Development and validation of a prediction model for early mortality after transcatheter aortic valve implantation (TAVI) based on the Netherlands Heart Registration (NHR): The TAVI-NHR risk model.

BACKGROUND: The currently available mortality prediction models (MPM) have suboptimal performance when predicting early mortality (30-days) following transcatheter aortic valve implantation (TAVI) on various external populations. We developed and validated a new TAVI-MPM based on a large number of predictors with recent data from a national heart registry. METHODS: We included all TAVI-patients treated in the Netherlands between 2013 and 2018, from the Netherlands Heart Registration. We used logistic-regression analysis based on the Akaike Information Criterion for variable selection. We multiply imputed missing values, but excluded variables with >30% missing values. For internal validation, we used ten-fold cross-validation. For temporal (prospective) validation, we used the 2018-data set for testing. We assessed discrimination by the c-statistic, predicted probability accuracy by the Brier score, and calibration by calibration graphs, and calibration-intercept and calibration slope. We compared our new model to the updated ACC-TAVI and IRRMA MPMs on our population. RESULTS: We included 9144 TAVI-patients. The observed early mortality was 4.0%. The final MPM had 10 variables, including: critical-preoperative state, procedure-acuteness, body surface area, serum creatinine, and diabetes-mellitus status. The median c-statistic was 0.69 (interquartile range [IQR] 0.646-0.75). The median Brier score was 0.038 (IQR 0.038-0.040). No signs of miscalibration were observed. The c-statistic's temporal-validation was 0.71 (95% confidence intervals 0.64-0.78). Our model outperformed the updated currently available MPMs ACC-TAVI and IRRMA (p value < 0.05). CONCLUSION: The new TAVI-model used additional variables and showed fair discrimination and good calibration. It outperformed the updated currently available TAVI-models on our population. The model's good calibration benefits preprocedural risk-assessment and patient counseling.

Investigating the physiology of normothermic ex vivo heart perfusion in an isolated slaughterhouse porcine model used for device testing and training.

BACKGROUND: The PhysioHeart™ is a mature acute platform, based isolated slaughterhouse hearts and able to validate cardiac devices and techniques in working mode. Despite perfusion, myocardial edema and time-dependent function degradation are reported. Therefore, monitoring several variables is necessary to identify which of these should be controlled to preserve the heart function. This study presents biochemical, electrophysiological and hemodynamic changes in the PhysioHeart™ to understand the pitfalls of ex vivo slaughterhouse heart hemoperfusion. METHODS: Seven porcine hearts were harvested, arrested and revived using the PhysioHeart™. Cardiac output, SaO2, glucose and pH were maintained at physiological levels. Blood analyses were performed hourly and unipolar epicardial electrograms (UEG), pressures and flows were recorded to assess the physiological performance. RESULTS: Normal cardiac performance was attained in terms of mean cardiac output (5.1 ± 1.7 l/min) and pressures but deteriorated over time. Across the experiments, homeostasis was maintained for 171.4 ± 54 min, osmolarity and blood electrolytes increased significantly between 10 and 80%, heart weight increased by 144 ± 41 g, free fatty acids (- 60%), glucose and lactate diminished, ammonia increased by 273 ± 76% and myocardial necrosis and UEG alterations appeared and aggravated. Progressively deteriorating electrophysiological and hemodynamic functions can be explained by reperfusion injury, waste product intoxication (i.e. hyperammonemia), lack of essential nutrients, ion imbalances and cardiac necrosis as a consequence of hepatological and nephrological plasma clearance absence. CONCLUSIONS: The PhysioHeart™ is an acute model, suitable for cardiac device and therapy assessment, which can precede conventional animal studies. However, observations indicate that ex vivo slaughterhouse hearts resemble cardiac physiology of deteriorating hearts in a multi-organ failure situation and signalize the need for plasma clearance during perfusion to attenuate time-dependent function degradation. The presented study therefore provides an in-dept understanding of the sources and reasons causing the cardiac function loss, as a first step for future effort to prolong cardiac perfusion in the PhysioHeart™. These findings could be also of potential interest for other cardiac platforms.

Aortic valve stenosis and aortic diameters determine the extent of increased wall shear stress in bicuspid aortic valve disease.

