Samuel Heuts

Modalities and Effects of Left Ventricle Unloading on Extracorporeal Life support: a Review of the Current Literature

Veno‐arterial extracorporeal membrane oxygenation (V‐A ECMO) support is increasingly used in refractory cardiogenic shock and cardiac arrest, but is characterized by a rise in afterload of the left ventricle (LV) which may ultimately either further impair or delay cardiac contractility improvement. The aim of this study was to provide a comprehensive overview regarding the different LV venting techniques and results currently available in the literature.

Comparing the endo-aortic balloon and the external aortic clamp in minimally invasive mitral valve surgery

OBJECTIVES The aim of this study was to assess the differences in perioperative outcomes and complications between the endo-aortic balloon (EAB) and the external aortic clamp (EAC) during primary elective minimally invasive mitral valve surgery (MIMVS) in a single referral centre by one surgeon. Primary outcomes were cardiopulmonary bypass time (CPB), cross-clamp time (CX) and occurrence of postoperative cerebrovascular accidents (CVAs). Secondary outcomes were other perioperative parameters and complications. METHODS We retrospectively analysed 340 consecutive patients who underwent MIMVS for mitral regurgitation (MR), mitral stenosis or combined regurgitation/stenosis between November 2010 and March 2014 in a single referral centre. In total, 221 patients who underwent an isolated mitral valve repair or isolated mitral valve replacement or repair/replacement combined with an atrial fibrillation (AF)-ablation procedure were included. Patients who had previous cardiac surgery or concomitant tricuspid valve surgery, myxoma or atrial septal defect closure surgery were excluded. RESULTS A total of 57 patients (Group A) underwent MIMVS using the EAC and 164 patients (Group B) were operated using an EAB. Preoperative variables showed a significant difference in poor left ventricular function (LVF, P = 0.18) and moderate LVF (P = 0.019). No significant differences were found in CPB-time, cross-clamp time or postoperative CVA. Furthermore, no significant differences were found in complications, 30-day mortality or postoperative echocardiographical MR gradation. Hospital stay, however, was prolonged in Group A (P = 0.001) and maximum troponin T levels were significantly lower in Group B (P = 0.014). In Group B however, 10 procedures were converted (6%) from EAB to EAC. CONCLUSIONS There is no difference in use between the EAB and the EAC in terms of CPB-time and cross-clamp time, complications or MR gradation at discharge. Use of the EAC showed significantly higher postoperative levels of troponin T, implying more myocardial damage, compared with the EAB. In 6% of the cases however, patients were converted from the EAB to the EAC.

Preoperative planning with three-dimensional reconstruction of patient's anatomy, rapid prototyping and simulation for endoscopic mitral valve repair

Objectives Mitral valve repair performed by an experienced surgeon is superior to mitral valve replacement for degenerative mitral valve disease; however, many surgeons are still deterred from adapting this procedure because of a steep learning curve. Simulation-based training and planning could improve the surgical performance and reduce the learning curve. The aim of this study was to develop a patient-specific simulation for mitral valve repair and provide a proof of concept of personalized medicine in a patient prospectively planned for mitral valve surgery. Methods A 65-year old male with severe symptomatic mitral valve regurgitation was referred to our mitral valve heart team. On the basis of three-dimensional (3D) transoesophageal echocardiography and computed tomography, 3D reconstructions of the patients anatomy were constructed. By navigating through these reconstructions, the repair options and surgical access were chosen (minimally invasive repair). Using rapid prototyping and negative mould fabrication, we developed a process to cast a patient-specific mitral valve silicone replica for preoperative repair in a high-fidelity simulator. Results Mitral valve and negative mould were printed in systole to capture the pathology when the valve closes. A patient-specific mitral valve silicone replica was casted and mounted in the simulator. All repair techniques could be performed in the simulator to choose the best repair strategy. As the valve was printed in systole, no special testing other than adjusting the coaptation area was required. Subsequently, the patient was operated, mitral valve pathology was validated and repair was successfully done as in the simulation. Conclusions The patient-specific simulation and planning could be applied for surgical training, starting the (minimally invasive) mitral valve repair programme, planning of complex cases and the evaluation of new interventional techniques. The personalized medicine could be a possible pathway towards enhancing reproducibility, patients safety and effectiveness of a complex surgical procedure.

