Clinical Cases

When the heart tubes failed, plumbing helped

By

Dr. Sajan Koshy

Dr. Lincoln Samuel

Ms. Indhu S

Published on :

INTRODUCTION

Significant right ventricular outflow tract obstruction ending in palliative surgeries is a thing of the past. Over the last decade surgeons have improved highly effective reproducible techniques in creating conduits on the operating room table. These allow competent, durable reconstruction of right ventricular outflow with almost no chance of failure. We present the case of one such child born with complex congenital heart disease in whom a simple hand sewn conduit made a dramatic difference.

CASE REPORT

Master Sanand K A, 3-year-old boy, with genetic syndrome (Di George) presented with defects in multiple organ systems including congenital heart disease.

He was diagnosed to have double outlet right ventricle (DORV) with severe pulmonary stenosis (PS), on the 10th day of life. This comprises of a large ventricular septal defect (VSD) and severe obstruction to right ventricular outflow tract (RVOT).

The child had associated cleft palate and right sided hydrocele with un-descended testis. At 3 months of age, hernia repair with correction of un-descended testis was done.

At the age of 6 months, he was admitted with severe fall in oxygen saturation and increased work of breathing. He underwent a right Blalock-Taussig Shunt during this admission, following which oxygen saturation improved. The child had history of recurrent hospitalizations for aspiration pneumonia associated with cleft palate and poor oral intake. In 2017, he underwent percutaneous endoscopic gastrostomy for feeding to prevent aspiration.

The child was on regular follow up and showed signs of failure to thrive. Echo cardiogram showed feasibility of a bi-ventricular repair. Also the pulmonary valve and proximal main pulmonary artery was found to be dysplastic. In this situation we found a conduit repair to be advantageous over a standard RVOT repair.

Redo median sternotomy was done and adhesions were liberated. The heart was connected to cardio- pulmonary bypass by means of aortic and bi-caval cannulation. The body was cooled to 30 degrees Celsius; and the heart was arrested using a cold crystal- line cardioplegic solution. The right atrium was opened. The VSD margins were identified, and a poly-tetra-flouro- ethylene (PTFE) patch fashioned near to the shape of the defect was sewn to its edges by continuous prolene sutures closing the defect. The dysplastic pulmonary orifice was closed using a continuous prolene purse string suture. An incision was made on the anterior wall of the right ventricle just below its outflow.

Conduit Creation: While the above steps were undertaken, a hand-sewn conduit was prepared by the assistant in a sterile table set aside. A modified version of the procedure as described originally by Kruetzer and colleagues were followed [4].

The size of the PTFE tube is determined by the pulmonary diameter calculated according to body surface area of the child. In this case an 18 mm PTFE tube was selected [Fig 1a]. To create the valve a 0.1mm pericardial membrane was used. This was wrapped along the diameter of the tube to fix its length. Graft diameter multiplied by .75 is the height of the leaflet. The membrane was folded on its self three times to create a rectangle[Fig 1b]. This was cut sparing the future valve comissures and shaped similar to the normal pulmonary valve[Fig 1c]. When unfolded the leaflets could be seen as intended. The PTFE tube was turned inside out and the newly shaped pericardial membrane leaflets was sewn circumferentially at its distal part to create a trileaflet valve suing a continuous 8-0 prolene suture [Fig 2a]. The PTFE tube was re-inverted back [Fig 2b]. The conduit was tested and found to be competent.

The aortic cross clamp was released & the heart picked up in sinus rhythm. The conduit was sewn to the edges of the ventriculotomy proximally and to the edges of the pulmonary arteriotomy distally. After coming off bypass, TEE showed excellent flows to the branch pulmonary arteries via the conduit with good bi-ventricular function and trivial regurgitation in the hand sewn valve.

Post-operatively the child made good recovery. On follow up, echo-cardiography showed trivial pulmonary regurgitation with excellent flow across the conduit with no RVOT obstruction. Follow up at 3 and 6 months showed excellent function with trivial valve leak. The child became symptomatically better and gained weight. He is currently awaiting complete repair of his cleft palate.

Figures 4 - Completed conduit connected between
right ventricle and pulmonary artery.
Figures 4 - Completed conduit connected between right ventricle and pulmonary artery.

DISCUSSION

Hand sewn valves conduits have become popular over the last two decades for the treatment of children with RVOT obstruction with septatable ventricles. Initially, monoscup valves were used with moderate results1. Nunn et al pioneered the use of a bileaflet valve directly across the RVOT. In 2008 they published their results showcasing excellent durability with almost no valve failure2. These works paved the way for the even more durable valved conduits.

The bovine sourced xenograft conduit has been used to re-create RVOT in such children. It is associated with chance of re-stenosis, tube size limitations and difficulty in procurement at even tertiary Indian centers. Bovine membrane has also been used to create hand sewn valved conduit. However, biological conduits are associated with high chance of failure3.

More recently trileaflet valved PTFE conduits are being used owing to their durability, ease of reproducibility and economic advantage over other hand sewn valves. Zhang and colleagues at the Children’s Hospital of Fudan University, Shanghai, China, reported a series of 22 patients who underwent implantation of simplified PTFE hand sewn conduits versus 54 patients who received bovine conduits3. The first group was found to be associated with lower incidences of perioperative complication, graft failure, and early-phase mortality, as compared with conventional bovine grafts.

In our experience cost cutting is a very important factor. Most of the patients under our care have financial constraints. Use of expensive bovine conduits becomes impractical in this situation. This relatively novel techniques allows us to create highly durable valved conduit for less than half the cost.

References:

1. PTFE monocusp valve reconstruction of the right ventricular outflow tract; Mark W. Turrentine MD, Ryan P.McCarthy BS, PalaniswamyVijay MPH, PhD Kevin W.McConnell

BS, John W.Brown MD; Presented at the Thirty-sixth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 31–Feb 2, 2000.

2. Durability of hand-sewn valves in the right ventricular outlet; Graham R. Nunn MBBS (Hon), FRACS, A Ma Jayme Bennetts MB, BS, FRACS Ella Onikul MB, BS, FRACR; The Journal of Thoracic and Cardiovascular Surgery Volume 136, Issue 2, August 2008, Pages 290-297

3. Application of a Simplified Hand-Sewn Trileaflet Valved Conduit in Right Ventricular Outflow Tract Reconstruction as an Alternative for Bovine Jugular Vein Graft: Single- Center Experience; Zhang H, Ye, Yan X, Chen, Tao Q, Jia; Artif Organs. 2018 Jan;42(1):41-48. doi: 10.1111/aor.12968. Epub 2017 Oct 2.

4. The Autologous Pericardial Valved Conduit for Right Ventricular Outflow Tract Reconstruction; Christian Kreutzer, Christian Blunda, Guillermo Kreutzer, and Andres J. Schlichter; Operative Techniques in Thoracic and Cardiovascular Surgery, Vol 8, No 3 (August), 2003: pp 146-149

Aster Medical Journal
www.theamj.org