Late outcome of 132 Senning procedures after 20 years of follow-up

Background: Risk factors and rates of reoperation, arrhythmias, systemic right ventricular dysfunction (RVD), and late death after a Senning procedure were investigated.

Methods: One-hundred thirty-two patients underwent a Senning operation between 1977 and 2004 (105 simple and 27 complex transpositions of the great arteries). Mean follow-up time was 19.5 ± 6.6 years. Surviving patients were evaluated by transthoracic echocardiography and electrocardiography. Right ventricular function was assessed in 70 patients by isotopic ventriculography or magnetic resonance imaging.

Results: Operative and late mortality were 5.3% (7/132) and 9.6% (12/125), respectively. Nine patients were reoperated for left ventricular outflow tract obstruction or baffle stenosis. Survival rate was 91.5%, 91%, 89%, and 88% at 1, 5, 10, and 20 years, respectively. Probability of maintaining permanent sinus rhythm was 80%, 65%, 55%, and 44%. Twelve patients required pacemaker implantation. Probability of no supraventricular tachycardia, atrial flutter/fibrillation or ventricular tachycardia was 95.5%, 91.5%, 88%, and 75%, respectively. These parameters were similar for simple and complex transposition. Probability of right ventricular ejection fraction >40% was 100% at 5 and 10 years, and 98% at 20 years for simple transposition, and 100%, 92%, and 58% for complex transposition. This difference was statistically significant. Risk factors for RVD were complex transposition (p < 0.001), body weight (p = 0.008), no cardioplegia (p < 0.001), and tricuspid valve regurgitation (p = 0.004).

Conclusions: Senning procedure results in very good long-term survival out to 20 years. Both RVD and baffle stenosis were rare, but there was a concerning incidence of arrhythmia over time suggesting careful long-term surveillance.