Mechanical valves versus Ross procedure for aortic valve replacement in children: Propensity-adjusted comparison of long-term outcomes
Bahaaldin Alsoufi1, Cedric Manlhiot2, Brian McCrindle2, Mamdouh Al-Ahmadi1, Ahmed Sallehuddin1, Charles Canver1, Ziad Bulbul1, Mansoor Joufan1, Ghassan Siblini1, Zohair Al-Halees1, Bahaa Fadel1; 1King Faisal Heart Institute, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia; 2Hospital for Sick Children and University of Toronto, Toronto, ON, Canada
Comment on this Abstract
Objective: Aortic valve replacement (AVR) in children is problematic and all options are associated with major limitations. We compared outcomes in children who underwent AVR using mechanical prostheses versus pulmonary autografts (Ross procedure).
Methods: From 1983-2004, 346 children underwent AVR (215 Ross, 131 mechanical). Factors found to be associated with procedure choice (gender, age, pathology, hemodynamic manifestation, previous and concomitant surgeries) were used to construct a propensity score to adjust for non-randomization. Propensity-adjusted logistic and survival regression models were created to determine the effect of procedure type on operative mortality, long-term survival and cardiac reoperation.
Results: Patients undergoing Ross procedure were younger (p<0.01), more likely to have congenital etiology (p<0.01) or require annular enlargement (p<0.01). Patients undergoing mechanical AVR were more likely to have rheumatic or connective tissue etiology (p<0.01), aortic regurgitation (p<0.01), and concomitant cardiac surgery (p<0.01).
Unadjusted 1 and 10 year survival was stable at 98% for Ross vs. 94% and 83% for mechanical. Younger age was the most significant factor for operative (OR 1.3 per year, p<0.01) and late death (HR 1.2 per year, p<0.01) for mechanical valves but was neutralized as a risk factor for Ross.
Unadjusted 1 and 10 year freedom from aortic valve reoperation was 99% and 77% for Ross vs. 100% and 92% for mechanical.
After propensity-adjustment, mechanical valves were associated with greater odds of operative (OR 10.5, p=0.001) and late death (OR 9.3, p<0.01). Smaller mechanical sizes were associated with higher risk of death (RR 1.7 per mm, p=0.02) and valve reoperation (RR 1.8 per mm, p=0.001). Ross was associated with greater odds of aortic (OR 6.6, p<0.01) and cardiac reoperation (OR 3.0, p=0.03).
Although children with mechanical valves had more valve-related thromboembolic / bleeding complications, those events were too few to reach statistical significance. Adjusted comparison showed no significant difference in functional classification at last follow up with >99% of patients in NYHA functional class I (91%) or II (9%).
Conclusion: Analysis indicates excellent functional status and acceptable complication rate with both valve choices. Given significantly increased risk of early and late death in younger children receiving smaller mechanical valves, Ross procedure confers survival advantage in this age group at the expense of increased reoperation risk.
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