Bone Morphogenetic Protein Receptor Type 2 Mutation in Pulmonary Arterial Hypertension: A View on the Right Ventricle.

BACKGROUND: The effect of a mutation in the bone morphogenetic protein receptor 2 (BMPR2) gene on right ventricular (RV) pressure overload in patients with pulmonary arterial hypertension is unknown. Therefore, we investigated RV function in patients who have pulmonary arterial hypertension with and without the BMPR2 mutation by combining in vivo measurements with molecular and histological analysis of human RV and left ventricular tissue. METHODS AND RESULTS: In total, 95 patients with idiopathic or familial pulmonary arterial hypertension were genetically screened for the presence of a BMPR2 mutation: 28 patients had a BMPR2 mutation, and 67 patients did not have a BMPR2 mutation. In vivo measurements were assessed using right heart catheterization and cardiac MRI. Despite a similar mean pulmonary artery pressure (noncarriers 54±15 versus mutation carriers 55±9 mm Hg) and pulmonary vascular resistance (755 [483-1043] versus 931 [624-1311] dynes·s(-1)·cm(-5)), mutation carriers presented with a more severely compromised RV function (RV ejection fraction: 37.6±12.8% versus 29.0±9%: P<0.05; cardiac index 2.7±0.9 versus 2.2±0.4 L·min(-1)·m(-2)). Differences continued to exist after treatment. To investigate the role of transforming growth factor ß and bone morphogenetic protein receptor II signaling, human RV and left ventricular tissue were studied in controls (n=6), mutation carriers (n=5), and noncarriers (n=11). However, transforming growth factor ß and bone morphogenetic protein receptor II signaling, and hypertrophy, apoptosis, fibrosis, capillary density, inflammation, and cardiac metabolism, as well, were similar between mutation carriers and noncarriers. CONCLUSIONS: Despite a similar afterload, RV function is more severely affected in mutation carriers than in noncarriers. However, these differences cannot be explained by a differential transforming growth factor ß, bone morphogenetic protein receptor II signaling, or cardiac adaptation.

Contrast-enhanced perfusion magnetic resonance imaging for head and neck squamous cell carcinoma: a systematic review.

This systematic review gives an extensive overview of the current state of perfusion-weighted magnetic resonance imaging (MRI) for head and neck squamous cell carcinoma (HNSCC). Pubmed and Embase were searched for literature until July 2014 assessing the diagnostic and prognostic performance of perfusion-weighted MRI in HNSCC. Twenty-one diagnostic and 12 prognostic studies were included for qualitative analysis. Four studies used a T2(∗) sequence for dynamic susceptibility (DSC)-MRI, 29 studies used T1-based sequences for dynamic contrast enhanced (DCE)-MRI. Included studies suffered from a great deal of heterogeneity in study methods showing a wide range of diagnostic and prognostic performance. Therefore we could not perform any useful meta-analysis. Perfusion-weighted MRI shows potential in some aspects of diagnosing HNSCC and predicting prognosis. Three studies reported significant correlations between hypoxia and tumor heterogeneity in perfusion parameters (absolute correlation coefficient |ρ|>0.6, P<0.05). Two studies reported synergy between perfusion-weighted MRI and positron emission tomography (PET) parameters. Four studies showed a promising role for response prediction early after the start of chemoradiotherapy. In two studies perfusion-weighted MRI was useful in the detection of residual disease. However more research with uniform study and analysis protocols with larger sample sizes is needed before perfusion-weighted MRI can be used in clinical practice.

The right ventricle explains sex differences in survival in idiopathic pulmonary arterial hypertension.

BACKGROUND: Male sex is an independent predictor of worse survival in pulmonary arterial hypertension (PAH). This finding might be explained by more severe pulmonary vascular disease, worse right ventricular (RV) function, or different response to therapy. The aim of this study was to investigate the underlying cause of sex differences in survival in patients treated for PAH. METHODS: This was a retrospective cohort study of 101 patients with PAH (82 idiopathic, 15 heritable, four anorexigen associated) who were diagnosed at VU University Medical Centre between February 1999 and January 2011 and underwent right-sided heart catheterization and cardiac MRI to assess RV function. Change in pulmonary vascular resistance (PVR) was taken as a measure of treatment response in the pulmonary vasculature, whereas change in RV ejection fraction (RVEF) was used to assess RV response to therapy. RESULTS: PVR and RVEF were comparable between men and women at baseline; however, male patients had a worse transplant-free survival compared with female patients (P = .002). Although male and female patients showed a similar reduction in PVR after 1 year, RVEF improved in female patients, whereas it deteriorated in male patients. In a mediator analysis, after correcting for confounders, 39.0% of the difference in transplant-free survival between men and women was mediated through changes in RVEF after initiating PAH medical therapies. CONCLUSIONS: This study suggests that differences in RVEF response with initiation of medical therapy in idiopathic PAH explain a significant portion of the worse survival seen in men.

