Percutaneous and Minimally Invasive Valve Procedures

Large Animal Translational Validation of 3 Mitral Valve Repair Operations for Mitral Regurgitation Using a Mitral Valve Prolapse Model: A Comprehensive In Vivo Biomechanical Engineering Analysis

BACKGROUND

Various mitral repair techniques have been described. Though these repair techniques can be highly effective when performed correctly in suitable patients, limited quantitative biomechanical data are available. Validation and thorough biomechanical evaluation of these repair techniques from translational large animal in vivo studies in a standardized, translatable fashion are lacking. We sought to evaluate and validate biomechanical differences among different mitral repair techniques and further optimize repair operations using a large animal mitral valve prolapse model.

METHODS

Male Dorset sheep (n=20) had P2 chordae severed to create the mitral valve prolapse model. Fiber Bragg grating force sensors were implanted to measure chordal forces. Ten sheep underwent 3 randomized, paired mitral valve repair operations: neochord repair, nonresectional leaflet remodeling, and triangular resection. The other 10 sheep underwent neochord repair with 2, 4, and 6 neochordae. Data were collected at baseline, mitral valve prolapse, and after each repair.

RESULTS

All mitral repair techniques successfully eliminated regurgitation. Compared with mitral valve prolapse (0.54±0.18 N), repair using neochord (0.37±0.20 N; P=0.02) and remodeling techniques (0.30±0.15 N; P=0.001) reduced secondary chordae peak force. Neochord repair further decreased primary chordae peak force (0.21±0.14 N) to baseline levels (0.20±0.17 N; P=0.83), and was associated with lower primary chordae peak force compared with the remodeling (0.34±0.18 N; P=0.02) and triangular resectional techniques (0.36±0.27 N; P=0.03). Specifically, repair using 2 neochordae resulted in higher peak primary chordal forces (0.28±0.21 N) compared with those using 4 (0.22±0.16 N; P=0.02) or 6 neochordae (0.19±0.16 N; P=0.002). No difference in peak primary chordal forces was observed between 4 and 6 neochordae (P=0.05). Peak forces on the neochordae were the lowest using 6 neochordae (0.09±0.11 N) compared with those of 4 neochordae (0.15±0.14 N; P=0.01) and 2 neochordae (0.29±0.18 N; P=0.001).

CONCLUSIONS

Significant biomechanical differences were observed underlying different mitral repair techniques in a translational large animal model. Neochord repair was associated with the lowest primary chordae peak force compared to the remodeling and triangular resectional techniques. Additionally, neochord repair using at least 4 neochordae was associated with lower chordal forces on the primary chordae and the neochordae. This study provided key insights about mitral valve repair optimization and may further improve repair durability.

Strategy for Totally Percutaneous Management of Vascular Injury in Combined Transfemoral Transcatheter Aortic Valve Replacement and Endovascular Aortic Aneurysm Repair Procedures

Minimally invasive treatment of severe aortic stenosis by transcatheter aortic valve replacement (TAVR) and infrarenal abdominal aortic aneurysm by endovascular aortic aneurysm repair (EVAR) requires large-bore vascular access. These percutaneous transfemoral interventions may be performed as a combined procedure, however, vascular injury may necessitate surgical vascular repair. We implemented a strategy designed to enable percutaneous vascular repair, with stent-graft implantation, if necessary, after these combined procedures. We identified all combined percutaneous TAVR and EVAR procedures which were performed at our institution. Patient and procedural characteristics and clinical outcomes were analyzed. Six consecutive patients underwent total percutaneous combined TAVR and EVAR procedures. In all cases, TAVR was performed first and was followed by EVAR. Both common femoral arteries served as primary access sites for delivery of the implanted devices and hemostasis was achieved by deployment of vascular closure devices. Secondary access sites included the right brachial artery in all patients and superficial femoral arteries in 50% of the patients. In all cases an "0.014" 300-cm length "safety" wire was delivered to the common femoral artery or descending aorta by way of a secondary access site to facilitate stent graft delivery. Successful device implantation was achieved in all cases. Vascular closure device failure occurred in 2 patients and was treated by stent graft implantation by way of the brachial and superficial femoral arteries, without need for surgical vascular repair. A strategy designed to facilitate percutaneous vascular repair after combined EVAR and TAVR procedures may enable a truly minimally invasive procedure.

Anaesthesia for Minimally Invasive Cardiac Surgery

Minimally invasive cardiac surgery (MICS) has been used since the 1990s and encompasses a wide range of techniques that lack full sternotomy, including valve and coronary artery graft surgery as well as transcatheter procedures. Due to the potential benefits offered to patients by MICS, these procedures are becoming more common. Unique anaesthetic knowledge and skills are required to overcome the specific challenges presented by MICS, including mastery of transoesophageal echocardiography (TOE) and the provision of thoracic regional analgesia. This review evaluates the relevance of MICS to the anaesthetist and discusses pre-operative assessment, the relevant adjustments to intra-operative conduct that are necessary for these techniques, as well as post-operative care and what is known about outcomes.

Minimal-Access Atrial Septal Defect (ASD) Closure

Progress towards the development and adoption of minimally invasive techniques in cardiac surgery has been slower than that seen in other surgical specialties. Congenital heart disease (CHD) patients represent an important population within cardiac disease, of which atrial septal defect (ASD) is one of the most common diagnoses. Management of ASD encompasses a range of minimal-access and minimally invasive approaches, including transcatheter device closure, mini-sternotomy, thoracotomy, video-assisted, endoscopic, and robotic approaches. In this article, we will discuss the pathophysiology of ASD, along with diagnosis, management, and indications for intervention. We will review the current evidence supporting minimally invasive and minimal-access surgical ASD closure in the adult and paediatric patient, highlighting peri-operative considerations and areas for further research.

High-flow nasal oxygen vs. standard oxygen therapy for patients undergoing transcatheter aortic valve replacement with conscious sedation: a randomised controlled trial

BACKGROUND

Minimally invasive surgery is becoming more common and transfemoral transcatheter aortic valve replacement is offered to older patients with multiple comorbidities. Sternotomy is not required but patients must lie flat and still for up to 2-3 h. This procedure is increasingly being performed under conscious sedation with supplementary oxygen, but hypoxia and agitation are commonly observed.

METHODS

In this randomised controlled trial, we hypothesised that high-flow nasal oxygen would provide superior oxygenation as compared with our standard practice, 2 l min^-1 oxygen by dry nasal specs. This was administered using the Optiflow THRIVE Nasal High Flow delivery system (Fisher and Paykel, Auckland, New Zealand) at a flow rate of 50 l min^-1 and FiO₂ 0.3. The primary endpoint was the change in arterial partial pressure of oxygen (pO₂) during the procedure. Secondary outcomes included the incidence of oxygen desaturation, airway interventions, the number of times the patient reached for the oxygen delivery device, incidence of cerebral desaturation, peri-operative oxygen therapy duration, hospital length of stay and patient satisfaction scores.

RESULTS

A total of 72 patients were recruited. There was no difference in change in pO₂ from baseline using high-flow compared with standard oxygen therapy: median [IQR] increase from 12.10 (10.05-15.22 [7.2-29.8]) to 13.69 (10.85-18.38 [8.5-32.3]) kPa vs. decrease from 15.45 (12.17-19.33 [9.2-22.8]) to 14.20 (11.80-19.40 [9.7-35.1]) kPa, respectively. The percentage change in pO2 after 30 min was also not significantly different between the two groups (p = 0.171). There was a lower incidence of oxygen desaturation in the high-flow group (p = 0.027). Patients in the high-flow group assigned a significantly higher comfort score to their treatment (p ≤ 0.001).

