Alternative minimally invasive surgical explantation techniques for failed transcatheter mitral valve repair devices

Objective

The use of transcatheter mitral valve repair (TMVr) devices is increasing in elderly and high-risk patients. However, the increasing number of patients with recurrent mitral regurgitation (MR) has confronted surgeons with the issue of how to explant the devices and whether the mitral valve should be repaired or replaced. The aim of the study is to summarize our clinical experience with the explantation of different TMVr devices and to provide alternative surgical techniques that can be performed in different clinical scenarios.

Methods

A simulator system including a dummy valve representing native valves was used to create video documentation and to develop alternative surgical methods for clip explantation. Moreover, the clip explantation techniques were shown in 2 patients undergoing minimally-invasive mitral valve repair after a failed TMVr.

Results

Alternative explantation techniques were described for each TMVr device; 2 techniques for MitraClip and 3 techniques for PASCAL (Precision Transcatheter Valve Repair System), which may be adjusted for each individual according to the underlying valve pathology and the degree of device encapsulation. The patients were discharged without residual MR and remained MR free at the follow-up.

Conclusions

Transcatheter edge-to-edge repair devices can be surgically explanted without damaging the MV leaflets. Removal of each device may require a different technique tailored to the degree of device encapsulation and valve pathology. Increasing experience may facilitate repair in patients with recurrent MR after TMVr.

Image-based ring size prediction for mitral valve repair

OBJECTIVES

Annuloplasty rings are routinely used in mitral valve repair (MVr). However, accurate annuloplasty ring size selection is essential to obtain a favorable outcome. Moreover, ring sizing can be challenging in some patients and is highly influenced by surgeons' experience. This study investigated the utility of three-dimensional mitral valve (3D-MV) reconstruction models to predict annuloplasty ring size for MVr.

METHODS

A total of 150 patients undergoing minimally invasive MVr with annuloplasty ring due to Carpentier type II pathology and who were discharged with none/trace residual MR were included. 3D-MV reconstruction models were created with a semi-automated software package (4D MV Analysis; Tomtec Imaging Systems, Munich, Germany) to quantitate MV geometry. To predict the ring size, univariable and multivariable linear regression analyses were performed.

RESULTS

Between 3D-MV reconstruction values and implanted ring sizes, the highest correlation coefficients were provided by commissural width (CW) (0.839; p < 0.001), intertrigonal distance (ITD) (0.796; p < 0.001), annulus area (0.782; p < 0.001), anterior mitral leaflet area (0.767; p < 0.001), Anterior-posterior diameter (0.679; p < 0.001) and AML length (0.515; p < 0.001). In multivariable regression analysis, only CW and ITD were found to be independent predictors of annuloplasty ring size (R2=0.743; p < 0.001). The highest level of agreement was achieved with CW and ITD, and 76.6% of patients received a ring with no greater than one ring size difference from the predicted ring sizes.

CONCLUSIONS

3D-MV reconstruction models can support surgeons in the decision-making process for annuloplasty ring sizing. The present study may be a first step towards accurate annuloplasty ring size prediction using multimodal Machine Learning decision support.

Minimally Invasive Extirpation of Benign Atrial Cardiac Tumors: Clinical Follow-Up and Survival

OBJECTIVE

Evidence determining the optimal treatment for cardiac tumors is rare. We report our midterm clinical outcome and patient characteristics of our series undergoing atrial tumor removal through a right lateral minithoracotomy (RLMT).

METHODS

From 2015 to 2021, 51 patients underwent RLMT for atrial tumor extirpation. Patients receiving concomitant atrioventricular valvular, cryoablation, and/or patent foramen ovale closure surgery were included. Follow-up was performed using standardized questionnaires (mean: 1,041 ± 666 days). Follow-up involved any tumor recurrence, clinical symptoms, and any recurrent arterial embolization. Survival analysis was successfully achieved in all patients.

RESULTS

Successful surgical resection was achieved in all patients. Mean cardiopulmonary bypass and cross-clamping times were 75 ± 36 and 41 ± 22 min, respectively. The most common tumor location was the left atrium (n = 42, 82.4%). Mean ventilation time was 12.74 ± 17.23 h, intensive care unit stay ranged from 1 to 1.9 days (median: 1 day). Nineteen patients (37.3%) received concomitant surgery. Histopathological analysis showed 38 myxoma (74.5%), 9 papillary fibroelastoma (17.6%), and 4 thrombus (7.8%). Thirty-day mortality was observed in 1 case (2%). One patient (2%) suffered a stroke postoperatively. No patient had a relapse of cardiac tumor. Three patients (9.7%) showed arterial embolization during follow-up. Thirteen follow-up patients (25.5%) were in New York Heart Association class ≤II. Overall survival was 90.2% at 2 years.

