IJCS | Volume 33, Nº3, May / June 2020

228 (50 Hz) and the speed of shear waves propagating through the tissues is measured by ultrasound. The stiffer the hepatic parenchyma, the faster the vibrations are propagated. The waves are measured in kiloPascals (kPa), and this measure may correlate with hepatic congestion. The transducer is placed in the intercostal space at the intersection of the mid-axillary line and a transverse line at the level of the xiphoid process. The result of the elastography represents the average of all valid acquisitions and varies from 2.5 to 75 kPa. Elastography is reliable when all these criteria are met: 10 valid measurements, an interquartile range (IQR) < 30% of the average and a success rate > 60%. Two transducers are available: the standard “M” probe, used in non-obese patients, and the “XL”, used for obese patients or when the results produced by the M probe are unreliable. The reference value of elastography in healthy subjects is around 5.5 kPa with the M transducer. 7 With the aging of the population, an increase in the incidence of HF is expected. Advances in medicine and in the treatment of cardiovascular diseases will increase life expectancy, and consequently, the number of elderly individuals will also increase. 6 Thus, with the increasing trend of the prevalence of HF, there is a growing need for methods that facilitate the management of these patients, mainly because subclinical congestion is a common cause of early rehospitalization in HF. The objective of this study was to evaluate the use of elastography in the detection of hepatic congestion in patients with HF in different clinical settings, and its prognostic role in these patients. Methods A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. 10 The inclusion criteria of the studies were: articles written in English or Portuguese that included hepatic elastography in the assessment of congestion in patients with HF. Data were extracted in a standardized manner by two independent investigators, who were also responsible for evaluating themethodological quality of themanuscripts. Articles in duplicate, review studies, editorials, letters to the editor and experimental studies in animals were excluded. The search in the literature was conducted in June 2018, with no limit of publication date. Case controls, cohort studies and randomized clinical trials were searched in MEDLINE, LILACS, Scielo databases and Cochrane Database of Systematic Review. The descriptors and respective connectors used inPubMed were “elastography” [All Fields]AND “heart failure” [All Fields], with 44 articles retrieved; the descriptors used in BIREME were “elastography” AND “heart failure” AND (Collection:(“06-National/BR“OR “05-specialized“) OR db: (“LILACS“ OR “MEDLINE“) AND (Collection: (“06-National/BR“OR“05-specialized“)ORdb: (“LILACS“ OR “MEDLINE“)) AND (MJ: (“imaging techniques by Elasticity“ OR “heart failure“) AND Type_of_study: (“case_control “OR “cohort“) and limit: (“humans“) and La: (“en“), with identification of fivemore articles; and the terms used in the search inCochranewere “elastography “ AND“heart failure“, and no articles availablewere found. Then, a total of 49 articles were retrieved. The selection of the articles was made in two stages. In the first stage, two independent authors read the abstracts and those that did not fit the inclusion criteria were excluded. In the second stage, the remaining studies were read in full and, similarly, those that did not meet the inclusion criteria according to the PRISM 10 model were excluded (Figure 1). At the end, seven articles were included in the review. Results This systematic review aimed to identify the scientific evidence on the use of elastography in HF. The results showed an important correlation between liver stiffness and markers of increased venous capillary pressure. 7,10-13 In addition, liver elastography performed at hospital discharge was able to predict rehospitalization and mortality. 13 In the seven selected articles, patients were evaluated in the hospital and there was a variation in the number of study participants. The most commonly used methods for the diagnosis and evaluation of HF were echocardiography in conjunction with measurements of B-type natriuretic peptide (BNP) or N-terminal pro-B type natriuretic peptide (NT-proBNP). However, no standardization of these methods was found in most of these articles. There was a low variation in the cutoff values of elastography and some authors reported a range for normal and abnormal values (Table 1). All studies showed a correlation between increased liver stiffness and elevation of BNP or NT-ProBNP levels in the admission. 1,11,12 Colli et al. 14 observed that most patients with acute HF had liver stiffness values and NT-proBNP levels that Ávila et al. Hepatic elastography in heart failure Int J Cardiovasc Sci. 2020; 33(3):227-232 Original Article