Role of real-time three-dimensional transesophageal echocardiography in mitral valve repair

Transcription

1 Journal of Geriatric Cardiology September 2008 Vol 5 No Clinical Research Role of real-time three-dimensional transesophageal echocardiography in mitral valve repair Cuizhen Pan 1, Xianhong Shu 1, Qiling Cao 2, Chunsheng Wang 1, Wenjun Ding 1, Haozhu Chen 1 1 Department of Echocardiography, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai , China, 2 Rush University Medical Center, Chicago, USA Background and objective Pre-operative assessment of mitral valve (MV) anatomy is essential to surgical design in patients undergoing MV repair. Although 2-dimensional (2D) echocardiography provides precise information regarding MV anatomy, RT-3D TEE could increase the understanding of MV apparatus and individual scallop identification. We aimed to investigate the value of RT- 3DTEE in MV repair. Methods RT-3DTEE was performed in six patients with mitral valve prolapse (MVP) by using Philips IE33 with X7-2t probe. Preoperative RT-3DTEE studies were compared with surgical findings in patients undergoing surgical mitral valve repair, and quantitative evaluation was performed by QLab 6.0 software before and after surgical mitral valve repair. Results RT- 3DTEE could display dynamic morphology of MV, the location of prolapse, and spatial relation to the surrounding tissue. It could provide surgical views of the valves and the valvular apparatus. These results were consistent with surgical findings. The quantitative evaluation before and after surgical MV repair indicated that anterolateral to posteromedial diameter of annulus, anterior to posterior diameter of annulus, perimeter of annulus, and area of annulus in projection plane were significantly smaller after operation compared with those before operation (P<0.05). The length of posterior leaflet, the area of anterior and posterior leaflet, the maximal prolapse height, the volume of leaflet prolapse and the length of coaptation in projection plane were significantly reduced after operation (P<0. 05). Conclusion RT-3DTEE is a unique new modality for rapid and accurate evaluation of mitral valve prolapse and mitral valve repair. (J Geriatr Cardiol 2008; 5: ) Key words Echocardiography; real-time; transeophageal; mitral valve repair Introduction Two-dimensional (2D) transesophageal echocardiography (TEE) is a robust diagnostic tool for evaluating mitral valve prolapse (MVP). The main limitations of this invaluable technique in practice include the high degree of expertise required and the reduction in diagnostic accuracy in the setting of complex disease, eg, bileaflet disease, presence of multiple regurgitation mechanisms, extensive valve disease, inadequate apposition without evident changes in coaptation, and commissural disease. Advances in TEE transducer and computing technology led to the introduction of real-time three-dimensional transesophageal echocardiography, which promise to overcome the shortcomings of TEE, the visualization of the cardiac valves offered by this modality is highly realistic, and relatively easy to understand, and similar to the surgeon s view of the valve. 1-3 And Qlab 6.0 software can evaluate quantitatively mitral valve annulus and leaflet before and Correspondence to: Dr SHU Xian-hong, Department of Echocardiography, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, , China (Tel: shu.xianhong@zs-hospital.sh. cn) after mitral valve repair. Therefore, the aim of this study was to investigate the value of real-time three-dimensional transesophageal echocardiography (RT-3DTEE) in mitral valve repair. Materials and methods Patients Six patients (5 males, mean age 45.7±12.6years) gave informed consent to participate in the study. All patients had transthoracic echocardiography (TTE) and RT-3DTEE before surgery and had severe mitral regurgitation (MR) based on semi-quantitative assessment. Transthoracic echocardiography (TTE) A full cross-sectional study was performed at baseline using IE33, Phililps ultrasound system. Two-dimensional measurements were made according to the recommendation of the American Society of Echocardiography. 4 LV endsystolic and LV end-diastolic volumes were determined by the modified biplane Simpson s technique and the standard formula applied to give LV ejection fraction (LVEF), and pulmonary artery systolic pressure(pasp) was measured

