DOI: 10.1111/j.1540-8175.2009.01143.x
CME
C 2010, Wiley Periodicals, Inc.
REVIEW ARTICLE
Parachute Mitral Valve in Adults—A Systematic Overview Fayaz A. Hakim, M.D.,∗ Christopher B. Kendall, R.D.C.S.,† Mohsen Alharthi, M.D.,† Joel C. Mancina, R.D.C.S., R.V.T.,† Jamil A. Tajik, M.D., F.A.S.E., F.A.C.C.,† and Farouk Mookadam, M.Sc., F.R.C.P.C., F.A.C.C.† ∗ Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA; and †Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona, USA
Parachute mitral valve (PMV) is a rare congenital anomaly of the mitral valve apparatus seen in infants and young children. In most instances PMV is associated with other congenital anomalies of the heart, in particular obstructive lesions of the mitral inflow (mitral valve ring) and left ventricular outflow tract (subaortic stenosis), and coarctation of aorta and is referred to as Shone’s complex or Shone’s anomaly. PMV may also occur as an isolated lesion or in association with other congenital cardiac anomalies. Not much is known about PMV in adults as an isolated anomaly or in association with other congenital cardiac anomalies. We reviewed the literature to identify cases of PMV (isolated or associated with other lesions) in adults, to address prevalence, clinical presentation, diagnosis, treatment, and outcome of such patients. (Echocardiography 2010;27:581-586) Key words: parachute, isolated, mitral valve, outcomes, adults True parachute mitral valve (PMV) is characterized by a unifocal attachment of the mitral chordae tendinae resulting in mitral inflow obstruction.1,2 This developmental anomaly is most often associated with other obstructive lesions on the left side of heart (supravalvular mitral ring, subaortic stenosis, and coarctation of aorta) and is known as Shone’s complex or Shone’s anomaly.3 Shone’s complex has been almost exclusively reported in infants and children and the outcome is generally poor, due to the presence of multiple hemodynamically significant lesions requiring several complex surgical interventions with a high mortality.4,5 The outcome of patients with isolated PMV depends upon the severity of the mitral inflow obstruction resulting from this cardiac anomaly. Pathophysiology: A normal mitral valve has two leaflets (a larger anterior leaflet and a smaller posterior leaflet), and chordae tendinae diverge to get inserted into two papillary muscles (anterolateral and posteromedial) (Fig. 1A). PMV exists because the chor-
No conflict of interest exists. Address for correspondence and reprint requests: Farouk Mookadam, M.Sc., F.R.C.P.C., F.A.C.C., Mayo Clinic College of Medicine, 13400 E Shea Blvd, Scottsdale, Arizona 85255, USA. Fax: 480 301 8018; E-mail:
[email protected]
dae tendinae from both mitral valves leaflets instead of diverging to insert into two papillary muscles converge on a centrally placed, single papillary muscle (Fig. 1B). This occurs due to disturbed delamination of the anterior and posterior parts of the trabecular ridge (which normally forms anterolateral and posteromedial papillary muscles respectively) between the 5th and 19th week of gestation, thereby forcing these embryonic predecessors of the papillary muscles to condense into a single papillary muscle.2 The chordae tendinae in PMV are often underdeveloped and hence short, thick, and adherent causing decreased mobility of the valve leaflets and reducing the size of mitral orifice. Furthermore, narrowing of the interchordal spaces results in a smaller secondary mitral orifice causing mitral inflow obstruction. Most patients present during infancy with mitral stenosis of variable severity.4 Rarely the chordae tendinae may be long and lax precluding complete coaptation of the leaflet cusps, which may even prolapse into the left atrium resulting in mitral regurgitation (MR). Uncommonly there may be no functional abnormality of the mitral valve apparatus. PMV usually occurs either as a part of Shone’s complex3 or in association with other congenital heart diseases including aortic valve stenosis (32%), atrial septal defects (54%), and hypoplastic left heart (19%).6 Isolated PMV is rare accounting for less than 1% of all cases.6 This systematic overview will focus on PMV in adults as an isolated lesion or in 581
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Figure 1. Photographs, Showing normal mitral valve (A) with chordae tendinea attached to two papillary muscles (ALPM = anterolateral papillary muscle and PMPM = posteromedial papillary muscle) and PMV (B) with single papillary muscle receiving chordae tendinae from both mitral valve leaflets.
