Anatomy
This combination of defects can include any combination along both the CAVC and TOF spectrum. In most cases, the AVC defect is balanced (Rastelli type C or B) and the VSD component includes an inlet portion combined with a conoventricular defect. The location of RVOTO can be subvalvar, valvar, or supravalvar and may be hemodynamically significant.
Pathophysiology
Most patients with TOF/CAVC have a large VSD, establishing a substrate for a large ventricular level shunt. However, RVOTO may be protective from excessive pulmonary blood flow and may delay or prevent the onset of congestive heart failure when AVVR is not severe. Rarely, RVOTO is sufficiently severe to cause hypoxemia. Rarely, in the absence of significant RVOTO, TOF/CAVC can cause significant heart failure in early life.
TOF/CAVC Repair
Postoperative considerations
Many patients following TOF/CAVCexhibit restrictive right ventricular physiology due to a large VSD patch (as well as an infundibular patch). This may manifest as significant right atrial hypertension (RAP >5-8 mmHg), which in severe cases may be symptomatic (ascites, renal or hepatic dysfunction, chylous effusion). The presence of a transannular pulmonary patch (and free PR) may exacerbate low cardiac output. Because T21 is a common comorbidity, consider macroglossia (and therefore patient positioning and sedation) and subglottic stenosis at the time of exutbation.
Is there residual mitral regurgitation? The most important and common residual defect following any AVC repair is mitral regurgitation. While the goal is to close the cleft (i.e. the space between the SBL and IBL) completely, this may leave a stenotic MV, so sometimes MR through a residual cleft is unavoidable. In these cases, aggressive BP control, early diuresis, and sedation (with or without NMB) may promote recovery.
Is there a residual VSD? Rarely, there are additional muscular VSDs or residual VSD which may raise LAP and slow extubation.
Is there heart block or junctional rhythm? Proximity of the AV node to the ASD1 suture line make heart block or junctional rhythm possible.