Assessment of Right Ventricular Afterload in COPD

Figures & data

Figure 1. Tracing (dotted line) of right ventricular velocity time integral (RVSmVTI) from tissue Doppler obtained from the lateral tricuspid annulus.

Table 1. Baseline characteristics of study participants

Variables (unit)	COPD (n = 100)
Demographics
Age (years)	63 ± 7
Sex Female/Male (n)	51/49
Body mass index (kg/m^2)	25 ± 5
Body surface area (m^2)	1.8 ± 0.3
Caucasian (%)	100
GOLD stages I-IV (n)	2/37/31/30
Smoking habits^§ (n)	69/31/0
Pack-years of smoking	40 ± 19
Sinus rhythm (%)	100
Atrial arrhythmia (%)	0
Pulmonary function
FEV1/FVC (%)	48 ± 12
FEV1% predicted	43 ± 16
RV % predicted	207 ± 63
DLCO % predicted	53 ± 22
Arterial blood gases
PaO2 (kPa)	9.4 ± 1.5
PaCO2 (kPa)	5.4 ± 0.7

Values are mean ± SD. COPD: Chronic obstructive pulmonary disease; GOLD: Global Initiative for Chronic Obstructive Lung Disease; FEV₁: Forced expiratory volume in the first second; RV: Residual volume: DLCO: Diffusion capacity for carbon monoxide of the lungs; PaO₂: Arterial oxygen tension; PaCO₂: Arterial carbon dioxide tension; 3DE: Three-dimensional echocardiography; RV/ LVEF; Right and Left ventricle ejection fraction.^§ Former, current and never smoker, respectively.

Table 2. Hemodynamic and echocardiographic characteristics in COPD

Variables (unit)	COPD (n = 100)
RHC data
sPAP (mmHg)	31 ± 8
dPAP (mmHg)	11 ± 6
mPAP (mmHg)	21 ± 6
mPWP (mmHg)	9 ± 4
mRAP (mmHg)	6 ± 3
TPG (mmHg)	12 ± 5
CI (l/min/m^2)	2.9 ± 0.5
SVI (ml/m^2)	39 ± 7
PVR (WU)	2.3 ± 1.2
Heart rate at RHC (beats/min)	77 ± 13
Systemic systolic blood pressure (mmHg)	139 ± 21
Proportion of mPAP ≥ 25 mmHg (%)	26
Proportion of PWP > 15 mmHg (%)	0
Proportion of PVR > 2 and > 3 WU (%)	35/19
Echocardiographic data
TAPSE (cm)	2.3 ± 0.4
Systemic systolic blood pressure (mmHg)	138 ± 18
Heart rate at echo (beats/min)	75 ± 14
Proportion of pulmonary regurgitation (%)	4
Left ventricular E/Ea	9 ± 2
Left atrial volume (ml/m^2)	23 ± 5
Left ventricular mass index (g/m^2)	77 ± 21

Values are mean ± SD. Abbreviations: PAP = pulmonary artery pressure; s, d, and m: systolic, diastolic and mean; PWP: Pulmonary wedge pressure; RAP: Right atrial pressure; TPG: Transpulmonary pressure gradient; CI:cardiac index; SVI: indexed stroke volume; PVR: Pulmonary vascular resistance; RHC: Right heart catheterization; TAPSE: Tricuspid annular plane systolic excursion.

Figure 2. The panels A, C, E and G, show the relationship between heart rate adjusted pulmonary artery acceleration time (HR-adjusted PAAcT), the tissue Doppler derived right ventricle (RV) systolic myocardial velocity time integral (RVSmVTI), RV dimension to time to peak (RVD/Tpeak) and mPAP derived from Doppler echocardiography by the standard equation: [(0.61 × systolic artery pressure (sPAP)) + 2 mmHg] versus invasive mean pulmonary artery pressure (mPAP), respectively. The horizontal dashed lines represent definition of pulmonary hypertension (mPAP ≥ 25 mm Hg) by invasive right heart catheterization, while the vertical dashed lines reflect elevated mPAP by the PH cutoff value of the echo indices. The number within each quadrant of true-positive, false-negative, false-positive, and true-negative results are shown in the right plots. The red and green dots show misclassified and correctly classified patients, respectively. In panel B, D, F and H corresponding Bland-Altman plots are shown for observed minus estimated mPAP, based on regression equations from the derivation group, versus the average of predicted minus observed values of mPAP. The horizontal lines correspond to the mean difference and 95% limits of agreement. Less accuracy of Doppler echocardiography in estimating mPAP is apparent at high mPAP.

