Left ventricular ejection fraction using a simplified wall motion score based on mid-parasternal short axis and apical four-chamber views for non-cardiologists.

BACKGROUND: There is a need for a convenient, yet reliable method to assess left ventricular ejection fraction (LVEF) with point-of-care ultrasound study (POCUS). We aim to validate a novel and simplified wall motion score LVEF based on the analysis of a simplified combination of echocardiographic views. METHODS: In this retrospective study, transthoracic echocardiograms of randomly selected patients were analysed by the standard 16-segments wall motion score index (WMSI) to derive the reference semi-quantitative LVEF. To develop our semi-quantitative simplified-views method, a limited combination of imaging views and only 4 segments per view were tested: (1) A combination of the three parasternal short-axis views (PSAX BASE, MID-, APEX); (2) A combination of the three apical views (apical 2-chamber, 3-chamber and 4-chamber) and (3) A more limited combination of PSAX-MID and apical 4-chamber is called the MID-4CH. Global LVEF is obtained by averaging segmental EF based on contractility (normal = 60%, hypokinesia = 40%, and akinesia = 10%). Accuracy of the novel semi-quantitative simplified-views WMS method compared to the reference WMSI was evaluated using Bland-Altman analysis and correlation was assessed in both emergency physicians and cardiologists. RESULTS: In the 46 patients using the 16 segments WMSI method, the mean LVEF was 34 ± 10%. Among the three combinations of the two or three imaging views analysed, the MID-4CH had the best correlation with the reference method (r2 = 0.90) with very good agreement (mean LVEF bias = - 0.2%) and precision (± 3.3%). CONCLUSIONS: Cardiac POCUS by emergency physicians and other non-cardiologists is a decisive therapeutic and prognostic tool. A simplified semi-quantitative WMS method to assess LVEF using the easiest technically achievable combination of mid-parasternal and apical four-chamber views provides a good approximative estimate for both non-cardiologist emergency physicians and cardiologists.

Hyperacute multi-organ thromboembolic storm in COVID-19: a case report.

Acute viral pneumonia, hypoxemic respiratory failure and severe inflammatory response are hallmarks of severe coronavirus disease 2019 (COVID-19). The COVID-19-associated inflammatory state may further lead to symptomatic thromboembolic complications despite prophylaxis. We report a 66-year-old female patient with post-mortem diagnosis of COVID-19 who presented progressive livedo racemosa, acute renal failure and myocardial injury, as well as an absence of respiratory symptoms. Transthoracic echocardiography showed severe spontaneous echo contrast in the right cardiac chambers and right-sided cardiac overload presumed to result from pulmonary microvascular thrombosis or embolism. D-dimer levels were increased. The patient developed an acute ischemic stroke and died 2 days following presentation despite therapeutic anticoagulation. Her predominantly thromboembolic presentation supports the concept of coronavirus infection of endothelial cells and hypercoagulability, or COVID-19 endotheliitis. The case we report highlights that COVID-19-associated hyperacute multi-organ thromboembolic storm may precede or present disproportionately to respiratory involvement.

Same day discharge after transcatheter aortic valve replacement: Are we there yet?

Early discharge after transcatheter aortic valve replacement (TAVR) has been increasingly reported, and is now becoming routinely performed in experienced TAVR centers. However, to the best of our knowledge, no case has been described where a patient was safely discharged on the same the day of the procedure. This report will present the case of a patient who underwent a successful transfemoral TAVR and was safely discharged home the same day. Specific requirements and criteria are proposed to ensure the safety of this approach.

Cardiotoxicity due to chemotherapy: role of cardiac imaging.

The identification of patients at risk of cardiac toxicity (cardiotoxicity) from cancer therapy is challenging. There is an increasing focus on early detection of cardiotoxicity such that interventions can be instituted to prevent advanced heart failure. Clinical risk prediction tools are limited and clinical symptoms are not specific. Direct assessment of myocardial function before and during cancer treatment using cardiac imaging appears to be an objective method to identify patients at risk. Although, multiple imaging modalities and measures of cardiac function are available, the best modality or the optimal measure of function is unknown. Measurement of left ventricular ejection fraction is most commonly used; however, growing literature suggests that it is inadequate for the detection of early cardiac injury. Other measures include left ventricular diastolic function, myocardial deformation, and myocardial tissue characterization. This review will provide an overview of the clinically available measures for the assessment of cardiotoxicity.