Preoperative planning of left-sided valve surgery with 3D computed tomography reconstruction models: sternotomy or a minimally invasive approach?

OBJECTIVES With the emergence of a new concept aimed at individualization of patient care, the focus will shift from whether a minimally invasive procedure is better than conventional treatment, to the question of which patients will benefit most from which technique? The superiority of minimally invasive valve surgery (MIVS) has not yet been proved. We believe that through better patient selection advantages of this technique can become more pronounced. In our current study, we evaluate the feasibility of 3D computed tomography (CT) imaging reconstruction in the preoperative planning of patients referred for MIVS. METHODS We retrospectively analysed all consecutive patients who were referred for minimally invasive mitral valve surgery (MIMVS) and minimally invasive aortic valve replacement (MIAVR) to a single surgeon in a tertiary referral centre for MIVS between March 2014 and 2015. Prospective preoperative planning was done for all patients and was based on evaluations by a multidisciplinary heart-team, an echocardiography, conventional CT images and 3D CT reconstruction models. RESULTS A total of 39 patients were included in our study; 16 for mitral valve surgery (MVS) and 23 patients for aortic valve replacement (AVR). Eleven patients (69%) within the MVS group underwent MIMVS. Five patients (31%) underwent conventional MVS. Findings leading to exclusion for MIMVS were a tortuous or slender femoro-iliac tract, calcification of the aortic bifurcation, aortic elongation and pericardial calcifications. Furthermore, 2 patients had a change of operative strategy based on preoperative planning. Seventeen (74%) patients in the AVR group underwent MIAVR. Six patients (26%) underwent conventional AVR. Indications for conventional AVR instead of MIAVR were an elongated ascending aorta, ascending aortic calcification and ascending aortic dilatation. One patient (6%) in the MIAVR group was converted to a sternotomy due to excessive intraoperative bleeding. Two mortalities were reported during conventional MVS. There were no mortalities reported in the MIMVS, MIAVR or conventional AVR group. CONCLUSIONS Preoperative planning of minimally invasive left-sided valve surgery with 3D CT reconstruction models is a useful and feasible method to determine operative strategy and exclude patients ineligible for a minimally invasive approach, thus potentially preventing complications.

Aortic elongation part II: the risk of acute type A aortic dissection

Objectives Prophylactic surgery for prevention of acute type A aortic dissection (ATAAD) is reserved for patients with an ascending aortic aneurysm ≥55 mm. Identification of additional risk predictors is warranted since over 70% of patients presenting with ATAAD have a non-dilated aorta or an aneurysm that would not have met the diameter criterion for preventative surgery. Aim of the study was to evaluate ascending aortic elongation as a risk factor for ATAAD and to compare aortic lengths between ATAAD patients and healthy controls. Methods Aortic lengths and diameters of ATAAD patients were measured on three-dimensional modelled computed tomography and adjusted to predissection dimensions in this cross-sectional single-centre study. Logistic regression was used to evaluate the relation between ATAAD and aortic dimensions. Lengths of different aortic segments were compared with a healthy control group using propensity score matching. Results Two-hundred and fifty patients were included in the study (ATAAD, n=40; controls, n=210). Ascending aortic length and diameter proved to be independent predictors for ATAAD (OR=5.3, CI 2.5 to 11.4, p<0.001 and OR=8.6, CI 2.4 to 31.0, p=0.001). Eighty patients were matched based on propensity scores (ATAAD n=40, controls n=40). The ascending aorta was longer and more dilated in ATAAD patients compared with healthy controls (78.6±8.8 mm vs 68.9±7.2 mm, p<0.001, 34.4 mm ±3.2. vs 39.4 mm ±5.7, p<0.001, respectively). No differences were found in lengths of the aortic arch and descending aorta. Conclusions Ascending aortic length could serve as an independent predictor for ATAAD. Future studies addressing indications for prophylactic surgery should also investigate aortic length.

