VSD Patch Closure — #1 Anterosuperior Portion (Surgeon’s View)

Orientation and Rationale

In perimembranous ventricular septal defects (pmVSDs), the anterosuperior margin courses toward the junction of the trabecula septomarginalis (TSM) and infundibular (conal) septum and lies away from the atrioventricular conduction axis, which typically runs along the postero-inferior rim where fibrous continuity forms part of the central fibrous body [1, 2]. This anatomic reality permits confident advancement of the anterosuperior suture line—provided meticulous protection of the aortic cusp insertions and annulus.

Objectives at this Margin

1. Seal the LV–RV communication without violating the aortic annulus or leaflet tissue [1].
2. Preserve leaflet geometry/coaptation by avoiding leaflet capture, cusp tether, or annular distortion.
3. Set up a tension-free turn into the conduction-adjacent posterior/inferior arc, where bite depth and spacing must be deliberately conservative [2, 5, 6].

Exposure and Landmarks

• Right atrial approach and global plan. Standard exposure is via a right atriotomy through the tricuspid valve; either running or interrupted patch fixation is acceptable and should be tailored to anatomy and surgeon preference [3].
• Aortic relationship. Continuously identify the right (and variably non-coronary) cusp and any commissural proximity or cusp prolapse. When in doubt, reassess leaflet mobility under direct vision before committing a bite [1, 2].
• TSM–infundibular junction. This transition zone offers robust tissue but demands orthogonal needle passage to avoid skiving into trabeculations or drifting toward the aortic annulus.
• Optimizing exposure. If visualization of the subaortic angle is limited, temporary detachment of the tricuspid anterior leaflet can improve exposure with excellent valvar outcomes and minimal conduction jeopardy—preferable to septal leaflet detachment in many pmVSDs [4].

Patch Placement and Suture Strategy (Anterior–Superior Arc)

• Patch delivery. “Parachute” the patch onto the anterior rim after initial anchors. Ensure the leading edge sits flush on the LV septal face—no tenting toward the aortic root.
• Bite geometry. Use perpendicular, full-thickness septal bites with consistent LV-side purchase. Maintain a visible safety offset from the aortic annulus; at commissures, angle the needle away from cusp insertion and confirm the exit point before committing.
• Suture mode. Along this conduction-safe arc, a fine, pledget-sparing running line often yields a smoother lay; use targeted interrupted reinforcements at irregular segments (e.g., TSM corner). Either technique is acceptable within a coherent, low-tension construct [3, 5].
• Suture management. Park tails on the right atrial side and delay final tying until the posterior/inferior segment is completed to keep the aortic rim uncluttered.

Pitfalls and Targeted Countermeasures

• Leaflet entrapment or distortion. Most commonly from bites too near the annulus or the patch edge sliding under a cusp. Countermeasures: keep an annular standoff, intermittently probe leaflet mobility, re-seat the patch if tethering appears [1].
• Residual anterosuperior leak. Usually due to shallow trabecular bites or a “step-off” at the TSM junction. Countermeasures: ensure orthogonal needle trajectory, consider a short reinforcing stitch at the transition, and verify a smooth patch-rim interface.
• Aortic regurgitation. New central/commissural AI suggests cusp injury or annular distortion. Countermeasures: reassess coaptation before leaving this arc; if doubtful, remove and re-place the offending stitch with greater annular clearance [1].

Conduction-Safety Perspective (Why the Anterior Arc Matters)

Although the anterosuperior segment is distant from the conduction bundle, its geometry determines how safely you turn onto the posterior/inferior rim, where the conduction axis hugs the fibrous postero-inferior border of pmVSDs. A disciplined anterior line that preserves leaflet mechanics enables shallow, rim-hugging bites posteriorly—an approach linked to lower right bundle branch injury and avoidance of complete heart block [2, 5, 6].

Technique Options in Context (Surgery vs. Devices—Implications for the Anterior Arc)

• Surgical closure via right atrial exposure remains the reference standard across age groups; both interrupted and running strategies are acceptable when executed with appropriate bite size and spacing near conduction tissue [3, 5].
• Transcatheter alternatives (including eccentric and duct-occluder devices) can be effective in carefully selected pmVSDs but carry a non-negligible risk of complete AV block and device-related valvar interference, particularly in younger children and in defects with cusp prolapse or inlet extension. These risks underscore the premium on precise leaflet protection and annular respect when operating at the anterosuperior margin—even if a device approach is contemplated for the case mix at your center [7, 8].

Pearl: Treat the anterosuperior margin as the “setup stroke.” It is the safest arc for conduction—but the least forgiving for aortic valvar mechanics. A clean, annulus-respecting anterior line pays dividends when you turn the corner into the conduction neighborhood

References

[1] Ho SY, McCarthy KP, Rigby ML. Morphology of perimembranous ventricular septal defects: implications for transcatheter device closure. J Interv Cardiol. 2004;17(2):99-108. PubMed

[2] Spicer DE, Bridgeman JM, Brown NA, Mohun TJ, Anderson RH. Ventricular septal defect. Anatol Rec (Hoboken). 2014;297(7):1169-1193. (Open-access review detailing pmVSD borders and conduction axis location.) PMC

[3] Manning PB. Ventricular Septal Defect Closure: How I Teach It. Ann Thorac Surg. 2018;106(2):324-326. PubMed

[4] Maile S, Kadner A, Turina MI, Prêtre R. Detachment of the anterior leaflet of the tricuspid valve to expose perimembranous ventricular septal defects. Ann Thorac Surg. 2003;75(3):944-946. PubMed

[5] Mullen JC, Lemermeyer G, Schipper SA, Bentley MJ. Perimembranous ventricular septal defect repair: keeping it simple. Can J Cardiol. 1996;12(9):817-821. PubMed

[6] Fukuda T, Suzuki T, Kashima I, Sato M, Morikawa Y. Shallow stitching close to the rim of the ventricular septal defect eliminates injury to the right bundle branch. Ann Thorac Surg. 2002;74(2):550-555. PubMed

[7] Butera G, Carminati M, Chessa M, et al. Transcatheter closure of perimembranous ventricular septal defects: early and long-term results. J Am Coll Cardiol. 2007;50(12):1189-1195. PubMed

[8] Holzer R, de Giovanni J, Walsh KP, et al. Transcatheter closure of perimembranous ventricular septal defects using the Amplatzer membranous VSD occluder: immediate and midterm results of an international registry. Catheter Cardiovasc Interv. 2006;68(4):620-628. PubMed