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HYPERTENSION

HYPERTENSION. SOME PRELIMINARY DEFINITIONS. Blood pressure (BP) , sometimes referred to as arterial blood pressure, is the pressure exerted by circulating blood upon the walls of blood vessels , and is one of the principal vital signs .

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HYPERTENSION

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  1. HYPERTENSION

  2. SOME PRELIMINARY DEFINITIONS • Blood pressure (BP), sometimes referred to as arterial blood pressure, is thepressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. • When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. • During each heartbeat, blood pressure varies between a maximum (systolic) and a minimum (diastolic) pressure. The blood pressure in the circulation is principally due to the pumping action of the heart. •  Differences in mean blood pressure are responsible for blood flow from one location to another in the circulation. The rate of mean blood flow depends on the resistance to flow presented by the blood vessels. • Mean blood pressure decreases as the circulating blood moves away from the heart through arteries and capillaries due to viscous losses of energy. Mean blood pressure drops over the whole circulation, although most of the fall occurs along the small arteries and arterioles.

  3. SOME PRELIMINARY DEFINITIONS • Mean arterial pressure • The mean arterial pressure (MAP) is a term used in medicine to describe an average blood pressure in an individual. • The mean arterial pressure (MAP) is the average over a cardiac cycle and is determined by the cardiac output (CO), systemic vascular resistance (SVR), and central venous pressure (CVP) • CALCULATION : 1/3 (SBP + 2 DBP) • MAP is considered to be the perfusion pressureseen by organs in the body. • It is believed that a MAP that is greater than 60 mmHg is enough to sustain the organs of the average person. MAP is normally between 70 to 110 mmHg • If the MAP falls below this number for an appreciable time, vital organs will not get enough Oxygen perfusion, and will become ischemic.

  4. SOME PRELIMINARY DEFINITIONS • Normal blood pressure • < 120/80 mmHg • Pre hypertension • 120-129 or 80-89 mmHg • Stage 1 hypertension: • Clinic blood pressure (BP) is 140/90 mmHg or higher and • ABPM ( ambulatory blood pressure monitoring) or HBPM ( home bpm) average is 135/85 mmHg or higher. • Stage 2 hypertension: • Clinic BP 160/100 mmHg is or higher and • ABPM or HBPM daytime average is 150/95 mmHg or higher. • Severe hypertension: • Clinic systolic BP is 180 mmHg or higher or • Clinic diastolic BP is 110 mmHg or higher. • White-coat effect: • A discrepancy of more than 20/10 mmHg between clinic and average daytime ABPM or average HBPM blood pressure measurements at the time of diagnosis

  5. Aims of the talk • To diagnose hypertension • To treat hypertension • Why ? • Who ? • When ? • How ? • To what extend treat hypertension ?

  6. Second part : special issues in HPT • Primary HPT • Secundary HPT • HPT and Diabetes Mellitus • HPT in Pregnancy • Resistant HPT • New insights in HPT

  7. Case scenario 1 : Mary • Presentation • 38 year old, attending for routine appointment about her contraception, for which she uses a diaphragm. • Medical history • From her records you notice that Mary’s blood pressure has increased since her last check twelve months ago. She does not smoke, drinks 10-12 units of alcohol a week and has no notable medical history. • On examination • Mary’s first clinic blood pressure measurement is 158/94 mmHg. Her heart rate is 72 beats per minute and regular • You are considering a diagnosis of hypertension and therefore take another reading in Mary’s other arm. There is no notable difference between readings. • Next steps for diagnosis • Question 1.1 • What would you do next?

  8. Definitions • Normal blood pressure • < 120/80 mmHg • Pre hypertension • 120-129 or 80-89 mmHg • Stage 1 hypertension: • Clinic blood pressure (BP) is 140/90 mmHg or higher and • ABPM ( ambulatory blood pressure monitoring) or HBPM ( home bpm) average is 135/85 mmHg or higher. • Stage 2 hypertension: • Clinic BP 160/100 mmHg is or higher and • ABPM or HBPM daytime average is 150/95 mmHg or higher. • Severe hypertension: • Clinic systolic BP is 180 mmHg or higher or • Clinic diastolic BP is 110 mmHg or higher. • White-coat effect: • A discrepancy of more than 20/10 mmHg between clinic and average daytime ABPM or average HBPM blood pressure measurements at the time of diagnosis

  9. Case scenario 1 : Mary • Answer 1.1 • You would take Mary’s blood pressure a third time during the consultation. • Question 1.2 • The third reading is 149/93 mmHg. You suspect hypertension – what would you do next?

