Which method is best for an early accurate diagnosis of acute heart failure? Comparison between lung ultrasound, chest X-ray and NT pro-BNP performance: a prospective study

Abstract

Acute heart failure is a common condition among adults presenting with dyspnea in the Emergency Department (ED), still the diagnosis is challenging as objective standardized criteria are lacking. First line work-up, other then clinical findings, is nowadays made with lung ultrasound imaging study, chest X-ray study and brain natriuretic peptide (BNP) level determination; however, it is not clear which is the best diagnostic test to be used and whether there is any real benefit for clinical judgement. We set up this study to compare the performances of these three diagnostic tools; furthermore, we combined them to find the best possible approach to dyspneic patients. This is a prospective observational study based in the ED. We enrolled adults presenting with dyspnea not trauma-related, they underwent lung ultrasound, and chest X-ray studies, and NT pro-BNP level determination. Then we compared the results with the diagnosis of acute heart failure established by an independent panel of experts. 236 patients were enrolled in the study. We find sensitivity and specificity for lung ultrasound of 57.73 and 87.97 %, for chest X-ray 74.49 and 86.26 %, for NT pro-BNP 97.59 and 27.56 %, respectively. Combining together the chest X-ray and lung ultrasound, we find the best overall performance with 84.69 % sensitivity, 77.69 % specificity and 87.07 % negative predictive value. From our results, we could not identify the "best test" to diagnose acute heart failure in an emergency setting, although we could suggest that a stepwise workup combining chest X-ray and lung ultrasound at first, then for those negative, a determination of NT pro-BNP assay would be a reasonable approach to the dyspneic patient.

Diagnostic Accuracy of Point-of-Care Lung Ultrasonography and Chest Radiography in Adults With Symptoms Suggestive of Acute Decompensated Heart Failure

“…After application of the exclusion criteria, we identified 6 studies eligible for data extraction, representing a total of 1827 patients. 17 , 18 , 19 , 25 , 26 , 27 Figure 1 provides reasons for exclusion and the number of studies excluded under each reason.…”

“… 13 The number of B-lines seen on LUS has been shown to offer a semiquantitative measure of extravascular lung water content. 14 , 15 , 16 However, data on the diagnostic accuracy of LUS for cardiogenic pulmonary edema are conflicting, with reported sensitivity ranging from 57% 17 to higher than 95%. 18 , 19 Given its potential advantages over CXR, including its ease of acquisition, immediate availability of results, and evidence of comparable accuracy, LUS could have important implications for standard of care in the evaluation of patients with dyspnea at risk for ADHF.…”

Bedside Evaluation of Critical Dyspnea. Proposal of a Diagnostic Score for Acute Heart Failure in Emergency Setting

“…Figures 2A and 2B show the ROC curve of LUS estimated by evaluating the number of the B-Lines for the six zones on the right side and on the left. A high level of accuracy was exhibited in detecting AHF (AUC=82.3%; 95% CI=76.3%-87.9%); using only four scans (zone 3 to 6), instead of six, the estimated accuracy (AUC=83.3%) was not statistically different from the use of all six zones, because of a large 95% CI (77.5%-88.6%) of estimated AUC: LUS examination with only four scans seemed more convenient [13,24]. However, we preferred to consider six scans because they increased the rate of AHF patients correctly recognized only through LUS examination: further statistical analysis was made by using only six bilateral scans.…”

“…It is widely reported in literature that the ultrasound method can identify the presence of interstitial and pulmonary alveolar syndrome by noting the comet tail aspect of the artefacts, called B-lines, with high sensitivity and specificity [10][11][12][13]. This is an easy technique to perform and interpret, readily available and repeatable over time.…”

“…In a previous study, a comparison was made between lung ultrasound, chest X-ray and NT pro-BNP performance [13].…”