Introduction
Paravalvular prosthetic leak (PVL) occurs in 6% to 15% of surgical prosthetic valves or annuloplasty rings secondary to degeneration and loss of integrity of the annular tissue. Moderate-to-severe PVL is associated with increased morbidity and mortality if left untreated. , PVL is more common with mitral prostheses and use of continuous sutures or sutures without pledgets. , Patients with chronic mitral PVL usually present with clinical heart failure related to increased volume in the noncompliant left atrium (LA) and left ventricle (LV) over time. Right-sided heart failure can develop due to an increase in pulmonary artery pressure. Hemolytic anemia is also frequently seen in mitral PVL due to turbulent flow and increased shear stress on the red blood cells leading to fragmentation as they cross the paravalvular defects. Patients with coexisting iron- or folate-deficiency anemia are more prone to hemolysis due to red blood cell fragility and more turbulent flow through the defect in the setting of high cardiac output.
Indications for paravalvular leak closure
| IIa | B | Percutaneous repair of paravalvular regurgitation is reasonable in patients with prosthetic heart valves and intractable hemolysis or New York Heart Association (NYHA) class III/IV heart failure who are at high risk for surgery and have anatomic features suitable for catheter-based therapy when performed in centers with expertise in the procedure |
American College of Cardiology/American Heart Association (ACC/AHA) valve guidelines call for percutaneous PVL closure in patients with intractable hemolysis and severe heart failure symptoms who are at high risk for surgical intervention, if they have suitable anatomy for a catheter-based approach. Patients with clinically significant mitral PVL have already undergone a previous sternotomy and usually have a moderate to high risk for surgical intervention; therefore the vast majority of these patients are offered percutaneous repair at our institution if their anatomy is suitable before consideration of redo surgery ( Fig. 17.1 ).
Contraindications for paravalvular leak closure
Important contraindications include (1) active endocarditis, (2) intracardiac thrombus or vegetation, (3) a defect involving more than one-third of annular tissue, and (4) a rocking/unstable prosthesis.
PVL closure can be performed in patients with a history of endocarditis who have negative confirmatory blood cultures after completion of an intravenous antibiotic course. Similarly, patients with a history of intracardiac thrombus can be treated with anticoagulation, and percutaneous PVL closure can be attempted after ensuring full resolution of the thrombus by cardiac imaging.
Preprocedural planning
Transthoracic echocardiogram (TTE) is usually inadequate for assessment of mitral PVL due to the presence of a shadowing artifact from the prosthesis that interferes with localizing the defect(s) and assessing Doppler flow across it. Transesophageal echocardiography (TEE) is essential for preprocedural planning, as it provides in-depth information about the atrial septum and helps rule out intracardiac thrombus or vegetations. Using TEE, the mitral annulus can be divided into eight sectors ( Fig. 17.2 ) to enhance communication between the echocardiographer and operator. , Comprehensive evaluation of the prosthesis annulus with 2D TEE can help provide the location of the defect and assess the degree of PVL. Three-dimensional TEE can further delineate the accurate location, size, shape, and circumferential extent of the defect, as well as identify the number of defects present.
Cardiac computed tomography (CT) angiography imaging can also help determine the location, size, and extent of PVL but is typically not necessary for mitral PVL, given the excellent visualization provided by TEE (in contrast to aortic PVL, where CT can provide important incremental data to TEE). CT can also help predefine the best working fluoroscopic angles during the procedure. Careful discussion between the imaging cardiologist, radiologist, and interventional cardiologist is essential in preprocedural planning to help understand the anatomy and aid in deciding the best approach and equipment needed for PVL closure.
The procedure
Mitral PVL closure is a complex procedure that requires multiple skills for successful execution, including transseptal access, catheter navigation in the LA, plug delivery and deployment, and wire snaring for creation of a wire rail. LV puncture may be necessary to create a rail system in cases with double mechanical prostheses. Table 17.1 includes some of the common equipment utilized for mitral PVL closure.
| Step | Common Equipment |
|---|---|
| Imaging | 2D to 3D transesophageal echocardiography Biplane fluoroscopy |
| Access | 14F to 20F venous sheath 6F femoral artery sheath (AV rail or retrograde approach) LV puncture needle and 4F to 6F sheath (transapical rail or retrograde approach) Proglide preclose system or figure-of-8 stich |
| Transseptal Access | 7F to 8F Mullin or SL1 dilators and sheaths Brockenbrough needle Inoue dilator and wire SafeSept or electrocautery in difficult anatomy |
| Steerable Telescoping System | 8.5 Agilis steerable sheath 6F to 7F 100-cm coronary guides 5F 125-cm multipurpose catheter Exchange-length, extra-support 0.035″ hydrophilic angled Glidewire |
| Double-Wire Technique | Multiple 0.032″ to 0.035″ extra-stiff, exchange length Amplatz guidewire Flexor Shuttle Sheath |
| Anchor Wire Technique | 0.032″ to 0.035″ extra-stiff, long exchange Amplatz guidewire Flexor Shuttle Sheath |
| Rail System | Two access sites Exchange-length, extra-support 0.035″ hydrophilic angled Glidewire Two Hemostats 6F Ensnare catheter |
| Plugs | AVP II plugs (4-16 mm) AVP IV plugs (4-8 mm) |
It is important to note that no specific devices are approved by the Food and Drug Administration (FDA) for PVL closure. The devices preferred for this procedure are the Amplatzer Vascular Plugs (AVP) (St. Jude Medical; St. Paul, MN) made of low-profile fine nitinol mesh, allowing easy deliverability through guiding catheters and sheaths. The AVP II and AVP IV are available in the United States, and the AVP III is available in Europe.
