Prognostic role of pulmonary impedance estimation to predict right ventricular dysfunction in pulmonary hypertension

Sara Louise Hungerford; Katherine Kearney; Ning Song; Nicole Bart; Eugene Kotlyar; Edmund Lau; Andrew Jabbour; Christopher Simon Hayward; David William Marshall Muller; Audrey Adji

doi:10.1002/ehf2.14180

Prognostic role of pulmonary impedance estimation to predict right ventricular dysfunction in pulmonary hypertension

ESC Heart Fail. 2023 Jun;10(3):1811-1821. doi: 10.1002/ehf2.14180. Epub 2023 Mar 10.

Authors

Sara Louise Hungerford^{1

2

3

4}, Katherine Kearney^{1

2

3}, Ning Song^{1

2

3}, Nicole Bart^{1

2

3}, Eugene Kotlyar¹, Edmund Lau⁵, Andrew Jabbour^{1

2

3}, Christopher Simon Hayward^{1

2

3}, David William Marshall Muller^{1

2

3}, Audrey Adji^{1

2

3

6}

Affiliations

¹ Department of Cardiology, St Vincent's Hospital, Darlinghurst, Australia.
² The University of New South Wales, Sydney, Australia.
³ Victor Chang Cardiac Research Institute, Sydney, Australia.
⁴ Department of Cardiology, Royal North Shore Hospital, Sydney, Australia.
⁵ Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, Australia.
⁶ BPVF department, Macquarie University Medical School, Sydney, Australia.

Abstract

Background: The effect of pulmonary hypertension (PH) on right ventricular (RV) afterload is commonly defined by elevation of pulmonary artery (PA) pressure or pulmonary vascular resistance (PVR). In humans however, one-third to half of the hydraulic power in the PA is contained in pulsatile components of flow. Pulmonary impedance (Zc) expresses opposition of the PA to pulsatile blood flow. We evaluate pulmonary Zc relationships according to PH classification using a cardiac magnetic resonance (CMR)/right heart catheterization (RHC) method.

Methods: Prospective study of 70 clinically indicated patients referred for same-day CMR and RHC [60 ± 16 years; 77% females, 16 mPAP <25 mmHg (PVR <240 dynes.s.cm^-5 /mPCWP <15 mmHg), 24 pre-capillary (PrecPH), 15 isolated post-capillary (IpcPH), 15 combined pre-capillary/post-capillary (CpcPH)]. CMR provided assessment of PA flow, and RHC, central PA pressure. Pulmonary Zc was expressed as the relationship of PA pressure to flow in the frequency domain (dynes.s.cm^-5 ).

Results: Baseline demographic characteristics were well matched. There was a significant difference in mPAP (P < 0.001), PVR (P = 0.001), and pulmonary Zc between mPAP<25 mmHg patients and those with PH (mPAP <25 mmHg: 47 ± 19 dynes.s.cm^-5 ; PrecPH 86 ± 20 dynes.s.cm^-5 ; IpcPH 66 ± 30 dynes.s.cm^-5 ; CpcPH 86 ± 39 dynes.s.cm^-5 ; P = 0.05). For all patients with PH, elevated mPAP was found to be associated with raised PVR (P < 0.001) but not with pulmonary Zc (P = 0.87), except for those with PrecPH (P < 0.001). Elevated pulmonary Zc was associated with reduced RVSWI, RVEF, and CO (all P < 0.05), whereas PVR and mPAP were not.

Conclusions: Raised pulmonary Zc was independent of elevated mPAP in patients with PH and more strongly predictive of maladaptive RV remodelling than PVR and mPAP. Use of this straightforward method to determine pulmonary Zc may help to better characterize pulsatile components of RV afterload in patients with PH than mPAP or PVR alone.

Keywords: Cardiac magnetic resonance imaging; Pulmonary arterial impedance; Right heart catheterization; Right ventricular-pulmonary arterial coupling.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Electric Impedance
Female
Humans
Hypertension, Pulmonary* / complications
Hypertension, Pulmonary* / diagnosis
Male
Prognosis
Prospective Studies
Ventricular Dysfunction, Right* / diagnosis
Ventricular Dysfunction, Right* / etiology