BACKGROUND: Use of 4-dimensional flow magnetic resonance imaging (4D-flow MRI) derived wall shear stress (WSS) heat maps enables identification of regions in the ascending aorta with increased WSS. These regions are subject to dysregulation of the extracellular matrix and elastic fiber degeneration, which is associated with aortic dilatation and dissection. PURPOSE: To evaluate the effect of the presence of aortic valve stenosis and the aortic diameter on the peak WSS and surface area of increased WSS in the ascending aorta. STUDY TYPE: Prospective. SUBJECTS: In all, 48 bicuspid aortic valve (BAV) patients (38.1 ± 12.4 years) and 25 age- and gender-matched healthy individuals. FIELD STRENGTH/SEQUENCE: Time-resolved 3D phase contrast MRI with three-directional velocity encoding at 3.0T. ASSESSMENT: Peak systolic velocity, WSS, and aortic diameters were assessed in the ascending aorta and 3D heat maps were used to identify regions with elevated WSS. STATISTICAL TESTS: Comparisons between groups were performed by t-tests. Correlations were investigated by univariate and multivariate regression analysis. RESULTS: Elevated WSS was present in 15 ± 11% (range; 1-35%) of the surface area of the ascending aorta of BAV patients with aortic valve stenosis (AS) (n = 10) and in 6 ± 8% (range; 0-31%) of the ascending aorta of BAV patients without AS (P = 0.005). The mid-ascending aortic diameter negatively correlated with the peak ascending aortic WSS (R = -0.413, P = 0.004) and the surface area of elevated WSS (R = -0.419, P = 0.003). Multivariate linear regression analysis yielded that the height of peak WSS and the amount of elevated WSS depended individually on the presence of aortic valve stenosis and the diameter of the ascending aorta. DATA CONCLUSION: The extent of increased WSS in the ascending aorta of BAV patients depends on the presence of aortic valve stenosis and aortic dilatation and is most pronounced in the presence of AS and a nondilated ascending aorta. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2018;48:522-530.

Totally thoracoscopic ablation for atrial fibrillation: a systematic safety analysis.

Aims: Thoracoscopic surgical ablation has evolved into a successful strategy for symptomatic atrial fibrillation (AF) refractory to other therapy. More widespread referral is limited by the lack of information on potential complications. Our aim was to systematically evaluate 30-day complications of totally thoracoscopic surgical ablation. Methods and results: We retrospectively studied consecutive patients undergoing totally thoracoscopic surgical ablation at a referral centre in the Netherlands (2007-2016). Patients received pulmonary vein isolation, with additional lesion lines as needed, and left atrial appendage exclusion. The primary outcomes were freedom from any complications and freedom from irreversible complications at 30-days. Secondary outcomes included intra- and post-operative complications according to severity. Included were 558 patients with median age 62 years (interquartile range 56-68 years), 70% male and 53% with a previous failed catheter ablation. The cohort consisted of 43% paroxysmal AF, 47% persistent AF, and 10% long-standing persistent AF. Freedom from any 30-day complication was 88.2%, and from complications with life-long affecting consequences 97.5%. The intra-operative complication rate was 2.3% with no strokes or death observed. The median hospital length of stay was 4 days. The percentage of patients with major and minor complications at 30-days was 3.2% and 8.1%, respectively, with one patient dying of an ischaemic stroke. The only patient groups with excess complications were women aged ≥70 years and patients with a history of congestive heart failure. Conclusions: Totally thoracoscopic ablation is associated with a low complication rate in a referral centre and may be a useful alternative to other rhythm control strategies.

Assessment of Cardiac Device Position on Supine Chest Radiograph in the ICU: Introduction and Applicability of the Aortic Valve Location Ratio.

