Rationale and Design for the LOnger-term effects of SARS-CoV-2 INfection on blood Vessels And blood pRessure (LOCHINVAR): an observational phenotyping study.

Introduction: COVID-19 may lead to long-term endothelial consequences including hypertension, stroke and myocardial infarction. A pilot study 'COVID-19 blood pressure endothelium interaction study', which found that patients with normal blood pressure (BP) at the time of hospital admission with COVID-19 showed an 8.6 mm Hg higher BP ≥12 weeks after recovery, compared with a group without COVID-19. The 'LOnger-term effects of SARS-CoV-2 INfection on blood Vessels And blood pRessure'(LOCHINVAR) study is designed to provide definitive evidence of the long-term impact of COVID-19 on BP.

Methods And Analysis: The LOCHINVAR study is an observational clinical phenotyping study comparing longitudinal BP change between individuals with and without COVID-19 infection. 150 participants (30-60 years) with no history of hypertension and not on BP lowering medications will be recruited to the study to attend three visits (baseline, 12 months, 18 months). Cases will be patients who were admitted to the Queen Elizabeth University Hospital (QEUH), Glasgow, UK, with suspected/confirmed COVID-19 until 31 December 2021 and who were alive at discharge. Controls will be those who have never had confirmed COVID-19 infection. All participants will undergo clinical and vascular phenotyping studies which will include 24-hour ambulatory BP monitoring systolic BP (ABPM SBP), brachial flow-mediated dilatation urine and blood samples to assess the renin-angiotensin system, vascular inflammation and immune status. The primary outcome is the change in systolic 24-hour ABPM (ABPM SBP) between the cases and controls. Sample size was calculated to detect a mean difference of 5 mm Hg ABPM SBP at 80% power.

Ethics And Dissemination: The protocol of this study has been approved by the West of Scotland Research Ethics Committee 5 (21/WS/0075), Scotland, UK. Written informed consent will be provided by all study participants. Study findings will be submitted to international peer-reviewed hypertension journals and will be presented at international scientific meetings.

Trial Registration Number: NCT05087290.