Time may heal a broken heart, but for infants born with life-threatening abnormalities of the heart's blood vessels, valves or chambers, the passing of time only makes matters worse.

The first successful experimental surgeries aimed at repairing heart defects in young children took place in the 1940s, and today heart surgery in children as young as a few weeks is a standard medical procedure to prevent a certain, early death. But open-heart surgery requires cutting through the breastbone and hour after hour of general anesthesia, not to mention mechanical ventilation via a heart-lung machine that keeps blood oxygenated and flowing throughout the body. Surgery also entails a painful recovery and the risk of infection. For small children, the experience can be especially traumatic.

Phillip Moore, a cardiologist and an associate professor of pediatrics at UCSF and the director of the Congenital Interventional Catheterization Program, hopes to change that traumatic series of interventions with a technique he first learned at Boston Children's Hospital. The technique obviates open-heart surgery by fixing the holes with patching devices deployed through a catheter.

"When I came back to UCSF," Moore says, "we became the first center on the West Coast to begin trialing these devices as they became available."

The defect that Moore most often repairs in this manner is called atrial septal defect, or ASD. In ASD a hole between the left and right atria causes oxygenated blood to be errantly routed back into the lungs, taxing both the heart and lungs. Children with ASD typically undergo surgery to prevent congestive heart failure, strokes or heart attacks in early adulthood.

The challenge of designing devices that will initially fit into a catheter but that later will take on a shape suitable for patching holes of a much larger diameter, has led to several imaginative inventions. The oldest design, improved and modified over the past three decades, is the "double umbrella," a metal frame supporting a polyester fabric. The frame collapses to fit inside the catheter, and once the device is in place, the umbrellas are opened to cover the hole from each side of the wall dividing the heart chambers. A much different-looking patch, marketed overseas, resembles a button, intended to be pulled tight against one side of the hole and then cinched. Another notable design now marketed in the US, which Moore uses and trains others to use, is a cylindrical wire mesh made of an aerospace alloy of nickel and titanium. The diameter of the cylinder abruptly flares out at two points along its length, forming patches that push up against each side of the hole. Pulled from either side, the mesh collapses, sort of like a Chinese finger trap, so that it fits into the catheter.

Moore began testing the double umbrella device in Boston, and continued testing it in two different phase 2 clinical trials after he returned to UCSF in 1994. In one trial, UCSF clinicians repaired ASDs in children as young as two. In a second trial, open only to adults and children for whom surgery would be especially risky due to other medical conditions, Moore and colleagues repaired not only ASDs, but also other holes in the heart, including a type known as a patent foramen ovule (PFO). These PFOs are not life threatening in children, but they are common, and are now suspected of causing thousands of strokes yearly in older adults by fostering the formation of blood clots that break away and lodge in blood vessels supplying the brain.

Once a patch is in the catheter, Moore inserts the thin plastic tube into a blood vessel in the groin and snakes it to the trouble spot in the heart. The patch is attached to a wire threaded through the catheter. Moore gently pushes the patch out of the catheter and, once it is in place over the hole, detaches it from the wire. Tissue quickly grows over the patch and helps keep it in place permanently. Recovery is rapid. Both children and adults go home the same day and resume full activity within a few days.

Moore says the rate of successful repair using patches is comparable to surgery, with fewer complications and lower costs. However, he adds, "it is still a foreign body that we are putting in the heart, and there can be complications." For instance, from 3 percent to 5 percent of adult patients develop abnormal heart rhythms because of the patch, he says.

Moore approached a medical device company, proposing to sew heart holes closed using a suturing device deployed through a catheter, a method that would eliminate the need for a patch. Such a device is already used to quickly stop bleeding during adult catheterization procedures, at the point where the catheter is removed from the blood vessel in the groin. Moore wants to use a catheter to send an even tinier sewing kit all the way up into the heart. He has found a willing company collaborator, and is now developing the new approach, using pigs as patients. Ultimately, he hopes to use this new method to suture shut a range of heart holes in both pediatric and adult patients.

See also:

UCSF Pediatric Cardiac Catherization Laboratory