The MitraClip procedure represents a cutting edge way to fix a leaky mitral valve. For a broad overview of the procedure and the type of patients who need it, see our article The MitraClip – Treatment for a Leaky Heart Valve. The following article is meant for all levels of those wishing to learn about the details of the MitraClip procedure itself. It will be useful for patients who simply want to know more about the procedure, but because the article goes in to great depth, it will also be useful for advanced structural heart specialists wishing to learn the technical aspects of the MitraClip procedure.
The Mitraclip Procedure for Severe Mitral Regurgitation
The image below shows severe mitral regurgitation, which is the leaky mitral valve.
Getting Access to the Vein of the Leg
A small needle is used to obtain access to the femoral vein. This is done under fluoroscopic and ultrasound guidance usually as seen in fluoro image 1. A wire being passed through the needle in to the vein in fluoro image 2. Tubes that the procedure is performed through are then passed over wires and in to the vein as required.
Trans-septal Puncture and MitraClip Guide Catheter Advancement In to the Left Atrium
What is a Trans-septal Puncture?
The MitraClip procedure is performed through a tube that is inserted the veins of the leg. To get to the mitral valve we have to go up the vein to the right side of the heart, and then puncture through the membrane that separates the left and right chambers of the heart known as the intra-atrial septum. This is known as a Trans-septal puncture.
The Most Critical Step in the Whole Procedure
Many people would say that this is the most critical step in the MitraClip procedure. An optimally positioned Trans-septal puncture will not only markedly increase chances of success but it will reduce the chance of complication. A poorly positioned Trans-septal puncture can add hours to a MitraClip procedure and lead to the need for shortcuts that could have been avoided. If the Trans-septal puncture is felt to be in the wrong position then rather than simply proceeding, the Trans-septal system should be retracted and the puncture re-performed in a more appropriate position.
Ideal Puncture Site
The Mitraclip delivery system is a large and bulky device when compared to any other device used in the left atrium. Positioning of the device above the valve relies on using a series of levers and knobs that require adequate working space and height above the valve to allow steering. In general we prefer a high and posterior position for the puncture. The puncture should be in the region of 4cm above the mitral annular plane to allow for an adequate working space. The puncture should be relatively posterior to allow grasping of the leaflets in the plane of coaptation of the mitral valve. No matter how tempting, it is critical not to use a patent foramen tunnel to obtain left atrial access.
Imaging Guidance for Transseptal
Fluoroscopic and echocardiographic guidance can be used in guiding trans-septal puncture in general. In the clip procedure it is essentially echo guided as exact positioning is critical and cannot be done with fluoroscopy.
Fluoroscopy is used to place a guide wire in the superior vena cava. Over this guidewire a sheath is placed in the superior vena cava. The wire is removed and the trans-septal needle advanced to almost the tip of the sheath dilator. The sheath is torqued until the flange on the handle is in the 4-5 o’clock position, thus posterior, in the direction of the septum.