OBJECTIVES: The use of intracardiac assist devices is expanding, and correct position of these devices is required for optimal functioning. The aortic valve is an important landmark for positioning of those devices. It would be of great value if the device position could be easily monitored on plain supine chest radiograph in the ICU. We introduce a ratio-based tool for determination of the aortic valve location on plain supine chest radiograph images, which can be used to evaluate intracardiac device position. DESIGN: Retrospective observational study. SETTING: Large academic medical center. PATIENTS: Patients admitted to the ICU and supported by an intracardiac assist device. INTERVENTIONS: We developed a ratio to determine the aortic valve location on supine chest radiograph images. This ratio is used to assess the position of a cardiac assist device and is compared with echocardiographic findings. MEASUREMENTS AND MAIN RESULTS: Supine anterior-posterior chest radiographs of patients with an aortic valve prosthesis (n = 473) were analyzed to determine the location of the aortic valve. We calculated several ratios with the potential to determine the position of the aortic valve. The aortic valve location ratio, defined as the distance between the carina and the aortic valve, divided by the thoracic width, was found to be the best performing ratio. The aortic valve location ratio determines the location of the aortic valve caudal to the carina, at a distance of 0.25 ± 0.05 times the thoracic width for male patients and 0.28 ± 0.05 times the thoracic width for female patients. The aortic valve location ratio was validated using CT images of patients with angina pectoris without known valvular disease (n = 95). There was a good correlation between cardiac device position (Impella) assessed with the aortic valve location ratio and with echocardiography (n = 53). CONCLUSIONS: The aortic valve location ratio enables accurate and reproducible localization of the aortic valve on supine chest radiograph. This tool is easily applicable and can be used for assessment of cardiac device position in patients on the ICU.

Baseline MDCT findings after prosthetic heart valve implantation provide important complementary information to echocardiography for follow-up purposes.

OBJECTIVES: Recent studies have proposed additional multidetector-row CT (MDCT) for prosthetic heart valve (PHV) dysfunction. References to discriminate physiological from pathological conditions early after implantation are lacking. We present baseline MDCT findings of PHVs 6 weeks post implantation. METHODS: Patients were prospectively enrolled and TTE was performed according to clinical guidelines. 256-MDCT images were systematically assessed for leaflet excursions, image quality, valve-related artefacts, and pathological and additional findings. RESULTS: Forty-six patients were included comprising 33 mechanical and 16 biological PHVs. Overall, MDCT image quality was good and relevant regions remained reliably assessable despite mild-moderate PHV-artefacts. MDCT detected three unexpected valve-related pathology cases: (1) prominent subprosthetic tissue, (2) pseudoaneurysm and (3) extensive pseudoaneurysms and valve dehiscence. The latter patient required valve surgery to be redone. TTE only showed trace periprosthetic regurgitation, and no abnormalities in the other cases. Additional findings were: tilted aortic PHV position (n = 3), pericardial haematoma (n = 3) and pericardial effusion (n = 3). Periaortic induration was present in 33/40 (83 %) aortic valve patients. CONCLUSIONS: MDCT allowed evaluation of relevant PHV regions in all valves, revealed baseline postsurgical findings and, despite normal TTE findings, detected three cases of unexpected, clinically relevant pathology. KEY POINTS: • Postoperative MDCT presents baseline morphology relevant for prosthetic valve follow-up. • 83 % of patients show periaortic induration 6 weeks after aortic valve replacement. • MDCT detected three cases of clinically relevant pathology not found with TTE. • Valve dehiscence detection by MDCT required redo valve surgery in one patient. • MDCT is a suitable and complementary imaging tool for follow-up purposes.

Functional decline of older patients 1 year after cardiothoracic surgery followed by intensive care admission: a prospective longitudinal cohort study.

BACKGROUND: there is a growing demand for cardiothoracic surgery in patients' aged ≥65 years. OBJECTIVE: : to explore which variables were independently associated with functional decline 12 months after cardiothoracic surgery followed by intensive care admission. DESIGN: prospective cohort study. SETTING: cardiothoracic unit of a university teaching hospital. SUBJECTS: a total of 356 elderly patients undergoing cardiothoracic surgery followed by intensive care unit admission. METHODS: functioning was assessed at hospital admission and 3 and 12 months after hospital discharge with the modified Katz activities of daily living (ADL) index. Data collection included demographics, surgical procedure, diagnosis, comorbidities, pre-morbid geriatric conditions and intensive care unit length of stay. Functional decline was defined as a one-point loss on the modified Katz ADL index score at 1 year compared with baseline functioning at hospital admission. Logistic regression analysis was performed to study the association between independent variables and functional decline. RESULTS: the 1-year mortality rate was 8.7% of which 4.8% was in-hospital mortality. The youngest group consisted of 295 patients (64% men; 72 ± 4 years), there were 61 octogenarians (56% men; 82 ± 2 years). One year after hospital discharge, younger patients demonstrated less functional decline (45 versus 56%, P < 0.001). Cognitive impairment, higher age, female gender, alcohol use, type of cardiac procedure and serum creatinine were independently associated with functional decline 1 year after discharge. CONCLUSIONS: the survival rates after cardiothoracic surgery were good, the rates of functional decline were substantial. These results suggest that studies on geriatric rehabilitation before and after surgery might be needed to overcome the decline in functioning.

