The Relationship Between the Components of Pulmonary Artery Pressure Remains Constant Under All Conditions in Both Health and Disease

Syyed, Raheel; Reeves, John Τ.; Welsh, David; Raeside, David; Johnson, Martin K.; Peacock, Andrew J.

doi:10.1378/chest.07-1367

Cited by 102 publications

(97 citation statements)

References 13 publications

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“…The tight correlation between systolic, mean, and diastolic Ppa was recently rediscovered, with similar prediction equations that interestingly remained valid in pulmonary hypertension of various severities and aetiologies [15][16][17]. This is explained by the monotonous response of the pulmonary circulation to insults, leading to proportional inverse changes in Cpa and PVR with an unaltered time constant Cpa 6 PVR 0.6-0.7 s [18,19].…”

Section: Series: Physiology In Respiratory Medicine R Naeije Et Almentioning

confidence: 83%

The transpulmonary pressure gradient for the diagnosis of pulmonary vascular disease

Naeije¹,

et al. 2012

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The transpulmonary pressure gradient (TPG), defined by the difference between mean pulmonary arterial pressure (Ppa) and left atrial pressure (Pla; commonly estimated by pulmonary capillary wedge pressure: Ppcw) has been recommended for the detection of intrinsic pulmonary vascular disease in left-heart conditions associated with increased pulmonary venous pressure. In these patients, a TPG of .12 mmHg would result in a diagnosis of ''out of proportion'' pulmonary hypertension. This value is arbitrary, because the gradient is sensitive to changes in cardiac output and both recruitment and distension of the pulmonary vessels, which decrease the upstream transmission of Pla. Furthermore, pulmonary blood flow is pulsatile, with systolic Ppa and mean Ppa determined by stroke volume and arterial compliance. It may, therefore, be preferable to rely on a gradient between diastolic Ppa and Ppcw. The measurement of a diastolic Ppa/Ppcw gradient (DPG) combined with systemic blood pressure and cardiac output allows for a step-by-step differential diagnosis between pulmonary vascular disease, high output or high leftheart filling pressure state, and sepsis. The DPG is superior to the TPG for the diagnosis of ''out of proportion'' pulmonary hypertension.

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Section: Series: Physiology In Respiratory Medicine R Naeije Et Almentioning

confidence: 83%

The transpulmonary pressure gradient for the diagnosis of pulmonary vascular disease

Naeije¹,

et al. 2012

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“…These proportional relationships indeed remain over a wide range of pulmonary artery pressures in healthy individuals and PAH ( fig. 5) [48,49]. Thus, we propose that these proportional relationships are the reflection of the hyperbolic relationship between PVR and arterial compliance.…”

Section: Consequences Of the Constant Product Of Resistance And Complmentioning

confidence: 83%

The arterial load in pulmonary hypertension

Saouti¹,

Westerhof²,

Postmus³

et al. 2010

Eur Respir Rev

186

153

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The anatomical differences between the pulmonary and systemic arterial system are the main cause of the difference in distribution of compliance. In the pulmonary arterial system compliance is distributed over the entire arterial system, and stands at the basis of the constancy of the RC-time. This distribution depends on the number of peripheral vessels, which is ,8-10 times more in the pulmonary system than the systemic tree. In the systemic arterial tree the compliance is mainly located in the aorta (80% of total compliance in thoracic-abdominal aorta).The constant RC-time in the pulmonary bed results in proportionality of systolic and diastolic pressure with mean pressure and, in turn, in the constant ratio of oscillatory and mean power.KEYWORDS: Compliance, pulmonary hypertension, resistance, systemic circulation, Windkessel T he common feature of pulmonary and the systemic circulation is that both transport an equal amount of blood. However, a major difference is that the pulmonary circulation works at much lower pressures than the systemic circulation. Pulmonary pressure is lower as resistance is lower and the pulmonary vasculature is more compliant. In pulmonary hypertension, the right ventricular load increases due to an increase in pulmonary vascular resistance and decrease in pulmonary vascular compliance, ultimately leading to right ventricular failure. In recent years it has become clear that in pulmonary hypertension not only the contribution of resistance is of importance but that the decrease in arterial compliance plays an equally important role. In addition, in pulmonary hypertension the changes in resistance and compliance are fundamentally and quantitatively different from those in systemic hypertension. Therefore, changes in the pulmonary arterial tree and in pressure are considerably larger than in the systemic arterial tree.This review describes the most important components of the arterial load on the right ventricle (RV) in terms of resistance and arterial compliance, and the consequences of load changes for right ventricular work and function. We will conclude with a short comparison of the pulmonary and systemic circulation in health and hypertension. While the hydraulic load describes the load that the ventricular pump experiences, the muscles generate and feel wall stress, which is considered the muscular afterload. In general higher impedance relates to higher wall stress.

