Chapter 7. Atherosclerosis and hypertension

Chapter 7. Atherosclerosis and hypertension E. E. MATOVA & A. M. VIHERT Autopsy studies ofatherosclerosis of the aorta and the coronary arteries were carried out in 3134 subjects with essential hypertension. A comparison was made with low, average, and high atherosclerosis groups. Essential hypertension wasfound to accelerate the development of all types ofaortic lesion, except fatty streak, as compared with the standardized average atherosclerosis group, and to accelerate the development of fibrous plaque but not complicated and calcified lesions as compared with the high atherosclerosis group. The extent offibrous plaque in the coronary arteries was greater in the essential hypertension group than in the low and standardized average atherosclerosis groups but did not differ from that in the high atherosclerosis group. The extent of complicated and calcified lesions and the prevalence ofcoronary stenosis were higher in the high atherosclerosis group than in cases of hypertension. Geographical differences in atherosclerosis among hypertensives in different towns reflected the findings for the whole material. Symptomatic hypertension was found to accelerate aortic atherosclerosis at least to the same extent as essential hypertension. It was conducive to coronary atherosclerosis but not to the same extent as essential hypertension. Coronary stenosis and various manifestations of coronary heart disease were rare in symptomatic hypertension. Atherosclerosis in relation to essential hyperten- sion has been mainly studied in hospital autopsy material, and most authors believe that hypertension is conducive to atherosclerosis. Comparative epi- demiological studies of atherosclerosis in cases with and without essential hypertension have supported the view that arterial hypertension has an athero- genic effect (13,17). Many questions as to the rela- tionship between atherosclerosis and hypertensive disease remain to be answered, however. Thus it is not clear, for instance, to what extent the athero- genic role of hypertension varies with sex, age, and geographical location; whether the localization and character of atherosclerotic changes are different in patients with hypertension and without hyperten- sion; and what is the relationship between athero- sclerosis and symptomatic hypertension. MATERIAL AND METHODS The aorta and coronary arteries were studied in 3134 subjects with essential hypertension, including 1548 males aged 20-89 and 1586 females aged 40-89. The diagnosis of essential hypertension was based on clinical information, as described in Chapter 1. The cases of essential hypertension were grouped in the following ways: 1. All cases of essential hypertension, irrespective of cause of death. 2. A subgroup in which essential hypertension was the main disease and the cause of death. (This subgroup is referred to as " hypertensive deaths ".) 3. Symptomatic hypertension. The hypertensive deaths included those cases for which, in addition to the explicit indication of hypertension in the basic data form, the principal disease was one of the following: uraemia, gangrene, hypertensive heart disease, coronary thrombus, coronary occlusion (not thrombus), myocardial infarct, aneurysm of the aorta, thrombus of any artery, pulmonary embolism, cerebral haemorrhage, encephalomalacia, cerebral pseudocyst, or contracted kidney. Cases of diabetes mellitus were excluded, since this disease is known to influence the course of athero- sclerosis. The number and prevalence of cases of essential hypertension and hypertensive death and the prevalence of hypertension in the different towns are shown in Table 19. Among all those aged 40-79 who died from natural causes, essential hypertension was recorded in 21 % of men and 23% of women. Hypertensive deaths were recorded in 16% of men and 17% of women. BULL. WORLD HEALTH ORGAN., Vol. 53, 1976 -5393470 E. E. MATOVA & A. M. VIHERT Table 19. Number of cases of essential hypertension (A) and hypertensive death (B) (diabetes excluded), by age and sex, and proportion of all natural deaths (40-79 years) Age group Malm6 Prague Ryazan Yalta Tallin Total A B A B A B A B A B A B Males 20-29 0 0 0 0 4 4 2 0 4 3 10 7 30-39 2 2 1 1 24 17 5 5 15 14 47 39 40-49 11 12 12 8 32 25 16 10 40 35 111 90 50-59 57 41 45 40 77 62 47 31 134 125 360 299 60-69 149 104 94 61 69 59 60 43 161 141 533 408 70-79 163 108 106 68 21 16 16 12 94 88 400 292 80-89 32 18 35 23 0 0 2 1 18 16 87 58 Total 414 285 293 201 227 183 148 102 466 422 1548 1193 % of all natural deaths 16 11 17 12 27 22 24 16 30 27 21 16(age 40-79) Females 40-49 11 10 10 4 13 10 9 6 15 13 58 43 50-59 40 18 40 30 24 21 34 24 53 50 191 143 60-69 110 67 96 72 73 60 65 44 198 170 542 413 70-79 185 118 171 119 29 22 27 21 145 129 557 409 80-89 76 41 106 72 4 4 11 12 41 37 238 166 Total 422 254 423 297 243 117 146 107 452 399 1586 1174 % of all natural deaths 19 12 23 16 23 19 27 19 28 24 