Hypertension (High Blood Pressure)

Hypertension (i.e., high blood pressure), is one of the most common chronic cardiovascular conditions in the U.S. and was the primary cause of almost 25,000 deaths nationally in 2019.¹ In many cases, unless it is measured, people can have hypertension but may be unaware of it, as it can be a relatively symptom-free disease.² Hypertension is a major risk factor for cardiovascular disease and stroke.³ Data from the National Health and Nutrition Examination Survey (NHANES) 2013 to 2016 indicate that 35.3% of U.S. adults with hypertension are unaware that they have it.³ Using current blood pressure thresholds from the 2017 American College of Cardiology/American Heart Association (ACC/AHA) guidelines,³ the prevalence of hypertension among U.S. adults for the years 2011 to 2014 was 45.6% (95% confidence interval [CI] 43.6 to 47.6%) compared with 31.9% (95% CI 30.1 to 33.7%), using the older thresholds from the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VII).³

Blood pressure is the force of blood pushing against blood vessel walls and is measured in millimeters of mercury (mm Hg).^{4, 5} Within the circulatory system, the blood pressure is dependent on a number of factors, including cardiac output, blood volume, heart rate, venous return, peripheral vascular resistance, and large artery elasticity.^{6, 7} Blood pressure is represented as two numbers, the upper number or systolic blood pressure, measures the pressure of blood when the heart beats (after the ventricles contract).^{4, 7} The second, or bottom number, is the diastolic blood pressure; this is the measured pressure of blood on the circulatory system when the heart rests between beats (following closure of the aortic valve).^{4, 5} Untreated or uncontrolled hypertension, which is defined as higher than normal blood pressure that stays high consistently, can result in many systemic consequences, including stroke or heart attack or other serious end-organ damage (e.g., renal failure, vision changes/blindness).⁴ Sustained hypertension can also lead to left-ventricular hypertrophy, as the cardiac muscle attempts to compensate for the elevated pressure.⁸

A 2001 study⁹ examining the prevalence of hypertension in a dental university clinic cohort of more than 3,500 individuals found that 16.6% of the people were hypertensive (defined in the study as clinic-measured systolic reading of greater than 140 mm Hg or a diastolic reading of greater than 90 mm Hg) at the time of screening.  Of this group, 32.2% reported having been told by a physician that they had hypertension.  However, 27% had no previous diagnosis of hypertension.  This suggests that measuring blood pressure in the dental setting has utility in identifying people with undiagnosed hypertension, as well as people whose hypertension may not be well controlled.

Hypertension can be either acute or chronic.⁵ Acute hypertension can result from such stimuli as physical exertion, anxiety, or stress, and generally normalizes once the stimulus ceases.⁵  Chronic hypertension is blood pressure that remains consistently higher than normal.⁵  “White-coat” hypertension refers to blood pressure that is elevated when measured in a health care setting, but otherwise normal (e.g., when measured at home);¹⁰ the “white-coat effect” is larger in older populations.³ A multicenter, observational study of blood pressure screening in a Swedish dental healthcare setting evaluated over 2,000 individuals and estimated the prevalence of white coat hypertension in this population to be 17.7%.¹⁰

Diagnosis of hypertension is generally based on an average of two or more elevated measurement readings obtained on two or more occasions.^{11, 12}  According to the 2017 ACC/AHA blood pressure categories^{3, 11, 12} (Table 1), hypertension is defined as a systolic pressure of 130 mmHg or greater or a diastolic blood pressure of 80 mmHg or greater.^{3, 11, 12}  A blood pressure target of less than 130/80 mmHg is recommended for people with markers of increased risk (e.g., persistently elevated lipids, metabolic syndrome, chronic kidney disease) and the 2017 ACC/AHA guideline considers it a reasonable target even for those without markers of increased risk.^11-13  Threshold blood pressure definitions for hypertension changed following publication of more recent data from trials like the Systolic Blood Pressure Intervention trial (SPRINT), showing that more intensive blood pressure control resulted in lower rates of fatal and nonfatal major cardiovascular events and death from any cause.^{14, 15}

Table 1. 2017 ACC/AHA Blood Pressure Categories^{4, 11, 12}

Although the exact cause of hypertension may be unclear, factors that contribute to its development include obesity, smoking, lack of physical activity, diet (e.g., excess sodium or alcohol intake), age, familial history/genetics, pain, medications (e.g., stimulants, decongestants, immunosuppressants, corticosteroids, oral contraceptives) and certain diseases (e.g., chronic kidney disease, thyroid or adrenal disorders, sleep apnea).^{2, 5, 16} Hypertensive disease not associated with a specific cause/disease is classified as “essential” or primary hypertension, while hypertension that has a specific identified cause (e.g., hyperthyroidism, vascular diseases, adrenal medullary dysfunction) is classified as secondary hypertension.¹⁷Generally, if the specific cause of the secondary hypertension is corrected, the blood pressure will return to normal.^{16, 17}