association with other congenital lesions, but exclusive of Shone’s complex. Methods: We conducted an electronic database search of Medline and PubMed for English language papers from January 1, 1960 to December 31, 2008 using the search terms: “isolated,” “parachute,” “mitral valve,” “adults,” and “Shone’s complex.” Further search terms incorporating “associated lesions,” “congenital,” and “cardiac anomalies” were used. An independent search was conducted by two qualified librarians using similar search terms. Bibliographies of the retrieved articles were scanned to identify further reported cases. Care was taken to avoid duplication of the cases. We reviewed and analyzed the demographic profile, clinical features, diagnostic modalities, treatment and outcome of adult patients with PMV. All adult patients with PMV occurring either as an isolated lesion or in association with other congenital cardiac lesions were included. Results: Nine cases of adult PMV meeting inclusion criteria were identified in the literature over a 49-year period from January 1960 to December 2008. Table I summarizes demographic data, clinical characteristics, and outcome of each patient. Mean age was 44 ± 17 years (range 22–65), the majority of the patients (77.77%) were males. Among nine adult patients identified with PMV, five (55.5%) had an isolated PMV, and the remainder (44.4%) had an associated congenital cardiac lesions (double orifice mitral valve with bicuspid aortic valve and coarctation of the aorta in one patient, bicuspid aortic valve with an insignificant coarctation of the aorta in one patient, ventricular septal defect (VSD) with supramitral ring 582
in one patient and double orifice, single ventricle, and pulmonary stenosis in one patient. One adult patient with complete Shone’s complex and one patient with incomplete Shone’s anomaly were identified during our search. The patient with complete Shone’s was excluded from the study. Clinical Presentation: Among adult patients with isolated PMV (Patients 1, 2, 3, 7, and 8), one patient (Patient 2)7 presented with sudden death and was found to have subvalvular stenosis of the PMV on autopsy. Three patients (Patient 1,6 Patient 3;8 Patient 7,9 ) presented with progressive dyspnea. Patient 810 was asymptomatic undergoing evaluation for uncontrolled hypertension. Among adult PMV with an associated congenital cardiac lesion (Patients 4, 5, 6 and 9), atrial fibrillation was the presenting feature in two patients: one had an associated congenital double orifice mitral stenosis, bicuspid aortic valve, and status post coarctation repair (Patient 4)11 ; the second (Patient 5)12 with mild obstructive lesions in both mitral and aortic valves (bicuspid aortic valve) and insignificant coarctation of aorta. One patient (Patient 9),13 with double orifice, single ventricle, and pulmonary stenosis presented