23 17(age 40-79) Comparison of the reported frequency of essential hypertension in the different towns with the total number of deaths from natural causes revealed that the smallest percentage of hypertensive cases was in Malmo (15% of men and 19% of women), followed by Prague, Ryazan, and Yalta, with the highest percentage being recorded in Tallin (29% of men and 28% of women). These figures, however, may not reflect the true situation since information on hypertension was missing in 20 ± 10% of all cases. PREVALENCE OF ATHEROSCLEROTIC LESIONS IN ESSENTIAL HYPERTENSION Abdominal aorta Fatty streak was encountered in the abdominal aorta in 88% of men and 92% of women with hypertension (Table 20). In the high atherosclerosis group, the prevalence of fatty streak in the aorta was the same as in essential hypertension, while in the low atherosclerosis group fatty streak was found significantly more frequently than in hypertension. In the low atherosclerosis group the prevalence of fatty streak in the aorta was also higher than in those with hypertension. Fibrous plaque was equally common in all three groups in men; in women, however, it was slightly less common in the low atherosclerosis group. Aortas with fibrous plaque and fatty streak only were significantly more frequent in the low athero- sclerosis group than in the essential hypertension group in both sexes. Calcified and complicated lesions in men and women with essential hyperten- sion occurred as frequently as in the high athero- 540 ATHEROSCLEROSIS AND HYPERTENSION Table 20. Prevalence (%) of lesions in the age-standardized values abdominal aorta (all towns combined), Fatty Fatty steak Fatty Fibrous Com- Calcified RaisedGroup stea + fibrous plicated lein lsosstekonly plaque streak plaque lesions lein lsos only Males Essential hypertension 2.8 24 88 97 69 53 97 Symptomatic hypertension 2.8 39 92 97 61 48 97 High atherosclerosis 0.9 23 90 99 72 50 99 Low atherosclerosis 4.3 46 96 96 41 42 96 Females Essential hypertension 3.3 41 92 97 45 48 97 Symptomatic hypertension 0 31 85 100 48 54 100 High atherosclerosis 4.0 36 89 96 54 51 96 Low atherosclerosis 9.9 62 95 90 22 31 90 sclerosis group but significantly more frequently than in the low atherosclerosis group (Table 20). Left anterior descending coronary artery Fatty streak was found in 75 % ofmen and 88% of women with essential hypertension (Table 21). In men, the prevalence of fatty streak was the same in the essential hypertension group as in the high atherosclerosis group but significantly lower than in the low atherosclerosis group. In women, fatty streak was significantly more frequent in the essential hypertension group than in the high atherosclerosis group. Coronary arteries with fatty streak only were found significantly less frequently in the hyper- tension group than in the low atherosclerosis group. Fibrous plaque was found in 98 % of men and 91 % of women with hypertension, i.e., its prevalence was similar to that in the high atherosclerosis group but higher than in the low atherosclerosis group. In the essential hypertension group, the prevalence of fatty streak with fibrous plaque only was significantly lower than in the low atherosclerosis group but Table 21. Prevalence (%) of lesions in the left anterior descending coronary artery (all towns combined), age-standardized values Fatty Fatty streak Fatty Fibrous CoIm Calcified RaisedGroup streak only +plfqOuS streak plaque plesions lesions lesions only Males Essential hypertension 1.4 46 75 98 22 46 98 Symptomatic hypertension 5.7 54 87 94 19 38 94 High atherosclerosis 0.9 31 73 99 33 57 99 Low atherosclerosis 4.2 66 85 95 7 30 95 Females Essential hypertension 8.1 67 88 91 11 27 91 Symptomatic hypertension 2.8 64 87 97 5 35 97 High atherosclerosis 5.3 52 81 94 22 39 94 Low atherosclerosis 17 80 87 81 2 18 82 541 E. E. MATOVA & A. M. VIHERT exceeded that in the high atherosclerosis group. The prevalence of complicated and calcified lesions was higher in the high atherosclerosis group than in the essential hypertension group and higher in the hypertension group than in the low atherosclerosis group. EXTENT OF ATHEROSCLEROTIC LESIONS IN THE ABDOMINAL AORTA The development of atherosclerosis was similar in the essential hypertension and low atherosclerosis groups. One difference, however, was that in the hypertension group the change in the ratio of fatty streak to raised lesions occurred 10 years earlier than in the low atherosclerosis group, i.e., in the fourth rather than the fifth decade of life. The greatest increase in raised lesions occurred in the fifth decade of life (nearly twofold compared with the preceding decade). After the age of 60, the rate of atherosclerotic development in the aorta slowed down. Up to age 70, the area of raised lesions was greater in hypertensive men than in hypertensive women. After 70, the reverse was true. The age- standardized values for raised lesions in the abdomi- nal aorta were 