Rerouting the Malformed Heart
Date: March 1, 2013
Pediatric cardiologist Phil Spevak and pediatric cardiac surgeon Luca Vricella sit transfixed, studying the myriad congenital abnormalities of the heart displayed on the screen before them. In a normal heart, blood from the lungs enters the left side of the heart; in this patient, it flows into the right side. Similarly, blood returning from the body enters the left side of this patient’s heart instead of the right side. On top of that, the patient was born with pulmonary atresia, a complete blockage of blood flow from the heart to the lungs. Then there’s the aorta branching off the right ventricle—not the ventricle designed to pump blood to the body. This patient’s cardiac anatomy is a roller-coaster of malformed coronary vessels and valves, explaining her cyanosis, chest pain and shortness of breath.
In terms of complex cases of congenital heart disease, “this one’s a 10,” says Vricella. “The question is,” adds Spevak, “is there a way to reroute the blood flow to end up with a physiology that’s close to normal?”
To do so, in the not-too-distant past surgeons had to rely on invasive imaging via cardiac catheterization or what they found in the OR.
But now, in the noninvasive imaging lab, they can manipulate 3-D MRI scans and plan procedures step by step. Not only can they investigate in detail the complete cardiac anatomy and vascular structures from all angles, but they can also measure flow velocities within them, which allows them to evaluate cardiac function and output.
These multiple views give the cardiac surgeon a precise picture of any septal defects, valvular problems and congenital malformations—and just how to correct them.
“The imaging stops Vricella from discovering any surprises while he’s operating, which generally means better outcomes,” explains Spevak.
“It’s not just the 3-D aspect, but the ability to look behind structures, and go from 3-D to 2-D and back, so if I want to locate that lung artery, there it is,” says Vricella. “The imaging gives you a virtual road map.”
Applying this road map in surgery, Vricella planned to reroute blood flow in the top chambers of the heart and create a synthetic baffle inside the aorta to channel blood to the right ventricle and then a conduit to continue the blood flow to the pulmonary artery and lungs to get the patient’s oxygen levels closer to normal.
Three-D MRI is especially beneficial for teens and young adults, adds Spevak, noting that the acoustic windows of echocardiography are limited in these patients. Indeed, this patient is in her late 30s and has undergone three operations since birth.
“Because of new imaging techniques,” says Spevak, “there may well be an operation for this patient that hadn’t been considered before.”