CONCLUSION

This study has demonstrated that high flow, compared with standard oxygen therapy, does not improve arterial oxygenation over the course of the procedure. There are suggestions that it may improve the secondary outcomes studied.

TRIAL REGISTRATION

International Standard Randomised Controlled Trial Number (ISRCTN) 13,804,861. Registered on 15 April 2019. https://doi.org/10.1186/ISRCTN13804861.

Complications Associated With Transesophageal Echocardiography in Transcatheter Structural Cardiac Interventions

BACKGROUND

Transesophageal echocardiograms (TEEs) performed during transcatheter structural cardiac interventions may result in greater complications than those performed in the nonoperative setting or even those performed during cardiac surgery. However, there are limited data on complications associated with TEE during these procedures. We evaluated the prevalence of major complications among these patients in the United States.

METHODS

A retrospective cohort study was conducted using an electronic health record database (TriNetX Research Network) from large academic medical centers across the United States for patients undergoing TEE during transcatheter structural interventions from January 2012 to January 2022. Using the American Society of Echocardiography-endorsed International Statistical Classification of Diseases and Related Health Problems Clinical Modifications (10th edition) codes, patients undergoing TEE during a transcatheter structural cardiac intervention, including transaortic, mitral or tricuspid valve repair, left atrial appendage occlusion, atrial septal defect closure, patent foramen ovale closure, and paravalvular leak repair, were identified. The primary outcome was major complications within 72 hours of the procedure (composite of bleeding and esophageal and upper respiratory tract injury). The secondary aim was the frequency of major complications, death, or cardiac arrest within 72 hours in patients who completed intraoperative TEE during surgical valve replacement.

RESULTS

Among 12,043 adult patients (mean age, 74 years old; 42% female) undergoing TEE for transcatheter structural cardiac interventions, 429 (3.6%) patients had a major complication. Complication frequency was higher in patients on anticoagulation or antiplatelet therapy compared with those not on therapy (3.9% vs 0.5%; risk ratio [RR] = 8.09, P < .001). Compared with those patients <65 years of age, patients ≥65 years of age had a higher frequency of major complications (3.9% vs 2.2%; RR = 1.75, P < .001). Complication frequency was similar among male and female patients (3.5% vs 3.7%; RR = 0.96, P = .67). Among 28,848 patients who completed surgical valve replacement with TEE guidance, 728 (2.5%) experienced a major complication.

CONCLUSIONS

This study found that more than 3% of patients undergoing TEE during transcatheter structural cardiac interventions have a major complication, which is more common among those on anticoagulant or antiplatelet therapy or who are elderly. With a shift of poor surgical candidates to less invasive percutaneous procedures, the future of TEE-guided procedures relies on comprehensive risk discussion and updating practices beyond conventional methods to minimize risk for TEE-related complications.

Effect of minimally invasive cardiac surgery compared with conventional surgery on post-operative physical activity and rehabilitation in patients with valvular heart disease

Background

Minimally invasive cardiac surgery (MICS) has steadily become more and more popular. MICS is less invasive and has a faster return to normality after surgery. Patients who had MICS continue to exercise more frequently than those who had the conventional median sternotomy surgery. It is generally established that physical activity lowers mortality and the risk of cardiac disease. The purpose of the study: is to evaluate and compare physical activity levels in MICS and conventional surgery.

Result

The level of preoperative physical activity did not significantly differ between the two groups. However, the MICS group significantly exceeded the conventional group in terms of postoperative progress, amount of physical activity, and 6-minute walking test. Also, Visual Analog Scale (VAS) score was significantly less.

Conclusion

Minimally invasive cardiac surgery has a higher margin of benefit, and speedy recovery to normality, which is accompanied by a lower VAS score and increased physical activity in comparison to conventional surgery.

Minimally-invasive cardiac surgery: a bibliometric analysis of impact and force to identify key and facilitating advanced training

Background

The number of citations an article receives is a marker of its scientific influence within a particular specialty. This bibliometric analysis intended to recognise the top 100 cited articles in minimally-invasive cardiac surgery, to determine the fundamental subject areas that have borne considerable influence upon clinical practice and academic knowledge whilst also considering bibliometric scope. This is increasingly relevant in a continually advancing specialty and one where minimally-invasive cardiac procedures have the potential for huge benefits to patient outcomes.

Methods

The Web of Science (Clarivate Analytics) data citation index database was searched with the following terms: [Minimal* AND Invasive* AND Card* AND Surg*]. Results were limited to full text English language manuscripts and ranked by citation number. Further analysis of the top 100 cited articles was carried out according to subject, author, publication year, journal, institution and country of origin.

Results

A total of 4716 eligible manuscripts were retrieved. Of the top 100 papers, the median (range) citation number was 101 (51–414). The most cited paper by Lichtenstein et al. (Circulation 114(6):591–596, 2006) published in Circulation with 414 citations focused on transapical transcatheter aortic valve implantation as a viable alternative to aortic valve replacement with cardiopulmonary bypass in selected patients with aortic stenosis. The Annals of Thoracic Surgery published the most papers and received the most citations (n = 35; 3036 citations). The United States of America had the most publications and citations (n = 52; 5303 citations), followed by Germany (n = 27; 2598 citations). Harvard Medical School, Boston, Massachusetts, published the most papers of all institutions. Minimally-invasive cardiac surgery pertaining to valve surgery (n = 42) and coronary artery bypass surgery (n = 30) were the two most frequent topics by a large margin.

Conclusions

This work establishes a comprehensive and informative analysis of the most influential publications in minimally-invasive cardiac surgery and outlines what constitutes a citable article. Undertaking a quantitative evaluation of the top 100 papers aids in recognising the contributions of key authors and institutions as well as guiding future efforts in this field to continually improve the quality of care offered to complex cardiac patients.

Regional anesthesia techniques for cardiac surgery: where are we?

PURPOSE OF REVIEW

Inadequate pain relief after cardiac surgery results in decreased patient experience and satisfaction, increased opioid consumption with its associated adverse consequences, and reduced efficiency metrics. To mitigate this, regional analgesic techniques are an increasingly important part of the perioperative cardiac anesthesia care plan. The purpose of this review is to compare current regional anesthesia techniques, and the relative evidence supporting their efficacy and safety in cardiac surgery.

RECENT FINDINGS

Numerous novel plane blocks have been developed in recent years, with evidence of improved pain control after cardiac surgery.

SUMMARY

The current data supports the use of a variety of different regional anesthesia techniques to reduce acute pain after cardiac surgery. However, future randomized trials are needed to quantify and compare the efficacy and safety of different regional techniques for pain control after cardiac surgery.

Comorbidity Trends in Patients Requiring Sternectomy and Reconstruction: Updated Data Analysis From 2005 to 2020

INTRODUCTION

Comorbidity trends after median sternectomy were studied at our institution by Vasconze et al (Comorbidity trends in patients requiring sternectomy and reconstruction. Ann Plast Surg. 2005;54:5). Although techniques for sternal reconstruction have remained unchanged, the patient population has become more complex in recent years. This study offers insight into changing trends in this patient population.

METHODS

A retrospective review was performed of patients who underwent median sternectomy followed by flap reconstruction at out institution between 2005 and 2020. Comorbidities, reconstruction method, average laboratory values, and complications were analyzed.

RESULTS

A total of 105 patients were identified. Comorbidities noted were diabetes (27%), immunosuppression (16%), hypertension (58%), renal insufficiency (23%), chronic obstructive pulmonary disease (16%), and tobacco utilization (24%). The most common reconstruction methods were omentum (45%) or pectoralis major flaps (34%). Thirty-day mortality rates were 10%, and presence of at least 1 complication was 34% (hematoma, seroma, osteomyelitis, dehiscence, wound infection, flap failure, and graft exposure). Univariate analysis demonstrated that sex (P = 0.048), renal insufficiency, surgical site complication, wound dehiscence, and flap failure (P < 0.05) had statistically significant associations with mortality. In addition, body mass index, creatinine, and albumin had a significant univariate association with mortality (P < 0.05).

