stroke and a BUN/Cr ratio of 15 or higher. The study group (n = 134) received an intravenous saline bolus (300-500 mL) followed by maintenance saline (40-80 mL/hour) for the first 72 hours. The control group (n = 103) received maintenance saline infusions (40-60 mL/hour for the first 24 hours and 0-60 mL/hour for the next 24-72 hours).

RESULTS

The hydration group had a significantly lower poststroke infection rate than did the control group (7.5% versus 17.5%, P = .018) and significantly shorter LOS in the neurology ward (13.5 ± 11.6 versus 19.6 ± 14.6 days, P < .01). With regard to adverse events, two patients in each group had cerebral edema.

CONCLUSIONS

The findings suggest that the BUN/Cr ratio needs to be corrected in a timely manner in patients with acute ischemic stroke. Providing prompt saline hydration therapy based on the daily BUN/Cr ratio might decrease the poststroke infection rate and shorten LOS.

Measuring Serum Amyloid A for Infection Prediction in Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is associated with high rates of mortality and morbidity. Nosocomial infections, such as pneumonia or urinary tract infections, are among the main causes of worsening outcomes and death. The aim of this study was to discover a biomarker to predict infection in aSAH patients. For this purpose, the plasma of infected and noninfected patients was compared using quantitative mass spectrometry. The most interesting differentially expressed proteins were selected for validation by immunoassays on plasma samples taken from patients (n = 81) over 10 days of hospitalization. Predictive performances were established using Mann-Whitney U tests and receiver operating characteristic curves. Quantitative proteomics identified 17 significantly regulated proteins. Of these, levels of serum amyloid A (SAA) were significantly higher in infected patients (p < 0.007). ELISA confirmed that the concentrations were significantly higher (p < 0.002) already at hospital admission in patients who subsequently developed an infection during their hospitalization, (AUC of 76%) for a cutoff value of 90.9 μg/mL. Our data suggested that measuring SAA could be an efficient means of detecting patients susceptible of developing an infection during hospitalization after an aSAH. Its predictive capacity could lead to earlier antibiotherapy, improved patient management, and potentially better long-term outcomes.

Diagnosis of Stroke-Associated Pneumonia

Background and Purpose—

Lower respiratory tract infections frequently complicate stroke and adversely affect outcome. There is currently no agreed terminology or gold-standard diagnostic criteria for the spectrum of lower respiratory tract infections complicating stroke, which has implications for clinical practice and research. The aim of this consensus was to propose standardized terminology and operational diagnostic criteria for lower respiratory tract infections complicating acute stroke.

Methods—

Systematic literature searches of multiple electronic databases were undertaken. An evidence review and 2 rounds of consensus consultation were completed before a final consensus meeting in September 2014, held in Manchester, United Kingdom. Consensus was defined a priori as ≥75% agreement between the consensus group members.

Results—

Consensus was reached for the following: (1) stroke-associated pneumonia (SAP) is the recommended terminology for the spectrum of lower respiratory tract infections within the first 7 days after stroke onset; (2) modified Centers for Disease Control and Prevention (CDC) criteria are proposed for SAP as follows—probable SAP: CDC criteria met, but typical chest x-ray changes absent even after repeat or serial chest x-ray; definite SAP: CDC criteria met, including typical chest x-ray changes; (3) there is limited evidence for a diagnostic role of white blood cell count or C-reactive protein in SAP; and (4) there is insufficient evidence for the use of other biomarkers (eg, procalcitonin).

Conclusions—

Consensus operational criteria for the terminology and diagnosis of SAP are proposed based on the CDC criteria. These require prospective evaluation in patients with stroke to determine their reliability, validity, impact on clinician behaviors (including antibiotic prescribing), and clinical outcomes.