[Role of nitrates in pharmacologic modulation of reflected waves and their significance in the treatment of arterial hypertension in the elderly].

OBJECTIVE

To analyse the efficacy of a sustained release form of isosorbide mononitrate in the treatment of isolated systolic hypertension in the elderly.

PATIENTS

24 patients suffering from essential hypertension and with an average age of 68.5 +/- 1.1 years were studied: 20 male and four female patients, all with isolated systolic hypertension (systolic blood pressure (SBP) > 160 mmHg and diastolic blood pressure (DBP) < 90 mmHg). None of the patients had received pharmacological treatment for their hypertension. None were receiving other medication or displayed concomitant pathologies.

METHODS

Assessment of all the patients was made with the measurement of their occasional blood pressure, ambulatory measurement of blood pressure and the measurement of pulse wave velocity in two arterial zones (carotid-femural) by mecanography before and after thirty days of monotherapy with a single 50 mg dose of a sustained release form of isosorbide mononitrate. Four patients were withdrawn from tests due to signs of intolerance to the drug.

RESULTS

A fall in occasional blood pressure was recorded, with statistical significance in relation to SBP only: SBP-192 +/- 15.5-->164 +/- 10.2 mm Hg (p < 0.001); DBP-85 +/- 4.2-->83 +/- 5.4 mm Hg. Ambulatory blood pressure readings also showed a significant drop in average SBP readings over the 24 hours: SAP 152.6 +/- 13.6-->140.5 +/- 15.4 mm Hg (p < 0.03); DBP 77.2 +/- 8.7-->72.3 +/- 5.47 mm Hg. No significant changes in pulse wave velocity were recorded for the zones studied: carotid-femural -20.8 +/- 6.0-->21.7 +/- 5.1 m/sec; femural-foot -4.5 +/ -1.4-->4.4 +/- 2.6 m/sec; a marked alteration in the morphology of arterial pulse in the aortic zone was observed, however, with a clear levelling off and reduction of the systolic peak.

CONCLUSION

Treatment with nitrates may be a new and effective alternative for the treatment of the age group in question. It acts specifically on the pathophysiological mechanisms of isolated systolic arterial hypertension in the elderly. Changes in reflected wave velocity (retrogrades) seem to cause the significant reduction in SBP, observed in this group of patients.