CONCLUSIONS

Similar to the original study, there is an association between renal insufficiency and mortality. However, the mortality rate is decreased to 10%, likely because of improved medical management of patients with increasing comorbidities (80% with greater than one comorbidity). This has led to the increased use of omentum as a first-line option. Subsequent wound dehiscence and flap failure demonstrate an association with mortality, suggesting that increasingly complex patients are requiring a method of reconstruction once used a last resort as a first-line option.

Perceval S, sutureless aortic valve: cost-consequence analysis

INTRODUCTION

Sutureless aortic valve prostheses have the potential of shortening ischemic time.

AIM

We conducted the present study to assess the clinical and economic impact of the biological, sutureless, self-expanding Perceval S valve since the effect of shortened operative times on hospital costs remains unclear.

MATERIAL AND METHODS

This is a retrospective analysis. From January 2018 to January 2019, 29 patients underwent isolated aortic valve replacement with the Crown PRT bioprosthetic Aortic Valve, whereas 35 patients underwent aortic valve replacement with Perceval S (auto-expanded, sutureless, bioprosthesis). Preoperative data, hospital outcome, and health care resource consumption were compared, using χ² and t-test.

RESULTS

Aortic cross-clamp, cardiopulmonary bypass, and operation times were significantly shorter in the Perceval S group (p < 0.001). Patients in the sutureless group required blood transfusion less frequently (p = 0.03) and had a shorter intensive care unit (ICU) stay (p = 0.01). Hospital stay (p = 0.57) and pacemaker implantation were similar between groups. The reduction of aortic cross-clamp, extracorporeal circulation times, and ICU stay resulted in reduced resource consumption in the sutureless group.

CONCLUSIONS

The use of the Perceval S valve is clinically safe and effective. A shorter procedural time in the sutureless group is associated with better clinical outcomes and reduced hospital costs.

Biomechanical engineering comparison of four leaflet repair techniques for mitral regurgitation using a novel 3-dimensional-printed left heart simulator

Objective

Mitral valve repair is the gold standard treatment for degenerative mitral regurgitation; however, a multitude of repair techniques exist with little quantitative data comparing these approaches. Using a novel ex vivo model, we sought to evaluate biomechanical differences between repair techniques.

Methods

Using porcine mitral valves mounted within a custom 3-dimensional-printed left heart simulator, we induced mitral regurgitation using an isolated P2 prolapse model by cutting primary chordae. Next, we repaired the valves in series using the edge-to-edge technique, neochordoplasty, nonresectional remodeling, and classic leaflet resection. Hemodynamic data and chordae forces were measured and analyzed using an incomplete counterbalanced repeated measures design with the healthy pre-prolapse valve as a control.

Results

With the exception of the edge-to-edge technique, all repair methods effectively corrected mitral regurgitation, returning regurgitant fraction to baseline levels (baseline 11.9% ± 3.7%, edge-to-edge 22.5% ± 6.9%, nonresectional remodeling 12.3% ± 3.0%, neochordal 13.4% ± 4.8%, resection 14.7% ± 5.5%, P < 0.01). Forces on the primary chordae were minimized using the neochordal and nonresectional techniques whereas the edge-to-edge and resectional techniques resulted in significantly elevated primary forces. Secondary chordae forces also followed this pattern, with edge-to-edge repair generating significantly higher secondary forces and leaflet resection trending higher than the nonresectional and neochord repairs.

Conclusions

Although multiple methods of degenerative mitral valve repair are used clinically, their biomechanical properties vary significantly. Nonresectional techniques, including leaflet remodeling and neochordal techniques, appear to result in lower chordal forces in this ex vivo technical engineering model.

A computational optimization study of a self-expandable transcatheter aortic valve

Developing an efficient stent frame for transcatheter aortic valves (TAV) needs thorough investigation in different design and functional aspects. In recent years, most TAV studies have focused on their clinical performance, leaflet design, and durability. Although several optimization studies on peripheral stents exist, the TAV stents have different functional requirements and need to be explicitly studied. The aim of this study is to develop a cost-effective optimization framework to find the optimal TAV stent design made of Ni-Ti alloy. The proposed framework focuses on minimizing the maximum strain occurring in the stent during crimping, making use of a simplified model of the stent to reduce computational cost. The effect of the strut cross-section of the stent, i.e., width and thickness, and the number and geometry of the repeating units of the stent (both influencing the cell size) on the maximum strain is investigated. Three-dimensional simulations of the crimping process are used to verify the validity of the simplified representation of the stent, and the radial force has been calculated for further evaluation. The results suggest the key role of the number of cells (repeating units) and strut width on the maximum strain and, consequently, on the stent design. The difference in terms of the maximum strain between the simplified and the 3D model was less than 5%, confirming the validity of the adopted modeling strategy and the robustness of the framework to improve the TAV stent designs through a simple, cost-effective, and reliable procedure.

Mitral chordae tendineae force profile characterization using a posterior ventricular anchoring neochordal repair model for mitral regurgitation in a three-dimensional-printed ex vivo left heart simulator

OBJECTIVES

Posterior ventricular anchoring neochordal (PVAN) repair is a non-resectional technique for correcting mitral regurgitation (MR) due to posterior leaflet prolapse, utilizing a single suture anchored in the myocardium behind the leaflet. This technique has demonstrated clinical efficacy, although a theoretical limitation is stability of the anchoring suture. We hypothesize that the PVAN suture positions the leaflet for coaptation, after which forces are distributed evenly with low repair suture forces.

METHODS

Porcine mitral valves were mounted in a 3-dimensional-printed heart simulator and chordal forces, haemodynamics and echocardiography were collected at baseline, after inducing MR by severing chordae, and after PVAN repair. Repair suture forces were measured with a force-sensing post positioned to mimic in vivo suture placement. Forces required to pull the myocardial suture free were also determined.

RESULTS

Relative primary and secondary chordae forces on both leaflets were elevated during prolapse (P < 0.05). PVAN repair eliminated MR in all valves and normalized chordae forces to baseline levels on anterior primary (0.37 ± 0.23 to 0.22 ± 0.09 N, P < 0.05), posterior primary (0.62 ± 0.37 to 0.14 ± 0.05 N, P = 0.001), anterior secondary (1.48 ± 0.52 to 0.85 ± 0.43 N, P < 0.001) and posterior secondary chordae (1.42 ± 0.69 to 0.59 ± 0.17 N, P = 0.005). Repair suture forces were minimal, even compared to normal primary chordae forces (0.08 ± 0.04 vs 0.19 ± 0.08 N, P = 0.002), and were 90 times smaller than maximum forces tolerated by the myocardium (0.08 ± 0.04 vs 6.9 ± 1.3 N, P < 0.001).

DISCUSSION

PVAN repair eliminates MR by positioning the posterior leaflet for coaptation, distributing forces throughout the valve. Given extremely low measured forces, the strength of the repair suture and the myocardium is not a limitation.

