Benefits of Evolution to a Simpler Mitral Valve Repair Technique
Cardiac surgeons at the University of Maryland Medical Center (UMMC) have performed a retrospective study of their large MV repair experience to assess the impact of a progressive change from resectional to cordal-replacement techniques.
The study stratified patients into two eras: between January 2004 and June 2011 (Era-1, n=405), when 62% of MV cases were performed with resectional techniques and 38% utilized an artificial cordal approach, and between July 2011 and September 2017 (Era-2, n=438), when nearly all (98%) cases were done using artificial ePTFE (Gore-Tex) cords.
The primary outcome studied was repair failure, as measured by greater than moderate mitral valve regurgitation (MR) or MV reoperation, and secondary outcomes included stroke and cumulative survival. The study concluded that both traditional, patient-tailored resectional repair and the simpler, cordal repair yielded the same excellent patient outcomes. +/- on this: Data analysis revealed that the only significant risk factor for repair failure in either case was having higher systolic pulmonary artery pressure prior to surgery.
Emergence of Cordal MV Repair
Over the years, use of expanded polytetrafluoroethylene (ePTFE, Gore-Tex) cords to replace the elongated or ruptured chordae tendinae in a diseased MV before the insertion of an annuloplasty ring has emerged as an alternative to traditional repairs that reshape leaflets through resection and reconstruction. These ePTFE cords are sutured in a looped pair, spaced 3-4 mm apart on the prolapsed segments' edges, and adjusted in length as necessary to create coaptation without stenosis. Mid-term and long-term outcomes of cordal MV repair have been documented in the literature as excellent, and these repairs are estimated to have a 25-year durability.
Cardiac surgeons at UMMC initially used artificial cordal repair as an adjunct to resectional MV repair in cases with anterior leaflet prolapse. As they gained experience with cordal repair, however, it became evident that it was the ideal approach for nearly all patients with degenerative MR.
A Simpler MV Repair Approach
Cordal MV repairs are much simpler procedures than traditional resectional MV repairs in large part because they do not require the high level of patient-tailoring difficult to offer consistently to all patients. MV repair with prolapsing leaflet resection and insertion of an annuloplasty device often requires adjunct techniques, which may include sliding plasty, annular plication, chordal transfer, anterior leaflet resection, commissuroplasty and/or other additional surgical maneuvers. Moreover, the decisions made during a resectional procedure – such as the type of resection and amount of tissue removed – are irrevocable, whereas in repair with ePTFE cords, coaptation can be tested intraoperatively and the procedure reversed if necessary. Finally, because of the high degree of patient-tailoring required by resectional MV repairs, they are difficult to teach to surgeons-in-training.
Because of the challenges associated with resectional repair, in July 2011, the cardiothoracic surgeons at UMMC all but abandoned the approach for MV repair.
Added Benefits of Cordal MV Repair
The near-universal use of ePTFE cordal repair at UMMC has reduced intraoperative decision-making because repairs are systematically similar regardless of patient: (1) determine leaflet prolapse location, (2) resuspend the prolapsed leaflets with cords, (3) measure the anterior MV leaflet and insert an annuloplasty ring of corresponding size and (4) test coaptation with saline and adjust ePTFE cord length as necessary. In large part because this procedural system can be applied for all patients with degenerative MV disease, myocardial ischemia and cardiopulmonary bypass (CPB) times were 9 and 12 minutes shorter respectively in Era-2 compared to the earlier era.
Concerns About SAM Incidence Associated with Cordal Repair
The cardiac surgery team at UMMC was initially concerned that because cordal MV repair does not address excess leaflet tissue, the approach might result in higher incidence of systolic anterior motion (SAM). However, the surgeons found similar rates of early and late SAM with both approaches to repair. Moreover, SAM is in large part preventable through exactingly positioning leaflets and using the appropriate annuloplasty ring size. In the rare case SAM occurs, UMMC cardiac surgeons correct it by going back on bypass to shorten the cords suspending the posterior leaflet and, if needed, adding a curtain stitch to the anterolateral commissure.
Cordal MV Repair Easier to Teach to Trainees
The high level of patient customization that resectional MV repair requires makes it a difficult procedure for all but experienced cardiac surgeons and therefore it is challenging to teach others. Because cordal repair techniques are universal regardless of degenerative MV disease pathology, trainees can more readily learn the systematic approach to MV repair and feel confident in surgical treatment for a wide variety of MR cases.
Outstanding Outcomes with Mitral Valve Repair for Degenerative Disease at the University of Maryland
The UMMC team was able to repair 99.5 percent of degenerative valves, which compares favorably to the 80% rate nationwide1. Benefits of repair compared to replacement include lower operative mortality, reduced long-term risks of valve infection and stroke, and avoidance of anticoagulation for mechanical valves and reoperation for failed tissue replacement valves. Overall the operative mortality in the UMMC mitral valve series was 0.5%.
Learn more about UMMC's Mitral Valve updates.
Comparison Between the Era-1 and Era-2 Study Cohorts
| ERA-1 1/04 - 6/11; n=403 |
ERA-2 7/11 - 9/17; n=438 |
|
|---|---|---|
| Median Patient Age (P<0.001) |
59±13 | 62±12 |
| Resectional/Cordal Repair (P<0.001) |
62% / 38% | 98% / 2% |
| Annuloplasty Ring: Partial Flexible/ Complete Non-Planar Semi-Rigid (<0.000) |
51% / 47% | 0% / 99% |
| Median CPB Time (P<0.001) |
109 min. | 97 min. |
| Median Myocardial Ischemia Time (P<0.001) |
88 min. | 79 min. |
| InteroperativeSAM Requiring Intervention (P=0.488) |
3% | 4% |
| Operative Mortality (P<0.999) |
0.5% | 0.5% |
| Inhospital Postoperative CVA (P>0.999) |
0.5% | 0.7% |
| Freedom from Repair Failure at 5 Years (P=0.707) |
95.1% | 95.5% |
| Freedom from Stroke (P=0.538) |
96.8% | 95.3% |
| Overall 5 year survival (P=0.006) |
89.4% | 94.2% |
For more information about treatments for mitral valve disease at the University of Maryland Medical Center, call 410-328-5842.
1Pasrija C, Tran D, Ghoreishi M, Kotloff E, Yim D, Finkel J, Holmes SD, Na D, Devlin S, Koenigsberg F, Dawood M, Quinn R, Griffith BP, Gammie JS. Degenerative mitral valve repair simplified: an evolution to universal artificial cordal repair. Ann Thorac Surg. 2019 Dec 18. pii: S0003 4975(19)31884 3. doi: 10.1016/j.athoracsur.2019.10.068.