Abstract
BackgroundPulmonary arterial (PA) stiffness has an essential contribution to the right ventricular (RV) failure pathogenesis. A comprehensive and multiparameter risk assessment allows predicting mortality and guiding treatment decisions in PA hypertension (PAH). We characterize PA remodeling with intravascular ultrasound (IVUS) in prevalent and stable patients with PAH according to the ESC/ERS risk table and analyze the RV-PA coupling consequences.MethodsTen control subjects and 20 prevalent PAH adult patients underwent right heart catheterization (RHC) with simultaneous IVUS study. We estimated cardiac index (CI), pulmonary vascular resistance, and compliance (PVR, PAC) by standard formulas. From IVUS and RHC data, PA diameter, wall thickness/luminal diameter ratio, and indexes of stiffness (pulsatility, compliance, distensibility, incremental elastic modulus - Einc-, and the stiffness index β) were measured. We evaluated RV-PA coupling by the ratio of tricuspid annular plane systolic excursion to systolic pulmonary arterial pressure (TAPSE/sPAP). The individual average risk was calculated by assigning a score of 1 (low-risk -LR-), 2 (intermediate-risk -IR-), and 3 (high-risk -HR-) for each of seven variables (functional class, six-minute walking test, brain natriuretic peptide, right atrial area and pressure, CI, and PA oxygen saturation) and rounding the average value to the nearest integer.ResultsAll PA segments interrogated showed increased vessel diameter, wall cross-sectional area (WCSA), and stiffness in patients with PAH compared to control subjects. 45% corresponded to LR, and 55% corresponded to IR PAH patients. The different measurements of PA stiffness showed significant correlations with TAPSE/sPAP (r = 0.6 to 0.76) in PAH patients. The IR group had higher PA stiffness and lower relative WCSA than LR patients (P < 0.05), and it is associated with a lower PAC and TAPSE/sPAP (P < 0.05).ConclusionIn prevalent PAH patients, the severity of proximal PA remodeling is related to the risk stratification and associated with PAC and RV-PA coupling impairment beyond the indirect effect of the mean PA pressure. The concomitant assessment of IVUS and hemodynamic parameters at diagnosis and follow-up of PAH patients could be a feasible and safe tool for risk stratification and treatment response of the PA vasculopathy during serial hemodynamic measurements.
Highlights
Emerging evidence supports the idea that vascular stiffening in the pulmonary arterial bed can precede the development of pulmonary hypertension (PH) as an early disease marker and promotes pulmonary vascular remodeling that leads to right ventricular (RV) failure (Sanz et al, 2009; Wang and Chesler, 2011; Lammers et al, 2012)
Women predominate in the pulmonary arteries (PAs) hypertension (PAH) group compared to control subjects (95 versus 60%, P < 0.05). 45% of patients corresponded to low risk and 55% to intermediate risk
Despite a small sample size, our results show that proximal PA remodeling is worse in intermediate-risk than in low-risk PAH patients, leading to RV-PA uncoupling, beyond the indirect effect of the mean pulmonary artery pressure (mPAP)
Summary
Emerging evidence supports the idea that vascular stiffening in the pulmonary arterial bed can precede the development of pulmonary hypertension (PH) as an early disease marker and promotes pulmonary vascular remodeling that leads to right ventricular (RV) failure (Sanz et al, 2009; Wang and Chesler, 2011; Lammers et al, 2012). It has been proposed that the crosstalk between the proximal-elastic and distal-muscular pulmonary arteries (PAs) play a role in the PH progression. Muscularization of distal PAs promotes increased mean arterial pressures, resulting in extensive vessel wall remodeling, stiffening the large PAs in a positive feedback cycle of pathologic vascular remodeling. Arterial stiffness can be obtained by assessing the relation between changes in arterial pressure (“stress”) and changes in arterial volume, cross-sectional area, or diameter (“strain”). Both cardiac magnetic resonance and intravascular ultrasound (IVUS) are increasingly used to evaluate PA dimensions and different arterial. We characterize PA remodeling with intravascular ultrasound (IVUS) in prevalent and stable patients with PAH according to the ESC/ERS risk table and analyze the RV-PA coupling consequences
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