Increased peak wall stress correlates with change in VSMC towards a synthetic phenotype mediated by ROS accumulation via CTGF. Understanding the molecular mechanisms that regulate VSMC towards a synthetic phenotype could unveil new regulatory pathways of aortic homoeostasis and impact the risk-stratification tool for patients at risk of aortic dissection and rupture.

Background Valve repair for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings is characterized by high IMR recurrence rates. Patient-specific preoperative imaging-based risk stratification for recurrent IMR would optimize results. We sought to determine if pre-repair three-dimensional (3D) echocardiography combined with a novel valve modeling algorithm would be predictive of IMR recurrence 6 months after repair. Methods Intraoperative transesophageal real-time 3D echocardiography was performed in 50 patients undergoing undersized ring annuloplasty for IMR (and in 21 patients with normal mitral valves). A customized image analysis protocol was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥grade 2) was assessed with two-dimensional transthoracic echocardiography 6 months after repair. Results Preoperative annular geometry was similar in all IMR patients; and preoperative leaflet tethering was significantly higher in patients with recurrent IMR (n=13) as compared with patients in whom IMR did not recur IMR (n=37) (tethering index 3.91±1.01 vs. 2.90±1.17, P=0.008; tethering angles of A3 (23.5±8.9° vs. 14.4± 11.4°, P=0.012), P2 (44.4±8.8° vs. 28.2±17.0°, P=0.002), and P3 (35.2±6.0° vs. 18.6±12.7°, P<0.001)). Multivariate logistic regression analysis revealed preoperative P3 tethering angle as an independent predictor of IMR recurrence with an optimal cut-off value of 29.9° (AUC 0.92, 95%CI 0.84–1.00, P<0.001). Conclusions 3D echocardiography combined with valve modeling is predictive of recurrent IMR. Preoperative regional leaflet tethering of segment P3 is a strong independent predictor of IMR recurrence after undersized ring annuloplasty. In patients with a preoperative P3 tethering angle ≥29.9° chordal-sparing valve replacement rather than valve repair should be strongly considered.

Background Proponents of flexible annuloplasty rings have hypothesized that such devices maintain annular dynamics. This hypothesis is based on the supposition that annular motion is relatively normal in patients undergoing mitral valve repair. We hypothesized that mitral annular dynamics are impaired in ischemic mitral regurgitation (IMR) and myxomatous mitral regurgitation (MMR). Methods and Results Philips iE33 echocardiographic module and X7-2t probe were used to acquire full volume rt-3DTEE loops in 11 normal subjects, 11 patients with IMR and 11 patients with MMR. Image analysis was performed using Tomtec Image Arena -4D-MV Assessment© - 2.1 (Munich, Germany). A midsystolic frame was selected for the initiation of annular tracking using the semi-automated program. Continuous parameters were normalized in time to provide for uniform systolic and diastolic periods. Both IMR (9.98±155 cm2) and MMR annuli (13.29±3.05 cm2) were larger in area than normal annuli (7.95±1.40 cm2) at midsystole. In general, IMR annuli were less dynamic than controls. In MMR, annular dynamics were also markedly abnormal with the mitral annulus dilating rapidly in early systole in response to rising ventricular pressure. Conclusions In both IMR and MMR, annular dynamics and anatomy are abnormal. Flexible annuloplasty devices used in mitral valve repair are, therefore, unlikely to result in either normal annular dynamics or normal anatomy.

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Objective Whereas uncomplicated acute type B aortic dissections are often medically managed with good outcomes, a subset develop subacute or chronic aneurysmal dilation. We hypothesized that computational fluid dynamics (CFD) simulations may be useful in identifying patients at risk for this complication. Methods Patients with acute type B dissection complicated by rapidly expanding aortic aneurysms (N = 7) were compared with patients with stable aortic diameters (N = 7). Three-dimensional patient-specific dissection geometries were generated from computed tomography angiography and used in CFD simulations of pulsatile blood flow. Hemodynamic parameters including false lumen flow and wall shear stress were compared. Results Patients with rapid aneurysmal degeneration had a growth rate of 5.3 ± 2.7 mm/mo compared with those with stable aortic diameters, who had rates of 0.2 ± 0.02mm/mo. Groups did not differ in initial aortic diameter (36.1 ± 2.9 vs 34.4 ± 3.6 mm; P = .122) or false lumen size (22.6 ± 2.9 vs 20.2 ± 4.5 mm; P = .224). In patients with rapidly expanding aneurysms, a greater percentage of total flow passed through the false lumen (78.3% ± 9.3% vs 56.3% ± 11.8%; P = .016). The time-averaged wall shear stress on the aortic wall was also significantly higher (12.6 ± 3.7 vs 7.4 ± 2.8 Pa; P = .028). Conclusions Hemodynamic parameters derived from CFD simulations of acute type B aortic dissections were significantly different in dissections complicated by aneurysm formation. Thus, CFD may assist in predicting which patients may benefit from early stent grafting.