Tan RS, Kassab G. Right ventricular regional wall curvedness and area strain in patients with repaired tetralogy of Fallot. Am J Physiol Heart Circ Physiol 302: H1306 -H1316, 2012. First published December 30, 2011 doi:10.1152/ajpheart.00679.2011.-A quantitative understanding of right ventricular (RV) remodeling in repaired tetralogy of Fallot (rTOF) is crucial for patient management. The objective of this study is to quantify the regional curvatures and area strain based on three-dimensional (3-D) reconstructions of the RV using cardiac magnetic resonance imaging (MRI). Fourteen (14) rTOF patients and nine (9) normal subjects underwent cardiac MRI scan. 3-D RV endocardial surface models were reconstructed from manually delineated contours and correspondence between end-diastole (ED) and end systole (ES) was determined. Regional curvedness (C) and surface area at ED and ES were calculated as well as the area strain. The RV shape and deformation in rTOF patients differed from normal subjects in several respects. Firstly, the curvedness at ED (mean for 13 segments, 0.030 Ϯ 0.0076 vs. 0.029 Ϯ 0.0065 mm Ϫ1 ; P Ͻ 0.05) and ES (mean for 13 segments, 0.040 Ϯ 0.012 vs. 0.034 Ϯ 0.0072 mm Ϫ1 ; P Ͻ 0.001) was decreased by chronic pulmonary regurgitation. Secondly, the surface area increased significantly at ED (mean for 13 segments, 982 Ϯ 192 vs. 1,397 Ϯ 387 mm 2 ; P Ͻ 0.001) and ES (mean for 13 segments, 576 Ϯ 130 vs. 1,012 Ϯ 302 mm 2 ; P Ͻ 0.001). In particular, rTOF patients had significantly larger surface area than that in normal subjects in the free wall but not for the septal wall. Thirdly, area strain was significantly decreased (mean for 13 segments, 56 Ϯ 6 vs. 34 Ϯ 7%; P Ͻ 0.0001) in rTOF patients. Fourthly, there were increases in surface area at ED (5,726 Ϯ 969 vs. 6,605 Ϯ 1,122 mm 2 ; P Ͻ 0.05) and ES (4,280 Ϯ 758 vs. 5,569 Ϯ 1,112 mm 2 ; P Ͻ 0.01) and decrease in area strain (29 Ϯ 8 vs. 18 Ϯ 8%; P Ͻ 0.001) for RV outflow tract. These findings suggest significant geometric and strain differences between rTOF and normal subjects that may help guide therapeutic treatment. magnetic resonance imaging; curvature; right ventricular remodeling; deformation; three-dimensional reconstruction TETRALOGY OF FALLOT (TOF) is the most common cyanotic congenital heart disease (19). The main features include ventricular septum defect, subpulmonary stenosis, and overriding aorta and right ventricular (RV) hypertrophy. Surgical repair is usually performed in early infancy to widen the passage from the RV to the pulmonary artery and close the ventricular septal defect. This ensures separation of oxygen-rich and oxygenpoor blood flows to the proper chambers. Surgical repair of TOF often involves disruption of pulmonary valve integrity that leads to pulmonary regurgitation (PR; Refs. 8, 37). This in turn causes RV dilation (9, 23) and RV outflow tract (RVOT) aneurysm (2-3, 13, 28 -29). The RV dilation is usually tolerated with little or no symptoms during the first two to three decades of age. If left untreated, however, continued...

Myocardial deformation is a sensitive marker of sub-clinical myocardial dysfunction that carries independent prognostic significance across a broad range of cardiovascular diseases. It is now possible to perform 3D feature tracking of SSFP cines on cardiac magnetic resonance imaging (FT-CMR). This study provides reference ranges for 3D FT-CMR and assesses its reproducibility compared to 2D FT-CMR. One hundred healthy individuals with 10 men and women in each of 5 age deciles from 20 to 70 years, underwent 2D and 3D FT-CMR of left ventricular myocardial strain and strain rate using SSFP cines. Good health was defined by the absence of hypertension, diabetes, obesity, dyslipidaemia, or any cardiovascular, renal, hepatic, haematological and systemic inflammatory disease. Normal values for myocardial strain assessed by 3D FT-CMR were consistently lower compared with 2D FT-CMR measures [global circumferential strain (GCS) 3D − 17.6 ± 2.6% vs. 2D − 20.9 ± 3.7%, P < 0.005]. Validity of 3D FT-CMR was confirmed against other markers of systolic function. The 3D algorithm improved reproducibility compared to 2D, with GCS having the best inter-observer agreement [intra-class correlation (ICC) 0.88], followed by global radial strain (GRS; ICC 0.79) and global longitudinal strain (GLS, ICC 0.74). On linear regression analyses, increasing age was weakly associated with increased GCS (R 2 = 0.15, R = 0.38), peak systolic strain rate, peak late diastolic strain rate, and lower peak early systolic strain rate. 3D FT-CMR offers superior reproducibility compared to 2D FT-CMR, with circumferential strain and strain rates offering excellent intra-and inter-observer variability. Normal range values for myocardial strain measurements using 3D FT-CMR are provided.

