The mitral valve (MV) is one of the most challenging structures of the heart with its complex saddle-shaped annulus and multi-scalloped and indented leaflets. Mitral valve regurgitation (MR) and its surgical correction is a Class I indication for two-dimensional (2D) and color Doppler echocardiography. It is an invaluable tool in assessing ventricular function and hemodynamics sensu latu, and systematically etiology, pathophysiology, diagnosis and follow-up of surgical correction of the MV in the perioperative phase sensu stricto.  transthoracic cardiac ultrasound is the standard for the preoperative and postoperative assessments

Dynamic evaluation of the mitral valve is the cornerstone of correct management. A static approach, as is performed during abduction, could hardly deliver an optimal picture for a complicated structure as the mitral valve is functioning. MRI permits a dynamic approach, though this technique lacks mobility for evaluation of the critically ill. Cardiac ultrasound delivers a bedside dynamic approach, including motion of the leaflets, evaluation of the coaptation of the leaflet edges and the level of coaptation in relation to the mitral annulus, besides the function of related ventricular wall segments.

Knowledge on proper functioning of the mitral valve during both systole and diastole could be derived from a thorough comprehension of left heart physiology. It relies on the developing pressure gradient between the left atrium and the left ventricle (LV) throughout the cardiac cycle, governing the opening and closure of the mitral valve. Once left atrial pressure surmounts left ventricular diastolic pressure, the valve opens. After an early filling wave (E on transmitral Doppler), left atrial contraction induces a second flow wave of oxygenated blood (A wave). Immediately after this flow wave, left atrial pressure declines below LV pressure, resulting in MV closure. Closure and opening of the MV are governed by both interplay of pressure gradients, which vary throughout the cardiac cycle, and the balance between closing forces and the tethering forces, as a consequence of the tension built up by the subvalvular apparatus and the contracting adjacent wall segments.

Carpentier classification Type I mitral valve regurgitation is due to a perforated leaflet or incomplete mitral leaflet closure due to annular dilation. In the case of annular dilatation, the leaflets and the subvalvular apparatus are usually normal in morphology. The first step in evaluating for type I mitral valve involves multiplane 2D transesophageal echocardiogram . One must recognize that one of the etiologies of the MR in this group is when the leaflets are usually normal but do not coapt as a result of annular dilatation. The malcoaption of the leaflets results in severe mitral regurgitation. In addition to measuring the mitral annulus to establish that the MR is indeed due to annular dilation, the echocardiographer should also measure the tricuspid annulus. There have been several studies demonstrating that the pre-surgical tricuspid annulus measurement predicts residual functional tricuspid regurgitation post mitral valve surgery. The echocardiographer should determine the amount of tricuspid regurgitation to determine if a concomitant tricuspid annuloplasty ring is warranted at the time of mitral valve surgery.

Lastly, one should also determine pulmonary artery systolic pressures since this may help in the assessment of the right ventricle post mitral valve surgery.  Maximum TR velocity should be measured to determine pulmonary artery systolic pressure. This is sometimes challenging on transesophageal echocardiogram  and maybe better appreciated on transthoracic imaging.

For the purpose of determining pulmonary artery systolic pressure we highly recommend the Linear Wireless Ultrasound Scanner SIFULTRAS-5.34 – Color Doppler. This wireless ultrasound’s technology has the greatest potential for surgical mitral valve repair. The technology allows the surgeon to immediately see the results of the repair, and provides good information on the evolution of ventricular function. This device can also be used at various locations beyond the cath lab, including the ICU, the EP lab, the OR and for ultrasound-guided procedures at the bedside. It has a superior Color Image Quality, accurate scan results, cost-Effective, small and light, easy to carry and operate for evaluation of the critically ill. A single charge can hold up to 90 minutes of successive scanning.

These assessment procedures are performed by a qualified cardiologist whose trained in ultrasound in collaboration with an ultrasound technician*

Reference: Two and three dimensional echocardiography for pre-operative assessment of mitral valve regurgitation
Non-invasive estimation of pulmonary artery systolic pressure with Doppler ultrasound