What are the next steps for a patient with a history of coronary artery disease (CAD) and recent coronary artery bypass grafting (CABG) who is experiencing fatigue in legs and shortness of breath?

Evaluation and Management of Post-CABG Fatigue and Dyspnea

This patient requires urgent evaluation for cardiac ischemia, heart failure, and graft failure, as these symptoms represent potentially life-threatening complications that demand immediate assessment and intervention. 1

Immediate Diagnostic Priorities

Assess for Acute Cardiac Ischemia

• Obtain 12-lead ECG immediately to evaluate for new ST-segment changes, pathological Q waves, or new left bundle branch block, as graft failure or acute MI can present with dyspnea rather than classic chest pain 1, 2
• Measure cardiac biomarkers (troponin), as elevation >99th percentile with symptoms suggests acute MI, which occurs in the vulnerable postoperative period 1, 2
• Consider urgent coronary angiography if biomarkers are elevated or ECG shows ischemic changes, as early graft failure requires immediate revascularization 2

Evaluate for Heart Failure

• Examine for jugular venous distention, third heart sound (S3), pulmonary rales, and peripheral edema, as these indicate volume overload requiring urgent diuretic therapy 3
• Measure brain natriuretic peptide (BNP) to quantify heart failure severity 3
• Obtain chest X-ray to assess for pulmonary edema and pleural effusions 3
• Check for mechanical complications including ventricular septal rupture or acute mitral regurgitation from papillary muscle dysfunction, which carry high mortality and may require emergent surgical intervention 3

Rule Out Arrhythmias

• Perform continuous cardiac monitoring, as ventricular tachycardia/fibrillation occurs in 5-10% of post-CABG patients, with 60% developing within 48 hours of symptom onset 1
• Assess for atrial fibrillation, which increases stroke risk and occurs commonly on postoperative day 2 4
• Evaluate electrolytes (potassium, magnesium) and correct abnormalities, as these contribute to arrhythmogenesis 1

Medication Review

Critical Assessment

• Verify beta-blocker compliance, as these should be prescribed to all post-CABG patients without contraindications and reduce mortality 1
• Review for NSAID use and discontinue immediately, as NSAIDs and COX-2 inhibitors increase cardiovascular events and mortality in post-CABG patients 3
• Assess metoprolol dosing, as shortness of breath and bradycardia occur in approximately 3% of patients on this medication 5

Consider Beta-Blocker Side Effects

• Metoprolol can cause dyspnea, wheezing (bronchospasm), tiredness, and peripheral arterial insufficiency in 1-3% of patients 5
• If beta-blocker intolerance is suspected, consider dose reduction or alternative agent rather than discontinuation, given mortality benefit 1, 5

Peripheral Vascular Assessment

Evaluate Lower Extremity Perfusion

• Examine for cold extremities, diminished pulses, and signs of arterial insufficiency, as metoprolol can worsen pre-existing peripheral circulatory disorders 5
• Concomitant peripheral vascular disease is common in CABG patients and affects outcomes 1
• Consider ankle-brachial index if claudication symptoms are present 5

Depression Screening

Screen for depression using validated tools, as it occurs in 33% of patients after CABG and is a more important predictor of cardiac rehabilitation success than functional cardiac variables 1

• Depression correlates with poorer physical functioning, quality of life, and predicts angina recurrence over 5 years 1
• Depressive symptoms can manifest as fatigue and reduced exercise tolerance 1
• Initiate cognitive behavioral therapy or telephone-delivered collaborative care if depression is identified, as these interventions improve quality of life, physical functioning, and likely reduce morbidity and mortality 1

Cardiac Rehabilitation Referral

Enroll patient in cardiac rehabilitation immediately if not already participating, as this is a Class I recommendation for all eligible post-CABG patients 1

• Formal programs beginning 4-8 weeks post-CABG with 3-times-weekly sessions for 3 months result in 35% increase in exercise tolerance 1, 6
• Participation reduces all-cause and cardiac mortality 1, 6
• Depression is a major barrier to rehabilitation success and must be addressed concurrently 1

Functional Capacity Testing

• Perform graded exercise treadmill testing to objectively measure exercise capacity and determine if symptoms are reproducible with exertion 6
• Assess for ischemic threshold if incomplete revascularization was performed 6
• Stress imaging (echocardiography or nuclear) is preferred over exercise ECG alone for detecting graft stenosis or restenosis 6
• Testing should evaluate clinical stability, hemodynamic response, rhythm disturbances, and degree of left ventricular impairment 6

Common Pitfalls to Avoid

• Do not attribute symptoms to "normal post-surgical recovery" without objective evaluation, as the postoperative period is a time of vulnerability for coronary events with significant impact on short- and long-term morbidity and mortality 2
• Never dismiss dyspnea as solely related to deconditioning without ruling out cardiac causes, as graft failure can occur early and requires urgent intervention 2
• Do not overlook depression, as it independently increases mortality risk (HR 2.4 for severe depression) and cardiac events (3-fold increase) 1
• Avoid continuing NSAIDs for pain management, as these are contraindicated and increase cardiovascular mortality 3