Essential hypertension accounts for 90% to 95% of all cases of high blood pressure in the U.S.^{2, 16, 17}Pathophysiologic mechanisms that contribute to essential hypertension are salt/volume overload, activation of the renin angiotensin-aldosterone system, and/or activation of the sympathetic nervous system.¹⁷ It is these pathophysiologic mechanisms that specific pharmacologic (e.g., antihypertensive medications) and nonpharmacologic (e.g., behavioral changes, low-sodium diet) treatments aim to modify.¹⁷

Blood pressure can be measured using a manual or automated device. The manual method (auscultatory method) involves use of a mercury/aneroid sphygmomanometer consisting of an inflatable cuff, pressure display, and inflation bulb, plus a stethoscope.^{2, 5, 17} Follow the manufacturer’s directions. In general, manually checking a person’s blood pressure involves the following series of steps: locate the radial pulse by gently placing the index and middle fingers on the thumb side of the patient’s wrist when the palm of the hand is facing upwards.⁵ The blood pressure cuff is placed snugly around the upper arm, just above the elbow, and the cuff bladder i8flated using the bulb, noting the pressure point at which the radial pulse can no longer be felt.⁵ Deflate the cuff, place the stethoscope over the brachial artery, just below the cuff, then reinflate the cuff to a pressure 30 mm Hg higher than the point at which the radial pulse could no longer be felt.⁵ As the cuff is then slowly deflated (i.e., a bladder deflation rate of 2 to 3 mm Hg per second),¹⁶ the systolic pressure is the pressure measurement denoting when the brachial artery pulse is first heard.¹⁸  The diastolic pressure is the pressure measurement at which the brachial artery pulse is no longer heard.¹⁸ The cuff can then be fully deflated.

Automated (i.e., oscillometric) devices for blood pressure measurement come in various types, measuring blood pressure in the upper arm, wrist, or a finger, and generally have a digital readout/display.^{2, 17} The8AHA recommends that individuals use an automatic, cuff-style, bicep (upper-arm) monitor for monitoring blood pressure at home, as wrist and finger monitors “yield less reliable readings.”¹⁹

When obtaining a blood pressure measurement in the dental office, it is recommended that the person being evaluated sit quietly for 5 minutes in a chair with their feet flat on the floor and their arm supported at the level of their heart.^{2, 17}  There are various cuff sizes available (e.g., small, medium, large) depending upon the age and size of the patient.⁵ Ideally, the length and width of the cuff bladder should be 80% and 40%, respectively, of the bare upper arm.^{2, 7, 18}

Nonpharmacologic.  Initial strategies for people with high blood pressure include modifying diet, engaging in regular moderate exercise, maintaining healthy weight, and limiting alcohol intake.^{7, 11, 12, 20}The Dietary Approaches to Stop Hypertension, or “DASH” plan has been promoted by the AHA and the Centers for Disease Control and Prevention as an evidence-based approach to help manage hypertension.²⁰ DASH consists of increased intake of fruits and vegetables, as well as low-fat dairy products, and restriction of sodium intake to less than 2.4 g per day.^{7, 20}  Although there is some evidence that nonpharmacologic intervention(s) can have a favorable effect on blood pressure, most people will require antihypertensive medication(s) to bring the blood pressure into a more normal range.⁷

Pharmacologic. It is recommended that people with newly diagnosed hypertension be prescribed a single drug (monotherapy) as initial therapy.¹⁴  If blood pressure remains uncontrolled with single-agent therapy, the addition of another drug with a different mechanism of action is generally more effective than increasing the dose of the first drug; both drugs then can be used at lower, better tolerated doses.¹⁴ However, if at baseline, blood pressure is more than 20/10 mmHg above goal, many experts would recommend beginning therapy with two drugs.¹⁴ Some blood pressure medications are formulated as oral fixed-dose combinations, for example, beta-blockers plus diuretics (e.g., metoprolol plus hydrochlorothiazide).^{14, 21}  These are not generally used as first-line therapy, but in people who require two or more drugs from different therapeutic classes to control their blood pressure. A listing of antihypertensive medication classes available in the U.S. can be seen in Table 2.

