Hyperglycemia-simulating environment attenuated experimentally induced calcification in cultured human aortic valve interstitial cells.

Objectives: The role of diabetes mellitus as a risk factor for the development of calcific aortic valve disease has not been fully clarified. Aortic valve interstitial cells (VICs) have been suggested to be crucial for calcification of the valve. Induced calcification in cultured VICs is a good in vitro model for aortic valve calcification. The purpose of this study was to investigate whether increased glucose levels increase experimentally induced calcification in cultured human VICs. Design: VICs were isolated from explanted calcified aortic valves after valve replacement. Osteogenic medium induced calcification of cultured VICs at different glucose levels (5, 15, and 25 mM). Calcium deposits were visualized using Alizarin Red staining and measured spectrophotometrically. Results: The higher the glucose concentration, the lower the level of calcification. High glucose (25 mM) reduced calcification by 52% compared with calcification at a physiological (5 mM) glucose concentration (correlation and regression analysis: r = -0.55, p = .025 with increased concentration of glucose). Conclusions: In vitro hyperglycemia-like conditions attenuated calcification in VICs. High glucose levels may trigger a series of events that secondarily stimulate calcification of VICs in vivo.

Non-invasive myocardial work in aortic stenosis: validation and improvement in left ventricular pressure estimation.

AIMS: The non-invasive myocardial work index (MWI) has been validated in patients without aortic stenosis (AS). A thorough assessment of methodological limitations is warranted before this index can be applied to patients with AS. METHODS AND RESULTS: We simultaneously measured left ventricular pressure (LVP) by using a micromanometer-tipped catheter and obtained echocardiograms in 20 patients with severe AS. We estimated LVP curves and calculated pressure-strain loops using three different models: (i) the model validated in patients without AS; (ii) the same model, but with pressure at the aortic valve opening (AVO) adjusted to diastolic cuff pressure; and (iii) a new model based on the invasive measurements from patients with AS. Valvular events were determined by echocardiography. Peak LVP was estimated as the sum of the mean aortic transvalvular gradient and systolic cuff pressure. In same-beat comparisons between invasive and estimated LVP curves, Model 1 significantly overestimated early systolic pressure by 61 ± 5 mmHg at AVO compared with Models 2 and 3. However, the average correlation coefficients between estimated and invasive LVP traces were excellent for all models, and the overestimation had limited influence on MWI, with excellent correlation (r = 0.98, P < 0.001) and good agreement between the MWI calculated with estimated (all models) and invasive LVP. CONCLUSION: This study confirms the validity of the non-invasive MWI in patients with AS. The accuracy of estimated LVP curves improved when matching AVO to the diastolic pressure in the original model, mirroring that of the AS-specific model. This may sequentially enhance the accuracy of regional MWI assessment.

Platelet Function is Preserved After Moderate Cardiopulmonary Bypass Times But Transiently Impaired After Protamine.

OBJECTIVES: Previous studies have described impaired platelet function after cardiopulmonary bypass (CPB). Whether this is still valid in contemporary cardiac surgery is unclear. This study aimed to quantify changes in function and number of platelets during CPB in a present-day cardiac surgery cohort. DESIGN: Prospective, controlled clinical study. SETTING: A single-center university hospital. PARTICIPANTS: Thirty-nine patients scheduled for coronary artery bypass graft surgery with CPB. INTERVENTIONS: Platelet function and numbers were measured at 6 timepoints in 39 patients during and after coronary artery bypass graft surgery; at baseline before anesthesia, at the end of CPB, after protamine administration, at intensive care unit (ICU) arrival, 3 hours after ICU arrival, and on the morning after surgery. MEASUREMENTS AND MAIN RESULTS: Platelet function was assessed with impedance aggregometry and flow cytometry. Platelet numbers are expressed as actual concentration and as numbers corrected for dilution using hemoglobin as a reference marker. There was no consistent impairment of platelet function during CPB with either impedance aggregometry or flow cytometry. After protamine administration, a decrease in platelet function was seen with impedance aggregometry and for some markers of activation with flow cytometry. Platelet function was restored 3 hours after arrival in the ICU. During CPB (85.0 ± 21 min), the number of circulating platelets corrected for dilution increased from 1.73 ± 0.42 × 109/g to 1.91 ± 0.51 × 109/g (p < 0.001). CONCLUSIONS: During cardiac surgery with moderate CPB times, platelet function was not impaired, and no consumption of circulating platelets could be detected. Administration of protamine transiently affected platelet function.

