DORV #1 — Anatomy + Anatomic Classification (VSD–Outflow Map)
DORV is not a single defect but a mode of ventriculo–arterial connection with broad morphologic expression. The unifying feature is that both arterial trunks arise completely or predominantly from the morphologic right ventricle (RV), producing a wide spectrum of physiologies that can resemble VSD physiology, TOF physiology, TGA physiology, or functional single-ventricle circulation depending on associated anatomy and outflow relationships. [1]
A key practical point is that, in most DORV, the left ventricle (LV) lacks a direct, committed outlet to a great artery; therefore, LV egress depends on an interventricular communication (most commonly a VSD). As a result, the VSD behaves as the functional LV outflow tract, and its commitment and routability are central determinants of repair strategy. [1,2]
1) Core Anatomic Definition (What Must Be True)
1.1 Ventriculo–arterial commitment (definition with nuance)
Many descriptions use a “≥50% commitment” rule (e.g., aortic override) to operationalize DORV, but contemporary morphologic thinking emphasizes that DORV is fundamentally a conotruncal (conal muscle) problem rather than a simple percentage assignment. In practice, conal muscle development and outlet septal relationships define the true operative geometry and explain why “borderline” cases behave differently than their numeric classification might suggest. [3]
1.2 The conus concept and LV–aortic discontinuity (why LVIF matters)
A recurring morphologic theme is conal tissue interposition and outlet (infundibular) malalignment, which often produces loss of fibrous continuity between the mitral and aortic annuli. Functionally, this manifests as a left ventricular infundibular fold (LVIF)—a muscular “wedge” between the LV inflow and the arterial valve plane. [1,3]
Surgical relevance (why you care):
- It affects VSD-to-outlet distance and “line-of-sight” for LV routing.
- It determines how much tunnel length/angulation is required for an intraventricular baffle.
- It predicts risk of iatrogenic LVOTO/RVOTO after repair. [1,3]
2) Anatomic Classification That Drives Physiology and Repair
A durable, clinically useful classification is based on VSD commitment to the subarterial outlets, because the outlet septum attachment governs which arterial valve the interventricular communication is “pointing toward.” [2]
2.1 Subaortic VSD (aorta-committed)
Anatomy
- The VSD lies beneath/adjacent to the aortic valve (aorta-facing outlet). [2]
Physiologic tendency
- Often behaves like TOF physiology when RVOTO/PS is present; otherwise it may resemble large VSD physiology with pulmonary overcirculation. [1]
Repair logic (conceptual)
- Favorable candidates for biventricular repair via LV-to-aorta intraventricular routing, with RVOT management dictated by the presence/degree of RVOTO. [1,4]
2.2 Subpulmonary VSD (Taussig–Bing spectrum)
Anatomy
- The VSD is committed to the pulmonary valve, frequently with an aorta that is anterior/rightward or side-by-side relative to the pulmonary artery. [2]
Physiologic tendency
- Frequently behaves like TGA-type streaming physiology (systemic desaturation with effective ventriculo–arterial discordance in flow pathways). [1]
Repair logic (conceptual)
- Often requires strategies that restore LV→aorta physiology, frequently incorporating arterial switch–type physiology restoration plus VSD management (specific approach is anatomy-dependent). [4,6]
2.3 Doubly committed (subarterial) VSD
Anatomy
- The VSD is related to both semilunar valves, typically reflecting deficiency/absence of the infundibular septum, placing both arterial valves at a similar level. [2]
Physiologic tendency
- Variable; highly sensitive to great artery relationship and the presence of outflow tract obstruction. [1]
Repair logic (conceptual)
- Planning prioritizes the least obstructive, most direct pathway to avoid baffle-induced LVOTO while preserving RVOT geometry. [1,2]
2.4 Noncommitted (remote) VSD
Anatomy
- The VSD is distant from both arterial valves, without direct alignment to either outlet. [2]
Why this subgroup is high-stakes
- Remote VSD is a classic “geometry problem”: longer/more angulated tunnels increase risk of late subaortic obstruction and reintervention, and AV valve/chordal anatomy more often constrains routability. [1,7,8]
Outcome signal
- In one series of biventricular repair for DORV with noncommitted VSD, reoperation occurred in 35%, commonly for subaortic stenosis, underscoring that the subaortic region is a frequent late failure point in this anatomy. [7]
3) Essential Modifiers (Because VSD Position Alone Is Not Enough)
VSD commitment frames the problem; the following modifiers usually decide the solution:
- Great artery relationship (anteroposterior vs side-by-side; degree/direction of override) [1,5]
- Conal/outlet septum anatomy (presence, malalignment, and its attachments) [2,3]
- AV valve and chordal constraints (straddling/overriding, chordae crossing potential tunnel paths) [1,5]
- Ventricular adequacy (balanced vs hypoplastic ventricle; feasibility of BiV vs SV pathway) [5]
- Outflow tract obstruction (baseline LVOTO/RVOTO and risk of iatrogenic obstruction after routing) [1,8]
- Coronary and arch anatomy (especially relevant when switch- or root-based strategies are considered) [5,8]
Large institutional experiences reinforce that anatomic subtype + these modifiers predict both the end-state (BiV vs SV palliation) and the risk of reintervention/mortality, supporting a geometry-first approach rather than a label-first approach. [5,8]
4) Imaging and Contemporary Planning (What Has Meaningfully Changed)
DORV surgery is increasingly planned as a 3D geometric reconstruction problem rather than a purely segmental diagnosis problem.
