Giuseppe Saracino

Three-Dimensional Geometry of the Tricuspid Annulus in Healthy Subjects and in Patients With Functional Tricuspid Regurgitation A Real-Time, 3-Dimensional Echocardiographic Study

Background— Most rings currently used for tricuspid valve annuloplasty are formed in a single plane, whereas the actual tricuspid annulus (TA) may have a nonplanar or 3-dimensional (3D) structure. The purpose of this study was therefore to investigate the 3D geometry of the TA in healthy subjects and in patients with functional tricuspid regurgitation (TR). Methods and Results— This study consisted of 15 healthy subjects and 16 patients with functional TR who had real-time 3D echocardiography. With our customized software, 8 points along the TA were determined with the rotated plane around the axis at 45°intervals. The TA was traced during a cardiac cycle. The distance between diagonals connecting 2 points was measured. The height was defined as the distance from the plane determined by least-squares regression analysis at all 8 points. Both the maximum (7.5±2.1 versus 5.6±1.0 cm2/m2) and minimum (5.7±1.3 versus 3.9±0.8 cm2/m2) TA areas in patients with TR were larger than those in healthy subjects (both P<0.01). Healthy subjects had a nonplanar-shaped TA with homogeneous contraction. The posteroseptal portion was the lowest toward the apex from the right atrium, and the anteroseptal portion was the highest. In patients with functional TR, the TA was dilated in the septal to lateral direction, resulting in a more circular shape than in healthy subjects. A similar 3D pattern was observed in patients with TR, but it was more planar than that in healthy subjects. Conclusions— Real-time 3D echocardiography showed a complicated 3D structure of the TA, which appeared to be different from the “saddle-shaped” mitral annulus, suggesting an annuloplasty for TR different from that for mitral regurgitation.

Local dysfunction and asymmetrical deformation of mitral annular geometry in ischemic mitral regurgitation: A novel computerized 3D echocardiographic analysis

Objective: Most studies of the pathogenesis of functional mitral regurgitation (MR) have focused on alterations in ventricular function and geometry. We used a novel 3D echocardiographic method to assess abnormalities in mitral annular (MA) geometry and motion in patients with ischemic MR (IMR) and compared these data to those obtained from normal subjects and from patients with MR caused by dilated cardiomyopathy (DMR). Methods: Real time 3D echo was performed in 12 normal subjects, 25 with IMR, and 14 with DMR. Eight points along the saddle‐shaped MA were identified using our software at systole and diastole. From these eight points, four annular diameters at each cardiac phase were determined. Annular motion was assessed by measuring local displacement (LD) of a given point between systole and diastole. Results: Annular motion was different between groups: IMR had smaller LD in posterior MA segments than did normals (2.6 ± 1.1 vs 4.8 ± 1.9 mm, P < 0.01), while DMR had globally reduced LD. In IMR systolic MA dilatation was striking in the anterior–posterior (diameter; IMR vs controls, 28.3 ± 3.5 vs 22.5 ± 2.2 mm, P< 0.05) and anterolateral–posteromedial (31.7 ± 3.5 vs 25.1 ± 2.2 mm, P < 0.05) directions; in IMR, systolic MA diameters in these two directions correlated with MR severity (P = 0.02) . MA dilatation occurred globally in DMR. Conclusion: This novel 3D echo method demonstrated that MA motion and dilatation were asymmetric in IMR and symmetric in DMR. These differences in MA geometry and motion may aid in the development of distinct new therapies for IMR and DMR.

Dynamic Change of Mitral Annular Geometry and Motion in Ischemic Mitral Regurgitation Assessed by a Computerized 3D Echo Method

Objective: In patients with ischemic mitral regurgitation (IMR), we assessed dynamic changes in mitral annular geometry and motion during the cardiac cycle, and examined their association with the severity of IMR, using our computerized three‐dimensional (3D) echo method. Methods: Real‐time 3D echo was performed in 12 normal controls and 25 patients with IMR. The saddle‐shaped annulus was reconstructed in every 3D volume/frame during a cardiac cycle. For each 3D volume/frame, we assessed the mitral annular area (MAA) and the annular contraction that was expressed as the percentage of the largest MAA accounted for by the change in MAA from largest to smallest calculated value. Results: In IMR patients, the minimum MAA occurred in late‐systole, while it occurred in early‐systole in the controls. IMR patients had a larger minimum MAA (6.7 ± 1.3 vs. 3.6 ± 0.8 cm2, P < 0.001) and reduced annular contraction (23.0 ± 6.5 vs. 42.6 ± 7.0%, P < 0.001) when compared to controls. Both minimum MAA and annular contraction had significant correlations with IMR severity (r = 0.67 and r = 0.78, P < 0.001 for both). Conclusion: The contraction of the dilated mitral annulus occurred in late‐systole in patients with IMR. The alterations of annular geometry and motion may be associated with the development of IMR. (Echocardiography 2010;27:1069‐1077)

A novel system for the assessment of mitral annular geometry and analysis of 3D motion of the mitral annulus from 3D echocardiography

