James E. Lock is Chairman of the Department of Cardiology at Children's Hospital and Professor of Pediatrics at Harvard Medical School. Lock attended medical school at Stanford University and pursued his pediatric residency and cardiology fellowship at the University of Minnesota. He then trained in cardiovascular physiology at the University of Toronto, Hospital for Sick Children. In 1980, Lock returned to Minnesota, where his research focused on experimental interventional cardiology. Most recently, he has pioneered nearly a dozen new procedures. In September of 1999, a device invented by Lock became the first septal occlussion device approved for use inside the human body in the United States.

During his research career, Lock has trained numerous academic physicians in cardiopulmonary physiology, and his innovations in experimental cardiology are internationally recognized. He has been elected to the Society for Pediatric Research and serves on the editorial boards of the professional journals Circulation, the American Journal of Cardiology and Cardiology.

2.14.01 Ankit Vachher asked:
If the fenestration saved Zach's life in the first place, then why is it necessary that the hole has to be closed? What could happen to Zach or Josh if the hole isn't closed?

Lock's response:
Immediately after open-heart surgery, our open-heart procedure produces a small but reversible amount of damage to the lungs and other organs. During the 3 to 10 days following open heart surgery, that damage makes it much harder for the circulation to get blood through the lungs and without a fenestration the patients can die from a low cardiac output state. However, in Zach's case that situation would have been made much worse by his viral infection. Once however, he recovers from the effect of open-heart surgery and recovers also from his viral infection, he now has a much better ability to pump all of the blood through his lungs. By closing the hole it forces all of the (deoxygenated, used-up) blue blood through his lungs and allows the rest of his body to be pink (fully oxygenated). If the hole isn't closed he remains with mild to moderate cyanosis for the rest of his life, and over the course of 10 to 20 years that blueness will produce damage to organs such as his heart and brain.

2.14.01 Mike Duncan asked:
How long will a stent last? Are they subject to clogging? Can they be cleared?

Lock's response:
Large stents like this in the pulmonary arteries seem to last a very long time. We put the first stent into a pulmonary artery exactly 23 years ago and that stent is still open without evidence of clogging. Clogging stents are usually seen in adults with coronary artery disease but almost never seen in the pulmonary arteries of children with congenital heart disease. Thus, we would expect it to last a lifetime.

2.14.01 Julie asked:
What is the success rate and the complications that have shown up to this point? Is it approved for just planned fenestrations or can it be used for other holes in the heart? Will there be an increase in the amount of blood thinners? Is the plug permanent or will it need to be replaced? What is the patch made of?

Lock's response:
The success rate depends on what we use it for. In closing fenestrations, the success is higher than 99% and there have been essentially no complications. In closing atrial septal defects, the newest devices have a success rate of higher than 98%. Occasionally we will see rare complications such as devices that were not positioned in the right location and falling out of the hole or transient periods of a fast heart rate or clots forming on the device. None of those complications have been fatal or produced a serious problem in any of more than 500 patients. For ventricular septal defects, a much more complicated form of disease, the success rate is between 90-95%. The complication rate is much higher but again it is not serious and it includes thing such as blood loss, arrhythmias or low blood pressure occurring during the procedure itself. All three of these complications are obviously much worse than what one might expect for open-heart surgery. The patient population with the worst results are adults who have had heart attacks and part of their heart muscle has died in between the two pumping chambers of the heart, producing an acute hole in the heart. The overall mortality for this event in adults is somewhere between 30-50% regardless of the form of therapy and we have really done only about 40 of those patients with improvements in survival but ongoing difficulties.

2.14.01 Cindy-Jean Dennis asked:
I have read a lot about you and think you do such amazing work! Dr. Lang is my son's cardiologist (at Children's Hospital) and Dr. Jonas is his surgeon. I read about some type of equipment that Dr. Jonas was working on. It measures the amount of oxygen to the brain during heart/lung machine surgeries. Is this approved or being used regularly yet? If not, is there an expected date?

Lock's response:
Dr. Jonas's research on oxygen supplied to the brain continues to work. Some of the devices he used were approved and are currently being used, and some of them are not yet approved and when they become available is a little bit unclear. However, Dr. Jonas and his colleagues are clearly at the very front of the field of protecting patients' brains during open heart surgery and remain committed to this most important aspect of managing patients.

2.14.01 Susan Hudson asked:
Do these children require anticoagulant therapy following this procedure?

Lock's response:
Children do not require formal anti-coagulation following this procedure. We usually put them on a single aspirin a day for six months and then stop altogether. In over 1,000 cases we have not had a significant clotting complication due to any of the devices

2.14.01 Clarice Parenti asked:
Why can my 5-year-old granddaughter withstand cold temperatures? While others in the house have multiple layers of clothing on & still feel cold, "Shana" has only a pair of pants on, feels cold to the touch, but will not keep any other clothes on. She had the Fontan in July 2000, just days before her 5th birthday; takes Lasix, Aldactone & aspirin daily; has a lot of energy & her color is excellent; she sleeps about 6 hours per night She had her 1st operation at 4 days old, the 2nd at 4 months. Is this a normal condition after the Fontan? Thank you for your time.

Lock's response:
Children with the Fontan procedure ordinarily have a reasonably normal circulation. I must tell you that if your granddaughter feels that cold temperatures are of no problem to her following the Fontan procedure, it is not something due to the Fontan but her own body metabolism. I am delighted to hear how well she is doing.