Ventriculo-arterial coupling detects occult RV dysfunction in chronic thromboembolic pulmonary vascular disease.

Chronic thromboembolic disease (CTED) is suboptimally defined by a mean pulmonary artery pressure (mPAP) <25 mmHg at rest in patients that remain symptomatic from chronic pulmonary artery thrombi. To improve identification of right ventricular (RV) pathology in patients with thromboembolic obstruction, we hypothesized that the RV ventriculo-arterial (Ees/Ea) coupling ratio at maximal stroke work (Ees/Eamax sw) derived from an animal model of pulmonary obstruction may be used to identify occult RV dysfunction (low Ees/Ea) or residual RV energetic reserve (high Ees/Ea). Eighteen open chested pigs had conductance catheter RV pressure-volume (PV)-loops recorded during PA snare to determine Ees/Eamax sw This was then applied to 10 patients with chronic thromboembolic pulmonary hypertension (CTEPH) and ten patients with CTED, also assessed by RV conductance catheter and cardiopulmonary exercise testing. All patients were then restratified by Ees/Ea. The animal model determined an Ees/Eamax sw = 0.68 ± 0.23 threshold, either side of which cardiac output and RV stroke work fell. Two patients with CTED were identified with an Ees/Ea well below 0.68 suggesting occult RV dysfunction whilst three patients with CTEPH demonstrated Ees/Ea ≥ 0.68 suggesting residual RV energetic reserve. Ees/Ea > 0.68 and Ees/Ea < 0.68 subgroups demonstrated constant RV stroke work but lower stroke volume (87.7 ± 22.1 vs. 60.1 ± 16.3 mL respectively, P = 0.006) and higher end-systolic pressure (36.7 ± 11.6 vs. 68.1 ± 16.7 mmHg respectively, P < 0.001). Lower Ees/Ea in CTED also correlated with reduced exercise ventilatory efficiency. Low Ees/Ea aligns with features of RV maladaptation in CTED both at rest and on exercise. Characterization of Ees/Ea in CTED may allow for better identification of occult RV dysfunction.

Axell RG ，Messer SJ ，White PA ，McCabe C ，Priest A ，Statopoulou T ，Drozdzynska M ，Viscasillas J ，Hinchy EC ，Hampton-Till J ，Alibhai HI ，Morrell N ，Pepke-Zaba J ，Large SR ，Hoole SP ... -  《Physiological Reports》

Right ventricular dysfunction in chronic thromboembolic obstruction of the pulmonary artery: a pressure-volume study using the conductance catheter.

McCabe C ，White PA ，Hoole SP ，Axell RG ，Priest AN ，Gopalan D ，Taboada D ，MacKenzie Ross R ，Morrell NW ，Shapiro LM ，Pepke-Zaba J ... -  《-》

Impaired Cardiac Reserve and Abnormal Vascular Load Limit Exercise Capacity in Chronic Thromboembolic Disease.

This study was a comprehensive evaluation of cardiopulmonary function in patients with chronic thromboembolic (pulmonary vascular) disease (CTED) during exercise. Exertional dyspnea is frequent following pulmonary embolism, but only a minority of patients eventually develops chronic thromboembolic pulmonary hypertension (CTEPH). Better understanding of the factors that limit exercise capacity in patients with persistent pulmonary artery obstruction could help to further define the entity of CTED. Fifty-two subjects (13 healthy control subjects, 14 CTED patients, and 25 CTEPH patients) underwent cardiopulmonary exercise testing and exercise cardiac magnetic resonance with simultaneous invasive pressure registration. Pulmonary vascular function and right ventricular contractile reserve were assessed through combined invasive pressure measurements and magnetic resonance imaging volume measures. Exercise capacity was reduced by 29% and 57% in patients with CTED and CTEPH respectively, compared with control subjects. Both CTED (3.48 [interquartile range: 2.24 to 4.36] mm Hg × l-1 × min-1) and CTEPH patients (8.85 [interquartile range: 7.18 to 10.4] mm Hg × l-1 × min-1) had abnormal total pulmonary vascular resistance. Right ventricular contractile reserve was reduced in CTED patients compared with control subjects (2.23 ± 0.55 vs. 3.72 ± 0.94), but was still higher than that in CTEPH patients (1.34 ± 0.24; p < 0.001). As opposed to patients with CTEPH in whom right ventricular ejection fraction declined with exercise, right ventricular ejection fraction still increased in patients with CTED, albeit to a lesser extent than in healthy control subjects (interaction p < 0.001), which illustrated the distinct patterns of ventricular-arterial coupling. CTED represents an intermediate clinical phenotype. Exercise imaging unmasks cardiovascular dysfunction not evident at rest and identifies hemodynamically significant disease that results from reduced contractile reserve or increased vascular load.

Claeys M ，Claessen G ，La Gerche A ，Petit T ，Belge C ，Meyns B ，Bogaert J ，Willems R ，Claus P ，Delcroix M ... -  《-》

The effects of exercise on right ventricular contractility and right ventricular-arterial coupling in pulmonary hypertension.

Spruijt OA ，de Man FS ，Groepenhoff H ，Oosterveer F ，Westerhof N ，Vonk-Noordegraaf A ，Bogaard HJ ... -  《-》

Validation of the Tricuspid Annular Plane Systolic Excursion/Systolic Pulmonary Artery Pressure Ratio for the Assessment of Right Ventricular-Arterial Coupling in Severe Pulmonary Hypertension.

Tello K ，Wan J ，Dalmer A ，Vanderpool R ，Ghofrani HA ，Naeije R ，Roller F ，Mohajerani E ，Seeger W ，Herberg U ，Sommer N ，Gall H ，Richter MJ ... -  《-》