Transseptal puncture in congenital heart disease
Transcatheter perforation of the atrial septum was first described in 1959,1 and subsequently gained popularity as an alternative to transbronchial or transthoracic access to the left atrium for diagnostic catheterization.2-6
Improved ability to estimate left atrial pressure by pulmonary arterial wedge pressure and hemodynamic assessment by non-invasive echocardiographic Doppler interrogation resulted in a decline in the popularity of the technique. In recent years there has been renewed interest in transseptal puncture of the atrial septum for more accurate hemodynamic assessment and access to the left atrium and ventricle for interventional procedures such as radiofrequency ablation of accessory pathways and arrhythmia control, as well as therapeutic interventional procedures for congenital and structural heart disease. Stenotic aortic valves with significant calcification or vegetations may represent an embolic risk, and the severity of stenosis may preclude accurate retrograde assessment of pressure difference by pullback.7,8 In general, the direct measurement of the atrial pressure is more accurate than wedge pressures for the assessment of mitral valve physiology. Simultaneous measurement of left atrial and left ventricular or left ventricular and aortic pressures will always yield more precise characterization of mitral and aortic valve hemodynamics, respectively. In addition to providing access to the left atrium, transseptal puncture with creation of an atrial defect has been further utilized as a therapeutic strategy for patients with end stage pulmonary hypertension,9-11 patients on mechanical cardiopulmonary support requiring left atrial decompression,9-12 as an adjunct to closure of the long tunnel at times associated with the foramen ovale in cryptogenic stroke,13 and for patients who, by the nature of their congenital heart defect, require an obligatory atrial shunt or mixing for survival14-16 (for example: hypoplastic left heart syndrome, tricuspid stenosis, pulmonary atresia with intact ventricular septum). There has been recent interest in primary intervention on the atrial septum for severe forms of congenital heart disease in utero.14,17 Mechanical perforation of conduits and other surgically created intra-atrial patches has also
been well described.18 A broad list of the indications for transseptal puncture or intervention of the atrial septum is presented in Table 6.1.