Pulmonary Artery Relative Area Change Research Articles

Pulmonary flow assessment by phase-contrast MRI can predict short-term mortality of fibrosing interstitial lung diseases.

Phase-contrast magnetic resonance imaging (PC-MRI) can determine pulmonary hemodynamics non-invasively. Pulmonary hypertension causes changes in pulmonary hemodynamics and is a factor for acute exacerbation and death in interstitial lung diseases (ILD). To determine associations between pulmonary hemodynamics measured by PC-MRI and short-term mortality in patients with ILD. Pulmonary hemodynamics, measured by PC-MRI in 43 patients with ILD, were reviewed retrospectively. Evaluation parameters included heart rate, right cardiac output, average flow, average velocity, acceleration time, acceleration volume (AV), maximal change in flow rate during ejection (M), M/AV, maximum area, minimum area, and relative area change in the pulmonary artery (PA). All causes of death within one year from the day of the MRI examination were assessed by reviewing medical records. Associations between evaluation parameters and outcome were determined by univariate and multivariate Cox regression analysis. Six patients (13.9%) died by the one-year follow-up. Age (hazard ratio [HR] 1.116, 95% confidence interval [CI] 1.015-1.269), average flow (HR 0.932, 95% CI 0.870-0.984), average velocity (HR 0.778, 95% CI 0.573-0.976), right cardiac output (HR 0.870, 95% CI 0.758-0.967), AV (HR 0.840, 95% CI 0.669-0.985), M/AV (HR 1.008, 95% CI 1.001-1.014), and PA relative area change (HR 0.715, 95% CI 0.459-0.928) predicted death in univariate Cox analysis. Multivariate Cox analysis showed decreased right cardiac output (HR 0.547, 95% CI 0.160-0.912) and decreased PA relative area change (HR 0.538, 95% CI 0.177-0.922) were independently associated with death. Reduction in right cardiac output and decreased PA relative area change, detected by PC-MRI, were associated with increased mortality in ILD.

Non-invasive methods for estimating mPAP in COPD using cardiovascular magnetic resonance imaging

PurposePulmonary hypertension (PH) is associated with a poor outcome in chronic obstructive pulmonary disease (COPD) and is diagnosed invasively. We aimed to assess the diagnostic accuracy and prognostic value of non-invasive cardiovascular magnetic resonance (CMR) models.MethodsPatients with COPD and suspected PH, who underwent CMR and right heart catheter (RHC) were identified. Three candidate models were assessed: 1, CMR-RV model, based on right ventricular (RV) mass and interventricular septal angle; 2, CMR PA/RV includes RV mass, septal angle and pulmonary artery (PA) measurements; 3, the Alpha index, based on RV ejection fraction and PA size.ResultsOf 102 COPD patients, 87 had PH. The CMR-PA/RV model had the strongest diagnostic accuracy (sensitivity 92%, specificity 80%, positive predictive value 96% and negative predictive value 63%, AUC 0.93, p<0.0001). Splitting RHC-mPAP, CMR-RV and CMR-PA/RV models by 35mmHg gave a significant difference in survival, with log-rank chi-squared 5.03, 5.47 and 7.10. RV mass and PA relative area change were the independent predictors of mortality at multivariate Cox regression (p=0.002 and 0.030).ConclusionCMR provides diagnostic and prognostic information in PH-COPD. The CMR-PA/RV model is useful for diagnosis, the RV mass index and PA relative area change are useful to assess prognosis.Key Points• Pulmonary hypertension is a marker of poor outcome in COPD.• MRI can predict invasively measured mean pulmonary artery pressure.• Cardiac MRI allows for estimation of survival in COPD.• Cardiac MRI may be useful for follow up or future trials.• MRI is potentially useful to assess pulmonary hypertension in patients with COPD.

Dobutamine stress MRI in pulmonary hypertension: relationships between stress pulmonary artery relative area change, RV performance, and 10-year survival.

In pulmonary hypertension (PH), right ventricular (RV) performance determines survival. Pulmonary artery (PA) stiffening is an important biomechanical event in PH and also predicts survival based on the PA relative area change (RAC) measured at rest using magnetic resonance imaging (MRI). In this exploratory study, we sought to generate novel hypotheses regarding the influence of stress RAC on PH prognosis and the interaction between PA stiffening, RV performance and survival. Fifteen PH patients underwent dobutamine stress-MRI (ds-MRI) and right heart catheterization. RACREST, RACSTRESS, and ΔRAC (RAC STRESS – RAC REST) were correlated against resting invasive hemodynamics and ds-MRI data regarding RV performance and RV-PA coupling efficiency (n’vv [RV stroke volume/RV end-systolic volume]). The impact of RAC, RV data, and n’vv on ten-year survival were determined using Kaplan–Meier analysis. PH patients with a low ΔRAC (<−2.6%) had a worse long-term survival (log-rank P = 0.045, HR for death = 4.46 [95% CI = 1.08–24.5]) than those with ΔRAC ≥ −2.6%. Given the small sample, these data should be interpreted with caution; however, low ΔRAC was associated with an increase in stress diastolic PA area indicating proximal PA stiffening. Associations of borderline significance were observed between low RACSTRESS and low n’vvSTRESS, Δη’VV, and ΔRVEF. Further studies are required to validate the potential prognostic impact of ΔRAC and the biomechanics potentially connecting low ΔRAC to shorter survival. Such studies may facilitate development of novel PH therapies targeted to the proximal PA.

