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

Use of Impedance Cardiography to Guide Blood Pressure Lowering Medication Selection: Systematic Review of Randomized Controlled Trials

BACKGROUND

Blood pressure (BP) control can be difficult to attain due to multiple factors, including choosing and titrating antihypertensive medications. Measurement of hemodynamic parameters using impedance cardiography (ICG) at the point of care may allow better alignment of medication with the mechanism(s) underlying an individual's hypertension. We conducted a systematic review of randomized controlled trials of ICG compared to usual care for attainment of BP control.

METHODS

We searched Medline inclusive of the year 1946 to January 31, 2024, using a combination of MeSH terms and keywords. English-language articles were eligible for inclusion if they described results of a randomized controlled trial designed to compare ICG-guided BP-medication selection to usual care (i.e., clinician judgment/guidelines-based alone) among a sample of hypertensive patients.

RESULTS

Of 1,952 titles screened, 6 trials met inclusion criteria. The first was published in 2002 from a specialty clinic in the United States, and the most recent in 2021 from a specialty clinic in China. One trial was conducted in a primary care setting. Sample sizes ranged from 102 to 164. Participants randomized to ICG-guided antihypertensive medication had reduced BP in the short-term to a greater extent than those randomized to usual care, with odds ratios for BP control (<140/90 mm Hg) at 3 months ranging from 1.87 to 2.92. This effect was seen in both specialty clinics and in a primary care setting.

CONCLUSIONS

Incorporation of ICG in the clinical setting may facilitate medication selection that leads to a greater proportion of patients obtaining BP control in the short term.

Associations between Heart Rate Variability Parameters and Hemodynamic Profiles in Patients with Primary Arterial Hypertension, Including Antihypertensive Treatment Effects

Background: Autonomic nervous system (ANS) dysfunction is an important factor in the development and progression of arterial hypertension (AH) and may produce adverse hemodynamic sequelae. ANS function can be evaluated by analyzing heart rate variability (HRV). The purpose of this study was to assess the possible correlation between HRV and the hemodynamic profile of AH patients, including antihypertensive treatment effects after 12 months. Methods: The study was conducted on 144 patients with uncomplicated AH. The hemodynamic profile was assessed via echocardiography and impedance cardiography (ICG). The analyzed HRV parameters included SDNN, rMSSD, pNN50, low frequency (LF, 0.05–0.15 Hz), high frequency (HF, 0.15–0.4 Hz), total power (TP, the variance of all NN intervals), and the day, night, and 24-h low-to-high frequency ratios (LF/HF). Results: Analysis showed various correlations of HRV parameters both with arterial blood pressure and with the hemodynamic profile assessed via echocardiography and ICG. The HRV parameters of increased ANS activity showed a correlation with improved left ventricle function (LV) and lower LV afterload. Conclusions: Effective antihypertensive treatment demonstrated beneficial effects on both the ANS balance and the hemodynamic profile.

Hemodynamic profiles in treatment-naive arterial hypertension and their clinical implication for treatment choice: an exploratory post hoc analysis

OBJECTIVE

Noninvasive thoracic bioimpedance by the HOTMAN System estimates hemodynamic modulators and expresses them as hemodynamic profiles. Aims of this analysis were to describe hemodynamic profiles among treatment-naive hypertensive patients compared with normotensive controls and to investigate whether a hemodynamic-guided choice of therapy improves blood pressure (BP) control within 4 weeks.

METHOD

This exploratory post hoc analysis used data of a randomized parallel-group trial including 80 outpatients with newly diagnosed arterial hypertension (AHT), randomized to four antihypertensive first-line monotherapies, and 20 age-matched and sex-matched normotensive controls. Hemodynamic profiles were measured at baseline and after four weeks of treatment. On the basis of the hemodynamic profiles, the most appropriate pharmacological treatment was determined retrospectively and patients were categorised to have received concordant (ConTG) or discordant treatment (DisTG).

RESULTS

In the hypertensive group, hypervolemia with vasoconstriction was the predominant hemodynamic profile in 48% of patients and hypervolemia without vasoconstriction in 45%, compared with 15 and 50%, respectively, in the control group. After 4 weeks of treatment, the mean (±SD) 24-h BP was 129.9 (±11.0)/81.5 (±8.0) mmHg in the DisTG vs. 133.9 (±12.3)/84.0 (±9.1) mmHg in the ConTG (P = 0.158/0.222). The mean 24-h BP reductions were -9.7 (±10.1)/-5.0 (±6.2) mmHg in the DisTG and -12.4 (±14.8)/-6.9(±6.9) mmHg in the ConTG (P = 0.353/0.223). After 4 weeks of treatment, the BP control rate was 53.7% (43/80) among all, 55.7% (29/52) in the DisTG and 48% (12/25) in the ConTG (P = 0.628).

CONCLUSION

Our findings do not support the hypothesis that personalized treatment initiation based on hemodynamic profiles improves BP control in newly diagnosed hypertensive outpatients.