58% for men and 54% for women, while the area of fatty streak below the age of 70 was greater in women (age-standardized values being 7.5% for women and 5.0% for men). There was no substantial difference between men and women as regards the total amount of atherosclerosis. Complicated lesions were more extensive in men than in women, especially in the age range 40-79 years. In the 80-89-years age group, men and women showed no substantial differences. Under age 70, no sex differences were found for calcified lesions but after age 70 their extent was much greater in women. When the extent of raised and calcified lesions in the essential hypertension group was compared with that in the low, standardized average, and high atherosclerosis groups, raised lesions occupied, in both men and women, a significantly greater area even than in the high atherosclerosis group. The extent of calcified lesions in men with hyper- tension significantly exceeded only that in the low atherosclerosis group; in women, the extent of cal- cified lesions was significantly greater than in the standardized average atherosclerosis group. Neither in men nor in women were differences found be- tween the hypertension and high atherosclerosis groups in the extent of calcified lesions. EXTENT OF CORONARY ATHEROSCLEROSIS Coronary atherosclerosis was mainly represented by fibrous plaque. The area of fatty streak was nearly constant with age. The greatest increase in the raised lesion in males took place during the fifth and sixth decades (1.5 times more than in the preceding decade) but changed little thereafter. In females, the rate of increase in raised lesions in the coronary vessels slowed down only after the age of 79. Raised lesions were at all ages most extensive in men. This was also true of the other types of lesion (except fatty streak) and the total amount of atherosclerosis, which was in contrast with the findings in the aorta, where no significant sex differences were found in the total area of atherosclerosis. For the three main coronary arteries the total amount of atherosclerosis and the complicated lesions were the same in the right coronary and left anterior descending arteries but smaller in the left circumflex artery in all age groups. Calcified lesions were significantly greater in extent in the left anterior descending artery than in the other branches, parti- cularly after the age of 50. The age-standardized values for calcified lesions were 4.7% and 2.20 in the left anterior descending artery, 2.6% and 1.2% in the right coronary artery, and 2.4% and 1.5%, in left circumflex artery in men and women, respect- ively. Comparison of coronary atherosclerosis in the essential hypertension group with that in the low, standardized average, and high atherosclerosis groups revealed that, in both men and women, raised lesions were significantly greater in extent in the hypertension group than in the low and stan- dardized average groups but not different from the high atherosclerosis group. Calcified lesions in the average coronary artery were significantly greater in extent in hypertensive men and women than in the low and standardized average atherosclerosis groups but significantly lower than in the high athero- sclerosis groups. CORONARY STENOSIS, MYOCARDIAL LESIONS, AND CEREBROVASCULAR LESIONS The frequency of coronary stenosis in the high atherosclerosis group was higher in all age groups than in the essential hypertension group in both men and women. On the other hand, the hypertension group had a significantly higher prevalence of steno- sis than the low and standardized average athero- 542 ATHEROSCLEROSIS AND HYPERTENSION sclerosis groups. Similarly, fresh myocardial infarc- tion and large scars were found less frequently in the essential hypertension group than in the high athero- sclerosis group but significantly more often than in the standardized average atherosclerosis group. Cerebrovascular lesions occurred significantly more often in the essential hypertension group than in the high atherosclerosis group. ATHEROSCLEROSIS IN THE HYPERTENSIVE DEATHS GROUP The essential hypertension group as a whole and the hypertensive deaths group showed no differences in the extent of raised and calcified lesions in the aorta. Since in the hypertensive deaths group death was in most cases associated with various manifesta- tions of atherosclerosis, the extent of coronary raised and calcified lesions and stenosis was greater in this group. They also had a greater frequency of fresh myocardial infarcts and large myocardial scars. Their mean heart weight was higher than that for the whole hypertension group. HEART WEIGHT Heart weight varied greatly in the hypertensive subjects, being below 400 g in 14% of hypertensive men and below 300 g in 6% of hypertensive women. The mean heart weight in hypertensive men and women was greater than in the low and standardized average atherosclerosis groups. The age-standard- ized