Black swans and fat tails. / Sorte svaner og fete haler.

Economists use the terms black swans and fat-tailed distributions to describe rare, but high-impact events in areas ranging from the financial markets to climate change. We would do well to take such phenomena into account ­ including in medicine.

Multi-omics of in vitro aortic valve calcification.

Heart valve calcification is an active cellular and molecular process that partly remains unknown. Osteogenic differentiation of valve interstitial cells (VIC) is a central mechanism in calcific aortic valve disease (CAVD). Studying mechanisms in CAVD progression is clearly needed. In this study, we compared molecular mechanisms of osteogenic differentiation of human VIC isolated from healthy donors or patients with CAVD by RNA-seq transcriptomics in early timepoint (48 h) and by shotgun proteomics at later timepoint (10th day). Bioinformatic analysis revealed genes and pathways involved in the regulation of VIC osteogenic differentiation. We found a high amount of stage-specific differentially expressed genes and good accordance between transcriptomic and proteomic data. Functional annotation of differentially expressed proteins revealed that osteogenic differentiation of VIC involved many signaling cascades such as: PI3K-Akt, MAPK, Ras, TNF signaling pathways. Wnt, FoxO, and HIF-1 signaling pathways were modulated only at the early timepoint and thus probably involved in the commitment of VIC to osteogenic differentiation. We also observed a significant shift of some metabolic pathways in the early stage of VIC osteogenic differentiation. Lentiviral overexpression of one of the most upregulated genes (ZBTB16, PLZF) increased calcification of VIC after osteogenic stimulation. Analysis with qPCR and shotgun proteomics suggested a proosteogenic role of ZBTB16 in the early stages of osteogenic differentiation.

Models and Techniques to Study Aortic Valve Calcification in Vitro, ex Vivo and in Vivo. An Overview.

Aortic valve stenosis secondary to aortic valve calcification is the most common valve disease in the Western world. Calcification is a result of pathological proliferation and osteogenic differentiation of resident valve interstitial cells. To develop non-surgical treatments, the molecular and cellular mechanisms of pathological calcification must be revealed. In the current overview, we present methods for evaluation of calcification in different ex vivo, in vitro and in vivo situations including imaging in patients. The latter include echocardiography, scanning with computed tomography and magnetic resonance imaging. Particular emphasis is on translational studies of calcific aortic valve stenosis with a special focus on cell culture using human primary cell cultures. Such models are widely used and suitable for screening of drugs against calcification. Animal models are presented, but there is no animal model that faithfully mimics human calcific aortic valve disease. A model of experimentally induced calcification in whole porcine aortic valve leaflets ex vivo is also included. Finally, miscellaneous methods and aspects of aortic valve calcification, such as, for instance, biomarkers are presented.

Thrombus formation in the noncoronary sinus of Valsalva following primary graft dysfunction.

We hereby present a case of thrombus formation in the noncoronary sinus of Valsalva following primary graft dysfunction. The case highlights that stagnant and nonpulsatile flow can form thrombi in the noncoronary sinus since this sinus does not have a natural distal runoff.

Quantification of platelet function - a comparative study of venous and arterial blood using a novel flow cytometry protocol.