Mitral PVL closure is usually performed under general anesthesia for patient safety and comfort due to the length of the procedure and the need for intraprocedure TEE guidance. Biplane fluoroscopy is highly useful tool to facilitate 3D navigation along the mitral prosthesis annulus. The fluoroscopic views are set up at right anterior oblique and left anterior oblique-caudal angulation to provide simultaneous on side and en face views of the mitral prosthesis, respectively ( Fig. 17.3 ). To minimize radiation exposure, low-resolution biplane fluoroscopy at 7.5 frames/second is recommended. The average procedure duration is 2 to 3 hours.
Mitral PVL closure can be performed using multiple methods: (1) antegrade transseptal approach, (2) retrograde transaortic approach, and (3) retrograde transapical approach. The antegrade transseptal approach is the most commonly used technique.
Antegrade transseptal approach
Most cases of mitral PVL require ultrasound-guided 14F sheath femoral venous access to provide room to alternate between different techniques during the procedure. The access site is usually managed with the preclose technique described in Chapter 2 or with a figure-of-8 stich using an Ethibond Excel polyester suture.
Transseptal access can be performed under fluoroscopy and TEE guidance. Full heparinization is recommended as soon as transseptal access is achieved, with target activated clotting time (ACT) >300 seconds to reduce the risk of thrombus formation. Presence of a septal patch or scarred/fibrotic septal tissue is not uncommon in this patient population; therefore the use of a SafeSept transseptal guidewire (Pressure Products Medical Supplies Inc., San Pedro, CA) or electrocautery system might be helpful to increase safety during transseptal puncture. Balloon dilatation of the atrial septum over a stiff coronary wire is also occasionally required to facilitate transseptal puncture.
Once transseptal puncture is achieved, access to the LA is secured with an Inoue wire (Toray Group, USA) or 0.035″ Amplatz exchange-length extra-stiff guidewire (Cook Medical; Bloomington, IN) parked in one of the pulmonary veins. After the septum is dilated with an Inoue dilator, a steerable and flexible sheath such as the 8.5F Agilis Steerable NxT Introducer (St. Jude Medical, St. Paul, MN) is advanced in the LA. Through the steerable introducer, a coaxial telescoping system consisting of 100-cm 6F to 7F multipurpose or JR4 coronary guide and 125-cm 5F multipurpose diagnostic catheter is advanced into the LA. Larger French-size guiding catheters provide more room to deliver the larger AVP plugs needed for larger defects, but might increase the difficulty in crossing smaller defects ( Table 17.2 ). The system can be navigated and steered in 3D space to position the catheter tip in close proximity to the defect. Through the telescoping system, an exchange-length extra-support angled hydrophilic 0.035″ wire (Glidewire, Terumo Medical Corp., Somerset, NJ) is advanced and torqued to probe the defect until passage, with confirmation by 3D TEE and biplane fluoroscopy. Once the wire is positioned in a safe place (usually in the ascending aorta in the absence of a mechanical aortic prosthesis), the 5F diagnostic catheter and then the guide are advanced into the LV across the defect. The most commonly used AVP II devices are ≤12 mm and can be advanced in a 6F coronary guide system without difficulty. If larger devices or multiple devices are required in a nested fashion, the telescoping system can be exchanged for a shuttle sheath (Cook Medical, Bloomington, IN) over 0.032″ or 0.035″ Amplatz exchange-length extra-stiff guidewire looped in the LV (see the anchor wire technique section later). If crossing the defect with catheters is not possible due to a defect in anatomy or lack of support, additional techniques such as the use of an arteriovenous rail may be necessary after obtaining arterial access and snaring the exchange-length hydrophilic Glidewire.
| Catheter-Only Technique | Anchor Technique With 0.032″ or 0.035″ Wire | |||
|---|---|---|---|---|
| AVP II 6-8 mm | AVP II 10-12 mm | AVP II 6-8 mm | AVP II 10-12 mm | |
| 6F Coronary Guide | Yes | Yes | No | No |
| 7F Coronary Guide | Yes | Yes | Yes | No |
| 8F Coronary Guide | Yes | Yes | Yes | Yes |
| 4F Shuttle Sheath | Yes | No | No | No |
| 5F Shuttle Sheath | Yes | Yes | Yes | No |
| 6F Shuttle Sheath | Yes | Yes | Yes | Yes |
| 7F Shuttle Sheath | Yes | Yes | Yes | Yes |
| 8F Shuttle Sheath | Yes | Yes | Yes | Yes |
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