Two-dimensional transthoracic measure of mitral annulus in mitral valve prolapse and moderate to severe regurgitation: a method comparison analysis with three-dimensional transesophageal echocardiography.

BACKGROUND: Mitral annulus (MA) area is derived during transthoracic echocardiography (TTE) assuming of a circular shape using the MA diameter from the apical 4 chamber (A4c) view. Since the MA is not a circular structure, we hypothesized that an elliptical model using parasternal long-axis (PLAX) and apical 2 chamber (A2c) view measured MA diameters would have better agreement with 3-dimensional transesophageal echocardiography (3D TEE) measured MA in degenerative mitral valve disease (DMVD). METHODS: Seventy-six patients with moderate-to-severe DMVD had 2D TTE and 3D TEE performed. MA area was measured retrospectively using semi-automatic modeling of 3D data (3D TEEsa) and considered as the reference method. MA diameters were measured using different 2D TTE views. MA area was calculated using assumptions of a circular or an elliptical shape. 2D TTE derived and 3D TEEsa. MA areas were compared using linear regression and Bland-Altman analysis. RESULTS: The median MA area measured at 3D TEEsa was 1,386 (1,293-1,673) mm2. With 2D TTE, the circular model using A4c view diameter resulted in a small systematic underestimation of MA area (6%), while the elliptical model using PLAX and A2c diameters resulted in 25% systematic underestimation. The standard deviations of the distributions of inter-method differences were wide for all 2D TTE methods (265-289 mm2) when compared to 3D TEEsa, indicating imprecision. CONCLUSIONS: When compared with 3D TEEsa modeling of the MA as the reference, the assumption of a circular shape using A4c TTE view diameter was the method with the least systematic error to assess MA area in DMVD and moderate to severe regurgitation.

Automated and semi-automated 3D echocardiographic software for aortic annulus sizing in transcatheter aortic valve implantation helps bridge the gap between expert and novice operators.

3D-transesophageal echocardiography (3D-TEE) is an alternative to multidetector row computed tomography (MDCT) for aortic annulus (AoA) sizing in preparation for Transcatheter aortic valve implantation (TAVI). We aim to evaluate how the fully automated (auto) and semi-automated (SA) TEE methods perform compared to conventional manual TEE method and the gold standard MDCT for annulus sizing both in expert and novice operators. In this prospective cohort study, eighty-nine patients with severe aortic stenosis underwent multimodality imaging with 3D-TEE and MDCT. Annular measurements were collected by expert echocardiographers using 3D auto, SA and manual methods and compared to MDCT. A novice in the field of echocardiography retrospectively measured the AoA for all patients using the same methods. TEE measurements, independently of the method used, had good to very good agreement to MDCT. They significantly underestimated aortic annular area and circumference vs. MDCT with the auto method underestimating it the most and the manual method the least (6.5% and 1.3% respectively for area and circumference). For experts, the manual TEE method offered the least systematic bias while the SA method had narrower limits of agreement (LOA). For the novice operator, SA method provided the least bias and narrower LOA vs. MDCT. There is good agreement between novice and experts for all 3 TEE methods but better agreement with auto and SA methods as opposed to manual one. Our study supports the use of 3D-TEE as a complementary method to MDCT for aortic annular sizing. The newer auto and SA software, that requires minimal operator intervention, is an easy to use, reliable and reproducible tool for aortic annulus sizing for experienced operators, and especially less experienced ones.

Prognostic Value of Preprocedural LV Global Longitudinal Strain for Post-TAVR-Related Morbidity and Mortality: A Meta-Analysis.

