As far as we can as yet judge, the first objective symptom that points to threatening sclerosis is a more or less continuous rise of systolic pressure, as measured by the sphygmomanometer (the use of this instrument is imperative). The following extract from the Lancet January 8, 1916, puts the matter very clearly: “The clinical value of observations on Blood Pressure is doubted only by those who have never made them. It is true that the finger can detect some difference in pulse tension, but it is often entirely at fault, since it can only estimate total pressure, thus missing a high pressure, if the volume be small. In the same way, although the hand can detect differences of temperature, it cannot replace the thermometer. The sphygmomanometer has enlarged our ideas, cleared up difficulties in diagnosis, and helped in prognosis. This has naturally reacted on treatment; it has enlarged our ideas on ‘heart failure.’ The heart is adjusted to work at certain pressures, and though within considerable limits it can adjust itself to variations, those limits may be exceeded.”
There are subjective signs, especially in middle age, which point the same way, but we can seldom get hold of patients at this early stage. These are chiefly shortness of breath, on slight exertion, which makes a man realize that he has almost suddenly got out of condition, that the elasticity of youth has gone; a feeling of brain fatigue, quite out of proportion to the work done; sometimes giddiness and tinnitus, especially on stooping. Whether these symptoms appear before there is a rise of pressure it is difficult to say, but they should certainly in all cases suggest blood pressure testing. The key to the patient’s future then lies first in our hands, and then in his, life or death, health or disease, a full working life and happiness or incapacity and failure. The examination must be carefully made and frequently. The best time to take pressure is about two hours after food, when there has been a time of physical quiet, and no hurry or emotion. The position should be either recumbent or sitting in a chair, with the arm resting on a table (the muscles of the arm should not be in action), and the wrist should be on the same level as the heart. Pressure readings are higher when standing than sitting, and when sitting than lying down, the difference being from four to eight millimetres. In the early stages pressure varies a good deal, and will not show a rise at all times of day; in the early morning particularly it is often quite normal.
The question now arises, What is the normal? For our purpose we may leave out the question of pressures in childhood and early life, and may take the following figures as a fair average for our calculation:—
| From | 40 | years | of age to | 50, 130 mm. to 135 mm. |
| 50 | " | " | 60, 135 mm. to 145 mm. | |
| 60 | " | " | 70, 140 mm. to 150 mm. |
I think there can be no doubt that there is a period, often of months, when there is only increased contraction of the muscular coats of the arteries. This is due to the increased strain of life generally, and is in consonance with our experience generally of muscular overgrowth and overwork. Huchard called this “the pre-sclerotic stage.”
I think we may say that any pressures at about fifty years of age below 120 mm. are a sign of debility, and above 150 mm. are signs of threatening arterial trouble. Over sixty there is a natural tendency to hardening of the arteries, and many men seem to lead healthy lives with a pressure of 160 mm. Still, with a pressure of that height they cannot afford to put any excessive strain on their arteries. At about eighty there is a decided tendency for pressure to fall, even if there has been plus pressure before. It is rare to find high pressure over ninety for the reason that people who live to that age must have had healthy hearts and arteries all the time, but even in them we not infrequently find passing rises; these are often missed, but they cause much mental distress and even delusions, but at this age, under treatment, the pressure soon falls and the mind clears. I had one lady who lived to ninety-seven, and during the last six years of her life she had visions and slight delusions when her pressure rose, but in the intervals her mind was quite clear. She learned to recognize the cause of her trouble.
This rule of normality stands pretty true for the majority of people, but in practice we find a good many individual exceptions: in such, the personal equation has to be solved. Women often, even in advanced age, have very low pressures, even 120 mm. to 125 mm., and seem to carry on quite well. They again get a period of high pressure about the climacteric, which with careful treatment disappears, and their subsequent years from about fifty-five to seventy-five are often the best and the happiest working years of their lives. It is not uncommon both in men and women who have led strenuous but healthy lives to find, about sixty, steady pressures of 160 mm. to 170 mm., without causing any symptoms of illness or distress. These people, though one cannot consider them safe lives from the insurance point of view, have learned to manage themselves and seem to have set up a new, personal normal which is an effective compromise. If one has been able by careful observation to satisfy oneself about such a case, it would certainly be unwise to try to lower that pressure point. Even in cases where there is manifest disease of some standing, one has to find out the best working point of pressure for the individual. They can live and work fairly comfortably at 160 mm. or 170 mm., but if you lower the pressure to 140 mm. or 150 mm., their hearts get irregular and they feel good for nothing; but I think we may make a working rule that a pressure of 180 mm. and over should be lowered; the danger to the cerebral arteries is too great. Even in the early stages a careful watch should be kept on the kidneys. If albumen appears, it makes the prognosis more grave, but it should cause no despair. Mahomed and the early observers thought that kidney disease was almost inevitable sooner or later, but further experience has shown us that many cases live for years and then die without albuminuria. In other cases it is often transient and responds to treatment.
Hitherto I have only dealt with systolic pressure, but the diastolic pressure in senility and sclerosis is a matter of much importance, and helps us both in treatment and prognosis. Brunton said: “The systolic pressure shows the maximum height to which blood pressure is raised by the wave of blood driven into the aorta by the contraction of the left ventricle. It thus indicates in a general way the strength of the ventricle. The diastolic pressure shows the minimum to which the blood pressure sinks during the interval when no blood is coming into the aorta from the heart, and the arterial system is emptying itself through the capillaries into the veins. It therefore indicates generally the degree of contraction or relaxation of the capillaries.”
For practical purposes we want to know the pulse pressure, and this is roughly estimated by subtracting the diastolic from the systolic. A systolic pressure of 140 and a diastolic of 100 would give a pulse pressure of 40, which is about right. Any pulse pressure of over 40 points to hyper-tension, and under 20 to hypo-tension. The diastolic pressure is more constant than systolic pressure, and is not so susceptible to disturbing external influences; it is therefore a surer guide in estimating hyper-tension. A continuous diastolic pressure of over 100 certainly points to continuous hyper-tension. If the difference between the systolic and the diastolic is normal, about 30 to 40, we may conclude that the heart’s impulse is normal, and that even in conditions of marked sclerosis there is efficient compensation.
Sir Clifford Allbutt says (in Diseases of the Arteries, vol. i, p. 92): “It is in the experience of us all that, as the walls of the great vessels lose their elasticity, the systolic pressure mounts above its proportion to the diastolic which falls. In aortic regurgitation the difference between the systolic and diastolic figures may be enormous, as much as 105 mm. to 210 mm. In a certain ‘Adams Stokes’ case of my own, at a pulse rate of 32, the systolic pressure was 180, the diastolic 90 mm. Thus, with the difference between the two pressures waxing as the resilience wanes, the blood pressure moves more suddenly and largely, bangs more, and thus racks the machinery. The greater vaso-motor lability in youth has a like effect, but the vessels are then much more resilient and energy is stored. In an early hyperpietic, or nephritic subject the systolic exorbitancy may be considerable or variable, while the diastolic is steadily in excess. As age advances the amplitude increases to 80 and upwards; a systolic pressure of 160 mm. may be associated with a diastolic of 75 mm. or 80 mm.”