Cytokines profile of reverse cardiac remodeling following transcatheter aortic valve replacement.

OBJECTIVE: Previous studies have suggested that cytokines and growth factors may predict ventricular recovery following aortic valve replacement (AVR). The primary objective of this study was to identify cytokines that predict ventricular recovery following transcatheter AVR (TAVR). METHODS: We prospectively enrolled 121 consecutive patients who underwent TAVR. Standard echocardiographic assessment at baseline, 1-month and 1-year after TAVR included left ventricular (LV) mass index (LVMI) and global longitudinal strain (GLS). Blood samples were obtained at the time of the procedure to measure cytokines using a 63-plex Luminex platform. Partial least squares-discriminant analysis was performed to identify cytokines associated with ventricular remodeling and function at baseline as well as 1 year after TAVR. RESULTS: The mean age was 84 ±â€¯9 years, with a majority of male subjects (59%), a mean LVMI of 120.4 ±â€¯45.1 g/m2 and LVGLS of -13.0 ±â€¯3.2%. On average, LV mass decreased by 8.1% and GLS improved by 20.3% at 1 year following TAVR. Among cytokines assayed, elevated hepatocyte growth factor (HGF) emerged as a common factor significantly associated with worse baseline LVMI and GLS as well as reduced ventricular recovery (p < 0.005). Other factors associated with ventricular recovery included a select group of vascular growth factors, inflammatory mediators and tumor necrosis factors, including VEGF-D, ICAM-1, TNFß, and IL1ß. CONCLUSION: We identified a network of cytokines, including HGF, that are significantly correlated with baseline LVMI and GLS, and ventricular recovery following TAVR.

Atrial Fibrillation is Associated with Increased Pacemaker Implantation Rates in the Placement of AoRTic Transcatheter Valve (PARTNER) Trial.

Atrial fibrillation (AF) is associated with worse outcomes in many cardiovascular diseases. There are few data examining pacemaker implantation rates and indications in patients with AF who undergo transcatheter aortic valve replacement (TAVR). To examine the impact of AF on the incidence of and indications for pacemakers in patients undergoing TAVR, we evaluated data of 1723 patients without pre-existing pacemakers who underwent TAVR in the Placement of AoRTic TraNscathetER Valve (PARTNER) trial. Permanent pacemaker implantation rates and indications were compared in groups based on baseline and discharge heart rhythm: sinus rhythm (SR) vs. AF. 1211 patients manifested SR at baseline/SR at discharge (SR/SR), 105 SR baseline/AF discharge (SR/AF), and 407 AF baseline/AF discharge (AF/AF). Patients who developed and were discharged with AF (SR/AF) had the highest rates of pacemaker implantation at 30 days (13.7% SR/AF vs. 5.4% SR/SR, p=0.0008 and 5.9% AF/AF, p=0.008) and 1 year (17.7% SR/AF vs. 7.1% SR/SR, p=0.0002 and 8.1% AF/AF, p=0.0034). Conversion from SR to AF by discharge was an independent predictor of increased pacemaker implantation at 30 days (HR 2.19 vs. SR/SR, 95% CI 1.23-3.93, p=0.008) and 1 year (HR 1.91 vs. SR/SR, 95% CI 1.33-3.80). Pacemaker indications differed between groups, with relatively more implanted in the AF groups for sick sinus syndrome (SSS) versus AV block. In conclusion, conversion to AF is an independent predictor of permanent pacemaker implantation in TAVR patients. Indications differ depending on heart rhythm, with patients in AF manifesting clinically significant tachy-brady syndrome versus AV block.

Descending aortic replacement after Nuss for pectus excavatum in a Marfan patient-Case report.

INTRODUCTION: The Nuss procedure for pectus excavatum (PE) repair has been successfully performed in Marfan syndrome (MFS) patients however there is concern for future risk of aortic dilation/rupture and need for emergent access with support bars in place. CASE PRESENTATION: We present a 45 year-old male with MFS that required descending aortic replacement shortly after modified Nuss repair. DISCUSSION: The majority of MFS patients have severe PE and repair with the Nuss procedure is not uncommon. The risk for life threatening aortic dilation, dissection, or rupture in such patients is a concern when utilizing this technique. Our work has been reported in line with the CARE criteria. CONCLUSION: Nuss repair should be considered in MFS patients with technique modifications and careful consideration of future risk of aortic dilation and rupture.

Multiple mitral leaflet contractile systems in the beating heart.

