The Effect of Depth of Anesthesia on the Severity of Mitral Regurgitation as Measured by Transesophageal Echocardiography

The Early Effects on Tricuspid Annulus and Right Chambers Dimensions in Successful Tricuspid Valve Bicuspidization

BACKGROUND

It is unclear to what degree of tricuspid annulus (TA) reduction is necessary to achieve good postoperative results in surgical bicuspidization. The study aimed to evaluate TA and right heart chamber's dimensions before and after heart surgery; and to compare TA parameters assessed by different modalities.

METHODS

Forty patients underwent mitral valve surgery with or without concomitant tricuspid valve (TV) bicuspidization. Preoperative and postoperative measurements of TA dimensions were performed prospectively using two-dimensional (2D) and three-dimensional (3D) transthoracic echocardiography (TTE). Additionally, preoperative transesophageal echocardiography (TOE) was performed in the operating room prior to surgery.

RESULTS

All patients had no or mild TR immediately after surgery. There was a significant reduction in 2D and 3D parameters of the TV and right chambers in the TV bicuspidization group. However, TV leaflets' tethering parameters did not change significantly. Preoperative 3D TTE measurements were smaller than those obtained through 3D TOE in the operation room, before surgery under general anesthesia. The 2D systolic apical 4Ch diameter and the parasternal short axis diameter mainly represent the 3D minor axis of the TA and are smaller than its 3D major axis.

CONCLUSIONS

Although bicuspidization results in a one-third reduction of the TV area, tethering of the TV leaflets remains unchanged. Moreover, 3D TOE parameters of the TV under general anesthesia are larger than preoperative 3D TTE measurements. Conventional 2D measurements are insufficient for evaluating the maximum diameter of the TA.

General Anesthesia Leads to Underestimation of Regurgitation Severity in Patients With Secondary Mitral Regurgitation Undergoing Transcatheter Mitral Valve Repair

OBJECTIVES

To evaluate the effect of general anesthesia (GA) on severity of mitral regurgitation (MR) in patients undergoing transcatheter mitral valve repair (TMVR).

DESIGN

Retrospective cohort study.

SETTING

Tertiary care university hospital.

PARTICIPANTS

Fifty consecutive patients with symptomatic severe MR and extremely high surgical risk.

INTERVENTION

TMVR under GA.

MEASUREMENTS AND RESULTS

Transesophageal echocardiography was performed during the preprocedural workup under conscious sedation and during TMVR under GA. After the parameters of MR were assessed, color-flow jet area (CJA), vena contracta (VC), effective regurgitant orifice area (EROA), regurgitant volume (RVOL), three-dimensional (3D) vena contracta area (VCA), and severity of MR were compared between the two examinations. In patients with primary MR (n = 11), there were no significant differences in CJA, VC, EROA, RVOL, or 3D-VCA between pre- and intraprocedural transesophageal echocardiography. In patients with secondary MR (n = 39), GA led to significant decreases of CJA (10 ± 7 v 7 ± 3 cm², p < 0.001), VC (5.5 ± 1.6 v 4.7 ± 1.5 mm, p = 0.002), EROA (30 ± 11 v 24 ± 10 mm², p < 0.001), and RVOL (47 ± 17 v 34 ± 13 mL/beat, p < 0.001). Consequently, GA led to a downgrade of regurgitation severity classification in 44% of patients when assessed by two-dimensional analysis. When evaluated by 3D analysis, GA also led to a significant but less extensive decrease of MR (3D-VCA: 66 ± 27 v 60 ± 29 mm², p = 0.002), and subsequent downgrade of MR classification in 20% of patients.

CONCLUSIONS

GA underestimates regurgitation severity in patients with secondary, but not primary MR, undergoing TMVR. This effect must be considered when evaluating the immediate result of the procedure.

Transesophageal Echocardiographic Assessment of the Repaired Mitral Valve: A Proposed Decision Pathway

The indications for mitral valve repair extend across the entire spectrum of degenerative mitral valve disease, ranging from fibroelastic degeneration to Barlow's disease. Collaboration between the surgeon and anesthesiologist is essential for ensuring optimal results. Echocardiographic assessment of the repair can be challenging but is essential to the success of the procedure, as even mild residual mitral regurgitation can portend poor patient outcomes. In addition to determining the severity of residual regurgitation, the anesthesiologist must elucidate the mechanism of disease in order to inform appropriate re-intervention measures. Finally, there are unique complications of mitral valve surgery for the anesthesiologist to understand and assess by echocardiography. This review describes a systematic pathway for a comprehensive intraoperative assessment of the mitral valve following surgical repair.

Echocardiographic Assessment of the Mitral Valve for Suitability of Repair: An Intraoperative Approach From a Mitral Center

Intraoperative echocardiography of the mitral valve in the precardiopulmonary bypass period is an integral part of the surgical decision-making process for assessment of suitability for repair. Although there are comprehensive reviews in the literature regarding echocardiographic examination of the mitral valve, the authors present a practical stepwise algorithmic workflow to make objective recommendations. Advances in echocardiography allow for quantitative geometric analyses of the mitral valve, along with precise assessment of the valvular apparatus with three-dimensional echocardiography. In the precardiopulmonary bypass period, echocardiographers are required to diagnose and quantify valvular dysfunction, assess suitability for repair, assist in annuloplasty ring sizing, and determine the success or failure of the surgical procedure. In this manuscript the authors outline an algorithmic approach to intraoperative echocardiography examination using two-dimensional and three-dimensional modalities to objectively analyze mitral valve function and assist in surgical decision-making.

