[Neural control of the peripheral circulation and blood pressure]

In the XIX century Claude Bernard discovered the action of the nervous system on the peripheral circulation. In the first half of the XX century Ewald Hering discovered the baro-receptor and the reflex control of the heart rate and blood pressure. Cowley and Guyton demonstrated that sino-aortic denervation induces persistent changes in the blood pressure in the dog. The autonomic nervous system is mainly responsible for the regulation of the circulation and blood pressure in the short term on a beat to beat basis. It controls the vasomotor tone, the heart rate and the cardiac output. With the advent of non invasive methods that measure the blood pressure on a beat to beat basis (Finapres) and with the methods of measurement of the variability of the blood pressure in the frequency domain (spectral analysis) we can currently measure many variables including heart rate, blood pressure, stroke volume, peripheral resistances and the baroreceptor sensitivity and make some inferences about their control mechanisms. These variables can be measured at rest in the supine position, standing up, during rhythmic breathing and during the Valsalva maneuver. In this article we present a review of the neural control of the blood pressure and heart rate.

Mechanical factors of cardiovascular risk in systemic arterial hypertension. A new sign of arterial rigidity

ANTECEDENT: By means of sphygmokinetocardiography (SKCG) we developed and arterial rigidity index (ARI) which measure the pulse wave aortic carotid reflexion time over the left ventricular ejection time (LVET). This index, together with the pulse wave velocity (PWV) and the pulse pressure (PP) are indicators of arterial stiffness. In this paper we measured these index in 27 systemic artery hypertension. Cases (group A, GA), with and without left ventricular hypertrophy (subgroups: A1 SGA1, n = 13, and A2, SGA2, n = 14), respectively, and 28 normotensive cases (group B, GB).

PROTOCOL

In two occasions: after 3 minutes of sitting position (SP) and after 3 minute of logging in an upright position (UP), blood pressure, ARI, PP, PWV (aortic-hand finger distance/aorto-hand finger pulse time) and R-IV interval (electrocardiographic R wave-left early ventricular kinetocardiography deflexion) were measured.

RESULTS

Demography was similar in GA and GB. Systolic, diastolic and pulse pressure were significantly higher in GA vs GB. LVET (ms) was lower in GA vs GB in SP (268 +/- 42 vs 274 +/- 40, p < 0.001, respectively) and higher postexercise UP (280 +/- 42 vs 244 +/- 46, p < 0.001). PWV m/s were higher in SP in GA vs GB (9.8 +/- 2.8 vs 7.4 +/- 1.2, p < 0.001, respectively) and in UP (10.1 +/- 1.9 vs 7.9 +/- 9, p < 0.001, respectively). ARI was lower in UP in GA vs GB (0.48 +/- 0.3 vs 0.80 +/- 0.3, p < 0.003). Correlation index of PP vs SBP, vs DBP and vs PWV were significant in SP and in UP. Height had a significant correlation vs ARI in SP and UP (r = 0.60, p < 0.01, and r = 0.42, p < 0.05, respectively).

CONCLUSION

PWV is increased in GA vs GB patients. The ARI index is lower in GA vs GB cases in post exercise. PWV and PP showed a statistical significant correlation; height vs ARI had also a significant correlation: SKCG is a new method, that uses a not commercially instrument, which should have clinical application.

[A system for non-invasive measurement of arterial pulse velocity in different vascular territories]