From less invasive to minimal invasive extracorporeal circulation

Development of minimally invasive cardiac surgery (MICS) served the purpose of performing surgery while avoiding the surgical stress triggered by a full median sternotomy. Minimizing surgical trauma is associated with improved cosmesis and enhanced recovery leading to reduced morbidity. However, it has to be primarily appreciated that the extracorporeal circulation (ECC) stands for the basis of nearly all MICS procedures. With some fundamental modification and advancement in perfusion techniques, the use of ECC has become the enabling technology for the development of MICS. Less invasive cardiopulmonary bypass (CPB) techniques are based on remote cannulation and optimization of perfusion techniques with assisted venous drainage and use of centrifugal pump, so as to facilitate the demanding surgical maneuvers, rather than minimizing the invasiveness of the CPB. This is reflected in the increased duration of CPB required for MICS procedures. Minimal invasive Extracorporeal Circulation (MiECC) represents a major breakthrough in perfusion. It integrates all contemporary technological advancements that facilitate best applying cardiovascular physiology to intraoperative perfusion. Consequently, MiECC use translates to improved end-organ protection and clinical outcome, as evidenced in multiple clinical trials and meta-analyses. MICS performed with MiECC provides the basis for developing a multidisciplinary intraoperative strategy towards a "more physiologic" cardiac surgery by combining small surgical trauma with minimum body's physiology derangement. Integration of MiECC can advance MICS from non-full sternotomy for selected patients to a "more physiologic" surgery, which represents the real face of modern cardiac surgery in the transcatheter era.

Anesthesia for minimally invasive cardiac surgery

Due to its potential benefits and increased patient satisfaction minimal invasive cardiac surgery (MICS) is rapidly gaining in popularity. These procedures are not without challenges and require careful planning, pre-operative patient assessment and excellent intraoperative communication. Assessment of patient suitability for MICS by a multi-disciplinary team during pre-operative workup is desirable. MICS requires additional skills that many might not consider to be part of the standard cardiac anesthetic toolkit. Anesthetists involved in MICS need not only be highly skilled in performing transesophageal echocardiography (TEE) but need to be proficient in multimodal analgesia, including locoregional or neuroaxial techniques. MICS procedures tend to cause more postoperative pain than standard median sternotomies do, and patients need analgesic management more in keeping with thoracic operations. Ultrasound guided peripheral regional anesthesia techniques like serratus anterior block can offer an advantage over neuroaxial techniques in patients on anti-platelet therapy or anticoagulation with low molecular weight or unfractionated heparin The article reviews the salient points pertaining to pre-operative assessment and suitability, intraoperative process and postoperative management of minimally invasive cardiac procedures in the operating theatre as well as the catheterization lab. Special emphasis is given to anesthetic management and analgesia techniques.

Minimally invasive mitral valve repair

Minimally invasive mitral valve (MV) repair is being increasingly performed over the last 2 decades due to the constantly growing patient demand, since it offers a shorter recovery, less restriction and faster return to normal physical activities, reduction in pain, and superior cosmetic results. However, such procedures have to be performed through small incisions which limit visualization and the freedom of movement of the surgeon, in contrast to conventional operations that are performed through a sternotomy. Therefore, special long surgical instruments are required, and visualization is usually enhanced with advanced port-access two-dimensional (2D) or three-dimensional (3D) thoracoscopic cameras. This makes performance of a minimally invasive MV repair more challenging for the surgeon and is thereby associated with a steep learning curve. Nonetheless, the vast majority of patients who require MV repair are usually good candidates for this less invasive technique, though adequate patient selection is of utmost importance for success. Concomitant cardiac procedures such as ablation surgery for atrial fibrillation or right-sided interventions such as tricuspid valve surgery, heart tumor resection, and atrial septal defect closure can easily be performed using this approach. Short- and long-term results after minimally invasive MV repair are excellent and comparable with those achieved through a sternotomy approach. There are few drawbacks associated with minimally invasive MV repair such as the high technical demands of working through a constrained space and development of complications associated with peripheral cannulation and seldom unilateral pulmonary edema. Nonetheless, high-volume centers have been able to achieve similar operating times, postoperative complication rates, and mid-/long-term outcomes to those obtained through conventional sternotomy. Up-to-date evidence is needed in order to improve recommendations supporting minimally invasive MV repair. Future innovations should concentrate on decreasing complexity and improving reproducibility of minimally invasive procedures in low-volume centers.

Benefits of rapid deployment aortic valve replacement with a mini upper sternotomy

BACKGROUND

Surgical aortic valve replacement (AVR) is currently deemed the gold standard of care for patients with severe aortic stenosis. Currently, most AVRs are safely performed through a full median sternotomy approach. With an increasingly elderly and high-risk patient population, major advances in valve technology and surgical technique have been introduced to reduce perioperative risk and post-operative complications associated with the full sternotomy approach, in order to ensure surgical AVR remains the gold standard. For example, minimally invasive approaches (most commonly via mini sternotomy) have been developed to improve patient outcomes. The advent of rapid deployment valve technology has also been shown to improve morbidity and mortality by reducing cardiopulmonary bypass and aortic cross-clamp times, as well as facilitating the use of minimal access approaches. Rapid deployment valves were introduced into our department at the Royal Infirmary of Edinburgh in 2014. The aim of this study is to investigate if utilising the combination of rapid deployment valves and a mini sternotomy minimally invasive approach resulted in improved outcomes in various patient subgroups.

METHODS

Over a 3-year period, we identified 714 patients who underwent isolated AVR in our centre. They were divided into two groups: 61 patients (8.5%) were identified who received rapid deployment AVR via J-shaped mini upper sternotomy (MIRDAVR group), whilst 653 patients (91.5%) were identified who received either a full sternotomy (using a conventional prosthesis or rapid deployment valve) or minimally invasive approach using a conventional valve (CONVAVR group). We retrospectively analysed data from our cardiac surgery database, including pre-operative demographics, intraoperative times and postoperative outcomes. Outcomes were also compared in two different subgroups: octogenarians and high-risk patients.

RESULTS

Pre-operative demographics showed that there were significantly more female and elderly patients in the MIRDAVR group. The MIRDAVR group had significantly reduced cardiopulmonary bypass (63.7 min vs. 104 min, p = 0.0001) and aortic cross-clamp times (47.3 min vs. 80.1 min, p = 0.0001) compared to the CONVAVR group. These results were particularly significant in the octogenarian population, who also had a reduced length of ICU stay (30.9 h vs. 65.6 h, p = 0.049). In high-risk patients (i.e. logistic EuroSCORE I > 10%), minimally invasive-rapid deployment aortic valve replacement is still beneficial and is also characterized by significantly shorter cardiopulmonary bypass time (69.1 min vs. 96.1 min, p = 0.03). However, post-operative correlations, such as length of ICU stay, become no more significant, likely due to serious co-morbidities in this patient group.

CONCLUSION

We have demonstrated that minimally invasive rapid deployment aortic valve replacement is associated with significantly reduced cardiopulmonary bypass and aortic cross-clamp times. This correlation is much stronger in the octogenarian population, who were also found to have significantly reduced length of ICU stay. Our study raises the suggestion that this approach should be utilised more frequently in clinical practice, particularly in octogenarian patients.

Does minimal invasive cardiac surgery reduce the incidence of post-operative atrial fibrillation?

Atrial fibrillation (AF) is the most common post-operative complication and tends to be the most common arrhythmia after cardiac surgery. The etiology and risk factors for post-operative AF are poorly understood, but older age, large left atrium, diffuse coronary artery disease, a history of AF paroxysms and in general, pre-existing cardiac conditions that cause restricting and susceptibility towards inflammation have been consistently linked with post-operative atrial fibrillation (POAF). It has been traditionally thought that post-operative AF is transient, well-tolerated, benign to the patient and self-limiting complication of cardiac surgery that was temporary and easily treated. However, recent evidence suggests that POAF may be more "malignant" than previously thought, associated with follow-up mortality and morbidity. Several minimally invasive approaches, including the right parasternal approach, upper and lower mini-sternotomy (MS), V-shaped, Z-shaped, inverse-T, J-, reverse-C and reverse-L partial MS, transverse sternotomy and right mini-thoracotomy, have been developed for cardiac surgery operations since 1993 and have been associated with better outcomes and lower perioperative morbidity compared to full sternotomy (FS). The common goal of several minimally invasive approaches is to reduce invasiveness and surgical trauma. According to a statement from the American Heart Association (AHA), the term "minimally invasive" refers to a small chest wall incision that does not include a FS. This review is aimed to evaluate the use of minimally invasive techniques like mini-sternotomy, mini-thoracotomy and hybrid techniques versus conventional techniques which are used in cardiac surgery and to compare the frequency of post-operative AF and its effect on post-operative complications, morbidity and mortality, after cardiac surgery operations with FS versus cardiac surgery operations with the use of minimally invasive techniques.

