11.1 Arterial Switch Operation (Jatene) & Lecompte Maneuver Evaluation

11.1 Arterial Switch Operation (Jatene) & Lecompte Maneuver Evaluation

Clinical Core: The Arterial Switch Operation (ASO), pioneered by Adib Jatene in 1975, is the definitive anatomical repair for d-Transposition of the Great Arteries (d-TGA) with intact ventricular septum (IVS) or ventricular septal defect (VSD). By translocating the great arteries and reimplanting the coronary artery buttons, the ASO restores the morphologically left ventricle (LV) as the systemic pump and the morphologically right ventricle (RV) as the subpulmonary pump. For the pediatric echocardiographer, lifelong surveillance centers on four major anatomical targets: neoaortic root dilation and regurgitation, neopulmonary outflow and branch pulmonary artery stenosis (the Lecompte consequence), coronary artery patency and myocardial perfusion, and residual intracardiac shunts.

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Surgical Mechanics of the Jatene Procedure

Unlike atrial switch procedures (Mustard and Senning) that achieve physiological correction by redirecting venous inflow while leaving ventriculoarterial discordance intact, the Arterial Switch Operation achieves complete anatomical correction. The surgery is ideally performed within the first 2 to 3 weeks of life, before neonatal pulmonary vascular resistance falls and the LV regresses (loses the muscle mass and wall thickness required to generate systemic afterload).

Native d-TGA Anatomy:                    Post-Jatene Anatomical Repair:

   [Morphologic RV] ──► [Aorta]             [Morphologic RV] ──► [Neopulmonary Artery]
   [Morphologic LV] ──► [Pulmonary Trunk]   [Morphologic LV] ──► [Neoaorta (Systemic)]
       (Discordant Connections)                 (Concordant Connections Restored)

Critical Operative Steps

1. Assessment of Left Ventricular Preparation: In infants presenting beyond 3 to 4 weeks of life with d-TGA and intact ventricular septum, the left ventricle has been pumping against low pulmonary vascular resistance and rapidly undergoes muscular deconditioning. The LV mass index must exceed 35 to 40 g/m², and the LV cavity must maintain an elliptical shape without banana-like septal flattening into the LV during systole. If the LV has regressed, a staged approach with preliminary pulmonary artery banding (± systemic-to-pulmonary shunt) is required to "train" the LV before the arterial switch.
2. Transection of the Great Arteries: Both the aorta and the main pulmonary artery (MPA) are transected several millimeters above their respective semilunar valve commissures.
3. Coronary Button Excision and Translocation: The left and right coronary ostia are harvested from the native aortic root with generous surrounding buttons of aortic wall. Small "trapdoor" or circular incisions are excised in the native pulmonary root (the neoaortic root), and the coronary buttons are translocated and anastomosed onto this new systemic root. This is the most technically demanding phase of the operation; coronary stretching, kinking, torsion, or excessive tension can precipitate acute intraoperative or delayed postoperative myocardial infarction.
4. The Lecompte Maneuver: In the vast majority of cases where great arteries are in standard anteroposterior alignment, the pulmonary artery bifurcation is pulled anteriorly over the reconstructed neoaorta. This brings the pulmonary bifurcation anterior to the neoaortic root, eliminating the need for prosthetic conduit interposition.
5. Neoaortic Anastomosis: The native pulmonary root (now functioning as the neoaortic root) is anastomosed directly to the distal ascending aorta (native aortic arch and descending aorta).
6. Neopulmonary Reconstruction: The native aortic root, now missing its coronary buttons, is reconstructed using a single pant-leg pericardial patch or two separate autologous pericardial patches to fill the button harvest defects. The reconstructed root (now the neopulmonary root) is then anastomosed to the anteriorly transposed pulmonary bifurcation.
7. Intracardiac Shunt Closure: Associated defects, including patent foramen ovale (PFO), atrial septal defect (ASD), ventricular septal defect (VSD), or patent ductus arteriosus (PDA), are closed with direct sutures or patch repair.

