Effect of Posture and Fasting State on Central and Peripheral Blood Pressure in Patients With Stroke

Stroke is a leading cause of death worldwide, and is a prominent cause of chronic disability, causing significant physical, cognitive and social impairment. In the United Kingdom, there are 150,000 strokes each year, with ~900,000 people living with the debilitating effects of stroke.Individuals who experience a stroke or transient ischaemic attack (TIA; minor stroke) are at heightened risk of experiencing vascular events in the future, such as myocardial infarction, stroke and secondary TIAs, and death. Of all the measures of interest, greater blood pressure control is the most important contributor to positive health outcomes in stroke patients. However, clinical practice, and research to date concentrate on the assessment of peripheral blood pressure assessments (the blood pressure as identified from the arm). The measurement of central haemodynamic parameters, including central systolic blood pressure (cSBP) and arterial wave reflection (i.e., augmentation index, AIx), hold the potential to provide clinicians with important diagnostic and prognostic information beyond that provided by traditional peripheral blood pressure readings. The assessment of central blood pressure is important as it reflects the stress and loading on the left ventricle and coronary arteries. Considering the marked differences in pulse pressure between the central aorta and peripheral limbs, peripheral blood pressure may not accurately reflect the effects of peak arterial blood pressure on centrally located organs. Previous research has demonstrated central blood pressures to be 50 % superior to peripheral blood pressures when predicting cardiovascular events, while in comparison to peripheral blood pressure, central blood pressure may improve the management of hypertension. Owing to recent technological advances, central haemodynamic parameters can be obtained quickly and noninvasively using an automated blood pressure cuff (oscillometer).While the validity of these devices which measure central haemodynamic parameters has been demonstrated, further study is required to determine measurement precision (reliability) under normal clinical operating conditions (i.e. , in the hospital or general practioner setting). As such, this study will assess the influence of fasting status (fasted vs. nonfasted) and posture (seated vs. supine) on central and peripheral blood pressure measures in patients diagnosed with stroke. The study will determine whether these parameters can be reliably assessed and whether stroke severity (major stroke, minor stroke, TIA) influences the reported results.

Design and setting:

This study is a single centre observational study. All stroke/TIA patients will be recruited from the Royal Hampshire County Hospital within the Hampshire Hospital NHS Foundation Trust (HHFT).

Patients will be recruited from the inpatient and outpatient setting. For patients diagnosed with a major or minor stroke and who have not been discharged from the hospital, recruitment will take place on the acute stroke ward at the hospital. For these patients, all assessments will also be undertaken within the hospital as patients will be based in the acute stroke ward. For those patients identified with minor stroke or TIA within the emergency department or outpatient setting (i.e., stroke clinics), and who not be staying in the acute stroke ward, will be recruited from these settings. All assessments with these patients will take place in the Physiology Laboratory at the University of Winchester. Written informed consent will be obtained from all participants.

All stroke (minor and major) patients will be assessed using the National Institute of Health Stroke Severity Scale (NIHSS). All patients with suspected TIA with be assessed with the ABCD2. Participants will comply with pharmacological treatment as recommended.