Optimising BP measurement and treatment before elective surgery: taking the pressure off

Br J Cardiol 2017;24:11–12doi:10.5837/bjc.2017.005 Leave a comment
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Hypertension remains a significant burden on mortality and morbidity, contributing to increasing costs to healthcare provision globally. There is detailed evidence-based guidance on the diagnosis and treatment of hypertension in the community, however, during the peri-operative period for elective surgery, consideration of an elevated blood pressure remains a conundrum. This is a consequence of paucity of evidence, particularly around specific blood pressure cut-offs deemed to be clinically safe. Postponement of planned surgical procedures due to elevated blood pressure is a common reason to cancel necessary surgery. A sprint audit of 11 West London Hospitals with national audit data indicated that the number of cancellations was 1–3%, equating to approximately 100 cancellations per day in the UK.1 This suggests that approximately 39,730 patients per year may have had a cancellation of a surgical procedure owing to a finding of pre-operative hypertension.2 The Association of Anaesthetists of Great Britain and Ireland (AAGBI) together with the British Hypertension Society (BHS) recognise the need for a nationally agreed policy statement on how to deal with raised blood pressure in the pre-operative period and have jointly published guidelines titled: “The measurement of adult blood pressure and management of hypertension before elective surgery” in the journal Anaesthesia.2

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This publication in the British Journal of Cardiology is part of the need for coordinated publications to ensure that cardiologists are aware of the current consensus. The recommendations are limited to a specific scope – the period prior to planned surgery. Blood pressures that may cause an immediate risk to health are specified, rather than those that may cause risk over the long term. The best method of taking accurate blood pressure measurements is also examined. For the cardiologist who may be contacted to provide advice and management options for hospitalised patients with elevated blood pressure during the pre-operative period, this guideline recommends that patients with stage 1 and stage 2 hypertension may proceed to surgery.

There is no evidence that peri-operative blood pressure reduction affects rates of cardiovascular events beyond that expected in primary care. Specifically, there is no current evidence of harm, peri-operatively, in people with stage 1 or 2 hypertension, i.e. people with a blood pressure less than 160 mmHg systolic or 100 mmHg diastolic.5 The disparity between blood pressure care is based on good evidence that the rates of cardiovascular morbidity, in particular stroke, are reduced over years and decades.3 Consideration of the ‘white-coat’ effect in the pre-operative period in pre-op clinics and immediately prior to surgery is critical. These high blood pressure measurements have contributed to cancellations of surgery, even though white-coat measurements may not be representative of the patient’s usual blood pressure or of their risk of end-organ damage due to hypertension.

What cardiologists should be doing

When consulted for advice on managing an isolated elevated blood pressure, obtained from a patient admitted for elective surgery, the advice should be that patients with hypertension do not need to have their elective procedure delayed as long as the systolic and diastolic blood pressures are less than 180/110 mmHg, respectively. For patients using antihypertensive agents longitudinally, peri-operative medical therapy should be continued. For patients with a new diagnosis of hypertension pre-operatively, the European Society of Cardiology (ESC) guidelines recommend screening for end-organ damage and cardiovascular risk factors (Class I, Level C). For specific agents, particularly pertaining to long-term beta-blocker use, according to the American College of Cardiology (ACC)/American Heart Association (AHA) guidelines, continuation of pre-existing beta-blockade is the only class I indication for routine pre-operative use of these drugs.4 There are fewer data to describe whether short-term (one to two days) peri-operative use of beta blockers, followed by rapid discontinuation, is harmful. The Peri-Operative ISchemic Evaluation (POISE) trial demonstrated that although peri-operative beta-blockade reduced the risk of peri-operative myocardial infarctions, significantly higher rates of stroke and mortality were observed.6 Similar findings were confirmed following a systematic review of 12,381 participants from 17 studies, for the 2014 ACC/AHA guideline.7 However, the POISE trial protocol has been criticised (high-dose metoprolol administered within 2–4 hours of surgery in beta-blocker-naïve patients, some of whom had cardiac failure) and is likely to have contributed to these negative outcomes. A meta-analysis published just after POISE found in favour of peri-operative beta-blockade secondary to a reduction in non-fatal myocardial infarction (MI).8 Continuation of angiotensin-converting enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs) peri-operatively is also reasonable. If ACE inhibitors or ARBs are withheld before surgery, it is reasonable to restart as soon as clinically feasible postoperatively. Similarly, continuation of diuretics for hypertension should be continued to the day of surgery and resumed orally when possible.9 The possibility of electrolyte disturbance should be considered in any patient receiving diuretics. Patients with stage 3 hypertension (systolic blood pressure greater than or equal to 180 mmHg) should have their blood pressure controlled before surgery. There is no clear evidence favouring one mode of antihypertensive therapy over another in patients undergoing non-cardiac surgery.9

Recommendations (and suggestions for care)

The AAGBI/BHS recommendations are in line with those by the ACC/AHA and the European Society of Hypertension (ESH)/ESC, which considers uncontrolled systemic hypertension a minor clinical predictor of increased peri-operative cardiovascular risk.10 Indeed, stratifying the overall cardiovascular risk of the surgical patient may be more important.

