Pulmonary Vascular Resistance (PVR)

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Eur Respir J 2015

Pulmonary Vascular Resistance (PVR) Pulmonary circulation is a low pressure, low resistance circuit During exercise a healthy subject can increase cardiac output 4-5 times while MPAP increases 2-3 times normal (almost doubles the resting lung capillary blood volume) Capillary recruitment Vascular distention

PVR and the heart

Pulmonary Vascular Resistance (PVR) is a major factor causing exercise limitation PVR increases in diseases that cause obliteration or destruction of the pulmonary vascular bed Symptoms: Dyspnea ( increased VD/VT, wasted ventilation) Fatigue, fainting (ventricular interdependence and systemic cardiovascular effects) Hypoxemia (short transit time in healthy regions, intracardiac (PFO) or intrapulmonary shunt, low SVO2)

Determinants of PVR PVR = pulmonary vascular resistance LAP = left atrial pressure Q = cardiac output R0 = total pulmonary vascular resistance = pulmonary vascular distensibility

Eur Respir J 2009

Mean pulmonary arterial pressure (P pa) during rest and slight supine exercise in healthy subjects aged 18 30 yrs ( ; n = 144), 30 50 yrs ( ; n = 169) and 50 yrs ( ; n = 91 The data of this review do not support the current threshold of Ppa during exercise. According to the reviewed data, nearly half of subjects aged>50 yrs are expected to develop a Ppa>30 mmhg during slight exercise and about 20% of subjects aged<50 yrs are expected to exceed this value during maximal exercise G. Kovacs et al. Eur Respir J 2009

Modeled mean pulmonary arterial pressure-cardiac output (mpap-q) relationships during dynamic exercise with progressively increased distensibility coefficients (). Distensibility decreases with age Gregory D. Lewis et al. Circulation. 2013

Rajeev Malhotra et al. Circ Heart Fail. 2016

The mpap/co relationship reflects the RV afterload in relation to pulmonary blood flow, integrating the RV capacity and the severity of pulmonary vasculopathy Gregory D. Lewis et al. Circulation. 2013

Herve et al, Eur Respir J 2015

Eur Respir J 2017

Pulmonary Medicine 2012

Ventricular interdependence in COPD- hemodynamic consequences Shujaat et al, Pulmonary Medicine 2012

Chest 1992

Heart 2009

Portillo et al. International Journal of COPD 2015

Eur Respr J 2013

CHEST 1996

Eur Respir Rev 2017

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27 ILD pts, 15 with PVD Degani-Costa et al ERJ 2015

Figure 4. Pathophysiology of exercise limitation of PPH patients. Circulation. 2001

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CPET safety in high risk cardiovascular population 5060 CPETs in 4250 pts 8 adverse effects 0 deaths Skalski et al, Circulation 2012

CPET Arena and Sietsema. Circulation, 2011

Ventilatory efficiency = Ventilatory equivalent for CO2 (VE/VCO2) Normal value: VE/ VCO2@AT: 34 Increased = inefficient ventilation, perceived as dyspnea disproportionate for the task Increased when: -increased dead space (pulmonary airways, pulmonary vascular disease, heart failure) -hypoxemia -early lactic acidosis -sympathetic stimulation

Eur Respir J 2004

52 PPH patients vs 9 controls CHEST 2005

Pulmonary vasculopathy detection via CPET Yasunobou et al, CHEST 2005

π π ESC/ERS, Eur Heart J 2015

Cardiopulmonary exercise testing for detecting pulmonary arterial hypertension in systemic sclerosis Dumitrescu et al, Heart 2017

Circulation, 2008

29 patients with systemic sclerosis without significant lung fibrosis and without known pulmonary arterial hypertension

Oliveira et al. Pulmonary Circulation 2017

Transplant- free survival of 72 systemic sclerosis patients according to hemodynamic classification Eur Respir J 2016

After 24 weeks, 6-minute walking distance significantly improved, by a mean SD of 44.5 10.3 meters. ARTHRITIS & RHEUMATISM 2012

Grünig et al. Eur Respir J 2012

Individual changes in the 6-min walk distance (6MWD) in pulmonary hypertension subgroups with different aetiologies from baseline to week 3 and 15. Grünig et al. Eur Respir J 2012

Arthritis Research & Therapy 2012

European Heart Journal 2016

Effects of aerobic training on ventilation during exercise

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25 COPD patients with deteriorating symptoms (10 with PH and 15 without PH after RHC) (peak VO2, VO2/HR, VO2/ WR similar)

Respirology 2011

Pulmonary Medicine 2012

30 SSc patients not clinically suspected of having significant pulmonary vascular disease PLoS one 2010

Respiration 2015

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McLaughlin et al, JACC 2013

20 patients with PPH under inhaled iloprost or oral beraprost alone (baseline) and 3 months after bosentan add-on. Eur Respir J 2003

Effect of sildenafil on ventilatory efficiency and exercise tolerance in Pulmonary Hypertension Oudiz et al, Eur J Heart Fail. 2007

Iwase et al, Heart 2001

Η υ Χ υ Η Η υ1, φ 1, Η: υ2, π π 1, υ Η Η υ 16 π 1, 1, Γ Η Η Ω φ υ1, υ1, Η φ π υ - 1 1 «Γ. π υ π», 2 Δ φ,γ 14,3 0,001 5,8 10,9 0,065 Δ VE/VCO2 at AT -5,1 5,7 0,004 Δ VE/VCO2 peak -3,3 7,7 0,124 4,1 9 0,096-0,9 9,7 0,735 Δ AT Δ PETCO2 at AT Δ PETCO2 peak Συμπέρσμ Σ π φ π υ υπ. π π π. Η CPET π υ VE/ 15,9 p π Δ peak VO2 Θ π, π 30 2003 π π π π φ

24 month survival of PAH- CTEPH patients predicted by ventilatory efficiency Schwaiblmair et al, BMC Pulmonary Medicine 2012

Chest 2016

Conclusions the earliest and often only symptoms of patients with PH manifest during physical activity resting hemodynamics do not correlate well with functional capacity, response to treatment and survival exercise performance has been established as the primary end-point in studies evaluating treatment exercise induced PH may lead to earlier diagnosis and treatment serial exercise testing is an objective and reliable way to evaluate treatment effectiveness over time