Damus–Kaye–Stansel Procedure #2: Side-to-End DKS Anastomosis

Date
May 19, 2026
URL
https://x.com/WithAScalpel/status/2056696121213264268?s=20
Categories
Cardiac Surgery

Damus–Kaye–Stansel Procedure #2: Side-to-End DKS Anastomosis

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The side-to-end Damus–Kaye–Stansel (DKS) anastomosis is a systemic outflow reconstruction used in patients with functional single-ventricle physiology who have established or anticipated systemic ventricular outflow tract obstruction (SVOTO). The technique connects the transected main pulmonary artery (MPA) to the lateral aspect of the ascending aorta, thereby allowing the pulmonary root to function as part of the systemic outflow pathway. This is the central concept shown in the original slide material: the DKS is not simply a vascular connection, but a method of creating a broader and less restrictive systemic outlet.

1. Surgical Concept

In many single-ventricle pathways, systemic outflow may depend on a restrictive bulboventricular foramen, subaortic outflow chamber, small VSD, or hypoplastic native aortic route. After volume unloading by bidirectional Glenn or later Fontan circulation, the ventricular geometry may change, and a previously mild narrowing can progress into clinically significant SVOTO.

The side-to-end DKS addresses this problem by redirecting systemic ventricular output through the pulmonary root and into the ascending aorta. Clinical series have shown that this approach can effectively eliminate the systemic outflow gradient and prevent late obstruction when performed at the appropriate stage of palliation [1, 2].

2. Technical Configuration

The operation consists of several key steps:

  1. Transection of the MPA proximal to the pulmonary artery bifurcation.
  2. Creation of an aortic opening on the lateral aspect of the ascending aorta.
  3. Side-to-end anastomosis between the proximal MPA and the ascending aorta.
  4. Flap or patch augmentation, when necessary, to avoid narrowing or distortion.

This configuration is particularly relevant when the great arteries are arranged in a side-by-side relationship, where a direct anastomosis may create tension, angulation, or asymmetric deformation. In such anatomy, an aortic flap or patch may be required to construct a wide, smooth, nonrestrictive pathway [3, 4].

3. Role of Flap or Patch Augmentation

Flap or patch augmentation should be considered when the native anatomy does not permit a tension-free, symmetric anastomosis. Important indications include:

  • Significant size discrepancy between the MPA and ascending aorta
  • Side-by-side great artery relationship
  • Limited mobility of the great vessels
  • Risk of anastomotic narrowing
  • Concern for pulmonary root or semilunar valve distortion

The goal is not only to create a large anastomotic orifice, but also to preserve the three-dimensional geometry of the pulmonary root. A technically wide anastomosis may still be suboptimal if it distorts the sinus, commissures, or valve leaflet coaptation.

4. Hemodynamic Benefit

The principal hemodynamic benefit of DKS is elimination or prevention of systemic outflow obstruction. In one series of patients undergoing DKS at the time of cavopulmonary connection, preoperative SVOT gradients were effectively abolished after DKS, supporting the strategy of addressing SVOTO risk before Fontan completion [1]. Similarly, prophylactic DKS performed with bidirectional Glenn has been reported as a useful strategy to maintain a nonobstructive systemic outflow pathway after Fontan circulation [2].

This is clinically important because residual or progressive SVOTO can increase systemic ventricular afterload, worsen ventricular hypertrophy, impair ventricular function, and contribute to atrioventricular valve regurgitation. In a Fontan candidate, even modest systemic outflow obstruction may have disproportionate long-term consequences.

5. Semilunar Valve Considerations

The major technical concern after side-to-end DKS is semilunar valve function, particularly pulmonary valve function after it becomes part of the systemic outflow pathway. Excessive traction, asymmetric anastomosis, twisting of the MPA stump, or distortion of the pulmonary sinus may impair leaflet coaptation and lead to late neoaortic regurgitation.

Several studies report low rates of recurrent SVOTO after DKS, but semilunar valve regurgitation remains an important surveillance target [3, 5]. Modified techniques, including aortic flap reconstruction, have been developed to reduce prosthetic material use, avoid root distortion, and preserve valve competence [4, 6].

6. Technique Selection: Side-to-End, Aortic Flap, and Double-Barrel DKS

The optimal DKS technique depends on the relationship of the great arteries and the geometry of the outflow tract.

  • Side-to-end DKS is useful when the transected MPA can be brought to the ascending aorta without excessive tension or distortion.
  • Aortic flap modification may be preferable when augmentation is required to create a broad anastomotic channel while preserving valve geometry [4, 6].
  • Double-barrel DKS may provide a more symmetric reconstruction in selected anterior-posterior great artery relationships and has been advocated by some authors to preserve pulmonary sinus configuration and valve function [3, 7].

Comparative data remain limited, but available series suggest that when the technique is tailored to the patient’s anatomy, recurrent SVOTO is uncommon across different DKS modifications [3].