BACKGROUND: Left ventricular ejection fraction (LVEF) demonstrates limited prognostic value for post-transcatheter aortic valve replacement (TAVR) outcomes. Evidence regarding the potential role of left ventricular global longitudinal strain (LV-GLS) in this setting is inconsistent. OBJECTIVES: The aim of this systematic review and meta-analysis of aggregated data was to evaluate the prognostic value of preprocedural LV-GLS for post-TAVR-related morbidity and mortality. METHODS: The authors searched PubMed, Embase, and Web of Science for studies investigating the association between preprocedural 2-dimensional speckle-tracking-derived LV-GLS and post-TAVR clinical outcomes. An inversely weighted random effects meta-analysis was adopted to investigate the association between LV-GLS vs primary (ie, all-cause mortality) and secondary (ie, major cardiovascular events [MACE]) post-TAVR outcomes. RESULTS: Of the 1,130 identified records, 12 were eligible, all of which had a low-to-moderate risk of bias (Newcastle-Ottawa scale). On average, 2,049 patients demonstrated preserved LVEF (52.6% ± 1.7%), but impaired LV-GLS (-13.6% ± 0.6%). Patients with a lower LV-GLS had a higher all-cause mortality (pooled HR: 2.01; 95% CI: 1.59-2.55) and MACE (pooled odds ratio [OR]: 1.26; 95% CI: 1.08-1.47) risk compared with patients with higher LV-GLS. In addition, each percentage point decrease of LV-GLS (ie, toward 0%) was associated with an increased mortality (HR: 1.06; 95% CI: 1.04-1.08) and MACE risk (OR: 1.08; 95% CI: 1.01-1.15). CONCLUSIONS: Preprocedural LV-GLS was significantly associated with post-TAVR morbidity and mortality. This suggests a potential clinically important role of pre-TAVR evaluation of LV-GLS for risk stratification of patients with severe aortic stenosis. (Prognostic value of left ventricular global longitudinal strain in patients with aortic stenosis undergoing Transcatheter Aortic Valve Implantation: a meta-analysis; CRD42021289626).

Right ventricular ejection fraction with cardiac magnetic resonance using a wall motion score.

BACKGROUND: The volumetric method in cardiac magnetic resonance (CMR), the reference standard for right ventricular ejection fraction (RVEF), requires expertise because of the complex right ventricular geometry and anatomical landmarks. AIM: The aim of our retrospective study was to describe a new method to evaluate RVEF based on wall motion score index (WMSI) in CMR. METHODS: Visual assessment of wall motion was performed using an eight-segment model (normokinesia=1, hypokinesia=2, akinesia=3). Correlation between WMSI (WMS/8) and the reference volumetric RVEF was analysed. A regression equation was derived to convert the WMSI into RVEF. The accuracy of CMR WMSI-derived RVEF compared with CMR volumetric RVEF was evaluated using Bland-Altman analysis. RESULTS: In the 112 patients using the volumetric method, the mean RVEF was 48±14%. Fifty-nine patients had normal RV kinetics (WMSI=1), which corresponded to a volumetric RVEF of 56% (standard deviation 7%; range 43-76%). CMR WMSI showed a strong correlation with CMR volumetric RVEF (Spearman's Rho=-0.69). A regression equation was created: RVEF=80-22×WMSI. Overall, the WMSI-derived RVEF resulted in good agreement with the CMR volumetric RVEF (mean bias-3%, standard deviation±7.5%). In addition, using a WMSI cut-off of≥1.5 was highly accurate (92%) to predict a reference RVEF of˂45%, an important prognostic indicator in CMR. CONCLUSIONS: Our results suggest that using the WMS in CMR (eight-segment) to estimate RVEF is accurate, and correlates well with the volumetric method. A WMSI≥1.5 is optimal to categorize patients in the higher-risk subset of CMR RVEF˂45%.

Right ventricular dysfunction in neurologically deceased organ donors: An observational study in a tertiary-care organ donor referral centre.