2 138 Journal of Geriatric Cardiology September 2008 Vol 5 No 3 by continuous wave (CW). RT-3DTEE RT-3DTEE was performed intraoperatively after induction of anesthesia and endotracheal intubation using a X7-2t probe inserted in the esophagus and connected to a Philips IE33 ultrasound. Live 3D images were acquired from a four chamber view (transducer angle of 0 ) and a two chamber view (transducer angle of ) to obtain a pyramidal data scans ( ) of mitral valve. Full volume data set was acquired from the four chamber view and the five chambers view. This method consists of the acquisition of 4 cardiac-cycle images that generates a larger and wider single pyramid of data ( ). Immediately after the acquisition of these data sets, 3D cine loops were stored in the machine. The appropriate cutting planes were used to visualize the MV from the LA and LV. By rotating the 3D images (in dynamic loops), commissural planes and individual segments of the MV were also completely visualized. RT-3DTEE evaluation included a complete standard protocol for the evaluation of the MV, 1-3 allowing a complete description of all segments of the valve. Data analysis Full-volume data set was analyzed off-line with software(qlab, Version 6.0, Philips Ultrasound), including anterolateral to posteromedial diameter of annulus ( DAlPm), anterior to posterior diameter of annulus ( DAP), annulus height (H), area of annulus in projection plane (A2D), perimeter of annulus (C3D), length of anterior leaflet (L3D Ant), Length of posterior leaflet (L3D Post), angle of anterior leaflet (θant), angle of posterior leaflet (θpost), non-planar angle of leaflet (θnpa), maximal tenting height (HTent), maximal prolapse height (HProl), area of anterior leaflet (A3DAnt), area of posterior leaflet (A3DPost), volume of the leaflets tent (VTent), volume of leaflet prolapse (VProl), aortic orifice to mitral plane angle (θ), length of coaptation in projection plane (L2DALPM). Statistical analysis Continuous variables are expressed as means ±SD, the differences between pre and post surgical MV repair were assessed using Student t test. A P value less than 0.05 was considered significant. The statistical analysis was done using SPSS for Windows (Version 11.0). Results Clinical characteristic and echocardiographic parameters Clinical characteristics of the 6 patients were listed in Table 1. Echocardiographic parameters measured by TTE were listed in Table 2. TTE TTE showed that three patients had posterior leaflet prolapse, of whom two had severe mitral valve regurgitation (MVR), and one had moderate MVR, one patient had posterior leaflet prolapse and flail with severe MVR, one patient had anterior and posterior leaflet proplases with se- Table 1 Baseline characteristics of ptients Age,y Sex AHT(mmHg) DM Kidney failure COPD Smoke(y) NYHA CHF Persistent AF Previous CVS Case1 70 M 110/80 No No No 40+ III-IV Case2 57 M 100/70 No No No 30+ III Case3 54 M 110/80 No No No 30+ II Case4 37 M 110/60 No No No 1 III Case5 28 M 130/80 No No No No II Case6 28 F 100/60 No No No No II AF, Atrial fibrillation; AHT, aterial hypertension; CHF; congestive heart failure; COPD, chronic obstructive pulmonary disease; CVS, cardiovascular surgery; NYHA, New York Heart Association. Table 2 Echocardiographic parameters in patients with mitral prolapse Age,y Sex AORD(mm) LAD(mm) LVDd(mm) LVDs(mm) LVEF(%) PASP(mmHg) Case1 70 M <30 Case2 57 M Case3 54 M Case4 37 M Case5 28 M Case6 28 F AORD:LAD:Left atrial diameter;lvdd: left ventricular diastolic diameter; LVDs: left ventricular systolic diameter; LVEF: left ventricular ejection fraction;pasp: pulmonary artery systolic pressure.

3 Journal of Geriatric Cardiology September 2008 Vol 5 No vere MVR, one patient with anterior leaflet vegetation and perforation with moderate MVR. RT-3DTEE RT-3DTEE was successful in all patients. RT-3DTEE could provide surgical views of the valve and the valvular apparatus, display dynamic morphology of MV and its spatial relation to the surrounding tissue. Prolapse of a single MV segment was present in 4 patients and 2 patients had complex disease involving two or more segments by RT3D- TEE. RT-3DTEE correctly predicted mitral prolapse localization and chordae rupture in all patients compared with surgical findings. Figure 1 showed one patient who had P2 prolapse with two ruptured chordae. Figure 2 displayed one patient had A1 prolapse and perforation. Preoperative RT- 3DTEE studies agreed with surgical findings. All patients had trace or no mitral regurgitation after operation. Quantitative analysis of Qlab 6.0 for MV annulus and leaflet Anterolateral to posteromedial diameter of annulus, anterior to posterior diameter of annulus, perimeter of annulus, and area of annulus in projection plane after operation were significantly smaller than those before operation (P<0.05). The length of posterior leaflet, the area of anterior and posterior leaflet, the maximal prolapse height, the volume of leaflet prolapse and the length of coaptation in projection plane were significantly reduced after operation (P<0.05) (Figure 3 and Table 4). Discussion Transesophageal echocardiography (TEE) is an essential tool for all the cardiovascular surgeries. 5-7 It plays many roles intraoperatively including confirmation of preoperative diagnosis, guiding cannulation for cardiopulmonary bypass, monitoring myocardial contractility as well as loading conditions, helping the surgeon to evaluate residual intracardiac air after cardiotomy, and ensuring successful surgical results after coming off from cardiopulmonary bypass. However, two-dimensional TEE has limitations, especially in the diagnosis of more complex valves for which repair is more difficult. Figure 3 Prolapse of the middle scallop posterior leaflet (P2) before MV repair (left) ; normal MV post MV repair (right) Figure 1 A RT-3DTEE displays posterior leaflet middle segment (P2) prolapse, and two ruptured chordae; B concordance of RT-3DTEE with operation ;C the specimen of posterior leaflet prolapse and two ruptured chordae. Figure 2 A RT-3DTEE displays anterior leaflet medial segment (A1) prolapse, and perforation; B concordance of RT-3DTEE with operation; C the specimen of anterior leaflet prolapse and perforation.

