Author + information
- Received March 25, 2003
- Revision received June 19, 2003
- Accepted July 13, 2003
- Published online December 3, 2003.
- Alain Fraisse, MD*,* (, )
- Tony Abdel Massih, MD†,
- Bernard Kreitmann, MD*,
- Dominique Metras, MD*,
- Pascal Vouhé, MD†,
- Daniel Sidi, MD† and
- Damien Bonnet, MD†
- ↵*Reprint requests and correspondence:
Dr. Alain Fraisse, Service de Cardiologie A, Hôpital de la Timone, 13005 Marseille, France.
Objectives We sought to highlight the clinical, morphologic, and pathogenetic features in patients with a cleft mitral valve (MV).
Background Few studies have addressed the morphologic features of cleft MV and the outcome of these patients. The pathogenetic features, including the developmental relation to an atrioventricular (AV) septal defect, remain unclear.
Methods We reviewed the patients with cleft MV that were diagnosed by echocardiography since 1980. Patients with an AV canal, ventriculo-arterial discordance, and hypoplastic ventricles were excluded.
Results Twenty-two patients were identified at a median age of 0.5 years (range 0 to 10.6). In three patients, no chordal attachments of the cleft to the ventricular septum were seen. Ten patients had significant mitral regurgitation (MR), and three had subaortic obstruction by the cleft. Associated cardiac lesions and extracardiac features were present in 13 and 10 patients, respectively. During the median follow-up period of 1.5 years (range 0 to 11.8), two patients died of extracardiac causes, and one neonate died of severe subaortic obstruction. Surgical repair was performed in 10 patients at a median age of 5.2 years (range 1.3 to 10.6). Multivariate analysis showed no predictors for MV surgery. One patient was re-operated for mitral stenosis associated with aortic valve stenosis. Follow-up echocardiography demonstrated moderate MR in two unoperated patients and moderate MV stenosis in two operated patients.
Conclusions A cleft of the MV comprises a wide spectrum. Important morphologic differences exist with an AV septal defect, although the two lesions may be pathogenetically related. Surgical repair always seems possible. Long-term echocardiographic follow-up is warranted.
A relatively uncommon lesion, such as a cleft of the mitral valve (MV), is morphologically different from a cleft of the left-sided valve of an atrioventricular (AV) septal defect because of the absence of a common AV junction (1–11). It is observed when there is mitral regurgitation (MR), subaortic stenosis, or associated lesions (1–3,6–8). However, part of its anatomic spectrum is not well described, such as chordal attachments and the position of the cleft (5–8). Also, the developmental relation to an AV septal defect remains unclear. Moreover, data on mid-term outcome are scarce, and only few reports have addressed the surgical issues of patients with cleft MV (6,8,11). We reviewed our experience to highlight the clinical, morphologic, and pathogenetic features of patients with a cleft MV and to report their mid-term outcome.
We searched in our computerized database for all patients with a cleft MV diagnosed by echocardiography since 1980 in the Pediatric Cardiology Department, Hôpital Necker/Enfants Malades, Paris, or Hôpital de la Timone-Enfants, Marseille. We excluded all patients with AV septal defect features on the echocardiogram: a deficiency of the inlet portion of the ventricular septum with a left ventricle inlet/outlet ratio <1, cleft bridging over an inlet ventricular septum, and counterclockwise rotation of the left ventricular papillary muscles with a smaller mural leaflet. Patients with unbalanced ventricles and/or abnormal ventriculo-arterial connections were also excluded. The severity of MR was assessed semiquantitatively (graded as none, mild, moderate, or severe, according to the jet width at its origin and area, as seen by color Doppler flow mapping). A subaortic obstruction was defined as a peak Doppler gradient >20 mm Hg.
To identify the risk factors for surgery of the cleft MV itself, we used the Fisher exact test for univariate analysis and logistic regression for multivariate analysis. A p value <0.05 was considered statistically significant.
