How is coronary artery disease managed in patients with Duchenne muscular dystrophy (DMD)?

Cardiac Management in Duchenne Muscular Dystrophy (DMD)

Patients with Duchenne muscular dystrophy require comprehensive cardiac evaluation starting at diagnosis and regular monitoring throughout life, as cardiomyopathy is a leading cause of mortality in this population. 1

Initial Cardiac Assessment

• All DMD patients should undergo initial cardiac evaluation at diagnosis including physical examination, ECG, and imaging (echocardiography) regardless of symptoms (Class I; Level of Evidence B) 1
• Cardiac MRI with late gadolinium enhancement is preferred when available as it provides superior information on tissue characteristics, chamber dimensions, and function, particularly in patients with poor acoustic windows 2, 1
• Characteristic ECG findings in DMD include short PR interval, right ventricular hypertrophy, prolonged QT interval, and prominent Q waves in leads I, aVL, V5, and V6 or in leads II, III, aVF, V5, and V6 1
• NT-proBNP measurement should be added to echocardiography in routine cardiac assessment of DMD patients as it correlates with left ventricular dysfunction 3

Monitoring Schedule

• Asymptomatic DMD patients <10 years: cardiac evaluation every 2 years (Class IIa; Level of Evidence B) 1
• Asymptomatic DMD patients ≥10 years: annual cardiac evaluation (Class IIa; Level of Evidence B) 1
• DMD patients with LV dilation, dysfunction, or arrhythmia: at least annual evaluation (Class I; Level of Evidence C) 1
• Symptomatic DMD patients: more frequent evaluation than annually, with testing frequency determined by clinical status (Class I; Level of Evidence C) 1
• Ambulatory electrocardiographic monitoring every 1-3 years based on age, ejection fraction, and clinical assessment (Class IIa; Level of Evidence C) 1

Pharmacological Management

• ACE inhibitors or ARBs should be initiated as first-line therapy for cardioprotection in DMD patients, even with preserved left ventricular function 2, 1
• Consider adding eplerenone (aldosterone antagonist) to ACE inhibitor/ARB therapy in patients with early cardiomyopathy to slow the decline in left ventricular function 2, 4
• Beta-blocker therapy should be added after initiation of ACE inhibitor/ARB therapy, particularly in patients with ventricular dysfunction or elevated heart rate 2, 4

Advanced Cardiac Management

• For DMD patients with LVEF <35%, consider ICD placement following adult heart failure guidelines, weighing benefits against increased risks due to kyphoscoliosis and respiratory muscle weakness 2, 4
• Mechanical circulatory support with ventricular assist devices may be considered in select cases of advanced DMD cardiomyopathy as bridge to transplantation or destination therapy 2, 4
• Regular assessment of respiratory function alongside cardiac evaluation is essential as respiratory and cardiac involvement often progress in parallel 2, 1

Special Considerations for Female DMD Carriers

• Female DMD carriers should undergo cardiac evaluation by examination, ECG, and imaging in the second to third decade of life, with follow-up evaluations every 3-5 years thereafter (Class I; Level of Evidence C) 1
• CMRI studies have shown high frequency (80%) of cardiac pathologies in female DMD carriers including myocardial mass reduction, regional myocardial thinning, and late gadolinium enhancement 5
• Female carriers may develop severe cardiomyopathy requiring advanced therapies including ICD placement 6

Perioperative Cardiac Management

• Cardiac evaluation should be performed before anesthesia or sedation in any DMD patient (Class I; Level of Evidence C) 1
• For patients with history or symptoms of cardiac involvement, cardiac evaluation should be performed within 3-6 months of the anesthesia/sedation event (Class I; Level of Evidence C) 1
• Patients at increased cardiac risk during surgery should have cardiac monitoring by an anesthesiologist experienced in DMD care, and procedures should take place in centers with appropriate intensive care facilities (Class I; Level of Evidence C) 1

Important Pitfalls to Avoid

• Do not rely solely on symptoms to guide management, as typical heart failure symptoms may be absent or masked by skeletal muscle weakness 2
• Normal ECG and echocardiography findings do not exclude cardiac complications in DMD patients 2
• Do not delay initiation of cardioprotective therapy (ACE inhibitors/ARBs) until symptoms develop or LV dysfunction is present, as early intervention may slow disease progression 1, 2
• The pattern of cardiac involvement in DMD (inferolateral) may limit the effectiveness of certain interventions like cardiac resynchronization therapy 2