with progressive shortness of breath due to congestive heart failure and one patient with a subaortic VSD (Patient 6),14 presented with an asymptomatic holo-systolic murmur. Diagnosis: Seven (78%) of the nine patients were diagnosed by echocardiography. Six patients had both transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). An incremental diagnostic value of TEE has been described in two (Patients 3 and 4).8,11 In
Park et al.13 2007
2007
Patsouras et al.10
41/M
55/M
57/F
28/M
33/M
31/M
65/F
59/M
22/M
sex
Age/
DISV PS
Isolated
Isolated
supravalvular ring
VSD (subaortic)
BAV
CoA (insignificant)
Double orifice MV
CoA (s/p repair) BAV
Isolated
Isolated
Isolated
Congenital HD
other
Isolated or
severe MR,
irregular pulse
mild MS, PS
PMV with
murmur and
TTE, TEE: DISV,
(mild)
with MR
TTE: PMV, MVP
Severe MS
Palpitation
MR, AF and CHF
Hypertension
Uncontrolled
s/p PPM, CHB
TTE, TEE: PMV,
Apical pansystolic
High BP
Home oxygen
PPH; s/p AVR,
confirmed
Echo finding
failure
AF and heart
Medication for
medication
MVR
untouched
PMV
ring
murmur
resection,
Supramitral
Ring
VSD closure,
MVR
MVR CABG
Surgical
(mild)
Hypertension
Coumadin
DC shock
medication
Heart failure
Medical
mid-diastolic
PMV
PMV
Autopsy
VSD,
confirmed
Echo finding
confirmed
Echo finding
muscle
papillary
Single
infarcted
PMV with
Surgery
Treatments
3.9); MR
TTE, TEE: PMV,
LA thrombus
PMV, BAV and
fibrillation VSD (Qp/Qs
MS; TEE:
atrial
TTE: PMV, mild
BAV
TEE: PMV,
severe MS;
orifice MV,
TTE: Double
TEE: PMV
TTE: MR (+3);
Echo
Diagnosis of PMV
murmur,
Holo-systolic
rapid
Paroxysmal
fibrillation
snap
Atrial fibrillation,
atrial
Paroxysmal
CABG
CHF class III s/p
MS
AR and TR
Severe MR Mild
Diagnosis
Clinical
with opening
Diastolic murmur
murmur CHF
Holo-systolic
TR, and AR)
Murmurs (MR,
Findings
Clinical
Worsening SOB
Asymptomatic
Worsening SOB
Asymptomatic
Palpitation
Jaundice
palpitation
Recurrent
CHF
Symptoms of
Sudden death
hemoptysis
Dyspnea
Complaints
Presenting
NA
NA
Asymptomatic
Postop 1 yr F/U:
Asymptomatic
2 yrs F/U:
recovery
Uneventful
Asymptomatic
Postop 1 yr F/U:
Sudden death
Heart failure
Death after 2 yrs
Outcomes
N = case number; TTE = transthoracic echocardiography; TEE = transesophageal echocardiography; HD = heart disease; PMV = parachute mitral valve; MR = mitral regurgitation; MS = mitral stenosis; MVP = mitral valve prolapse; MVR = mitral valve replacement; AR = aortic regurgitation; BAV = bicuspid aortic valve; AVR = aortic valve replacement; VSD = ventricular septal defect; CoA = coarctation of aorta; PPH = primary pulmonary hypertension; PPM = permanent pacemaker; CHB = complete heart block; BP = blood pressure; SOB = shortness of breath; CHF = congestive heart failure; CABG = coronary artery bypass grafting; Postop = post-operative; F/U = follow-up; DISV = double inlet, single ventricle; PS = pulmonary stenosis; NA = not applicable.