Balancing Scaffold Degradation and Neo-Tissue Formation in In Situ Tissue Engineered Vascular Grafts.

An essential aspect of cardiovascular in situ tissue engineering (TE) is to ensure balance between scaffold degradation and neo-tissue formation. We evaluated the rate of degradation and neo-tissue formation of three electrospun supramolecular bisurea-based biodegradable scaffolds that differ in their soft-block backbone compositions only. Scaffolds were implanted as interposition grafts in the abdominal aorta in rats, and evaluated at different time points (t = 1, 6, 12, 24, and 40 weeks) on function, tissue formation, strength, and scaffold degradation. The fully carbonate-based biomaterial showed minor degradation after 40 weeks in vivo, whereas the other two ester-containing biomaterials showed (near) complete degradation within 6-12 weeks. Local dilatation was only observed in these faster degrading scaffolds. All materials showed to some extent mineralization, at early as well as late time points. Histological evaluation showed equal and non-native-like neo-tissue formation after total degradation. The fully carbonate-based scaffolds lagged in neo-tissue formation, presumably as its degradation was (far from) complete at 40 weeks. A significant difference in vessel wall contrast enhancement was observed by magnetic resonance imaging between grafts with total compared with minimal-degraded scaffolds.

Simulation of changes in myocardial tissue properties during left ventricular assistance with a rotary blood pump.

We considered a mathematical model to investigate changes in geometric and hemodynamic indices of left ventricular function in response to changes in myofiber contractility and myocardial tissue stiffness during rotary blood pump support. Left ventricular assistance with a rotary blood pump was simulated based on a previously published biventricular model of the assisted heart and circulation. The ventricles in this model were based on the one-fiber model that relates ventricular function to myofiber contractility and myocardial tissue stiffness. The simulations showed that indices of ventricular geometry, left ventricular shortening fraction, and ejection fraction had the same response to variations in myofiber contractility and myocardial tissue stiffness. Hemodynamic measures showed an inverse relation compared with geometric measures. Particularly, pulse pressure and arterial dP/dtmax increased when myofiber contractility increased, whereas increasing myocardial tissue stiffness decreased these measures. Similarly, the lowest pump speed at which the aortic valve remained closed increased when myofiber contractility increased and decreased when myocardial tissue stiffness increased. Therefore, simultaneous monitoring of hemodynamic parameters and ventricular geometry indirectly reflects the status of the myocardial tissue. The appropriateness of this strategy will be evaluated in the future, based on in vivo studies.

Peri-operative care in adults with congenital heart disease: room for improvement in after care.

BACKGROUND: Patient satisfaction with care has received little attention within the field of congenital heart disease. Our objective was to examine patient satisfaction with the care received when undergoing open-heart surgery in order to identify the best and worst aspects of peri-operative care. Moreover, we examined whether having contact with a specialised nurse in addition to usual care is associated with higher patient satisfaction levels. METHODS: Patient satisfaction was measured by the Satisfaction with Hospital Care Questionnaire, evaluating nine aspects of care by answering individual items and giving overall grades. A top 10 of the best and worst items was selected. Linear regression analyses were used to examine the relationship between having contact with a specialised nurse and patient satisfaction (9 grades), independent of patient characteristics--sex, age, educational level, and health status. RESULTS: Data were available for 75 patients. Grades ranged from 6.74 for "discharge and after care" to 8.18 for "medical care". In all, 21% of patients were dissatisfied with the clarity of the information about lifestyle adjustments given by the surgeon. However, patients who had contact with a specialised nurse were more satisfied with the provided information (B-coefficient is 0.497, p-value is 0.038), independent of patient characteristics. CONCLUSIONS: Patients were satisfied with the received care, although there is room for improvement, especially in discharge and after care and the clarity of the information provided by the surgeon. This gap in care can be compensated for by specialised nurses, as patients who were counselled by a specialised nurse were more satisfied with the provided information.

Outpatient treatment of worsening heart failure with intravenous diuretics: first results from a multicentre 2-year experience.