  10. Case scenario 1 : Mary • Answer 1.2 • Organise for Mary to receive ambulatory blood pressure monitoring (ABPM) through your GP practice. If you are responsible for setting up the monitoring device, you ensure that at least two measurements per hour are taken during Mary’s usual waking hours (for example, between 8 am and 10 pm). You would use the average value of at least 14 measurements taken during Mary’s usual waking hours to confirm a diagnosis of hypertension. • At the same time you would also carry out investigations for • target organ damage (such as left ventricular hypertrophy, chronic kidney disease and hypertensive retinopathy). • coexisting disorders • Move to the next slide for a lists of tests and further investigations

  11. How should the Blood Pressure be Measured? • In the Clinic • By the doctor? • By a nurse? • By an automated device? • Outside the Clinic • Home monitoring? • Ambulatory monitoring?

  12. The White Coat Effect in the Real World(Little et al, BMJ 2002; 325: 254) 173 hypertensive patients in 3 general practices in the UK Clinic (MD and RN), self-monitoring, and ABPM White coat effect estimated as difference between other measures of BP and daytime BP: ABPM Physician 19/11 mmHg Nurse 1 5/8 mmHg Nurse 2 5/6 mmHg Self-monitoring in clinic 10/13 mmHg Self-monitoring at home 5/6 mmHg

  13. 24 Hour Ambulatory Monitoring

  14. Prospective Studies Showing that Home BP Predicts CV Morbidity Better than Clinic BP • Author Year Population N Comments • Imai 1996 Population 1789 ABP & HBP predict, not CBP • Bobrie 2004 Treated 4939 HBP predicts, not CBP • Sega 2005 Population 2051 HBP predicts better than CBP Home monitoring should be recommended for all patients

  15. A Diagnosis of Hypertension based exclusively on Physician readings is no longer acceptable • Measurement error • Small number of readings • Effects of recent activities • Expense & Inconvenience • White coat effect

  16. Case scenario 1 : Mary • Answer 1.2 • Organise for Mary to receive ambulatory blood pressure monitoring (ABPM) through your GP practice. If you are responsible for setting up the monitoring device, you ensure that at least two measurements per hour are taken during Mary’s usual waking hours (for example, between 8 am and 10 pm). You would use the average value of at least 14 measurements taken during Mary’s usual waking hours to confirm a diagnosis of hypertension. • At the same time you would also carry out investigations for • target organ damage (such as left ventricular hypertrophy, chronic kidney disease and hypertensive retinopathy). • coexisting disorders • Move to the next slide for a lists of tests and further investigations

  17. Case scenario 1 : Mary • Answer 1.2 (continued) • test for the presence of protein in the urine by sending a urine sample for estimation of the albumin:creatinine ratio and test for haematuria using a reagent strip • take a blood sample to measure plasma glucose, electrolytes, creatinine, estimated glomerular filtration rate, serum total cholesterol and HDL cholesterol • examine the fundi for the presence of hypertensive retinopathy • arrange for a 12-lead electrocardiograph or an echocardiography to be performed

  18. JNC 7 Recommendations for Routine Work-up of Hypertensive Patients • Routine Tests • Electrocardiogram • Urinalysis • Blood glucose, and hematocrit • Serum potassium, creatinine, or the corresponding estimated GFR, and calcium • Lipid profile, after 9- to 12-hour fast, that includes high-density and low-density lipoprotein cholesterol, and triglycerides • Optional tests • Measurement of urinary albumin excretion or albumin/creatinine ratio • More extensive testing for identifiable causes is not generally indicated unless BP control is not achieved

  19. Case scenario 1 : Mary • Answer 1.2 • Organise for Mary to receive ambulatory blood pressure monitoring (ABPM) through your GP practice. If you are responsible for setting up the monitoring device, you ensure that at least two measurements per hour are taken during Mary’s usual waking hours (for example, between 8 am and 10 pm). You would use the average value of at least 14 measurements taken during Mary’s usual waking hours to confirm a diagnosis of hypertension. • At the same time you would also carry out investigations for • target organ damage (such as left ventricular hypertrophy, chronic kidney disease and hypertensive retinopathy). • coexisting disorders • Move to the next slide for a lists of tests and further investigations