Blood pulse wave velocity (PWV) is a known index of arterial rigidity and its measurement has proved its usefulness in the study of some cardiovascular pathologies. In this study we describe the design and implementation of a system for noninvasive PWV determination in the aorto-braqui-humero-radial (A-->h), aorto-ileo-femoro-pedial (A-->f) and aorto-carotid (A-->c) regions. This system was examined with 36 normotensives (NT) and 34 hypertensives (HT) patients with (LVH, n = 20) and without (WLVH, n = 14) left ventricular hypertrofy. The equipment consist of a personal computer with an analog to digital converter and hardware and software items adapted to take simultaneously the electrocardiogram (ECG), two photopletismographic pulses and one oscilometric pulse. The Q-pP interval (time between a Q ECG wave and distal blood pulse) and the distance to the register sites are taken into account to calculate the beginning of cardiac prexpulsive period (time zero of pulse trip) which allow the determination of the PWV (in meters/second) from the aortic root to the distal point of the via. PWV was significant higher (p < 0.001) in HT vs. NT (A-->h: 9.3 +/- 2.6 vs. 7.2 +/- 0.8, A-->c: 9.5 +/- 2.8 vs. 6.0 +/- 1.9 and A-->f: 9.5 +/- 1.8 vs. 7.2 +/- 0.9) in each evaluated arterial region. Same thing occurred in cases with LVH vs. WLVH (A-->h: 10.5 +/- 1.6 vs. 8.0 +/- 1.9, A-->c: 10.2 +/- 1.9 vs. 8.0 +/- 1.9 and A-->f: 10.5 +/- 2.0 vs. 8.6 +/- 1.2) (p < 0.025). This is consistent with the relationship more pressure [symbol: see text] more rigidity and with other reports. This method may have clinical application.

Immunologic studies in patients with Takayasu's arteritis. II. Effects of serum on lymphocyte functions in vitro

Natural lymphocytotoxic antibodies, circulating immune complexes and their effect on in vitro blast transformation of normal cells were studied in 24 patients with Takayasu's arteritis. Sera with Takayasu's arteritis lacked lymphocytotoxic antibodies, had an inhibitory effect on the formation of EA and EAC rosettes and interfered with normal lymphocyte function in vitro. The absence of lymphocytotoxic antibodies, together with the other epidemiological and histocompatibility studies, would support the notion that Takayasu's arteritis and temporal arteritis are two distinct entities.

Takayasu's arteritis. Clinical study of 107 cases

The clinical experience derived from the retrospective study of 107 cases of TA over a 19 year period is presented. The disease predominated in females (8.5:1), with age of onset usually less than 20 years. In half of the cases an acute inflammatory phase was observed, characterized mainly by systemic and cardiovascular symptoms. Subsequently the natural course of TA was toward chronicity with gradual deterioration. The most frequent variety of TA (65 per cent of the patients) was Type III, in which the supra-aortic trunks and the abdominal aorta were involved. The predominant clinical features were reduction of amplitude of peripheral arterial pulses (96 per cent), vascular bruits (94 per cent), and raised blood pressure (72 per cent), mainly resulting from renal arterial involvement (62 per cent). Heart failure (28 per cent) is rarely the result of direct coronary arteritis. TA is most often confused with aortic coarctation, but usually the aortogram distinguishes these. The etiology of TA is discussed. The high incidence of previous and present active tuberculous (48 per cent) in the present series and previous experimental work suggest that tuberculosis may play an important role in the etiology of TA. Treatment for antihypertension and heart failure should be employed when indicated. Treatment with corticosteroids requires further evaluation. Treatment for tuberculosis is not justified in all cases until the exact role of tuberculosis is well established.

[Double-blind therapeutic trial of spironolactone in arterial hypertension]

Spironolactone is a diuretic, selective aldosterone, antagonist with its own antihypertensive action which prevents body loss of potassium. Its clinical use has been documented on the treatment of essential arterial hypertension; however, there does not seem to be enough information to form a solid chemical criterion. This work is a clinical evaluation of the antihypertensive effect of the drug using double-blind technic with 41 patients with essential arterial hypertension, all external patients from the Instituto de Cardiología. They were divided in two groups, selected at random, to be able to observe their tensional range with spironolactone every two weeks, during 16 weeks; and using a placebo for the next 16 weeks. On group following this order; and the other one viceversa. After 32 weeks, the results observed show the effect of placebo, as well as spironolactone on arterial pressure and the statistic comparison, states the real antihypertensive effect of the drug on this group of patients. Every day doses were from 300 to 450 mg., and with it there was a rise in seric potassium of an average of 1 mEq/l. The authors suggest that this drug is useful in cases of essential hypertension although its pathway isn't deeply known. Apparently, the antihypertensive effect of spironolactone is not solely on patients with hypertension due to primary aldosteronism. The intervention on various hipertensinogenous factors in relation to its effect are discussed.