AIMS: The aim of this study is to examine the safety and efficacy of outpatient treatment of worsening heart failure (WHF) with intravenous diuretics. METHODS AND RESULTS: This is a multicentre retrospective observational research study. Patients with all types of heart failure (HF) were included: heart failure with reduced ejection fraction (HFrEF), heart failure with mildly reduced ejection fraction (HFmrEF), and heart failure with preserved ejection fraction (HFpEF). Patients included in this study were 18 years or older, had symptoms of WHF, had weight gain of more than 2 kg, and were not responding to uptitrating of oral diuretic therapy. Patients were treated for one or more days at the outpatient department with administration of intravenous loop diuretics with or without a bolus. In this study, 259 patients were included (mean age of 76 years, mean left ventricular ejection fraction of 41%). Rehospitalization rates for HF were 30.5% and 53.3%, respectively, at 30 days and 1 year. All-cause mortality was 5.8% and 26.3%, respectively, at 30 days and 1 year. Rehospitalization rates for HF and all-cause mortality were highest in patients with HFrEF. In a total of 322 individual outpatient treatments with intravenous diuretics, only one adverse event was registered. CONCLUSIONS: Outpatient treatment with intravenous diuretics of patients with WHF is a safe alternative strategy compared with the same treatment in hospitalized patients. However, only non-randomized data are available and rehospitalization rates for this group with WHF are high. No data are available on the best selection criteria and the cost-effectiveness of outpatient treatment with intravenous diuretics.

Temporal validation of 30-day mortality prediction models for transcatheter aortic valve implantation using statistical process control - An observational study in a national population.

Background: Various mortality prediction models for Transcatheter Aortic Valve Implantation (TAVI) have been developed in the past years. The effect of time on the performance of such models, however, is unclear given the improvements in the procedure and changes in patient selection, potentially jeopardizing the usefulness of the prediction models in clinical practice. We aim to explore how time affects the performance and stability of different types of prediction models of 30-day mortality after TAVI. Methods: We developed both parametric (Logistic Regression) and non-parametric (XGBoost) models to predict 30-day mortality after TAVI using data from the Netherlands Heart Registration. The models were trained with data from 2013 to the beginning of 2016 and pre-control charts from Statistical Process Control were used to analyse how time affects the models' performance on independent data from the mid of 2016 to the end of 2019. The area under the Receiver Operating Characteristics curve (AUC) was used to evaluate the models in terms of discrimination and the Brier Score (BS), which is related to calibration, in terms of accuracy of the predicted probabilities. To understand the extent to which refitting the models contribute to the models' stability, we also allowed the models to be updated over time. Results: We included data from 11,291 consecutive TAVI patients from hospitals in the Netherlands. The parametric model without re-training had a median AUC of 0.64 (IQR 0.54-0.73) and BS of 0.028 (IQR 0.021-0.035). For the non-parametric model, the median AUC was 0.63 (IQR 0.48-0.68) and BS was 0.027 (IQR 0.021-0.036). Over time, the developed parametric model was stable in terms of AUC and unstable in terms of BS. The non-parametric model was considered unstable in both AUC and BS. Repeated model refitting resulted in stable models in terms of AUC and decreased the variability of BS, although BS was still unstable. The refitted parametric model had a median AUC of 0.66 (IQR 0.57-0.73) and BS of 0.027 (IQR 0.020-0.035) while the non-parametric model had a median AUC of 0.66 (IQR 0.57-0.74) and BS of 0.027 (IQR 0.023-0.035). Conclusions: The temporal validation of the TAVI 30-day mortality prediction models showed that the models refitted over time are more stable and accurate when compared to the frozen models. This highlights the importance of repeatedly refitted models over time to improve or at least maintain their performance stability. The non-parametric approach did not show improvement over the parametric approach.

Noninvasive continuous arterial blood pressure monitoring with Nexfin®.

