Fibrotic aortic valve disease after radiotherapy: an immunohistochemical study in breast cancer and lymphoma patients.

BACKGROUND: Radiation-associated aortic valve (AV) stenosis is frequently seen as a late sequela after thoracic radiotherapy (RT). Although the clinical relationship between thoracic radiotherapy and valvular dysfunction has been established, the process leading to accelerated aortic valve stenosis remains unclear. The aim of this study was to determine whether increased inflammatory cell infiltration, fibrosis, and calcification is present in aortic valves after radiotherapy at the time of aortic valve replacement. METHODS: Stenotic aortic valve specimens from 43 patients were obtained after surgical aortic valve replacement. A total 28 patients had previously undergone radiotherapy for breast cancer or malignant lymphoma. A total 15 patients were included as control. The valve leaflets were assessed by (immuno)histochemistry for inflammatory cell composition (CD3, CD20, CD68, and CD163) and extracellular matrix changes (collagen and calcification). RESULTS: Aortic valve cell density after radiotherapy for lymphoma was markedly decreased when compared with other groups. Irradiated aortic valve show similar (low) degrees of late T and B lymphocyte infiltration as control valves, whereas macrophage marker CD68 was decreased after radiotherapy for breast cancer. Collagen content was increased following radiotherapy. Aortic valves of patients with lymphoma contained significantly less calcified tissue when compared with the other groups. CONCLUSION: High-dose radiation at a young age (patients with lymphoma) results in cell loss and premature fibrotic aortic valve stenosis as opposed to the degenerative calcific stenosis observed in patients with breast cancer. Our findings suggest a possible dose-dependent effect of radiotherapy on aortic valve fibrosis. The active presence of inflammatory cells may be limited to the acute phase after radiotherapy.

Nutrition before and during Surgery and the Inflammatory Response of the Heart: A Randomized Controlled Trial.

Major surgery induces a long fasting time and provokes an inflammatory response which increases the risk of infections. Nutrition given before and during surgery can avoid fasting and has been shown to increase the arginine/asymmetric dimetlhylarginine ratio, a marker of nitric oxide availability, in cardiac tissue and increased concentrations of branched chain amino acids in blood plasma. However, the effect of this new nutritional strategy on organ inflammatory response is unknown. Therefore, we studied the effect of nutrition before and during cardiac surgery on myocardial inflammatory response. In this trial, 32 patients were randomised between enteral, parenteral, and no nutrition supplementation (control) from 2 days before, during, up to 2 days after coronary artery bypass grafting. Both solutions included proteins or amino acids, glucose, vitamins, and minerals. Myocardial atrial tissue was sampled before and after revascularization and was analysed immunohistochemically, subdivided into cardiomyocytic, fatty, and fibrotic areas. Inflammatory cells, especially leukocytes, were present in cardiac tissue in all study groups. No significant differences were found in the myocardial inflammatory response between the enteral, parenteral, and control groups. In conclusion, nutrition given before and during surgery neither stimulates nor diminishes the myocardial inflammatory response in patients undergoing coronary artery bypass grafting. The trial was registered in Netherlands Trial Register (NTR): NTR2183.

Nutrition before, during, and after surgery increases the arginine:asymmetric dimethylarginine ratio and relates to improved myocardial glucose metabolism: a randomized controlled trial.

