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J Am Coll Cardiol, 2005; 46:2134-2140, doi:10.1016/j.jacc.2005.07.065
(Published online 18 October 2005). © 2005 by the American College of Cardiology Foundation |







* Evanston Hospital, Evanston Illinois
Columbia University, New York, New York
University of Pennsylvania, Philadelphia, Pennsylvania
Swedish Medical Center, Seattle, Washington
|| Emory University, Atlanta, Georgia
¶ The Cleveland Clinic, Cleveland, Ohio
# Cardiovascular Institute, Mt. View, California
** Hospital Miguel Perez-Carrefio, Centro Medico Caracas, Caracas, Venezuela

University of California, San Francisco, California
Manuscript received June 3, 2005; revised manuscript received July 12, 2005, accepted July 19, 2005.
* Reprint requests and correspondence: Dr. Ted Feldman, Evanston Hospital, Cardiology Division-Burch 300, 2650 Ridge Avenue, Evanston, Illinois 60201. (Email: tfeldman{at}enh.org).
| Abstract |
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BACKGROUND: A surgical technique approximating the middle scallops of the mitral leaflets to create a double orifice with improved leaflet coaptation was introduced in the early 1990s. Recently, a percutaneous method to create the same type of repair was developed. A trans-septal approach was used to deliver a clip device that grasps the mitral leaflet edges to create the double orifice.
METHODS: General anesthesia, fluoroscopy, and echocardiographic guidance are used. A 24-F guide is positioned in the left atrium. The clip is centered over the mitral orifice, passed into the left ventricle, and pulled back to grasp the mitral leaflets. After verification that MR is reduced, the clip is released.
RESULTS: Twenty-seven patients had six-month follow-up. Clips were implanted in 24 patients. There were no procedural complications and four 30-day major adverse events: partial clip detachment in three patients, who underwent elective valve surgery, and one patient with post-procedure stroke that resolved at one month. Three additional patients had surgery for unresolved MR, leaving 18 patients free from surgery. In 13 of 14 patients with reduction of MR to
2+ after one month, the reduction was maintained at six months.
CONCLUSIONS: Percutaneous edge-to-edge mitral valve repair can be performed safely and a reduction in MR can be achieved in a significant proportion of patients to six months. Patients who required subsequent surgery had elective mitral valve repair or intended replacement.
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| Methods |
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A clip delivery system, with a clip attached to its distal end, is passed through the guide catheter. This system is steerable using a two-knob coaxial system that permits medial-lateral and anterior-posterior steering. The clip delivery system is advanced through the guide catheter into the left atrium and is positioned so that the clip is orthogonal to the three planes of the mitral valve and over the origin of the regurgitant jet.
The clip is a polyester-covered mechanical device with two arms that are opened and closed by control mechanisms on the clip delivery system (Fig. 1). The two arms have an opened span of approximately 2 cm when opened in the grasping position. The width of the clip is 4 mm. On the inner portion of the clip is a U-shaped "gripper" that matches up to each arm and helps to stabilize the leaflets from the atrial aspect as they are captured during closure of the clip arms (Fig. 2). Leaflet tissue is secured between the closed arms and each side of the gripper, and the clip is then closed and locked to effect and maintain coaptation of the two leaflets.
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Patient selection. Patients were selected for therapy if they met basic criteria for intervention from the American College of Cardiology/American Heart Association Joint Task Force recommendations regarding therapy for valvular heart disease (9). Patients with moderate-to-severe or severe MR who were symptomatic or asymptomatic patients with moderate-to-severe or severe MR with compromised left ventricular function (left ventricular ejection fraction <60% or left ventricular end-systolic dimension >45 mm) were selected (Table 1). A screening echocardiogram was reviewed by a core laboratory (University of California at San Francisco). Mitral regurgitation was graded according to the criteria of the American Society of Echocardiography (10). On the basis of the screening echocardiogram, a minimum of three of six criteria for moderate to severe (3+) or severe (4+) MR were required for entry; at least one of the three had to be quantitative (Table 1). The inclusion criteria included flail segment width <1.5 cm and a regurgitant jet origin from within the central two-thirds of the line of leaflet coaptation. Specific anatomic measurements were made according to the protocol.
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Study end points.
The primary end point of the study was acute safety at 30 days defined as freedom from death, myocardial infarction, cardiac tamponade, cardiac surgery for failed clip, clip detachment, stroke, or septicemia. The end point was met if the major adverse event (MAE) rate was
34.4%, which was based on the event rate in the Society of Thoracic Surgeons cardiac surgical database of 17.0% for mitral valve surgery, with a large margin of error for a relatively small sample size (11).