BACKGROUND: If invasive measurement of arterial blood pressure is not warranted, finger cuff technology can provide continuous and noninvasive monitoring. Finger and radial artery pressures differ; Nexfin® (BMEYE, Amsterdam, The Netherlands) measures finger arterial pressure and uses physiologic reconstruction methodologies to obtain values comparable to invasive pressures. METHODS: Intra-arterial pressure (IAP) and noninvasive Nexfin arterial pressure (NAP) were measured in cardiothoracic surgery patients, because invasive pressures are available. NAP-IAP differences were analyzed during 30 min. Tracking was quantified by within-subject precision (SD of individual NAP-IAP differences) and correlation coefficients. The ranges of pressure change were quantified by within-subject variability (SD of individual averages of NAP and IAP). Accuracy and precision were expressed as group average ± SD of the differences and considered acceptable when smaller than 5 ± 8 mmHg, the Association for the Advancement of Medical Instrumentation criteria. RESULTS: NAP and IAP were obtained in 50 (34-83 yr, 40 men) patients. For systolic, diastolic, mean arterial, and pulse pressure, median (25-75 percentiles) correlation coefficients were 0.96 (0.91-0.98), 0.93 (0.87-0.96), 0.96 (0.90-0.97), and 0.94 (0.85-0.98), respectively. Within-subject precisions were 4 ± 2, 3 ± 1, 3 ± 2, and 3 ± 2 mmHg, and within-subject variations 13 ± 6, 6 ± 3, 9 ± 4, and 7 ± 4 mmHg, indicating precision over a wide range of pressures. Group average ± SD of the NAP-IAP differences were -1 ± 7, 3 ± 6, 2 ± 6, and -3 ± 4 mmHg, meeting criteria. Differences were not related to mean arterial pressure or heart rate. CONCLUSION: Arterial blood pressure can be measured noninvasively and continuously using physiologic pressure reconstruction. Changes in pressure can be followed and values are comparable to invasive monitoring.

Prospective ECG triggering reduces prosthetic heart valve-induced artefacts compared with retrospective ECG gating on 256-slice CT.

OBJECTIVES: Multidetector computed tomography (MDCT) has diagnostic value for the evaluation of prosthetic heart valve (PHV) dysfunction but it is hampered by artefacts. We hypothesised that image acquisition using prospective triggering instead of retrospective gating would reduce artefacts related to pulsating PHV. METHODS: In a pulsatile in vitro model, a mono- and bileaflet PHV were imaged using 256 MDCT at 60, 75 and 90 beats per minute (BPM) with either retrospective gating (120 kV, 600 mAs, pitch 0.2, CTDI(vol) 39.8 mGy) or prospective triggering (120 kV, 200 mAs, CTDI(vol) 13.3 mGy). Two thresholds (>175 and <-45HU), derived from the density of surrounding structures, were used for quantification of hyper- and hypodense artefacts. Image noise and artefacts were compared between protocols. RESULTS: Prospective triggering reduced hyperdense artefacts for both valves at every BPM (P = 0.001 all comparisons). Hypodense artefacts were reduced for the monoleaflet valve at 60 (P = 0.009), 75 (P = 0.016) and 90 BPM (P = 0.001), and for the bileaflet valves at 60 (P = 0.001), 90 (P = 0.001) but not at 75 BPM (P = 0.6). Prospective triggering reduced image noise at 60 (P = 0.001) and 75 (P < 0.03) but not at 90 BPM. CONCLUSIONS: Compared with retrospective gating, prospective triggering reduced most artefacts related to pulsating PHV in vitro. KEY POINTS: • Computed tomographic images are often degraded by prosthetic heart valve-induced artefacts • Prospective triggering reduces prosthetic heart valve-induced artefacts in vitro • Artefact reduction at 90 beats per minute occurs without image noise reduction • Prospective triggering may improve CT image quality of moving hyperdense structures.

Imbalance of arginine and asymmetric dimethylarginine is associated with markers of circulatory failure, organ failure and mortality in shock patients.

