Prognostic value of SARS-CoV-2 on patients undergoing cardiac surgery.

OBJECTIVE: To analyze Italian Cardiac Surgery experience during the pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) identifying risk factors for overall mortality according to coronavirus disease 2019 (COVID-19) status. METHODS: From February 20 to May 31, 2020, 1354 consecutive adult patients underwent cardiac surgery at 22 Italian Centers; 589 (43.5%), patients came from the red zone. Based on COVID-19 status, 1306 (96.5%) were negative to SARS-CoV-2 (COVID-N), and 48 (3.5%) were positive to SARS-CoV-2 (COVID-P); among the COVID-P 11 (22.9%) and 37 (77.1%) become positive, before and after surgery, respectively. Surgical procedures were as follows: 396 (29.2%) isolated coronary artery bypass grafting (CABG), 714 (52.7%) isolated non-CABG procedures, 207 (15.3%) two associate procedures, and three or more procedures in 37 (2.7%). Heart failure was significantly predominant in group COVID-N (10.4% vs. 2.5%, p = .01). RESULTS: Overall in-hospital mortality was 1.6% (22 cases), being significantly higher in COVID-P group (10 cases, 20.8% vs. 12, 0.9%, p < .001). Multivariable analysis identified COVID-P condition as a predictor of in-hospital mortality together with emergency status. In the COVID-P subgroup, the multivariable analysis identified increasing age and low oxygen saturation at admission as risk factors for in-hospital mortality. CONCLUSION: As expected, SARS-CoV-2 infection, either before or soon after cardiac surgery significantly increases in-hospital mortality. Moreover, among COVID-19-positive patients, older age and poor oxygenation upon admission seem to be associated with worse outcomes.

Right ventricular assessment can improve prognostic value of Euroscore II.

BACKGROUND: The aim of this multicenter prospective study was to evaluate the prognostic weight of preoperative right ventricular assessment on early mortality in cardiac surgery. METHODS: This is a multicenter prospective observational study performed by the Italian Group of Research for Outcome in Cardiac Surgery (GIROC) including 11 centers. From October 2017 to March 2019, out of 923 patients undergoing cardiac surgery, 28 patients with some missing data were excluded and 895 patients were enrolled in the study right ventricular dilatation was defined as a basal end-diastolic diameter >42 mm. The right ventricle (RV) function was assessed using the combination of three parameters: fractional area changing (FAC), tricuspid annular plane systolic excursion (TAPSE), and S'-wave using tissue Doppler imaging (TDI-S'); RV dysfunction was defined as the presence of at least two of the following cutoffs: FAC <35%, TAPSE <17 mm, and TDI S' <9.5 mm RESULTS: Among the entire cohort, 624 (70%) showed normal RV, 92 (10%) isolated RV dilatation, 154 (17%) isolated RV dysfunction, and 25 (3%) both RV dilatation and dysfunction. Non-surviving patients showed a significantly higher rate of RV alteration at multivariable analysis, RV status was found to be an independent predictor for higher in-hospital mortality beside Euroscore II. CONCLUSIONS: This prospective multicenter observation study shows the importance to assess RV preoperatively and to include both RV function and dimension in a risk score model such as Euroscore II to implement its predictivity, since PH cannot always mirror the status of the right ventricle.

Spontaneous Coronary Artery Dissection after Minimally Invasive Mitral Valve Repair.

Spontaneous coronary artery dissection is a rare condition usually encountered in young women without risk factors for atherosclerotic disease but with tortuous coronary artery or contemporary presence of fibromuscular dysplasia. Sometimes spontaneous coronary dissection occurs in patients with atherosclerotic disease, although without significant epicardial coronary artery stenosis. We report a case of a patient who underwent minimally invasive mitral valve repair, whose initially uneventful postoperative course was complicated by spontaneous coronary artery dissection of the left main causing a life threatening condition. A subsequent emergency sternotomy was required to perform a coronary artery bypass.

Aortic valve replacement in familial hypercholesterolemia: not an ordinary procedure.

Familial hypercholesterolemia is an inherited disorder with incidences of approximately 1:500 and 1:1,000,000 in heterozygous and homozygous form respectively. Affected patients usually show early coronary artery disease and severe aortic root calcification, despite optimization of therapy. We report a case of a 64-year-old woman affected by heterozygous familial hypercholesterolemia which presented dyspnea and anginal symptoms due to a severely calcified aortic root causing valve stenosis and narrowed sinotubular junction. Aortic valve replacement and aortic root enlargement were performed using the Manougian procedure. Even for experiences surgeons, this surgery could prove challenging for this group of patients due to aggressive degenerative tissue calcification of the aortic root, which often presents an extremely calcified aortic valve with a small annulus associated to a narrowed sinotubular junction.

