Shear Forces Induced Platelet Clearance Is a New Mechanism of Thrombocytopenia.

BACKGROUND: Thrombocytopenia has been consistently described in patients with extracorporeal membrane oxygenation (ECMO) and associated with poor outcome. However, the prevalence and underlying mechanisms remain largely unknown, and a device-related role of ECMO in thrombocytopenia has been hypothesized. This study aims to investigate the mechanisms underlying thrombocytopenia in ECMO patients. METHODS: In a prospective cohort of 107 ECMO patients, we investigated platelet count, functions, and glycoprotein shedding. In an ex vivo mock circulatory ECMO loop, we assessed platelet responses and VWF (von Willebrand factor)-GP Ibα (glycoprotein Ibα) interactions at low- and high-flow rates, in the presence or absence of red blood cells. The clearance of human platelets subjected or not to ex vivo perfusion was studied using an in vivo transfusion model in NOD/SCID (nonobese diabetic/severe combined Immunodeficient) mice. RESULTS: In ECMO patients, we observed a time-dependent decrease in platelet count starting 1 hour after device onset, with a mean drop of 7%, 35%, and 41% at 1, 24, and 48 hours post-ECMO initiation (P=0.00013, P<0.0001, and P<0.0001, respectively), regardless of the type of ECMO. This drop in platelet count was associated with a decrease in platelet GP Ibα expression (before: 47.8±9.1 versus 24 hours post-ECMO: 42.3±8.9 mean fluorescence intensity; P=0.002) and an increase in soluble GP Ibα plasma levels (before: 5.6±3.3 versus 24 hours post-ECMO: 10.8±4.1 µg/mL; P<0.0001). GP Ibα shedding was also observed ex vivo and was unaffected by (1) red blood cells, (2) the coagulation potential, (3) an antibody blocking VWF-GP Ibα interaction, (4) an antibody limiting VWF degradation, and (5) supraphysiological VWF plasma concentrations. In contrast, GP Ibα shedding was dependent on rheological conditions, with a 2.8-fold increase at high- versus low-flow rates. Platelets perfused at high-flow rates before being transfused to immunodeficient mice were eliminated faster in vivo with an accelerated clearance of GP Ibα-negative versus GP Ibα-positive platelets. CONCLUSIONS: ECMO-associated shear forces induce GP Ibα shedding and thrombocytopenia due to faster clearance of GP Ibα-negative platelets. Inhibiting GP Ibα shedding could represent an approach to reduce thrombocytopenia during ECMO.

Right Ventriculoarterial Coupling Surrogates and Long-Term Survival in LVAD Recipients: Results of the ASSIST-ICD Multicentric Registry.

BACKGROUND: Prediction of outcomes remains an unmet need in candidates for LVADs. The development of right-heart failure portends an excess in mortality rates, but imaging parameters of right ventricular systolic function have failed to demonstrate a prognostic role. By integrating pulmonary pressure, right ventriculoarterial coupling could fill this gap. METHODS: The ASSIST-ICD registry was used to test right ventriculoarterial coupling as a surrogate parameter at implantation for the prediction of all-cause mortality. RESULTS: The ratio of the tricuspid annular-plane systolic excursion over the estimated systolic pulmonary pressure (TAPSE/sPAP) was not associated with long-term survival in univariate analysis (P = 0.89), nor was the pulmonary artery pulsatility index (PAPi) (P = 0.13). Conversely, the ratio of the right atrial pressure over the pulmonary capillary wedge pressure (RAP/PCWP) was associated with all-cause mortality (P < 0.01). After taking tricuspid regurgitation severity, LVAD indication, LVAD model, age, blood urea nitrogen levels, and pulmonary vascular resistance into account, RAP/PCWP remained associated with survival (HR 1.35 [1.10 - 1.65]; P < 0.01). CONCLUSION: Among pre-implant RVAC surrogates, only RAP/PCWP was associated with long-term all-cause mortality in LVAD recipients. This association was independent of established risk factors.

Healthcare-associated infections in patients with severe COVID-19 supported with extracorporeal membrane oxygenation: a nationwide cohort study.