Effects of diaphragm plication on pulmonary function and cardiopulmonary exercise parameters.

OBJECTIVES: Paralysis of the diaphragm is an uncommon condition, which may result in dyspnoea on excertion and in orthopnea. In patients who have symptoms, the paralysed diaphragm is often plicated to prevent its paradoxical movement on inspiration. This procedure brings relief to many patients, but the mechanism for this improvement is not well understood. METHODS: Nine symptomatic patients who underwent plication of a unilateral paralysed hemidiaphragm were prospectively evaluated. All patients underwent pulmonary function tests and cardiopulmonary exercise tests before surgery and repeated them after surgery. RESULTS: Patients with hemidiaphragm paralysis before surgery were found to have lower tidal volumes at any given ventilation rate during exercise than normal subjects. A clear and consistent change was found in the manner in which patients increased their ventilation during exercise after surgery. All patients showed an increase in tidal volume for a given ventilation rate, which was significant. The plication procedure reduced the respiratory rate for any exercise level in all patients, and this effect was more pronounced during exercise. CONCLUSIONS: In patients with hemidiaphragm paralysis who underwent a diaphragm plication exercise, tidal volumes increased and the ventilatory frequency decreased. Despite this improvement, maximal exercise capacity remained unaltered.

Accurate assessment of load-independent right ventricular systolic function in patients with pulmonary hypertension.

BACKGROUND: End-systolic elastance (E(es)), a load-independent measure of ventricular function, is of clinical interest for studies of the right ventricle (RV) in patients with pulmonary arterial hypertension (PAH). The objective of this study was to determine whether, in PAH patients, E(es) can be estimated from mean pulmonary artery pressure (mPAP) and end-systolic volume (ESV) only. METHODS: Right heart catheterization was used to measure mPAP. Maximal isovolumic pressure (P(iso)) was estimated from RV pressure curves with the so-called single-beat method. Cardiac magnetic resonance imaging (MRI) was used to assess RV end-diastolic and end-systolic volumes (EDV and ESV). E(es) was then calculated as: E(es) = (P(iso)-mPAP) / (EDV-ESV), and as E(es,V0 = 0) = mPAP/ESV (simplified method, with V0 = 0, is negligible volume at zero pressure). Right ventricular volume at zero pressure (V(0)) was then defined as the intercept of the end-systolic pressure-volume relation (single-beat method) with the horizontal axis. RESULTS: E(es,V0 = 0) was significantly lower compared with E(es) (0.61 vs 1.34 mm Hg/ml, respectively, p<0.01). A modified Bland-Altman analysis showed a contractility-dependent difference between E(es,V0 = 0) and E(es). Moreover, V(0) ranged from-8 up to 171 ml, and a moderate and good correlation was found between V(0) and EDV, and V(0) and ESV, respectively (r = 0.65 and r = 0.87, p< 0.01). CONCLUSIONS: These findings show that V(0) is dependent on RV dilation. Therefore, the assumption that V(0) is negligible in PAH is incorrect. Consequently, for an accurate assessment of load-independent RV systolic function, RV volumes and pressure curves are required.

Monitoring response to antiangiogenic therapy in non-small cell lung cancer using imaging markers derived from PET and dynamic contrast-enhanced MRI.