Aortic elongation part I: the normal aortic ageing process

Objectives Differentiation between normal and abnormal features of vascular ageing is crucial, as the latter is associated with adverse outcomes. The normal aortic ageing process is accompanied by gradual luminal dilatation and reduction of vessel compliance. However, the influence of age on longitudinal aortic dimensions and geometry has not been well studied. This study aims to describe the normal evolution of aortic length and shape throughout life. Methods A total of 210 consecutive patients were prospectively enrolled in this cross-sectional single-centre study. All subjects underwent CT on a third-generation dual-source CT scanner. Morphometric measurements, including measurements of segmental length and tortuosity, were performed on three-dimensional models of the thoracic aorta. Results The length of the thoracic aorta was significantly related to age (r=0.54) and increased by 59 mm (males) or 66 mm (females) between the ages of 20 and 80 years. Elongation was most pronounced in the proximal descending aorta, which showed an almost 2.5-fold length increase during life. The lengthening of the thoracic aorta was accompanied by a marked change of its geometry: whereas the aortic apex was located between the branch vessels in younger patients, it shifted to a more distalward position in the elderly. Conclusions The normal ageing process is accompanied by gradual aortic elongation and a notable change of aortic geometry. Part II of this two-part article investigates the hypothesis that excessive elongation could play a role in the occurrence of acute aortic dissection.

Mitral valve modelling and three-dimensional printing for planning and simulation of mitral valve repair

OBJECTIVES The aim of this study was to develop a process for modelling and 3-dimensional (3D) printing of different mitral valve diseases for procedural planning and simulation, based on 3D transoesophageal echocardiography (TOE). METHODS 3D TOE was used to reconstruct a fully dynamic 3D view of the diseased valve. Reconstructions were cropped at the level of the valve and captured in mid-systole to assess the coaptation defect. Reconstructions were then exported as a surface mesh. To ensure a watertight and noise-reduced model, the mesh was processed using computer-modelling programmes, whereupon the valve was printed in 3D. For simulation purposes, deformable models were created based on negative mould fabrication and cast in tissue-mimicking silicone. Model validation was performed by intraoperative assessment of the valvular disease and repair strategy. RESULTS The mitral valves of 10 prospective patients with different diseases were modelled. In 6 patients, a 3D printed rigid plastic mitral valve was created for procedural planning, and in 4 patients, a silicone-cast replica was created for procedural simulation. All models were created to scale, implying conservation of in vivo dimensions. Models were validated by in vivo comparison. Total workaround time ranged from 3 to 4 h and 2 to 3 days for rigid plastic and silicone models, respectively. Costs were €15 to €40 and €300, respectively. CONCLUSIONS We demonstrated the feasibility of creating rigid plastic and tissue-mimicking silicone mitral valve replications. These models could be used in the future to enhance surgical anatomical interpretation, to facilitate planning and simulation of complex surgeries and for training purposes.

Antegrade type A aortic dissection under endoscopic vision during minimally invasive mitral valve repair: a case report

A 68-year-old woman was referred for surgical correction of severe mitral valve regurgitation and underwent minimally invasive mitral valve repair (MIMVS). Per-procedurally, the patient developed an antegrade type A aortic dissection (TAD) under endoscopic vision, while slightly manipulating the ascending aorta. An emergency sternotomy was performed, and the antegrade TAD, as well as the mitral regurgitation were dealt with accordingly. The patient had a normal aortic diameter but an elongated aorta. This case prompted us to alter our method of preoperative planning by implementing computed tomography angiography in the work-up of every patient for MIMVS. Furthermore, following this case we demonstrated aortic elongation to be a potential risk factor for TAD and considered this to be a relative contraindication for MIMVS.

Correction to: Antithrombotic therapy after mitral valve repair: VKA or aspirin?

The original version of this article unfortunately contained a mistake in the author name. The co-author name should be Frederikus A. Klok instead of Frederik A. Klok. The original article has been corrected.

The unstoppable heart: an aortocoronary fistula in coronary artery bypass grafting

This case report describes a coronary bypass surgery case in which cardioplegic arrest was impossible due to an aortacoronary fistula that was visualized using 3-dimensional computer tomography (CT) angiography postoperatively. Aortacoronary fistulas are protective in coronary artery disease but can severely complicate cardiac surgery and might require CT imaging in the preoperative workup.