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My personal journey with CHD sparked my interest in pursuing cardiovascular research

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Hoggard and Morris

Photo courtesy of Jason Hoggard (pictured with Dr. Shaine Morris)

As a scientist with a Ph.D. background, my experiences have varied markedly from my co-fellows. My doctorate studies at the University of Houston focused solely on the genomics of cardiac development and congenital heart disease. Interestingly, I was the first person to earn a doctorate studying their own genome. Prior to my doctorate studies, I completed my master’s in Biomedical Science at the Brody School of Medicine at East Carolina University. The decision to move to Houston was exclusively for cardiovascular research and the potential to join one of the world’s best congenital heart disease departments. I became a postdoctoral research fellow at Texas Children’s in Oct. 2020. 

My interest in congenital heart disease (CHD) precedes my time at the University of Houston and is quite personal to me as I am actually a CHD patient. I was born with tricuspid atresia, in which the tricuspid (right atrioventricular) valve does not form. This malformation does not allow deoxygenated blood returning from the body to pass down into the right ventricle for distribution to the lungs. Instead, the blood flows into the left atrium, through an atrial septal defect, where it mixes with freshly oxygenated blood. This affects oxygen supply to the rest of the body, as mixed blood continues to recirculate. Unfortunately, the flow of blood from the right atrium into the left atrium can result in left atrial enlargement, and in some cases, left ventricular failure, due to overfilling. This condition is treated in a palliative manner with a multi-stage surgical course. The ultimate goal is to separate the oxygenated blood from the deoxygenated blood and to volume unload the left ventricle; the result of these procedures is a Fontan circulation in which blood returning from the body is routed directly to the pulmonary artery for delivery to the lungs.

My experiences as a CHD patient provided me with firsthand knowledge of what the single ventricle patients go through during childhood and into adulthood, which increased my drive and motivation to get involved in CHD research. My overall career goal is to give back to society through research findings that can be translated to improved clinical and surgical care, making the lives of patients in the future better than it is now.

Joining the division of Congenital Heart Surgery at Texas Children’s Hospital – the No.1 children’s hospital for pediatric cardiology and congenital heart surgery in the nation – is one of my greatest and proudest achievements. Fortunately, I already had a very strong working relationship with Dr. Shaine Morris in Cardiology, as she assisted with my training and research during my doctorate studies. However, as a Ph.D. in the clinical world for the first time, it was quite challenging to adapt to, yet incredibly worthwhile. During my fellowship, I gained invaluable experience that I know I cannot get anywhere else in the world. This position has also allowed me to expand my knowledge outside of purely cardiac development and into cardiovascular surgery as a whole. While I already had appreciation for what everyone in Congenital Heart Surgery does day-in and day-out, this opportunity has exposed me to an entirely new side that I never had the privilege to see as a patient.

My research in the Division of Congenital Heart Surgery has been focused on single ventricle forms of CHD. I brought a study that was a carryover from my doctorate work with me. This study sought to identify genomic associations, and clinical and surgical outcomes, in tricuspid atresia patients. I have made very exciting progress on the genomic side so far, identifying what appears to be a single development pathway that is disrupted via genetic mutations or chromosomal abnormalities in almost all documented non-syndromic tricuspid atresia patients within my study and in the current literature.

Additionally, I had the privilege of writing a case series on two families who each had two children with pulmonary vein stenosis and Cri du Chat syndrome; those two conditions have not been documented together prior to this point. Pulmonary vein stenosis is a condition in which the veins returning from the lungs, carrying oxygenated blood, are narrow or obstructed. This is a very difficult condition to treat, however, we have the best team of surgeons in the country for managing it. Cri du Chat syndrome is the result of missing part, or all, of chromosome 5; It is associated with a wide array of congenital abnormalities, not just cardiac. Interestingly, upon writing this review, it was realized that three individuals within the study also have bicuspid aortic valves and Cri du Chat syndrome. This is also a condition that has not been documented previously with Cri du Chat syndrome. Bicuspid aortic valve is a condition in which the valve allowing the passage of blood from the left ventricle into the aorta is improperly formed, having only two leaflets instead of three.

In addition to those studies, I have also begun working with Dr. Heather Dickerson (Cardiology) and Dr. Jeff Heinle (Congenital Heart Surgery) to create a center-wide database of all Texas Children’s Hospital heterotaxy syndrome patients. Heterotaxy syndrome has been an interest of mine, due to its complex nature, for several years; it has been an absolute pleasure to work with both physicians so far on this project. Dr. Dickerson has already completed substantial work over the years creating a dataset of existing heterotaxy patients, which may serve as the foundation for this database. The collective goal is to develop a database that can assist clinical and surgical care of heterotaxy syndrome patients. Additionally, we aim for it also to aid the surgeons and cardiologists when informing patients and their families of the expectations in the short-term and the long-term.

Through the generous support from the Spurlock family, and Augie’s Heart Tribe, I have been able to further develop myself into a more well-rounded scientist with clinical experience at the No. 1 place for pediatric cardiology and congenital heart surgery among children’s hospitals in the country. This is an experience that will be invaluable for the remainder of my career. The financial support has allowed additional meaningful and impactful research to be conducted that very well may improve the lives of patients with complex forms of congenital heart disease, such as children with heterotaxy syndrome and single ventricle patients.

External Author
Jason A. Hoggard, MSc, PhD., Postdoctoral Research Fellow, Division of Congenital Heart Surgery