heart weight in the hypertension group was 497 g for men and 429 g for women. It was significantly higher than in the high atherosclerosis group in both sexes. INTER-TOWN DIFFERENCES A comparative study of the extent of aortic atherosclerotic changes in essential hypertension among the populations of the five towns revealed differing degrees of such changes. Thus, men and women of Ryazan were found to have smaller age- adjusted values for the extent of raised lesions than those of the other cities (Table 22). The extent of aortic atherosclerosis was greatest in Malmo. Comparison of the total area of coronary athero- sclerosis in hypertension revealed that the area of raised lesions in the average coronary artery was smaller in Ryazan and Yalta than in the other towns. The extent of raised lesions in the coronary Table 22. Inter-town comparison of the extent of raised lesions (% of surface) in the average aorta and average coronary artery in essential hypertension (without diabetes), age-standardized values Town Average aorta Average coronary Males Malmo (M) 62.3 56.1 Prague (P) 60.2 57.2 Ryazan (R) 44.7 49.5 Yalta (Y) 56.9 43.6 Tallin (T) 56.7 60.1 Significance M, P, Y, T > R T, P > M, R, Y P>T M >Y Females Malmo 64.1 46.0 Prague 60.2 46.9 Ryazan 46.0 38.2 Yalta 53.8 37.5 Tallin 58.6 51.2 Significance M, P, T, Y > R T > P, M, R, Y arteries of both males and females was greatest in Tallin (Table 22). In Ryazan, men over 50 and women over 60 had the smallest percentage of stenoses. There was a low incidence of stenosis among women of Malmo who died when aged between 50 and 59 years. The incidence of myocardial lesions varied from one town to another, although most of the differ- ences were statistically insignificant. The incidence of myocardial lesions in hypertension was correlated in the different towns with that of stenosis; in towns where the incidence of stenosis was low there was generally a lower incidence of fresh myocardial infarction or large myocardial scar. ATHEROSCLEROSIS IN SYMPTOMATIC HYPERTENSION Enough cases of symptomatic hypertension were available to permit a separate analysis (Table 23). In most cases, particularly in the younger age groups, death occurred from renal failure. The prevalence of different atherosclerotic lesions in the abdominal aorta is shown in Table 20. Fatty 543 E. E. MATOVA & A. M. VIHERT Table 23. Number of subjects with symptomatic hypertension, by sex and age Age (years) Sex 20-29 30-39 40-49 50-59 60-69 70-79 Total Male 4 8 15 13 19 12 71 Female 4 5 9 28 17 16 79 streak and fibrous plaque only in men occurred more frequently in the symptomatic hypertension group than in the high atherosclerosis group. In contrast, complicated and calcified lesions were more frequent in the high atherosclerosis group than in the symp- tomatic hypertension group. The same pattern was observed for the coronary arteries (Table 21), the differences for complicated and calcified lesions in men being statistically significant. The prevalence of complicated and calcified lesions in the abdominal aorta and left anterior descending artery was a little lower in symptomatic than in essential hypertension in men. In women the differences were less clear-cut. The extent of raised lesions in the average aorta was greater in the symptomatic hypertension group than in even the high atherosclerosis group, and this difference was statistically significant in men. Calci- fied lesions in men with symptomatic hypertension were greater in extent than in the high athero- sclerosis group, but the differences were not statisti- cally significant. In the average coronary artery the extent of raised lesions in men with symptomatic hypertension was significantly lower than for the high atherosclerosis group but significantly higher than for the low atherosclerosis group. In women, values were closer to those for the high atherosclerosis group and significantly higher than those for the standardized average atherosclerosis group. In the case of calcified lesions the only significant difference found was that men with symptomatic hypertension had lesions of lesser extent than the high atherosclerosis group. The extent of raised aortic lesions was the same in the essential and symptomatic hypertension groups. There were no clear differences between the two groups as regards calcified lesions in the average aorta. Raised and calcified lesions in the coronary arteries in men and raised lesions in the coronary arteries in women were more extensive in the hyper- tensive deaths group than in the secondary hyper- tension group, and the difference was statistically significant. Men showed significant differences in the fre- quency of coronary stenosis, this being much greater in symptomatic (18 % of cases) than in essential hypertension (41 %). Women showed smaller differ- ences in the rate of stenosis (21 % in symptomatic and 30% in essential hypertension). Coronary thrombosis, fresh myocardial