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Browsing by Author "Palma Reis, R"

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  • Good Agreement Between Echocardiography and Impedance Cardiography in the Assessment of Left Ventricular Performance in Hypertensive Patients
    Publication . Leão, R; Marques da Silva, P; Pocinho, R; Alves, M; Virella, D; Palma Reis, R
    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.
    2018Journal article Open access Show more
  • Systolic Time Ratio Measured by Impedance Cardiography Accurately Screens Left Ventricular Diastolic Dysfunction in Patients with Arterial Hypertension
    Publication . Nazário Leão, R; Marques da Silva, P; Branco, LM; Fonseca, H; Bento, B; Alves, M; Virella, D; Palma Reis, R
    BACKGROUND: The use of impedance cardiography (ICG) may play a role in the assessment of cardiac effects of hypertension (HT), especially its hemodynamic features. Hypertensive heart disease involves structural changes and alterations in left ventricular geometry that end up causing systolic and/or diastolic dysfunction. The IMPEDDANS study aims to assess the usefulness of ICG for the screening of left ventricular diastolic dysfunction (LVDD) in patients with HT. METHODS: Patients with HT were assessed by echocardiography and ICG. Receiver-operating characteristic curve and the area under the curve were used to assess the discriminative ability of the parameters obtained by ICG to identify LVDD, as diagnosed by echocardiography. RESULTS: ICG derived pre-ejection period (PEP), left ventricle ejection time (LVET), systolic time ratio (STR) and D wave were associated (p < 0.001) with LVDD diagnosis, with good discriminative ability: PEP (AUC 0.81; 95% CI 0.74-0.89), LVET (AUC 0.82; 95% CI 0.75-0.88), STR (AUC 0.97; 95% CI 0.94-1.00) and presence of D wave (AUC = 0.87; 95% CI 0.82-0.93). STR ≥ 0.30 outperformed the other parameters (sensitivity of 98.0%, specificity of 90.2%, positive predictive value of 95.2%, and negative predictive value of 96.1%). CONCLUSION: The ICG derived value of STR allows the accurate screening of LVDD in patients with HT. It might as well be used for follow up assessment. TRIAL REGISTRATION: The study protocol was retrospectively registered as IMPEDDANS on ClinicalTrials.gov (ID: NCT03209141) on July 6, 2017.
    2017Journal article Open access Show more