Summary
A review of the general nature of cardiovascular structural adaptation and how this per se normal process becomes of key haemodynamic importance for the development of primary hypertension, particularly with respect to the gradual elevation of systemic precapillary resistance is presented. Because of the structural ‘upward resetting’ of the haemodynamic equilibrium, antihypertensive therapy in reality faces afar more formidable task in chronic hypertension than merely ‘normalising’ a supposedly raised vascular smooth muscle activity or/and cardiac output. Rather, it must bring about sub -normal activity levels to normalise the arterial pressure level, and only when such a pressure lowering has been sustained enough to allow for structural regression towards normal dimensions is a true normalisation achieved. However, the process of structural regression takes time and is complicated by the fact that the often long duration of the high- pressure state has led to structural changes which can be quite difficult to reverse.
Finally, physiological- haemodynamic reasons are discussed which direct pharmacological interferences preferentially towards the pronounced myogenic activity of the precapillary resistance vessels, which both in normo- and hypertension is by far the most dominating element behind resting smooth muscle activity in these vessels and is, moreover, especially dependent on influx of external calcium ions., As the raised precapillary resistance (by means of ‘structural autoregulation’) represents the key element behind the pressure rise in established hypertension, such a pharmacological interference is directed towards the proper haemodynamic site and would not directly interfere with the neurohormonal integrat ive control of the circulation.
Similar content being viewed by others
References
Bevan, J.A.: Myogenic tone of vascular smooth muscle; in Ingelheim Workshop Series on Precapillary Vessels, VI. Cardiovascular Pharmacology (in press, 1985).
Celander, O. and Folkow, B.: A comparison of the sympathetic vasomotor fibre control of the vessels within the skin and the muscles. Acta Physiologica Scandinavica 29: 241–250 (1953).
Folkow, B.: Physiological aspects of primary hypertension. Physiological Reviews 62: 347–504 (1982).
Folkow, B.: Structural autoregulation — the local adaptation of vascular beds to chronic changes in pressure; in Nugent and O’Connor (Eds) Development of the Vascular System, pp. 56–79 (Ciba Foundation Symposium 100, Pitman Books London 1983).
Folkow, B.; Grimby, G. and Thulesius, O.: Adaptive structural changes of the vascular walls in hypertension and their relation to the control of the peripheral resistance. Acta Physiologica Scandinavica 44: 255–272 (1958).
Folkow, B.; Hallbäck, M.; Jones, J.V. and Sutter, M.: Dependence of external calcium for the noradrenaline contractility of the resistance vessels in spontaneously hypertensive and renal hypertensive rats, as compared with normotensive controls. Acta Physiologica Scandinavica 101: 84–97 (1977).
Folkow, B.; Hansson, L. and Sivertsson, R.: Structural vascular factors in the pathogenesis of hypertension; in Robertson (Ed.) Handbook of Hypertension Vol. 1, Clinical Aspects of Essential Hypertension, pp. 133-150 (Elsevier 1983).
Folkow, B. and Neil, E.: Circulation (Oxford University Press 1971).
Friberg, P.; Folkow, B. and Hallbäck-Nordlander, M.: Changes in geometry of the left ventricle in response to different hemodynamic alterations. 10th Scientific Meeting of the International Society for Hypertension, Interlaken, Switzerland, June, 1984.
Göthberg, G. and Folkow, B.: Age-dependent alterations in the structurally determined vascular resistance, pre- and post-glomerular resistance ratio and glomerular filtration capacity in kidneys, as studied in aging normotensive rats and spontaneously hypertensive rats. Acta Physiologica Scandinavica 117: 547–555 (1983).
Gross, F. (Ed.): Handbook of Experimental Pharmacology, Vol. 39. Antihypertensive Agents (Springer, Berlin 1977).
Guyton, A.C.; Coleman, T.G.; Cowley, A.W.Jr; Manning, R.D. Jr; Norman, R.A. Jr and Ferguson, J.D.: A systems analysis approach to understanding long-range arterial blood pressure control and hypertension. Circulation Research 35: 159–176 (1974).
Haraldsson, B.; Nilsson, H. and Folkow, B.: Structurally reduced distensibility of cardiovascular ‘low-pressure’ compartments in primary hypertension, as studied in spontaneously hypertensive rats (SHR). Acta Physiologica Scandinavica 112: 473–480 (1981).