4 140 Journal of Geriatric Cardiology September 2008 Vol 5 No 3 Annulus DAlPm(mm) ± ± DAP(mm) ± ± H(mm) 10.2 ± ± C3D(mm) ± ± A2D(mm 2 ) ± ± Leaflet L3DAnt(mm) ± ± L3DPost(mm) ± ± θant( ) ± ± θpost( ) ± ± θnpa( ) ± ± HTent(mm) 7.97 ± ± HProl(mm) 5.83 ± ± A3DAnt(mm 2 ) ± ± A3DPost(mm 2 ) ± ± VTent(ml) 3.01 ± ± VProl(ml) 0.97 ± ± Aortic-Mitral θ( ) ± ± Coaptation Table 3 Results of MV annulus and leaflet and aortic-mitral and coaptation before and after MV repair Pre-operation Post-operation p value L2DALPM(mm) ± ± DAlPm:anterolateral to posteromedial diameter of annulus; DAP: anterior to posterior diameter of annulus; H: annulus height; A2D: area of annulus in projection plane; C3D: perimeter of annulus; L3DAnt: length of anterior leaflet; L3DPost: length of posterior leaflet; θant: angle of anterior leaflet; θpost: angle of posterior leaflet; θnpa: non-planar angle of leaflet; HTent : maximal tenting height; HProl: maximal prolapse height; A3DAnt: area of anterior leaflet; A3DPost: area of anterior leaflet; VTent: volume of the leaflets tent; VProl: volume of leaflet prolapse; θ : Aortic orifice to mitral plane angle; L2DALPM: length of coaptation in projection plane Degenerative valve disease is one of the most common cause of MR. A detailed anatomic evaluation of the MV is essential to successful surgical repair. Although 2- dimensional echocardiography provides information regarding MV anatomy, RT-3DTEE could increase the understanding of MV apparatus and individual scallop identification. RT-3DTEE uses a novel matrix phased-array transducer which can obtain a pyramidal volume and allow cardiac structures to be examined en face. Moreover, RT-3DTEE is less dependent on the operator, because the probe does not require precise movements or experience to locate the segments. 3D images can be easily interpreted by a nonexpert observer, as previously reported. 8,9 Our study demonstrates that RT-3DTEE is a feasible technique for the precise anatomic localization of MV prolapsing segments, and measurement of the mitral annulus and leaflet area, which is very useful in planning the surgical intervention. After the prolapsed segments were resected and artificial annulus was used, the annulus diameter, the area of leaflet, and the length of coaptation are decreased by RT-3DTEE. The RT-3DTEE results showed a very high agreement with surgical findings in the current study. In summary, RT-3DTEE is a great advance in the preoperative evaluation of MV prolapse, and can offer images that are easier to interpret, thereby is important in assisting decisions on the reparability of the valve and the surgical approach. Reference 1. Sharma R, Mann J, Drummond L, et al. The evaluation of realtime 3-dimensional transthoracic echocardiography for the preoperative functional assessment of patients with mitral valve prolapse: a comparison with 2-dimensional transesophageal echocardiography. J Am Soc Echocardiogr 2007, 20(8): Fabricius AM, Walther T, Falk V, et al. Three-dimensional echocardiography for planning of mitral valve surgery:current applicability Ann Thorac Surg 2004,78(2): De Simone R, Glombitza G, Vahl CF, et al. Three-dimensional color Doppler flow reconstruction and its clinical applications.

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