  20. Overlap of Four Common Conditions Obesity SMOKING Hypertension Diabetes Sleep Disordered Breathing

  21. Case scenario 1 : Mary • Answer 1.2 (continued) • You would also carry out a formal assessment of cardiovascular risk (Mary’s clinic blood pressure must be used in the calculation of cardiovascular risk) using a cardiovascular risk assessment tool, in line with Identification and assessment of CVD risk in ‘Lipid modification’ (NICE clinical guideline 67). • Additionally, you would also ascertain information about lifestyle in areas such as diet, exercise, alcohol, smoking and caffeine consumption and dietary sodium intake and offer appropriate lifestyle advice. • Record the results of all investigations and assessment in Mary’s notes.

  22. Comparison of a Sample of Global Coronary and Cardiovascular Risk Scores • Note: Table 2 in full-text Guideline

  23. JNC 7: CVD Risk Factors • Hypertension* • Cigarette smoking • Obesity* (BMI >30 kg/m2) • Physical inactivity • Dyslipidemia* • Diabetes mellitus* • Microalbuminuria or estimated GFR <60 ml/min • Age (older than 55 for men, 65 for women) • Family history of premature CVD (men under age 55 or women under age 65) • *Components of the metabolic syndrome.

  24. Case scenario 1 : Mary • Question 1.3 • You identify her dietary sodium intake is greater than recommended levels. • NICE PH25 on prevention of cardiovascular disease recommends that as part of preventing cardiovascular disease at a population level there should be a reduction in salt intake. • By 2015 an adults maximum intake of salt per day should not exceed 6g and by 2025 this should be reduced to 3g • What advice would you offer?

  25. Case scenario 1 : Mary • Answer 1.3 • You would advise that healthy diet and regular exercise can reduce blood pressure. • You would also encourage her to keep her dietary sodium intake low as this can reduce blood pressure.

  26. Dietary Approaches to Stop Hypertension (DASH)

  27. Case scenario 1 : Mary • Question 1.4 • The result of Mary’s ABPM shows daytime average blood pressure of 145/92 mmHg. • What would your diagnosis and your next steps be?

  28. Case scenario 1 : Mary • Answer 1.4 • This result shows that Mary has stage 1 hypertension. • If you had not already done so (answer 1.2), you would estimate cardiovascular risk and offer tests for target organ damage. • You would use the results of the cardiovascular risk assessment to discuss prognosis and healthcare options with Mary. • Continue to ascertain information about her lifestyle in order to provide tailored lifestyle advice in accordance with the guideline on areas such as diet (including sodium and caffeine intake) and exercise and alcohol consumption. • See the definitions slide for ABPM diagnosis criteria

  29. JNC 7: Target Organ Damage • Heart • Left ventricular hypertrophy • Angina or myocardial infarction • Atrial fibrillation • Heart failure • Brain • Stroke or transient ischemic attack • Chronic kidney disease • Peripheral arterial disease • Retinopathy

  30. LEFT VENTRICULAR HYPERTROPHY • The Sokolow-Lyon index: • S in V1 + R in V5 or V6 (whichever is larger) ≥ 35 mm (≥ 7 large squares) • R in aVL ≥ 11 mm • Left axis deviation (QRS of -30° or more)

  31. Retina Normal and Hypertensive Retinopathy • A • B • C • NormalRetina • HypertensiveRetinopathy • A: Hemorrhages • B: Exudates (Fatty Deposits) • C: Cotton Wool Spots (Micro Strokes)

  32. Stage I- Arteriolar Narrowing • ArteriolarNarrowing

  33. Stage II- AV Nicking • AV Nicking • AV Nicking • AV Nicking

  34. Stage III- Hemorrhages (H), Cotton Wool Spots and Exudats (E) • H • E

  35. Stage IV- Stage III+Papilledema

  36. Case scenario 1 : Mary • Question 1.5 • The results of the investigations for target organ damage and formal assessment of cardiovascular risk are: • no evidence of target organ damage • 10-year cardiovascular risk less than 20%. • Nothing abnormal was detected in the other investigations you organised. • What is your next step and what treatment and follow up would you offer?