PURPOSE: Right ventricular RV dysfunction among transplant recipients correlates with transplant outcome, but its frequency in donors is unknown. The purpose of this study was to describe the epidemiology of RV dysfunction in potential heart donors." METHODS: In a seven-year retrospective study of potential heart donors, we explored the incidence of RV dysfunction as observed on echocardiography and explored the association of four distinct factors with RV dysfunction: brain injury diagnosis, thoracic trauma, vasopressin infusion and left ventricular (LV) dysfunction. RESULTS: All 123 potential heart donors underwent echocardiography: 55 had RV dysfunction (44.7%). Fourty-one (33.3%) had LV dysfunction. Isolated RV dysfunction was present in 27 subjects (22%). LV dysfunction was the only factor significantly associated with RV dysfunction (OR = 4.6 (95% CI 1.9-11.4)). We observed no difference in heart acceptance between subjects with or without RV dysfunction. CONCLUSION: We observed a high frequency of RV dysfunction in a sample of potential heart donors. However, the temporal evolution of RV dysfunction, the hemodynamic predictors of RV dysfunction, as well the link between donor RV dysfunction and recipient outcomes need to be assessed with further prospective studies.

A Study of the interaction of HEK-293 cells with streamline chelating adsorbent in expanded bed operation.

Expanded bed adsorption (EBA) is an efficient protein purification process reducing time and steps of downstream processing (DSP) since nonclarified culture media can be processed directly without prior treatments such as filtration or centrifugation. However, cells and debris can interact with the adsorbent and affect bed stability as well as purification performance. To optimize EBA operating conditions these biomass/adsorbent interactions have to be understood and characterized. The adsorption of Human Embryonic Kidney cells (HEK 293) on unprimed and nickel-primed metal affinity adsorbent was studied in a closed loop EBA setup. With the unprimed adsorbent, the overall level of interaction observed was nonsignificant. With the nickel-primed adsorbent and an initial cell concentration ranging from 0.08 x 10(6) to 0.2 x 10(6) cells/mL, biomass/adsorbent interaction was found to be moderate and the adsorption apparent first-order kinetic rate constant was determined to be k = 0.009 to 0.011 min(-1).

Severe bradyarrhythmia linked to left atrial dysfunction in Fabry disease-A cross-sectional study.

BACKGROUND: Fabry disease (FD) is a lysosomal storage disorder caused by an enzymatic deficiency. Conduction abnormalities and bradyarrhythmias are common and can occur prior to the onset of left ventricular (LV) hypertrophy. We aimed to describe the clinical, electrocardiographic and echocardiographic, including left atrial (LA) function, determinants of bradyarrhythmic events in FD. HYPOTHESIS: Bradyarrhythmic events are frequent in patients with FD and are associated with LA dysfunction. METHODS: We designed a cross-sectional study that includes 53 FD patients (mean age, 45 years; 42% male). Clinical characteristics and electrocardiographic and echocardiographic data were collected. LA function was measured using biplane volumes and 2D speckle-tracking echocardiography. Bradyarrhythmic events were defined as pause of more than 2 seconds (sinus pause or atrioventricular block) recorded on Holter, severe bradycardia (≤ 40 bpm on ECG) or implantation of a permanent pacemaker. RESULTS: Six (11%) patients had installation of a pacemaker, 4 (8%) patients had cardiac pause and 2 (4%) patients had an episode of severe bradycardia. Patients with bradyarrhythmic events were older and had a lower resting heart rate. On echocardiography, a significantly higher LV mass, a lower LV ejection fraction, and a more affected LA reservoir function were found in those with bradyarrhythmic events. Patients also experienced tachyarrhythmias frequently. Atrial fibrillation occurred in 11 (21%) patients and ventricular tachycardia in 4 (8%) patients. CONCLUSIONS: Bradyarrhythmia are common manifestations of cardiac involvement in FD. Age, LV mass, LV ejection fraction and LA reservoir dysfunction can be useful markers associated with bradyarrhythmia.

Assessment of LVEF using a new 16-segment wall motion score in echocardiography.