CONCLUSIONS

A minimally invasive approach for benign atrial tumor resection is effective, safe, and reproducible. Of the atrial tumors, 74.5% were myxoma and 82% were located in the left atrium. A low 30-day mortality rate with no manifestation of recurrent intracardiac tumor was observed.

Single-Center Experience With a Self-Expandable Venous Cannula During Minimally Invasive Cardiac Surgery

OBJECTIVE

Venous drainage is often problematic in minimally invasive cardiac surgery (MICS). Here, we describe our experience with a self-expandable stent cannula designed to optimize venous drainage.

METHODS

The smart canula^® was used in 58 consecutive patients undergoing MICS for mitral valve disease (n = 40), left atrial myxoma (n = 3), left ventricular outflow tract obstruction (n = 1), and aortic valve replacement via a right anterior minithoracotomy (n = 14) procedures. The venous cannula was placed under transesophageal echocardiography guidance to reach the superior vena cava. Vacuum-assisted venous drainage (between -20 and -35 mm Hg) was used to reach a target flow index of 2.2 L/min/m² at a core temperature of 34 °C using a goal-directed perfusion strategy aimed at a minimum DO₂ of 272 mL/min/m². Cardiopulmonary bypass (CPB) parameters were recorded, and hemolysis-related parameters were analyzed on postoperative days 1 to 7.

RESULTS

Mean body surface area and median body mass index were 1.9 ± 0.2 m² and 25.2 (23.4, 30.2) kg/m². Mean CPB and median cross-clamping times were 107.7 ± 24.4 min and 64.5 (53, 75.8) min, and median CPB flow during cardioplegic arrest was 4 (3.6, 4.2) L/min (median cardiac index 2.1 [2, 2.2] L/min/m²). Venous drainage was considered sufficient by the surgeon in all cases, and insertion and removal were uncomplicated. Mean SvO₂ during CPB was 80.2% ± 5.5%, and median peak lactate was 10 (8, 14) mg/dL, indicating sufficient perfusion. Mean venous negative drainage pressure during cross-clamping was 27.2 ± 12.3 mm Hg. Platelets dropped by 73.6 ± 37.5 K/µL, lactate dehydrogenase rose by 81.5 (44.3, 140.8) U/L, and leukocytes rose by 3.4 (2.2, 7.2) K/µL on postoperative day 1.

CONCLUSIONS

The venous smart canula^® allows for optimal venous drainage at low negative drainage pressures, facilitating sufficient perfusion in MICS.

Factors associated with an unsuccessful Fast-Track course following Minimally Invasive Surgical Mitral Valve Repair

OBJECTIVES

Analyses of fast-track processes demonstrated that low-risk cardiac surgical patients require minimal intensive care, with a low incidence of mortality or morbidity. We investigated perioperative factors and their association with fast-track failure in a retrospective cohort study of patients undergoing minimally invasive mitral valve surgery.

METHODS

Patients undergoing minimally invasive surgical mitral valve repair for Carpentier type I or type II mitral regurgitation between 2014 and 2020 were included in the study. The definition of fast-track failure consisted of > 10 hours mechanical ventilation, >24 hours intensive care unit stay, re-intubation after extubation and re-admission to the intensive care unit. Multivariable logistic regression analysis enabled the identification of factors associated with fast-track failure.

RESULTS

In total, 491 patients were included in the study and were analysed. Two-hundred and thirty-seven patients (48.3%) failed the fast-track protocol. Multivariable logistic regression analysis showed that a New York Heart Association classification ≥3 (OR 2.05; CI 1.38-3.08; p < 0.001, pre-existing chronic kidney disease (OR 2.03; CI 1.14-3.70; p = 0.018), coronary artery disease (OR 1.90; CI 1.13-3.23; p = 0.016), postoperative bleeding requiring surgical revision (OR 8.36; CI 2.81-36.01; p < 0.001) and procedure time (OR 1.01; CI 1.01-1.01; p < 0.001) were independently associated with fast-track failure.

CONCLUSIONS

Factors associated with fast-track failure in patients with Carpentier type I and II pathologies undergoing minimally invasive mitral valve repair are a New York Heart Association classification III-IV at baseline, pre-existing chronic kidney disease and coronary artery disease. Postoperative bleeding requiring rethoracotomy and procedure time were also identified as important factors associated with failed fast-track.

CLINICAL REGISTRATION NUMBER

The corresponding local ethics committee (Charité Medical School, Berlin, Germany) approved the present study which complies with the Declaration of Helsinki (ethics approval number: EA2/175/20).

Cardiovalve in mitral valve position—Additional solution for valve replacement

We report on a 72 years old male patient with recurrent heart failure hospitalizations caused by severe mitral regurgitation due to severe restriction of the posterior mitral leaflet treated with the transfemoral mitral valve replacement (TMVR) system Cardiovalve. Immediate interventional success was obtained resulting in a quick mobilization and discharge.

Valve embolization during transcatheter aortic valve implantation: Incidence, risk factors and follow-up by computed tomography

Background

In most cases of transcatheter valve embolization and migration (TVEM), the embolized valve remains in the aorta after implantation of a second valve into the aortic root. There is little data on potential late complications such as valve thrombosis or aortic wall alterations by embolized valves.

Aims

The aim of this study was to analyze the incidence of TVEM in a large cohort of patients undergoing transcatheter aortic valve implantation (TAVI) and to examine embolized valves by computed tomography (CT) late after TAVI.

Methods

The patient database of our center was screened for cases of TVEM between July 2009 and July 2021. To identify risk factors, TVEM cases were compared to a cohort of 200 consecutive TAVI cases. Out of 35 surviving TVEM patients, ten patients underwent follow-up by echocardiography and CT.

Results

54 TVEM occurred in 3757 TAVI procedures, 46 cases were managed percutaneously. Horizontal aorta (odds ratio [OR] 7.51, 95% confidence interval [CI] 3.4–16.6, p < 0.001), implantation of a self-expanding valve (OR 4.63, 95% CI 2.2–9.7, p < 0.01) and a left ventricular ejection fraction < 40% (OR 2.94, 95% CI 1.1–7.3, p = 0.016) were identified as risk factors for TVEM. CT scans were performed on average 26.3 months after TAVI (range 2–84 months) and detected hypoattenuated leaflet thickening (HALT) in two patients as well as parts of the stent frame protruding into the aortic wall in three patients.

Conclusion

TVEM represents a rare complication of TAVI. Follow up-CT detected no pathological findings requiring intervention.

The Arch Remodeling Stent for DeBakey I Acute Aortic Dissection: Experience with 100 Implantations

OBJECTIVES

A novel hybrid non-covered stent was developed to treat malperfusion and prevent aneurysm formation following hemiarch procedure for DeBakey I acute aortic dissection (AAD). The present analysis investigates the performance of the device in 100 consecutive implantations.

METHODS

Between 2018 and 2021, 100 patients underwent surgical repair of DeBakey I AAD with implantation of a non-covered stent in the arch and descending aorta. The primary entry tear was located in the root or in the ascending aorta. Clinical and imaging data were collected and analyzed retrospectively. Endpoints of the study were 30-day mortality, neurologic outcome and need of additional procedures due to postoperative malperfusion. Technical success was assessed in the first post-operative computed tomography in regard to the induction of false lumen thrombosis in the descending aorta.

RESULTS

Median age was 61 [54-73] years. Preoperative malperfusion was present in 46 (46%) patients. Primary arterial cannulation strategy was the right axillary artery and an open distal anastomosis was performed in a median caudal circulatory arrest of 40 [34-52] minutes. In 48% of cases, a 55-40 tapered stent was implanted. The 30-day mortality was 18%, an operation-related new postoperative neurologic deficit was present in 8%. Technical success was achieved in 76% of patients.

CONCLUSIONS

The novel non-covered stent can be safely applied to complement aortic repair with the hemiarch procedure for DeBakey I AAD. The expansion of the true lumen through the device may prevent postoperative malperfusion and induces positive vascular remodeling with thrombosis of false lumen.

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.

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.

Aortic valve replacement via right anterolateral minithoracotomy: preventing adverse events during the initial learning curve

BACKGROUND

Despite excellent outcomes and reduced invasiveness, the right anterolateral thoracotomy approach for aortic valve replacement (RALT-AVR) has not been broadly adopted. This study provides results regarding the initial experience and learning curve of a single surgeon performing this procedure.

METHODS

Periprocedural details and postoperative outcomes of the first 100 consecutive patients who underwent RALT-AVR at our institution were retrospectively analyzed. We conducted a cumulative sum analysis of surgical failure, defined as occurrence of 30-day-mortality, surgical revision for bleeding, conversion to sternotomy, 3^rd degree heart block, paravalvular leakage, postoperative stroke or mean transvalvular gradient >20 mmHg.

RESULTS

The cohort was of low surgical risk (mean EuroSCORE II 1.31%±0.85, mean STS PROM 1.45%±0.97), 58% were males. Median cross-clamp time was 67.5 (57.8-76) min, median CPB time 105 (91.8-119) min, and median operation time 164.5 (144.5-183.2) min. There were no conversions to full sternotomy, 4 cases of revision for bleeding and 2 pacemaker implantations for 3^rd degree heart block. Prosthesis function was good (median ΔPmean 10.9 [7.4-13.6] mmHg). Thirty-day-mortality was 0%. The log-likelihood graph never crossed the upper boundary, and after a steady decrease, crossed the lower boundary at 93 patients.

CONCLUSIONS

RALT-AVR can be performed with acceptable procedural times and satisfactory outcomes. For a well-trained surgeon, adapting to this new procedure does not expose patients to an increased risk, when patient selection and procedural planning are applied appropriately. Cumulative sum failure analysis is an appropriate tool to monitor the transition from standard AVR to the technically more demanding RALT-AVR.

Comparison of feasibility and results of frailty assessment methods prior to left ventricular assist device implantation

AIMS

Assessing frailty and sarcopenia is considered a valuable cornerstone of perioperative risk stratification in advanced heart failure patients. The lack of an international consensus on a diagnostic standard impedes its implementation in the clinical routine. This study aimed to compare the feasibility and prognostic impact of different assessment tools in patients undergoing continuous-flow left ventricular assist device (cf-LVAD) implantation.

METHODS AND RESULTS

We prospectively compared feasibility and prognostic values of six frailty/sarcopenia assessment methods in 94 patients prior to cf-LVAD implantation: bioelectrical impedance analysis (BIA), computed tomography (CT)-based measurement of two muscle areas/body surface area [erector spinae muscle (TMESA/BSA) and iliopsoas muscle (TPA/BSA)], physical performance tests [grip strength, 6 min walk test (6MWT)] and Rockwood Clinical Frailty Scale (RCFS). Six-month mortality and/or prolonged ventilation time >95 h was defined as the primary endpoint. BIA and CT showed full feasibility (100%); physical performance and RCFS was limited due to patients' clinical status (feasibility: 87% grip strength, 62% 6MWT, 88% RCFS). Phase angle derived by BIA showed the best results regarding the prognostic value for 6 month mortality and/or prolonged ventilation time >95 h (odds ratio (OR) 0.66 [95% confidence interval (CI): 0.46-0.92], P = 0.019; area under the curve (AUC) 0.65). It provided incremental value to the clinical risk assessment of EuroSCORE II: C-index of the combined model was 0.75 [95% CI; 0.651-0.848] compared with C-index of EuroSCORE II alone, which was 0.73 (95% CI: 0.633-0.835). Six-month survival was decreased in patients with reduced body cell mass derived by BIA or reduced muscle area in the CT scan compared with patients with normal values: body cell mass 65% (95% CI: 51.8-81.6%) vs. 83% (95% CI: 74.0-93.9%); P = 0.03, TMESA/BSA 65% (95% CI: 51.2-82.2%) vs. 82% (95% CI: 73.2-93.0%); P = 0.032 and TPA/BSA 66% (95% CI: 53.7-81.0%) vs. 85% (95% CI: 75.0-95.8%); P = 0.035.

CONCLUSIONS

Bioelectrical impedance analysis parameters and CT measurements were shown to be suitable to predict 6-month mortality and/or prolonged ventilation time >95 h in patients with advanced heart failure prior to cf-LVAD implantation. Phase angle had the best predictive capacity and sarcopenia diagnosed by reduced body cell mass in BIA or muscle area in CT was associated with a decreased 6 month survival.

The Pandora's Box of Frailty Assessments: Which Is the Best for Clinical Purposes in TAVI Patients? A Critical Review

Frailty assessment is recommended before elective transcatheter aortic valve implantation (TAVI) to determine post-interventional prognosis. Several studies have investigated frailty in TAVI-patients using numerous assessments; however, it remains unclear which is the most appropriate tool for clinical practice. Therefore, we evaluate which frailty assessment is mainly used and meaningful for ≤30-day and ≥1-year prognosis in TAVI patients. Randomized controlled or observational studies (prospective/retrospective) investigating all-cause mortality in older (≥70 years) TAVI patients were identified (PubMed; May 2020). In total, 79 studies investigating frailty with 49 different assessments were included. As single markers of frailty, mostly gait speed (23 studies) and serum albumin (16 studies) were used. Higher risk of 1-year mortality was predicted by slower gait speed (highest Hazard Ratios (HR): 14.71; 95% confidence interval (CI) 6.50–33.30) and lower serum albumin level (highest HR: 3.12; 95% CI 1.80–5.42). Composite indices (five items; seven studies) were associated with 30-day (highest Odds Ratio (OR): 15.30; 95% CI 2.71–86.10) and 1-year mortality (highest OR: 2.75; 95% CI 1.55–4.87). In conclusion, single markers of frailty, in particular gait speed, were widely used to predict 1-year mortality. Composite indices were appropriate, as well as a comprehensive assessment of frailty.

SLL-PEEP Ventilation to Improve Exposure in Minimally Invasive Right Anterolateral Minithoracotomy Aortic Valve Replacement

OBJECTIVE

An accepted landmark to assess feasibility of surgical aortic valve replacement (SAVR) via right anterolateral minithoracotomy (RALT) is the aortic-midpoint to right-sternal-edge distance. We aimed to evaluate single left lung positive-end-expiratory-pressure (SLL-PEEP) ventilation inducing an intraoperative rightward shift of the ascending aorta to improve exposure.

METHODS

Nineteen patients with aortic stenosis undergoing SAVR via RALT were prospectively analyzed. SLL-PEEP ventilation (20,395 cmH₂O) via a double-lumen endotracheal tube was applied immediately before transthoracic aortic cross-clamping, thereby inducing rightward shift of the ascending aorta to enhance exposure. We analyzed preoperative computed tomography (CT) reconstructions and intraoperative video recordings. Primary endpoint was extent of rightward shift induced by SLL-PEEP ventilation; secondary endpoints were procedure times and safety events.

RESULTS

Mean age was 61 ± 14.8 years and 6 of 19 (31.6%) were female. Mean EuroSCORE II was 0.81% ± 0.04%, STS-PROM was 1.13% ± 0.74%, and mean aortic rightward shift induced by SLL-PEEP ventilation was 10.32 ± 4.14 mm (4 to 17 mm; P = 0.003). Median shift in the group considered suitable for the RALT approach by preoperative CT-scan evaluation was 14.2 mm (IQR 11) and in the less suitable group 11.5 mm (IQR 5). Mean procedure time was 167 ± 28.9 min, CPB time was 105.7 ± 18.4 min, and cross-clamp time was 64.5 ± 13 min. Fifteen patients (79%) received SAVR via RALT with implantation of a bioprosthesis, whereas a rapid-deployment-prosthesis was used in 4 patients (21%). Ten of 19 (53%) patients who were classified as less suitable preoperatively received SAVR via RALT after SLL-PEEP ventilation. No strokes were observed.

CONCLUSIONS

The SLL-PEEP ventilation maneuver during SAVR via RALT significantly enhances aortic exposure. There were no safety events associated with this maneuver and we were able to demonstrate significant rightward aortic shift in every single patient.

Mitral valve surgery: current status and future prospects of the minimally invasive approach

Introduction: During the past five years the approach to procedural planning, operative techniques and perfusion strategies for minimally invasive mitral valve surgery (MIMVS) has evolved. With the goal to provide a maximum of patient safety the procedure has been modified according to individual patient characteristics and is largely based on preoperative imaging.Areas covered: In this review article we describe the important factors in image based therapy planning and simulation, different access strategies, the operative key-steps, a rationale use of devices, and highlight a few future developments in the field of MIMVS. Published studies were identified through pearl growing, citation chasing, a search of PubMed using the systematic review methods filter, and the authors' topic knowledge.Expert opinion: With the help of expert teams including surgeons specialized in mitral repair, anesthesiologists and perfusionists a broad spectrum of mitral valve pathologies and related pathologies can be treated with excellent functional outcomes. Avoiding procedure related complications is the key for success for any MIMVS program.

Experience with a standardized protocol to predict successful explantation of left ventricular assist devices

OBJECTIVE

Patients with a continuous-flow left ventricular assist device may show recovery of myocardial function with unloading. Identifying candidates for and predicting clinical and hemodynamic stability after left ventricular assist device explantation remain challenging.

METHODS

Retrospective analysis of patients who underwent evaluation for left ventricular assist device explantation following a standardized protocol from January 2016 to March 2020. Patients who met screening criteria underwent echocardiography under "baseline," "minimal net flow," and "pump stop" conditions. If the protocol criteria were met, right heart catheterization with left ventricular assist device stoppage and occlusion of the outflow graft with a balloon catheter were performed. In patients with pulmonary capillary wedge pressure less than 16 mm Hg, explantation was performed under "pump stop" conditions.

RESULTS

A total of 544 patients were screened. Of these, 57 (10.5%) underwent a total of 73 echocardiography under "baseline" "minimal net flow" and "pump stop" conditions and 46 underwent left ventricular assist device stoppage and occlusion of the outflow graft with balloon catheter maneuvers. Complications during the procedure were rare. Ultimately, 21 patients (3.9%) underwent explantation. The left ventricular ejection fraction at baseline was 55.5% ± 6.5%. The mean pulmonary capillary wedge pressure was 8.1 ± 2.6 mm Hg and increased to 10.7 ± 2.9 mm Hg under left ventricular assist device stoppage and occlusion of the outflow graft with a balloon catheter. A nonischemic cause of cardiomyopathy was more likely to be found in patients who underwent explantation (20/21 patients [95%], P = .020). The survival 1 year after explantation was 95.2%, with 1 death occurring 222 days after left ventricular assist device explantation. At follow-up (median 24.9 months [interquartile range, 16.4-43.1 months]), patients were in New York Heart Association class 1 (61.9%), 2 (28.6%), and 3 (9.5%).

CONCLUSIONS

Our 4-year experience with a standardized protocol for left ventricular assist device explantation showed a low rate of adverse events. If all criteria are met, explantation can be performed safely and with an excellent survival and functional class.

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.

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.

Machine learning for real-time prediction of complications in critical care: a retrospective study

BACKGROUND

The large amount of clinical signals in intensive care units can easily overwhelm health-care personnel and can lead to treatment delays, suboptimal care, or clinical errors. The aim of this study was to apply deep machine learning methods to predict severe complications during critical care in real time after cardiothoracic surgery.

METHODS

We used deep learning methods (recurrent neural networks) to predict several severe complications (mortality, renal failure with a need for renal replacement therapy, and postoperative bleeding leading to operative revision) in post cardiosurgical care in real time. Adult patients who underwent major open heart surgery from Jan 1, 2000, to Dec 31, 2016, in a German tertiary care centre for cardiovascular diseases formed the main derivation dataset. We measured the accuracy and timeliness of the deep learning model's forecasts and compared predictive quality to that of established standard-of-care clinical reference tools (clinical rule for postoperative bleeding, Simplified Acute Physiology Score II for mortality, and the Kidney Disease: Improving Global Outcomes staging criteria for acute renal failure) using positive predictive value (PPV), negative predictive value, sensitivity, specificity, area under the curve (AUC), and the F₁ measure (which computes a harmonic mean of sensitivity and PPV). Results were externally retrospectively validated with 5898 cases from the published MIMIC-III dataset.

FINDINGS

Of 47 559 intensive care admissions (corresponding to 42 007 patients), we included 11 492 (corresponding to 9269 patients). The deep learning models yielded accurate predictions with the following PPV and sensitivity scores: PPV 0·90 and sensitivity 0·85 for mortality, 0·87 and 0·94 for renal failure, and 0·84 and 0·74 for bleeding. The predictions significantly outperformed the standard clinical reference tools, improving the absolute complication prediction AUC by 0·29 (95% CI 0·23-0·35) for bleeding, by 0·24 (0·19-0·29) for mortality, and by 0·24 (0·13-0·35) for renal failure (p<0·0001 for all three analyses). The deep learning methods showed accurate predictions immediately after patient admission to the intensive care unit. We also observed an increase in performance in our validation cohort when the machine learning approach was tested against clinical reference tools, with absolute improvements in AUC of 0·09 (95% CI 0·03-0·15; p=0·0026) for bleeding, of 0·18 (0·07-0·29; p=0·0013) for mortality, and of 0·25 (0·18-0·32; p<0·0001) for renal failure.

INTERPRETATION

The observed improvements in prediction for all three investigated clinical outcomes have the potential to improve critical care. These findings are noteworthy in that they use routinely collected clinical data exclusively, without the need for any manual processing. The deep machine learning method showed AUC scores that significantly surpass those of clinical reference tools, especially soon after admission. Taken together, these properties are encouraging for prospective deployment in critical care settings to direct the staff's attention towards patients who are most at risk.

FUNDING

No specific funding.

Erratum to: Minimally Invasive Surgical Mitral Valve Repair: State of the Art Review

[This corrects the article on p. 14 in vol. 13, PMID: 29593831.].

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.

Finite Element Stent Modeling for the Postoperative Analysis of Transcatheter Aortic Valve Implantation

In order to evaluate the performance of stents used in transcatheter aortic valve implantation (TAVI), finite element simulations are setup to reconstruct patient-specific contact forces between implant and its surrounding tissue. Previous work used structural beam elements to setup a numerical model of the CoreValve stent used in TAVI and developed a procedure for implementing kinematic boundary conditions from noisy computer tomography (CT) scanning data. This study evaluates element size selection and quantitatively investigates the choice of a linear elastic constitutive model for the Nitinol stent under physiological loading conditions. It is shown that this simplification leads to reliable results and enables a huge reduction in computation time. Further, the procedure used to compensate for noisy postoperative CT data is tested by adding artificial noise. It is concluded that for physiologically relevant loading ranges, the procedure yields convergent results and successfully eliminates the influence of the noise.

Minimally Invasive Surgical Mitral Valve Repair: State of the Art Review

Minimally invasive surgical mitral valve repair (MVRepair) has become routine for the treatment of mitral valve regurgitation, and indications have been expanded to include reoperations. Current European Society of Cardiology/European Association for Cardio-Thoracic Surgery guidelines for the management of valvular heart disease recommended standards in terms of mitral valve disease differentiation, timing of intervention and surgical techniques to improve patient care. Numerous minimally invasive techniques to lessen the invasiveness have been described, such as the minimal-access J-sternotomy (ministernotomy), the parasternal incision, the port-access technique and the right minithoracotomy. Despite the development of catheter-based techniques, surgical repair remains the gold standard today for nearly all patients with degenerative valvular diseases and the majority of patients with other types of valvular diseases. Techniques include resection of the prolapsed segment, neo-chordae implantation and ring annuloplasty. In this review, the current indications for mitral valve surgery are summarised and state-of-the-art MVRepair techniques are highlighted.

Second-generation transapical valves: the Medtronic Engager system

The Medtronic Engager aortic valve system is a second-generation transcatheter aortic valve implantation bioprosthesis combined with a delivery system designed for over-the-wire transapical implantation of the valve. The self-expandable stent has control arms to be placed into the native aortic sinuses to achieve correct positioning of the bioprosthesis in a predefined height. The purpose of the lower skirt is to reduce paravalvular leakage. A three-leaflet, bovine pericardium valve is mounted on the stent. The implantation is facilitated by the control arms and rotational positioning of the commissural posts. A multicentre feasibility study showed promising results. The results from the following European pivotal trial led to CE mark approval in 2013. Here, we describe technical details of the device and its implantation technique and highlight special steps of the procedure.

Two- and three-dimensional transoesophageal echocardiography in large swine used as model for transcatheter heart valve therapies: standard planes and values

OBJECTIVES

Swine models are widely used to develop new techniques and materials for the treatment of heart valve disease like aortic valve and mitral valve transcatheter interventions and to train physicians in these techniques. Transoesophageal echocardiography (TOE) is crucial in these models. We defined standard planes of 2D and 3D TOE in healthy pigs undergoing transcatheter heart valve interventions.

METHODS

Twenty healthy pigs (weight 56-106 kg) underwent different mitral and aortic valve interventions (transcatheter aortic valve implantations, implantations of a mitral band, bicuspidization of the aortic valve, trans-septal punctures). For image guidance of the procedures, an adult TOE probe was introduced under direct vision in the oesophagus. Before the procedure itself was performed, a standardized protocol was used to determine normal values for anatomical and functional echocardiographic parameters.

RESULTS

Positioning of the probe was possible in all animals and ideal when achieving a distance from the front teeth (incisors) of 40-60 cm. Anteflexion and lateroflexion of the probe was necessary to achieve optimal imaging quality. 2D visualization of all relevant cardiac structures was possible. The aortic annulus diameter was 24.1 ± 2.5 mm, the sinus of valsalva diameter was 30.6 ± 4 mm and the sinotubular junction diameter was 25.2 ± 4 mm. The ascending aorta had a diameter of 24 ± 4 mm and the descending aorta a diameter of 16 ± 5 mm. The mitral valve anterior-posterior diameter was 31.8 ± 4 mm and the commissure to commissure diameter was 40.5 ± 5 mm resulting in a mitral valve area of 10.7 ± 1.5 cm(2). 3D visualization was possible for the aortic and the mitral valve. None of the animals showed any pathology except one that had a dilated left ventricle and moderate mitral valve insufficiency. Left and right ventricular dimensions and the anatomy of the aortic-, mitral-, tricuspid and pulmonary valve as well as of the aorta were comparable with those of the human anatomy.

CONCLUSIONS

2D and 3D TOE can be routinely applied as image guidance in pigs used as a model for the development and training of new techniques to treat heart valve disease.

Open vs. Minimally Invasive Mitral Valve Surgery: Surgical Technique, Indications and Results

Minimally invasive procedures are the standard approach in many centres but are still under debate in regards of inferiority compared to conventional mitral valve surgery through a median sternotomy. The aim of this review was to summarize the current literature comparing minimally invasive mitral valve surgery (MIVS) and conventional mitral valve surgery. In this review of the current literature, we summarize our findings from a recent meta-analysis and add information from papers that were published afterwards. There were no differences between patients treated minimally invasive or through a conventional sternotomy approach in regards of perioperative stroke rate and mortality. Procedural time, cardio-pulmonary-bypass time and cross-clamp time were longer in the MIVS group. In contrast, length of intensive care unit (ICU) stay and length of in hospital stay were significantly reduced in this group. Need for blood transfusion was lower in the MIVS group. Other outcomes like i.e., the rate of rethoracotomies or renal failure didn't differ between the groups. Repair rates and long-term freedom from recurrence of mitral regurgitation and reoperation are similar. Newer publications underline these findings. The current literature shows that MIVS and conventional mitral valve surgery show a similar perioperative outcome. Minimally invasive mitral valve surgery is favourable with regards to ICU stay, in hospital stay as well as need for blood transfusion.

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.

Stent Maps--Comparative Visualization for the Prediction of Adverse Events of Transcatheter Aortic Valve Implantations

Transcatheter aortic valve implantation (TAVI) is a minimally-invasive method for the treatment of aortic valve stenosis in patients with high surgical risk. Despite the success of TAVI, side effects such as paravalvular leakages can occur postoperatively. The goal of this project is to quantitatively analyze the co-occurrence of this complication and several potential risk factors such as stent shape after implantation, implantation height, amount and distribution of calcifications, and contact forces between stent and surrounding structure. In this paper, we present a two-dimensional visualization (stent maps), which allows (1) to comprehensively display all these aspects from CT data and mechanical simulation results and (2) to compare different datasets to identify patterns that are typical for adverse effects. The area of a stent map represents the surface area of the implanted stent - virtually straightened and uncoiled. Several properties of interest, like radial forces or stent compression, are displayed in this stent map in a heatmap-like fashion. Important anatomical landmarks and calcifications are plotted to show their spatial relation to the stent and possible correlations with the color-coded parameters. To provide comparability, the maps of different patient datasets are spatially adjusted according to a corresponding anatomical landmark. Also, stent maps summarizing the characteristics of different populations (e.g. with or without side effects) can be generated. Up to this point several interesting patterns have been observed with our technique, which remained hidden when examining the raw CT data or 3D visualizations of the same data. One example are obvious radial force maxima between the right and non-coronary valve leaflet occurring mainly in cases without leakages. These observations confirm the usefulness of our approach and give starting points for new hypotheses and further analyses. Because of its reduced dimensionality, the stent map data is an appropriate input for statistical group evaluation and machine learning methods.

Safety and feasibility of novel technology fusing echocardiography and fluoroscopy images during MitraClip interventions

AIMS

The EchoNavigator (EN) software (Philips Healthcare, Best, The Netherlands) enables real-time fusion of echocardiography and fluoroscopy by co-registration of the echocardiography probe on the x-ray image. We aimed to evaluate the feasibility and safety of this novel software during MitraClip procedures.

METHODS AND RESULTS

Twenty-one patients were treated with the support of EchoNavigator software (EN+ patients). The primary (safety) endpoint was the total radiation dose. Secondary endpoints were fluoroscopy and total procedure time. The measurements were compared to those of 21 patients treated immediately before the installation of EchoNavigator (EN- patients). More MitraClips (45 vs. 36) were implanted in the EN+ group, mirroring more complex interventions in this group. In EN+ patients, radiation dose (Gy/cm2) was similar compared to EN- patients (146.5±123.6 vs.146.8±134.1, p=0.9). Total procedure time (minutes) was similar in the EN+ group compared to EN- patients (136.2±50.2 vs. 125.7±51.2, p=0.5). The main benefit of the EchoNavigator is the automated real-time fusion of echocardiography and fluoroscopy, leading to easier catheter manipulation.

CONCLUSIONS

The use of EchoNavigator software was feasible and safe in all study patients. Further studies are necessary to confirm the benefits of using this software.