Reasons for conversion and adverse intraoperative events in Endoscopic Port Access™ atrioventricular valve surgery and minimally invasive aortic valve surgery

OBJECTIVES

This study reports the factors that contribute to sternotomy conversions (SCs) and adverse intraoperative events in minimally invasive aortic valve surgery (MI-AVS) and minimally invasive Endoscopic Port Access™ atrioventricular valve surgery (MI-PAS).

METHODS

In total, 3780 consecutive patients with either aortic valve disease or atrioventricular valve disease underwent minimally invasive valve surgery (MIVS) at our institution between 1 February 1997 and 31 March 2016. MI-AVS was performed in 908 patients (mean age 69.2 ± 11.3 years, 45.2% women, 6.2% redo cardiac surgery) and MI-PAS in 2872 patients (mean age 64.1 ± 13.3 years, 46.7% women, 12.2% redo cardiac surgery).

RESULTS

A cumulative total of 4415 MIVS procedures (MI-AVS = 908, MI-PAS = 3507) included 1537 valve replacements (MI-AVS = 896, MI-PAS = 641) and 2878 isolated or combined valve repairs (MI-AVS = 12, MI-PAS = 2866). SC was required in 3.0% (n = 114 of 3780) of MIVS patients, which occurred in 3.1% (n = 28 of 908) of MI-AVS patients and 3.0% (n = 86 of 2872) of MI-PAS patients, respectively. Reasons for SC in MI-AVS included inadequate visualization (n = 4, 0.4%) and arterial cannulation difficulty (n = 7, 0.8%). For MI-PAS, SC was required in 54 (2.5%) isolated mitral valve procedures (n = 2183). Factors that contributed to SC in MI-PAS included lung adhesions (n = 35, 1.2%), inadequate visualization (n = 2, 0.1%), ventricular bleeding (n = 3, 0.1%) and atrioventricular dehiscence (n = 5, 0.2%). Neurological deficit occurred in 1 (0.1%) and 3 (3.5%) MI-AVS and MI-PAS conversions, respectively. No operative or 30-day mortalities were observed in MI-AVS conversions (n = 28). The 30-day mortality associated with SC in MI-PAS (n = 86) was 10.5% (n = 9).

CONCLUSIONS

MIVS is increasingly being recognized as the 'gold-standard' for surgical valve interventions in the context of rapidly expanding catheter-based technology and increasing patient expectations. Surgeons need to be aware of factors that contribute to SC and adverse intraoperative outcomes to ensure that patients enjoy the maximum potential benefit of MIVS and to apply effective risk reduction strategies that encourage safer and sustainable MIVS programmes.

Minimally invasive surgical aortic valve replacement

Minimally invasive aortic valve replacement (MIAVR) is defined as a surgical aortic valve replacement which involves smaller chest incisions as opposed to full sternotomy. It is performed using cardiopulmonary bypass with cardiac arrest. It benefits from potential advantages of a less invasive procedure. To date, over 14 000 MIAVR have been reported in the literature. Due to heterogeneity of the studies, different surgical techniques and mainly the non-randomised nature of these studies comparing MIAVR with conventional aortic valve replacement, it is difficult to draw definitive conclusions. The two main techniques of MIAVR are mini-sternotomy and right anterior mini-thoracotomy. Both techniques with other less common forms of MIAVR will be discussed in this review. The advantages, disadvantages and surgical pitfalls will be discussed. Some of the advantages include shorter intensive care and hospital stay, reduced perioperative blood loss, less pain, improved respiratory function and cosmesis. The possible disadvantage of longer bypass and cross-clamp times may be counter balanced by the recent sutureless and rapid deployment valves. Despite some of the benefits, MIAVR has not been adopted by a significant proportion of the surgeons possibly related to the learning curve and requirements for re-training. As MIAVR becomes more common, randomised trials comparing this technique with transcatheter aortic valve implantation is warranted. In addition, assessing quality of life including return to work and functional capacity is needed.

A retrospective study of conscious sedation versus general anaesthesia in patients scheduled for transfemoral aortic valve implantation: A single center experience

OBJECTIVES

The current 2017 ESC/EACTS guidelines recommend transcatheter aortic valve implantations (TAVIs) as the therapy of choice for inoperable patients with severe symptomatic aortic stenosis. Most of the TAVIs worldwide are performed under general anaesthesia (GA). Although conscious sedation (CS) concepts are increasingly applied in Europe, it is still a matter of debate which concept is associated with highest amount of safety for this high-risk patient population. The aim of this single center, before-and-after study was to investigate feasibility and safety of CS compared with GA with respect to peri-procedural complications and 30-day mortality in patients scheduled for transfemoral TAVI (TF-TAVI).

METHODS

From March 2012 until September 2014, patients scheduled for the TF-TAVI procedure were included in a prospective, observational manner. From the 200 patients finally included, 107 procedures were performed under GA, using either an endotracheal tube or a laryngeal mask, and balanced anaesthesia. CS was performed in 93 patients using low-dose propofol and remifentanil.

RESULTS

Conversion to GA was needed 4 times due to procedural-related complications (4.3%), in one patient due to ongoing agitation (1.1%). The CS-group showed significantly shorter key time courses: anaesthesia time (105 [95-120] minutes vs 115 [105-140] minutes, P-value = 0.009, Mann-Whitney-U-test) and length of stay in the intensive care unit (1.6 [1.0-1.5] d vs 2.1 [1.0-2.0] d, P-value = 0.002, Mann-Whitney-U-test). The lowest mean arterial pressure was significantly higher in the CS-group compared with the GA-group (74.3 mmHg vs 55.2 mmHg, P-value <0.0001, t-test). CS was associated with less requirements of norepinephrine (0.1 μg/kg vs 2.3 μg/kg, P-value <0.0001, Mann-Whitney-U-test).

CONCLUSIONS

Our single-center data demonstrate that CS is a feasible and safe alternative, especially with respect to a higher degree of intra-procedural haemodynamic stability, and a reduced length of stay in the intensive care unit.

Beneficial effects of percutaneous minimally invasive surgery for patients with fractures in the thoracic spine

Percutaneous minimally invasive surgery (PMIS) is the most common surgical procedure used in patients with fractures in the thoracic spine. In the present study, the benefits of PMIS compared with the conventional open surgery (COS) were investigated in patients with thoracic spine fractures. A total of 84 patients were recruited in the current analysis. Inflammatory responses were measured in all patients subsequent to PMIS and COS. It was demonstrated that PMIS produced reduced inflammatory responses as compared with COS in clinical patients. In addition, the results revealed that kyphosis, anterolisthesis and the neurological state were significantly improved in patients subjected to PMIS compared with those receiving COS (P<0.01). The mean values of bone reduction and fracture correction loss were similar in the PMIS and COS groups (4.5 degrees). Furthermore, the outcomes indicated that the sensitivity for fracture localization to the correct vertebra was 0.90 in PMIS and 0.92 in COS (P>0.05). It was observed that patients who had undergone PMIS required reduced hospitalization time compared with the COS-treated patients (P=0.026). Additionally, the mean bleeding volume during surgery was 538 ml in the PMIS patients and 845 ml in the COS patients. Regarding physical activity, patients who underwent PMIS were relative more active compared with the COS patients (P=0.038) in a 14-day observation. In conclusion, the current clinical analysis indicated that PMIS was more beneficial for the treatment of patients with fractures in the thoracic spine, and the study provided further evidence for the management thoracic spine injuries.