Red-time 30 echocardiography (RT3DE) allows noninvasive evuluation of mitml unnulur 3D geometry. In [his study, we propuse a novel cmmpurrrized niethod for the assessment of mitral annular (MA) geometry and anulysis of MA motion through [he cardiac cycle. We upplied this technique to examine diflerrnces between normal subjects and putients with ischemic mitral regurgitation (IMR). The algorithm was evaluated using five suddle-shrryed MA phentoms and then applied to both normal subjects und putienls with IMR. Strong ngrerment between the rstimuted ond iicfual angle ofthe MA phantoms wus observed (y=0.99x+1.5. r=0.87, p<0.001, mean diflermce 2.66±10.9). in [he clinical study, non-planarity angle ut end-systole (ES) was significuntly grenter in IMR vs normal subjem (135±9.2 vs. 129.3±3.1, p<0.03). In ull cuses, MA wiis less plunur UI ES thun ED. In IMR, MA wiis diiufed (943±83 vs. 769±34 mm2, pc0.005) Lind moiion of postt.rtrlutrm1 MA wtis sipificuntly rediiced (7.3±1.3 vs 16.0±1.1 mm p<0.001). This upproach run determine unique 30 descrip fors of MA geometry !ha[ may provide infrrmatian about puthophys.iologic ahunges in purienfs wirh IMR.

Fast interactive real-time volume rendering of real-time three-dimensional echocardiography: an implementation for low-end computers

Real-time three-dimensional echocardiography (RT3DE) is an innovative cardiac imaging modality. However, partly due to lack of user-friendly software, RT3DE has not been widely accepted as a clinical tool. The object of this study was to develop and implement a fast and interactive volume renderer of RT3DE datasets designed for a clinical environment where speed and simplicity are not secondary to accuracy. Thirty-six patients (20 regurgitation, 8 normal, 8 cardiomyopathy) were imaged using RT3DE. Using our newly developed software, all 3D data sets were rendered in real-time throughout the cardiac cycle and assessment of cardiac function and pathology was performed for each case. The real-time interactive volume visualization system is user friendly and instantly provides consistent and reliable 3D images without expensive workstations or dedicated hardware. We believe that this novel tool can be used clinically for dynamic visualization of cardiac anatomy.

Novel time-varying 3D display of wall motion, strain, strain rate and torsion for LV function assessment

Advanced post processing of the standard acquisitions of echocardiographic data (i.e. 3 parallel short-axis views and 3 rotational long axis views) results in a total of 72 time-varying traces of segmental linear strains and 18 traces of segmental rotational data. If one separates the signal into endo, mid, and epicardial myocardial layers, a staggering 246 time-varying traces are available. The synthesis of this amount of data is extremely difficult. Our goal was to develop tools that can visualize this complex dataset in a single representation and use these tools to assess LV function in subjects to examine characteristic patterns.

3D analysis of transmural myocardial strain from sonomicrometric crystals in the open chest dog

Interest in left ventricular (LV) mechanics has recently focused on detailed 3D analysis of LV deformations. Our goal is to investigate transmural strain variability within the normal ventricle and during the early stages of ischemia using sonomicrometric crystals implanted into canine LV wall. In this study 3 open chest dog models were implanted in a two-tetrahedron configuration with three crystals on the epicardial surface, three on the endocardial surface and one in the LV midwall. Our algorithm numerically reconstructs local ventricular 3D geometry and mechanics including radial, longitudinal and circumferential strain. Along with EKG, pressure-volume signals were acquired using a catheter introduced to LV from the femoral artery. Results obtained clearly illustrate a difference in strain across the myocardium. This study shows that the method can disclose important information regarding transmural variability in animal model and further investigation with different pacing and conditions could enhance understating of LV Mechanics.

Co-registration of doppler tissue synchronization imaging and computer tomography with an application to pacing and cardiac resynchronization therapy

Dyssynchronous myocardial contraction can be treated with surgical implant of a pacing device. Integrated information of coronary anatomy and mechanical delay may be extremely beneficial to success of the implant but it is not available in current cardiac imaging modalities. The objective of this study is to investigate the feasibility of a point-merge co-registration approach to overcome the limitation. This study shows that our method is a reliable and fast tool useful not only to attain optimal left ventricular implantation site but also to better select patients that undergo cardiac resynchronization therapy.

Wireless echocardiographic image acquisition and review

Digital echocardiography has altered clinical workflow and improved patient care. While network performance is critical for data transfers, bandwidth tradeoffs might be acceptable to allow access to data outside of the echo laboratory. In this study, we examined the ability to use portable ultrasound in a wireless environment to provide real-time echo monitoring. Video output of a handheld machine transmitted over a wireless infrastructure in which various parameters were modulated to assess their impact In this testbed configuration, we are able to transmit full color echocardiographic images via 802.11b to a handheld computer with a resolution of 320/spl times/240 pixels at 15 fps. While a major strength of ultrasound is its portability, wired network connectivity creates limitations on effective data management The growth of handheld echocardiographic devices further emphasizes the need for wireless connectivity beyond the boundaries of the hospital.