  37. Case scenario 1 : Mary • Answer 1.5 (continued) • Mary does not have target organ damage, established cardiovascular disease, renal disease, diabetes or a 10-year cardiovascular risk equivalent to 20% or greater, therefore you would not offer antihypertensive drug treatment. • You would continue to provide further tailored lifestyle advice (recommendation 1.4.1 – 1.4.9) periodically in accordance with the NICE clinical guideline. • The NICE clinical guideline recommends that you would provide Mary with an annual review of care to monitor blood pressure, provide her with support and discuss her lifestyle and symptoms.

  38. Aims of the talk • To diagnose hypertension • To treat hypertension • Why ? • Who ? • When ? • How ? • To what extend treat hypertension ?

  39. Goals of Treatment • Treating SBP and DBP to targets that are <140/90 mmHg • Patients with diabetes or renal disease, the BP goal is <130/80 mmHg • The primary focus should be on attaining the SBP goal. • To reduce cardiovascular and renal morbidity and mortality

  40. Benefits of Treatment • Reductions in stroke incidence, averaging 35–40 percent • Reductions in MI, averaging 20–25 percent • Reductions in HF, averaging >50 percent.

  41. Treatment guidelines (ESH/ESC 2007) • Average risk • Low added risk • Moderate added risk • High added risk • Very high added risk • ESH – ESC Guidelines Committee. J Hypertens 2007; 25: 1105–1187

  42. CBPM ≥140/90 mmHg & ABPM/HBPM ≥ 135/85 mmHg Stage 1 hypertension CBPM ≥160/100 mmHg & ABPM/HBPM ≥ 150/95 mmHg Stage 2 hypertension Care pathway • If target organ damage present or 10-year cardiovascular risk > 20% Offer antihypertensive drug treatment Consider specialist referral • If younger than 40 years Offer lifestyle interventions Offer patient education and interventions to support adherence to treatment Offer annual review of care to monitor blood pressure, provide support and discuss lifestyle, symptoms and medication

  43. Case scenario 1 : Mary • Question 1.6 • If Mary had been eligible to receive antihypertensive drug treatment, what should you consider when prescribing antihypertensive drugs for a woman of child-bearing potential?

  44. Hydraulic equation: Blood Pressure = Cardiac output (CO) X Resistance to passage of blood through precapillary arterioles (PVR) Physiologically CO and PVR is maintained minute to minute by – arterioles (1) postcapillary venules (2) and Heart (3) Kidney is the fourth site – volume of intravascular fluid Baroreflex, humoral mechanism and renin-angiotensin- aldosterone system regulates the above 4 sites All antihypertensives act via interfering with normal mechanisms Normal Blood Pressure Regulation

  45. The Renal response • Long-term blood pressure control – by controlling blood volume • Reduction in renal pressure - intrarenal redistribution of pressure and increased absorption of salt and water • Decreased pressure in renal arterioles and sympathetic activity – renin production – angiotensin II production • Angiotensin II: • Causes direct constriction of renal arterioles • Stimulation of aldosterone synthesis – sodium absorption and increase in intravascular blood volume

  46. Antihypertensive Drugs • Diuretics: • Thiazides: Hydrochlorothiazide, chlorthalidone • High ceiling: Furosemide • K+ sparing: Spironolactone, triamterene and amiloride MOA: Acts on Kidneys to increase excretion of Na and H2O – decrease in blood volume – decreased BP • Angiotensin-converting Enzyme (ACE) inhibitors: • Captopril, lisinopril., enalapril, ramipril and fosinopril MOA: Inhibit synthesis of Angiotensin II – decrease in peripheral resistance and blood volume • Angiotensin (AT1) blockers: • Losartan, candesartan, valsartan and telmisartan MOA: Blocks binding of Angiotensin II to its receptors

  47. Antihypertensive Drugs ß-adrenergic blockers: Non selective: Propranolol (others: nadolol, timolol, pindolol, labetolol) Cardioselective: Metoprolol (others: atenolol, esmolol, betaxolol)   MOA: Bind to beta adrenergic receptors and blocks the activity Calcium Channel Blockers (CCB): Verapamil, diltiazem, nifedipine, felodipine, amlodipine, nimodipine etc. MOA: Blocks influx of Ca++ in smooth muscle cells – relaxation of SMCs – decrease BP ß and α – adrenergic blockers: Labetolol and carvedilol α – adrenergic blockers: Prazosin, terazosin, doxazosin, phenoxybenzamine and phentolamine MOA: Blocking of alpha adrenergic receptors in smooth muscles - vasodilatation

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