A computed tomography-based planning tool for predicting difficulty of minimally invasive aortic valve replacement

OBJECTIVES

Minimally invasive aortic valve replacement has proven its value over the last decade by its significant advancement and reduction in mortality, morbidity and admission time. However, minimally invasive aortic valve replacement is associated with some on-site difficulties such as limited aortic annulus exposure. Currently, computed tomography scans are used to evaluate the anatomical relationship among the intercostal spaces, ascending aorta and aortic valve prior to surgery. We hypothesized that quantitative measurements of access distance and access angle are associated with outcome and access difficulty.

METHODS

We introduce a novel minimally invasive aortic valve replacement planning prototype that allows automatic measurements of access angle, access distance and aortic annulus dimensions. The prototype visualizes these measurements on the chest cage as ISO contours. The association of these measures with outcome parameters such as extracorporeal circulation time, aortic cross-clamping time and access difficulty score was assessed. We included 14 patients who received a new valve by ministernotomy.

RESULTS

The mean access angle was 40.3 ± 5.1°. It was strongly associated with aortic cross-clamping time (Pearson correlation coefficient = 0.60, P = 0.02) and access difficulty score (Spearman's rank correlation coefficient = 0.57, P = 0.03). Access angles were significantly different between easy and difficult access groups (P = 0.03). There was no significant association between access distance and outcome parameters.

CONCLUSIONS

Access angle is strongly associated with procedure complexity. The automated presentation of this measure suggests added value of the prototype in clinical practice.

Harmony Feasibility Trial: Acute and Short-Term Outcomes With a Self-Expanding Transcatheter Pulmonary Valve

OBJECTIVES

This study sought to obtain in vivo data to confirm assumptions on device loading conditions and assess procedural feasibility, safety, and valve performance.

BACKGROUND

The Harmony transcatheter pulmonary valve (Medtronic, Minneapolis, Minnesota) was designed for patients with severe pulmonary regurgitation who require pulmonary valve replacement.

METHODS

Three sites participated in this first Food and Drug Administration-approved early feasibility study using an innovative device design to accommodate the complex anatomy of the right ventricular outflow tract. Potentially eligible patients underwent review by a screening committee to determine implant eligibility. Six-month outcomes are reported.

RESULTS

Between May 2013 and May 2015, 66 subjects were enrolled, and 21 were approved for implant and underwent catheterization; 20 were implanted. Catheterized patients had a median age of 25 years, were predominantly diagnosed with tetralogy of Fallot (95%), had severe pulmonary regurgitation (95%), and had trivial or mild stenosis. The device was delivered in the desired location in 19 of 20 (95%) patients. Proximal migration occurred in 1 patient during delivery system removal. Two devices were surgically explanted. Premature ventricular contractions related to the procedure were reported in 3 patients; 2 were resolved without treatment. One patient had ventricular arrhythmias that required treatment and later were resolved. At 1 month, echocardiography revealed none or trivial pulmonary regurgitation in all and a mean right ventricular outflow tract gradient of 16 ± 8 mm Hg (range 6 to 31 mm Hg).

CONCLUSIONS

In this feasibility study of the Harmony transcatheter pulmonary valve device, there was high procedural success and safety, and favorable acute device performance.

Aortic valve bypass surgery in severe aortic valve stenosis: Insights from cardiac and brain magnetic resonance imaging

OBJECTIVE

To investigate and describe the distribution of aortic and cerebral blood flow (CBF) in patients with severe valvular aortic stenosis (AS) before and after aortic valve bypass (AVB) surgery.

METHODS

We enrolled 10 consecutive patients who underwent AVB surgery for severe AS. Cardiovascular magnetic resonance imaging (CMR) and brain magnetic resonance imaging were performed as baseline before surgery and twice after surgery. Quantitative flow measurements were obtained using 1.5-T magnetic resonance imaging (MRI) scanner phase-contrast images of the ascending aorta, descending thoracic aorta (3 cm proximally and distally from the conduit-to-aorta anastomosis), and ventricular outflow portion of the conduit. The evaluation of CBF was performed using 3.0-T MRI scanner arterial spin labeling (ASL) through sequences acquired at the gray matter, dorsal default-mode network, and sensorimotor levels.

RESULTS

Conduit flow, expressed as the percentage of total antegrade flow through the conduit, was 63.5 ± 8% and 67.8 ± 7% on early and mid-term postoperative CMR, respectively (P < .05). Retrograde perfusion from the level of the conduit insertion in the descending thoracic aorta toward the aortic arch accounted for 6.9% of total cardiac output and 11% of total conduit flow. We did not observe any significant reduction in left ventricular stroke volume at postoperative evaluation compared with preoperative evaluation (P = .435). No differences were observed between preoperative and postoperative CBF at the gray matter, dorsal default-mode network, and sensorimotor levels (P = .394).

CONCLUSIONS

After AVB surgery in patients with severe AS, cardiac output is split between the native left ventricular outflow tract and the apico-aortic bypass, with two-thirds of the total antegrade flow passing through the latter and one-third passing through the former. In our experience, CBF assessment confirms that the flow redistribution does not jeopardize cerebral blood supply.

Quality of life, satisfaction and outcomes after ministernotomy versus full sternotomy isolated aortic valve replacement (QUALITY-AVR): study protocol for a randomised controlled trial

BACKGROUND

During the last decade, the use of ministernotomy in cardiac surgery has increased. Quality of life and patient satisfaction after ministernotomy have never been compared to conventional full sternotomy in randomised trials. The aim of the study is to determine if this minimally invasive approach improves quality of life, satisfaction and clinical morbimortality outcomes.

METHODS/DESIGN

The QUALITY-AVR trial is a single-blind, single-centre, independent, and pragmatic randomised clinical trial comparing ministernotomy ("J" shaped upper hemisternotomy toward right 4th intercostal space) to full sternotomy in patients with isolated severe aortic stenosis scheduled for elective aortic valve replacement. One hundred patients will be randomised in a 1:1 computational fashion. Sample size was determined for the primary end point with alpha error of 0.05 and with power of 90% in detecting differences between intervention groups of ≥ 0.10 points in change from baseline quality of life Questionnaire EuroQOL-index (EQ-5D-5 L®), measured at 1, 6 or 12 months. Secondary endpoints are: the differences in change from other baseline EQ-5D-5 L® utilities (visual analogue scale, Health Index and Severity Index), cardiac surgery specific satisfaction questionnaire (SATISCORE®), a combined safety endpoint of four major adverse complications at 1 month (all-cause mortality, acute myocardial infarction, neurologic events and acute renal failure), bleeding through drains within the first 24 h, intubation time, postoperative hospital and intensive care unit length of stay, transfusion needs during the first 72 h and 1-year survival rates. Clinical follow up is scheduled at baseline, 1, 6, and 12 months after randomization. All clinical outcomes are recorded following the Valve Academic Research Consortium 2 criteria.

DISCUSSION

The QUALITY-AVR trial aims to test the hypothesis that ministernotomy improves quality of life, satisfaction and clinical outcomes in patients referred for isolated aortic valve replacement. Statistically significant differences favouring ministernotomy could modify the surgical "gold standard" for aortic stenosis surgery, and subsequently the need to change the control group in transcatheter aortic valve implantation trials. Recruitment started on 18 March 2016. In November 2017, 75 patients were enrolled.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02726087 . Registered on 13 March 2016.

