I’m an 82-year-old man, and I take pills to lower my blood pressure. My doctor has changed the pills and the dosages many times, and now my blood pressure seems to have stabilized at a good level. My question is that in these past few weeks, the diastolic number is in the low 60s, which is low compared to the normal 80. My doctor says there is no problem with this at my age. Is that true? – S.B., Jerusalem Dr. Karen Djemal, award-winning family physician and medical director of the Terem Family Care Clinic on Jerusalem’s Gedud Ha’ivri Street, replies: This is a really interesting question, I will begin by defining some terms so that other readers can follow the discussion, and then proceed to your question. Blood pressure refers to the pressure that blood applies to the inner walls of the arteries. Arteries carry blood from the heart to other organs and parts of the body. Hypertension is the medical term for high blood pressure.An individual’s blood pressure (BP) is defined by two measurements: systolic pressure, the pressure in the arteries produced when the heart contracts (at the time of a heartbeat); and diastolic pressure, the pressure in the arteries during relaxation of the heart between heartbeats.Blood pressure is reported as the systolic pressure over the diastolic pressure – for example, 120/70. Normal blood pressure is defined as less than 120 systolic over less than 80 diastolic. Hypertension is defined as BP equal to or greater than 140/90.Hypertension is usually asymptomatic and is diagnosed after three separate high blood pressure measurements.The diagnosis is important because untreated high blood pressure increases the strain on the heart and arteries, eventually causing organ damage.High blood pressure increases the risk of heart failure, heart attacks, strokes and kidney damage, which are major causes of mortality in the West.The risk of these complications increases as blood pressure rises, (even above 110/75, which is still within the healthy range). In general, our blood pressure rises as we age, so that among the older population more than half of all individuals are diagnosed with hypertension.The good news is that lowering high blood pressure to healthy values reduces these risks. Numerous medications are available and in most cases can effectively reduce blood pressure levels to normal. However, the balance of this benefit must be weighed against the potential side effects of the medications, and for blood pressure values under 140/90, lifestyle changes that can significantly help, but incur no risk are the mainstay of treatment, and medications are not prescribed.These recommendations include reduction of dietary salt, weight reduction or maintenance of healthy body weight, reducing alcohol intake, smoking cessation and regular exercise. They are relevant also for all hypertensive patients, even those taking medication.In certain high-risk groups, such as diabetics, coronary and kidney patients, medications are started at lower BP measurements.Your question refers to statistical observations in clinical trials of the correlation between different blood pressure measurements and increased cardiovascular risks and overall mortality risks. Whereas cardiovascular risks increase as systolic BP rises, the relationship of diastolic BP to cardiovascular risk is not always linear. Whereas high diastolic BP (over 90 mmHg) raises cardiovascular risks in all age groups, some clinical trials have shown that in the older population, low diastolic pressures (under 70 mmHg to 75 mmHg) also increase all-cause mortality. This would mean, as you suggest in your question, that lowering diastolic BP too much could actually be harmful.It is important to add that the clinical evidence for this is somewhat conflicting.Other trials have suggested low diastolic BP occurs in sub-populations of patients who have significant underlying chronic disease that increases both their cardiovascular risk and general health risks.In these cases, lowering the diastolic BP therapeutically does not add to these pre-existing risks. Additionally, in the Systolic Hypertension in the Elderly Program (SHEP), treated older adult patients with isolated systolic hypertension (and an initial diastolic pressure averaging 77 mmHg) had a lower incidence of both cerebrovascular and coronary events, despite a reduction in the diastolic pressure to below 70 mmHg. From this we learn that the overall benefit of reducing the systolic BP outweighs the potential risk in reducing the diastolic BP, even to under 70 mmHg. Other studies have also backed up this observation.In clinical practice, as long as the patient feels well and is asymptomatic – specifically, does not feel light-headed or overly fatigued and has not had any fainting spells – we are not overly concerned about low diastolic blood pressure measurements. We must be guided by the clinical response of the individual patient, and clearly, careful monitoring is advised when treating older adult patients, especially those who have low diastolic pressures when starting treatment or who “drop” their BP dramatically with treatment.Guidelines about target BP in the elderly are unclear, although higher BP measurements are often more acceptable, and the risks of side effects from overtreatment – and the potential adverse drug combinations – are much higher among the elderly. In many cases, the level of systolic blood pressure that is reached with two or three anti-hypertensive medications (even if greater than 140 mmHg) may be a more reasonable goal if the diastolic BP is less than 60 mmHg.In practicing the “art of medicine,” there are no hard-and-fast rules for everyone. We need to be guided by the particular health status of our patient rather than his chronological age and, as always, need to work together and communicate well to achieve optimal care. This may mean different target blood pressures for different people. ■ Rx for Readers welcomes queries from readers about medical problems. Experts will answer those we find most interesting.Write Rx for Readers, The Jerusalem Post, POB 81, Jerusalem 91000, fax your question to Judy Siegel-Itzkovich at (02) 538- 9527, or e-mail it to jsiegel@jpost.com, giving your initials, age and place of residence.
