22 January 2010
MedWire News: Patients with hypertension who achieve greater reductions in systolic blood pressure (SBP) show improved left ventricular (LV) diastolic function relative to their peers who achieve more modest SBP reductions, study results demonstrate.
The study compared an intensive versus a standard BP lowering strategy, and although the groups showed no difference in LV function, there was a clear relationship between lower SBP and improved LV function.
“Hypertension has been associated with increased collagen deposition and cross-linking, increased interstitial fibrosis, and disturbance of calcium homeostasis in the myocardium all of which may contribute to worsening diastolic function,” say Scott Solomon (Brigham and Women’s Hospital, Boston, Massachusetts, USA) and colleagues in the journal Hypertension.
Up to 50% of patients with hypertension have diastolic dysfunction, with some researchers suggesting that it represents an important intermediate in the development of heart failure.
For the current study Solomon et al recruited 228 patients (50% women) aged an average of 59.6 years who had uncontrolled hypertension with preserved ejection fraction and diastolic dysfunction.
Half were randomized to an intensive treatment strategy, with a systolic BP target of <130 mm Hg, and the other half to a standard strategy, with a systolic BP target of <140 mm Hg. Treatment comprised a combination of valsartan, at either 160 or 320 mg, and amlodipine, at either 5 or 10 mg, with other antihypertensive medications as needed.
Echocardiographic assessment of diastolic function was performed at baseline and after 24 weeks in a prospective, open-label, blinded endpoint design.
Solomon et al report that SBP reduced significantly in both groups, from 161.2 to 130.8 mm Hg in the intensive arm and from 162.1 to 137.0 mm Hg in the standard arm, with a statistically significant difference noted between the groups.
Meanwhile myocardial relaxation velocity improved from 7.6 to 9.2 cm/s in the intensive arm and from 7.5 to 9.0 cm/s in the standard arm, indicating no difference between the two strategies.
However, after adjusting for age, baseline blood pressure, and treatment group, the degree of improvement in annular relaxation velocity was significantly and linearly associated with the extent of SBP reduction (p=0.004), with patients with the lowest achieved SBP having the highest final diastolic relaxation velocities.
Solomon et al attribute this apparent paradox to within-group reductions in SBP which overwhelmed between-group differences.
In an accompanying editorial Vittorio Palmieri (San Felice a Cancello Naples, Italy) and colleagues suggested an alternative explanation.
“A seducing hypothesis is that LV mass regression and arterial stiffness reduction in hypertension may be more relevant (or more reliable) than BP lowering as predictors of LV diastolic function improvement during treatment in arterial hypertension.”
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
Hypertension 2010; 55: 224-225