Importance of Average Hemodynamic Pressure in General Practice

 

G.A.Starkov, Domodedovsky District Central Hospital.

ЦРБ Домодедово, г.Москва.

Fixed attention of Medicine for Essential Hypertension is well-founded. The immediate cause of cardiac insufficiency and stroke merits more attention, taking into account that hypertension takes the first place among chronic diseases and its rate among people older than 30 years comes to 80 percent. This data has been obtained from personal observations in 2000 – 2004. Any practitioner can easily verify it. It is enough to ask a patient whether he(she) ever suffered from a headache when not ill with any illness, such as cold. The headache is so widespread that people do not regard it as symptoms of a disease any longer. This fact is often ignored by medical statistics, practitioners and even medical science. However the headache of hypertension nature at early stage and eclipse period has, as the author accentuates, well-defined features: dull, constricting, not always localized, slightly disseminated pain, or else more disseminated pain with definite localization in regio frontalis capitis, regio parietalis capitis or regio occipitalis capitis . The pain may span in two regions – frontoparietal or occipitoparietal, sometimes – in all the three regions. As a rule this pain is double-sided, but may be one-sided, it usually lasts half an hour or more and calms down after sleep. The author hopes that this description will be included in manuals of propaedeutics and this should happen only because such a headache is caused by rise of average hemodynamic blood pressure. These criteria (as well as other main indices of system hemodynamics, i.e. Stroke Volume, Minute Volume, General Peripheral Vascular Contraction (GPVC)) are given little attention in modern literature with regard to their practical use for treatment of hypertension. And we should admit that it may seem strange to treat a disease the main feature of which is system hemodynamics abnormality - blood pressure rise – without taking into account the main characteristics of this hemodynamics. However, such a strange fact may have a positive side – the practitioners today are as talented as they were before, when they diagnosed exactly without modern laboratory and instrumental research. The present-day practitioners have such amazing instrument as demonstrative research. Yet, the results of this research may depend strongly on the composition of the examined group on the basis of any important symptoms which are ignored or not taken into consideration by research workers. For example, the one examined group is mainly made up of patients suffering low GPVC. Then, the role of calcium antagonists is analyzed. This gives the rise of mortality as a result. The other careful research for the most part includes patients with high level of GPVS. Then the outcome is really contrary.

The reasoning cited above is necessary to convince the reader of importance of system hemodynamics indices. The main characteristic of hypertension is the average hemodynamic pressure (AHP). For measuring AHP the “APKO- 8” device (the Hardware and Software Complex made by OOO “Globus”, Belgorod, Russia) was used. All the blood pressure figures given below are significant only on condition that they were obtained in standard measurement circumstances after Korotkov – the patient is sitting relaxed, the pressure is measured in five minutes of rest. If the pressure is within the limits of 75- 85 mm , the patient has no pain described above. The initial pain may reveal when the pressure is equal or approaches 88 mm after N.N.Savitsky. Why this happens to practically healthy people? Does not this happen because the limits between health and illness are fuzzy under the influence of the method used, its exactness and individuality.

The systems of ABP regulation are self-controlled by the organism. Any figures in a self-regulating system are of global nature. The fluctuation amplitude of AHP as for healthy people reaches 5 mm in both directions – under equal conditions! The maximum point of AHP rise may exceed the normal limits. The rise of AHP in cerebral blood vessels may provoke this typical pain when the nociceptive system functions normally.

If we look closely at the patients upon reception, we can easily note that they all have different weights and heights, they have, respectively, different hemodynamics, and their blood pressure norms are supposed to be different. The author have analyzed the rate of AHP for 342 healthy persons and proposed a universal AHP norm - 46 mm per 1 m 2 of the body surface. If the AHP exceeds this figure, the patient is supposed to have hypertension. No matter what systolic and diastolic pressure rate the patient has, because these rates are derived first of all of the AHP and, to a lesser extent, of some other figures of system hemodynamics. The author has noted that under slight rise of AHP appears the symptom of meteo-sensibility – the second symptom of early and latent hypertension. The third symptom may also appear: flashing silvery spots in the field of vision. Moreover, sometimes the fluorography may diagnose left ventricular hypertrophy. All this may happen even if the ABP figures are under 140 / 90 mm but the AHP rate exceeds 46 mm per 1 m 2 of the body surface.