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The Lecompte Maneuver: Anatomy, Pathomechanics & Complications

Introduced by Yves Lecompte in 1981, the Lecompte maneuver is one of the pivotal innovations that made the arterial switch operation universally feasible without prosthetic conduits. However, this maneuver creates unique anatomical relationships that define the majority of late re-interventions:

Anterior Translocation of the Pulmonary Bifurcation (The Lecompte Maneuver):

             [Trachea / Bronchi]
                     │
                     ▼
         [Right Pulmonary Artery (RPA)] ──► Courses behind Ascending Neoaorta
                     │
       ┌─────────────┴─────────────┐
       ▼                           ▼
[Ascending Neoaorta]       [Left Pulmonary Artery (LPA)]
 (High-Pressure Cylinder)    (Draped Tightly over Neoaorta)
       ▲
       │
[Pulmonary Trunk Bifurcation]
  (Translocated ANTERIOR to Neoaorta)

Anatomic Consequences of the Lecompte Maneuver

• Pulmonary Trunk Position: The reconstructed main pulmonary artery bifurcation sits directly anterior to the neoaorta.
• Left Pulmonary Artery (LPA) Draping: The LPA courses over the left superior aspect of the neoaorta to reach the left lung hilum. As the child grows and the neoaortic root expands, the LPA is stretched and flattened against the rigid neoaorta and the left mainstem bronchus, predisposing to ostial narrowing, tubular hypoplasia, and acute angulation.
• Right Pulmonary Artery (RPA) Compression: The RPA must pass behind the neoaorta and anterior to the tracheal bifurcation. Neoaortic enlargement can compress the RPA against the trachea or right main bronchus.
• When is the Lecompte Maneuver Omitted? When the great arteries are in a side-by-side relationship or when the aorta is situated posterior to the pulmonary artery, attempting a Lecompte maneuver would twist or stretch the branch pulmonary arteries excessively. In these cases, the arteries are anastomosed without translocation (aorta remaining posterior/lateral and pulmonary artery anterior/medial), sometimes requiring an interposition tube graft or pericardial roll.

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Comprehensive Postoperative Echocardiographic Surveillance Protocol

Postoperative evaluation requires a disciplined, multi-window approach addressing specific anatomical and functional risks.

1. Neoaortic Root & Valve Surveillance

The neoaortic valve and root are derived from the patient's native pulmonary valve and pulmonary root. Histologically, the native pulmonary root possesses thinner elastic media and less adventitial collagen than a normal native aorta. When subjected to lifelong systemic arterial pressures, progressive structural remodeling ensues:

• Progressive Neoaortic Root Dilation: A substantial proportion of post-ASO patients develop progressive dilation of the neo-annulus, neo-sinuses of Valsalva, and neo-sinotubular junction. Serial measurements of the neoaortic root must be indexed to body surface area (BSA) and expressed as Z-scores. A sinus of Valsalva Z-score exceeding +3.0 indicates marked dilation requiring close serial monitoring for dissection risk or impending valve failure.
• Neoaortic Valve Regurgitation (AR): Root dilation stretches the semilunar commissures, preventing central leaflet coaptation. Contributing factors include geometric mismatch between the native pulmonary root and distal transected aorta, surgical traction during coronary button harvest, or pre-existing pulmonary valve pathology (e.g., bicuspid neoaortic valve).
• Echocardiographic Quantification of AR:
  • Parasternal long-axis view: Measure the color Doppler jet width relative to the neoaortic LVOT diameter (jet width/LVOT ratio: mild <25%, moderate 25–64%, severe ≥65%).
  • Apical 5-chamber and 3-chamber views: Continuous-wave (CW) Doppler pressure half-time (PHT: severe <200 ms, mild >500 ms).
  • Suprasternal and subcostal views: Document holodiastolic retrograde flow (flow reversal) in the descending thoracic or abdominal aorta, signifying hemodynamically significant regurgitation with systemic runoff.

2. Neopulmonary Outflow & Branch Pulmonary Artery Stenosis

Obstruction of the right ventricular outflow tract and pulmonary arterial tree represents the single most common long-term complication after the Jatene procedure, accounting for over 70% to 80% of all post-ASO re-interventions:

• Supravalvar Pulmonary Stenosis (SVPS): Stenosis frequently occurs at the site of the neopulmonary surgical anastomosis or pericardial patch reconstruction in the main pulmonary artery. Fibrotic cicatrization and shrinkage of the pericardial patch over time create circumferential narrowing.
• Branch Pulmonary Artery Stenosis (The Lecompte Consequence): The Lecompte maneuver pulls the pulmonary bifurcation anteriorly, causing the left pulmonary artery (LPA) and right pulmonary artery (RPA) to straddle the rigid, high-pressure neoaorta like a pair of rider's legs around a horse:
  • Left Pulmonary Artery (LPA): Drapes tightly over the left superior aspect of the neoaorta. It is particularly vulnerable to extrinsic compression, acute angulation, and severe ostial or proximal tubular hypoplasia.
  • Right Pulmonary Artery (RPA): Courses behind the neoaorta and anterior to the trachea and right main bronchus, where it can suffer retro-aortic compression.
• Doppler Interrogation Protocol:
  • High parasternal short-axis, high left parasternal "ductal" view, and suprasternal notch coronal views are mandatory.
  • Color Doppler reveals intense turbulence and aliasing across the main PA and branch origins.
  • CW Doppler must be aligned parallel to flow in both the proximal LPA and RPA. A peak velocity exceeding 3.0 to 3.5 m/s (peak gradient >36 to 49 mmHg) or a mean gradient exceeding 20 mmHg indicates hemodynamically significant stenosis warranting cardiac catheterization with balloon or stent angioplasty.
  • Sonographers must estimate right ventricular systolic pressure (RVSP) via the tricuspid regurgitation (TR) continuous-wave Doppler jet ($4V^2 + RAP$). If RVSP exceeds two-thirds of systemic systolic blood pressure, outflow obstruction is severe.