Figure 3. Scatterplots showing the relation between invasive pulmonary vascular resistance (PVR) versus heart rate adjusted pulmonary artery acceleration time (HR-adjusted PAAct) (panel A), right ventricular systolic velocity time integral (RVSmVTI) (panel C) and the recommended method by the Tricuspid regurgitation peak velocity/[(RV outflow tract pulsed Doppler VTI × 10)+0.16] (panel E). Correctly and misclassified subjects are illustrated by green and red dots, respectively. Bland-Altman plots of predicted minus observed PVR (vertical axis) against mean of observed and predicted PVR (horizontal axis) for PAAcT (panel B), RVSmVTI (panel D) and the recommended echo method (panel F). Good agreement with negligible mean difference and narrow limits of agreement for all three indices were observed; however, a tendency for greater negative differences with greater PVR, seen in both panel B, D and F.

Figure 4. Comparative receiver operating characteristic curve analyses are presented in 50 patients (derivation group) for; heart rate adjusted pulmonary artery (HR-adjusted PAAcT), right ventricular (RV) systolic velocity time integral (HR-adjusted RVSmVTI), RV diameter (RVD)/time to peak Sm (RVD/Tpeak), estimation of mPAP from established formula (0.61·systolic PAP+2 mmHg, whereby ^*sPAP is obtained by continuous wave Doppler by tricuspid regurgitation (TR) peak velocity by Bernoulli + right atrial pressure), and echo pulmonary vascular resistance Tricuspid regurgitation peak velocity/[(RV outflow tract pulsed Doppler VTI × 10)+0.16]. The best discriminators for pulmonary hypertension (≥ 25 mmHg) and elevated pulmonary vascular resistance (>2WU) are shown in panel A and B, respectively. Area under the curve superscript (1–8): significant difference (p < 0.05) vs. numbered area under the curve.

Table 3. Diagnostic performance of echocardiographic indices in predicting pulmonary hypertension and elevated PVR in the validation group (n = 50) with cutoff values from the derivation cohort (n = 50)

Echocardiographic test variables	Cutoff	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	DOR
Predicting PH (mPAP ≥ 25 mmHg)
HR-adjusted PAAcT (ms)	<103	85	92	79	94	62
HR-adjusted RVSmVTI (cm)	<2.53	92	86	71	97	77
RVD/Tpeak (cm/s)	>22.5	77	84	63	91	17
TR peak by Bernoulli (mmHg)^*	>39	67	65	62	99	11
0.61× sPAP + 2 (mmHg)^*	≥25	83	88	71	94	36
Predicting PVR (PVR>2WU)
HR-adjusted PAAcT (ms)	<116	64	86	86	66	11
HR-adjusted RVSmVTI (cm)	<2.7	75	82	84	72	14
PVR Abbas (WU)^*	>2.1	68	60	68	60	3

Abbreviations; PPV: positive predictive value; NPV: negative predictive value; DOR: diagnostic odd ratio; HR: heart rate; PAAcT: pulmonary artery acceleration time; RVSmVTI: right ventricle systolic myocardial velocity time integral; RVD/Tpeak: right ventricular dimension to time to peak; TR: tricuspid regurgitation; PVR: pulmonary vascular resistance. ^* Patients (n = 42).

Galiè N, Hoeper MM, Humbert M, Torbicki A, Vachiery JL, Barbera JA, et al. Guidelines for the diagnosis and treatment of pulmonary hypertension. Eur Heart J 2009; 30:2493–2537.

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Bossone E, D’Andrea A, D’Alto M, Citro R, Argiento P, ­Ferrara F, et al. Echocardiography in pulmonary arterial hypertension: from diagnosis to prognosis. J Am Soc Echocardiogr 2013; 26:1–14.

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