Secondary safety end points included in-hospital major vascular complications, 30-day and 6-month major bleeding, endocarditis, clip thrombosis, hemolysis, and mitral valve injury. At the six-month time point, cardiac surgery for a failed clip or device was also a secondary safety end point.
Echocardiograms were performed according to a pre-specified protocol at baseline, pre-discharge, and at one and six months (Fig. 3). The efficacy goal was defined as MR severity of
2+ after clip placement. On the baseline and follow-up (pre-discharge, 30-day, 6-month) echocardiograms, MR was graded based on four of the six criteria used at screening. The vena contracta width and the regurgitant orifice area have not been validated for the double-orifice valve, and thus were eliminated from this analysis. A four-point score was based on the average of four variables graded on a scale of 1 to 4. An overall "expert" grade was also assigned based on integrated core laboratory analysis that considered regurgitant volume, regurgitant fraction, color jet penetration, pulmonary venous flow pattern, and continuous-wave Doppler characteristics of the regurgitant jet, pulmonary artery pressure, and left atrial size using a previously validated approach (12). To evaluate for the potential development of mitral valve stenosis, mitral valve area was measured by planimetry, pressure half-time, and mean gradient. After the procedure, each of the two orifices underwent planimetry at the level of the clip and was summed for the mitral valve area.
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| Results |
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Nine procedures were done at one site, eight procedures at one site, three at two sites, and two each at two sites. The average device time defined as the time from guide insertion until clip delivery system removal diminished with experience. For all 27 procedures, the mean device time was 204 ± 116 min. First procedures (six patients) had a mean device time of 227 min, second procedures (six patients) had a mean device time of 363 min (one of these was the first time two clips were placed, with a procedure time of 530 min), and third procedures (four patients) had mean device time of 196 min. For procedures in which one clip was placed, the mean device time was 168 ± 73 min. Two clip cases had a mean device time of 396 ± 145 min. Cases in which no clip was ultimately implanted had a mean device time of 198 ± 19 min. Because clip placement was guided primarily by echocardiography, fluoroscopy was not used continuously during the procedure.
In-hospital outcomes are shown in Table 4. The length-of-stay time includes three patients who went on to have surgery during the initial hospitalization.
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2+, and 13 of 14 maintained this improvement at six months. The mitral valve area by planimetry was 6.4 ± 1.6 cm (2) at baseline and 3.4 ± 1.7 cm (2) at six months, and by pressure half-time was 4.4 ± 0.80 cm (2) at baseline and 2.9 ± 0.83 cm (2) after six months.
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Among patients having six-month follow-up transthoracic echocardiograms, color Doppler evidence of atrial septal shunting was present in four, absent in seven, and indeterminate in eight patients.
Among patients discharged from the hospital with a clip in place, the overall freedom from valve surgery at six months was 18 of 22 (82%).
| Discussion |
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The clip is deliverable using the trans-septal approach. Coaptation of the anterior and posterior leaflets produces a double-orifice mitral valve and can reduce MR. Combined fluoroscopic and echocardiographic guidance is adequate to orient the device properly in multiple planes so that it can be positioned over the center of the mitral valve orifice and the origin of the MR jet. An echo short-axis view, either transthoracic or transesophageal, is needed to orient the clip perpendicular to the line of leaflet coaptation before grasping. The grasping and capturing mechanisms of the clip were both used successfully. It is possible to grasp and safely release mitral leaflets repeatedly and to reposition the device to achieve optimal control of MR. The gripping mechanism results in stability of the clip on the mitral leaflets both before and after detachment in most patients. It has been established that a tissue bridge forms across the clip in animal models (7). This healing response reproduces the existing surgical approach and has not resulted in significant inflow obstruction in any patient. The surgical approach for edge-to-edge repair has been in use for over a decade, with excellent results in many patients.
Reductions in MR were achieved in most of our patients. In some, the acute result was almost complete resolution of regurgitation, whereas in others it has resulted in a significant improvement in MR: 64% of patients discharged with a clip had MR
2+ after one month, which increased to 82% when each investigators first and second procedures were excluded. Although the sample size is small, this finding may support the presence of a learning curve. Importantly, 93% of patients with MR
2+ at one month had a stable result after six months.