Studies of platelet function in surgical patients often involve both arterial and venous sampling. Possible effects of different sampling sites could be important, but have not been thoroughly investigated. We aimed to compare platelet function in arterial and venous blood samples using a novel flow cytometry protocol and impedance aggregometry. Arterial and venous blood was collected before anesthesia in 10 patients undergoing cardiac surgery of which nine was treated with acetylsalicylic acid until the day before surgery. Flow cytometry included simultaneous analysis of phosphatidylserine exposure, active conformation of the fibrinogen receptor (PAC-1 binding), α-granule and lysosomal release (P-selectin and LAMP-1 exposure) and mitochondrial membrane integrity. Platelets were activated with ADP or peptides activating thrombin receptors (PAR1-AP/PAR4-AP) or collagen receptor GPVI (CRP-XL). Leukocyte-platelet conjugates and P-selectin exposure were evaluated immediately in fixated samples. For impedance aggregometry (Multiplate®), ADP, arachidonic acid, collagen and PAR1-AP (TRAP) were used as activators. Using impedance aggregometry and in 27 out of 37 parameters studied with flow cytometry there was no significant difference between venous and arterial blood sampling. Arterial blood showed more PAC-1 positive platelets when activated with PAR1-AP or PAR4-AP and venous blood showed more monocyte-platelet and neutrophil-platelet conjugates and higher phosphatidylserine exposure with CRP-XL alone and combined with PAR1-AP or PAR4-AP. We found no differences using impedance aggregometry. In conclusion, testing of platelet function by flow cytometry and impedance aggregometry gave comparable results for most of the studied parameters in venous and arterial samples. Flow cytometry identified differences in PAC-1 binding when activated with PAR1-AP, exposure of phosphatidyl serine and monocyte/neutrophil-platelet conjugates, which might reflect differences in blood sampling technique or in flow conditions in this patient cohort with coronary artery disease. These differences might be considered when comparing data from different sample sites, but caution should be exercised if a different protocol is used or another patient group is studied.

Markers of extracellular matrix remodeling and systemic inflammation in patients with heritable thoracic aortic diseases.

Background: In approximately 20% of patients with thoracic aortic aneurysms or dissections a heritable thoracic aortic disease (HTAD) is suspected. Several monogenic connective tissue diseases imply high risk of aortic disease, including both non-syndromic and syndromic forms. There are some studies assessing inflammation and extracellular matrix remodeling in patients with non-hereditary aortic disease, but such studies in patients with hereditary diseases are scarce. Aims: To quantify markers of extracellular matrix (ECM) and inflammation in patients with vascular connective tissue diseases versus healthy controls. Methods: Patients with Loeys-Dietz syndrome (LDS, n = 12), Marfan syndrome (MFS, n = 11), and familial thoracic aortic aneurysm 6 (FTAA6, n = 9), i.e., actin alpha 2 (ACTA2) pathogenic variants, were recruited. Exome or genome sequencing was performed for genetic diagnosis. Several markers of inflammation and ECM remodeling were measured in plasma by enzyme immunoassays. Flow cytometry of T-cell subpopulations was performed on a subgroup of patients. For comparison, blood samples were drawn from 14 healthy controls. Results: (i) All groups of HTAD patients had increased levels matrix metalloproteinase-9 (MMP-9) as compared with healthy controls, also in adjusted analyses, reflecting altered ECM remodeling. (ii) LDS patients had increased levels of pentraxin 3 (PTX3), reflecting systemic inflammation. (iii) LDS patients have increased levels of soluble CD25, a marker of T-cell activation. Conclusion: Our data suggest that upregulated MMP-9, a matrix degrading enzyme, is a common feature of several subgroups of HTAD. In addition, LDS patients have increased levels of PTX3 reflecting systemic and in particular vascular inflammation.

Early results after aortic annuloplasty with a complete external Dacron band.