A cleft of the MV was diagnosed in 22 patients at a median age of 0.5 years (range 0 to 10.6). Table 1summarizes the clinical and morphologic features of the patients. There were 12 males and 10 females. The median age and weight at presentation were 0.2 year (range 0 to 10) and 4.8 kg (range 2.5 to 30), respectively. Eleven patients presented with symptoms due to MR (n = 6), MR and severe subaortic stenosis (n = 1), and associated lesions (n = 4). The median QRS axis on the electrocardiogram was 50° (range −170° to 130°). Echocardiography revealed in all patients a cleft dividing the anterior (aortic) leaflet of the MV into two (Figs. 1 and 2), ⇓⇓with attachments of its components to the perimembranous ventricular septum in 19 patients (Fig. 1). In three patients with moderate to severe MR, no chordal attachments to the ventricular septum were seen (Fig. 2). No patient had echocardiographic features of an AV septal defect. Associated cardiac lesions were present in 13 patients, most frequently a ventricular septal defect (n = 6). Ten patients had moderate to severe MR by color Doppler imaging, with an anterior leaflet prolapse in two. A subaortic stenosis was demonstrated in four patients, due to chordal attachments to the ventricular septum in three patients (Fig. 1) and to a subaortic membrane in one patient. Various extracardiac abnormalities were found in 10 patients (Table 1).
The median follow-up period was 1.5 years (range 0 to 11.8). Three patients died early after presentation. A two-month-old infant with Down syndrome died suddenly at home. He had a clinically well-tolerated cleft MV with mild MR, a patent ductus arteriosus, and an ostium secundum atrial septal defect. The second patient presented at two days of life with severe congestive heart failure. Echocardiography showed moderate to severe MR and severe subaortic stenosis due to the chordal attachments of the cleft. He suddenly collapsed after two days of mechanical ventilation and could not be resuscitated. An autopsy showed severe subaortic stenosis due to accessory chordal attachments to the ventricular septum. A third patient with trisomy 18 died suddenly at the age of one month.
Mitral valve repair was performed in 10 patients (Table 2) at a median age of 5.2 years (range 1.3 to 10.6). The surgery was indicated electively in five patients because of symptoms due to MR (n = 3) and associated cardiac lesions (n = 2). The median cardiopulmonary bypass and aortic cross-clamp times were 78.5 min (range 68 to 114) and 47 min (range 36 to 71), respectively. In the three patients without attachments of the cleft, an intraoperative examination confirmed the absence of any accessory chordal attachments (Fig. 2B and 3). ⇓In one of them, the cleft was incomplete (Fig. 3). In 8 of the 10 patients, a suture of the cleft edges was accomplished. In one patient, a pericardial patch enlargement of the anterior leaflet was performed. In another patient with severe MR and retraction of the cleft edges (Fig. 2), the proximal part of the cleft was closed, and a double-orifice MV was surgically created by anchoring the top edge of the posterior (mural) leaflet to the free edges of the distal cleft (Alfieri type repair). Mitral annuloplasty was associated in three patients. In two patients, it was necessary to resect the chordal attachments to the ventricular septum because of subaortic stenosis. Besides MV repair, other surgical procedures were performed for associated cardiac lesions in seven patients (Table 2). Two patients underwent cardiac surgery before the cleft MV was diagnosed: one 3.5-year-old patient with tetralogy of Fallot and an absent pulmonary valve and one two-month-old infant with aortic valve stenosis. In both cases, the cleft was repaired after the first surgery because of symptoms with worsening MR. The patient with aortic stenosis had a Ross procedure associated with removal of the mitral annuloplasty ring at nine years of age for moderate mitral stenosis and severe aortic stenosis. There was no other re-operation after MV repair.
Multivariate analysis of the 19 surviving patients showed no clinical or morphologic predictors for surgery of the MV, although there was a borderline relationship for patients with moderate to severe MR (p = 0.07).
At the most recent follow-up, the 19 surviving patients were all in New York Heart Association functional class I. Two unoperated patients have moderate MR. None of the 10 patients who underwent MV repair have more than mild MR or subaortic stenosis due to the MV. Two operated patients have moderate mitral stenosis.
Diagnosis and morphologic considerations
Echocardiography gives the opportunity to diagnose cleft MV with greater frequency than before. However, in younger patients with an isolated cleft, mild MR, and no subaortic stenosis, it may remain undiagnosed for many years. In cleft MV, the anterior leaflet is almost always involved (2–11), although a cleft in the posterior (mural) leaflet has been described (10). A recent study of an autopsied specimen and echocardiogram emphasized the difference with the cleft seen in AV septal defects (5). In the former, the cleft leaflet is supported by a normal left AV junction, with a posterior leaflet comparable in size to the dimension seen in a normal MV (5). In the AV septal defect, the left valve is part of a common AV valve, and the leaflets of the valve bridge, or tend to bridge (in the partial form), the inlet ventricular septum. The papillary muscles are positioned laterally with a smaller mural leaflet (5–7,9). The cleft points toward the inlet septum (3,4,8). In our patients, the cleft was clearly in a more anterior direction toward the aortic root (Fig. 1), as it was noticed in previous echocardiographic and postmortem studies (3,5,6,8,11), although this position may vary according to precise echocardiographic measurements performed by Khol and Silverman (7).