Cortical facilitation of tactile afferents during the preparation of a body weight transfer when standing on a biomimetic surface.

Self-generated movement shapes tactile perception, but few studies have investigated the brain mechanisms involved in the processing of the mechanical signals related to the static and transient skin deformations generated by forces and pressures exerted between the foot skin and the standing surface. We recently found that standing on a biomimetic surface (i.e., inspired by the characteristics of mechanoreceptors and skin dermatoglyphics), that magnified skin-surface interaction, increased the sensory flow to the somatosensory cortex and improved balance control compared to standing on control (e.g., smooth) surfaces. In this study, we tested whether the well-known sensory suppression that occurs during movements is alleviated when the tactile afferent signal becomes relevant with the use of a biomimetic surface. Eyes-closed participants (n = 25) self-stimulated their foot cutaneous receptors by shifting their body weight toward one of their legs while standing on either a biomimetic or a control (smooth) surface. In a control task, similar forces were exerted on the surfaces (i.e., similar skin-surface interaction) by passive translations of the surfaces. Sensory gating was assessed by measuring the amplitude of the somatosensory-evoked potential over the vertex (SEP, recorded by EEG). Significantly larger and shorter SEPs were found when participants stood on the biomimetic surface. This was observed whether the forces exerted on the surface were self-generated or passively generated. Contrary to our prediction, we found that the sensory attenuation related to the self-generated movement did not significantly differ between the biomimetic and control surfaces. However, we observed an increase in gamma activity (30-50 Hz) over centroparietal regions during the preparation phase of the weight shift only when participants stood on the biomimetic surface. This result might suggest that gamma-band oscillations play an important functional role in processing behaviorally relevant stimuli during the early stages of body weight transfer.

When mechanical engineering inspired from physiology improves postural-related somatosensory processes.

Despite numerous studies uncovering the neural signature of tactile processing, tactile afferent inputs relating to the contact surface has not been studied so far. Foot tactile receptors being the first stimulated by the relative movement of the foot skin and the underneath moving support play an important role in the sensorimotor transformation giving rise to a postural reaction. A biomimetic surface, i.e., complying with the skin dermatoglyphs and tactile receptors characteristics should facilitate the cortical processes. Participants (n = 15) stood either on a biomimetic surface or on two control surfaces, when a sudden acceleration of the supporting surface was triggered (experiment 1). A larger intensity and shorter somatosensory response (i.e., SEP) was evoked by the biomimetic surface motion. This result and the associated decrease of theta activity (5-7 Hz) over the posterior parietal cortex suggest that increasing the amount of sensory input processing could make the balance task less challenging when standing on a biomimetic surface. This key point was confirmed by a second experiment (n = 21) where a cognitive task was added, hence decreasing the attentional resources devoted to the balance motor task. Greater efficiency of the postural reaction was observed while standing on the biomimetic than on the control surfaces.

Impact of Mitral Regurgitation Etiology on Mitral Surgery After Transcatheter Edge-to-Edge Repair: From the CUTTING-EDGE Registry.

BACKGROUND: Although >150,000 mitral TEER procedures have been performed worldwide, the impact of MR etiology on MV surgery after TEER remains unknown. OBJECTIVES: The authors sought to compare outcomes of mitral valve (MV) surgery after failed transcatheter edge-to-edge repair (TEER) stratified by mitral regurgitation (MR) etiology. METHODS: Data from the CUTTING-EDGE registry were retrospectively analyzed. Surgeries were stratified by MR etiology: primary (PMR) and secondary (SMR). MVARC (Mitral Valve Academic Research Consortium) outcomes at 30 days and 1 year were evaluated. Median follow-up was 9.1 months (IQR: 1.1-25.8 months) after surgery. RESULTS: From July 2009 to July 2020, 330 patients underwent MV surgery after TEER, of which 47% had PMR and 53.0% had SMR. Mean age was 73.8 ± 10.1 years, median STS risk at initial TEER was 4.0% (IQR: 2.2%-7.3%). Compared with PMR, SMR had a higher EuroSCORE, more comorbidities, lower LVEF pre-TEER and presurgery (all P < 0.05). SMR patients had more aborted TEER (25.7% vs 16.3%; P = 0.043), more surgery for mitral stenosis after TEER (19.4% vs 9.0%; P = 0.008), and fewer MV repairs (4.0% vs 11.0%; P = 0.019). Thirty-day mortality was numerically higher in SMR (20.4% vs 12.7%; P = 0.072), with an observed-to-expected ratio of 3.6 (95% CI: 1.9-5.3) overall, 2.6 (95% CI: 1.2-4.0) in PMR, and 4.6 (95% CI: 2.6-6.6) in SMR. SMR had significantly higher 1-year mortality (38.3% vs 23.2%; P = 0.019). On Kaplan-Meier analysis, the actuarial estimates of cumulative survival were significantly lower in SMR at 1 and 3 years. CONCLUSIONS: The risk of MV surgery after TEER is nontrivial, with higher mortality after surgery, especially in SMR patients. These findings provide valuable data for further research to improve these outcomes.

