Resistant Hypertension- Cardiac Microvascular Perfusion and Mechanics
Research type
Research Study
Full title
Resistant Hypertension – Pathological Insights from Cardiac Microvascular Perfusion and Mechanics
IRAS ID
274867
Contact name
Gregory Lip
Contact email
Sponsor organisation
University of Liverpool
Duration of Study in the UK
2 years, 1 months, 31 days
Research summary
Research Summary
People with poorly controlled high blood pressure (hypertension) are common in daily clinical practice and suffer a high rate of cardiovascular complications, including myocardial infarction, kidney failure, heart failure, stroke and death. Although significant improvement in awareness and hypertension drug therapies in several countries, including England, for a substantial proportion of patients, the blood pressure remains difficult to control and resistant to treatment despite the use of defined treatment regimens. According to the recent European Society of Cardiology/European Society of Hypertension guidelines for the management of arterial hypertension in adults population, the actual prevalence rate of resistant hypertension is up to 10% in treated hypertensive patients. Resistant hypertension is commonly defined as a failure to reduce office systolic and diastolic blood pressure readings to <140/90 mmHg in hypertensive patients despite the use of three or more antihypertensive medications including a diuretic (water tablet).
Patients with resistant hypertension have poor prognoses compared to non-resistant hypertensive patients. These patients are highly prone to the risk of target-organ damage and also at an increased risk of cardiovascular complications.
There is no published data on the inter-relationship between cardiac microvascular perfusion, cardiac mechanics, vascular and autonomic function in the resistant hypertensive population. In addition, the effect of intensified blood pressure management on these indices have not yet been fully investigated.
Therefore, the study will contribute novel data for a better understanding of the cardiac and vascular changes in patients with resistant hypertension. These pathophysiological mechanisms may explain the reason for the increased risk of cardiovascular complications in those patients. Therefore, the evaluation of cardiac microvascular perfusion, cardiac mechanics, vascular function may assist in clinical risk stratification and may have important prognostic and therapeutic implications. The study will also guide the potential of intensive pharmacological therapy to improve these measured indices in patients with resistant hypertension.Summary of Results
This is a prospective study in which 54 participants were recruited: 17 had resistant hypertension (RH) (mean age 60.5±12.4 years), 18 had controlled essential hypertension (CH) (mean age 57.7±12.2 years), and 19 had normal blood pressure (mean age 54.7±11.9 years). The study groups were matched for age, sex, ethnicity, weight, height, body surface area, waist-to-hip ratio, and heart rate. Patients with RH had higher body mass index than participants with normal blood pressure. There were no differences in terms of smoking status, prevalence of hypercholesterolemia and diabetes mellitus across the three groups. Both brachial and aortic blood pressure readings were markedly elevated in the RH group compared with CH and normal control groups. Duration of hypertension and utilisation of antihypertensive medications were similar between both hypertensive groups, except for diuretics (water tablets) and beta-blockers (medications that help slow down the heart rate), which were more prevalent in the RH group compared with the CH group (100% vs 28% and 47% vs 6%, respectively).
Patients with RH show evidence of greater cardiac remodelling and concomitant impairment of their left ventricular and left atrial cardiac mechanics when compared to participants with CH and normal blood pressure. Increased arterial stiffness and impaired endothelial function were also demonstrated in patients with RH compared with the other two groups. In addition, eight weeks of intensified blood pressure management in 16 RH patients lowers both brachial and aortic blood pressures and significantly improves cardiac mechanics, endothelial function, and arterial stiffness indices compared with baseline.
Cardiac and vascular changes may play an essential role in the progression of serious cardiovascular complications seen in RH patients. Therefore, early identification of subclinical cardiac abnormalities, endothelial dysfunction and arterial stiffness in patients with RH may have important prognostic and therapeutic implications.
REC name
South East Scotland REC 02
REC reference
20/SS/0086
Date of REC Opinion
23 Sep 2020
REC opinion
Further Information Favourable Opinion