Surgery is conducted annually in millions of patients with high blood pressure yet we know relatively little about how we should conduct post-surgical care of these individuals. Previous research shows that high blood pressure is associated with increased risk of death and heart-related complications in general, however there is very little information about how this affects patients undergoing surgery. The purpose of this study is therefore to define whether there are certain blood pressure values (such as very high values) that are associated with increased complications following surgery such as heart attacks or strokes and to determine whether blood pressure variability affects such risks. We will also seek to determine if certain drugs used for blood pressure management offer benefits over others. Understanding the impact of preoperative blood pressure thresholds could also help identify patient subgroups (for example those with high or low preoperative blood pressure or increased blood pressure variability) that need to be treated differently prior to surgery to prevent complications.
There are limited data to inform the perioperative care of patients with hypertension, including identification of blood pressure values that are associated with increased perioperative cardiovascular mortality and morbidity or optimal preoperative medication for reducing such risks. Therefore the aim of the study is to identify the effect of preoperative blood pressure and blood pressure variability (with and without antihypertensive medication prior to surgery) on the risks of postoperative cardiovascular morbidity (acute coronary syndrome (ACS) and stroke). We will use the CPRD-linked HES data to establish a cohort of adults aged ? 18 years with and without hypertension who underwent an elective non-cardiac surgery between 1st April 1997 and March 31st 2017. All patients will then be followed up from the date of surgery until they develop the outcome (ACS or stroke) or leave the study. We will extract data on preoperative blood pressure measurements and antihypertensive medications from primary care. Based on a cohort design we will calculate crude and adjusted hazard ratios using survival analysis. Adjustment will be carried out for age, gender, socioeconomic status, body mass index, smoking, pre-existing comorbidity and use of antihypertensive medications.
David Humes - Chief Investigator - University of Nottingham
Lu Ban - Corresponding Applicant - University of Nottingham
Puja Myles - Collaborator - CPRD
Rob Sanders - Collaborator - University Of Wisconsin Madison
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation