Comparison of hemodynamics in biological surgical aortic valve replacement and transcatheter aortic valve implantation: An in-silico study.

OBJECTIVES: In aortic valve replacement (AVR), the treatment strategy as well as the model and size of the implanted prosthesis have a major impact on the postoperative hemodynamics and thus on the clinical outcome. Preinterventional prediction of the hemodynamics could support the treatment decision. Therefore, we performed paired virtual treatment with transcatheter AVR (TAVI) and biological surgical AVR (SAVR) and compared hemodynamic outcomes using numerical simulations. METHODS: 10 patients with severe aortic stenosis (AS) undergoing TAVI were virtually treated with both biological SAVR and TAVI to compare post-interventional hemodynamics using numerical simulations of peak-systolic flow. Virtual treatment procedure was done using an in-house developed tool based on position-based dynamics methodology, which was applied to the patient's anatomy including LVOT, aortic root and aorta. Geometries were automatically segmented from dynamic CT-scans and patient-specific flow rates were calculated by volumetric analysis of the left ventricle. Hemodynamics were assessed using the STAR CCM+ software by solving the RANS equations. RESULTS: Virtual treatment with TAVI resulted in realistic hemodynamics comparable to echocardiographic measurements (median difference in transvalvular pressure gradient [TPG]: -0.33 mm Hg). Virtual TAVI and SAVR showed similar hemodynamic functions with a mean TPG with standard deviation of 8.45 ± 4.60 mm Hg in TAVI and 6.66 ± 3.79 mm Hg in SAVR (p = 0.03) while max. Wall shear stress being 12.6 ± 4.59 vs. 10.2 ± 4.42 Pa (p = 0.001). CONCLUSIONS: Using the presented method for virtual treatment of AS, we were able to reliably predict post-interventional hemodynamics. TAVI and SAVR show similar hemodynamics in a pairwise comparison.

Virtual reality in cardiac interventions-New tools or new toys?

Improvementsin medical imaging and a steady increase in computing power are leading to new possibilities in the field of cardiovascular interventions. Interventions can be planned in advance in greater detail, even to the point of simulating procedures. Nevertheless, all techniques are at an early stage of development. It is of utmost importance that tools, especially if they can be used as decision support are intensively validated and their accuracy is demonstrated. In our commentary, we summarize current techniques for impprovements in planning and guiding of procedures, but also critically discuss the downsides of these techniques. Following the work of Kenichi and colleagues, we also discuss necessary steps in advancing new tools and techniques, particularly as they are used in routine clinical practice. We also discuss the role of artificial intelligence, which could play a crucial role in this context in the future.

Partial ring annuloplasty in the management of mitral annular calcification.

Mitral annular calcification (MAC) complicates the management of mitral valve (MV) disease, regardless of its etiology. Strategies to address MV surgery in MAC include two main options with their own pros and cons; respect and resect strategy. Here, we present a case of minimally-invasive MV repair with partial annuloplasty in the management of noncircumferential MAC with respect to strategy. This technique may be an alternative option for rescuing high-risk patients without extensive decalcification.

Transcatheter mitral valve implantation in the ongoing structural heart revolution.

Transcatheter mitral valve implantation (TMVI) has emerged as a less invasive approach potentially surmounting some of the current hurdles associated with transcatheter edge-to-edge repair and high-risk mitral valve surgery. In this review, we aimed to outline the main scenarios in the TMVI field, highlight current and upcoming devices, and describe challenges and clinical results. Finally, we briefly discuss the future perspectives for this emerging field and how TMVI might further advance the field of transcatheter treatments of mitral valve disease.

Right Antero-Lateral Mini-Thoracotomy Surgical Aortic Valve Replacement.

Over the past few decades, the field of minimally invasive cardiac surgery has significantly broadened. Novel surgical and endovascular techniques have been developed for the treatment of aortic valve pathologies. Surgical aortic valve replacement (SAVR) through a right antero-lateral (mini-)thoracotomy (RALT) has gained approval due to its limited postoperative trauma, faster rehabilitation and sufficient pain control. Nevertheless, SAVR RALT has not been adopted by a significant proportion of cardiac surgeons, due, in part, to its technical complexity and steep learning curve. In this review, we discuss the data for minimally invasive aortic valve surgery and describe our operative technique for SAVR RALT.

Minithoracotomy versus full sternotomy for isolated aortic valve replacement: Propensity matched data from two centers.

BACKGROUND: Minimally invasive approaches to isolated aortic valve replacement (AVR) continue to gain popularity. This study compares outcomes of AVR through right anterolateral thoracotomy (RALT) to those of AVR through full median sternotomy (MS). METHODS: Outcomes of two propensity-matched groups of 85 each, out of 250 patients that underwent isolated AVR through RALT or MS at our two institutions, were compared in a retrospective study. RESULTS: Propensity score matching resulted in 85 matched pairs with balanced preoperative characteristics. Procedure times were significantly shorter in the RALT group (median difference: 13 min [-25 to -0.5]; p = .039), cardiopulmonary bypass times were longer (median difference: 17 min [10-23.5]; p = < .001) and ventilation times shorter (median difference: 259 min [-390 to -122.5]; p = < .001). There was no significant difference in aortic cross-clamp times (median difference: 1.5 min [-3.5 to 6.5]; p = .573). The RALT group had lower rates of perioperative platelet transfusions (odds ratio [OR] = 0.00 [0.00-0.59]; p = .0078) and postoperative pneumonia (OR = 0.10 [0.00-0.70]; p = .012), as well as shorter hospitalization times (median difference: 2.5 days [-4.5 to -1]; p = .005). There were no significant differences regarding paravalvular leakage (p = .25), postoperative stroke (p = 1), postoperative atrial fibrillation (p = .12) or 1-year-mortality (p = 1). CONCLUSIONS: This study found RALT to be an equally safe approach to surgical AVR as MS. Furthermore, RALT showed advantages regarding important aspects of postoperative recovery, especially concerning pulmonary function.

State of the Art Review: Surgical Treatment of Acute Type A Aortic Dissection.

Acute type A aortic dissection (ATAAD) is a life-threatening event that requires immediate surgical treatment. Improvements in surgical treatment, graft technology, organ protection and imaging techniques have led to improved clinical outcomes. Individualized treatment concepts have emerged based on more advanced planning tools that allow for a tailored approach even in complex situations such as multi-level malperfusion. This review provides an overview of the current surgical treatment of ATAAD, focusing on new disease classifications, preoperative computed tomography angiography (CTA) assessment, new prosthesis and stent technologies, and organ-protection strategies.

Control of ventricular unloading using an electrocardiogram-synchronized pulsatile ventricular assist device under high stroke ratios.

Pulsatile ventricular assist devices (pVADs) yield a blood flow that imitates the pulsatile flow of the heart and, therefore, could diminish the adverse events related to the continuous flow provided by the ventricular assist devices that are commonly used. However, their intrinsic characteristics of larger size and higher weight set a burden to their implantation, that along with the frequent mechanical failures and thrombosis events, reduce the usage of pVADs in the clinical environment. In this study, we investigated the possibility to reduce the pump size by using high pump stroke ratios while maintaining the ability to control the hemodynamics of the cardiovascular system (CVS). In vitro and in vivo experiments were conducted with a custom pVAD implemented on a hybrid mock circulation system and in five sheep, respectively. The actuation of the pVAD was synchronized with the heartbeat. Variations of the pump stroke ratio, time delay between the pump stroke and the heart stroke, as well as duration of the pump systole in respect to the total cardiac cycle duration were used to evaluate the effects of various pump settings on the hemodynamics of the CVS. The results suggest that by varying the operating settings of the pVAD, a pulsatile flow that provides physiological hemodynamic parameters, as well as a control over the hemodynamic parameters, can be achieved. Additionally, by employing high pump stroke ratios, the size of the pVAD can be significantly reduced; however, at those high pump stroke ratios, the effect of the other pump parameters diminishes.

Body donation as a grateful gift for a long and active life with a Björk-Shiley valve.

An 87-year-old patient donated his body to the Institute of Anatomy and Cell Biology in gratefulness for the longevity of a Björk-Shiley convexo-concave (BSCC) prosthetic aortic valve, implanted 34 years ago. The dissection of the enlarged heart showed no major signs of thrombosis, malignant fibrosis, or any other relevant issue that could potentially lead to valve failure as in other patients. Despite the reported high mortality rate of the earlier designs, especially of the BSCC valves, some patients survived for longer than expected. In more than 34 years after the BSCC valve implantation, the patient was a very active and lively man, working both as full-time and volunteer firefighter. The lifespan of this BSCC valve is among the longest reported.

Surgical explantation of a partially detached cardioband device.

Transcatheter repair systems are becoming increasingly popular as a potential solution for high-risk and inoperable patients with mitral regurgitation. The cardioband (Edwards Lifesciences, Irvine, California) is a transcatheter direct annuloplasty device, based on the concept of an undersized ring annuloplasty. We report a case of minimally invasive surgical explantation of a failed cardioband device 21 months after its implantation. Intraoperatively, it was found that three anchors of the cardioband device were detached from the posterior annulus at P2. In this report, a "cut and unscrew" technique with some tips and tricks is presented for the removal of the device.

Transcatheter aortic valve implantation and its impact on mitral valve geometry and function.

BACKGROUND: The aim of this study was to evaluate the impact of transcatheter aortic valve implantation (TAVI) on mitral valve geometry and function. METHODS: Eighty-four patients underwent TAVI. Forty-four (52%) patients received a balloon-expandable valve and 40 (48%) were implanted with a self-expandable valve. All patients underwent three-dimensional-volumetric transesophageal echocardiography of the mitral valve before and immediately after TAVI. A dedicated software was used for assisted semiautomatic measurement of mitral annular geometry. RESULTS: During systole, the anterior to posterior (AP) diameter was significantly reduced after the procedure (3.4 ± 0.5 cm vs 3.2 ± 0.5 cm; P < .05). The mitral annular area (10.8 ± 2.8cm2 vs 9.9 ± 2.6cm2 ; P < .05) as well as the tenting area (1.6 ± 0.7 cm2 vs 1.2 ± 0.6 cm2 ; P < .001) measured at mid-systole were reduced after TAVI. Diastolic measures were similar. Patients treated with balloon-expandable valves showed a significantly larger reduction in the AP diameter compared to self-expandable valves (-0.25 cm vs -0.11 cm; P < .05). The reduction of the annular area was higher in the balloon-expandable group (-1.2 ± 1.59 vs -0.22 ± 1.41; P < .05). Grade of mitral regurgitation did improve or remained stable after TAVI. CONCLUSION: TAVI significantly impacts the mitral valve and mitral annular geometry and morphology. The choice of the prosthesis (balloon- vs self-expandable) may be relevant for those changes.

Minimally invasive surgical aortic valve replacement: The RALT approach.

Less-invasive techniques for cardiothoracic surgical procedures are designed to limit surgical trauma, but the technical requirements and preoperative planning are more demanding than those for conventional sternotomy. Patient selection, interdisciplinary collaboration, and surgical skills are key factors for procedural success. Aortic valve replacement is frequently performed through an upper hemisternotomy, but the right anterior minithoracotomy represents an even less traumatic, technical advancement. Preoperative assessment of the ascending aorta in relation to the sternum is mandatory to select patients and the intercostal access site. This description of the surgical technique focuses on the specific procedural details including the obligatory planning with computed tomography and our cannulation strategy. We also sought to define the anatomical ascending aorta-sternal relationship, as it is of utmost importance in preoperative computed tomographic planning.

New Hybrid Prosthesis for Acute Type A Aortic Dissection.

BACKGROUND: Acute type A aortic dissection (ATAAD) is a surgical emergency with high rates of morbidity and mortality. The treatment of ATAAD is highly individualized and mainly depends on anatomical and technical factors. Great efforts to reduce the time to diagnosis and technological innovations have led to improved surgical results with a lower rate of dissection-related reoperations during long-term follow up. The aim of this article is to introduce a novel hybrid device for the treatment of DeBakey I acute aortic dissection. CONCEPT: A non-covered hybrid stent from Ascyrus Medical (Boca Raton, FL, USA) aims to improve the current standard of care, without increasing technical complexity or device-related complications. The AMDS (Ascyrus Medical Dissection Stent) prolongs the hemiarch operation by only a few minutes, does not need endovascular skills to be deployed, and provides an anatomical and "haemodynamic" correction. The device is intended to reduce perfusion of the false lumen by sealing the distal anastomosis, and to restore distal perfusion of the true lumen. Obliteration of the false lumen at the distal anastomosis is likely to reduce aortic enlargement and the need for reoperations, mainly driven by a low-flow state and pressure reduction, which promote thrombosis. CONCLUSIONS: The AMDS provides a new concept to treat acute aortic dissection by moving the focus from resecting the dissected tissue to restoring adequate true-lumen flow and sealing the false lumen at the distal anastomosis. With a high rate of procedural success, AMDS represents a safe, reproducible and promising solution to treat DeBakey I aortic dissections.

Sternal Anomalies in Asymptomatic Patients after Median Sternotomy and Potential Influencing Factors.

BACKGROUND: We aimed to assess asymptomatic patients who had open-heart surgery with median sternotomy for potential sternal anomalies (SA), their related patient-specific risk factors, and treatment options for the prevention of SA. METHODS: Multiplanar CT scans (CTs) from 131 asymptomatic consecutive patients were analyzed retrospectively. Of these, 83 underwent CABG (63.4%), and 48 had aortic valve (AV) procedures via median sternotomy. Sternal bone healing was analyzed for SA and their exact location. RESULTS: In total, 49 SA were identified in 42 (32.1%) patients; 65% SA were found in the manubrium (n = 32). Five hundred thirty-two wires were implanted (4.2 ± 0.5 wires/patient), out of which 96.1% (n = 511) were figure 8 wires. There was no difference between normal and abnormal sterna with regard to the number of wires used for sternal closure (4.2 ± 0.5 vs. 4.3 ± 0.6, p = ns). The distance between wire placement to the proximal edge of the manubrium in normal and abnormal sterna was comparable (11.2 ± 4.2 vs. 10.9 ± 4.8 mm, p = ns). Patients who underwent CABG had a significantly higher risk for SA (OR = 2.4, p ≤ 0.05, 95% CI [1.2-4.9]). The use of BIMA (OR = 4.4, p ≤ 0.05, 95% CI [1.1-17.9]) and body mass index (BMI) > 31 kg/m2 (OR = 3.4, p ≤ 0.01, 95% CI [1.4-8.3]) significantly increased the risk of SA. CONCLUSION: At least 30% of patients were at an increased risk for SA after receiving a median sternotomy. CABG, use of BIMA, and a BMI > 30 kg/m2 were potential risk factors for the development of SA and warrant close clinical follow-up. Sternal plate fixation, particularly in the manubrium, could be beneficial in such patients.

Results of mitral valve repair with an adjustable annuloplasty ring 2 years after implantation.

We aimed to investigate the safety and medium-term durability of an adjustable mitral annuloplasty ring in patients undergoing surgery for mitral valve regurgitation. Forty-five patients requiring mitral valve repair were enrolled into this prospective, multicentre study between May 2012 and May 2013 in six hospitals in Europe and Israel. Study endpoints evaluated the performance and safety of the device assessed using inter-individual comparisons. Implantation was performed through a sternotomy in ten patients and mini-thoracotomy in 35 patients. The ring was adjusted after declamping and weaning from cardio-pulmonary bypass under echocardiographic guidance if the coaptation surface was not optimal, or in cases of residual mitral regurgitation. Follow-up was performed up to 2 years post-procedure. Mean age was 61 ± 12 years. Ring adjustment was performed in 71% of patients to optimise the results of mitral valve repair. Following the procedure, 11/45 patients (24%) who had had mild residual mitral regurgitation had no mitral regurgitation following ring adjustment. Two patients with severe mitral regurgitation post-procedure had mild regurgitation following ring adjustment. Coaptation length increased significantly after adjustment. One patient died before hospital discharge due to complications unrelated to the adjustable ring. One patient had to undergo re-operation at 39 days post-procedure due to endocarditis. At 2 years of follow-up, 78% of patients had no residual mitral regurgitation and 22% had mild residual mitral regurgitation. Adjustable mitral annuloplasty ring implantation was safe in all patients. Mitral valve repair with the adjustable ring was durable in all patients who reached 2 years follow-up. CLINICAL TRIAL REGISTRATION: NCT01617720.

Use of extracellular matrix patches in cardiac surgery.

A noncellular xenogeneic extracellular matrix derived from the porcine small intestinal submucosa can be used as a new patch material with potential advantages. We review the literature on the use of this material in cardiac surgery.

Use of extracellular matrix materials in patients with endocarditis.

Tissue replacement is sometimes necessary during surgery for endocarditis. Commonly used materials are Dacron, expanded polytetrafluoroethlyene, or bovine pericardium. Those materials have no potential for bioresorption and cannot restore regional functionality. Extracellular matrices became available lately as patch material. Here we present two cases of patients with endocarditis. CorMatrix ECM (CorMatrix Cardiovascular, Inc., Atlanta, Georgia, United States) was used to repair intracardiac structures with good results in follow-up up to 3 months. CorMatrix ECM may be an adequate alternative to foreign material for patients with endocarditis.

Experience with a "hotline" service for outpatients on a ventricular assist device.

OBJECTIVES: With the growing number of outpatients on ventricular assist devices (VADs), there is an increasing need for "home discharge programs." One important feature is a 24-hour telephone service. In our center, the perfusionists run a so-called "hotline" for all of our VAD patients. This study analyzes the hotline calls with regard to frequency, the reason for calling, and the type of action undertaken. PATIENTS AND METHODS: Over a period of 5 years, 16 (12 EXCOR and 4 INCOR; Berlin Heart, Berlin, Germany) of 33 VAD patients (48%) were discharged and instructed to use the "hotline" service. All the calls received by the perfusionists were reviewed. We classified the calls into three levels according to the severity of the problem: Level (L) 1 = assistance provided by the perfusionist alone; L2 = calls requiring discussion with the surgeon on duty and/or visit to the outpatient clinic ahead of time; and L3 = immediate action and/or admission to the hospital. RESULTS: Over a period of 2,890 outpatient days (7.9 years), a total of 26 calls were registered. There were 0.9 calls per 100 patient days and 1.6 calls per discharged patient. Out of the 26 calls, 14 calls (54%) were classified as L1, 8 (31%) as L2, and 4 (15%) as L3. The most frequent reasons for L1 or L2 calls were fibrin deposits in the EXCOR pump chamber (39%), followed by battery dysfunction (19%). L3 calls were related to dysfunction of the EXCOR driving units in three cases and to an EXCOR pump chamber disconnection, which the patient did not survive. CONCLUSIONS: The institution of a hotline is an essential component of a VAD outpatient program. It provides a certain level of safety for the patient, although a residual risk remains.

The role of concomitant coronary artery bypass grafting in acute type A aortic dissection complicated by coronary malperfusion.

OBJECTIVES: Managing acute type A aortic dissection with coronary malperfusion is challenging. This study outlines our revascularization strategy for these patients. METHODS: Patients undergoing surgery for acute type A aortic dissection with coronary malperfusion and aortic root involvement from January 2000 to December 2021 were included. Patients were classified using the Neri classification for coronary dissection, including a novel 'Neri -' class (no coronary dissection). Patients undergoing revascularization either as a planned or as a bailout strategy due to persisting low cardiac output were compared additionally. RESULTS: The cohort comprised 195 patients: 43 (22%) Neri -, 43 (22%) Neri A, 74 (38%) Neri B and 35 (18%) Neri C. Aortic root replacement was mainly performed in 25 Neri C patients (71%; P < 0.001). Concomitant bypass surgery was performed in 4 (9%) of Neri -, 5 (12%) of Neri A, 21 (28%) of Neri B and 32 (91%) of Neri C patients (P < 0.001). Thirty-day mortality was 42% with 21 (49%) Neri -, 12 (28%) Neri A, 30 (41%) Neri B and 19 (54%) Neri C patients (P = 0.087). Bailout revascularization was primarily performed in 11 Neri B patients (69%; P = 0.001) and associated with a higher 30-day mortality of 81% compared to 48% for planned revascularization (P = 0.042). CONCLUSIONS: Postoperative outcomes in case of coronary malperfusion are poor, irrespective of the anatomic dissection pattern. The decision for concomitant bypass surgery is crucial but may be considered in Neri C patients combined with aortic root replacement. Bailout revascularization was most common in Neri B and showed dismal outcome.

A simulation-based phantom model for generating synthetic mitral valve image data-application to MRI acquisition planning.

PURPOSE: Numerical phantom methods are widely used in the development of medical imaging methods. They enable quantitative evaluation and direct comparison with controlled and known ground truth information. Cardiac magnetic resonance has the potential for a comprehensive evaluation of the mitral valve (MV). The goal of this work is the development of a numerical simulation framework that supports the investigation of MRI imaging strategies for the mitral valve. METHODS: We present a pipeline for synthetic image generation based on the combination of individual anatomical 3D models with a position-based dynamics simulation of the mitral valve closure. The corresponding images are generated using modality-specific intensity models and spatiotemporal sampling concepts. We test the applicability in the context of MRI imaging strategies for the assessment of the mitral valve. Synthetic images are generated with different strategies regarding image orientation (SAX and rLAX) and spatial sampling density. RESULTS: The suitability of the imaging strategy is evaluated by comparing MV segmentations against ground truth annotations. The generated synthetic images were compared to ones acquired with similar parameters, and the result is promising. The quantitative analysis of annotation results suggests that the rLAX sampling strategy is preferable for MV assessment, reaching accuracy values that are comparable to or even outperform literature values. CONCLUSION: The proposed approach provides a valuable tool for the evaluation and optimization of cardiac valve image acquisition. Its application to the use case identifies the radial image sampling strategy as the most suitable for MV assessment through MRI.