J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website http://www.jocmr.org

Review

Volume 8, Number 8, August 2016, pages 569-574

Estimating Right Atrial Pressure Using Ultrasounds: An Old Issue Revisited With New Methods

Figure 1. (A) Representation of the IVC collapsibility index (IVCCI) and (B) IVCCI measurement using M-mode ultrasonography. (A) IVCCI consists of the difference between the end-expiratory (IVCd-exp) and end-inspiratory (IVCd-insp) divided by IVCd-exp. (B) Based on the measurements in this example, the IVCCI would be (18.3 - 3.8 mm)/18.3 mm, or 79.2%.

Figure 2. B-mode and M-mode views of the subclavian vein (SCV) with expiratory and inspiratory diameters measured. The clavicle is visualized anterior (above) the subclavian artery at the left side of the top image (superior to the SVC). Again, consistent with our approach to the IVCCI, we utilized minimal (inspiratory) and maximal (expiratory) diameters of the SCV. For further explanations, please see the text.

**Table 1.** Hemodynamic Monitoring With a Pulmonary Artery Catheter: Normal Pressures and Resistance Values
	Mean	Range
Right atrium	4 mm Hg	1 - 8 mm Hg
Right ventricle
Peak-systolic	25 mm Hg	15 - 30 mm Hg
End-diastolic	9 mm Hg	4 - 12 mm Hg
Pulmonary capillary wedge pressure	9 mm Hg	4 - 12 mm Hg
Systemic vascular resistance	1,100 dyne-s/cm⁵	700 - 1,600 dyne-s/cm⁵
Pulmonary vascular resistance	70 dyne-s/cm⁵	20 - 130 dyne-s/cm⁵

Table 1. Hemodynamic Monitoring With a Pulmonary Artery Catheter: Normal Pressures and Resistance Values

Mean

Range

Right atrium

4 mm Hg

1 - 8 mm Hg

Right ventricle

Peak-systolic

25 mm Hg

15 - 30 mm Hg

End-diastolic

9 mm Hg

4 - 12 mm Hg

Pulmonary capillary wedge pressure

9 mm Hg

4 - 12 mm Hg

Systemic vascular resistance

1,100 dyne-s/cm⁵

700 - 1,600 dyne-s/cm⁵

Pulmonary vascular resistance

70 dyne-s/cm⁵

20 - 130 dyne-s/cm⁵

**Table 2.** Estimation of RA Pressure on the Basis of IVC Diameter and Collapse According to Rudski et al [19]
Variables	Normal (0 - 5(3) mm Hg)	Intermediate (5 - 10(8) mm Hg)	High (15 mm Hg)
Ranges are provided for low and intermediate categories, but for simplicity, midrange values of 3 mm Hg for normal and 8 mm Hg for intermediate are suggested. Intermediate (8 mm Hg) RAPs may be downgraded to normal (3 mm Hg) if no secondary indices of elevated RAP are present, upgraded to high if minimal collapse with sniff (< 35%) and secondary indices of elevated RAP are present, or left at 8 mm Hg if uncertain. IVC: inferior vena cava; RAP: right atrial pressure. The table synthetically displays the concepts expressed by Rudski et al [19] in the official recommendations of the American Society of Echocardiography (2010). These criteria have been left unchanged in the recent update [20] (January 2015).
IVC diameter	≤ 21 mm	≤ 21 mm; > 21 mm	> 21 mm
Collapse with sniff	> 50%	< 50%; > 50%	< 50%
Secondary indices of elevated RAP			Restrictive filling Tricuspid E/e’ > 6 Diastolic flow predominance in hepatic veins (systolic filling fraction < 55%)

Table 2. Estimation of RA Pressure on the Basis of IVC Diameter and Collapse According to Rudski et al [19]

Variables

Normal (0 - 5(3) mm Hg)

Intermediate (5 - 10(8) mm Hg)

High (15 mm Hg)

Ranges are provided for low and intermediate categories, but for simplicity, midrange values of 3 mm Hg for normal and 8 mm Hg for intermediate are suggested. Intermediate (8 mm Hg) RAPs may be downgraded to normal (3 mm Hg) if no secondary indices of elevated RAP are present, upgraded to high if minimal collapse with sniff (< 35%) and secondary indices of elevated RAP are present, or left at 8 mm Hg if uncertain. IVC: inferior vena cava; RAP: right atrial pressure. The table synthetically displays the concepts expressed by Rudski et al [19] in the official recommendations of the American Society of Echocardiography (2010). These criteria have been left unchanged in the recent update [20] (January 2015).

IVC diameter

≤ 21 mm

≤ 21 mm; > 21 mm

> 21 mm

Collapse with sniff

> 50%

< 50%; > 50%

< 50%

Secondary indices of elevated RAP

Restrictive filling
Tricuspid E/e’ > 6
Diastolic flow predominance in hepatic veins (systolic filling fraction < 55%)

**Table 3.** Accuracy, Sensitivity and Specificity of Echocardiographic Measurements for Identification of RAP > 10 mm Hg According to Patel et al [21]
	3D-RAVi ≥ 35 mL/m² + IVC ≥ 2 cm	3D-RAVi ≥ 35 mL/m²	3D-RAVi ≥ 35 mL/m² + IVC ≥ 2 cm + IVCCI < 40%	IVC ≥ 2 cm	IVC ≥ 2 cm + IVCCI < 40%
Comparison of 3D-RAVi ≥ 35 mL/m² + IVC ≥ 2 cm versus IVC parameters alone. *P = 0.038 versus IVC ≥ 2 cm + IVCCI < 40%; †P = 0.041 vs. IVC ≥ 2 cm + IVCCI < 40%. RAP: right atrial pressure; 3D-RAVi: three-dimensional right atrial volume index; IVC: inferior vena cava expiratory diameter; IVCCI: inferior vena cava collapsibility index.
Accuracy	0.88*	0.85	0.70	0.83	0.68
Sensitivity	0.86†	0.89	0.57	0.89	0.60
Specificity	0.92	0.75	1.00	0.67	0.83

Table 3. Accuracy, Sensitivity and Specificity of Echocardiographic Measurements for Identification of RAP > 10 mm Hg According to Patel et al [21]

3D-RAVi ≥ 35 mL/m² + IVC ≥ 2 cm

3D-RAVi ≥ 35 mL/m²

3D-RAVi ≥ 35 mL/m² + IVC ≥ 2 cm + IVCCI < 40%

IVC ≥ 2 cm

IVC ≥ 2 cm + IVCCI < 40%

Comparison of 3D-RAVi ≥ 35 mL/m² + IVC ≥ 2 cm versus IVC parameters alone. *P = 0.038 versus IVC ≥ 2 cm + IVCCI < 40%; †P = 0.041 vs. IVC ≥ 2 cm + IVCCI < 40%. RAP: right atrial pressure; 3D-RAVi: three-dimensional right atrial volume index; IVC: inferior vena cava expiratory diameter; IVCCI: inferior vena cava collapsibility index.

Accuracy

0.88*

0.85

0.70

0.83

0.68

Sensitivity

0.86†

0.89

0.57

0.89

0.60

Specificity

0.92

0.75

1.00

0.67

0.83