Jones, J.V. and Thorén, P.: Characteristics of aortic baroreceptors with non-medullated afferents arising from the aortic arch of rabbits with chronic renovascular hypertension. Acta Physiologica Scandinavica 101: 286–293 (1977).
Korner, P.I.: Causal and homeostatic factors in hypertension. Sixth Volhard Lecture. Clinical Science 63: 5s–26s (1982).
Korner, PL: The pathogenesis of hypertension: ‘The Baker Concerto.’ Clinical and Experimental Hypertension: Part A — Theory and Practice A6: 565–586 (1984).
Löfving, B. and Meiiander, S.: Some aspects of the basal tonc of the blood vessels. Acta Physiologica Scandinavica 37: 134–141 (1956).
Lundin, S.; Folkow, B. and Rippe, B.: Central blood volume in spontaneously hypertensive rats and Wistar-Kyoto normotensive rats. Acta Physiologica Scandinavica 112: 257–262 (1981).
Lundin, S.; Friberg, P. and Hallbäck-Nordlander, M.: Left ventricular hypertrophy improves cardiac performance in spontaneously hypertensive rats. Acta Physiologica Scandinavica 114: 321–328(1982).
Lundin, S.; Friberg, P. and Ricksten, S.-E.: Diastolic properties of the hypertrophied left ventricle in spontaneously hypertensive rats. Acta Physiologica Scandinavica 118: 1–9 (1983).
Mellander, S. and Johansson, B.: Control of resistance, exchange and capacitance function in the peripheral circulation. Pharmacological Reviews 20: 117–196 (1968).
Mulvany, M.J.: Do resistance vessel abnormalities contribute to the elevated blood pressure of spontaneously hypertensive rats? A review of some of the evidence. Blood Vessels 20: 1–22 (1983).
Pfeffer, M.A.; Pfeffer, J.M. and Frohlich, E.: Pumping ability of the hypertrophying left ventricle of the spontaneously hypertensive rat. Circulation Research 38: 423–429 (1976).
Ricksten, S.-E.; Yao, T. and Thorén, P.: Peripheral and central vascular compliances in conscious normotensive and spontaneously hypertensive rats. Acta Physiologica Scandinavica 112: 169–177(1981).
Sivertsson, R.: The hemodynamic importance of structural vascular changes in essential hypertension. Acta Physiologica Scandinavica (Suppl. 343): 1-56 (1970).
Sleight, P. (Ed): Arterial Baroreceptors and Hypertension, (Oxford University Press, London 1980).
Sutter, M.C.: Quantitative effects of external calcium concentration on contraction of rat portal vein compared to thoracic aorta. Acta Physiologica Scandinavica 98: 266–268 (1976).
Sutter, M.C.; Hallbäck, M.; Jones, J.V. and Folkow, B.: Contractile responses to noradrenaline: Varying dependence on external calcium of consecutive vascular segments of perfused rat hindquarters. Acta Physiologica Scandinavica 99: 2166–2172 (1977).
Thorén, P.; Andresen, M.C. and Brown, A.M.: Resetting of aortic baroreceptors with non-myelinated afferent fibers in spontaneously hypertensive rats. Acta Physiologica Scandinavica 117: 91–97 (1983).
Thorén, P. and Ricksten, S.-E.: Cardiac C-fiber endings in cardiovascular control under normal and pathophysiological conditions; in Abboud and Gilmore (Eds) Disturbances in Neurogenic Control of the Circulation, pp. 17-31 (American Physiological Society 1981).
Weiss, L.: Aspects of the relation between functional and structural cardiovascular factors in primary hypertension. Experimental studies in spontaneously hypertensive rats. Acta Physiologica Scandinavica (Suppl. 409): 1-58 (1974).
Wolinsky, H.: Long-term effects of hypertension on the rat aortic wall and their relation to concurrent aging changes. Circulation Research 30: 301–309 (1972).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Folkow, B. Vascular Changes in Hypertension Therapeutic Implications. Drugs 29 (Suppl 2), 1–8 (1985). https://doi.org/10.2165/00003495-198500292-00003
Published:
Issue Date:
DOI: https://doi.org/10.2165/00003495-198500292-00003