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“…9 Although few studies questioned the reliability of this Doppler-based method of estimating SPAP, 17,[19][20][21][22] two recent retrospective studies involving 1,695 and 310 patients proved the significance of this formula in determining the SPAP accurately. 28,29 In the study by Syyed et al, 30 they derived a formula for measuring MPAP from SPAP as MPAP = 0.65 (SPAP) + 0.55 mm Hg. In another study by Chemla et al, 31 they derived the formula for MPAP from SPAP as MPAP = 0.6 (SPAP) + 2, which was subsequently studied by D'Alto et al 21 and found to be correlating better with the MPAP measured invasively.…”

Section: Discussionmentioning

confidence: 99%

Derivation and Validation of Formula relating Pulmonary Acceleration Time and Mean Pulmonary Artery Pressure in Indian Population

Ganesan¹

2017

Journal of Perioperative Echocardiography

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Background: Pulmonary acceleration time (PAT) forms a valuable echocardiographic parameter in deriving the mean pulmonary artery pressure (MPAP). The present study aims to derive and validate a formula relating MPAP and PAT in an Indian population. Materials and methods:Preoperative echocardiography was performed in 22 adult cardiac surgery patients undergoing coronary artery bypass grafting (CABG) and/or mitral valve replacement. The PAT, PAT/right ventricular ejection time (RVET), PAT corrected for heart rate [(HR) HRcPAT], and tricuspid regurgitation (TR) peak velocity were correlated with MPAP measured from pulmonary artery (PA) catheter, and a new formula relating MPAP and PAT was derived and subsequently validated in another cohort of 21 patients. Results:The PAT, HRcPAT, and PAT/RVET correlated well (r 2 = 0.69, 0.68 and 0.47 respectively, p < 0.0001), while TR velocity correlated poorly with MPAP (r 2 = 0.20, p = 0.046). The cutoff values of PAT and HRcPAT for diagnosing pulmonary artery hypertension (PAH) (MPAP = 25 mm Hg) were 74 and 99 respectively, with 92% sensitivity and 100% specificity. The derived formula (MPAP = 62.4 − 0.3 PAT) correlated well with the standard formula (79−0.45 PAT) on applying in the validation cohort (Bland-Altman plot, bias <10%). In subgroup analysis, patients with severe PAH (MPAP = 50 mm Hg) showed better correlation than patients with less than severe PAH (r 2 =0.633, p=0.038 and r 2 = 0.46, p = 0.108 respectively). Similarly, the formula for deriving pulmonary vascular resistance index (PVRI) from PAT [(PVRI = 14.9−0.09 pulmonary artery acceleration time (PAAT)] correlated well with the existing formula (PVRI = 9 − 0.07 PAAT). The inter-and intraobserver variabilities were not significant. Conclusion:The indexed formula is better in predicting MPAP from PAT in Indian population, particularly in patients with severe PAH (MPAP = 50 mm Hg) and the cutoffs of PAT and HRcPAT in predicting PAH (MPAP = 25 mm Hg) in an Indian population are 74 and 99 msec respectively.

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The Relationship Between the Components of Pulmonary Artery Pressure Remains Constant Under All Conditions in Both Health and Disease

Cited by 102 publications

References 13 publications

The transpulmonary pressure gradient for the diagnosis of pulmonary vascular disease

The transpulmonary pressure gradient for the diagnosis of pulmonary vascular disease

The arterial load in pulmonary hypertension

Derivation and Validation of Formula relating Pulmonary Acceleration Time and Mean Pulmonary Artery Pressure in Indian Population

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