Who benefits more from hemodynamically guided hypotensive therapy? The experience from two randomized, prospective and controlled trials

Abstract

Objectives: Arterial hypertension (AH) may be related to fluid retention, increased vascular resistance or hyperdynamic heart function. Impedance cardiography (ICG) is shown to be useful in the individualization of antihypertensive therapy but little is known about who most benefits from this therapeutic approach. The aim of this analysis was to estimate the effectiveness of ICG-guided antihypertensive therapy with respect to baseline blood pressure (BP) from the perspective of 12 weeks' observation in randomized, prospective and controlled trials.

Methods: This analysis involved 272 patients (average age: 44.1 ± 10.8 years) with AH. After baseline evaluation, including: office BP measurement (systolic, SBP; diastolic, DBP; mean, MBP) and ambulatory BP monitoring (mean 24-h SBP, mean 24-h DBP) the subjects were randomly assigned to groups of empiric [GE] and ICG-guided antihypertensive therapy [HD]. The results were evaluated separately in subgroups derived from median of MBP (110 mmHg): with slightly increased ('SI_BP') and more increased BP ('MI_BP'). The comparative analysis included absolute change in BP (d_OSBP, d_ODBP, d_24-h SBP, d_24-h DBP) and the percentage of patients with reduction of BP ⩾ 10 mmHg (d10_OSBP, d10_ODBP, d10_24-h SBP, d10_24-h DBP).

Results: ICG-guided therapy was shown to be superior to the empiric approach, especially in MI_BP. In this subgroup, the BP reduction in HD was higher than in GE: d_OSBP (23.3 ± 10.8 versus 18.5 ± 13.9 mmHg; p = 0.035), d_ODBP (16.0 ± 6.3 versus 11.6 ± 9.6 mmHg; p = 0.003), d_24-h SBP (17.7 ± 10.8 versus 13.1 ± 13.1 mmHg; p = 0.035). This benefit was also confirmed by a higher percentage of patients with significant BP reduction: d10_OSBP (87.7% versus 69.1%; p = 0.012), d10_ODBP (69.2% versus 47.3%; p = 0.012) and d10_24-h SBP (72.3% versus 52.7%; p = 0.012). The comparison in the SI_BP subgroup did not reveal such significant differences.

Conclusions: The hemodynamically guided pharmacotherapy results in greater BP reduction. This effect is more pronounced in patients with higher baseline BP, while in those with slightly increased BP the empiric approach seems comparable to ICG.

Keywords: antihypertensive agents; blood pressure; cardiovascular diseases; hemodynamics; hypertension; impedance cardiography.