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OBJECTIVES: Transapical valve implantation is traditionally performed through a left antero-lateral mini-thoracotomy. A self-expandable apical closure device has recently been developed for full-percutaneous transapical valve implantation. We performed haemodynamics stress-tests on an animal model to evaluate the sealing properties. METHODS: Under general anaesthesia 5 pigs (mean weight: 67 ± 6 Kg) received full heparinization (100 IU/Kg; activated clotting time >250 s and, through inferior mini-sternotomies, 21-Fr introducer sheaths for transapical aortic valve implantation (outer diameter: 25-Fr) were placed over-the-wire in the apexes. Delivery-catheters carrying folded occluders (SAFEXTM final design) were inserted in the introducer sheaths and plugs were then deployed under fluoroscopic guidance. Phase 1: after protamine injection, apical bleeding was monitored for 1 h with standard haemodynamics condition. Phase 2: we induced systemic hypertension with adrenaline infusion to test the sealing properties under stress. Animals were sacrificed after Phase 2 and hearts were removed and inspected. RESULTS: Five plugs were successfully introduced and deployed in 5 pig hearts. Plugs provided good apical sealing in each animal and a mean of 7 ± 4 ml of blood lost per animal was collected during Phase 1: haemodynamics remained stable and no plug dislodgement was detected (mean blood pressure: 52 ± 9 mmHg). During Phase 2, mean systolic and diastolic peak levels reached 268 ± 24 mmHg and 175 ± 17 mmHg, respectively, without plug dislodgment or bleeding. Post-mortem inspection showed good plug deployment and fixation without myocardial damage. CONCLUSIONS: The new apical occluder seals large-sized apical access sites in animal models also during induced systemic hypertension. This pilot study is a further step towards full-percutaneous transapical valve procedures in the clinical setting.

Objective: To determine the optimal venous tubing diameter for adult cardiopulmonary bypass (CPB) to improve gravity drainage and to reduce priming volume. Methods: (A) Maximum bovine blood flow rates by gravity drainage were assessed in vitro for four different tubing diameters (1/2, 3/8, 5/16,1/4 inch) with three different lengths and various pre- and afterloads. Based on the results of (A) and multiple regression analyses, we developed equations to predict tubing sizes as a function of target flows. (C) The equations obtained in (B) were validated by ex vivo bovine experiments. (D) The clinically required maximal flows were determined retrospectively by reviewing 119 perfusion records at Zurich University. (E) Based on our model (B), the clinical patient and hardware requirements, the optimal venous tubing diameter was calculated. (F) The optimized venous tubing was evaluated in a prospective clinical trial involving 312 patients in Hangzhou. Results: For a mean body surface area of 1.83±0.2 m2, the maximal perfusion flow rate (D) achieved with 1/2-inch (=1.27 cm2) venous tubing was 4.62±0.57 l/min (range: 2.50-6.24 l/min). Our validated model (B,C) predicted 1.0 cm2 as optimal cross-sectional area for the venous line. New tubing packs developed accordingly were used routinely thereafter. The maximal flow rate was 4.93±0.58 l/min (range: 3.9-7.0) in patients with a mean body surface area of 1.62±0.21 m2. Conclusion: The new venous tubing with 1.0-cm2 cross-sectional area improves the drainage in the vast majority of adult patients undergoing CPB and reduces the priming volume (−27 ml/m). Reduced hemodilution can prevent homologous transfusions if a predefined transfusion trigger level is not reached

OBJECTIVES The aim was to evaluate the impact of a bicuspid aortic valve (BAV) on local shear stress and on the pressure profile on the elements of the aortic root (AoR). METHODS The experiment setup included a BAV with aortic valve stenosis (n = 5 pigs, 67 ± 3.5 kg) and insufficiency (n = 5 pigs, 66.7 ± 4.4 kg). By implanting 6 high-fidelity microsonometric crystals in each AoR, we determined the 3-dimensional (3D) geometry of the AoR. Experimental and geometric data were used to create a 3D time- and pressure-dependent computed fluid dynamic model of the AoR with the BAV. RESULTS 3D AoR geometry was determined by AoR tilt (α) and rotation angle (β). Both values were maximal at the end of diastole: 24.41 ± 1.70° (α) and 20.90 ± 2.11° (β) for BAV with stenosis and 31.92 ± 11.51° (α) and 20.84 ± 9.80° (β) for BAV with insufficiency and minimal at peak ejection 23.42 ± 1.65° (α), 20.38 ± 1.61° (β) for stenosis and 26.62 ± 7.86° (α), 19.79 ± 8.45° (β) for insufficiency. In insufficiency, low shear stress of 0-0.08 Pa and moderate pressure (60-80 mmHg) were present. In BAV with stenosis, low shear stress of 0-0.5 Pa and moderate pressure (0-20 mmHg) were present at diastole; at peak ejection high shear stress >2 Pa and elevated pressure of >80 mmHg were present. CONCLUSIONS In a BAV with aortic valve stenosis, the haemodynamics are less favourable. The elevated pressure with elevated shear stress may over the long term promote degenerative processes in the leaflets and consequently valve function failure.

Despite the efficacy of cardiac surgery, less invasive interventions with more uncertain long-term outcomes are increasingly challenging surgery as first-line treatment for several congenital, degenerative and ischemic cardiac diseases. The specialty must evolve if it is to ensure its future relevance. More importantly, it must evolve to ensure that future patients have access to treatments with proven long-term effectiveness. This cannot be achieved without dynamic leadership; however, our contention is that this is not enough. The demands of a modern surgical career and the importance of the task at hand are such that the serendipitous emergence of traditional charismatic leadership cannot be relied upon to deliver necessary change. We advocate systematic analysis and strategic leadership at a local, national and international level in four key areas: Clinical Care, Research, Education and Training, and Stakeholder Engagement. While we anticipate that exceptional individuals will continue to shape the future of our specialty, the creation of robust structures to deliver collective leadership in these key areas is of paramount importance

Objective: Although recent experience suggests that transmyocardial laser revascularisation (TMLR) relieves angina, its mechanism of action remains undefined. We examined its functional effects and analysed its morphological features in an animal model of acute ischaemia. Methods: A total of 15 pigs were randomised to ligation of left marginal arteries (infarction group, n=5), to TMLR of the left lateral wall using a holmium:yttrium-aluminium garnet (Ho:YAG) laser (laser group, n=5), and to both (laser-infarction group, n=5). All the animals were sacrificed 1 month after the procedure. Haemodynamics and echocardiography with segmental wall motion score were carried out at both time intervals (scale 0-3: 0, normal; 1, hypokinesia; 2, akinesia; 3, dyskinesia). Histology of the involved area was analysed. Results: Laser group showed no change of the segmental wall motion score of the involved area 30 min after the laser channels were made (score: 0±0). Infarction and laser-infarction groups both showed a persistent and definitive increase of the segmental wall motion score (at 30 min: 1.6±0.3 and 2±0, respectively; at 1 month: 1.8±0.2 and 1.8±0.4, respectively). These increases were all statistically significant in comparison with baseline values (P