The Natural History of Cardiac and Pulmonary Function Decline in Patients With Duchenne Muscular Dystrophy

Abstract

Study Design Retrospective review of scoliosis progression, pulmonary and cardiac function in a series of patients with Duchenne Muscular Dystrophy (DMD). Objective To determine whether operative treatment of scoliosis decreases the rate of pulmonary function loss in patients with DMD. Summary of Background Data It is generally accepted that surgical intervention should be undertaken in DMD scoliosis once curve sizes reach 35 degrees to allow intervention before critical respiratory decline has occurred. There are conflicting reports, however, regarding the effect of scoliosis stabilization on the rate of pulmonary function decline when compared to non operative cohorts. Methods We reviewed spinal radiographs, echocardiograms, and spirometry, hospital, and operative records of all patients seen at our tertiary referral center from July 1, 1992 to June 1, 2007 Data was recorded to Microsoft Excel and analyzed with SAS and R statistical processing software. Results The percent predicted forced vital capacity (PPFVC) decreased 5% /year prior to operation. The mean PPFVC was 54% (sd=21%) prior to operation with a mean postoperative PPFVC of 43% (sd=14%). Surgical treatment was associated with a 12% decline in PPFVC independent of other treatment variables. PPFVC after operation declined at a rate of 1% per year and while this rate was lower, it was not significantly different than the rate of decline present prior to operation (p=0.18). Cardiac function as measured by left ventricular fractional shortening declined at a rate of 1%/year with most individuals exhibiting an LVFS rate of >30 prior to operation. Conclusion Operative treatment of scoliosis in DMD using the Luque Galveston method was associated with a reduction of FVC related to operation. The rate of pulmonary function decline after operation was not significantly reduced when compared to the rate of preoperative FVC decline.

Truncal fat distribution correlates with decreased vital capacity in Duchenne muscular dystrophy

“…However, there is relatively little data on predictors of lung function. Scoliosis represents a risk factor for worsening restriction, but it is not clear if surgery to correct it slows the rate of lung function decline . Previous research has suggested that oral corticosteroid treatment may slow the rate of lung function decline without an observed increase in BMI.…”

The lifetime risk of pneumonia in patients with neuromuscular scoliosis at a mean age of 21 years: The role of spinal deformity surgery

“…In our experience the most severe patients with NMS are not able to perform reliable tests with a spirometer because of poor cooperation. Furthermore, most of the lung function studies have been performed among Duchenne muscular dystrophy patients and these results should therefore not be generalized to all neuromuscular patients [7, 9–11, 13, 14]. …”

Report of MDA muscle disease symposium on newborn screening for Duchenne muscular dystrophy

“…By age 10–12, more than 70% of boys lose ambulation. Many patients require noninvasive ventilator support at night by age 15, with death any time after age 20 related to pneumonia or cardiomyopathy . The natural history of the disease is significantly changed with the use of glucocorticoids.…”