9
8
Fitzsimons and
7
Koch9 2005
Abelson14 2001
2001
Prunier et al.12
2000
Yesilbursa et al.11
1995
Shapira et al.8
Edwards7 1973
da Silva and
1971
Glancy et al.6
Year
6
5
4
3
2
1
N
Author
Demographic Characteristics, Clinical Features, Diagnostic Modalities, Treatment and Outcome in Patients with PMV in Adults
TABLE I
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Patient 3, a preoperative TTE failed to diagnose PMV but intraoperative TEE diagnosed a PMV with a single papillary muscle.8 In Patient 4, TTE showed severe mitral stenosis with a double orifice mitral valve, and intraoperative TEE was superior in defining the anatomy of the subvalvular apparatus with a single papillary muscle that supported both mitral valve orifices with a parachute feature.11 In Patient 5, a TTE showed characteristic “parachute” leaflets with a shortened chordae tendinea converging into a single papillary muscle in the parasternal long-axis view, and thickened mitral valve leaflets and thickened and dysplastic chordae tendinea in the apical fourchamber view. TEE further revealed a bicuspid aortic valve and a left atrial thrombus.12 In Patient 6, both TTE and TEE revealed a supramitral ring and a single papillary muscle in fourchamber views.14 In Patient 7, both TTE and TEE were performed, and TEE’s mid-esophageal fourchamber view showed a pear-shaped mitral configuration.9 In Patient 8, only TTE was performed. The parasternal long-axis view showed prolapse of both mitral leaflets with mild MR, while the parasternal short-axis view at the mitral valve level showed an eccentric nonstenotic mitral valve orifice, and at the papillary muscle level a large posteromedial papillary muscle that received all the chordae was seen. An apical long-axis view showed a typical parachute deformity of the mitral valve with a normal opening and common attachment of all the chordae. The chordae were elongated which was atypical—typically the chordae are shortened and thickened.11 Two patients (Patients 1 and 2)6,7 had the diagnosis of PMV made at autopsy. Hemodynamic Consequences of the Adult PMV: Four (44%) patients had mitral subvalvular or valvular stenosis: three had either severe (Patients 2 and 7)7,9 or mild (Patient 5)12 subvalvular stenosis, and one patient (Patient 4)11 had a severe mitral valve stenosis with a congenital double orifice mitral valve. Five (56%) patients had MR: one (Patient 1)6 had severe mitral valve regurgitation with calcium noted on fluoroscopy, one (Patient 9)13 had severe MR associated with mild mitral stenosis, and another (Patient 3)8 with severe mitral valve regurgitation due to infarction of the single papillary muscle. In this patient the PMV was functionally normal until infarction occurred. The remainder had mild MR with (Patient 8)10 or without (Patient 6)14 mitral valve prolapse. Treatments and Prognosis: Mitral valve replacement (MVR) was performed in three (38%) patients: Patient 3 with severe 584
mitral valve regurgitation secondary to ischemic papillary muscle dysfunction underwent MVR combined with coronary artery bypass grafting. At 1-year follow-up she was asymptomatic.8 Patient 4 with significant mitral stenosis in a double orifice underwent MVR with a 31-mm Carbomedics (Austin, TX, USA) prosthesis without complication and no long-term follow up course was mentioned.11 Patient 7 with significant mitral subvalvular stenosis underwent MVR with a Carpentier–Edwards pericardial mitral valve (Edwards Lifesciences, Irvine, CA, USA) and no follow-up course was described.9 Patients without surgical correction of the PMV are described below: One patient (Patient 2) with hemodynamically significant subvalvular stenosis presented with sudden death.7 Patient 1 presented with dyspnea, combined with severe MR and mild aortic regurgitation he was medically managed for 2 years eventually dying of heart failure.6 Patient 5 presented with rapid atrial fibrillation, sinus rhythm was restored by an external electric shock and was asymptomatic during the 2 years follow-up.12 Patient 6 presented with a large subaortic VSD undergoing VSD patch closure, and supramitral ring resection at which time the presence of a PMV was confirmed—it was left untouched. At 1-year follow-up, the patient remained asymptomatic with a small residual VSD and mild MR.14 In Patient 8, the diagnosis of an isolated PMV was made incidentally during investigations for hypertension.10 One patient (Patient 9) with associated double orifice single ventricle and pulmonary stenosis refused surgical interventions and was lost to follow-up.13 Discussion: From the literature search spanning almost five decades it appears that PMV is rarely seen in the adult population. The majority is male (seven out of nine). Isolated PMV was seen in five out of nine of this group. PMV in association with other congenital lesions was seen in four out of nine of patients. Combined bicuspid aortic valve and coarctation of the aorta was seen in two patients.11,12 Compared to pediatric PMV,4 concomitant cardiac abnormalities are uncommon in adult PMV. We speculate that this is because combined complex lesions present early in life and usually requires multiple surgical corrections with high mortality. Adults with PMV represent a smaller group of patients with milder lesions who escape detection until adulthood. Furthermore, the condition may be underdiagnosed in asymptomatic adults who never have the need for echocardiography. Finally adults with PMV even after echocardiography may not have a diagnosis confirmed. The diagnostic criteria for PMV are shown in Table II.