Mitral valve closure may be aided by contraction of anterior leaflet (AL) cardiac myocytes located in the annular third of the leaflet. This contraction, observed as a stiffening of the annular region of the AL during isovolumic contraction (IVC), is abolished by beta-blockade (ßB). Sub-threshold rapid pacing in the region of aorto-mitral continuity (STIM) also causes AL stiffening, although this increases the stiffness of the entire leaflet during both IVC and isovolumic relaxation (IVR). We investigated whether these contractile events share a common pathway or whether multiple AL contractile mechanisms may be present. Ten sheep had radiopaque-markers implanted: 13 silhouetting the LV, 16 on the mitral annulus, an array of 16 on the AL, and one on each papillary muscle tip. 4-D marker coordinates were obtained from biplane videofluoroscopy during control (C), ßB (esmolol) and during ßB+STIM. Circumferential and radial stiffness values for three AL regions (Annular, Belly, and free-Edge), were obtained from inverse finite element analysis of AL displacements in response to trans-leaflet pressure changes during IVC and IVR. ßB+STIM increased stiffness values in all regions at both IVC and IVR by 35 ± 7% relative to ßB (p<0.001). Thus, even when AL myocyte contraction was blocked by ßB, STIM stiffened all regions of the AL during both IVC and IVR. This demonstrates the presence of at least two contractile systems in the AL; one being the AL annular cardiac muscle, involving a ß-dependent pathway, others via a ß-independent pathway, likely involving valvular interstitial cells and/or AL smooth muscle cells.

Stress-strain behavior of mitral valve leaflets in the beating ovine heart.

Excised anterior mitral leaflets exhibit anisotropic, non-linear material behavior with pre-transitional stiffness ranging from 0.06 to 0.09 N/mm(2) and post-transitional stiffness from 2 to 9 N/mm(2). We used inverse finite element (FE) analysis to test, for the first time, whether the anterior mitral leaflet (AML), in vivo, exhibits similar non-linear behavior during isovolumic relaxation (IVR). Miniature radiopaque markers were sewn to the mitral annulus, AML, and papillary muscles in 8 sheep. Four-dimensional marker coordinates were obtained using biplane videofluoroscopic imaging during three consecutive cardiac cycles. A FE model of the AML was developed using marker coordinates at the end of isovolumic relaxation (when pressure difference across the valve is approximately zero), as the reference state. AML displacements were simulated during IVR using measured left ventricular and atrial pressures. AML elastic moduli in the radial and circumferential directions were obtained for each heartbeat by inverse FEA, minimizing the difference between simulated and measured displacements. Stress-strain curves for each beat were obtained from the FE model at incrementally increasing transmitral pressure intervals during IVR. Linear regression of 24 individual stress-strain curves (8 hearts, 3 beats each) yielded a mean (+/-SD) linear correlation coefficient (r(2)) of 0.994+/-0.003 for the circumferential direction and 0.995+/-0.003 for the radial direction. Thus, unlike isolated leaflets, the AML, in vivo, operates linearly over a physiologic range of pressures in the closed mitral valve.

Regional stiffening of the mitral valve anterior leaflet in the beating ovine heart.

Left atrial muscle extends into the proximal third of the mitral valve (MV) anterior leaflet and transient tensing of this muscle has been proposed as a mechanism aiding valve closure. If such tensing occurs, regional stiffness in the proximal anterior mitral leaflet will be greater during isovolumic contraction (IVC) than isovolumic relaxation (IVR) and this regional stiffness difference will be selectively abolished by beta-receptor blockade. We tested this hypothesis in the beating ovine heart. Radiopaque markers were sewn around the MV annulus and on the anterior MV leaflet in 10 sheep hearts. Four-dimensional marker coordinates were obtained from biplane videofluoroscopy before (CRTL) and after administration of esmolol (ESML). Heterogeneous finite element models of each anterior leaflet were developed using marker coordinates over matched pressures during IVC and IVR for CRTL and ESML. Leaflet displacements were simulated using measured left ventricular and atrial pressures and a response function was computed as the difference between simulated and measured displacements. Circumferential and radial elastic moduli for ANNULAR, BELLY and EDGE leaflet regions were iteratively varied until the response function reached a minimum. The stiffness values at this minimum were interpreted as the in vivo regional material properties of the anterior leaflet. For all regions and all CTRL beats IVC stiffness was 40-58% greater than IVR stiffness. ESML reduced ANNULAR IVC stiffness to ANNULAR IVR stiffness values. These results strongly implicate transient tensing of leaflet atrial muscle during IVC as the basis of the ANNULAR IVC-IVR stiffness difference.

Multiplanar visualization in 3D transthoracic echocardiography for precise delineation of mitral valve pathology.

A novel multiplanar reformatting (MPR) technique in three-dimensional transthoracic echocardiography (3D TTE) was used to precisely localize the prolapsed lateral segment of posterior mitral valve leaflet in a patient symptomatic with mitral valve prolapse (MVP) and moderate mitral regurgitation (MR) before undergoing mitral valve repair surgery. Transesophageal echocardiography was avoided based on the findings of this new technique by 3D TTE. It was noninvasive, quick, reproducible and reliable. Also, it did not need the time-consuming reconstruction of multiple cardiac images. Mitral valve repair surgery was subsequently performed based on the MPR findings and corroborated the findings from the MPR examination.

Isolated giant cell myocarditis in the atrium: an incidental finding?

Giant cell myocarditis (GCM) is an uncommon disorder that affects ventricular myocardium causing severe left ventricular dysfunction and ventricular arrhythmias. We report a case of GCM that only affected the atrium sparing the ventricle.