Abstract 580: Spironolactone Improves Exercise Blood Pressure but Not Functional or Myocardial Parameters in Untreated Patients With a Hypertensive Response to Exercise
Background: A hypertensive response to exercise (HRE) is associated with adverse cardiac risk, but the mechanisms remain to be clearly elucidated. Myocardial assessment by tissue Doppler imaging offers prognostic markers that reflect myocardial fibrosis and may be useful in the assessment of abnormal ventricular-vascular interaction. In this randomized, placebo-controlled study, we investigated the use of spironolactone as a possible treatment for abnormal vascular and myocardial stiffness in patients with a HRE.
Methods: We randomized 112 pts (age 55±8 years, 58% male) without a history of hypertension but who had a HRE (≥ 190/105 in women; ≥ 210/105 mmHg in men) to spironolactone 25mg daily (n= 57) or placebo (n= 55). All pts had a negative stress echo. Pts underwent evaluation at baseline and 3 months with exercise echo, VO2max, aortic pulse-wave velocity (stiffness), 24hr ambulatory BP and biochemistry. Changes in LV structure and function were assessed using early diastolic tissue velocity (Em), E/Em ratio (filling pressure), strain, strain rate and cyclical variation of integrated backscatter (CVIB).
Results: Baseline 24hr and peak exercise SBP were 134±11 mmHg and 219±17 mmHg. Baseline LV mass index (LVMI) was 87±19 g/m2 and VO2max 31.1±7.6ml/kg/m2. Differences between groups are shown in theTable⇓. Spironolactone significantly decreased exercise and 24hr SBP. There was no significant change in VO2max, LVMI, aortic stiffness, or other markers of subclinical myocardial function or fibrosis. However, in the subgroup with abnormal LVMI, treatment was associated with a significant increase in VO2max (1.8±4.9 vs −2.2±4.7ml/kg/m2, p<0.05). This was independent of change in 24hr SBP but not peak exercise SBP.
Conclusions: In untreated patients with a HRE, spironolactone reduced exercise BP but did not alter exercise capacity or markers of subclinical myocardial structure or function. However, the detection of abnormal LVMI may identify a subgroup who benefit.