Paediatric nanofibrous bioprosthetic heart valve

The search for an optimal aortic valve implant with durability, calcification resistance, excellent haemodynamic parameters and ability to withstand mechanical loading is yet to be met. Thus, there has been struggled to fabricate bio-prosthetics heart valve using bioengineering. The consequential product must be resilient with suitable mechanical features, biocompatible and possess the capacity to grow. Defective heart valves replacement by surgery is now common, this improves the value and survival of life for a lot of patients. The recent paediatric heart valve implant is suboptimal due to their inability of somatic growth. They usually have multiple surgeries to change outgrown valves. Short-lived valve bio-prostheses occurring in older patients and younger ones who more usually need the replacement of its damaged heart with prosthesis led to a new invasive surgical interventions with an improved quality of life. The authors propose that nanofibre scaffold for paediatric tissue-engineered heart valve will meet most of these conditions, most particularly those related to somatic growth, and, as the nanofibre scaffold is eroded, new valve is produced, the valve matures in the child until adulthood.

Five-year follow-up after transcatheter aortic valve implantation for symptomatic aortic stenosis

OBJECTIVES

Transcatheter aortic valve implantation (TAVI) has been implemented into the care of elderly patients suffering from severe symptomatic aortic stenosis. However, data on long-term follow-up are sparse and predictors of long-term mortality need to be evaluated to better select patients. Therefore, we aimed to analyse predictors of 5-year mortality after TAVI.

METHODS

We analysed data from the German Transcatheter Aortic Valve Interventions-Registry. Each of the 27 participating hospitals agreed to include all consecutive TAVI patients at their institution. Out of 1444 patients treated with TAVI, 1378 patients had a follow-up of at least 4.5 years (completeness 95.4%). Endpoint for this analysis was 5-year survival. Cox regression analysis was used to determine risk factors associated with this endpoint.

RESULTS

Patients who died were compared with survivors. The two groups showed multiple differences in patient characteristics, indications for interventions, preinterventional, as well as interventional characteristics and postinterventional events. Calculated 1-year mortality was 21.8% and 5-year mortality 59.1%. A higher logistic EuroScore was associated with a lower 5-year survival, being 45.5% in patients with a logistic EuroScore of <20%, 34.5% in those with 20% to 40% and 28.4% in patients with a logistic EuroScore >40%. Cox proportional hazard analysis revealed the following independent predictors of 5-year mortality: female gender (HR =0.66, 95% CI 0.56 to 0.77, p<0.0001), renal failure (HR=1.43, 95% CI 1.22 to 1.69, p<0.0001), prior mitral regurgitation ≥II° (HR=1.42, 95% CI 1.21 to 1.65, p<0.0001), residual aortic regurgitation ≥II° (HR=1.52, 95% CI 1.24 to 1.85, p<0.0001), atrial fibrillation (HR=1.38, 95% CI 1.18 to 1.64, p=0.0001), low gradient aortic stenosis (HR=1.48, 95% CI 1.19 to 1.84, p=0.0004), prior decompensation (HR=1.32, 95% CI 1.13 to 1.54, p=0.0006), frailty (HR=1.31, 95% CI 1.09 to 1.58, p=0.004), surgical TAVI (HR=1.42, 95% CI 1.12 to 1.80, p=0.004), age (by year) (HR=1.02, 95% CI 1.01 to 1.03, p=0.006), prior myocardial infarction (HR=1.29, 95% CI 1.07 to 1.57, p=0.009), urgent TAVI (HR=1.25, 95% CI 1.04 to 51, p=0.020) and diabetes mellitus (HR=1.20, 95% CI 1.02 to 1.40, p=0.024).

CONCLUSIONS

These data from the early TAVI experience show a 5-year mortality of 59.1%. Some of the predictors of 5-year mortality seem to be modifiable, such as residual aortic regurgitation, type of TAVI access route and concomitant mitral regurgitation.

Anatomical visualization of neural course and distribution of anterior ascending aortic plexus

The aim of this study was to document the detailed anatomy of neural course and distribution on the anterior ascending aorta, to identify the high and low density areas of the anterior ascending aortic plexus for further understandings in cardiovascular surgery. The embalmed hearts of 42 elderly individuals were submacroscopically and microscopically examined, after excluding any that were macroscopically abnormal. With its origins in the anterior ascending aortic plexus, the right coronary plexus substantially innervated the right coronary artery, the right atrium and ventricle, and the sinus node. The intensive neural area extending from 10 mm lateral to the interatrial groove below the pericardial reflection as far as the right coronary artery opening contained almost all the right coronary plexus in 61.3% of patients, and more than 40.9% of the total nerve volume of the anterior ascending aortic plexus. Our findings suggest that the most superior and lateral area on the ascending aorta show the lowest neural density of right coronary component in the anterior ascending aortic plexus and the high density areas are invisible in right lateral field of view as seen in the right trans-axillary MICS approach.

A multidisciplinary perioperative strategy for attaining "more physiologic" cardiac surgery

BACKGROUND

Cardiac surgery is, by definition, a "non-physiologic" intervention associated with systemic adverse effects. Despite advances in surgical technique, cardiopulmonary bypass (CPB) technology as well as anaesthesia management and patient care, there is still significant morbidity and subsequent mortality.

AIM

We consider that the contemporary demand for further improving patient outcome mandates the upgrade from optimal perfusion during the procedure as the gold standard to the concept of a "more physiologic" cardiac surgery. Our policy is a multidisciplinary perioperative strategy based on goal-directed perfusion throughout surgery incorporating in-line monitoring. This translates to "prevent rather than correct" malperfusion through real-time adjustment rather than correction of derangement detected late by incremental evaluation.

METHOD

The strategy is based on continuous monitoring of cardiac index, SvO₂, DO₂i, DO₂i/VCO₂i and rSO₂. Data acquisition is followed by action when needed; this includes stepwise: transfusion, increase of cardiac output and initiation of inotropic/vasoactive support. Moreover, implementation of minimally invasive extracorporeal circulation (MiECC) is considered as a fundamental component of physiologic perfusion when on-CPB, providing improved circulatory support and end-organ protection.

CONCLUSION

We consider that, with this strategy which establishes optimal perfusion perioperatively, we attain the goal of a "more physiologic" cardiac surgery.

Understanding the requirements of self-expandable stents for heart valve replacement: Radial force, hoop force and equilibrium

A proper interpretation of the forces developed during stent crimping and deployment is of paramount importance for a better understanding of the requirements for successful heart valve replacement. The present study combines experimental and computational methods to assess the performance of a nitinol stent for tissue-engineered heart valve implantation. To validate the stent model, the mechanical response to parallel plate compression and radial crimping was evaluated experimentally. Finite element simulations showed good agreement with the experimental findings. The computational models were further used to determine the hoop force on the stent and radial force on a rigid tool during crimping and self-expansion. In addition, stent deployment against ovine and human pulmonary arteries was simulated to determine the hoop force on the stent-artery system and the equilibrium diameter for different degrees of oversizing.