OBJECTIVE: This study evaluates the early results of our initial experience with aortic annuloplasty using a complete external Dacron band in the setting of type Ic or type II aortic regurgitation (AR). METHODS: From May 2017 to August 2019, 16 patients (88% bicuspid aortic valves, no patients with connective tissue disorders) underwent aortic annuloplasty with an external complete Dacron band. Clinical and echocardiographic follow-up was 100% complete. Clinical and echocardiographic follow-up averaged 24.4 ± 9.3 and 15.1 ±  8.3 months, respectively. RESULTS: Mean cardiopulmonary and cross-clamp times were 105 ± 15 (72-127) and 86 ± 15 (51-113) min, respectively. Early and late mortality was 0%, with no incidents of endocarditis or cerebrovascular events during the follow-up. Two patients were re-operated during the follow-up, one due recurrent aortic regurgitation (12 months after the first operation) yielding a freedom from reoperation due to AR at 1 year and 3 years of 100% ± 0% and 93.3% ± 5.7%, respectively. Based on the latest echocardiogram, five patients had either none or trivial AR, six had mild AR, and three had mild-to-moderate AR. CONCLUSIONS: The early clinical and echocardiographic results after using a complete external Dacron band are promising; however, more data and longer follow-up are needed to determine its role in annular management during aortic valve repair.

Total aortic arch replacement using the thoraflex hybrid prosthesis: early- and medium-term results from a Scandinavian center.

OBJECTIVE: The purpose of this study was to assess our early experience with the Thoraflex hybrid prosthesis. Design. This was a retrospective, single-center cohort study. RESULTS: Between December 2014 and December 2019, 34 patients underwent total aortic arch replacement with the Thoraflex hybrid prosthesis. Fifteen of the patients had pre-operative chronic aortic dissection. The mean cardiopulmonary bypass time was 200 ± 35 min, aortic cross clamp time 114 ± 34 min, deep circulatory arrest time to the lower body 60 ± 22 min, and selective antegrade cerebral perfusion time 67 ± 24 min. The rate of stroke was 11.7% (4/34), paraparesis was 8.8% (3/34) and renal failure was 11.7% (4/34). No patient required permanent dialysis. Three (8.8%) patients died within the first 30 days postoperatively. All early deaths were due to stroke or spinal cord complications. During follow-up, an additional four patients died. Average follow-up was 32.4 ± 19.4 months (1102 patient-months) and was 100% complete. Survival at 12 months and 36 months was 88% ± 7.2% and 75% ± 12.7%, respectively. CONCLUSIONS: The Thoraflex hybrid prosthesis can be used in the setting of total aortic arch replacement with good early- and medium-term results. Stroke and spinal cord complications remain an important source of early mortality.

Lung autotransplantation and extra-anatomic bypass to treat an aortobronchial fistula after previous surgery for aortic coarctation.

Lung autotransplantation can be a surgical alternative to gain access to the posterior mediastinum and the thoracic portion of the descending aorta through a sternotomy. We present a case of hemoptysis and bronchial obstruction due to a presumed infected aortobronchial fistula, secondary to stent graft placement in a patient with multiple previous surgeries for aortic coarctation, treated with lung autotransplantation and an extra-anatomic bypass.

Protamine stimulates platelet aggregation in vitro with activation of the fibrinogen receptor and alpha-granule release, but impairs secondary activation via ADP and thrombin receptors.

Heparin and protamine are fundamental in the management of anticoagulation during cardiac surgery. Excess protamine has been associated with increased bleeding. Interaction between protamine and platelet function has been demonstrated but the mechanism remains unclear. We examined the effect of protamine on platelet function in vitro using impedance aggregometry, flow cytometry, and thrombin generation. Platelets were exposed to protamine at final concentrations of 0, 20, 40, and 80 µg/mL, alone or together with adenosine diphosphate (ADP) or thrombin PAR1 receptor-activating peptide (TRAP). We found that in the absence of other activators, protamine (80 µg/mL) increased the proportion of platelets with active fibrinogen receptor (binding of PAC-1) from 3.6% to 97.0% (p < .001) measured with flow cytometry. Impedance aggregometry also increased slightly after exposure to protamine alone. When activated with ADP or TRAP protamine at 80 µg/mL reduced aggregation, from 73.8 ± 29.4 U to 46.9 ± 21.1 U (p < .001) with ADP and from 126.4 ± 16.1 U to 94.9 ± 23.7 U (p < .01) with TRAP. P-selectin exposure (a marker of alpha-granule release) measured by median fluorescence intensity (MFI) increased dose dependently with protamine alone, from 0.76 ± 0.20 (0 µg/mL) to 10.2 ± 3.1 (80 µg/mL), p < .001. Protamine 80 µg/mL by itself resulted in higher MFI (10.16 ± 3.09) than activation with ADP (2.2 ± 0.7, p < .001) or TRAP (5.7 ± 2.6, p < .01) without protamine. When protamine was combined with ADP or TRAP, there was a concentration-dependent increase in the alpha-granule release. In conclusion, protamine interacts with platelets in vitro having both a direct activating effect and impairment of secondary activation of aggregation by other agonists.