3. Coronary Artery Patency & Myocardial Perfusion Surveillance

Coronary complications are the primary cause of acute perioperative mortality and chronic occult myocardial ischemia in post-ASO patients:

• Mechanisms of Coronary Compromise: Ostial kinking, torsion/twisting, tension/stretching from neoaortic root dilation, fibrocellular intimal proliferation, or compression against the sternum or neopulmonary trunk. Certain preoperative coronary anatomical variants carry elevated risk, such as a single coronary ostium, an intramural coronary course, or an inverted coronary origin (e.g., circumflex artery originating from the right coronary artery, Leiden classification type 1LCx-2R).
• Direct Coronary Visualization: Using high-frequency pediatric transducers (7 to 12 MHz) in the parasternal short-axis view at the aortic root level, the sonographer must identify both coronary buttons arising from the neoaortic sinuses. Color Doppler with low velocity scale (25 to 40 cm/s) demonstrates laminar systolic-diastolic coronary flow.
• Surveillance for Myocardial Ischemia: Because direct visualization of distal coronary branches is challenging by transthoracic echo, the sonographer must actively interrogate downstream myocardium for ischemic signatures:
  • Regional Wall Motion Abnormalities (RWMA): Interrogate all left ventricular walls (apical 4-chamber, 2-chamber, 3-chamber, and parasternal short-axis at basal, mid, and apical levels). Anterior wall or septal akinesis points to left anterior descending (LAD) artery compromise; inferior/posterior hypokinesis indicates right coronary artery (RCA) compromise; lateral wall abnormalities suggest circumflex (LCx) stenosis.
  • Global Systolic Function: Reductions in fractional shortening (FS < 28%) or biplane Simpson left ventricular ejection fraction (LVEF < 50%).
  • Myocardial Strain (Speckle-Tracking Echocardiography): A novel reduction in left ventricular peak global longitudinal strain (GLS, normally more negative than -18% to -20%; abnormal values worse than -16%, e.g., -11% to -14%) frequently detects subclinical ischemic injury long before ejection fraction declines.
  • Ischemic Mitral Regurgitation: Papillary muscle hypoperfusion causing new apical tethering and mitral insufficiency.

4. Residual Intracardiac Shunts

• Interrogate the ventricular septum in multiple planes (parasternal long-axis, short-axis sweep, apical 4-chamber, subcostal) with color Doppler to exclude residual patch margin leaks or missed muscular VSDs.
• Examine the interatrial septum to confirm competent closure of the PFO or ASD patch, evaluating for residual interatrial left-to-right shunting.

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Arterial Switch Postoperative Complications & Surveillance Protocol

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Clinical Pearls & Sonographic Traps

[!WARNING] The "Pseudo-Normal" LPA Doppler Jet: In patients with severe left pulmonary artery stenosis following the Lecompte maneuver, the proximal LPA may be compressed into a slit-like orifice. If the ultrasound beam is positioned perpendicular to this vessel from a standard parasternal view, the true velocity will be drastically underestimated. Always utilize a high left parasternal window (the "ductal cut") or a suprasternal notch coronal view with continuous-wave Doppler parallel to the long axis of the LPA to capture the true maximum velocity.

[!TIP] The Significance of Diastolic Flow in the PA: When interrogating the neopulmonary anastomosis with spectral Doppler, the presence of continuous or prolonged forward diastolic flow indicates either severe distal pulmonary branch stenosis, severe elevation of pulmonary vascular resistance, or competitive runoff from aortopulmonary collaterals. Always trace the full spectral envelope to calculate mean gradients.

[!NOTE] Z-Score Reporting is Mandatory: In pediatric and adolescent post-ASO surveillance, absolute root dimensions (e.g., neoaortic root = 28 mm) are clinically meaningless without indexing to body surface area. The pediatric sonographer must always compute and report Z-scores for the neoaortic annulus, sinuses of Valsalva, and sinotubular junction to detect pathological root expansion over time.