Table 1.

Characteristics of the included studies

Study; country; no. of sites	Funding	Design	Cohort	n	Age, years, mean	US protocola	Scanning interval	Mortality	Readmission	LOS	Changes in IVC-CI and B-lines
Studies with US of the IVC
Asahi et al. 2016 [11] Japan, 1 site	NR	Pre–post	AHF, chronic HF	74	75	Probe NR Mode NR Meas. point NR	Admission, 24 h	NR	NR	NR	72–52% if 1st IVC-CI ≥ 0.5, 28–43% if 1st IVC-CI < 0.5
Chuen et al. 2009 [22] UK, 1 site	NR	Pre–post	AHF	31	72	Probe NR M-mode Measurement point NR	0, 0.5, 1, 2, 3 h	NR	NR	NR	ICV-CI 12–14%
Cubo-Romano et al. 2016 [23] Spain, 1 site	Grants for a medical society in Spain and National Institutes of Health	Pre–post	AHF	97	78	Convex Mode NR 2 cm from RA	< 24 h, discharge	90 days mortality rate 25.4% if IVCmax ≥ 1.9 cm vs. 3.4% 180 days: 29.3% vs. 3.4%	90 days readmission rate 30.8% if IVCmax ≥ 1.9 cm vs. 10.7% 180 days, 38.0% vs. 14.3%	NR	IVC-CI 25.7–33.1%
DeVecchis et al. 2012 [41] Italy, 2 sites	NR	Retrospective	AHF	49 34 controls	77	Sector M-mode 3 cm from RA	Admission, < 48 h	NR	NR	NR	IVC-CI 28.2–30.0%
Fawzi et al. 2012 [24] Egypt, sites NR	NR	Pre–post	AHF	30	50	NR	Admission, day 5, day 10	NR	NR	NR	NRb
Goonewardena et al. 2008 [25] USA, 1 site	NR	Pre–post	AHF	75	61	Probe NR Mode NR 3 cm from RA	< 12 h, discharge	NR	30 days: 41% readmitted IVC-CI, at admission was 23% in those readmitted vs. 31% in those not readmitted At discharge 36% vs. 57%	NR	IVC-CI 27–45%
Guiotto et al. 2010 [26] Italy, 1 site	NR	Pre–post	AHF	24	72	Sector M-mode 3 cm from RA	Before, after 12 h and at the end of ultrafiltration	NR	NR	NR	IVC-CI 12.5–23.6%
Patnaik et al. 2016, USA [27] USA, 1 site	NR	Pre–post	AHF	50	68	NR	< 24 h, daily	NR	NR	No difference in LOS according to IVC-CI	IVC-CI 41.3–40.9%
Tchernodrinski et al. 2014 [28] USA, 1 site	None	Pre–post	AHF	70	55	Sector Mode NR 2 cm from RA	0.5 h before, 1–2 h, 2–3 h after i.v. furosemid	NR	NR	NR	IVCmax 2.3–0.21 cm
Yavasi et al. 2014 [12] Turkey, 1 site	NR	NRCT	AHF	47 50 controls	67	Conex Mode NR Distal to hepatic vein	Before + after 12 h of Tx	NR	NR	NR	IVC-CI: 22.80–39.75% Controls: no difference in IVC-CI
Studies with LUS
Cortellaro et al. 2017 [29] Italy, 4 sites	NR	Pre–post	AHF	41	77	Convex Transverse/oblique orient 11 zonesc	Admission, + 3, + 24 h	NR	NR	NR	B-score: 1.59–0.38 points
Daskalov et al. 2016 [30] Bulgaria, 1 site	NR	Pre–post	AHF	100	NR	NR	Admission, 4 ± 2 days	NR	NR	NR	Reduction in B-lines, exact numbers NR
Facchini et al. 2016 [31] Italy, sites NR	NR	Pre–post	AHF	50	75	Probe NR Orient. NR 28 zones Sum B-lines	Admission, 24 h	NR	NR	NR	B-lines: 53.4–31.7
Gargani et al. 2015 [32] Italy, 1 site	One coauthor was consultant for several medical indutries	Pre–post	AHF	118	70	Probe NR Orient. NR 28 zones Sum B-lines	Admission, discharge	4 died, B-lines relation NR	14 readmitted with more B-lines at admission + discharge	NR	B-lines: 48–20
Martindale et al. 2018 [33] USA, 2 sites	Supported in part by grants from a university and National Institutes of Health	Pre–post	Dyspnea, sBT ≥ 180 mmHg, AHF	20	68	Convex Sagittal orient 8 zones Sum B-lines	< 45 min, after improvement of dyspnea, discharge	NR	NR	NR	B-lines: 47–8 Correlation between dyspnea (VAS from 0 to 10) and no. of B-lines
Palazzuoli et al. 2018 [34] Italy, 1 site	One coauthor received grants from medical industry	Pre–post	AHF	162	80	Probe NR Orient. NR 8 zones Sum B-lines	< 12 h, discharge	10% died, had a higher B-line count at discharge	28% readmitted, had a higher B-line count at discharge	NR	B-lines: 31–20 B-lines had a correlation with RR
