Adult hypertension referral pathway and therapeutic management: British and Irish Hypertension Society position statement

In the UK, most adults with hypertension are managed in Primary Care. Referrals to Secondary Care Hypertension Specialists are targeted to patients in whom further investigations are likely to change management decisions. In this position statement the British and Irish Hypertension Society provide clinicians with a framework for referring patients to Hypertension Specialists. Additional therapeutic advice is provided to optimise patient management whilst awaiting specialist review. Our aim is to ensure that referral criteria to Hypertension Specialists are consistent across the UK and Ireland to ensure equitable access for all patients.


INTRODUCTION
In the UK, most adults with hypertension are managed in Primary Care.National and international guidelines advise that adult referrals to Secondary Care Hypertension Specialists are targeted at patients in whom further investigations are likely to change management decisions [1][2][3][4][5][6].Referrals are recommended when patients have raised blood pressure with life threatening target-organ damage (i.e.emergency/same day referrals); or when patients have, for example, suspected secondary hypertension, resistant hypertension, or complex polypharmacy (i.e.routine referrals) [1][2][3][4][5][6].
In this statement, the British and Irish Hypertension Society (BIHS) summarise their recommendations for adult emergency and routine referrals to Secondary Care Hypertension Specialists and highlight where this advice is supported by the National Institute for Health and Care Excellence (NICE) and/or International Societies (Tables 1 and 2) [1][2][3][4][5][6].Table 3 summarises the ideal information to accompany referrals to facilitate communication between Primary and Secondary Care services.Where there are long waiting times to access routine Secondary Care hypertension services, the BIHS offer additional therapeutic advice to optimise patient management whilst awaiting specialist review (Fig. 1).Finally, the challenges facing referrers in identifying a Hypertension Specialist in the UK are discussed.

ADULT REFERRAL CRITERIA TO A SECONDARY CARE HYPERTENSION SPECIALIST
The clinical situations where the BIHS recommends emergency/ same day referrals are outlined in Table 1.
The clinical situations where the BIHS recommends routine referrals are outlined in Table 2.
Prior to making routine referrals, clinicians should have: 1. Confirmed hypertension is present by either Ambulatory Blood Pressure Monitoring (ABPM) or Home Blood Pressure Monitoring (HBPM).AND if applicable, 2. Followed NICE guidelines NG136 on hypertension management [1], Fig. 1.

INFORMATION TO SHARE WITH HYPERTENSION SPECIALISTS
To facilitate communication between referrers and Hypertension Specialists, the BIHS recommends that, where possible, the information in Table 3 is included with the referral.This avoids patients undergoing repeated testing unnecessarily, maximises the efficient use of resources and enables patients to start new, or modified, treatment regimens as soon as possible.

MANAGEMENT ADVICE FOR ROUTINE REFERRALS AWAITING HYPERTENSION SPECIALIST REVIEW
The BIHS acknowledges that current waiting times for routine NHS referrals may be considerable.To optimise hypertension treatment whilst patients await specialist review, clinicians may wish to consider the following steps: • For newly diagnosed patients in whom secondary causes are suspected, or aged <40 years at diagnosis, or post-partum, a non renin-angiotensin-aldosterone system interfering drug is preferred (e.g.amlodipine or equivalent) as a temporary treatment while awaiting specialist review.This will facilitate interpretation of screening tests for the secondary causes of hypertension.Definitive long-term therapy should follow the guidance in Fig. 1.

•
For those with established and uncontrolled hypertension, having tried multiple drug therapies, additional therapeutic options are summarised in Fig. 1.The choice of exemplar drugs within each class was based on the totality of evidence for each drug in reducing morbidity and mortality combined with duration of action.Long acting drugs are strongly preferred to minimise the impact of a missed dose and reduce blood pressure variability.
• Clinicians may also find patients are willing to revisit lifestyle modifications, including optimising weight, salt and alcohol intake and review their medication concordance whilst awaiting specialist advice.Re-assessing white coat hypertension by ABPM or HBPM can also be helpful [8].NICE [1], ESC/ESH [4,5], ISH [6] Hypertension in pregnancy (requires a multi-disciplinary team approach) AND women who remain hypertensive postpartum.
NICE [  specialist registration for hypertension doctors and the only medical training curriculum that includes a specific module in hypertension is Clinical and Therapeutics.The BIHS is currently working on a system for accreditation and recognition of specialist hypertension services in the UK.In the interim, referrers can check if their local Hypertension Specialist is a member of the British and Irish Hypertension Society (Email: bihs@in-conference.org.uk),holds a European Hypertension Specialist certificate (https://www.eshonline.org/communities/hypertension-specialist/directory-of-specialists/) or works at a European Hypertension Centre of Excellence (https://www.eshonline.org/communities/excellence-centres/).
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material.If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.To view a copy of this licence, visit http:// creativecommons.org/licenses/by/4.0/.

Table 1 .
OF A HYPERTENSION SPECIALIST It is important to refer patients to Hypertension Specialists who have appropriate training, experience and interest in hypertension management and who have access to specialist facilities to conduct relevant investigations.In the UK, there is currently no BIHS criteria for emergency/same day referrals.
[1,3]tensive crisis.Life threatening target-organ damage even in the context of mild or severe hypertension, including, but not limited to, acute aortic dissection, acute kidney injury, acute myocardial ischaemia, acute heart failure, acute stroke or phaeochromocytoma.NICE[1], ESC/ESH[4,5]Pre-eclampsia and severe hypertension in pregnancy.Requires a multi-disciplinary team approach.NICE[1,3], ESC/ESH [4, 5] NICE National Institute for Health and Care Excellence, ESC European Society of Cardiology, ESH European Society of Hypertension.
Suspected secondary hypertension, including, but not limited to hyperaldosteronism (e.g.hypokalaemia); phaeochromocytoma (e.g.palpitations, headache, flushing, family history, history of neurofibromatosis); druginduced hypertension (e.g.concomitant prescription of combined oral contraceptive pill or implant, hormone substitutes, steroids, NSAIDs, VEGF inhibitors, tyrosine kinase inhibitors (TKIs), tricyclic antidepressants, SSNRIs, dexamphetamine, methylphenidate).Please note these are common examples but do not represent an exhaustive list of the secondary causes of hypertension.
ESC European Society of Cardiology, ESH European Society of Hypertension, ISH International Society of Hypertension, NICE National Institute for Health and Care Excellence, NSAIDs Nonsteroidal Anti-inflammatory Drugs, SSNRI selective serotonin noradrenaline reuptake inhibitor, VEGF vascular endothelial growth factor.

Table 3 .
Information to share with hypertension specialists.Previous intolerance to specific antihypertensive drugs with reasons • Relevant medical history and family history • Duration of hypertension / age at diagnosis • Blood and urine test results • Ambulatory and/or home blood pressure monitoring results • ECG and/or echocardiography results • Imaging reports (e.g.CXR, renal ultrasound, CT or MRI) ECG electrocardiogram, CXR chest x-ray, CT computed tomography, MRI magnetic resonance imaging.