Parachute Mitral Valve in Adults—a Systematic Overview
TABLE II Diagnostic Characteristics of PMV Pathology
Echocardiography
Single papillary muscle Shortened/thickened chordae tendinea converge into a single papillary muscle or one major papillary muscle LV short-axis view At mid-papillary level: single papillary muscle At basal level: Parachute leaflets LV long-axis view Shorten /thickened (typical) or elongated chordae converge into a single papillary muscle Four-chamber view Thickened mitral valve leaflets and thickened and dysplastic chordae tendinea Pear-shaped mitral configuration with a diastolic dome shape
LV = left ventricular.
Adult PMV may have normal hemodynamics (three out of nine) or Doppler evidence of significant stenosis (three out of nine) or regurgitation (three out of nine). Only one adult patient with complete Shone’s complex15 was identified during our search suggesting that in general Shone’s anomaly presents early or are fatal during infancy or childhood. Echocardiography establishes the diagnosis in the majority of the patients with PMV (77.77%). The typical parachute deformity of the mitral valve is best demonstrated in parasternal short axis views of the left ventricle (LV): a single papillary muscle is confirmed at the mid- level of LV (Fig. 2), and the typical “parachute leaflets” are noted at the basal level short axis view. In addition, a long axis of the LV confirms a single papil-
Figure 2. Transthroacic echocardiogram of patient with PMV (A) compared with normal mitral valve (B) at the papillary muscle level of LV short axis view. LV = left ventricle; RV = right ventricle; SPM = single papillary muscle; PM = posteromedial papillary muscle; AL = anterolateral papillary muscle.
Figure 3. Transesophageal echocardiogram (transgastric 0 degree view) of the mid-level of the LV short axis shows a thickened single papillary muscle (arrow) in posteromedial part of the left ventricle (LV). RV = right ventricle; ANT = anterior wall of the LV.
lary muscle accepting all the chordae tendinae insertions. Currently, two-dimensional Doppler echocardiography is the diagnostic method of choice16 whereas TEE is confirmatory in more challenging cases suspected on TTE imaging (Figs. 3 and 4).8,9,12,14 This study shows the incremental value of TEE compared with TTE in two (28.57%) out of seven echo cases.8,11 The PMV may have mimickers such as a pseudo-parachute or parachute-like-mitral valve where chordae tendinae are attached to major papillary muscles and the other being hypoplastic and close to the major one. Careful interrogation by echocardiography that often requires TEE will identify the differences between true parachute and parachute-like mitral valve. Echocardiography helps to define the functional status of the mitral valve and to define other associated cardiac anomalies. MRI and multidetector computed tomography may be
Figure 4. Transesophageal echocardiogram (transgastric 109 degree view) reveals single papillary muscle, where all the chordae tendinae inserted (arrow). LV = left ventricle; LA = left atrium; ANT = anterior wall of the LV.
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reasonable complementary imaging techniques in patients with poor echocardiographic acoustic qualities.17 Adult patients with isolated PMV usually present with dyspnea and have hemodynamically significant lesions of variable severity across mitral valve.6,8,9 However, may be incidentally diagnosed during echocardiography with normal hemodynamics across the mitral valve.10 Such patients generally require no medical or surgical treatment. MVR or repair when feasible needs to be performed only in those patients with hemodynamically significant stenosis or regurgitation.18 Surgical correction of associated congenital cardiac lesion should be performed only if such lesions are hemodynamically significant and account for symptoms. Limitations: This study is a systematic overview of literature, which by definition means that asymptomatic cases will likely be under represented. The rarity of adult PMV lends itself nicely to scrutiny with the research methodology of a qualitative systematic overview. Conclusions: Adult PMV is an uncommon condition with only nine cases identified after a systematic literature review over the last half century. Asymptomatic patients may be discovered incidentally. Mitral stenosis is the usual abnormality in symptomatic patients, with atrial fibrillation or dyspnea being the presenting symptoms. Sudden death can occur. Half of the cases identified required MVR. These findings are in contrast to the pediatric age group. An international registry of adults with PMV from the American and European societies of echocardiography will go a long way to improve diagnosis and give insights into the natural history of this uncommon condition. References 1. Davachi F, Moller JH, Edwards JE: Diseases of the mitral valve in infancy. An anatomic analysis of 55 cases. Circulation 1971;43:565–579.
