Carcinoid Heart Disease: Surgical Timing, Right Ventricular Risk Stratification and Operative Strategy

Figure 1. Pathophysiology of carcinoid heart disease. Vasoactive mediators released by hepatic neuroendocrine tumour metastases reach right-sided cardiac structures, inducing fibrous plaque deposition and progressive valve dysfunction. The optimal surgical window—before irreversible right ventricular dysfunction—is indicated. Serotonin (5-HT) acts via 5-HT2B receptors on valvular interstitial cells, stimulating mitogenesis and extracellular matrix (ECM) production through transforming growth factor-beta (TGF-β) signalling. Tachykinins and other vasoactive peptides contribute to the fibrotic process. The resulting fibrous plaques comprise myofibroblasts, smooth muscle cells, and collagen-rich ECM deposited preferentially on the downstream aspect of valve leaflets, causing retraction, immobility, and progressive regurgitation. Pulmonary vascular endothelium efficiently metabolises serotonin via monoamine oxidase (MAO), protecting left-sided structures except in the presence of patent foramen ovale (PFO) or bronchial carcinoid. The cascade from tricuspid regurgitation through right ventricular (RV) dilatation to irreversible RV failure and hepatorenal dysfunction defines the finite surgical…

Figure 2. Proposed algorithm for the timing of cardiac surgery in carcinoid heart disease. * RV function thresholds—FAC: fractional area change; TAPSE: tricuspid annular plane systolic excursion; RVEDA: RV end-diastolic area. TVR = tricuspid valve replacement; PVR = pulmonary valve replacement; MDT = multidisciplinary team; NT-proBNP = N-terminal pro-B-type natriuretic peptide. GRADE evidence quality for referral thresholds: Low to Very Low. Thresholds represent expert consensus, not prospectively validated CaHD-specific cutoffs. The algorithm integrates echocardiographic parameters, right ventricular function assessment, NT-proBNP trajectory, and oncological disease status. Entry point: all patients with carcinoid syndrome and elevated urinary 5-HIAA should undergo baseline echocardiographic screening. Decision nodes are based on TR severity (severe: VC > 7 mm or EROA > 40 mm2), RV systolic function (FAC ≥ 30% representing the optimal surgical window; FAC < 25% indicating elevated operative risk), TAPSE (≥16 mm acceptable; <14 mm advanced dysfunction), rising NT-proBNP trajectory, and oncological disease status (controlled or stable with life expectancy > 12 months). The algorithm…

Figure 3. Proposed operative strategy algorithm for carcinoid heart disease. Decision points for tricuspid and pulmonary valve intervention, prosthesis selection, and the role of transcatheter valve-in-valve therapy for degenerated bioprostheses are illustrated. The algorithm commences with the decision for tricuspid valve replacement (TVR), which is required in the vast majority of CaHD patients given that repair yields poor results due to leaflet fibrosis and retraction. Intraoperative transoesophageal echocardiography (TOE) is essential to confirm prosthesis function. A low threshold for concomitant pulmonary valve replacement (PVR) is advocated where concurrent pulmonary valve disease is present, as leaving significant disease uncorrected imposes persistent afterload on the compromised RV. Bioprosthetic valves are preferred on the basis of anticoagulation avoidance and the feasibility of subsequent transcatheter valve-in-valve therapy. For patients developing bioprosthetic structural valve degeneration, transcatheter valve-in-valve replacement provides a less invasive alternative to redo sternotomy, particularly in those with prohibitive surgical risk. Primary transcatheter TVR using…