Uncertainty model for contact instability prediction.

Contact between sliding bodies can cause vibrations leading to instability. The problem of squeal due to high frequency noise from brake systems is due to unstable vibrations generated at the contact interface between the pad and disk. Squeal noise is characterized by extreme unpredictability due to large uncertainties on the values of parameters of the system. Parametrical complex eigenvalue analysis is a common tool used to predict squeal instability. In this paper a substructured linear finite element model of a simplified brake system is studied. A parametrical analysis is focused on a test case and compared to experimental results. The analysis is developed as a function of the parameters assumed to be the most influential but also the most uncertain: friction coefficient and the parameters driving the dynamics of the system. The uncertainties are accounted for by considering parameters such as random variables. A Monte Carlo simulation and a probabilistic technique are performed simultaneously to study the probability of squeal occurrence. Finally, a reduced model based on the transfer function calculated at the contact is developed to perform the analysis with reduced computational effort.

Does preoperative degree of aortic insufficiency influence early and midterm results of sparing surgery?

OBJECTIVE: Aortic valve-sparing operations have shown excellent results in patients with aortic root and or ascending aorta aneurysm. Aortic valve regurgitation is frequently detected in these patients as a result of significant dilation of the aortic root.The aim of this study was to assess the impact of preoperative aortic incompetence degree on the early and midterm outcomes of sparing surgery. METHODS: From September 2001 to July 2006, 84 patients with aortic root aneurysm underwent aortic valve-sparing surgery according to the reimplantation technique. Depending on preoperative grade of aortic insufficiency (AI), two groups were identified: 31 patients (study group, SG) with AI grade III-IV and 53 (control group, CG) with AI grade II or less. The Gelweave Valsalva prosthesis was used in 76 patients (90.5%). Intraoperative, perioperative variables and outcomes at follow-up were retrospectively compared between the groups. RESULTS: Patient demographics and types of operations were comparable between groups. Early mortality rates were almost identical in both groups (3.2% SG vs. 5.7% CG; P = 0.961); at follow-up (FU), no patient died in both groups. Grade III-IV AI was similar in both groups early postoperatively (6.4% SG vs. 3.8% CG; P = 0.981) and during follow-up (13.3% vs. 8%; P = 0.755). Reoperaton rate for AI was 3.3% in SG vs. 6% in CG (P = 0.980). CONCLUSIONS: Preoperative degree of aortic regurgitation does not impair the outcomes of the valve-sparing operation which seem to depend on more factors. Early results were affected by the learning curve but midterm outcomes showed a progressive improvement. Patients with satisfactory reconstruction show stable results over time.

Numerical modeling of bone as a multiscale poroelastic material by the homogenization technique.

Bone is a complex material showing a hierarchical and porous structure but also a natural ability to remodel thanks to cells sensitive to fluid flows. Based on these characteristics, a multiscale numerical model has been developed in order to represent the bone response under mechanical solicitation. It relies on the homogenization technique, simulating bone as a homogeneous structure having a porous microstructure saturated with bone fluid. The numerical modeling of the loading of a finite volume of bone enables the determination of an equivalent poroelastic stiffness. Focusing on two extreme fluid boundary conditions, the study of the corresponding structural response provides an overview of the fluid contribution to the poroelastic behavior, impacting the stiffness of the considered material. This parameter is either reduced (when the fluid can flow out of the structure) or increased (when the fluid is kept inside the structure) and quantified through this model. The presented poroelastic numerical model is here developed in the perspective of providing a bio-reliable model of bones, to determine the critical parameters that might impact bone remodeling.

Effect of damping on the propensity of squeal instability: an experimental investigation.

Friction induced vibrations in automotive brakes is recognized as a major problem in industry. Squeal is a difficult subject because of its unpredictability caused by a not completely understood sensitivity to variation of the system parameters. In the literature several analytical and numerical studies deal with the relationship between damping and system propensity to have instability. These studies highlight the existence of a nonintuitive effect of damping distribution on modal coupling that gives rise to the unstable vibrations. The complexity of commercial brakes and the difficulties to identify the values of modal damping in brake assemblies lead to the necessity to rely on experimental analysis using simplified test rigs. This paper presents an experimental investigation of the relationship between the distribution of modal damping and the propensity to develop squeal in a beam-on-disk setup, which reliably reproduces squeal events with easy control and measurement of the damping of the disk and the beam, respectively. The experiments highlight the key role played by the modal damping distribution on squeal: A nonuniform repartition of the modal damping causes an increase of the squeal propensity.