BACKGROUND: Both critically ill patients with coronavirus disease 2019 (COVID-19) and patients receiving extracorporeal membrane oxygenation (ECMO) support exhibit a high incidence of healthcare-associated infections (HAI). However, data on incidence, microbiology, resistance patterns, and the impact of HAI on outcomes in patients receiving ECMO for severe COVID-19 remain limited. We aimed to report HAI incidence and microbiology in patients receiving ECMO for severe COVID-19 and to evaluate the impact of ECMO-associated infections (ECMO-AI) on in-hospital mortality. METHODS: For this study, we analyzed data from 701 patients included in the ECMOSARS registry which included COVID-19 patients supported by ECMO in France. RESULTS: Among 602 analyzed patients for whom HAI and hospital mortality data were available, 214 (36%) had ECMO-AI, resulting in an incidence rate of 27 ECMO-AI per 1000 ECMO days at risk. Of these, 154 patients had bloodstream infection (BSI) and 117 patients had ventilator-associated pneumonia (VAP). The responsible microorganisms were Enterobacteriaceae (34% for BSI and 48% for VAP), Enterococcus species (25% and 6%, respectively) and non-fermenting Gram-negative bacilli (13% and 20%, respectively). Fungal infections were also observed (10% for BSI and 3% for VAP), as were multidrug-resistant organisms (21% and 15%, respectively). Using a Cox multistate model, ECMO-AI were not found associated with hospital death (HR = 1.00 95% CI [0.79-1.26], p = 0.986). CONCLUSIONS: In a nationwide cohort of COVID-19 patients receiving ECMO support, we observed a high incidence of ECMO-AI. ECMO-AI were not found associated with hospital death. Trial registration number NCT04397588 (May 21, 2020).

Definitions of major bleeding for predicting mortality in critically ill adult patients who survived 24 hours while supported with peripheral veno-arterial extracorporeal membrane oxygenation for cardiogenic shock: a comparative historical cohort study.

PURPOSE: The severity of bleeding events is heterogeneously defined during peripheral veno-arterial extracorporeal membrane oxygenation (pVA-ECMO). We studied three bleeding definitions in pVA-ECMO: the Extracorporeal Life Support Organization (ELSO)-serious bleeding, the Bleeding Academic Research Consortium (BARC), and the universal definition of postoperative bleeding (UPDB) classifications. METHODS: We included consecutive adult patients supported by pVA-ECMO for refractory cardiogenic shock admitted to Lille academic hospitals between January 2013 and December 2019. We assessed the association of bleeding definitions with the primary endpoint of 28-day all-cause mortality with the use of multivariate models accounting for time-dependent and competing variables. We compared models' performances using the Harrell's C-Index and the Akaike information criteria. RESULTS: Twenty-eight-day mortality occurred in 128/308 (42%) 308 patients. The ELSO-serious bleeding (hazard ratio [HR], 1.67; 95% confidence interval [CI], 1.09 to 2.56) and BARC ≥ type 2 (HR, 1.55; 95% CI, 1.01 to 2.37) were associated with 28-day mortality (Harrell's C-index, 0.69; 95% CI, 0.63 to 0.74 for both). Predictors of ELSO-serious bleeding were postcardiotomy, body mass index, baseline platelets count, fibrinogen, and hemoglobin levels. CONCLUSION: Extracorporeal Life Support Organization-serious bleeding and BARC ≥ type 2 are relevant definitions of major bleeding regarding their association with mortality in critically ill patients who survived the first 24 hr while supported with pVA-ECMO for cardiogenic shock. STUDY REGISTRATION: CERAR (IRB 00010254-2022-050, Paris, France); first submitted on 18 April 2022.