Correction to: Resection of a plasma cell granuloma combining a conventional posterolateral left-sided thoracotomy with a minimally invasive valve approach.

The corresponding author name should read as "Kvitting JP" in PubMed and other indexing websites.

Interstitial cells in calcified aortic valves have reduced differentiation potential and stem cell-like properties.

Valve interstitial cells (VICs) are crucial in the development of calcific aortic valve disease. The purpose of the present investigation was to compare the phenotype, differentiation potential and stem cell-like properties of cells from calcified and healthy aortic valves. VICs were isolated from human healthy and calcified aortic valves. Calcification was induced with osteogenic medium. Unlike VICs from healthy valves, VICs from calcified valves cultured without osteogenic medium stained positively for calcium deposits with Alizarin Red confirming their calcific phenotype. Stimulation of VICs from calcified valves with osteogenic medium increased calcification (p = 0.02), but not significantly different from healthy VICs. When stimulated with myofibroblastic medium, VICs from calcified valves had lower expression of myofibroblastic markers, measured by flow cytometry and RT-qPCR, compared to healthy VICs. Contraction of collagen gel (a measure of myofibroblastic activity) was attenuated in cells from calcified valves (p = 0.04). Moreover, VICs from calcified valves, unlike cells from healthy valves had lower potential to differentiate into adipogenic pathway and lower expression of stem cell-associated markers CD106 (p = 0.04) and aldehyde dehydrogenase (p = 0.04). In conclusion, VICs from calcified aortic have reduced multipotency compared to cells from healthy valves, which should be considered when investigating possible medical treatments of aortic valve calcification.

Do annuloplasty rings designed to treat ischemic/functional mitral regurgitation alter left-ventricular dimensions in the acutely ischemic ovine heart?

OBJECTIVE: To quantify the effects of annuloplasty rings designed to treat ischemic/functional mitral regurgitation on left ventricular septal-lateral (S-L) and commissure-commissure (C-C) dimensions. METHODS: Radiopaque markers were placed as opposing pairs on the S-L and C-C aspects of the mitral annulus and the basal, equatorial, and apical level of the left ventricle (LV) in 30 sheep. Ten true-sized Carpentier-Edwards Physio (PHY), Edwards IMR ETlogix (ETL), and GeoForm (GEO; all from Edwards Lifesciences, Irvine, Calif) annuloplasty rings were inserted in a releasable fashion. After 90 seconds of left circumflex artery occlusion with the ring implanted (RING), 4-dimensional marker coordinates were obtained using biplane videofluoroscopy. After ring release, another data set was acquired after another 90 seconds of left circumflex artery occlusion (NO RING). S-L and C-C diameters were computed as the distances between the respective marker pairs at end-diastole. Percent change in diameters was calculated between RING versus NO RING as 100 × (diameter in centimeters [RING] - diameter in centimeters [NO RING])/diameter in centimeters [NO RING]). RESULTS: Compared with NO RING, all ring types (PHY, ETL, and GEO) reduced mitral annular S-L dimensions by -20.7 ± 5.6%, -26.8 ± 3.9%, and -34.5 ± 3.8%, respectively. GEO reduced the S-L dimensions of the LV at the basal level only by -2.3 ± 2.4%, whereas all other S-L dimensions of the LV remained unchanged with all 3 rings implanted. PHY, ETL, and GEO reduced mitral annular C-C dimensions by -17.5 ± 4.8%, -19.6 ± 2.5, and -8.3 ± 4.9%, respectively, but none of the rings altered the C-C dimensions of the LV. CONCLUSIONS: Despite radical reduction of mitral annular size, disease-specific ischemic/functional mitral regurgitation annuloplasty rings do not induce relevant changes of left ventricular dimensions in the acutely ischemic ovine heart.