Clinical Use of Impedance Cardiography for Hemodynamic Assessment of Early Cardiovascular Disease and Management of Hypertension

This article is for clinicians considering impedance cardiography (ICG) for secondary prevention. ICG is an inexpensive noninvasive technology that can be used to assess hemodynamic function of the central cardiovascular system. Diverse abnormalities of ventricular function, systolic and diastolic, can be detected by ICG. Additional data pertaining to decompensation can be obtained by taking ICG readings with the patient performing postural change, from upright to supine, to quantify the compensatory response. Vascular load consists of resistive and pulsatile loads. Systemic vascular resistance can provide a measure of resistive load. Pulsatile load has two components: arterial stiffness and wave reflection. ICG can be used to calculate arterial compliance and detect aortic wave reflection. For stage 1 hypertension, a significant issue is whether a treating clinician should add pharmacotherapy to lifestyle modification. Adults who have multiple cardiovascular risk factors with stage 1 hypertension have early cardiovascular disease. ICG can be used to identify the functional abnormalities associated with the cardiovascular disease. For the management of hypertension, ICG can be used to calculate the underlying hemodynamic parameters of cardiac index and systemic vascular resistance associated with a patient's blood pressure. There can be wide ranges for cardiac index and systemic vascular resistance, with many patients having low cardiac index with high systemic vascular resistance or vice versa. These hemodynamic data can be used to customize pharmacotherapy. Drug titration can be guided by patient response to treatment using the initial hemodynamic data as a baseline for comparison to subsequent measurements from serial office visits.

Hemodynamic monitoring using thoracic bioimpedance - an optimal solution for the treatment of hypertension

Hypertension is a major issue of public health because of its increasing prevalence and multiple complications caused by failing to achieve an efficient blood pressure control. Considering hypertension as a hemodynamic disorder allows to prescribe a tailored therapy guided by individual hemodynamic parameters, therefore leading to an increased rate of control. We present the case of a 59 years old diabetic, dyslipidemic and obese male who, although treated with 5 classes of antihypertensive drugs had uncontrolled hypertension that caused left ventricular failure. Using the HOTMAN system of hemodynamic monitoring using thoracic electrical bioimpedance allowed a quick identification of the cause and guided the therapy, achieving blood pressure control after 5 days of treatment. Treating hypertension by identifying the underlying hemodynamic imbalance allows prescribing a tailored therapy and shortens the initiation and stabilization phases of treatment.

Understanding the Haemodynamics of Hypertension

PURPOSE OF REVIEW

This article introduces the haemodynamic principles that underpin the pathophysiology of hypertension and introduces a rational physiological approach to appropriate pharmacologic treatment.

RECENT FINDINGS

Outdated understanding of haemodynamics based on previous measurement systems can no longer be applied to our understanding of the circulation. We question the current view of hypertension as defined by a predominantly systolic blood pressure and introduce the concept of vasogenic, cardiogenic and mixed-origin hypertension. We postulate that failure to identify the individual's haemodynamic pattern may lead to the use of inappropriate medication, which in turn may be a major factor in patient non-compliance with therapeutic strategies. A population-based approach to treatment of hypertension may lead to suboptimal functional dynamics in the individual patient. Finally, we question the validity of current guidelines and published evidence relating morbidity and mortality to the future treatment of hypertension. The importance of individual haemodynamic profiles may be pivotal in the understanding, diagnosis and treatment of hypertension if optimal control with minimal adverse effects is to be achieved. Research based on individual haemodynamic patterns is overdue.

Good agreement between echocardiography and impedance cardiography in the assessment of left ventricular performance in hypertensive patients

BACKGROUND

Impedance cardiography (ICG) is a noninvasive hemodynamic monitoring tool which can define hypertensive patients' hemodynamic profiles and help to tailor antihypertensive therapy. This study assesses the concordance between ICG-derived indexes used to evaluate left ventricular performance and transthoracic echocardiography (TTE) in hypertensive patients.

METHODS

In this IMPEDDANS post-hoc analysis, the ICG-derived indexes are compared with TTE by Bland-Altman method. Statistical significance of the relationship between the values obtained was assessed by generalized linear mixed-effects models.

RESULTS

In supine position, Bland-Altman analysis showed good concordance for cardiac output (CO) (mean difference of 0.006 mL/min [-0.120; 0.133]), cardiac index (CI) (mean difference of 0.016 mL/min/m² [-0.471; 0.504]), pre-ejection period (PEP) (mean difference of -0.216 ms [-4.510; 4.077]), left ventricular ejection time (LVET) (mean difference of -0.140 ms [-6.573; 6.293]), and systolic time ratio (STR) (mean difference of -0.00004 [-0.008; 0.008]). In orthostatic position, good concordance was found for CO (mean difference 0.028 mL/min [-2.036; 1.980]), CI (mean difference -0.012 mL/min/m² [-1.063; 1.039]), and STR (mean difference -0.101 [0.296; 0.094]). No significant difference between methods was identified by the linear mixed-effects models.

CONCLUSION

The ICG-derived indexes CO, CI, PEP, LVET, and STR in supine position have good agreement with TTE. Therefore, ICG can be used to accurately evaluate left ventricular performance.