A Brief History of HLHS Procedures

I had the chance to sit down with Dr. Frank Cetta, a pediatric cardiologist here at Mayo Clinic. He has been working at Mayo Clinic since 2003 and specializes in congenital heart disease. We discussed some of the history of congenital heart surgery and how we got to where we are today. This is the first post in a series of interviews with Dr. Cetta.

Stephen: We often talk about the “advent of modern surgical techniques” that have allowed hypoplastic left heart syndrome (HLHS) patients to thrive today. Could you tell me a bit about how we got here?

Frank: Sure. We have been able to manage progressively more complex congenital heart disease starting from about the early 1940s. The first major breakthrough we saw was in a patient with a different form of congenital heart disease in 1944 with the Blalock-Thomas-Taussig (BTT) shunt. This shunt helped increase blood flow to the lungs. There is actually an HBO movie, titled Something the Lord Made, on the monumental contribution to this technique of an African American laboratory technician named Vivien Thomas who has only recently begun to receive credit for his work. These days we still do some BTT shunts with some minor variations within the first HLHS staged surgery, the Norwood Procedure.

Then Dr. William Glenn in 1958 described his classic Glenn surgery – an early variation of the second staged single ventricle surgery.  This first procedure was later improved upon by Dr. Azzolina in 1973 and became the Bidirectional Glenn procedure that we still use today.

And lastly the Fontan procedure was developed by Dr. Francois Marie Fontan in 1971 with some further improvements to the procedure in the 80s and 90s.

Stephen: Why do we do these procedures?

Frank: A typical human heart has 4 chambers – a left and right atrium and a left and right ventricle. The atria act as holding chambers for blood, while the two ventricles pump blood – the left pumps blood to the body, and the right pumps blood to the lungs.

Since the left ventricle in a 4 chambered heart pumps blood out to the body, and the left ventricle is non-functioning in those with HLHS, we need a way to pump blood to the body. The Norwood procedure enables a single ventricle pump system to accomplish this by rerouting some of the blood from the right ventricle to the body.

Now imagine all of the extra blood that the single ventricle must pump. This extra blood can cause something called “Volume Overload”, which we want to avoid. This is one of the main reasons we do the second and third surgeries – to reroute half of that blood to the lungs.

Stephen: You mentioned that a typical heart pumps blood into the lungs. In a single ventricle heart, there is no pump for blood to the lungs. How does this work?

Frank: Because of the anatomical changes to the heart made by these surgeries, breathing actually helps a lot with this. When we take a breath in, the pressure in our head, neck, and abdomen is higher than in our chest. This is called “negative intrathoracic pressure”.  This negative pressure pulls blood from your body into your chest.

Stephen: With all of the recent advances in surgical techniques, have outlooks improved for patients with HLHS?

Frank: Yes – in a big way. Our numbers have shown considerably higher rates of success for those who have had their surgeries in more recent times.

To find out more on this topic, check out Dr. Cetta’s paper on a review of over 1000 Fontan patients at the following link: http://www.onlinejacc.org/content/66/15/1700.abstract.