Vascular wall stiffness and hemodynamic parameters are potential biomechanical markers for detecting pulmonary arterial hypertension (PAH). Previous computational analyses, however, have not considered the interaction between blood flow and wall deformation. Here, we applied an established computational framework that utilizes patient-specific measurements of hemodynamics and wall deformation to analyze the coupled fluid–vessel wall interaction in the proximal pulmonary arteries (PA) of six PAH patients and five control subjects. Specifically, we quantified the linearized stiffness (E), relative area change (RAC), diastolic diameter (D), regurgitant flow, and time-averaged wall shear stress (TAWSS) of the proximal PA, as well as the total arterial resistance (Rt) and compliance (Ct) at the distal pulmonary vasculature. Results found that the average proximal PA was stiffer [median: 297 kPa, interquartile range (IQR): 202 kPa vs. median: 75 kPa, IQR: 5 kPa; P = 0.007] with a larger diameter (median: 32 mm, IQR: 5.25 mm vs. median: 25 mm, IQR: 2 mm; P = 0.015) and a reduced RAC (median: 0.22, IQR: 0.10 vs. median: 0.42, IQR: 0.04; P = 0.004) in PAH compared to our control group. Also, higher total resistance (Rt; median: 6.89 mmHg × min/l, IQR: 2.16 mmHg × min/l vs. median: 3.99 mmHg × min/l, IQR: 1.15 mmHg × min/l; P = 0.002) and lower total compliance (Ct; median: 0.13 ml/mmHg, IQR: 0.15 ml/mmHg vs. median: 0.85 ml/mmHg, IQR: 0.51 ml/mmHg; P = 0.041) were observed in the PAH group. Furthermore, lower TAWSS values were seen at the main PA arteries (MPAs) of PAH patients (median: 0.81 Pa, IQR: 0.47 Pa vs. median: 1.56 Pa, IQR: 0.89 Pa; P = 0.026) compared to controls. Correlation analysis within the PAH group found that E was directly correlated to the PA regurgitant flow (r = 0.84, P = 0.018) and inversely related to TAWSS (r = −0.72, P = 0.051). Results suggest that the estimated elastic modulus E may be closely related to PAH hemodynamic changes in pulmonary arteries.

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BackgroundConcomitant pulmonary hypertension and interstitial lung disease in systemic sclerosis (SSc-PH-ILD) represents a distinct subpopulation of SSc with poorer prognosis in Western studies. In Asian patients, characterisation of SSc-PH-ILD is still lacking.ObjectivesTo analyse hospital admissions, survival and prognostic markers among SSc patients with PH, ILD or concomitant PH-ILD in the Scleroderma Cohort Singapore.MethodsIn this study involving 3 tertiary Rheumatology institutions Jan 2008 to , Oct 2016 SSc patients with significant pulmonary involvement were included. ILD was based on high resolution computed tomography and predicted FVC <70%. PH was based on either echocardiographic systolic pulmonary arterial pressure (sPAP) ≥50 mmHg, or right heart catheterization (RHC) findings of mean PAP≥25 mmHg. Hospitalisation rates and survival of SSc patients with PH, ILD or PH-ILD were compared. Risk factors of poor outcomes were identified by multivariate stepwise Cox regression analysis.ResultsAmong 490 patients, 92 had ILD, 50 PH and 43 PH-ILD (table 1). Of 93 patients with PH or PH-ILD, 56 were based on echocardiography and 37 on RHC. The 5 year survival was 79%, 87% and 90% in PH, PH-ILD and ILD subgroup, respectively (figure 1). In multivariable analysis, PH was significantly associated with 2.8-fold increased risk of death. Male gender, malabsorption, digital ulcerations and renal crisis were also significantly associated with mortality (table 2). No significant difference in hospital admissions/year among different subgroups. Increased hospital admissions were associated with renal crisis, right heart failure and use of PH medications.Abstract FRI0453 – Table 1Clinical characteristicsPH (n=50)ILD (n=92)PH-ILD (n=43)No PH/ILD (n=305) Female, n447638270Follow up duration (months±SD)53.46±55.76101.5±80.0488.71±65.5364.66±36.27Age at SSc diagnosis (years±SD)51.08±16.4446.87±12.453.84±15.1746.44±14.59Duration of SSc at entry (years±SD)5.85±6.956.93±7.456.14±7.985.20±8.24Dc-SSc, n134511100PH specific treatments+, n28N/A26N/AImmunosuppressants++, n256427176+Prostacyclin, phosphodiesterase type 5 inhibitors, endothelin receptor antagonist;++Methotrexate, cyclophosphamide, mycophenolate mofetil.Abstract FRI0453 – Table 2Survival analysisHazard Ratio (95% CI)P Value Male gender2.85 (1.53–5.33)0.0010Malabsorption2.89 (1.67–5.01)0.0002Renal crisis2.00 (1.00–3.99)0.0490Digital ulcerations2.06 (1.21–3.50)0.0076Abstract FRI0453 – Figure 1Adjusted survival curve comparing survival of SSc patients with PH, ILD, and concomittant PH-ILD. X-axis shows years of survival from diagnosis of PH or ILD.ConclusionsCompared to those with ILD or PH-ILD, SSc-PH patients had increased mortality, but not hospitalisation rates. This could be due to small sample size or short follow up duration. We identified risk factors associated with worse outcomes in SSc patients with significant pulmonary involvement.Disclosure of InterestNone declared