Transcatheter direct mitral valve annuloplasty with the Cardioband system for the treatment of functional mitral regurgitation

The Cardioband system obtained CE mark approval in October 2015. Initial clinical experiences after implantation in high-risk patients with FMR are promising with regard to feasibility, safety and efficacy. The study included 31 consecutive high-risk patients with severe FMR (mean age 71.8 ± 6.9 years). The Cardioband device was successfully implanted in all patients (31/31). A significant reduction of the mitral septolateral dimension was observed during intraoperative adjustment of the device (from 36.8 ± 4.8 to 29 ± 5.5 mm; P < 0.01). Residual MR after the implant was none or trace in 6 (21%), mild in 21 (72%) and moderate in 2 (7%) patients. Thirty-day mortality was 6.5% (2/31 patients: 1 patient died from intracranial bleeding and 1 with residual moderate MR died from multiorgan failure after mitral surgery). At 30-day follow-up, 22/25 patients had MR ≤2+ [9].

Besides MR reduction, the most significant result in terms of efficacy is the reduction of the septolateral mitral annular dimension observed after the adjustment. The majority of surgeons prefer to perform undersized annuloplasty with a complete rigid ring to address FMR. However, surgical experience suggested that the main determinant for repair durability after undersized annuloplasty in FMR is the achievement of good leaflet coaptation rather than the type of ring (a coaptation length of at least 8 mm should be obtained to ensure a durable repair), and coaptation length is strictly related to the reduction in the septolateral dimension [10, 11]. After the final adjustment, a more than 21% reduction in the septolateral dimension was observed with Caridoband, which is comparable with that obtained after surgical undersized annuloplasty with a complete ring (22% with Edwards Physio II ring and 25% with the IMR ETlogix ring) [12]. Moreover, compared with conventional surgical rings, the possibility of beating-heart adjustment of the Cardioband may allow optimizing the reduction in septolateral diameter and the final coaptation length.

The Cardioband adjustable annuloplasty system includes the implant and three main accessories:

i. The implant is a polyester sleeve with radiopaque markers spaced 8 mm apart from one another (Fig. 1A and B). The sleeve is mounted on the delivery system and the anchor deployed from the internal part. A contraction wire in the Cardioband is connected to an adjusting spool. Activating the spool enables to shorten the implant. Hence, the implant size is reversibly adjusted to the patient's needs under TEE guidance.

ii. Delivery system: the Cardioband delivery system (CDS) consists of the implant delivery system (IDS) and the 25F transseptal steerable sheath (TSS). The IDS comprises a steerable guide catheter and an implant catheter with the Cardioband implant mounted on its distal end (Fig. 1C).

iii. Implantable metal anchors and anchor delivery shafts: Implantable 6-mm long anchors of stainless steel are used to securely fix the Cardioband implant to the annulus. Between 12 and 17 anchors are implanted using a delivery shaft. The anchors are fully repositionable and retrievable until final deployment of the device.

iv. Size adjustment tool (SAT): The SAT distal tip is connected over the implant wire and is used to control the implant adjustment spool and the implant size.

We here describe the case of a 69-year-old symptomatic patient (New York Heart Association III–IV) with severe idiopathic FMR and impaired ventricular function (left ventricle ejection fraction: 29%). The reduced ventricular function and multiple concomitant pathologies (severe chronic obstructive pulmonary disease, chronic renal failure and severe pulmonary hypertension) increased the perioperative risk for conventional surgical mitral valve repair. Therefore, a transcatheter approach was suggested after ­interdisciplinary discussion in the Heart Team. Since the main mechanism of MR was annular dilatation with limited tethering in the absence of ­structural leaflet pathology, the patient was considered an ideal candidate for transcatheter annuloplasty with the Cardioband system.

Preprocedural coronary angiography showed a normal coronary status with left-sided dominance.