UNLABELLED: With antiangiogenic agents, tumor shrinkage may be absent, despite survival benefit. The present study assessed the predictive value of molecular imaging for the identification of survival benefit during antiangiogenic treatment with bevacizumab and erlotinib in patients with advanced non-small cell lung cancer. METHODS: Patients were evaluated using an imaging protocol including CT, 18F-FDG PET, H2(15)O PET, and dynamic contrast-enhanced MRI to derive measurements on tumor size, glucose metabolism, perfusion, and microvascular permeability. The percentage change in imaging parameters after 3 wk of treatment as compared with baseline was calculated and correlated with progression-free survival (PFS). RESULTS: Forty-four patients were included, and 40 underwent CT and 18F-FDG PET at both time points. Complete datasets, containing all imaging modalities, were available for 14 patients. Bevacizumab and erlotinib treatment resulted in decreased metabolism, perfusion, and tumor size. A decrease in standardized uptake value or tumor perfusion of more than 20% at week 3 was associated with longer PFS (9.7 vs. 2.8 mo, P=0.01, and 12.5 vs. 2.9 mo, P=0.009, respectively). Whole-tumor Ktrans (the endothelial transfer constant) was not associated with PFS, but patients with an increase of more than 15% in the SD of tumor Ktrans values-that is, an increase in regions with low or high Ktrans values-after 3 wk had shorter PFS (2.3 vs. 7.0 mo, P=0.008). A partial response, according to the response evaluation criteria in solid tumors (RECIST), at week 3 was also associated with prolonged PFS (4.6 vs. 2.9 mo, P=0.017). However, 40% of patients with a partial response as their best RECIST response still had stable disease at week 3. In these cases tumor perfusion was already decreased and Ktrans heterogeneity showed no increase, indicating that the latter parameters seem to be more discriminative than RECIST at the 3-wk time point. CONCLUSION: PET and dynamic contrast-enhanced MRI were able to identify patients who benefit from bevacizumab and erlotinib treatment. Molecular imaging seems to allow earlier response evaluation than CT.

Prognostic value of right ventricular mass, volume, and function in idiopathic pulmonary arterial hypertension.

AIMS: This study investigated the relationship between right ventricular (RV) structure and function and survival in idiopathic pulmonary arterial hypertension (IPAH). METHODS AND RESULTS: In 64 patients, cardiac magnetic resonance, right heart catheterization, and the six-minute walk test (6MWT) were performed at baseline and after 1-year follow-up. RV structure and function were analysed as predictors of mortality. During a mean follow-up of 32 months, 19 patients died. A low stroke volume (SV), RV dilatation, and impaired left ventricular (LV) filling independently predicted mortality. In addition, a further decrease in SV, progressive RV dilatation, and further decrease in LV end-diastolic volume (LVEDV) at 1-year follow-up were the strongest predictors of mortality. According to Kaplan-Meier survival curves, survival was lower in patients with an inframedian SV index or= 84 mL/m(2), and an inframedian LVEDV

Quantification of left ventricular volumes and ejection fraction using freehand transthoracic three-dimensional echocardiography: comparison with magnetic resonance imaging.

OBJECTIVES: Our aim was to validate 3-dimensional echocardiography (3DE) for assessment of left ventricular (LV) end-diastolic volume, end-systolic volume (ESV), stroke volume, and ejection fraction (EF) using the freehand-acquisition method. Furthermore, LV volumes by breath hold-versus free breathing-3DE acquisition were assessed and compared with magnetic resonance imaging (MRI). METHODS: From the apical position, a fan-like 3DE image was acquired during free breathing and another, thereafter, during breath hold. In 27 patients, 28 breath hold- and 24 free breathing-3DE images were acquired. A total of 17 patients underwent both MRI and 3DE. MRI contours were traced along the outer endocardial contour, including trabeculae, and along the inner endocardial contour, excluding trabeculae, from the LV volume. RESULTS: All 28 (100%) breath hold- and 86% of free breathing-3DE acquisitions could be analyzed. Intraobserver variation (percentual bias +/- 2 SD) of end-diastolic volume, ESV, stroke volume, and EF for breath-hold 3DE was, respectively, 0.3 +/- 10.2%, 0.3 +/- 14.6%, 0.1 +/- 18.4%, and -0.1 +/- 5.8%. For free-breathing 3DE, findings were similar. A significantly better interobserver variability, however, was observed for breath-hold 3DE for ESV and EF. Comparison of breath-hold 3DE with MRI inner contour showed for end-diastolic volume, ESV, stroke volume, and EF, a percentual bias (+/- 2 SD) of, respectively, -13.5 +/- 26.9%, -17.7 +/- 47.8%, -10.6 +/- 43.6%, and -1.8 +/- 11.6%. Compared with the MRI outer contour, a significantly greater difference was observed, except for EF. CONCLUSIONS: 3DE using the freehand method is fast and highly reproducible for (serial) LV volume and EF measurement, and, hence, ideally suited for clinical decision making and trials. Breath-hold 3DE is superior to free-breathing 3DE regarding image quality and reproducibility. Compared with MRI, 3DE underestimates LV volumes, but not EF, which is mainly explained by differences in endocardial contour tracing by MRI (outer contour) and 3DE (inner contour) of the trabecularized endocardium. Underestimation is reduced when breath-hold 3DE is compared with inner contour analysis of the MRI dataset.