In shock, organ perfusion is of vital importance because organ oxygenation is at risk. NO, the main endothelial-derived vasodilator, is crucial for organ perfusion and coronary patency. The availability of NO might depend on the balance between a substrate (arginine) and an inhibitor (asymmetric dimethylarginine; ADMA) of NO synthase. Therefore, we investigated the relationship of arginine, ADMA and their ratio with circulatory markers, disease severity, organ failure and mortality in shock patients. In forty-four patients with shock (cardiogenic n 17, septic n 27), we prospectively measured plasma arginine and ADMA at intensive care unit admission, Acute Physiology and Chronic Health Evaluation (APACHE) II-(predicted mortality) and Sequential Organ Failure Assessment (SOFA) score, and circulatory markers to investigate their relationship. Arginine concentration was decreased (34·6 (SD 17·9) µmol/l) while ADMA concentration was within the normal range (0·46 (SD 0·18) µmol/l), resulting in a decrease in the arginine:ADMA ratio. The ratio correlated with several circulatory markers (cardiac index, disseminated intravascular coagulation, bicarbonate, lactate and pH), APACHE II and SOFA score, creatine kinase and glucose. The arginine:ADMA ratio showed an association (OR 0·976, 95 % CI 0·963, 0·997, P = 0·025) and a diagnostic accuracy (area under the curve 0·721, 95 % CI 0·560, 0·882, P = 0·016) for hospital mortality, whereas the arginine or ADMA concentration alone or APACHE II-predicted mortality failed to do so. In conclusion, in shock patients, the imbalance of arginine and ADMA is related to circulatory failure, organ failure and disease severity, and predicts mortality. We propose a pathophysiological mechanism in shock: the imbalance of arginine and ADMA contributes to endothelial and cardiac dysfunction resulting in poor organ perfusion and organ failure, thereby increasing the risk of death.

Application of local gentamicin in the treatment of deep sternal wound infection: a randomized controlled trial.

OBJECTIVES: In patients with deep sternal wound infection (DSWI), primary closure of the sternal bone over high negative pressure Redon drains has shown to be a safe and feasible treatment method. Addition of local gentamicin could accelerate healing and improve clinical outcomes. METHODS: We conducted a randomized controlled trial to evaluate the effectiveness of local gentamicin in the treatment of DSWI. In the treatment group, collagenous carriers containing gentamicin were left between the sternal halves during sternal refixation. In the control group, no local antibiotics were used. Primary outcome was hospital stay. Secondary outcomes were mortality, reoperation, wound sterilization time, time till removal of all drains and duration of intravenous antibiotic treatment. RESULTS: Forty-one patients were included in the trial of which 20 were allocated to the treatment group. Baseline characteristics were similar in both groups. Drains could be removed after a median of 8.5 days in the treatment group and 14.5 days in the control group (P-value: 0.343). Intravenous antibiotics were administered for a median of 23.5 days in the treatment group and 38.5 days in the control group (P-value: 0.343). The median hospital stay was 27 days in the treatment group and 28 days in the control group (P-value: 0.873). Mortality rate was 10% in the treatment group and 9.5% in the control group (P-value: 0,959). No side effects were observed. CONCLUSIONS: This randomized controlled trial showed that addition of local gentamicin in the treatment of DSWI did not result in shorter length of stay. CLINICAL TRIAL REGISTRATION NUMBER: 2014-001170-33.

Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model.

OBJECTIVES: Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. METHODS: A Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stationary and pulsatile conditions. Artifacts and radiopaque component volumes were quantified with thresholds based on surrounding structures and valvular components. RESULTS: Hypodense artifacts volumes (mm³) were 1,029 ± 147, 535 ± 53, 371 ± 16, and 366 ± 18 for the SJM, MH, CM and ON-X valves (p < 0.001 except for the latter two valves p = 0.43). Hyperdense artifact volumes were 3,546 ± 141, 2,387 ± 103, 2,003 ± 102, and 3,033 ± 31 for the SJM, MH, CM and ON-X valve, respectively (all differences p < 0.001). Leaflet motion affected hypodense (F = 41.5, p < 0.001) and hyperdense artifacts (F = 53.7, p < 0.001). Closed and moving leaflets were associated with the least and the most artifacts respectively (p < 0.001, both artifact types). CONCLUSION: Both valve design and leaflet motion affect PHV-induced artifacts. Best imaging results may be expected for the CM valve during phases in which the leaflets are closed.

Prosthetic heart valve assessment with multidetector-row CT: imaging characteristics of 91 valves in 83 patients.

