Comparison of the effects of spironolactone and moxonidine as the fourth component of the resistant hypertension therapy on the arterial stiffness

Abstract

Objective — to compare effects of spironolactone and moxonidine as the fourth component of the treatment of resistant hypertension (RT) on the stiffness of the main arteries.
 Materials and methods. We retrospectively selected 60 patients with resistant hypertension from the database of secondary and pulmonary hypertension, treated on the basis of M. D. Strazhesko Institute of Cardiology. From them, thirty patients who received spironolactone as the fourth component to the combination of three antihypertensive drugs after not reaching the target blood pressure (BP) level, were included in group C. The rest 30 patients who received moxonidine were assigned to group M. Patients with secondary hypertension were excluded from this study. In group C, the initial spironolactone dose was 25 mg per day, and it was increased up to 50 mg per day in 6 patients. In group M, the initial moxonidine dose was 0.2 mg twice daily, it was increased up to 0.4 mg twice daily in 16 patients and up to 0.6 mg twice daily in 3 patients. Patients in both groups were administered three‑component antihypertensive therapy with maximum doses in one tablet (renin‑angiotensin system blocker + calcium antagonist + diuretic). The degree of arterial stiffness was assessed by cardio‑ancle vascular index (CAVI).
 Results. During 12 months of follow‑up, spironolactone was discontinued in 3 (10 %) patients due to the development of side effects: 1 case of gynecomastia, 1 case of hyperkalemia and one case of severe diarrhea. In group M, drug withdrawal was registered in 4 patients (13 %, the difference with group C — not significant): 2 cases of severe drowsiness, 1 case of nausea with vomiting and 1 case — dizziness without hypotension. Therefore, 27 patients from group C and 26 patients from group M were included in the final data analysis. In group C, the values of office SBP significantly decreased from 149.3 ± 6.5 to 127.4 ± 5.5 after 3 months and 124.3 ± 4.3 mm Hg after 12 months (p < 0.001, respectively). Similarly, the value of SBP in group M for 3 months was significant, but the degree of its reduction was slightly less than in group C: from 148.9 ± 7.5 to 132.5 ± 6.2 mm Hg (p < 0.05), and after 12 months — 124.3 ± 4.3 mm Hg (p < 0.001 with the initial level, and the difference between the groups is not significant). The values of DBP in group C significantly decreased from 88.8 ± 5.4 mm Hg to 75.1 ± 5.6 mm Hg at the stage of 3 months (p < 0.05), and up to 72.1 ± 4.7 mm Hg after 12 months (p < 0.001 compared to baseline). In group M at the stage of 3 months reduction of DBP from 89.1 ± 4.1 to 83.1 ± 5.1 mm Hg after 3 months (p < 0.05), and after 12 months to 73.2 ± 8.9 mm Hg (p < 0.001 compared to baseline, the difference between groups is not significant). CAVI did not change significantly in group M, with values on the right 9.4 ± 1.1 at baseline and 9.3 ± 1.3 after 12 months (p > 0.05) and on the left — 9.2 ± 1.6 and 9, 3 ± 1.6 (p > 0.05). However, the CAVI value after 12 months significantly decreased in group C from 9.5 ± 1.2 at baseline to 8.6 ± 1.2 after 12 months (p < 0.05) on the right and from 9.4 ± 1.1 to 8.7 ± 1.2 (p < 0.05), respectively, on the left in group C. In group C, LVMI decreased by 11 %: from 112.2 ± 8.4 to 101.4 ± 7.8 g/m2 (p < 0.05), while in group M we observed a tendency to reduce LVMI by 6 %, from 113.5 ± 7.7 to 107.2 ± 6.5 g/m2 (p > 0.05).
 Conclusions. Treatment with spironolactone, used as the fourth component of resistant hypertension therapy, significantly reduced the arteries stiffness as evidenced by the CAVI index, and promoted a significant regression of left ventricular hypertrophy.