Factors related to the durability of a homograft monocusp valve inserted during repair of tetralogy of Fallot as based on the mid- to long-term outcomes.

OBJECTIVES: To maintain pulmonary valvar function subsequent to repair of tetralogy of Fallot, we have inserted a homograft monocusp when a transjunctional patch was required. In this study, we have evaluated the mid- to long-term outcomes, aiming to determine the durability of the homograft. METHODS: Among 218 repairs performed for tetralogy of Fallot between July, 1996, and June, 2005, we inserted homograft monocusps in 54 patients, 4 of whom had associated absent pulmonary valve syndrome, 3 had pulmonary valvar atresia, and 1 had an atrioventricular septal defect with common atrioventricular junction. The median body weight at surgery was 7.8 kilograms, with a range from 3.9 to 42 kilograms. The function of the monocusp valve was assessed by regular echocardiography, using the Kaplan-Meier method and the Cox regression model for statistical analyses. RESULTS: There were 2 early deaths (3.7%), associated with respiratory infection. No late deaths were observed during the follow-up, which ranged from 0.3 to 120 months, with a median of 64.3 months. Freedom from valvar dysfunction was 67.2 +/- 6.7% at 1 year, 37.1 +/- 7.3% at 3 years, 23.8 +/- 6.7% at 5 years, and 21.2 +/- 6.4% at 7 years. We needed to replace the valve in 1 patient during follow-up. We found that ABO blood group incompatibility, stenosis of the pulmonary arteries, and associated absent pulmonary valve syndrome all adversely affected the function of the monocusp. CONCLUSION: Our experiences show that insertion of a homograft monocusp can prevent pulmonary regurgitation in the early period after repair of tetralogy of Fallot, but the effects are limited in duration as degeneration progressed. We still need to determine whether this finding can improve the longer-term function of the right ventricle.

Contrast media of high and low molecular weights in the detection of recurrent herniated disks.

PURPOSE: Our goal was to compare contrast enhancement of recurrent herniated disk fragments and scar after intravenous injection of a new high-molecular-weight contrast medium, Gadomer 17 (gadomer), with that after injection of a low-molecular-weight contrast medium, (gadopentetate dimeglumine). METHODS: Recurrent herniated disks were modeled in dogs by placing a fragment of intervertebral disk cartilage in the epidural space at laminectomy. MR imaging was performed with one of the contrast media at 20 and 50 days and with the other medium at 22 and 52 days. The changes in signal intensity from baseline in the disk fragment and in the adjacent scar tissue was measured at 2, 22, and 45 minutes. Differences were tested for significance with a student t-test. RESULTS: At 50 days after surgery, signal intensity in the intervertebral disk fragment increased by an average of 0.52 at 2 minutes after injection of gadomer and by an average of 0.90 after injection of gadopentetate. For scar, the increases in signal intensity were 1.41 (gadomer) and 1.62 (gadopentetate). At 22 and 45 minutes after injection, the signal intensity change in the disk fragment continued to be significantly greater after gadopentetate than after gadomer injection. In comparison with the changes at 50 days, both scar and disk fragment tended to show greater signal intensity changes at 20 days. Signal intensity changes in the disk fragments were significantly less after gadomer than after gadopentetate. Signal intensity changes in scar were slightly less with gadomer than with gadopentetate. CONCLUSION: Greater contrast is achieved between scar and recurrent herniated disk with a higher-molecular-weight contrast medium than with one of lower molecular weight. The difference between the high- and low-molecular-weight contrast media increases with maturation of the scar tissue.