The author uses AHP as the main index of hypertension severity and degree of the disease. Since the figures of diastolic and systolic pressure are not used for this, the author is free of the World Health Organization grading by 1-2-3. As we would like this classification to be understandable by the patients, the old WHO names are still in use: mild hypertension, moderate hypertension, serious hypertension. Besides, one more name is added because of the danger of the disease: extremely serious hypertension. This is done in order to make positive use of semantic perception of this classification by the patients. One may defy serious hypertension or disregard it, but one have nothing to do but treat an extremely serious hypertension.

The number of examined patients is listed in the schedule below:

 

Schedule 1. Distribution of examined patients according to the hypertension severity

 

Healthy Mild hypertension Moderate hypertension Serious hypertension Extremely serious hypertension
Number of examined people 342 645 842 991 129
Percentage 11. 6 21. 9 28. 5 33. 6 4. 4
Average age 41 44 49 55 58
Average weight 69. 44 76. 79 81. 87 83. 94 82. 25

11. 6 percent of examined patients are healthy. This is not the hole population, but people, who appeared before General Practitioner with any complaints. The average age of this group, when the disease starts to become apparent is 42.5. The duration of the disease is about 17 or 20 years. In fact, the duration of the disease should be considered for every group – if the disease starts at the age of 15 or 20, its duration is much longer. The average weight increases pro rata the AHP and only on the stage of extremely serious hypertension (AHP > 140 mm ) there is a tendency to decrease. This fact can be explained like this: dystrophic active conditions are so acute and have reached such a high level, that they may influence the total weight of the organism. Further, if we examine those whose AHP exceeds 160 mm , their average weight is about 78.94 kg . The average age in this group is 59. The diagram below serves to demonstrate the variability of systolic, diastolic and average hemodynamic pressure depending on hypertension severity and brings out clearly that the most stable index is AHP.

 

Some interesting questions may emerge when we analyze this diagram. The author has been always interested, why, the rise of ABP, once started, never stops and progresses steadily? Does the organism need this, if so, why? One of the most probable answers, according to the diagram plotted: by this way the stability in blood pressure regulating systems functioning is acquired.

The other, more generalized question may consist in the following. For any self-controlling system of the organism, the extreme fluctuations have a vector directed to bigger safety for the organism. Any self-controlling system is always back-connected and the regulation is effectuated “in response” of the signals of positive or negative effect. As a result, the controlled index varies at some average figure. But such fluctuations are not always the same. The greatest of them are aimed to one direction – in any circumstances the most acceptable for the organism. We can define it as a “striving for survival” or “liking for life”.

And when the system receives both positive and negative signals of equal strength, or the system keeps away of regulating, a slow process of drift to the greater safety for organism may be observed. In such a case the ABP rise is safer than its drop. The similar situation may be observed with glucose level – the drop is more dangerous than the rise. The same thing as for the coagulability control system and the appetite. In that way regulating systems abnormalities may appear. The common pathogenetic constituent for these diseases is the fact that the organism can not immediately consider such situations as abnormal, i.e. these diseases proceed without sanogenesis. The common clinical feature of these diseases includes imperceptible onset, slow, but persistent progressive development, longer duration, the need of constant, sometimes, lifelong treatment. The sickness rate is rather high for such diseases unlike the regulating systems failure diseases, opposite to them. Take for example diseases, following hypoglycemia and insular diabetes of 2 nd type, cachexy and obesity, low blood pressure and hypertension. The most illustrative example is rhythm disturbance – the number of extrasystols exceeds considerably the number of cardiac standstill episodes if monitored daily. In such a case some of the self-regulating (self-controlling) systems have intracellular location. These systems are adjusted with a sharp susceptibility of an impulse out of order, even if this impulse (signal) is not needed for the organism.