Pseudoaneurysm fistulized into pulmonary artery 13 years after aortic surgery.

Pseudoaneurysm formation some years after aortic root or ascending aorta surgery, complicated by fistula formation through a branch of the pulmonary artery, is a rare condition described only in case reports. We describe a case of this rare complication in a 58-year-old man, which occurred 13 years after aortic surgery and was characterized by a huge pseudoaneurysm of 70 mm that fistulized into the right pulmonary artery, causing a life-threatening situation.

Tactile Perception and Friction-Induced Vibrations: Discrimination of Similarly Patterned Wood-Like Surfaces.

The tactile perception of a surface texture is mediated by factors such as material, topography, and vibrations induced by the sliding contact. In this paper, sensory characterizations are developed together with topographical and tribo-tactile characterizations to relate perceived features with objective measurements of tribological and dynamic signals. Two sets of surface samples are used in this study: the first set is made of a commercial floor covering tiles that aim at counter-typing natural wood flooring, with both a visual and a tactile texture mimicking wood. A second set is custom-made by replicating the first set using a plain purple polyurethane resin. The comparison between tribo-tactile signals and sensory analysis allowed the identification of objective indices for textures with slight topographical differences. Even though the topography of the replicated samples is the same as their corresponding commercial products, the fact that the material is different, induces differences in the contact and vibrational parameters. This in turn modifies the discrimination performances during the sensory experiment. Tactile characteristics collected during sensory procedures are found to be in agreement with objective indices such as friction coefficients and induced vibrations.

Off-pump minimally invasive direct coronary artery bypass in patients with cosmetic prosthesis for pectus excavatum.

Pectus excavatum can be associated with coronary artery diseases that can become difficult to manage in urgent situations. We describe the use of an off-pump minimally invasive direct coronary artery bypass (MIDCAB) through the fourth intercostal space incision in a patient with pectus excavatum and acute coronary syndrome who previously underwent a cosmetic prosthesis implantation. The patient refused any surgical procedure that could compromise the integrity of his cosmetic prosthesis and a left mini-thoracotomy was a good option to avoid the removal of the prosthesis. The preservation of the integrity of the thoracic cage enhanced chest wall stability and pulmonary function and permitted avoidance of inadvertent cardiac structure iatrogenic injuries. MIDCAB was optimal for the exposure of the left internal thoracic artery and the left anterior descending artery. The deformity of the chest should not be considered as an absolute contraindication to off-pump MIDCAB when other surgical options are not viable, even in emergency situations.

Myocardial infarction and rupture after bronchial artery embolization.

Bronchial artery embolization is a well-known treatment for hemoptysis. Adverse events of this procedure include multiple systemic embolism and infarction. Myocardial infarction has been recently reported during bronchial artery embolization, owing to the presence of a coronary-to-bronchial artery fistula. We report the management of an ischemic left ventricular free wall rupture caused by bronchial artery embolization in a patient with massive hemoptysis, bronchiectasis, and undetected coronary-to-bronchial artery anomalous connection.

Sternal wrapping: developments and results.

BACKGROUND: Postoperative sternal wound complications are infrequent events that negatively affect recovery and may have serious consequences. Sternal wrapping, a technique of sternal care, has hemostatic properties without bone wax, and offers mechanical and microbiologic protection. METHODS: From February 1998 to December 2011, 258 patients in 2 Italian institutions underwent various cardiac surgery procedures with sternal wrapping in place, and were followed up for no less then 6 months. RESULTS: Two (0.8%) extremely compromised patients with ischemic sternal osteonecrosis and deep sternal wound infection required a sternal stabilizing procedure. Four (2%) other patients developed sternal wound complications that were treated entirely medically; 3 of them were very trivial, and 1 was an atypical mediastinitis without sternal involvement. Overall, 46.1% of patients (45.3% of isolated coronary artery bypass, 49.3% of isolated on-pump coronary artery bypass, and 18.2% of off-pump coronary artery bypass patients) were transfused. None of the complications was related to sternal wrapping, bleeding from the sternal edge, or sternal wound problems. CONCLUSIONS: Sternal wrapping showed a very low incidence and severity of sternal wound complications, with good prevention of sternal osteomyelitis. Hemostatic properties were satisfactory, with transfusion rates within an acceptable range.

Pulmonary pseudoaneurysm: uncommon complication after total aortic arch operation.

Pulmonary pseudoaneurysms are an uncommon but life-threatening condition of congenital or acquired cause, most commonly involving the branch pulmonary arteries and generally requiring emergent intervention. We describe a case of postoperative main pulmonary artery pseudoaneurysm after a complex aortic arch procedure, in which thoracic computed tomography provided full information for its definition before surgical correction.