  1. GPs should refer patients for elective surgery with mean blood pressures in primary care in the past 12 months less than 160 mmHg systolic and less than 100 mmHg diastolic.
  2. Secondary care should accept referrals that document blood pressures below 160 mmHg systolic and below 100 mmHg diastolic in the past 12 months.
  3. Pre-operative assessment clinics need not measure the blood pressure of patients being prepared for elective surgery whose systolic and diastolic blood pressures are documented below 160/100 mmHg in the referral letter from primary care.
  4. GPs should refer hypertensive patients for elective surgery after the blood pressure readings are less than 160 mmHg systolic and less than 100 mmHg diastolic. Patients may be referred for elective surgery if they remain hypertensive despite optimal antihypertensive treatment or if they decline antihypertensive treatment.
  5. Surgeons should ask GPs to supply primary care blood pressure readings from the last 12 months if they are undocumented in the referral letter.
  6. Pre-operative assessment staff should measure the blood pressure of patients who attend clinic without evidence of normotension being documented by primary care in the preceding 12 months.
  7. Elective surgery should proceed for patients who attend the pre-operative assessment clinic without documentation of normotension in primary care if their blood pressure is less than 180 mmHg systolic and 110 mmHg diastolic when measured in clinic.

A practical way forward

Mindful of the increasing pressures on primary care and the increased GP workload, these recommendations are meant to be practical rather than just another set of guidelines. Most importantly, we hope hospital departments might recognise that the presence of stage 1 and 2 hypertension has little impact on early outcomes after elective surgery, and determine care based on the measurements taken in primary care.

Conflict of interest

None declared.

References

1. Soni S, Chaggar R, Saini R et al. Unsafe for surgery: a regional survey investigating the variation of pre-operative hypertension management across anaesthetic departments. Anaesthesia 2015;70(Suppl 2):42. https://doi.org/10.1111/anae.12962

2. Hartle A, McCormack T, Carlisle J et al. The measurement of adult blood pressure and management of hypertension before elective surgery: Joint Guidelines from the Association of Anaesthetists of Great Britain and Ireland and the British Hypertension Society. Anaesthesia 2016;71:326–37. https://doi.org/10.1111/anae.13348

3. Ettehad D, Emdin CA, Kiran A et al. Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis. Lancet 2015;387:957–67. https://doi.org/10.1016/S0140-6736(15)01225-8

4. Hanada S, Kawakami H, Goto T et al. Hypertension and anesthesia. Curr Opin Anaesthesiol 2006;19:315–19. https://doi.org/10.1097/01.aco.0000192811.56161.23

5. Fleisher LA, Beckman JA, Brown KA et al. 2009 ACCF/AHA focused update on perioperative beta blockade incorporated into the ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Circulation 2009;120:e169–e276. https://doi.org/10.1161/CIRCULATIONAHA.109.192690

6. POISE Study Group. Effects of extended-release metoprolol succinate in patients undergoing non-cardiac surgery (POISE trial): a randomised controlled trial. Lancet 2008;371:1839–47. https://doi.org/10.1016/S0140-6736(08)60601-7

7. Wijeysundera DN, Duncan D, Nkonde-Price C et al. Perioperative beta blockade in noncardiac surgery: a systematic review for the 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2014;130:2246–64. https://doi.org/10.1161/CIR.0000000000000104

8. Bangalore S, Wetterslev J, Pranesh S et al. Perioperative beta blockers in patients having non-cardiac surgery: a meta-analysis. Lancet 2008;372:1962–76. https://doi.org/10.1016/S0140-6736(08)61560-3

9. Kristensen SD, Knuuti J. 2014 ESC/ESA guidelines on non-cardiac surgery: cardiovascular assessment and management. Eur Heart J 2014;35:2383–431. https://doi.org/10.1093/eurheartj/ehu285

10. Mancia G, Fagard R, Narkiewicz K et al. 2013 ESH/ESC guidelines for the management of arterial hypertension: the Task Force for the management of arterial hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC). J Hypertens 2013;31:1281–357. https://doi.org/10.1097/01.hjh.0000431740.32696.cc

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