infarction, large myocardial scar, and cerebrovascular lesions were markedly more prevalent in both men and women in the hypertensive deaths and essential hypertension groups than in the symptomatic hyper- tension group. The heart weight was approximately the same in the two groups. DISCUSSION A widely held view is that hypertension is con- ducive to the development of atherosclerotic changes in arteries. This view is based mainly on clinical data on the rates of ischaemic heart disease and cerebro- vascular lesions in persons with hypertensive disease (4, 7, 15). Data suggesting enhanced atherosclerosis in hypertensive disease have been obtained in bio- chemical and experimental studies (1, 2, 6, 11). Epi- demiological studies evaluating atherosclerosis in hypertensive disease have shown that the severity of atherosclerosis in hypertensives is greater than in non-hypertensives, irrespective of the cause of death (13, 17). In this study the atherosclerotic changes in hypertensives were compared with atherosclerosis in different groups selected on the basis of the under- lying diseases, in particular in cases of athero- sclerotic and non-atherosclerotic death. The dynamics of atherosclerotic changes in the aorta and coronary arteries in the hypertensives observed in this study were very similar to those found in the whole study population. There was the usual evolution of fibrous plaque with the formation of complicated changes, ulcerations, haemorrhages, and calcification, without the predominance of any particular type of morphogenesis of atherosclerosis. The predominance of atherosclerosis in men over women has been reported by a number of authors (5, 9, 17) but in hypertensive subjects atherosclerosis is demonstrable only in the coronary arteries, while the area of aortic atherosclerotic lesions is substan- tially the same as in non-hypertensive men and women. Possibly the effect of hormonal factors, including the inhibitory effect of female sex hor- 544 ATHEROSCLEROSIS AND HYPERTENSION mones, on atherosclerosis (10, 14) is offset by haemodynamic factors. Study of the dynamics of individual types of atherosclerotic change in hypertension revealed some specific features. Thus, in the hypertension group fatty streak in the aorta was less extensive than in the low atherosclerosis group. This could mean that fatty streak in the hypertension group had to a large extent been converted into fibrous plaque. According to Giertsen (3) the amount of lipids in the aortic wall is greater in hypertensive than in normo- tensive subjects. Deposits of lipids in hypertension probably arise mainly in the area of fibrous plaques. The results of a comparative study of athero- sclerosis in essential hypertension varied with the composition of the control group. Fibrous plaques and complicated and calcified lesions of the aorta and coronary vessels were seen more frequently in the essential hypertension group than in the low athero- sclerosis group, but with the same frequency as in the high atherosclerosis group. In the coronary arte- ries, complicated changes and calcified lesions were found more often in the high atherosclerosis group. The frequency of calcified lesions in coronary arteries was correlated with that of coronary artery stenosis. In the hypertension group, stenoses occur- red more frequently than in the low and the stan- dardized average atherosclerosis group, but less often than in high atherosclerosis group. This fact appears to account for the less frequent finding of myocardial infarction and post-infarction cardio- sclerosis in those who had suffered from hyperten- sive disease compared with those who died of atherosclerosis and were free of hypertension. In hypertensive disease, cerebrovascular disturbances were met with more frequently at autopsy than in the high atherosclerosis group. Hypertensive disease appeared to promote an increase in the area of aortic fibrous plaques in comparison with the low and high atherosclerosis groups, but the area of aortic calcino- sis did not exceed that in the high atherosclerosis group. The atherogenic influence of hypertension was more strongly marked in the aorta than in the coronary arteries. In the hypertension group, only the raised area was increased compared with the low and standardized average atherosclerosis groups, while no differences were found in the raised area in coronary arteries between the hypertension and the high atherosclerosis groups. The calcified area in the coronary arteries was greater in the high athero- sclerosis group than in the hypertension group. The mean heart weight was increased in those with hypertension in all age groups. However, the heart weight did not exceed 400 g in 14% of hypertensive men and 300 g in 6% of hypertensive women. On the other hand, subjects dying from their first myo- cardial infarction and without clinically known hypertension had increased heart weight (see chap- ter 14). Thus our