BACKGROUND: Simpson biplane method and 3D by transthoracic echocardiography (TTE), radionuclide angiography (RNA) and cardiac magnetic resonance imaging (CMR) are the most accepted techniques for left ventricular ejection fraction (LVEF) assessment. Wall motion score index (WMSI) by TTE is an accepted complement. However, the conversion from WMSI to LVEF is obtained through a regression equation, which may limit its use. In this retrospective study, we aimed to validate a new method to derive LVEF from the wall motion score in 95 patients. METHODS: The new score consisted of attributing a segmental EF to each LV segment based on the wall motion score and averaging all 16 segmental EF into a global LVEF. This segmental EF score was calculated on TTE in 95 patients, and RNA was used as the reference LVEF method. LVEF using the new segmental EF 15-40-65 score on TTE was compared to the reference methods using linear regression and Bland-Altman analyses. RESULTS: The median LVEF was 45% (interquartile range 32-53%; range from 15 to 65%). Our new segmental EF 15-40-65 score derived on TTE correlated strongly with RNA-LVEF (r = 0.97). Overall, the new score resulted in good agreement of LVEF compared to RNA (mean bias 0.61%). The standard deviations (s.d.s) of the distributions of inter-method difference for the comparison of the new score with RNA were 6.2%, indicating good precision. CONCLUSION: LVEF assessment using segmental EF derived from the wall motion score applied to each of the 16 LV segments has excellent correlation and agreement with a reference method.

Potential shift from coronary bypass surgery to percutaneous coronary intervention for multivessel disease and its economic impact in the drug-eluting stent era.

BACKGROUND: Drug-eluting stents (DES) may promote percutaneous coronary intervention (PCI) procedures in patients traditionally referred for coronary artery bypass graft (CABG) surgery and may save money. OBJECTIVES: The purpose of the present study was to quantify the potential shift from CABG surgery to multivessel PCI in the DES era and to model the economic consequences. METHODS: Based on predefined criteria, the feasibility of PCI was evaluated in patients with multivessel coronary artery disease who underwent CABG surgery before the availability of DES at the Centre Hospitalier de l'Université de Montréal's Notre-Dame Hospital (Montreal, Quebec). Modelling was used to evaluate the potential cost savings using multivessel PCI instead of CABG surgery. Equal one-year outcomes in both groups were assumed, with the exception of a 10% repeat revascularization (RR) rate in the DES group and a 4% RR rate in the CABG group. The impact of those assumptions was evaluated using 1000 Monte Carlo simulations. RESULTS: The authors retrospectively evaluated that, of 289 patients who underwent CABG without concomitant valve surgery between January and December 2003, only 22 patients (8%) were good candidates for multivessel DES implantation. The procedures would have involved an average of 3.6 DES per patient. The average cost per revascularization procedure was $14,402 with surgery and $11,220 for multivessel DES implantation (using $2,200 DES), leading to a savings of $3,182 per patient. However, after including RR procedures, PCI would only have been associated with savings of $812 per surgery avoided. Monte Carlo analysis revealed that surgery may be less expensive than PCI in 36% of patients. CONCLUSIONS: Most patients who underwent CABG surgery in 2003 were retrospectively judged to be ineligible for multivessel PCI with DES. In the rare eligible patient, multivessel PCI with DES is not expected to produce savings to health care costs in Canada unless the DES purchase cost continues to decrease.

Early Hemodynamic Results in Patients With Small Aortic Annulus After Aortic Valve Replacement.

OBJECTIVE: Patients with a small aortic annulus (≤21 mm) have an increased risk of patient-prosthesis mismatch after valve replacement. The aim of this study was to compare the early hemodynamic performance of the balloon-expandable transaortic valve implantation Edwards system (SAPIEN) and the sutureless Perceval prostheses. METHODS: Fifty patients underwent transcatheter aortic valve implantation, and 113 patients underwent sutureless aortic valve replacement. Mean ± SD aortic annulus diameter was 19.7 ± 1 mm, with no significant difference between groups. SAPIEN valve size was 23 mm in 40 patients (80%) and 26 mm in 10 patients (20%). Perceval valve size was small in 45 patients (40%), medium in 62 patients (55%), and large in 6 patients (5%). Transthoracic Doppler echocardiographic images were collected at baseline and before discharge. RESULTS: There were no significant difference in predischarge effective orifice area (SAPIEN: 1.5 ± 0.5 cm and Perceval: 1.48 ± 0.34 cm, P = 0.58) and indexed effective orifice areas (SAPIEN: 0.93 ± 0.32 cm/m and Perceval: 0.88 ± 0.22 cm/m, P = 0.42). Predischarge mean ± SD transaortic gradient was lower with the SAPIEN than with Perceval valves (12 ± 6 and 17 ± 6 mm Hg, respectively, P < 0.001). Rates of moderate and severe prosthesis-patient mismatch were similar (SAPIEN: 44% and 10% and Perceval: 50% and 14%, P = 0.53 and 0.75, respectively). There were no moderate-severe paravalvular leaks. CONCLUSIONS: Although indexed effective orifice areas were similar, transcatheter aortic valve implantation with the balloon-expandable SAPIEN system yielded lower predischarge transaortic mean gradients than the surgically implanted Perceval, in patients with a small annulus.