Another long-standing question is : why hypotonia (low blood pressure) is often diagnosed where it must not be – the AHP figures are normal but the ABP figures may be 90/60 – 110/70, and if the patient does not complain he/she is healthy. The self-controlling system sympathy can not change even if the organism is threatened with death. Thus, under hypertension condition, the organism priorities are changing in the course of the illness – the ABP rise becomes really dangerous at the extremely severe stage. But the rule -

For any self-controlling system of the organism, the extreme fluctuations have a vector directed to bigger safety for the organism – keeps on be effective. Nothing can make the system change the vector, nothing except the cases when some units of this system are blocked by medicines. This rule is so well-grounded in the self-regulating biological systems structure, that it may be considered as a law. Even among people examined by the author we can find its confirmation. The percentage of the persons affected with low blood pressure amounts to 1.2%, healthy people – 11.6%, people suffering from hypertension – 87.3%. One can also compare the number of patients ill with insular diabetes of 2 nd type and the number of those who suffer from hypoglycemia.

A great temptation for practitioners and unpleasant surprise for pharmacists then appear. It consists in finding a new mechanism and place of localization of the self-regulating system sympathy and turning it to the contrary. And, further on, the blood pressure will steadily decrease without supportive therapy. Let us assume that this sympathy for ABP regulating systems is determined by some albumen, synthesized by liver, and that people which had been ill with acute viral hepatitis may recover spontaneously from hypertension because the synthesis of such an albumen is decreased or stopped. Or else there is some zone in subcortical structures and its blockage after the stroke may normalize the ABP for some patients. And with all this going on, left ventricular and muscular hypertrophy are still observed, that is to say there are factors leading to ABP rise.

If we return to ABP we can notice that, though the persistent progress of hypertension is characterized by gradual rise of all ABP parameters, AHP has the least variability. Thus, this index allow to demonstrate to the patient his/her current position in hypertension progress from the very beginning to the end. The graph showing the changes in AHP according to hypertension severity may be named the life-line of hypertonic patient.

Upon the primary consultation the practitioner demonstrates to the patients his/her position corresponding to AHP. It is important to know both for the patient and for the practitioner that the AHP value is not static for the patient. Its permanent fluctuations to both directions are not considerable for healthy people, but they may become bigger with the progress of hypertension. Moreover, the designation of an extremely severe hypertension is valued because on this stage the AHP regular fluctuations may be so abnormal that they can exceed the bounds of the graph to the right side marking life incompatibility. The treatment is to be prescribed according to the algorithm (2). Its effectiveness may be evaluated in accordance with AHP position relative to the left side (health) or the right side (illness). When the treatment is just started it is easy to obtain positive results, but every next step towards the recovery come with more and more difficulty. The ABP regulating self-controlling systems has serious obstacles to meet – hypertrophied left ventricle, vessel muscular wall hypertrophy, increased number of Rhinin Aldosterone Angiotensin System receptors, hypertrophied systems of neuromediators and vasopressors synthesis. But for all that the problem is kept: the greater deviation from the level maintained may be directed only towards ABP rise. It is impossible to change this thing. And only on condition of maintaining AHP on the level close to normal during several years it is possible to obtain the reverse development of hypertrophies of different organs and systems. This must be the aim of treatment of any patient suffering from hypertension – principal AHP less than 89 mm . The formula of AHP determination after Hickam keeps its exactness and the criterion of principal AHP for the practitioners who can not measure AHP may be diastolic pressure equal to 75 mm or less. However we should remind that the exactness of evaluation on the basis of diastolic pressure is half as less again because of the difference in variability. As a rule, the ABP level can not be the criterion for principal pressure – its descriptiveness is not exact as for the goal attainment.

 

Sources:

 

•  N.N.Savitsky. “Biophysical grounds of blood circulation and clinical methods of hemodynamic research”. Leningrad, 1974

•  G.A.Starkov. “Envas and Average hemodynamic pressure”. Doctor.ru, 2004, No. 3, 19-21