RéSUMé: OBJECTIF: La gravité des événements hémorragiques est définie de manière hétérogène pendant une oxygénation par membrane extracorporelle veino-artérielle périphérique (ECMO-VA périphérique). Nous avons étudié trois définitions du saignement sous ECMO-VA périphérique : les classifications des saignements graves selon l'Extracorporeal Life Support Organization (ELSO), celles du Bleeding Academic Research Consortium (BARC) et la définition universelle du saignement postopératoire (UPDB). MéTHODE: Nous avons inclus des patient·es adultes pris·es en charge de manière consécutive par ECMO-VA périphérique à la suite d'un choc cardiogénique réfractaire et admis·es dans les centres hospitaliers universitaires de Lille entre janvier 2013 et décembre 2019. Nous avons évalué l'association des définitions du saignement avec le critère d'évaluation principal de mortalité toutes causes confondues à 28 jours à l'aide de modèles multivariés tenant compte des variables dépendantes du temps et concurrentes. Nous avons comparé les performances des modèles à l'aide de l'indice C de Harrell et du critère d'information d'Akaike. RéSULTATS: La mortalité à 28 jours est survenue chez 128/308 (42 %) patient·es. Le saignement grave selon l'ELSO (rapport de risque [RR], 1,67; intervalle de confiance [IC] à 95 %, 1,09 à 2,56) et une classification BARC ≥ type 2 (RR, 1,55; IC 95 %, 1,01 à 2,37) étaient associés à une mortalité à 28 jours (indice C de Harrell, 0,69; IC 95 %, 0,63 à 0,74 pour les deux). Les prédicteurs d'hémorragie grave selon l'ELSO étaient la postcardiotomie, l'indice de masse corporelle, la numération plaquettaire initiale, le taux de fibrinogène et les taux d'hémoglobine. CONCLUSION: Les définitions du saignement grave de l'Extracorporeal Life Support Organization et une classification BARC ≥ type 2 sont des définitions pertinentes des saignements majeurs en ce qui touche à leur association avec la mortalité chez les personnes gravement malades qui ont survécu aux premières 24 heures alors qu'elles étaient prises en charge par ECMO-VA périphérique à la suite d'un choc cardiogénique. ENREGISTREMENT DE L'éTUDE: CERAR (IRB 00010254-2022-050, Paris, France); soumis pour la première fois le 18 avril 2022.

Incidence, source, and prognostic impact of major bleeding across the spectrum of aortic stenosis.

BACKGROUND: Severe aortic stenosis (AS) has been associated with bleeding. However, there is a lack of prospective assessment of bleeding events and their clinical significance in a large population of outpatients with variable degree of AS severity. OBJECTIVES: To assess the incidence, source, determinants, and prognostic impact of major bleeding in patients with variable degree of AS severity. METHODS: Between May 2016 and December 2017, consecutive outpatients were included. Major bleeding was defined as type ≥3 bleed using the Bleeding Academic Research Consortium definition. Cumulative incidence was calculated with death as the competing event. Data was censored at time of aortic valve replacement. RESULTS: Among 2,830 patients, 46 major bleeding events occurred (0.7%/year) during a median follow-up of 2.1 years (interquartile range: 1.4-2.7). Most frequent sites of bleeding were gastrointestinal (50%) and intracranial (30.4%). Major bleeding was significantly associated with all-cause mortality (hazard ratio: 5.93 (95% confidence interval 3.64-9.65); P < .001). AS severity was associated with major bleedings (P = .041). By multivariable analysis, severe AS was an independent determinant of major bleeding (hazard ratio vs mild AS: 3.59 [95% confidence interval 1.56-8.29]; P = .003). The increased risk of bleeding associated with severe AS was significantly exacerbated in patients using oral anticoagulation. CONCLUSION: In AS patients, major bleeding is rare but a strong independent predictor of death. AS severity is a determinant of bleeding events. Severe AS and oral anticoagulation should be identified as an association at very high risk of major bleeding.

Impact of Prone Position in COVID-19 Patients on Extracorporeal Membrane Oxygenation.