Practical 3D workflow (typical escalation)
- 2D/3D echocardiography for VSD rims, AV valve chordae, dynamic obstruction, and valve relationships. [1]
- CT/MRI-based 3D datasets for spatial relationships (VSD ↔ arterial valves, outflow tracts, coronaries, arch anatomy), especially when routability is uncertain. [1]
- Virtual reconstruction / 3D printing / VR for difficult cases (remote VSD, complex conal anatomy, or AV-valve constraints), where conventional imaging may not reliably predict whether a safe tunnel can be built without creating LVOTO/RVOTO. [9–11]
Evidence signal (planning accuracy)
- Studies using 3D virtual reconstruction and patient-specific physical models report improved understanding of VSD–valve–great artery relationships and better assessment of outflow obstruction risk, supporting their role when the BiV/SV decision is ambiguous. [9–11]
5) Outcomes Lens (Why classification is not academic)
Historical and contemporary surgical series show that DORV outcomes are strong when anatomy is favorable and strategy is matched to geometry, but complex DORV carries a distinct risk profile:
- A classic large series reported 10-year survival ~81% and freedom from reoperation ~65%, with higher early mortality in complex patients undergoing BiV repair and comparatively lower early mortality in complex patients undergoing Fontan-type pathways—highlighting that the “best” repair is the one that the anatomy can sustain long-term. [4]
- Modern BiV cohorts confirm that noncommitted/remote VSD anatomy is associated with higher late reoperation and mortality signals, reflecting the burden of long tunnels, restrictive VSD physiology, and concomitant lesion complexity. [8]
Take-home (High-yield summary)
DORV is a conotruncal, geometry-driven spectrum in which the VSD functions as the LV outlet. The most useful anatomic classification is therefore VSD commitment (subaortic, subpulmonary/Taussig–Bing, doubly committed, noncommitted/remote), but final strategy is governed by essential modifiers—especially conal/outlet septum anatomy, great artery relationship, AV valve/chordal constraints, ventricular adequacy, and obstruction risk. Contemporary best practice increasingly uses 3D imaging/virtual planning to predict routability and to minimize post-repair LVOTO/RVOTO, particularly in remote VSD and complex anatomy. [1–5,8–11]
References
[1] Goo HW. Double Outlet Right Ventricle: In-Depth Anatomic Review Using Three-Dimensional Cardiac CT Data. Korean J Radiol. 2021;22(11):1894-1908.
[2] Bharucha T, Hlavacek AM, Spicer DE, Theocharis P, Anderson RH. How should we diagnose and differentiate hearts with double-outlet right ventricle? Cardiol Young. 2017;27(1):1-15.
[3] Josowitz R, Rogers LS. Double outlet right ventricle - the 50% rule has always been about the conus. Curr Opin Cardiol. 2024;39(4):348-355.
[4] Kleinert S, Sano T, Weintraub RG, Mee RBB, Karl TR, Wilkinson JL. Anatomic features and surgical strategies in double-outlet right ventricle. Circulation. 1997;96(4):1233-1239.
[5] Bradley TJ, Karamlou T, Kulik A, et al. Determinants of repair type, reintervention, and mortality in 393 children with double-outlet right ventricle. J Thorac Cardiovasc Surg. 2007;134(4):967-973.e6.
[6] Brown JW, Ruzmetov M, Okada Y, Vijay P, Turrentine MW. Surgical results in patients with double outlet right ventricle: a 20-year experience. Ann Thorac Surg. 2001;72(5):1630-1635.
[7] Belli E, Serraf A, Lacour-Gayet F, et al. Double-outlet right ventricle with non-committed ventricular septal defect. Eur J Cardiothorac Surg. 1999;15(6):747-752.
[8] Villemain O, Belli E, Ladouceur M, et al. Impact of anatomic characteristics and initial biventricular surgical strategy on outcomes in various forms of double-outlet right ventricle. J Thorac Cardiovasc Surg. 2016;152(3):698-706.
[9] Ponchant K, Nguyen D, et al. Three-dimensional printing and virtual reconstruction in surgical planning of double-outlet right ventricle repair. JTCVS Open. 2022;13:197-208.
[10] Brüning J, Kramer P, Goubergrits L, et al. 3D modeling and printing for complex biventricular repair of double outlet right ventricle. Front Cardiovasc Med. 2022;9:1024053.
[11] Milano EG, Kostolny M, Pajaziti E, et al. Enhanced 3D visualization for planning biventricular repair of double outlet right ventricle: a pilot study on the advantages of virtual reality. Eur Heart J Digit Health. 2021;2(4):667-675.