Damus–Kaye–Stansel Procedure #1: Concept of DKS Anastomosis

The Damus–Kaye–Stansel (DKS) anastomosis is a surgical reconstruction designed to establish a wide, unobstructed systemic ventricular outflow pathway in patients with functional single-ventricle physiology or complex ventriculoarterial anatomy. Its principal role is to relieve established systemic ventricular outflow tract obstruction (SVOTO) or to prevent its progression when the native systemic outlet is anatomically vulnerable [1, 2].

In practical terms, the operation incorporates the pulmonary root into the systemic arterial pathway by creating an anastomosis between the main pulmonary artery/pulmonary root and the ascending aorta. This converts the pulmonary root into part of the systemic outflow tract and allows systemic ventricular output to reach the aorta through a broader and less restrictive route.

1. Why SVOTO Matters in Single-Ventricle Physiology

In single-ventricle circulation, even a modest degree of systemic outflow obstruction can have major physiologic consequences. The systemic ventricle must support the entire cardiac output, and any obstruction between the ventricle and the aorta increases afterload.

Common anatomic substrates include:

1. Restrictive bulboventricular foramen

Often seen in double-inlet left ventricle or related single-ventricle variants.

2. Subaortic stenosis

May be present initially or may progress after staged palliation.

3. Hypoplastic native aortic outflow tract

Particularly important when the aorta arises from a small outlet chamber.

4. Arch obstruction combined with single-ventricle anatomy

In neonates and infants, systemic outflow obstruction may involve both the intracardiac outlet and the aortic arch [2].

If uncorrected, SVOTO can lead to ventricular hypertrophy, impaired diastolic filling, atrioventricular valve regurgitation, ventricular dysfunction, and poor candidacy for later Glenn or Fontan circulation.

2. Core Surgical Concept

The DKS procedure is based on a simple but powerful principle:

If the native aortic outlet is too narrow or at risk of becoming restrictive, the pulmonary root can be incorporated into the systemic outflow pathway to create a larger and more durable outlet.

This reconstruction allows blood ejected from the systemic ventricle to pass through the pulmonary root and into the ascending aorta. The procedure therefore bypasses or neutralizes the restrictive native systemic outlet.

The goal is not merely to create an anatomic connection between two great arteries. The goal is to create a low-resistance systemic outflow pathway that can remain stable throughout staged single-ventricle palliation.

3. Hemodynamic Objectives

The main hemodynamic objective of DKS is systemic ventricular decompression.

Key goals include:

• Relief of established SVOTO
• Prevention of future SVOTO after volume unloading
• Reduction of systemic ventricular pressure load
• Preservation of ventricular systolic and diastolic function
• Maintenance of atrioventricular valve competence
• Creation of a stable pathway toward Glenn and Fontan completion

This concept is especially important because SVOTO may become more evident after pulmonary artery banding or after cavopulmonary connection, when ventricular volume loading changes and the bulboventricular foramen or ventricular septal defect may become more restrictive [3, 4].

4. Timing of DKS: Therapeutic Versus Prophylactic Use

The DKS anastomosis can be performed either as a therapeutic operation for established obstruction or as a prophylactic strategy in patients at high risk for future obstruction.

A. Therapeutic DKS

Therapeutic DKS is performed when there is clear evidence of systemic outflow obstruction, such as:

• Significant ventricular-to-aortic gradient
• Progressive subaortic narrowing
• Restrictive bulboventricular foramen
• Ventricular hypertrophy or ventricular dysfunction related to outflow obstruction

In this setting, DKS functions as a rescue or corrective operation to remove a clinically relevant obstruction.

B. Prophylactic DKS

Prophylactic DKS is performed before severe obstruction develops. This strategy is particularly relevant in patients whose systemic outlet appears anatomically fragile, even if the measured gradient is not yet severe.

Several clinical series support the concept that DKS performed at the time of bidirectional Glenn or cavopulmonary connection can effectively prevent late SVOTO in selected single-ventricle patients [4, 5]. This is important because waiting for a high gradient may allow ventricular hypertrophy, atrioventricular valve regurgitation, or impaired Fontan candidacy to develop before intervention.

5. Surgical Configurations

Several technical variations of DKS have been described. The two most commonly discussed are the side-to-end and double-barrel configurations.

A. Side-to-End DKS Anastomosis

In the side-to-end configuration, the main pulmonary artery is divided and anastomosed to the side of the ascending aorta.

This technique creates a direct pathway from the pulmonary root to the aorta and can be useful when the great arteries require mobilization or when the pulmonary artery anatomy is more suitable for this orientation.

