The influence of one-year treatment by angiotensin converting enzyme inhibitor on baroreflex sensitivity and flow-mediated vasodilation of the brachial artery in essential hypertension--comparison with calcium channel blockers.

Abstract

BACKGROUND:

Both baroreflex sensitivity and flow-mediated vasodilator function have been recognized to have prognostic significance in cardiovascular diseases. Long-term antihypertensive treatment effects on these parameters, however, remain unclear.

SUBJECTS AND METHODS:

We examined the effects of long-term treatment by angiotensin converting enzyme inhibitors (ACEI) orcalcium channel blockers (CCB) on baroreflex and flow-mediated vasodilator function in patients with essential hypertension (EH). We recruited 36 patients aged 56 +/- 11 years, with systolic blood pressure > or = 160 mmHg and/or diastolic blood pressure > or = 95 mmHg. Patients were assigned either to treatment by long-acting ACEI (n = 12) or CCB (n = 24). All patients were followed for 12 months. Optimal BP was achieved by two optional increases in treatment: dose-doubling of the primary drug during the first three months and the addition of diuretics or beta-blockers thereafter. Target blood pressure was 140/90 mmHg or a fall > or = 20/10 mmHg. Baroreflex sensitivity was examined by spectral analysis of blood pressure and RR interval variabilities before treatment and after 3 and 12 months of treatment. The flow-mediated vasodilator function was determined before and 12 months after treatment by measuring the change in brachial artery diameter during increases in flow induced by reactive hyperemia.

RESULTS:

Baseline blood pressures were similar between the ACEI and CCB groups (172 +/- 5/103 +/- 2 vs. 172 +/- 4/101 +/- 3 mmHg). Blood pressures after 3 and 12 months of treatment also did not differ between the ACEI and CCB groups (149 +/- 4/91 +/- 2 vs. 145 +/- 2/85 +/- 2 mmHg, and 133 +/- 5/84 +/- 2 vs. 133 +/- 2/81 +/- 2 mmHg, respectively). Baseline baroreflex sensitivity was similar between the groups (6.7 +/- 0.8 vs. 5.9 +/- 0.6 msec/mmHg). This parameter remained unchanged at three months but increased after 12 months of treatment in both the ACEI (9.5 +/- 1.6 msec/mmHg, p = 0.05) and CCB (9.1 +/- 1.2 msec/mmHg, p = 0.006) groups. Percent increases in brachial arterial diameter and flow during reactive hyperemia increased in the group treated with ACEI (12.4 +/- 3.5 vs. 25.8 +/- 6.3% and 618 +/- 72 vs. 953 +/- 166, p < 0.05 for both) but both parameters remained unchanged in the group treated with CCB.

CONCLUSION:

These data suggest that long-term blood pressure control with modem antihypertensive drugs improves baroreflex function. Treatment with ACEI may be more favorable for flow-mediated vasodilator function than treatment with CCB.

• Authors: Masanori Munakata, Akiko Aihara, Tohru Nunokawa, Nobuhiko Ito, Yutaka Imai, Sadayoshi Ito, Kaoru Yoshinaga
• Journal: Clinical and experimental hypertension (New York, N.Y. : 1993) (Clin Exp Hypertens) Vol. 25 Issue 3 Pg. 169-81 (Apr 2003) ISSN: 1064-1963 [Print] England
• PMID: 12716079 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Angiotensin-Converting Enzyme Inhibitors
• Calcium Channel Blockers

Topics

• Aged
• Angiotensin-Converting Enzyme Inhibitors (pharmacology, therapeutic use)
• Baroreflex (drug effects)
• Brachial Artery (physiology)
• Calcium Channel Blockers (pharmacology, therapeutic use)
• Female
• Hemodynamics (drug effects)
• Humans
• Hypertension (drug therapy, physiopathology)
• Male
• Middle Aged
• Vasodilation (drug effects)