What could be the cause of shortness of breath in a patient with a history of venous insufficiency treated with radio frequency ablation (RFA), particularly in an athletic individual?

Differential Diagnosis of Exertional Dyspnea Following Radiofrequency Ablation for Venous Insufficiency

In an athletic patient with new-onset exertional dyspnea following radiofrequency ablation for venous insufficiency, the most critical immediate concern is pulmonary embolism from deep vein thrombosis, followed by cardiac causes including heart failure with preserved ejection fraction, pulmonary vascular disease, and exercise-induced bronchoconstriction. 1

Immediate Life-Threatening Causes to Exclude

Pulmonary Embolism and Deep Vein Thrombosis

• Pulmonary embolism must be the first consideration given the recent venous intervention and history of venous insufficiency, as these patients have documented risk for thromboembolic complications 1, 2
• Deep vein thrombosis occurs in approximately 1% of patients following radiofrequency ablation, with endovenous heat-induced thrombosis (EHIT) occurring in up to 15% of cases 2, 3
• The classic presentation includes dyspnea on exertion with reduced peak aerobic capacity, high ventilatory equivalent for CO2 (V̇E/V̇CO2 >34), increased dead space ventilation, and widened alveolar-arterial oxygen gradient 1
• Patients with pulmonary vascular disease demonstrate reduced peak VO2, low anaerobic threshold, and high V̇E/V̇CO2 ratio even during light physical activities 1

Cardiac Causes

• Heart failure with preserved ejection fraction (HFpEF) is a critical mimic that presents with exertional dyspnea in otherwise active individuals and must be distinguished from noncardiac causes 1
• The 2023 ACC guidelines emphasize that chronic venous insufficiency itself is listed as a noncardiac mimic of HFpEF, making this differential particularly challenging 1
• Cardiac dysfunction presents with reduced peak VO2, low O2 pulse, steeper heart rate-VO2 relationship, and early anaerobic threshold 1
• Women are at particular risk for underdiagnosis of cardiac causes when presenting with shortness of breath 4

Pulmonary Causes

Exercise-Induced Bronchoconstriction

• Exercise-induced bronchoconstriction should be considered in athletic individuals with exertional dyspnea, particularly when symptoms occur during vigorous exercise 1
• The diagnosis requires spirometry and detailed pulmonary examination to exclude underlying conditions such as COPD or restrictive lung disease 1
• Cardiopulmonary exercise testing with close observation is recommended to assess the clinical presentation and distinguish from other causes 1

Pulmonary Hypertension

• Pulmonary hypertension can masquerade as asthma with wheezing, chronic cough, and dyspnea on exertion 1
• These patients demonstrate peripheral airway obstruction, poor oxygenation, and early physiologic aerobic limits restricting exertion 1
• The condition presents with reduced peak VO2, low O2 pulse, high V̇E/V̇CO2, and increased dead space ventilation 1

Less Common but Important Considerations

Deconditioning

• Even in previously athletic individuals, physiologic limitation from deconditioning can cause exercise-induced dyspnea without bronchospasm or underlying disease 1
• This is perhaps the most common reason for exercise-induced dyspnea and presents with reduced peak aerobic capacity but normal ventilatory and gas exchange parameters 1

Hyperventilation and Anxiety Disorders

• Idiopathic hyperventilation with sustained hypocapnia and dyspneic drive should be considered, particularly in young women complaining of shortness of breath while running 1
• Psychological factors can obfuscate the diagnosis in patients with apparent exercise intolerance 1

Recommended Diagnostic Algorithm

Initial Assessment

• Measure vital signs including oxygen saturation, respiratory rate, pulse rate, blood pressure, and temperature immediately 4
• Perform focused cardiovascular examination checking for elevated jugular venous pressure, peripheral edema, and signs of right heart strain 4, 5
• Obtain ECG to assess for cardiac ischemia, arrhythmias, or right heart strain 4, 5

First-Line Investigations

• Order chest X-ray as the initial imaging study for all patients with unexplained shortness of breath 4
• Perform spirometry to assess for airflow obstruction and restrictive lung conditions 1, 4
• Obtain venous duplex ultrasound of bilateral lower extremities to exclude deep vein thrombosis and assess for EHIT 2, 3
• Consider D-dimer if pulmonary embolism is suspected, followed by CT angiography of the chest if indicated 4

Advanced Testing When Initial Workup is Unrevealing

• Cardiopulmonary exercise testing (CPET) is the definitive test to distinguish between cardiac, pulmonary, vascular, and deconditioning causes of exertional dyspnea 1
• Transthoracic echocardiography should be performed if cardiac cause is suspected, particularly to evaluate for HFpEF and pulmonary hypertension 1, 4
• Consider NT-proBNP measurement in conjunction with echocardiography for superior diagnostic accuracy of HFpEF 1

Critical Pitfalls to Avoid

• Do not assume the venous insufficiency treatment is unrelated to current symptoms—thromboembolic complications can occur weeks after radiofrequency ablation 2, 3
• Do not overlook cardiac causes in athletic individuals, as HFpEF can present with isolated exertional dyspnea in otherwise healthy-appearing patients 1
• Do not dismiss symptoms as deconditioning without objective testing, as serious cardiopulmonary pathology can present with subtle findings 1, 4
• Avoid administering high-concentration oxygen without arterial blood gas assessment if COPD or hypercapnic respiratory failure is possible 4
• Do not rely solely on resting pulmonary function tests or echocardiography, as these may be normal despite significant exercise limitation from pulmonary vascular disease or HFpEF 1