7. Practical Surgical Principles

A durable side-to-end DKS depends on several operative principles:

  1. Create a generous systemic outflow pathway

    2. The aortic opening and MPA anastomosis must be large enough to avoid creating a new obstruction.

  2. Avoid tension and twisting

    3. The proximal MPA should reach the ascending aorta naturally. Tension may distort the pulmonary root or compromise the anastomosis.

  3. Preserve pulmonary root geometry

    4. The pulmonary valve becomes part of the systemic outlet; therefore, commissural alignment, sinus shape, and leaflet coaptation must be protected.

  4. Use augmentation when necessary

    5. Patch or flap reconstruction should be used proactively rather than accepting a narrow, angulated, or distorted connection.

  5. Evaluate both gradient and regurgitation

    6. Postoperative assessment should focus not only on relief of obstruction, but also on semilunar valve competence and ventricular performance.

8. Clinical Significance

The side-to-end DKS is most useful in single-ventricle patients with actual or anticipated SVOTO, particularly before completion of Fontan circulation. The operation can be performed as a therapeutic procedure for established obstruction or as a prophylactic procedure when anatomy suggests a high risk of future obstruction [1, 2, 8].

The broader clinical objective is to protect the systemic ventricle. By lowering outflow resistance, DKS may reduce afterload, preserve ventricular function, and support progression toward stable Fontan physiology. However, long-term success requires continued surveillance for neoaortic or pulmonary valve regurgitation, recurrent obstruction, coronary compression, and arch-related issues, especially in patients who undergo modified DKS in the neonatal or infant period [5, 8, 9].

Key Message

The side-to-end DKS anastomosis creates a nonrestrictive systemic outflow tract by connecting the transected MPA to the ascending aorta. Its value lies in reliable relief or prevention of SVOTO in single-ventricle pathways. The critical technical balance is to construct a wide anastomosis while preserving pulmonary root and semilunar valve geometry. Flap or patch augmentation should be used when needed to avoid narrowing, tension, or distortion.

References

[1] Alsoufi B, Al-Wadai A, Khan M, Al-Ahmadi M, Kalloghlian A, Bulbul Z, Al-Fayyadh M, Al-Halees Z. Outcomes of Damus-Kaye-Stansel anastomosis at time of cavopulmonary connection in single ventricle patients at risk of developing systemic ventricular outflow tract obstruction. Eur J Cardiothorac Surg. 2014;45(1):77-82. (PubMed)

[2] Shimada M, Hoashi T, Kagisaki K, Shiraishi I, Yagihara T, Ichikawa H. Clinical outcomes of prophylactic Damus-Kaye-Stansel anastomosis concomitant with bidirectional Glenn procedure. J Thorac Cardiovasc Surg. 2012;143(1):137-143.e1. (PubMed)

[3] Yang CK, Jang WS, Choi ES, Cho S, Choi K, Nam J, Kim WH. The clinical outcomes of Damus-Kaye-Stansel procedure according to surgical technique. Korean J Thorac Cardiovasc Surg. 2014;47(4):344-349. (PubMed)

[4] Masuda M, Tanoue Y, Ohno T, Tominaga R. Modified Damus-Kaye-Stansel procedure using aortic flap technique for systemic ventricular outflow tract obstruction in functionally univentricular heart. Eur J Cardiothorac Surg. 2006;29(6):1056-1058. (PubMed)

[5] Yamauchi S, Iwai S, Kawata H, Ozawa H, Kishimoto H. Risk factors for semilunar valve insufficiency after the Damus-Kaye-Stansel procedure. Ann Thorac Surg. 2015;100(5):1764-1770. (PubMed)

[6] Park CS, Lee CH, Kwak JG, Lee C. Modification of the Damus-Kaye-Stansel procedure. Ann Thorac Surg. 2010;90(4):1366-1368. (PubMed)

[7] Rosenblum J, Anvari F, Alsoufi B. The Damus-Kaye-Stansel operation: management of systemic ventricular outflow tract obstruction. Multimed Man Cardiothorac Surg. 2018;2018:mmx017. (PubMed)

[8] Huddleston CB, Canter CE, Spray TL. Damus-Kaye-Stansel with cavopulmonary connection for single ventricle and subaortic obstruction. Ann Thorac Surg. 1993;55(2):339-345. (PubMed)

[9] McElhinney DB, Reddy VM, Silverman NH, Hanley FL. Modified Damus-Kaye-Stansel procedure for single ventricle, subaortic stenosis, and arch obstruction in neonates and infants: midterm results and technique for avoiding circulatory arrest. J Thorac Cardiovasc Surg. 1997;114(5):718-726. (PubMed)

[10] Sarıtaş B, Özker E, Vuran C, Günaydın Ç, Türköz R, Ayabakan C. Treatment of subaortic stenosis in hearts with single-ventricle physiology. Cardiovasc J Afr. 2012;23(5):252-254. (PubMed)