Resection of a plasma cell granuloma combining a conventional posterolateral left-sided thoracotomy with a minimally invasive valve approach.

Plasma cell granuloma (PCG) is a rare benign tumor that is difficult to differentiate from malignancy. Depending on the location of the PCG, surgical management can be challenging. We describe a patient with a PCG involving the left lower lobe extending into the left atrium, that was resected en bloc using a conventional posterolateral thoracotomy combined with a surgical approach predominantly used for minimally invasive mitral valve surgery. This case illustrates how it is possible to utilize a technique used for cardiac surgery for tumors of pulmonary origin involving the heart.

Validation of a Holographic Display for Quantification of Mitral Annular Dynamics by Three-Dimensional Echocardiography.

BACKGROUND: Three-dimensional (3D) echocardiography with multiplanar reconstruction (MPR) is used clinically to quantify the mitral annulus. MPR images are, however, presented on a two-dimensional screen, calling into question their accuracy. An alternative to MPR is an autostereoscopic holographic display that enables in-depth visualization of 3D echocardiographic data without the need for special glasses. The aim of this study was to validate an autostereoscopic display using sonomicrometry as a gold standard. METHODS: In 11 anesthetized open-chest pigs, sonomicrometric crystals were placed along the mitral annulus and near the left ventricular apex. High-fidelity catheters measured left atrial and ventricular pressures. Adjustments of pre- and afterload were done by constriction of the inferior vena cava and the ascending aorta, respectively. Three-dimensional epicardial echocardiography was obtained from an apical view and converted to the autostereoscopic display. A 3D virtual semitransparent annular surface (VSAS) was generated to measure commissure width (CW), septal-lateral length, area of the mitral annular surface, nonplanarity angle, and the annular height-to-commissure width ratio in mid-systole and late diastole. RESULTS: Mitral annular measurements from the 3D VSAS derived from the 3D echocardiographic images and autostereoscopic display correlated well with sonomicrometry over a range of loading conditions: CW length (r = 0.98, P < .00001), septal-lateral length (r = 0.98, P < .00001), annular surface area (r = 0.93, P < .001), nonplanarity angle (r = 0.87, P < .001), and annular height-to-commissure width ratio (r = 0.85, P < .01). The 3D VSAS showed better agreement with the sonomicrometric measurements compared with MPR. CONCLUSIONS: Mitral annular measurements using 3D VSAS correlate well with sonomicrometry over a range of loading conditions and may represent a powerful tool for noninvasive quantification of mitral annular dynamics.

Karl Viktor Hall: From In Situ Vein Bypass to the Tilting Disc Heart Valve Prosthesis.

In 1977, Karl Viktor Hall implanted a novel tilting disc heart valve prosthesis at Rikshospitalet in Oslo, Norway. The Medtronic-Hall valve was known for its excellent durability and low thrombogenicity. Hall popularized the use of the great saphenous vein in situ as an arterial shunt in the 1960s, made a metal stripper to lyse vein valves, and introduced electromagnetic flowmeters in vascular surgery. He performed the first coronary artery bypass graft in Scandinavia in 1969. Under his leadership the first heart transplantation and the first heart-lung transplantation were performed in Scandinavia by his successor Tor Frøysaker in 1983 and 1986, respectively.