Preprocedural angiographic CT scan is mandatory to assess the patient's eligibility and for procedural planning predicting the optimal fluoroscopic planes to implant the anchors. Moreover, it allows the operator to rule out annular calcifications (which represent the major anatomical contraindication to Cardioband implantation), to size the length of the posterior mitral annulus, to plan the optimal location for trans-septal puncture and to assess the distance between the annulus and the left circumflex coronary artery to evaluate the potential risk of coronary injury.

In this case, significant annular calcifications were ruled out by CT scan prior to the intervention. The proper implant size of the Cardioband was selected according to the measurements of the mitral annulus on CT scan. In this specific case, CT scan showed clearly that the distance between the mitral annulus and the circumflex artery was enough to allow safe anchor implantation (Video 2).

Two femoral accesses are provided (venous and arterial). The venous access is the therapeutic access and it is pre-closed with a Proglide device. Using the arterial access, the left coronary artery is engaged with a diagnostic JL 4 catheter and a Balance coronary wire is positioned in the circumflex artery as a reference.

Trans-septal puncture is performed with the standard pull-back technique under TEE guidance. The ideal puncture location is infero-anterior. A low rather than high puncture is recommended. A Super-stiff wire is then advanced in the left superior pulmonary vein (Video 3).

The TSS is then inserted over the wire across the interatrial septum into the left atrium. This manoeuvre is performed in fluoroscopic left anterior oblique projection. In right anterior oblique projection, the TSS is steered towards the left ventricle (LV) apex to address the mitral valve in its mid-portion. Intercommissural 2D and surgical 3D views help confirming the position (Video 4).

The IDS is inserted in the TSS. The IDS comprises a steerable guide catheter and an implant catheter with the Cardioband implant mounted on its distal end. A stabilization wire is advanced through the mitral valve in the LV. Under 3D echo guidance, the guide catheter is moved towards the anterolateral commissure of the mitral valve. Subsequently, the tip of the implant catheter is placed above the anterolateral commissure. Confirmation of the proper location is obtained with 3D TEE; 2D echo assures that the tip of the implant catheter is pointing to the mitral annulus rather than to the leaflets and enables to assess the optimal angle for anchor implantation, which should enter the annular tissue perpendicularly. A left coronary angiogram is performed to assess the distance from the circumflex artery before the implant of the first anchor (Video 5).

Once the desired position is achieved, the first anchor is implanted in correspondence with the anterolateral commissure. Extra-systolic beats visible on the ECG suggest that the anchor is fixated to the LV muscular tissue. The application of the anchor is observed live on fluoroscopy. A push and pull test is performed to document a firm implantation of the anchor. If the position is correct, the anchor is released. The stabilizing wire then is removed. The next portion of the Cardioband is released up to the next radiopaque marker that turns visible (Video 6).

The implant catheter tip is then navigated to the next suggested anchoring point along the posterior annulus under transesophageal echocardiography (TEE) guidance by operating the TSS and guide catheter steering knobs. This process is repeated until reaching the last anchoring site on the posteromedial commissure. In this case, a total of 16 anchors were deployed to cover the entire length of the atrial side of the posterior mitral annulus. 

Video 7 shows the implantation of the second and third anchors. An uncut fast-forward video shows the implantation of the remaining anchors from 4th to 16th, which took 70 min.

After the implantation of the last anchor, the implant is disconnected from the IDS, which subsequently is removed. The SAT is then inserted through the TSS over the implant guide wire until its distal end reaches the adjustment spool of the implant (Video 8).

After SAT connection, the implant is contracted stepwise by clockwise rotation of the adjustment roller. Adequate reduction of MR is assessed simultaneously by TEE under beating-heart conditions. Improvement of the haemodynamic can be observed immediately [left atrium (LA) pressure decrease and V-wave changes on the monitor]. After the achievement of an appropriate implant size, the SAT is detached from the adjustment spool with the implanted Cardioband at its defined level of contraction (Video 9).

Thereafter, the SAT is disconnected from the implant and the CDS is removed. Finally, percutaneous closure of the venous access is obtained (Video 10).