Outcomes of Mechanical Mitral Valve Replacement in Children

Abstract

Background: Mitral valve anomalies in children are rare but frequently severe, recalcitrant, and not often amenable to primary repair, necessitating mechanical mitral valve replacement (M-MVR). This study examined outcomes of a cohort undergoing a first M-MVR at age younger than 21 years.

Methods: We queried the Pediatric Cardiac Care Consortium, a multi-institutional United States-based cardiac intervention registry, for patients undergoing first M-MVR for 2-ventricle congenital heart disease. Survival and transplant status through 2014 were obtained from Pediatric Cardiac Care Consortium and linkage with the National Death Index and the Organ Procurement and Transplantation Network.

Results: We identified 441 patients (median age, 4.3 years; interquartile range, 1.3 to 10.1 years) meeting study criteria. The commonest disease necessitating M-MVR was atrioventricular canal (44.3%). Early mortality (death <90 days after M-MVR) was 11.1%; there was increased risk of early death if age at M-MVR was younger than 2 years (odds ratio, 7.8; 95% confidence interval [CI], 1.1 to 56.6) and with concurrent other mechanical valve placement (odds ratio, 8.5; 95% CI, 2.0 to 35.6). In those surviving more than 90 days after M-MVR, transplant-free survival was 76% at 20 years of follow-up (median follow-up, 16.6 years; interquartile range, 11.9 to 21.3 years). Adjusted analysis in those who survived more than 90 days showed elevated risk of death/transplant for boys (hazard ratio, 1.5; 95% CI, 1.0 to 2.3), age at M-MVR younger than 2 years (10-year survival: hazard ratio, 4.3; 95% CI, 1.2 to 15.1), and nonbileaflet prosthesis placement (hazard ratio, 2.4; 95% CI, 1.3 to 4.3).

Conclusions: M-MVR is a viable strategy in children with unrepairable mitral valve disease. Age younger than 2 years at the first M-MVR is associated with significant early risk of death and poorer long-term survival.

Figure 1:

Inclusion/Exclusion Criteria

Figure 2:

Age at 1^st-M-MVR among eligible children treated <21 years of age for congenital mitral valve abnormalities in the PCCC

Figure 3.

(a) Early mortality (≤90 days post-1^st M-MVR), late mortality/cardiac transplant (>90 days post-1^st M-MVR) and transplant free survivors by age at 1^st-M-MVR. (b) Proportional illustration representing the age of mortality / cardiac transplant in patients undergoing M-MVR. Within cohort percentages in each age group are depicted on Y axis. Early mortality / cardiac transplant is predominant in those < 2 years of age at 1^st M-MVR, late mortality / cardiac transplant is more evenly distributed across the age groups.

Figure 3.

(a) Early mortality (≤90 days post-1^st M-MVR), late mortality/cardiac transplant (>90 days post-1^st M-MVR) and transplant free survivors by age at 1^st-M-MVR. (b) Proportional illustration representing the age of mortality / cardiac transplant in patients undergoing M-MVR. Within cohort percentages in each age group are depicted on Y axis. Early mortality / cardiac transplant is predominant in those < 2 years of age at 1^st M-MVR, late mortality / cardiac transplant is more evenly distributed across the age groups.

Figure 4:

Overall transplant-free survival (including early and late mortality / cardiac transplant) after 1^st M-MVR

Figure 5.

(a) Transplant-free survival from 1^st cardiac surgery in patients with underlying CAVC compared between those receiving M-MVR before the age of 6 years and patients who did not require M-MVR (b) Hazard of death / cardiac transplant over time from 1^st cardiac surgery in patients < 6 years of age with underlying CAVC who had M-MVR compared to patients who did not require M-MVR.

Figure 5.

(a) Transplant-free survival from 1^st cardiac surgery in patients with underlying CAVC compared between those receiving M-MVR before the age of 6 years and patients who did not require M-MVR (b) Hazard of death / cardiac transplant over time from 1^st cardiac surgery in patients < 6 years of age with underlying CAVC who had M-MVR compared to patients who did not require M-MVR.