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- ↵*Reprint requests and correspondence:
Dr. Thomas Wisenbaugh, Cardiology Section, Department of Medicine, Tripler Army Medical Center, 1 Jarrett White Road, Tripler AMC, Hawaii 96859-5000, USA.
The American College of Cardiology/American Heart Association (ACC/AHA) guidelines (1)concerning surgery for non-ischemic, severe mitral regurgitation (MR) are complex in that they address 11 distinct clinical categories of patients. Among those categories of patients for whom there is still conflicting evidence or divergence of opinion about the benefit of surgery (class II indications) are those without symptoms who have either mildly depressed ejection fractions (0.50 to 0.60) or have a normal ejection fraction but an end-systolic diameter of 45 to 55 mm (ACC/AHA category 7, class IIa). Another important category for whom there remains some controversy is the asymptomatic patient with preserved left ventricular (LV) function in whom mitral valve repair is highly likely(category 9, class IIb). Waiting too long to perform surgery, particularly when repair is not feasible or fails such that replacement is required, has too often in the past resulted in a very dismal outcome. Any remaining uncertainty about the need for corrective surgery in theses two groups, particularly those in the category with end-systolic diameters of 45 to 55 mm, a size considered by some to be dangerous, needs to be resolved.
What would be required to move either of these two categories from class IIa and IIb, respectively, to a class I indication (treatment is useful)? The difficulty in sending asymptomatic patients to surgery is that the operation cannot make them feel better (assuming they were truly asymptomatic before surgery, an assumption that patients may later find was incorrect). For asymptomatic patients with preserved LV function amenable to repair(ACC/AHA category 9) for whom the long-term natural history may be good (except for those with flail valves), the question can be restated: “What are the chances for successful repair with survivorship and avoidance of a prosthesis?” Let us examine some recent, relevant, published results of mitral repair (Table 1) (2–5).
In the series reported Braunberger et al. (2), the post-repair survival rate was said to be similar to the survival rate for a normal population with the same age (56 ± 10 years, 48% 20-year survival). Others have reported normal life span after mitral repair. In two of the studies cited in Table 1, re-operation rates were similar to those patients undergoing valve replacement as their initial procedure, which testifies to the durability of repair for non-rheumatic regurgitation in experienced hands. With early mortality rates of 1.4% to 2.9%, a risk of needing early re-operation and mitral valve replacement (MVR) of about 1% to 2%, and long-term survival that approximates that of the general population, we are approaching a class I indication to recommend mitral surgery to patients with very severe MR who appear amenable to repair even if they are asymptomatic and have preserved LV function. A compelling case has certainly been made for this approach when the etiology involves a flail leaflet (6), though this was not known at the time the guidelines (1)were published in 1998. Even when severe MR is not due to such extreme pathology, the reassurance provided by the current article of Matsumura et al. (5)in this issue of the Journal, that the LV dimensions you see before will be even better—and not unexpectedly and dismally worse—after repair, should make us lean more to early surgery if we have access to a center of excellence.
The current article by Matsumura et al. (5)also carries a message with regard to the category of asymptomatic patient with an LV end-systolic diameter between 45 and 55 mm whose MR may or may not be amenable to repair (ACC/AHA category 7). This has clearly been a dangerous category in previous, smaller studies of MVR, even in the era of chordal preservation. A previously suggested cut point has been confirmed in the current study of mitral valve preservation: when end-systolic diameter increased from 35 to 40 mm to 40 to 45 mm, the risk of having a postoperative ejection fraction of <50% increased from 5% to 22%. For an end-systolic diameter >45 mm, the risk increased to 30%. These risks are greater if valve replacement is performed and the valve apparatus cannot be preserved. Thus, an end-systolic diameter >40 mm is clearly a danger zone, and in my opinion, asymptomatic patients with MR should be operated with a mitral-sparing operation, if at all possible, when they enter it (class I indication).
The article under discussion also has an impact on ACC/AHA categories not targeted above: patients in ACC/AHA category 4 are symptomatic or asymptomatic patients with moderate LV dysfunction, ejection fraction 0.30 to 0.50, and/or end-systolic dimension 50 to 55 mm. Though most of us would agree that these patients should not be denied surgery on the basis of LV dysfunction alone, the results of valve replacement are so poor with this degree of end-systolic enlargement that I do not tell my frail and elderly patients who are in this category that they have a class I indication for valve replacement. However, if their valves were amenable to repair, and I knew I could get them to surgeons like Matsumura et al. (5), I might do so: a number of their patients with this degree of end-systolic enlargement before surgery had normal LV function after repair.
Other virtues of the current study include the following: 1) the study of a pure population with a degenerative etiology; 2) the absence of coronary artery disease and the need for coronary artery bypass graft, which negatively impacts the results of mitral surgery; 3) the use of complex, modern surgical techniques, including expanded polytetrafluoroethylene sutures for anterior leaflet chordae; and 4) echo follow-up with data including the LV parameters. These echo findings were of particular interest to me. A long-held notion is that correction of MR “afterloads” the LV and thus causes ejection fraction to fall. The current study convincingly shows that both the end-diastolic and -systolic diameters decrease after repair of MR, which implies the ventricle has actually been “unloaded” and not “afterloaded.” What doesafterload the LV is disruption of chordal integrity by radical mitral valvectomy. This is responsible for most cases of unexpected, dismal outcome after mitral valve surgery. And there is just no excuse for it anymore.
☆ The views expressed in this abstract/manuscript are those of the author and do not reflect the official policy or position of the Department of the Army, Department of Defense, or the U.S. Government.
↵* Editorials published in the Journal of the American College of Cardiologyreflect the views of the authors and do not necessarily represent the views of JACCor the American College of Cardiology.
- American College of Cardiology Foundation
- Bonow R.O.,
- Carabello B.,
- de Leon A.C. Jr..,
- et al.
- ↵Matsumura T, Ohtaki E, Tanaka K, et al. Echocardiographic prediction of left ventricular dysfunction after mitral valve repair for mitral regurgitation as an indicator to decide optimal timing of repair. J Am Coll Cardiol 2003;42:458–63
- Grigioni F.,
- Enriquez-Sarano M.,
- Ling L.H.,
- et al.