Usefulness of Cardiovascular Magnetic Resonance Indices to Rule In or Rule Out Precapillary Pulmonary Hypertension

BackgroundVarious cardiovascular magnetic resonance (CMR) imaging indices are used to assess pulmonary hypertension (PH; mean pulmonary artery pressure ≥ 25 mm Hg). We compared the value of CMR indices to diagnose precapillary PH in treatment-naive patients evaluated for the first time for known or suspected pulmonary vascular disease. MethodsRight heart catheterization and CMR were performed within 48 hours of each other in 85 consecutive subjects. The tricuspid annular plane systolic excursion, right ventricular (RV) fractional area change (RVFAC), RV ejection fraction, systolic eccentricity index, and RV end-diastolic area over left ventricular end-diastolic area ratio were calculated. The pulmonary artery trunk diameter, main pulmonary artery relative area change, and mean flow velocity were also calculated. ResultsThere were 20 non-PH subjects (14 women/6 men, 55 ± 14 years of age, mean pulmonary artery pressure [mPAP] = 20 ± 4 mm Hg) and 65 precapillary PH subjects (32 women/33 men, 60 ± 15 years of age; P = not significant; mPAP = 46 ± 12 mm Hg; 54% with chronic thromboembolic PH). All CMR indices showed essentially the same (good) value to rule in precapillary PH. The RV end-diastolic area over left ventricular end-diastolic area ratio and RVFAC, which are relatively easy to measure, had a large area under the receiver operating characteristic curve (0.93, with optimal cut-off > 0.96, and 0.92, with optimal cut-off ≤ 35%, respectively), not significantly different from RV ejection fraction. In addition, RVFAC > 45% was documented in none of 65 PH and in 10 of 20 non-PH; thus, in a population similar to ours, RVFAC measurement could potentially have avoided unnecessary catheterization in 50% of non-PH subjects. ConclusionsIn treatment-naive subjects in whom pulmonary vascular disease is highly suspected, right-sided CMR indices distinguish between PH and non-PH patients. RVFAC might have particular value in excluding precapillary PH.

Pulmonary artery relative area change is inversely related to ex vivo measured arterial elastic modulus in the canine model of acute pulmonary embolization

A low relative area change (RAC) of the proximal pulmonary artery (PA) over the cardiac cycle is a good predictor of mortality from right ventricular failure in patients with pulmonary hypertension (PH). The relationship between RAC and local mechanical properties of arteries, which are known to stiffen in acute and chronic PH, is not clear, however. In this study, we estimated elastic moduli of three PAs (MPA, LPA and RPA: main, left and right PAs) at the physiological state using mechanical testing data and correlated these estimated elastic moduli to RAC measured in vivo with both phase-contrast magnetic resonance imaging (PC-MRI) and M-mode echocardiography (on RPA only). We did so using data from a canine model of acute PH due to embolization to assess the sensitivity of RAC to changes in elastic modulus in the absence of chronic PH-induced arterial remodeling. We found that elastic modulus increased with embolization-induced PH, presumably a consequence of increased collagen engagement, which corresponds well to decreased RAC. Furthermore, RAC was inversely related to elastic modulus. Finally, we found MRI and echocardiography yielded comparable estimates of RAC. We conclude that RAC of proximal PAs can be obtained from either MRI or echocardiography and a change in RAC indicates a change in elastic modulus of proximal PAs detectable even in the absence of chronic PH-induced arterial remodeling. The correlation between RAC and elastic modulus of proximal PAs may be useful for prognoses and to monitor the effects of therapeutic interventions in patients with PH.

Pulmonary Artery Relative Area Change Detects Mild Elevations in Pulmonary Vascular Resistance and Predicts Adverse Outcome in Pulmonary Hypertension

The aim of this study was to evaluate the clinical use of magnetic resonance imaging measurements related to pulmonary artery stiffness in the evaluation of pulmonary hypertension (PH). A total of 134 patients with suspected PH underwent right heart catheterization (RHC) and magnetic resonance imaging on a 1.5-T scanner within 2 days. Phase contrast imaging at the pulmonary artery trunk and cine cardiac views were acquired. Pulmonary artery area change (AC), relative AC (RAC), compliance (AC/pulse pressure from RHC), distensibility (RAC/pulse pressure from RHC), right ventricular functional indices, and right ventricular mass were all derived. Regression curve fitting identified the statistical model of best fit between RHC measurements and pulmonary artery stiffness indices. The diagnostic accuracy and prognostic value of noninvasive AC and RAC were also assessed. The relationship between pulmonary vascular resistance and pulmonary artery RAC was best reflected by an inverse linear model. Patients with mild elevation in pulmonary vascular resistance (<4 Woods units) demonstrated reduced RAC (P = 0.02) and increased right ventricular mass index (P < 0.0001) without significant loss of right ventricular function (P = 0.17). At follow-up of 0 to 40 months, 18 patients with PH had died (16%). Analysis of Kaplan-Meier plots showed that both AC and RAC predicted mortality (log-rank test, P = 0.046 and P = 0.012, respectively). Area change and RAC were also predictors of mortality using univariate Cox proportional hazards regression analysis (P = 0.046 and P = 0.03, respectively). Noninvasive assessment of pulmonary artery RAC is a marker sensitive to early increased vascular resistance in PH and is a predictor of adverse outcome.