Cleft mitral valve without ostium primum defect: anatomic data and surgical considerations based on 41 cases

Area of Science:

• Cardiology
• Congenital Heart Disease
• Cardiac Surgery

Background:

• Isolated cleft mitral valve (ICMV) morphology and operability are not fully understood.
• ICMV can occur without an ostium primum defect, presenting unique diagnostic and therapeutic challenges.

Purpose of the Study:

• To delineate the distinct anatomic subtypes of isolated cleft mitral valve.
• To correlate specific anatomic features with associated cardiac anomalies.
• To inform surgical strategies based on precise diagnosis.

Main Methods:

• Analysis of anatomic findings in 36 postmortem cases and 5 explanted hearts.
• Review of clinical data, including cardiac catheterization (29 cases) and echocardiograms (13 cases).

Main Results:

• Two main anatomic types identified: canal type (similar to atrioventricular canal defects) and abnormal conus type.
• Canal type cases often present with normally related great arteries and can lead to mitral regurgitation treatable by cleft closure.
• Abnormal conus type cases feature abnormal ventriculoarterial relationships, potentially causing left ventricular outflow tract obstruction not resolved by cleft repair.

Conclusions:

• Isolated cleft mitral valve comprises two distinct anatomic entities: canal type and abnormal conus type.
• Accurate diagnosis of associated ventriculoarterial relationships is essential for guiding surgical management.
• Differentiating these types impacts surgical planning and prognosis, particularly regarding outflow tract obstruction.