Platz et al. 2019 [35] USA, 2 sites	Supported by grants from National Institutes of Health, the British Heart Foundation and several medical indutries	Pre–post	AHF	349	75	Sector Sagittal orient 4 zones Sum B-lines	< 4 days, discharge	6 months, 36% (0–4 B-lines at discharge) vs. 55% (> 7 B-lines) died/readmitted	6 month, 36% (0–4 B-lines at discharge) vs. 55% (> 7 B-lines) died/readmitted	0–3 B-lines: 5 days 4–6 B-lines: 8 days ≥ 7 B-lines: 7 days	B-lines: 6–4
Strnad et al. 2016 [13] Slovenia, 1 site	NR	RCT	AHF	20	81	Micro convex Orient. NR 15 zones Sum B-lines	NR	CPAP: 58% survied to discharge Control: 75% survied to discharge	NR	CPAP: 13 days Control: 7 days	B-lines: CPAP group, 46.9–29.0 Control, 42.4–43.3
Vitturi et al. 2011 [36] Italy, 1 site	NR	Pre–post	Dyspnea	152	NR	Convex Sagittal orient Zones NR Pos. scan: > 8 B-lines	Admission, 48 h	NR	NR	NR	B-lines decreased, exact no. NR
Volpicelli et al. 2008 [37] Italy, 1 site	NR	Pre–post	AHF	81	75	Convex Sagittal orient 15 zones Sum B-lines	Admission, discharge	NR	NR	NR	B-lines: 8 positive zones to 0
Studies with both US of the IVC and LUS
Mozzini et al. 2018 [40] Italy, 1 site	NR	RCT	AHF	LUS: 60 CXR: 60	84	LUS: sector Orient. NR Zones NR Sum of B-lines IVC: convex M-mode 2 cm from RA	LUS: admission, 24 h, 48 h, 72 h, discharge IVC: admission, discharge	NR	NR	LUS group: 7 days CXR group: 8 days	B-lines from 23 to 50% IVC-CI: Inverse association between IVC-CI and no. of B-lines
Spevack et al. 2017 [15] Canada, sites NR	None	Pre–post	AHF	50	77	LUS: convex Oblique orient 8 zones Sum of B-lines IVC: sector mode NR 1–2 cm from RA	Admission, 1 day, discharge	NR	NR	NR	IVC-CI 30–25% B-lines: 11–8.3
Öhman et al. 2018 [39] Finland, 1 site	NR	NRCT	AHF	US-guided Tx: 20 Control: 100	76	LUS: sector Sagittal orient 6 zones Sum B-linesd IVC: sector M- or B-mode 1–2 cm from hepatic vein	Admission, daily, discharge	84% patients with resolution of congestion survied at 6 months vs. 61%	36% patients with resolution of congestion died/readmitted vs. 58% at 6 months	NR	Congestion decreased but no. of B-lines NRe
Öhman et al. 2018 [38] Finland, 1 site	None	Pre–post	AHF	60	76	LUS: sector Sagittal orient 6 zones Sum B-linesd IVC: sector M- or B-mode 1–2 cm from hepatic vein	0 h, 12 h, 24 h, 48 h, discharge	84% patients with resolution of congestion survied at 6 months vs. 60%	37% patients with resolution of congestion died/readmitted vs. 64% at 6 months	Resolution: 6.16 days Congestion: 7.22 days	Congestion decreased but no. of B-lines NRe

AHF acute heart failure, CPAP continuous positive airway pressure, CXR chest X-ray, HF heart failure, IVC-CI inferior vena cava-collapsibility index, IVCmax inferior vena cava max diameter, LOS length of stay, LUS lung ultrasound, NR not reported, NRCT non-randomized controlled trial, orient. orientation, RA right atrium, RCT randomized controlled trial, RR respiratory rate, sBT systolic blood pressure, Tx treatment, US ultrasound, VAS visual analog scale

^aProbe type, M- or B-mode (IVC), orientation of the probe (LUS), no. of scanning zones (LUS)

^bDiscrepancy between reported IVC-CI in text and table and therefore NR

^cScore: 0 points: < 3 B-lines in a zone, 1 point: ≥ 3 B-lines in ≥ 1 zone, 2 points: multiple B-lines

^dCongestion definition: 3 ≥ B-lines in ≥ 1 zone bilat. or > 5 mm of pleural fluid bilaterally

^eIVC is reported as a categorical scaled IVC index