OBJECTIVES: Multidetector CT (MDCT) has shown potential for prosthetic heart valve (PHV) assessment. We assessed the image quality of different PHV types to determine which valves are suitable for MDCT evaluation. METHODS: All ECG-gated CTs performed in our institutions since 2003 were reviewed for the presence of PHVs. After reconstruction in 3 specific PHV planes, image quality of the supravalvular, perivalvular, subvalvular and valvular regions was scored on a four-point scale (1 = non-diagnostic, 2 = moderate, 3 = good and 4 = excellent) by two independent observers. RESULTS: Eighty-four CT examinations (66 cardiac, 18 limited-dose aortic protocols) of 83 patients with a total of 91 PHVs in the aortic (n = 71), mitral (n = 17), pulmonary (n = 1) and tricuspid (n = 2) position were included. CT was performed on a 16-slice (n = 4), 64-slice (n = 28) or 256-slice (n = 52) MDCT system. Median image quality scores for the supra-, peri- and subvalvular regions and valvular detail were (3.5, 3.3, 3.5 and 3.5, respectively) for bileaflet PHV; (3.0, 3.0, 3.5 and 3.0, respectively) for Medtronic Hall PHV; (1.0, 1.0, 1.0 and 1.0, respectively) for Björk-Shiley and Sorin monoleaflet PHV and (3.5, 3.5, 4.0 and 2.0 respectively) for biological PHV. CONCLUSION: Currently implanted PHVs have good image quality on MDCT and are suitable for MDCT evaluation.

Manual hyperinflation partly prevents reductions of functional residual capacity in cardiac surgical patients--a randomized controlled trial.

INTRODUCTION: Cardiac surgery is associated with post-operative reductions of functional residual capacity (FRC). Manual hyperinflation (MH) aims to prevent airway plugging, and as such could prevent the reduction of FRC after surgery. The main purpose of this study was to determine the effect of MH on post-operative FRC of cardiac surgical patients. METHODS: This was a randomized controlled trial of patients after elective coronary artery bypass graft and/or valve surgery admitted to the intensive care unit (ICU) of a university hospital. Patients were randomly assigned to a "routine MH group" (MH was performed within 30 minutes after admission to the ICU and every 6 hours thereafter, and before tracheal extubation), or a "control group" (MH was performed only if perceptible (audible) sputum was present in the larger airways causing problems with mechanical ventilation, or if oxygen saturation (SpO2) dropped below 92%). The primary endpoint was the reduction of FRC from the day before cardiac surgery to one, three, and five days after tracheal extubation. Secondary endpoints were SpO2 (at similar time points) and chest radiograph abnormalities, including atelectasis (at three days after tracheal extubation). RESULTS: A total of 100 patients were enrolled. Patients in the routine MH group showed a decrease of FRC on the first post-operative day to 71% of the pre-operative value, versus 57% in the control group (P = 0.002). Differences in FRC became less prominent over time; differences between the two study groups were no longer statistically significant at Day 5. There were no differences in SpO2 between the study groups. Chest radiographs showed more abnormalities (merely atelectasis) in the control group compared to patients in the routine MH group (P = 0.002). CONCLUSIONS: MH partly prevents the reduction of FRC in the first post-operative days after cardiac surgery. TRIAL REGISTRATION: Netherlands Trial Register (NTR): NTR1384. http://www.trialregister.nl.

Multidetector-row computed tomography imaging characteristics of mechanical prosthetic valves.

BACKGROUND AND AIM OF THE STUDY: Electrocardiogram-gated multidetector-row computed tomography (MDCT) imaging may aid in the evaluation of prosthetic valve dysfunction. A pulsatile in vitro model was developed to study the MDCT imaging characteristics of mechanical heart valves (MHVs). METHODS: Björk-Shiley (BS), St. Jude Medical (SJM), Medtronic-Hall (MH), CarboMedics (CM) and ON-X valves were inserted into an in vitro pulsatile model and scanned using a 64-detector row scanner. The image quality regarding visualization of the leaflets, prosthetic detail and periprosthetic detail, as well as the presence of image artifacts, was scored on a four-point scale. RESULTS: The image quality for the BS valve was scored poor to moderate for all criteria, and was inferior to that seen with the other valves. Leaflet visualization was excellent for all the other valves. The prosthetic detail was good for MH and SJM valves, and excellent for the CM and ON-X valves. Periprosthetic detail was good for MH, SJM and CM valves, and excellent for ON-X valves. Artifacts were moderate for MH and SJM valves, minor for CM, and minimal for ON-X. All differences were shown to be statistically significant (p < 0.001). CONCLUSION: The pulsatile in vitro model is an effective tool to detect differences in the MDCT imaging characteristics of MHVs. The image quality is determined by the prosthesis components and, to a lesser degree, by prosthesis design. Modern carbon-titanium MHVs yield good to excellent image quality on MDCT.