Impaired Left Atrial Function in Fabry Disease: A Longitudinal Speckle-Tracking Echocardiography Study.

BACKGROUND: Fabry disease (FD) is characterized by the accumulation of sphingolipids in multiple organs, including the left atrium. It is uncertain if the left atrial (LA) reservoir, conduit, and contractile functions evaluated by speckle-tracking echocardiography are affected in Fabry cardiomyopathy and whether enzyme replacement therapy can improve LA function. METHODS: In this retrospective cohort study, LA strain, strain rates, and phasic LA volumes were studied in 50 patients with FD and compared with values in 50 healthy control subjects. RESULTS: All three LA phasic functions were altered. Peak positive strain (reservoir function) was 38.9 ± 14.9% versus 46.5 ± 10.9% (P = .004), and late diastolic strain (contractile function) was 12.6 ± 5.9% versus 15.6 ± 5.3% (P = .010). In 15 patients who started enzyme replacement therapy during the study, most of the LA parameters improved at 1-year follow-up (peak positive strain from 32.0 ± 13.5% to 38.0 ± 13.5%, P = .006), whereas there was a trend toward deterioration in 15 patients who never received treatment (peak positive strain from 47.3 ± 10.8% to 41.3 ± 9.3%, P = .058). Nine patients with FD (21%) experienced new-onset atrial fibrillation or stroke during 4-year follow-up. By univariate analysis, peak positive strain and early diastolic strain demonstrated significant associations with clinical events, surpassing conventional echocardiographic parameters and clinical characteristics. CONCLUSIONS: LA reservoir, conduit, and contractile functions by speckle-tracking echocardiography were all affected in FD. Enzyme replacement therapy improved LA function. LA strain parameters were associated with atrial fibrillation and stroke.

Left Atrial Phasic Function and Its Association With Atrial Fibrillation in Patients After Transcatheter Aortic Valve Implantation.

BACKGROUND: Left atrial (LA) size is a marker of prognosis in severe aortic stenosis (AS). The aims of this retrospective study were to assess the impact of transcatheter aortic valve implantation (TAVI) on the recovery of LA phasic function and to assess the relationship between LA function and new-onset atrial fibrillation (NAF) after TAVI. METHODS: In this retrospective cohort study, LA function was measured using biplane volumes and 2-dimensional (2D) speckle tracking echocardiography (STE) in 52 patients (median age, 81 years) with severe AS before TAVI and at midterm follow-up. Twenty healthy individuals ≥ 75 years were used as controls. RESULTS: Before TAVI, the 3 phasic volumetric emptying fractions and all STE-derived parameters of LA function were significantly reduced. At 5 ± 3 months after TAVI, there was an improvement in LA reservoir and contractile function. However, LA phasic volumes and emptying fractions showed minimal changes. Fourteen patients had NAF in the early postprocedural period after TAVI. These patients experienced longer hospitalization (11 days vs 6 days; P = 0.002). By bivariable logistic regression analysis, the use of a transapical approach and the LA early diastolic strain rate (SR) before TAVI were significantly associated with NAF immediately after TAVI. CONCLUSIONS: Severe AS is associated with LA dysfunction. Intrinsic LA compliance and LA contractile properties by STE improved at midterm follow-up after TAVI. Preprocedural LA early diastolic SR may predict the development of NAF after TAVI pending confirmation by larger prospective evaluations.