The mean device time from guide catheter insertion until clip delivery system withdrawal ranged from over 200 min for first procedures to a minimum of 70 min in a ninth procedure. One case that involved placement of two clips lasted over 500 min. Despite the duration of the procedures, manipulation of this relatively large system of catheters in the left atrium, mitral orifice, and left ventricle was tolerated remarkably well. Patients were hemodynamically stable throughout the procedure in all cases. No patient required inotropic support for completion of the procedure, and none developed atrial fibrillation, ventricular tachycardia, or acute or delayed pericardial tamponade. The hemodynamic stability observed during this procedure is in marked contrast to the instability of patients undergoing other percutaneous catheter valve procedures such as balloon aortic and balloon mitral valvuloplasty or percutaneous aortic valve replacement. The hemodynamic stability of these patients allows the interventional team to remain focused on steering the clip to the optimal location over the mitral orifice, grasping the leaflets, and ensuring a good result rather than being preoccupied with the management of an unstable patient.
The ability to grasp and remove the clip both during the initial procedure and also during subsequent surgery is an important aspect of the technology. In three patients, multiple grasps were made without adequate control of MR and the device was removed. This did not preclude conventional valve surgical therapy including valve repair in any of these patients. The reversibility of the grasping mechanism of the clip is also critically important. It has been possible to grasp leaflets and assess the degree of improvement in MR, and then reposition the clip if necessary to optimize control of MR. The clip has also been removed during subsequent open surgical procedures. Six patients with MR after percutaneous repair have undergone re-intervention with a time interval between clip deployment and surgery from 1 to 133 days (13). During surgery, the clips were uneventfully removed in all five cases in which the intention was to repair the valve with no limitation in surgical options, including one patient treated with two clips.
Safety. The safety of the device has been clearly shown. The large caliber of the trans-septal puncture has not caused any specific problems. Trans-septal access using devices of this size has been accomplished previously without long-term sequelae with double-balloon mitral valvuloplasty, and more recently with trans-septally delivered percutaneous bypass procedures.
The 24-F femoral venous puncture has been manageable in all of these patients without any special techniques. Manual compression or pneumatic compression using the FemoStop device has been used without any late bleeding. Atrial septal shunting from the trans-septal puncture has not been clinically important in any patients. Most seem to be healed by six months.
Partial clip detachment from one leaflet without embolization occurred in three patients. One of these was detected at the 24-h post-procedure echocardiogram, and the other two were noted at the planned protocol-driven one-month echocardiographic examination. None of these patients had a change in symptoms or a clinical event related to clip detachment from one leaflet. Careful retrospective review of the intraprocedural echocardiograms in these three patients suggests that the angle between the open clip arms and the long axis of the line of mitral coaptation was not perpendicular at the time the leaflets were grasped. Depending on the extent of misalignment, this may result in less leaflet capture on one or both sides of the two clip arms. Based on this experience, it is apparent that careful assessment to confirm a perpendicular orientation of the open clip arms to the long axis of the mitral leaflet line of coaptation is a critical step before grasping the leaflets and closing the clip. In addition, proper leaflet insertion into the closed clip arms should be systematically assessed before final clip deployment.
Study limitations.
The major limitation of this technique has been the inability to completely obliterate MR in all patients. This article characterizes early experience with a first-in-class device therapy for MR. As seen in Figure 3, 14 of 27 patients had MR reduced to
2+ at six months. In four patients, the use of two clips was needed to achieve an adequate reduction in MR. It is clear that the geometry of the regurgitant orifice and the origin of the MR jet are highly variable in position and dimension. The need to increase the width of the apposed segments of coaptation with two-clip devices can be assessed after a single clip has been placed, if the residual jet origin can be clearly seen adjacent to the deployed clip. Similar to surgical edge-to-edge repair, it is possible that creation of a triple-orifice valve will be effective in some patients as well (14). The experience with functional MR in this trial is limited, although initially positive. Additional experience will be required to determine an optimal strategy for the use of multiple clips. The potential to create mitral stenosis must also carefully be evaluated as multiple clips are used. It is notable that mitral stenosis was not created in any of these patients, including the four who received two clips. Experience is limited to 25 patients with degenerative MR and 14 patients with flail leaflets, so the specific features of this etiology that may limit the utility of this first-generation device will also require further experience to define. The experience with functional MR in this trial is limited, although initially positive. The primary reason that experience with functional patients is limited is the protocol mandated exclusion of patients with previous mediastinal surgery. Longer-term follow-up will be required to determine clinical value in different patient populations.
The surgical approach to MR may involve a combination of edge-to-edge repair and annuloplasty. Satisfactory four-year freedom from reoperation rates have been described among patients having edge-to-edge repair without annuloplasty, as well as in patients in whom edge-to-edge repair was used to supplement annuloplasty (15). Some cases of MR will require more than isolated edge-to-edge repair for adequate therapy. This strategy may be modified in patients who are poor candidates for surgery, in whom no mechanical alternatives for mitral repair are available, and the use of a clip repair without annuloplasty may be the patients only reasonable alternative.
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| Appendix |
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| Footnotes |
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| References |
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