SESSION TITLE: Pediatic Pulmonary & Critical Care
SESSION TYPE: Original Investigation Slide
PRESENTED ON: Monday, October 27, 2014 at 04:30 PM - 05:30 PM
PURPOSE: Current care extends survival for some patients (pts) with Duchenne muscular dystrophy (DMD). We compare the clinical characteristics of pts with DMD and very prolonged survival (VPS) to pts with early death (ED), to identify potential risk factors.
METHODS: Retrospective cohort study of our pts with DMD from 1999-present. DMD diagnosed by clinical features and muscle biopsy and/or genetic testing. VPS was defined as alive and >/= 30 yrs old. Early death (ED) was defined as death at < 30 yrs old. Excluded: pts with steroid therapy.
RESULTS: Among the 70 pts with DMD who are alive, 12 pts have VPS (17%) and are at mean age +/- SD 33.9 +/- 4.3 yrs (range 30-44 yrs). 13 pts had early death (ED) at age 21.8 +/- 3.9 yrs (range 16-27 yrs) (p < .001 for age). All VPS pts are ventilated 24 hrs/day (duration of 24 hr/day ventilation: 9.6 +/- 5.6 yrs). Their vital capacity (VC) fell to < 1 liter 14.3 +/- 4.9 yrs ago and all VPS pts now have a VC of 0 mL. In contrast, last VC for the ED pts was 742 +/- 520 mL (n = 12). 9 of 12 ED pts (75%) have VC > 0 mL versus none of the VPS pts (p = .005). VC fell to < 1 liter at 20.1 +/- 4.4 yrs of age in the VPS pts and 18.8 +/- 3.6 yrs in the ED pts, with 4 of 13 ED pts having a last VC > 1 liter (31%). 5 of 11 VPS pts have a tracheostomy (45%) versus no ED pts. The ejection fraction (EF) for the VPS pts is 42.2 +/- 14.2% (n=11) versus a last EF for the ED pts of 30 +/- 14.4% (n=12; p=.052). Just 4 of the 11 VPS pts (36%) meet criteria for cardiomyopathy (DCM), while 10 of 13 ED pts met criteria for DCM (76%; p = 0.09). 7 of the 13 ED pts died from cardiac causes (54%).
CONCLUSIONS: VPS pts have unmeasurably low VCs. Their survival was enabled by 24 hr/day mechanical ventilation. In contrast, VPS patients have good heart function. Only 4 of 11 VPS pts have dilated cardiomyopathy (DCM), despite their advanced age and pulmonary impairment. ED pts had relatively better pulmonary function: 9 of 12 pts had a VC > 0 mL and 4 pts had a last VC > 1 liter. Despite their younger age and better pulmonary function, cardiac function was worse in the ED pts: 10 of 13 pts had DCM and 7 of 13 pts died from cardiac causes.
CLINICAL IMPLICATIONS: Heart function appears to be the main determinant of survival in pts with DMD, when assisted ventilation is used to compensate for loss of pulmonary function. When cardiac function is good, pts are more likely to achieve VPS. Most VPS pts have a cardiopulmonary phenotypic "disconnect": good heart function despite poor pulmonary function.
DISCLOSURE: David Birnkrant: Consultant fee, speaker bureau, advisory committee, etc.: Hill-Rom Corporation The following authors have nothing to disclose: Erhan Ararat, Maroun Mhanna
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