Dense motion field estimation from myocardial boundary displacements

Minimally invasive cardiovascular interventions guided by multiple imaging modalities are rapidly gaining clinical acceptance for the treatment of several cardiovascular diseases. These images are typically fused with richly detailed pre-operative scans through registration techniques, enhancing the intra-operative clinical data and easing the image-guided procedures. Nonetheless, rigid models have been used to align the different modalities, not taking into account the anatomical variations of the cardiac muscle throughout the cardiac cycle. In the current study, we present a novel strategy to compensate the beat-to-beat physiological adaptation of the myocardium. Hereto, we intend to prove that a complete myocardial motion field can be quickly recovered from the displacement field at the myocardial boundaries, therefore being an efficient strategy to locally deform the cardiac muscle. We address this hypothesis by comparing three different strategies to recover a dense myocardial motion field from a sparse one, namely, a diffusion-based approach, thin-plate splines, and multiquadric radial basis functions. Two experimental setups were used to validate the proposed strategy. First, an in silico validation was carried out on synthetic motion fields obtained from two realistic simulated ultrasound sequences. Then, 45 mid-ventricular 2D sequences of cine magnetic resonance imaging were processed to further evaluate the different approaches. The results showed that accurate boundary tracking combined with dense myocardial recovery via interpolation/diffusion is a potentially viable solution to speed up dense myocardial motion field estimation and, consequently, to deform/compensate the myocardial wall throughout the cardiac cycle. Copyright © 2015 John Wiley & Sons, Ltd.

Endoscopic atrioventricular valve surgery in adults with difficult-to-access uncorrected congenital chest wall deformities

OBJECTIVES

This study presents the first report on in-hospital and long-term outcomes of endoscopic port access atrioventricular valve surgery (EPAAVVS) in adult patients with uncorrected congenital chest wall deformities (CCWDs).

METHODS

Our current surgical team performed EPAAVVS in 7 consecutive adult patients (mean age 51.3 ± 16.4 years, 14.3% female, 50% older than 60 years, mean EuroSCORE II 0.8 ± 0.1%) with uncorrected CCWDs between 1 November 2009 and 30 November 2015. The mean left ventricular ejection fraction was 66.0 ± 8.5%. Surgical indications included isolated or combined symptomatic mitral valve (MV) regurgitation (n = 7, 100%), left ventricular outflow tract (LVOT) obstruction (n = 1, 14.3%) and patent foramen ovale (n = 3, 42.9%). Fibro-elastic deficiency accounted for 57.1% of MV pathology and 5 patients (74.1%) presented with New York Heart Association (NYHA) Class III symptoms. CCWDs included isolated pectus excavatum (n = 5, 71.4%) and mixed pectus excavatum and carinatum (n = 2, 28.6%). The mean Haller-index and correction index scores were 2.7 ± 0.5 and 21.4 ± 10.2%, respectively.

RESULTS

Procedures performed included MV repair (n = 7, 100%), tricuspid valve (TV) repair (n = 1, 14.3%) and left ventricular septal myomectomy (n = 1, 14.3%). There were no sternotomy conversions or complications with chest wall entry or atrioventricular valve exposure. The mean cardiopulmonary bypass and cross-clamp times were 162.1 ± 48.1 and 113.7 ± 33.5 min, respectively. No patient required mechanical ventilation or intensive care treatment longer than 24 h. There were no surgical revisions, in-hospital respiratory or chest wall morbidities. The mean length of hospital stay was 7.4 ± 1.0 days. A total of 208 patient-months (mean 29.7 ± 26.5) were available for long-term clinical and echocardiographic analysis. There were no 30-day or long-term mortalities and no patient required reintervention for residual atrioventricular valve pathology. All patients were classified as NYHA I during recent consultations, and echocardiographic follow-up confirmed no residual MV regurgitation greater than Grade 1 in any patient.

CONCLUSIONS

EPAAVVS in adults with uncorrected CCWD is safe, feasible and durable and can successfully be performed by experienced teams to achieve Haller index and correction index scores of up to 3.3 and 38.3%, respectively, with favourable long-term clinical and echocardiographic outcomes. The mere presence of uncorrected CCWDs should not deter surgeons from offering these patients the full benefits of minimally invasive cardiac surgery.

Early and long-term outcomes of minimally invasive mitral valve surgery through right minithoracotomy: a 10-year experience in 1604 patients

Background

To report early and long-term outcomes of patients undergoing minimally invasive mitral valve surgery (MIMVS) through right mini-thoracotomy (RT) over a 10-year period.

Methods

From September 2003 to December 2013, a total of 1604 consecutive patients underwent MIMVS through RT.

Results

The mean age was 63 ± 13 years, 770 (48 %) patients were female and 218 (13.6 %) had previous cardiac operations. The most predominant pathology was degenerative disease (70 %), followed by functional mitral valve regurgitation (12 %), rheumatic disease (9.4 %), endocarditis (5 %) and prosthetic dysfunction (3.2 %). Mitral valve repair was performed in 1137 (71 %) patients and 476 (29 %) had mitral valve replacement. Direct aortic cannulation was achieved in 1325 (83 %) patients. Among patients with degenerative disease candidate for repair (n = 958), rate of mitral valve repair was 95 %. Repair techniques included annuloplasty (95 %), leafleat resection (63 %), neochordae implantation (16 %) and sliding plasty (11 %). Concomitant procedures included tricuspid valve repair (14.6 %), atrial fibrillation ablation (9.5 %) and atrial septal defect closure (3.2 %). Overall in-hospital mortality was 1.1 %. Thirty-four patients (2.1 %) had conversion to sternotomy. Incidence of stroke was 2 %. Overall survival at 10 years was 88 ± 2 %. Freedom from reoperation at 10 years was 94 ± 2 % for repair and 80 ± 6 % for replacement. Freedom from recurrent mitral regurgitation >3+ at 10 years was 90 ± 3 %.

Conclusions

Minimally invasive mitral valve surgery is a safe and reproducible approach associated with low mortality and morbidity, high rate of mitral valve repair and excellent late results.

Late redo-port access surgery after port access surgery

OBJECTIVES

This study presents the first report on short- and long-term outcomes in redo-port access surgery after previous port access surgery (redo-PAS-PAS) for new or recurrent mitral valve (MV) and tricuspid valve (TV) disease.

METHODS

Our current surgical team performed redo-PAS-PAS in 26 consecutive patients who had previous port access surgery (mean age 65.8 ± 13.3 years, 46.2% female, 42.3% older than 70 years, mean logistical EuroSCORE 22.5 ± 21.6%) between 1 February 1997 and 30 June 2014. Surgical indications included among others MV prosthesis dysfunction (n = 8, 30.8%), endocarditis (n = 10, 38.5%) and TV dysfunction (n = 3, 11.5%). The mean time interval between primary PAS and redo-PAS-PAS was 70.32 ± 57.4 months.

RESULTS

Redo-PAS-PAS procedures included MV replacement (n = 19, 73.1%), MV repair (n = 5, 19.2%), and TV repair (n = 2, 7.7%). Sternotomy conversion was required in 5 patients (19.2%), of which 4 (15.4%) were early conversions due to lung adhesion and 1 (3.8%) due to a late intraoperative complication. The mean cardiopulmonary bypass and cross-clamp times were 163.3 ± 57.9 and 101.2 ± 43.8 min, respectively. Postoperative mechanical ventilation longer than 72 h was required in 4 patients (15.4%). In-hospital morbidities included hospital-acquired pneumonia (n = 3, 11.5%), postoperative air leaks (n = 2, 7.7%) and revision for bleeding (n = 1, 3.8%). The mean length of hospital stay was 16.1 days. Long-term clinical and echocardiographic follow-up were 48.3 ± 39.2 and 44.6 ± 32.9 months, respectively. The Kaplan-Meier analyses for survival and freedom from mitral and tricuspid valve reintervention (n = 26) at 5 years were 83.9 and 95.8%, respectively, with 91.3% of surviving patients classified as being NYHA II or less. Echocardiographic follow-up showed no residual mitral regurgitation more than grade I in all redo mitral valve repairs and no paravalvular leak post-valve replacement.

CONCLUSIONS

Redo-PAS-PAS is our routine approach and we apply this strategy in the majority of patients who had previous port access surgery. The predicted procedure-related mortality, morbidities, patient satisfaction and long-term outcomes are favourable.