Intra-operative trans-esophageal echocardiography in heart valve disease

Peri-operative echocardiography is widely used because it provides information that significantly influences clinical/surgical management and improves outcome in patients undergoing cardiac surgery. The role of intra-operative trans-esophageal echocardiography (TEE) in valvular heart disease cannot be emphasized enough. Increasing use of newer surgical techniques-valve repairs and minimal invasive cardiac surgery also warrants intra-operative TEE. It gives us better insight into the anatomy and physiology of the valvular lesion by digital imaging. This manuscript provides an illustrative case based overview of intra operative TEE (IOTEE) in heart valve surgery.

Insufficient Leaflet Remodeling in Patients With Atrial Fibrillation

Background—

The relationship between annular dilatation caused by atrial fibrillation (AF) and mitral regurgitation (MR) remains controversial. We hypothesized that the small ratio of total leaflet area/annulus area (TLA/AA), reflecting insufficient leaflet remodeling to annular dilatation, is a main component of MR in patients with AF.

Methods and Results—

Three-dimensional transesophageal echocardiographic data of the mitral valve were analyzed in 28 AF patients with moderate or severe MR (MR group), age- and sex-matched 56 AF patients with mild or less MR (non-MR group), and 16 control subjects. AA was significantly greater in both the MR (645±126 mm 2 /m 2 , P <0.001) and non-MR groups (568±121 mm 2 /m 2 , P =0.001) compared with control subjects (444±108 mm 2 /m 2 ). However, TLA/AA was significantly smaller in the MR (1.29±0.10, P <0.001), but not in the non-MR group (1.65±0.24, P >0.99), compared with control subjects (1.70±0.29). In linear regression analysis, TLA/AA was inversely associated with the effective regurgitant orifice ( r =−0.73, P <0.001). The area under the receiver-operating-characteristics curve of TLA/AA was significantly greater than that of AA (0.95 versus 0.72, P <0.001). Multivariable analysis revealed that small TLA/AA ( P <0.001) was independently associated with significant MR, while AA was not ( P =0.26).

Conclusions—

In patients with AF, insufficient leaflet remodeling to annular dilatation, rather than crude annular dilatation, was strongly associated with the severity of MR.

Advances in percutaneous treatment of mitral regurgitation

Percutaneous techniques for the treatment of mitral regurgitation have aroused much interest in recent years. Percutaneous mitral annuloplasty can be performed indirectly by using devices implanted in the coronary sinus or directly by using a retrograde approach. However, as yet, the results of these techniques are scarce and some devices have a high complications rate. The most frequent percutaneous mitral valve repair technique consists of mitral leaflet plication by implanting 1 or more percutaneous clips (MitraClip) in an imitation of the Alfieri surgical technique. Clinical experience with this device is broader than that with any other. The MitraClip device is associated with improved mitral regurgitation in a high percentage of carefully-selected patients. However, the single randomized study performed to date (EVEREST) showed its efficacy to be less than that of surgical repair and we await the results of new randomized studies that should clarify which patient-type can benefit most from this technique. Other left ventricular remodeling devices, tendinous cord implantation, and leaflet ablation are currently undergoing preclinical development or first-in-human experimentation. Finally, the development of biological prostheses for percutaneous mitral valve replacement is at an early stage. Many promising experiments at the preclinical phase and initial experiments in humans will very probably multiply in the near future. However, the true role of this technique in treating mitral valve disease will have to be evaluated in appropriately designed randomized controlled studies.

Mechanisms of functional mitral regurgitation in ischemic cardiomyopathy determined by transesophageal echocardiography (from the Surgical Treatment for Ischemic Heart Failure Trial)

The mechanisms underlying functional mitral regurgitation (MR) and the relation between mechanism and severity of MR have not been evaluated in a large, multicenter, randomized controlled trial. Transesophageal echocardiography (TEE) was performed in 215 patients at 17 centers in the Surgical Treatment for Ischemic Heart Failure (STICH) trial. Both 2-dimensional (n = 215) and 3-dimensional (n = 81) TEEs were used to assess multiple quantitative measurements of the mechanism and severity of MR. By 2-dimensional TEE, leaflet tenting area, anterior and posterior leaflet angles, mitral annulus diameter, left ventricular (LV) end-systolic volume index, LV ejection fraction (LVEF), and sphericity index (p <0.05 for all) were significantly different across MR grades. By 3-dimensional TEE, mitral annulus area, leaflet tenting area, LV end-systolic volume index, LVEF, and sphericity index (p <0.05 for all) were significantly different across MR grades. A multivariate analysis showed a trend for annulus area (p = 0.069) and LV end-systolic volume index (p = 0.071) to predict effective regurgitant orifice area and for annulus area (p = 0.018) and LV end-systolic volume index (p = 0.073) to predict vena contracta area. In the STICH trial, multiple quantitative parameters of the mechanism of functional MR are related to MR severity. The mechanism of functional MR in ischemic cardiomyopathy is heterogeneous, but no single variable stands out as a strong predictor of quantitative severity of MR.