Correspondence

Mitral-Valve Prolapse

N Engl J Med 1999; 341:1471-1472November 4, 1999

Article

To the Editor:

The article by Freed et al. (July 1 issue)1 is a major contribution to the study of the prevalence of mitral-valve prolapse and the various symptoms that have been attributed to it. Unfortunately, their findings do not justify the enthusiasm that this article has generated in the media with respect to the low prevalence of mitral-valve prolapse and its benign outcome.

The authors deserve credit for demonstrating that chest pain and dyspnea are not more common in subjects with mitral-valve prolapse than in subjects without prolapse and that the previously reported association was probably due to a selection bias. However, in the absence of Holter monitoring, they cannot claim that there was an “absence of a significant difference in the prevalence of ventricular ectopy between those with prolapse and those without prolapse.”

Their finding of a substantially lower prevalence of mitral-valve prolapse than previously reported has been widely disseminated. In fact, a 5 percent prevalence has been reported in previous reviews,2 as compared with the 2.4 percent prevalence reported by the authors, on the basis of strict echocardiographic criteria. I submit that a valvular disorder that affects 2.4 percent of the population is still the most common cardiac valvular abnormality in industrialized countries, a finding that the authors have attempted to minimize in their article and interviews with the media.

The authors cannot claim to report on the clinical outcome of this valvular abnormality on the basis of a study of 84 patients who had mitral-valve prolapse without long-term follow-up after the diagnosis. Indeed, most of the complications of mitral-valve prolapse — including mitral regurgitation, with or without ruptured chordae tendineae and endocarditis — occur in old age. Despite the generally benign outlook stressed by the authors, mitral-valve prolapse, which affects 2.4 percent of the population, accounts for most cases of severe mitral regurgitation3 including 90 percent of the cases of ruptured chordae tendineae.4 Moreover, among adults with native-valve endocarditis, it is the most commonly recognized lesion.5

Robert M. Jeresaty, M.D.
Saint Francis Hospital and Medical Center, Hartford, CT 06105-1299

5 References

1. 1

   Freed LA, Levy D, Levine RA, et al. Prevalence and clinical outcome of mitral-valve prolapse. N Engl J Med 1999;341:1-7
   Full Text | Web of Science | Medline

2. 2

   Jeresaty RM. Mitral valve prolapse: an update. JAMA 1985;254:793-795
   CrossRef | Web of Science | Medline

3. 3

   Waller BF, Morrow AG, Maron BJ, et al. Etiology of clinically isolated, severe, chronic, pure mitral regurgitation: analysis of 97 patients over 30 years of age having mitral valve replacement. Am Heart J 1982;104:276-288
   CrossRef | Web of Science | Medline

4. 4

   Jeresaty RM, Edwards JE, Chawla SK. Mitral valve prolapse and ruptured chordae tendineae. Am J Cardiol 1985;55:138-142
   CrossRef | Web of Science | Medline

5. 5

   McKinsey DS, Ratts TE, Bisno AL. Underlying cardiac lesions in adults with infective endocarditis: the changing spectrum. Am J Med 1987;82:681-688
   CrossRef | Web of Science | Medline

To the Editor:

Thirty-six years after the original report by Barlow et al.,1 mitral-valve prolapse remains a diagnosis of considerable interest and some controversy, as evidenced by the article by Freed et al. and the accompanying editorial.2 Although the prevalence of mitral-valve prolapse throughout the world might have been overestimated as a result of the use of nonuniform echocardiographic criteria, as pointed out by Nishimura and McGoon,2 it is undeniably the most common cause of mitral regurgitation.3 This point has been well documented in patients who were assessed on the basis not only of echocardiography and cardiac catheterization but also of surgical findings and pathological examination of the excised valves at the time of valve replacement.3

Therefore, although mitral-valve prolapse may not be as serious a disease as was previously thought, one of its most serious complications — namely, mitral regurgitation — remains a major issue in the care of affected patients.4 Fortunately, mitral-valve repair, rather than replacement, is now possible in nearly 90 percent of patients with mitral-valve prolapse, with an operative mortality rate of approximately 2 percent and an excellent long-term outcome.5

Tsung O. Cheng, M.D.
George Washington University, Washington, DC 20037

5 References

1. 1

   Barlow JB, Pocock WA, Marchand P, Denny M. The significance of late systolic murmurs. Am Heart J 1963;66:443-452
   CrossRef | Web of Science

2. 2

   Nishimura RA, McGoon MD. Perspectives on mitral-valve prolapse. N Engl J Med 1999;341:48-50
   Full Text | Web of Science | Medline