Table 2. Antihypertensive Medication Classes Available in the U.S.^{2, 14, 21, 22}

^{*not intended to be an inclusive list}

General Patient Considerations

One approach to obtaining a medical history is to evaluate vital signs, including heart rate (pulse) and blood pressure, at every dental visit.²³ Dental patients may experience acute high blood pressure related to a physiologic response to pain or anxiety.¹⁶ This is one reason that gathering information on health status and current medications in all dental patients, including those with hypertension, can be valuable.¹⁶  When interviewed for a medication history, people may not know which of their medications are for hypertension; also, patients whose hypertension is well-controlled may not consider themselves as having high blood pressure, when asked.¹⁶

Symptoms of hypertensive crisis/emergency may include headache, vision changes, shortness of breath, or chest pain; immediate referral to emergency care may be warranted to prevent adverse sequelae such as stroke or end-organ damage.^{7, 16, 17} Proposed blood pressure thresholds and management algorithms from the ADA Practical Guide to Patients with Medical Conditions⁸ for elective and emergency dental care in adult patients (i.e., older than 18 years) with hypertension are listed in Table 3.⁸

Table 3.  Outpatient Dental Care Recommendations for Adult Patients with Hypertension⁸

*Patients with systolic pressure >180 mmHg and/or diastolic pressure >100 mmHg should be referred to their physician as soon as possible or sent for urgent medical evaluation, if symptomatic.  Comorbidities may change these broad recommendations.

A recent paper in JADA by Yarows et al.²⁴suggests a dental care management strategy for patients with hypertension who are under a physician’s care based on 2016 anesthesiology consensus guidelines from the U.K., using the patient’s functional status and past blood pressure measurements to determine whether to proceed with dental care.  The authors cite lack of published study evidence or professionally accepted criteria to indicate a specific blood pressure elevation at which to defer or postpone oral health care.²⁴  The 2017 ACC/AHA High Blood Pressure Clinical Practice Guidelines recommend that deferring surgery may be considered in persons with hypertension and planned elective major surgery who have a systolic pressure of 180 mm Hg or higher or diastolic pressure of 110 mm Hg or higher.^{11, 12}

Orthostatic Hypotension.  Some people with hypertension, especially older adults, those with diabetes mellitus, or autonomic dysfunction, may also experience orthostatic hypotension, which is an acute drop in blood pressure when attempting to stand after having been in a recumbent position for a period of time, e.g., in laying in a dental chair.¹⁶ Orthostatic hypotension can also be an adverse effect of some blood pressure medications.¹⁶ In many cases, having a person gradually assume a more vertical posture after dental treatment helps to prevent orthostatic hypotension.¹⁶

Dental Treatment Considerations for Adult Patients with Hypertension

Vasoconstrictors, such as epinephrine, are often combined with local anesthetics to reduce the rate of systemic absorption of the anesthetic from the injection site. This both helps to reduce systemic anesthetic toxicity as well as to increase anesthetic dwell time at the site of injection, improving anesthetic effect following infiltration or nerve block.^{2, 25} Vasoconstrictors may also reduce bleeding at the operative site.²² A 2002 systematic review by Bader et al.²⁶specifically sought evidence on the cardiovascular effects of epinephrine (either in local anesthetics or in gingival retraction cord) in hypertensive dental patients. Six papers on local anesthetic combinations were included in the review; no studies concerning retraction cords met selection criteria. Although the review concluded that the risk of adverse events in people with hypertension (controlled or uncontrolled) was low following injection of local anesthetics containing epinephrine, the authors acknowledged that the evidence was limited in both quantity and quality.²⁶

Although vasoconstrictors are rarely contraindicated,^{7, 25}the potential for cardiovascular stimulation (e.g., increased heart rate, increased blood pressure) following inadvertent intravascular injection may cause dental practitioners to reduce or avoid vasoconstrictor-containing formulations in individuals with cardiovascular compromise.²⁵ Using anesthetic formulations with no or limited amounts of vasoconstrictors, using slow injection technique, and aspirating carefully and repeatedly are common recommendations to prevent rapid systemic absorption of epinephrine and other vasoconstrictors.^{7, 25} If a vasoconstrictor is required for dental treatment and there is a medical history suggesting a need for caution, a common recommendation is to limit the epinephrine dose to 0.04 mg in adults.^{22, 25} This is equivalent to the use of:^{22, 25}

One cartridge of anesthetic containing 1:50,000 epinephrine;
Two cartridges of anesthetic containing 1:100,000 epinephrine; or
Four cartridges of anesthetic containing 1:200,000 epinephrine

Due to the higher concentration of epinephrine in epinephrine-impregnated gingival retraction cords,¹⁷their use has been discouraged in people with uncontrolled hypertension.^{2, 7}

Most classes of antihypertensive mediations can cause dry mouth (xerostomia).^{2, 16, 17} In addition, in 2% to 83% of patients being treated with a calcium-channel blocker, gingival hyperplasia has been reported;^{2, 7, 17} the calcium channel blocker most commonly associated with this reaction is nifedipine.^{2, 7} Treatment of medication-related adverse oral effects may be as simple as addressing the symptom (e.g., encouraging frequent sips of water in people with medication-related dry mouth) or may require working with the person’s medical doctor to change treatment.¹⁷ For example, gingival hyperplasia induced by calcium-channel blocker therapy may be treated surgically to temporarily relieve overgrowth, pain, and bleeding, but recurrence is likely unless the causative medication is discontinued.^{7, 16}  A listing of certain antihypertensive medications and possible dental/orofacial adverse effects can be seen in Table 4.

