Tesi di specializzazione (5 anni)
Effects of spironolactone and inorganic nitrate as beetroot juice on cardiac structure and performance in patients at risk of or with type 2 diabetes
MEDICINA CLINICA E SPERIMENTALE
Corso di studi
relatore Prof. Taddei, Stefano
- cardiac structure
Data inizio appello
Data di rilascio
Patients with type II diabetes (T2DM) are at 2-3 fold excess risk of heart failure. Its prevention and treatment are poor. Here we tested the hypothesis that spironolactone, perhaps by limiting myocardial fibrosis, and inorganic nitrate, which acutely affects myocardial dynamics, would improve cardiac structure and function beyond effects of blood pressure (BP) in these patients.<br>105 patients with or at risk of T2DM participated in a factorial design, double blind, randomised controlled trial (VaSera). Trans-thoracic cardiac ultrasound (echo) was performed at randomisation, 3 and 6 months after intervention of either ≤50 mg spironolactone or ≤16 mg doxazosin (control), and beetroot juice (≤11 mmol inorganic nitrate (NO3-)) or placebo (NO3- depleted). Data are ‘intention-to-treat’.<br>Brachial BP change was similar between drugs (spiro/dox ΔSBP 6.5/6.4 mmHg ΔDBP 5.2/4.8 mmHg) unaffected by juice. Reduction in LVMI with spironolactone tended to be greater than doxazosin’s (mean (95% CI): -1.48 (-2.08,-0.88) vs -0.63 (-1.28,0.01) g/m2.7, p=0.064), but with overtly significant effects on mean differences in LV posterior wall (-0.3 (-0.4,-0.1) mm, p<0.01) and relative wall thickness (-0.01 (-0.02,-0.0), p<0.01). ΔE/A ratio on spironolactone decreased by 0.12 (-0.19,-0.04) (p<0.01) compared with doxazosin while ΔS’ (a tissue Doppler index of systolic function) increased compared with doxazosin by 0.52 (0.05,1) cm/s, p<0.05. No treatment altered the E/E’ ratio.<br>While NO3- did not affect the above parameters, active juice decreased LV end diastolic (ED) and systolic volume (6.3 (-11.1,-1.6) mL and 3.2 (-5.9,-0.5) mL, p=0.01 and p=0.02 respectively) and increased the ED mass/volume (M/V) ratio by 0.04 (0,0.7) g/mL (p<0.05) compared to placebo.<br>In conclusion, spironolactone influences myocardial remodelling and LV systo-diastolic function in patients with or at risk of T2DM. Inorganic nitrate decreases LV volumes with no changes in LV mass, which leads to increased M/V ratio suggesting a favourable effect on LV wall stress. The VaSera trial was funded by Fukuda Denshi.
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