Revolutionary surgical advancements during the second half of the 20th century have allowed patients with congenital heart disease to survive into their fifth and sixth decades for the first time in history. Unfortunately, it is a success story for which the medical community was unprepared.
“Adult cardiology and congenital cardiology are actually quite distinct,” said C. Huie Lin, MD, PhD, adult congenital cardiologist at Houston Methodist DeBakey Heart & Vascular Center. “Adult congenital disease is a completely different type of physiology and almost a different language.” As a result, many patients continue to see their pediatric congenital cardiologists well into adulthood.
One important advance is catheter interventions is the Melody Transcatheter Pulmonary Valve. “In the past, some of my patients with lesions such as Tetralogy of Fallot may have required three or even four open heart surgeries during a lifetime. But transcathter valve technology has brought a completely new optimism to the conversation I can have with my patients,” Lin said.
An additional innovation at Houston Methodist is the recent ability to create a 3-D printing of a patient-specific, congenitally malformed adult heart. Modeling the diseased heart allows physicians to simulate the precise placement of a valve. “I think having the 3-D model will help tremendously with patients with Tetralogy of Fallot,” Lin said.
One such case involved a 27-year-old Tetralogy of Fallot patient who posed several medical dilemmas: she lived on the East Coast, was a Jehovah’s Witness who would not accept blood products, and her right ventricular outflow tract (RVOT) was too large for conventional transcatheter valve replacement.
Based on the patient’s CT scan, performed locally and sent to Houston Methodist Hospital, Lin and his team were able to take her dataset and print a 3-D model of her heart.
“We took this 3-D replica to the hybrid operating room at MITIE (Houston Methodist Institute & Education) and were able to simulate the surgery before we even met the patient in person,” Lin explained. “In this simulated procedure, we confirmed that conventional transcatheter valve deployment was not feasible. But, we were able to devise a novel strategy of modifying the patient’s RVOT to create a landing zone for the new valve. We then deployed this strategy, and the patient was able to leave the hospital just a few days later with a new valve without the use of the heart-lung machine or blood transfusion.
Funding and expertise for the cardiac printing was provided by William J. Doré Jr., philanthropist and owner of the 3-D Print Bureau of Texas, LLC.
Being able to simulate procedures in individuals prior to surgery is one of the directions that will drive the field of 3-D printing.