Identifying conditions for inducible protein production in E. coli: combining a fed-batch and multiple induction approach.

BACKGROUND: In the interest of generating large amounts of recombinant protein, inducible systems have been studied to maximize both the growth of the culture and the production of foreign proteins. Even though thermo-inducible systems were developed in the late 1970's, the number of studies that focus on strategies for the implementation at bioreactor scale is limited. In this work, the bacteriophage lambda PL promoter is once again investigated as an inducible element but for the production of green fluorescent protein (GFP). Culture temperature, induction point, induction duration and number of inductions were considered as factors to maximize GFP production in a 20-L bioreactor. RESULTS: It was found that cultures carried out at 37 degrees C resulted in a growth-associated production of GFP without the need of an induction at 42 degrees C. Specific production was similar to what was achieved when separating the growth and production phases. Shake flask cultures were used to screen for desirable operating conditions. It was found that multiple inductions increased the production of GFP. Induction decreased the growth rate and substrate yield coefficients; therefore, two time domains (before and after induction) having different kinetic parameters were created to fit a model to the data collected. CONCLUSION: Based on two batch runs and the simulation of culture dynamics, a pre-defined feeding and induction strategy was developed to increase the volumetric yield of a temperature regulated expression system and was successfully implemented in a 20-L bioreactor. An overall cell density of 5.95 g DW l(-1) was achieved without detriment to the cell specific production of GFP; however, the production of GFP was underestimated in the simulations due to a significant contribution of non-growth associated product formation under limiting nutrient conditions.

Transcatheter Aortic Valve Replacement in a Patient With a Previous Bioprosthetic Mitral Valve Replacement: Report of a Delayed Fatal Interaction.

We report on a man with bioprosthetic mitral valve perforation who presented late after transcatheter aortic valve replacement with a balloon-expandable transcatheter heart valve (THV). The protrusion of the commissural strut of the bioprosthetic mitral valve coupled with the low implanted THV resulted in repetitive trauma leading to rupture of a mitral leaflet. Potential preventive strategies are discussed. This case illustrates the importance of preprocedural imaging screening and cautious THV deployment in patients with a bioprosthetic mitral valve.

Impact of Prosthesis-Patient Mismatch on Left Ventricular Myocardial Mechanics After Transcatheter Aortic Valve Replacement.

BACKGROUND: The aim of this study was to compare left ventricular (LV) remodeling using myocardial strain between patients with severe aortic stenosis (AS) treated with transcatheter aortic valve replacement (TAVR) with and without prosthesis-patient mismatch (PPM). METHODS AND RESULTS: In a retrospective study, speckle-tracking echocardiography was used to measure global longitudinal strain (GLS) and strain rate (GLSR), circumferential strain, and rotation before and at mid-term follow-up post-TAVR. Moderate and severe PPM were defined as an effective orifice area ≤0.85 and <0.65 cm(2)/m(2), respectively. A total of 102 patients (median age, 83 years [77-88]) with severe AS were included. At 6±3 months post-TAVR, moderate and severe PPM were found in 32 (31%) and 9 (9%) patients. Patients without PPM had a significant regression in LV mass (from 134±41 to 119±38 g/m(2); P=0.001) at follow-up whereas those with PPM did not. There was a significant improvement in LV GLS (-12.8±4.0 to -14.3±4.3%; P=0.01), GLSR (-0.61±0.20 to -0.73±0.25 second(-1); P<0.001), and early diastolic strain rate (0.52±0.20 to 0.64±0.20 second(-1); P<0.001) in patients without PPM, but not in those with PPM. After adjustment for pre-TAVR ejection fraction and post-TAVR aortic regurgitation, patients without PPM had greater improvement in LV longitudinal strain parameters compared to those with PPM. After a median follow-up of 46.1 months (interquartile range, 35.4-60.8), there was no difference in survival between patients with and without PPM. CONCLUSIONS: TAVR was associated with an incidence of PPM of 40%. Greater reverse LV remodeling using myocardial strain was evident in patients without PPM compared to PPM. Presence of PPM was not associated with mortality.