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AIMS: Valvular surgery has improved long-term prognosis in severe carcinoid heart disease (CaHD). Experience is limited and uncertainty remains about predictors for survival and strategy regarding single vs. double-valve surgery. The aim was to review survival and echocardiographic findings after valvular surgery for CaHD at our institution.

METHODS AND RESULTS: Between 1986 and 2019, 60 consecutive patients, median age 64 years, underwent valve surgery for severe CaHD. Operations involved combined tricuspid valve replacement (TVR) and pulmonary valve replacement (PVR) in 42 cases, and TVR-only or TVR with pulmonary valvotomy (no PVR) in 18 patients. All implanted valves were bioprosthetic. Preoperative echocardiography, creatinine, NT-pro-brain natriuretic peptide (NT-pro-BNP), and 24-h urinary 5-hydroxyindoleacetic acid (5-HIAA) were obtained. 30-Day mortality was 12% (n=7), and 8% for the most recent decade 2010-2019. Median survival was 2.2 years and maximum survival 21 years. Patients undergoing combined TVR and PVR had significantly higher survival compared with operations without PVR (median 3.0 vs. 0.9 years, P = 0.02). Preoperative levels of NT-pro-BNP and 5-HIAA in the top quartile predicted poor survival. On preoperative echocardiograms, pulmonary regurgitation was severe in 51% and indeterminate in 17%. Postoperative echocardiography confirmed relatively good durability of bioprostheses, relative to the patients' limited oncological life expectancy.

CONCLUSION: Valvular surgery in CaHD has an acceptable perioperative risk. Survival for combined TVR and PVR was significantly higher compared with operations without PVR. Bioprosthetic valve replacement appears to have adequate durability. Preoperative echocardiography may underestimate pulmonary pathology. Combined TVR and PVR should be considered in most patients.

Subjects with asymptomatic moderate-severe or severe primary mitral regurgitation (MR) are closely observed for signs of progression or symptoms requiring surgical intervention. The role of myocardial metabolic function in progression of MR is poorly understood. We used ¹¹C-acetate positron emission tomography (PET) to non-invasively measure myocardial external efficiency (MEE), which is the energetic ratio of external cardiac work and left ventricular oxygen consumption.

Methods and Results: 47 patients in surveillance with MR and no or minimal symptoms prospectively underwent PET, echocardiography and cardiac magnetic resonance imaging (CMR) on the same day. PET was used to simultaneously measure cardiac output, LV mass and oxygen consumption to establish MEE. PET in patients were compared to healthy volunteers (n = 9). MEE and standard imaging indicators of regurgitation severity, LV volumes and function were studied as predictors of time to surgical intervention. Patients were followed median 3.0 years (interquartile range 2.0-3.8) and the endpoint was reached in 22 subjects (47%). MEE in patients reaching the endpoint (23.8±5.0%) was lower than in censored patients (28.5±4.5%, P = 0.002) and in healthy volunteers (30.1±4.9%, 0.001). MEE with a cut-off lower than 25.7% was significantly associated with the outcome (hazard ratio of 7.5 (95%CI: 2.7-20.6, p<0.0001) and retained independent significance when compared to standard imaging parameters.

Conclusion: MEE independently predicted time to progression requiring valve surgery in patients with asymptomatic moderate-severe or severe primary MR. The study suggests that inefficient myocardial oxidative metabolism precedes clinically observed progression in MR.

OBJECTIVES: Patients with severe primary mitral regurgitation (PMR) remain asymptomatic at first. In the long term, however, severe PMR leads to cardiac decompensation. Exercise testing in asymptomatic PMR is recommended in selected patients by guidelines. Cardiopulmonary exercise testing (CPET), which additionally measures ventilation (VE), oxygen consumption (VO₂) and carbon dioxide production (VCO₂), has been scarcely studied in PMR. We hypothesized that CPET might have prognostic value in asymptomatic PMR and therefore studied if CPET, including assessment of ventilation efficiency, has prognostic value for asymptomatic patients with severe PMR.

METHODS: Asymptomatic patients with severe PMR were prospectively recruited between 2013 and 2018. Exclusion criteria were coronary artery disease, chronic kidney disease, diabetes mellitus, concomitant valve disease, symptomatic lung disease or class 1 recommendation for valvular surgery. Echocardiography and serial CPET were conducted at one university hospital in Sweden. Primary outcome was mitral valve intervention.

RESULTS: Forty-eight patients were recruited to the study. Median follow-up period was 4.4 (2.1-6.9) years, during which 28 (58%) patients underwent mitral valve surgery. Ventilation efficiency, the relationship of VE to VCO₂ during CPET, predicted surgical treatment of the mitral valve. Increased VE/VCO₂ ratio at the anaerobic threshold had the highest predictive value, remaining an independent predictor after adjusting for impaired VO₂ at peak exercise (HR 4.42 (1.52-12.92), p = 0.007) and echocardiographic thresholds for left ventricular and atrial remodelling, as defined by current guideline-based recommendation for intervention (HR 3.72 (1.41-9.82), p = 0.008).

CONCLUSION: Impaired ventilatory efficiency, but not peak VO₂, predicted surgical treatment of the mitral valve in asymptomatic patients with severe PMR. Ventilatory efficiency, a CPET index less dependent on peak exercise performance, may be a new useful tool in risk stratification.