BACKGROUND: Nitric oxide (NO) is essential for the optimal perfusion of the heart and its vasculature. NO may be insufficient in surgical patients because its precursor arginine is decreased, and the inhibitor of NO synthesis asymmetric dimethylarginine (ADMA) is increased. Besides arginine, the presence of other amino acids essential for the proper metabolism of cardiac cells may be decreased too. Supplementation of these amino acids with enteral and parenteral nutrition before, during, and after surgery may augment the myocardial and plasma arginine:ADMA ratio and availability of amino acids. Myocardial glucose metabolism and nutritional conditioning may result in a reduction of cardiac injury and support rapid recovery after major surgery. OBJECTIVE: We investigated the effect of nutrition before, during, and after surgery on amino acids and the myocardial arginine:ADMA ratio and its relation to myocardial glucose metabolism. DESIGN: In this trial, 33 patients who were undergoing off-pump coronary artery bypass grafting (CABG) were randomly assigned between enteral, parenteral, or no nutrition (control) from 2 d before, during, and until 2 d after surgery. Both enteral and parenteral solutions were prepared with commercially available products and included proteins or amino acids, glucose, vitamins, and minerals. Concentrations of amino acids including ADMA were analyzed in myocardial tissue and plasma samples. ¹8F-fluorodeoxyglucose positron emission tomography was performed before and after surgery to assess myocardial glucose metabolism. RESULTS: The myocardial arginine:ADMA ratio increased during surgery and was significantly higher in the enteral and parenteral groups than in the control group [median (IQR): 115.0 (98.0-142.2) (P = 0.012), 116.9 (100.3-135.3) (P = 0.004), and 93.3 (82.7-101.1), respectively]. Furthermore, the change in the preoperative to postoperative plasma arginine:ADMA ratio correlated with the change in myocardial glucose metabolism in positron emission tomography (r = 0.427, P = 0.033). CONCLUSION: Enteral or parenteral nutrition before, during, and after CABG may positively influence myocardial glucose metabolism by increasing the plasma and myocardial arginine:ADMA ratio.

Epicardial and endocardial electrophysiological guided thoracoscopic surgery for atrial fibrillation: a multidisciplinary approach of atrial fibrillation ablation in challenging patients.

INTRODUCTION: Patients with atrial fibrillation (AF) with enlarged atria or previous pulmonary vein isolation (PVI) are challenging patients for catheter ablation. Thoracoscopic surgery is an effective treatment for these patients but comes at the cost of an increase in adverse events. Recently, electrophysiological (EP) guided approaches to thoracoscopic surgery have been described which consist of EP guidance by measurement of conduction block across ablation lines. In this study we describe the efficacy and safety of EP-guided thoracoscopic surgery for AF in patients with enlarged atria and/or prior failed catheter ablation. METHODS & RESULTS: A total of 72 patients were included. Two different approaches to EP-guided thoracoscopic surgery were implemented: epicardial or endocardial EP-guidance at the time of surgery. Residual intraoperative conduction requiring additional ablation was detected with epicardial or endocardial mapping techniques in 50% and 11%, respectively. Additional epicardial or endocardial ablation was performed until bidirectional block was confirmed. Follow-up consisted of an ECG and a 24h Holter at 3, 6 and 12 months after the procedure. A total of 57 patients (79%) had freedom of AF and were off anti-arrhythmic drugs at one year follow-up (30 paroxysmal (83%), 27 persistent AF (75%)). Adverse events occurred in 13 patients (6 major). None of our patients died and all events were reversible. CONCLUSION: EP-guidance of thoracoscopic surgery can be safely performed both epicardially and endocardially and is associated with a high rate of long-term maintenance of sinus rhythm in patients with enlarged atria and/or a previously failed ablation.

The role of asymmetric dimethylarginine and arginine in the failing heart and its vasculature.

Nitric oxide (NO) is formed from arginine by the enzyme nitric oxide synthase (NOS). Asymmetric dimethylarginine (ADMA) can inhibit NO production by competing with arginine for NOS binding. Therefore, the net amount of NO might be indicated by the arginine/ADMA ratio. In turn, arginine can be metabolized by the enzyme arginase, and ADMA by the enzyme dimethylarginine dimethylaminohydrolase (DDAH). While ADMA has been implicated as a cardiovascular risk factor, arginine supplementation has been indicated as a treatment in cardiac diseases. This review discusses the roles of ADMA and arginine in the failing heart and its vasculature. Furthermore, it proposes nutritional therapies to improve NO availability.