IJCS | Volume 32, Nº1, January/ February 2019

DOI: 10.5935/2359-4802.20180048 61 REVIEW ARTICLE International Journal of Cardiovascular Sciences. 2019;32(1)61-69 Mailing Address: Rodrigo Nazário Leão Av. Oscar Monteiro Torres, n 49, 1A. Postal Code: 1000-216, Areeiro, Lisbon - Portugal. E-mail: rodrigoromaoleao@gmail.com; rodrigoromaoleao@hotmail.com Impedance Cardiography in the Evaluation of Patients with Arterial Hypertension Rodrigo Nazário Leão 1, 2 and Pedro Marques Da Silva 1,3 Faculdade de Ciências Médicas, Universidade Nova de Lisboa; 1 Lisbon - Portugal Hospital de São José, Centro Hospitalar de Lisboa Central, 2 Lisbon - Portugal Hospital de Santa Marta,3 Lisbon - Portugal Manuscript received on September 27, 2017, revised on December 25, 2017, accepted on June 16, 2018. Hypertension / physiopathology; Blood Pressure; Cardiography, Impedance; Hemodynamics. Keywords Abstract Arterial hypertension is responsible for highmorbidity and mortality. Despite increasing awareness of the consequences of uncontrolled hypertension and the publication of several recommendations and guidelines, blood pressure control rates are suboptimal, and approximately half of the patients do not reach the targets. Defined as an increase in blood pressure, hypertension is characterized by hemodynamic abnormalities in cardiac output, systemic vascular resistance, or arterial compliance. Therefore, the approach to arterial hypertension can be improved by the knowledge of the hemodynamics underlying the blood pressure increase. Impedance Cardiography has emerged as a new strategy to customize therapy and monitor patients aiming to improve blood pressure control according to the hemodynamic profile, rather than a blind intensive care approach. This is a review of impedance cardiography evidence, its benefits, actual and future applications in the approach and management of arterial hypertension. Introduction Hypertension is a condition characterized by elevated blood pressure (BP). A comprehensive definition, published by the American Society of Hypertension in 2005, describes hypertension as “a progressive cardiovascular syndrome (CV) arising from complex and interrelated etiologies”. Early markers of this syndrome are often present before blood-pressure (BP) elevation occurs; thus, hypertension cannot be solely classified by discreet blood-pressure thresholds. Disease progression is strongly associated with cardiac and vascular functional and structural abnormalities that damage the heart, kidneys, brain, vasculature and other organs, leading to early morbidity and mortality. 1 It is estimated that hypertension affects approximately 1 billion individuals and causes more than 7 million deaths annually worldwide (13% of overall mortality). In Portugal, the prevalence of hypertension in the adult population aged 18 to 90 years is 42.2% (44.4% in men and 40.2% in women). 2 According to the World Health Organization (WHO), BP greater than 115 mmHg (systolic BP) is responsible for 62% of cerebrovascular diseases and 49% of ischemic cardiac pathologies, with little variation between the genders. These BP values are considered by the WHO as the main risk factor for mortality worldwide. 3,4 Although BP control is a growing concern, with a consequent increase in the number of treated and controlled patients, there is still a large percentage of treated patients who do not reach their therapeutic targets. In Portugal, only 55.6% of treated hypertensive patients have controlled BP. 2,5,6 To optimize BP control, new therapeutic strategies have been developed, namely the Plasma Renin Activity (PRA)-guided therapy, Impedance Cardiography (ICG)-guided therapy, and in some patients, renal denervation. 7-9 The choice of antihypertensive therapy based on hemodynamic systems is not new, but it has progressively become more accessible through the noninvasive hemodynamic parameters of the ICG. This is based on the knowledge that elevated BP results from changes in its hemodynamic components (cardiac output – CO, peripheral vascular resistance and/or blood volume). ICG is a non-invasive, operator-