Potential concerns include distortion of the pulmonary root or semilunar valve geometry if the anastomosis is under tension or if the pulmonary sinus is deformed.

B. Double-Barrel DKS Anastomosis

In the double-barrel configuration, the adjacent pulmonary and aortic roots are joined side-by-side to create a broad common systemic outlet.

This approach preserves the relationship of the semilunar roots and may reduce distortion of the pulmonary valve and sinus. Comparative studies have suggested that the double-barrel technique may be favorable for preserving pulmonary valve function, although direct comparative evidence remains limited and patient anatomy strongly influences technique selection [6, 7].

6. Expected Outcomes

Overall, the DKS procedure has been reported to provide effective and durable relief of systemic ventricular outflow obstruction in single-ventricle patients.

Important outcome themes include:

1. Excellent relief of SVOTO

Series of DKS performed at the time of cavopulmonary connection have shown marked reduction or elimination of systemic outflow gradients, with low rates of recurrent obstruction [5].

2. Low DKS-related reintervention in many series

Earlier and contemporary studies report acceptable freedom from DKS-related reoperation when the anastomosis is technically adequate and semilunar valve function is preserved [1, 5].

3. Importance of semilunar valve preservation

Because the pulmonary root becomes part of the systemic outlet, postoperative pulmonary/neoaortic valve function is critical. Valve distortion, regurgitation, or root geometry problems can affect long-term outcomes [6, 7].

4. Potential advantage of earlier primary DKS in selected patients

More recent long-term data suggest that primary DKS without prior pulmonary artery banding may be associated with better survival, preserved ventricular function, and less neoaortic regurgitation compared with staged strategies after banding in selected functional single-ventricle patients [8].

7. Surgical Principles

The technical objective is to create the widest possible systemic outlet while preserving the geometry and function of adjacent structures.

Important operative principles include:

• Adequate mobilization of the great arteries
• Creation of a tension-free anastomosis
• Avoidance of semilunar valve distortion
• Preservation of coronary artery geometry
• Maintenance of unobstructed arch flow
• Avoidance of branch pulmonary artery distortion
• Integration with the planned source of pulmonary blood flow, such as a shunt, bidirectional Glenn, or Fontan pathway

The operation should be judged not only by the immediate appearance of the anastomosis, but also by whether the reconstruction provides a durable systemic outlet suitable for long-term single-ventricle palliation.

8. Practical Conceptual Summary

The DKS anastomosis is best understood as a systemic outflow reconstruction rather than simply a great-artery anastomosis.

By incorporating the pulmonary root into the aortic pathway, the surgeon creates a broad systemic outlet and protects the single ventricle from the adverse effects of obstruction. In the staged single-ventricle pathway, this is a central principle: before a patient can safely progress toward Glenn and Fontan circulation, the systemic ventricle must have a reliable, unobstructed route to the aorta.

A successful DKS therefore accomplishes three goals simultaneously:

1. It relieves or prevents SVOTO.
2. It protects systemic ventricular function.
3. It preserves the long-term feasibility of staged single-ventricle palliation.

References

[1] Gates RN, Laks H, Elami A, Drinkwater DC Jr, Pearl JM, George BL, et al. Damus-Stansel-Kaye procedure: current indications and results. Ann Thorac Surg. 1993;56(1):111-119.

[2] 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 techniques for avoiding circulatory arrest. J Thorac Cardiovasc Surg. 1997;114(5):718-725.

[3] Huddleston CB, Canter CE, Spray TL. Damus-Kaye-Stansel with cavopulmonary connection for single ventricle and subaortic obstruction. Ann Thorac Surg. 1993;55(2):339-346.

[4] 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.

[5] Alsoufi B, Al-Wadai A, Khan M, Al-Ahmadi M, Kalloghlian A, Bulbul Z, et al. 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.

[6] Fujii Y, Kasahara S, Kotani Y, Takagaki M, Arai S, Otsuki S, et al. Double-barrel Damus-Kaye-Stansel operation is better than end-to-side Damus-Kaye-Stansel operation for preserving the pulmonary valve function: the importance of preserving the shape of the pulmonary sinus. J Thorac Cardiovasc Surg. 2011;141(1):193-199.

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

[8] Kido T, Steringer-Mascherbauer R, Vodiskar J, Burri M, Ewert P, Strbad M, et al. Improved long-term outcome of Damus-Kaye-Stansel procedure without previous pulmonary artery banding. Ann Thorac Surg. 2022;114(2):545-551.