In our study, we did not find any chordal attachments of the cleft to the ventricular septum in three patients, whereas other investigators have described these chordal attachments as a constant finding (6,7). In their echocardiographic study, Khol and Silverman (7)stated, “without such attachment, the divided anterior leaflet would be flail.” In our three patients, the absence of any accessory chordae by echocardiography was confirmed intraoperatively (Figs. 2 and 3), as it was also reported by Perier and Clausnitzer (11). In these patients without chordal attachments of the cleft, the MR was severe in two patients and moderate in one patient with a limited extension of the cleft toward the base of the anterior MV leaflet (Fig. 3). Similar cases of “incomplete” cleft were also noticed in Perier's study (11).
Despite the fundamental morphologic differences between these two entities, it remains unclear whether an AV septal defect and cleft MV share a common embryologic background. One view is that both lesions result from failure of fusion of the embryologic AV endocardial cushions. Cleft MV may represent a “forme-fruste” of an AV septal defect (9). However, microscopic examination of serial sections of human embryos indicates that the AV septal defect results from a deficiency of the inlet septum, whereas cleft MV is caused by a failure of the endocardial cushions to seal together the two components of the anterior leaflet of the MV (4). Interestingly, in our study, children with cleft MV have a comparable frequency and type of associated extracardiac anomalies as in an AV septal defect. As in cleft MV in the present study, the AV canal is present in children with Down syndrome (12), trisomy 18 (12), and Noonan syndrome (13). Some previously published series reported a 10% to 25% occurrence of Down syndrome in patients with cleft MV (5,6,9). Thus, the association of cleft MV with genetic syndromes traditionally associated with an AV septal defect suggests a possible genetic and causative connection between the two defects.
Surgical considerations and outcome
Differentiation between the cleft of an otherwise normal MV and the cleft seen in AV septal defects is important for indication and conduction of surgical repair. First, in patients with MR and an AV septal defect, the smaller size of the mural leaflet, along with two closely spaced papillary muscles, may complicate the repair. Inaccurate cleft approximation may result postoperatively in significant MR or stenosis after insufficient or excessive closure. In the cleft with an otherwise normal MV, surgical repair is generally accomplished by suturing the cleft (6,11). The annulus is of a normal size or dilated, and the posterior (mural) leaflet is normally developed (Fig. 1). Suturing the edges of the cleft should not theoretically induce mitral stenosis. Second, in patients with subaortic stenosis, the mechanism is complex in an AV septal defect. Fibromuscular narrowing, subaortic ridges, chordal tissue, or abnormal papillary muscle can exist isolated or in combination (14). Surgical relief is often accomplished through the aortic valve. In the cleft with a normal MV, a subaortic obstruction is generally due to the chordal attachments of the cleft (5,8). Surgical relief is performed by resection of these accessory chordae. Finally, in an AV septal defect, the conduction tissue is exposed on the crest of an associated inlet ventricular septal defect during surgical repair (5,7), whereas it follows a usual pattern in cleft MV (5).
The age at presentation in our study patients ranged from 0 to 10.6 years, related in some cases to the various functional consequences of the associated cardiac lesions and to extracardiac genetic features. As in previously reported studies (3,6,8,11), MV repair was feasible in all patients and was indicated in children with symptoms and/or moderate MR by echocardiography. A direct and complete suture of the cleft was accomplished in the majority. However, in two patients, the suture of the cleft was impossible because of retraction of both parts of the anterior MV leaflet (Fig. 2). Augmentation of the anterior leaflet with a pericardial patch was accomplished in one patient, whereas the other patient had an Alfieri procedure. As a relationship between the age of the patients and the thickness of the cleft edges exists (9), the need for patch material to repair the MV seems to increase in longstanding MR and with older age at repair (11). Surgical repair should then be advocated in older children, even without symptoms.
A cleft of the anterior MV leaflet comprises a wide clinical spectrum with various associated cardiac and extracardiac features. There are important morphologic differences of surgical relevance between cleft MV and AV septal defect, although the two lesions may be pathogenetically related. Surgical repair always seems possible with a good functional result and may be indicated early in life. Management of associated cardiac lesions and extracardiac features is often necessary. Long-term clinic and echocardiographic follow-up of the operated and unoperated patients is warranted.
- mitral regurgitation
- mitral valve
- Received March 25, 2003.
- Revision received June 19, 2003.
- Accepted July 13, 2003.
- American College of Cardiology Foundation
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