Table 4. Antihypertensive Medication Categories and Potential Dental/Orofacial Adverse Effects^{2, 17}

1. Heron M. Deaths: Final Data for 2019 Hyattsville, MD: U.S. Department of Health and Human Services. July 26, 2021. https://www.cdc.gov/nchs/data/nvsr/nvsr70/nvsr70-09-508.pdf. Accessed October 18, 2022.
2. Southerland JH, Gill DG, Gangula PR, et al. Dental management in patients with hypertension: challenges and solutions. Clin Cosmet Investig Dent 2016;8:111-20.
3. Benjamin EJ, Muntner P, Alonso A, et al. Heart Disease and Stroke Statistics-2019 Update: A Report From the American Heart Association. Circulation 2019;139(10):e56-e528.
4. American Heart Association. What is High Blood Pressure? 2021. https://www.heart.org/-/media/files/health-topics/answers-by-heart/what-is-high-blood-pressure.pdf. Accessed November 1, 2022.
5. Alexis O. Providing best practice in manual blood pressure measurement. Br J Nurs 2009;18(7):410-5.
6. Marieb EN, Hoehn K. Human Anatomy & Physiology. Hoboken, NJ: Pearson Education, Inc.; 2019.
7. Bavitz JB. Dental management of patients with hypertension. Dent Clin North Am 2006;50(4):547-62, vi.
8. Hupp WS. Cardiovascular Diseases. In: Patton LL, Glick M, editors. The ADA Practical Guide to Patients with Medical Conditions. 2nd ed. Hoboken, NJ: John Wiley & Sons, Inc.; 2016.
9. Gordy FM, Le Jeune RC, Copeland LB. The prevalence of hypertension in a dental school patient population. Quintessence Int 2001;32(9):691-5.
10. Andersson H, Hedström L, Bergh H. White-coat hypertension detected during opportunistic blood pressure screening in a dental healthcare setting. Scand J Prim Health Care 2021;39(3):348-54.
11. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation 2018;138(17):e426-e83.
12. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation 2018;138(17):e484-e594.
13. In brief: New hypertension guidelines. Med Lett Drugs Ther 2017;59(1535):202.
14. Drugs for hypertension. Med Lett Drugs Ther 2017;59(1516):41-48.
15. Sprint Research Group, Wright JT, Jr., Williamson JD, et al. A Randomized Trial of Intensive versus Standard Blood-Pressure Control. N Engl J Med 2015;373(22):2103-16.
16. Yagiela JA, Haymore TL. Management of the hypertensive dental patient. J Calif Dent Assoc 2007;35(1):51-9.
17. Hogan J, Radhakrishnan J. The assessment and importance of hypertension in the dental setting. Dent Clin North Am 2012;56(4):731-45.
18. Weinberg MA, Segelnick SL, Sapanaro DM. How to accurately measure blood pressure. Gen Dent 2019;67(5):58-61.
19. American Heart Association. Monitoring Your Blood Pressure at Home. https://www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings/monitoring-your-blood-pressure-at-home. Accessed November 1, 2022.
20. National Heart Lung and Blood Institute. In Brief: Your Guide to Lowering Your Blood Pressure with DASH (NIH Publication No. 06-5834). National Institutes of Health (2006; rev. 2015). https://www.nhlbi.nih.gov/education/dash/living-with-dash. Accessed November 1, 2022.
21. American Heart Association. Types of Blood Pressure Medications. https://www.heart.org/en/health-topics/high-blood-pressure/changes-you-can-make-to-manage-high-blood-pressure/types-of-blood-pressure-medications#.V__EZ_krIdU. Accessed November 1, 2022.
22. Hardeman JH. Hypertension and the Dental Patient. Dent Today 2017;36(1):126-8.
23. Patton LL. Medical History, Physical Evaluation, and Risk Assessment. In: Patton LL, Glick M, editors. The ADA Practical Guide to Patients with Medical Conditions. 2nd ed. Hoboken, NJ: John Wiley & Sons, Inc.; 2016.
24. Yarows SA, Vornovitsky O, Eber RM, Bisognano JD, Basile J. Canceling dental procedures due to elevated blood pressure: Is it appropriate? J Am Dent Assoc 2020:S0002-8177(19)30906-7.
25. Moore PA, Hersh EV. Chapter 7: Local Anesthetics for Dentistry. ADA Dental Drug Handbook: A Quick Reference. Chicago, IL: American Dental Association; 2019.
26. Bader JD, Bonito AJ, Shugars DA. A systematic review of cardiovascular effects of epinephrine on hypertensive dental patients. Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 2002;93(6):647-53.

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