findings support the views of Mitchell & Schwartz (8) and of Sternby (17) that heart weight should not be used as a morphological criterion of hypertension. Atherosclerosis in hypertensives in the popula- tions of the five towns varied in the same way as in the material as a whole. This is in agreement with the results of Robertson & Strong (13), who studied atherosclerosis in hypertensive disease in population groups in various locations. Geographical differ- ences in selected groups thus reflect the general differences found between places. This statement is also consistent with the results obtained in both the present and the International Atherosclerosis Project studies and with those reported by Stamler (14), who found that the occurrence of ischaemic heart disease in hypertensives is low in countries where ischaemic heart disease is not widespread. On the other hand, in countries where it is widespread it is often com- bined with hypertensive disease. The same is true of the prevalence of coronary stenosis in hypertensive disease, stenosis being more frequent in those Euro- pean towns where coronary heart disease is frequent. The low rate of coronary stenosis in hypertensives in certain population groups suggests that there is no indispensable causal relation between hypertensive disease and ischaemic heart disease. The relationship between symptomatic hyperten- sion and atherosclerosis has not been adequately covered in the literature. The rare occurrence of clinical signs of atherosclerosis in patients with renal disease gave support to the opinion that azotaemic states inhibit the development of atherosclerosis (7, 12). The literature on atherosclerosis in persons with symptomatic hypertension is contradictory. This study indicates that symptomatic hypertension accelerates the development of aortic and coronary atherosclerosis. The extent of raised lesions in the aorta and coronary arteries in the symptomatic hypertension group was significantly higher than in the low atherosclerosis group. No certain differences were found in raised lesions in the aorta between the symptomatic hypertension and hypertensive deaths groups. While fibrous plaque was usually found in the 3 545 546 E. E. MATOVA & A. M. VIHERT coronary arteries of subjects with symptomatic hypertension and occupied a greater area than in the low and standardized average atherosclerosis groups, complicated and calcified lesions occurred less often in symptomatic hypertension than in the high atherosclerosis group. Coronary stenosis was found only occasionally in young subjects with symptomatic hypertension and the rate of stenosis in the symptomatic hypertension group was lower, in all age groups, than in the essential hypertension group. The low prevalence of coronary stenosis in the symptomatic hypertension group may be related to the fact that fibrous plaques contained little calcium in those cases. The extent of calcified lesions in the coronary arteries was not significantly differ- ent in the symptomatic hypertension and low athero- sclerosis groups. These findings appear to account for the rare occurrence of coronary heart disease in the symptomatic hypertension group. This low fre- quency does not, however, mean that symptomatic hypertension does not accelerate the development of atherosclerosis. RESUMtI CHAPITRE 7. ATHtROSCLUROSE ET HYPERTENSION L'etude de I'atherosclerose aortique et coronarienne a ete pratiqu6e par autopsie chez 3134 sujets atteints d'hypertension essentielle. Une comparaison a ete etablie avec des groupes a degr6 faible, moyen et fort d'athero- sclerose. Les resultats montrent que l'hypertension essentielle accelere le developpement de tous les types de l6sions aortiques & 1'exception des train6es lipidiques, si on fait une comparaison avec le groupe normalise d'atheroscl6rose moyenne; elle accelere egalement le d6veloppement de la plaque fibreuse, mais non celui des lesions compliqu6es ou calcifi6es si l'on procede a une comparaison avec le groupe a fort degr6 d'athero- cl6rose. L'extension de la plaque fibreuse dans les arteres coronaires est plus grande dans le groupe d'hypertendus art6riels que dans les groupes d'ath6roscl6reux faibles ou moyens normalises, mais elle n'est pas differente de celle que l'on observe dans le groupe a fort degre d'athero- scl6rose. Le degre de lesions compliquees et calcifiees et la prevalence de la stenose coronaire sont plus elev6s dans le groupe a fort degre d'atherosclerose que dans les cas d'hypertension. Les diff6rences geographiques relev6es dans I'ath6rosclerose chez les hypertendus de differentes villes refletent les observations faites sur l'ensemble du materiel d'etude. Les hypertensions symptomatiques acce1erent l'apparition d'atherosclerose aortique au moins autant que l'hypertension essentielle. Elles provoquent l'atherosclerose des coronaires mais pas autant que l'hypertension essentielle. 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