3. 3

   Cheng TO. Mitral valve prolapse: an overview. J Cardiol Suppl 1989;21:3-20
   Medline

4. 4

   Cheng TO. Mitral valve prolapse. Dis Mon 1987;33:481-534
   CrossRef | Web of Science | Medline

5. 5

   Spencer FC, Galloway AC, Grossi EA, et al. Recent developments and evolving techniques of mitral valve reconstruction. Ann Thorac Surg 1998;65:307-313
   CrossRef | Web of Science | Medline

Author/Editor Response

The authors reply:

To the Editor: Dr. Jeresaty states that previous articles have reported a 5 percent prevalence of mitral-valve prolapse and that our finding of a lower prevalence was overemphasized. To our knowledge, our finding of a 2.4 percent prevalence among subjects in the Framingham Heart Study is the lowest one identified in a community-based study of mitral-valve prolapse. We believe that the difference between the two rates is noteworthy, since it represents millions of people in the U.S. population. Moreover, prevalence rates of 10 to 15 percent or more have been reported and are more consistent with the findings in routine clinical experience with the use of less specific criteria for mitral-valve prolapse.

In response to both Dr. Jeresaty's and Dr. Cheng's comments that mitral-valve prolapse is the most common cause of severe mitral regurgitation in the population, we submit that this assertion applies to surgical referral series and does not directly pertain to the findings in our study. We asked the following question: What percentage of the people with mitral-valve prolapse in the community have mitral regurgitation at a certain point in time (i.e., at the fifth examination of the offspring cohort of the Framingham Heart Study)? To this end, we accurately stated that moderate and severe mitral regurgitation are relatively uncommon in people with mitral-valve prolapse in the community. In addition, we examined the Framingham data base of 3351 subjects who participated in the fifth examination of the offspring cohort to address the issue of whether mitral-valve prolapse is the commonest cause of clinically significant mitral regurgitation. We found that mitral-valve prolapse was present in only 26.9 percent of subjects with moderate or severe mitral regurgitation (Figure 1Figure 1Prevalence of Mitral-Valve Prolapse According to the Qualitative Severity of Mitral Regurgitation.).

We agree with Dr. Jeresaty that our investigation did not include long-term monitoring for complications. In our article, we underscored the point that this was a cross-sectional study and therefore could not provide longitudinal data on outcome. However, in our subjects, given the low prevalence of conditions previously linked to mitral-valve prolapse, including atrial fibrillation, congestive heart failure, syncope, and cerebrovascular disease, one may infer that the course is more benign than previously believed. In addition, our subjects, whose mean age was 55 to 57 years, should have included persons with mitral-valve prolapse in whom complications had ample opportunity to develop.

We maintain that previous hospital-based series, which also were not longitudinal, overstated the severity of complications attributable to mitral-valve prolapse because of referral bias. We assert that mitral-valve prolapse is similar to hypertrophic cardiomyopathy in that when it was examined in the community, what was once thought to be a grave disease was discovered to be far more benign.1,2

Lisa A. Freed, M.D.
Daniel Levy, M.D.
Framingham Heart Study, Framingham, MA 01702-6334

Robert A. Levine, M.D.
Massachusetts General Hospital, Boston, MA 02114

Jane C. Evans, D.Sc., M.P.H.
Emelia J. Benjamin, M.D.
Framingham Heart Study, Framingham, MA 01702-6334

2 References

1. 1

   Spirito P, Chiarella F, Carratino L, Berisso MZ, Bellotti P, Vecchio C. Clinical course and prognosis of hypertrophic cardiomyopathy in an outpatient population. N Engl J Med 1989;320:749-755
   Full Text | Web of Science | Medline

2. 2

   Maron BJ, Casey SA, Poliac LC, Gohman TE, Almquist AK, Aeppli DM. Clinical course of hypertrophic cardiomyopathy in a regional United States cohort. JAMA 1999;281:650-655[Erratum, JAMA 1999;281:2288.]
   CrossRef | Web of Science | Medline

Citing Articles (2)

Citing Articles

1. 1

   Tsung O. Cheng, Xin-Fang Wang, Jing Zhang, Ming-Xing Xie. (2010) Recent advances in the echocardiographic diagnosis of mitral valve prolapse. International Journal of Cardiology 140:1, 1-11
   CrossRef

2. 2

   Tsung O. Cheng. (2000) Combined mitral valve repair and the cox maze procedure for mitral valve prolapse and regurgitation and associated atrial fibrillation. The Journal of Thoracic and Cardiovascular Surgery 119:3, 634
   CrossRef