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2. Oosthoek PW, Wenink AC, Wisse LJ, et al: Development of the papillary muscles of the mitral valve: Morphogenetic background of parachute-like asymmetric mitral valves and other mitral valve anomalies. J Thorac Cardiovasc Surg 1998;116:36–46. 3. Shone JD, Sellers RD, Anderson RC, et al: The developmental complex of “parachute mitral valve,” supravalvular ring of left atrium, subaortic stenosis, and coarctation of aorta. Am J Cardiol 1963;11:714–725. 4. Schaverien MV, Freedom RM, McCrindle BW: Independent factors associated with outcomes of parachute mitral valve in 84 patients. Circulation 2004;109:2309– 2313. 5. Bolling SF, Iannettoni MD, Dick M, 2nd, et al: Shone’s anomaly: Operative results and late outcome. Ann Thorac Surg 1990;49:887–893. 6. Glancy DL, Chang MY, Dorney ER, et al: Parachute mitral valve. Further observations and associated lesions. Am J Cardiol 1971;27:309–313. 7. da Silva CL, Edwards JE: Parachute mitral valve in an adult. Arq Bras Cardiol 1973;26:149–153. 8. Shapira OM, Connelly GP, Shemin RJ: Ischemic papillary muscle dysfunction in an adult with a parachute mitral valve. J Cardiovasc Surg (Torino) 1995;36:163–165. 9. Fitzsimons B, Koch CG: Parachute mitral valve. Anesth Analg 2005;101:1613–1614. 10. Patsouras D, Korantzopoulos P, Kountouris E, et al: Isolated parachute mitral valve as an incidental finding in an asymptomatic hypertensive adult. Clin Res Cardiol 2007;96:38–41. 11. Yesilbursa D, Miller A, Nanda NC, et al: Echocardiographic diagnosis of a stenotic double orifice parachute mitral valve with a single papillary muscle. Echocardiography 2000;17:349–352. 12. Prunier F, Furber AP, Laporte J, et al: Discovery of a parachute mitral valve complex (Shone’s anomaly) in an adult. Echocardiography 2001;18:179–182. 13. Park SJ, Kwak CH, Hwang JY: Long-term survival in double inlet left ventricle combined with pulmonary stenosis and parachute mitral valve: A rare case. Int Heart J 2007;48:261–267. 14. Abelson M: Parachute mitral valve and a large ventricular septal defect in an asymptomatic adult. Cardiovasc J S Afr 2001;12:212–214. 15. Koelble N, Weiss BM, Wisser J, et al: Shone’s anomaly complicated by ascending aortic aneurysm in a pregnant woman. J Cardiothorac Vasc Anesth 2001;15:84–87. 16. Grenadier E, Sahn DJ, Valdes-Cruz LM, et al: Twodimensional echo Doppler study of congenital disorders of the mitral valve. Am Heart J 1984;107:319–325. 17. Ucar O, Vural M, Cicekcioglu H, et al: Mutidetector CT presentation of parachute-like asymtetric mitral valve. Br J Radiol 2008;81:266–268. 18. Coles JG, Williams WG, Watanabe T, et al: Surgical experience with reparative techniques in patients with congenital mitral valvular anomalies. Circulation 1987;76 (3 Pt 2):III117–III122.
