What are the causes of tricuspid regurgitation in patients with a history of heart disease, pulmonary hypertension, or right ventricular dysfunction?

Causes of Tricuspid Regurgitation

Tricuspid regurgitation is most commonly secondary (functional) rather than primary, caused by right ventricular and tricuspid annular dilation from left-sided heart disease, pulmonary hypertension, or right ventricular dysfunction—not from intrinsic valve pathology. 1

Secondary (Functional) Tricuspid Regurgitation

Secondary TR accounts for approximately 80% of all significant tricuspid regurgitation cases and occurs with structurally normal valve leaflets. 2

Mechanism of Secondary TR

The pathophysiology involves a progressive cascade: 1, 3

• RV pressure and/or volume overload leads to RV cavity enlargement
• Tricuspid annular dilatation occurs as the annulus loses its normal saddle shape, becoming flat, planar, and distorted—this is the most important factor in TR development 1, 3
• Papillary muscle displacement and leaflet tethering prevent proper coaptation 1, 3
• Self-perpetuating cycle: TR itself causes further RV dilation and dysfunction, leading to more annular dilatation and worsening TR 1, 3

Specific Causes of Secondary TR

Left-sided heart valve disease (most common cause): 1

• Mitral valve disease (particularly rheumatic) 1, 4
• Aortic valve disease 1
• Ischemic mitral regurgitation 4

Pulmonary hypertension: 1, 3

• Systolic PA pressures exceeding 55 mmHg cause TR even with anatomically normal tricuspid valves 2, 3
• Can result from left-sided heart disease, cor pulmonale, or idiopathic pulmonary artery hypertension 1
• Obesity-related mechanisms (obstructive sleep apnea, obesity hypoventilation syndrome) lead to pulmonary hypertension 2

Right ventricular dysfunction: 1, 5

• Intrinsic RV disease 1
• RV ischemia (hibernating right ventricle—an often overlooked reversible cause) 6
• Cardiomyopathy 1

Atrial fibrillation with annular dilatation: 7, 6, 8

• AF-induced annular remodeling is a major determinant of secondary TR 7

Congenital heart defects: 1

• Atrial septal defects causing RV volume overload 1

Obesity-related mechanisms: 2

• Increased plasma volume and cardiac output creating RV volume overload 2
• Cardiac autonomic neuropathy increasing dysrhythmia risk 2

Primary (Organic) Tricuspid Regurgitation

Primary TR results from structural abnormalities of the tricuspid valve apparatus itself. 1, 7

Specific Causes of Primary TR

Infective endocarditis: 1

• Especially in intravenous drug users 1
• Can involve vegetations on valve leaflets 1

Rheumatic heart disease: 1

• Causes leaflet retraction 1
• Almost always associated with left-sided valve lesions 1

Degenerative/myxomatous disease: 1

• Leaflet prolapse or flail 1, 8

Congenital abnormalities: 1

• Ebstein's anomaly 1
• Congenitally dysplastic valves 1

Carcinoid syndrome: 1

• Causes leaflet thickening and retraction 1

Endomyocardial fibrosis: 1

Drug-induced valve disease: 1

Iatrogenic causes: 1

• Thoracic trauma 1
• Pacemaker/ICD lead-related damage 1
• Post-surgical valve damage 1

Chordal rupture: 7

Critical Clinical Distinction

TR with systolic PA pressures below 40 mmHg typically reflects structural valve abnormalities (primary TR), whereas TR with systolic PA pressures exceeding 55 mmHg is likely functional even with anatomically normal valves. 3 This distinction is crucial for determining appropriate management strategies, as primary TR may require earlier surgical intervention while secondary TR management focuses on treating the underlying cause. 1, 7