OBJECTIVES: Prone positioning and venovenous extracorporeal membrane oxygenation (ECMO) are both useful interventions in acute respiratory distress syndrome (ARDS). Combining the two therapies is feasible and safe, but the effectiveness is not known. Our objective was to evaluate the potential survival benefit of prone positioning in venovenous ECMO patients cannulated for COVID-19-related ARDS. DESIGN: Retrospective analysis of a multicenter cohort. PATIENTS: Patients on venovenous ECMO who tested positive for severe acute respiratory syndrome coronavirus 2 by reverse transcriptase polymerase chain reaction or with a diagnosis on chest CT were eligible. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All patients on venovenous ECMO for respiratory failure in whom prone position status while on ECMO and in-hospital mortality were known were included. Of 647 patients in 41 centers, 517 were included. Median age was 55 (47-61), 78% were male and 95% were proned before cannulation. After cannulation, 364 patients (70%) were proned and 153 (30%) remained in the supine position for the whole ECMO run. There were 194 (53%) and 92 (60%) deaths in the prone and the supine groups, respectively. Prone position on ECMO was independently associated with lower in-hospital mortality (odds ratio = 0.49 [0.29-0.84]; p = 0.010). In 153 propensity score-matched pairs, mortality rate was 49.7% in the prone position group versus 60.1% in the supine position group (p = 0.085). Considering only patients alive at decannulation, propensity-matched proned patients had a significantly lower mortality rate (22.4% vs 37.8%; p = 0.029) than nonproned patients. CONCLUSIONS: Prone position may be beneficial in patients supported by venovenous ECMO for COVID-19-related ARDS but more data are needed to draw definitive conclusions.

Outcome of Temporary Circulatory Support As a Bridge-to-Left Ventricular Assist Device Strategy in Cardiogenic Shock Patients.

OBJECTIVES: Temporary circulatory support (TCS) as a bridge-to-left ventricular assist device (BTL) in cardiogenic shock patients has been increasing, but limited data exists on this BTL strategy. We aimed at analyzing the outcome of BTL patients in a population of cardiogenic shock patients compared with those without TCS at the time of the left ventricular assist device (LVAD) surgery and identify predictors of postoperative mortality in this specific population. DESIGN: A multicenter retrospective observational study conducted in 19 centers from 2006 to 2016. SETTING: Nineteen French centers. PATIENTS: A total of 329 cardiogenic shock patients at the time of LVAD implantation were analyzed. Patients were divided in three groups: those under TCS at the time of LVAD implantation (n = 173), those with TCS removal before LVAD surgery (n = 24), and those who did not undergo a bridging strategy (n = 152). Primary endpoint was 30-day mortality. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the BTL group, 68 (39.3%), 18 (10.4%), and 15 (8.7%) patients were under venoarterial extracorporeal membrane oxygenation, Impella, and IABP support alone, and 72 patients (20.6%) were under multiple TCS support. BTL patients presented similar 30 days survival compared with the TCS removal and non-BTL groups. However, BTL group had a significantly longer ICU duration stay, with two-fold duration of mechanical ventilation time, but the three groups experienced similar postoperative complications. Multivariate analysis identified three independent predictors of mortality in the BTL group: combined surgery with LVAD, body mass index (BMI), and heart failure (HF) duration. BTL strategy was not an independent predictor of mortality in cardiogenic shock patients who underwent LVAD. CONCLUSIONS: BTL strategy is not associated with a lower survival among cardiogenic shock patients with LVAD implantation. Predictors of mortality are combined surgery with LVAD, higher BMI, and HF duration.

Extracorporeal Membrane Oxygenation for Respiratory Failure Related to COVID-19: A Nationwide Cohort Study.

BACKGROUND: Despite expanding use, knowledge on extracorporeal membrane oxygenation support during the COVID-19 pandemic remains limited. The objective was to report characteristics, management, and outcomes of patients receiving extracorporeal membrane oxygenation with a diagnosis of COVID-19 in France and to identify pre-extracorporeal membrane oxygenation factors associated with in-hospital mortality. A hypothesis of similar mortality rates and risk factors for COVID-19 and non-COVID-19 patients on venovenous extracorporeal membrane oxygenation was made. METHODS: The Extracorporeal Membrane Oxygenation for Respiratory Failure and/or Heart failure related to Severe Acute Respiratory Syndrome-Coronavirus 2 (ECMOSARS) registry included COVID-19 patients supported by extracorporeal membrane oxygenation in France. This study analyzed patients included in this registry up to October 25, 2020, and supported by venovenous extracorporeal membrane oxygenation for respiratory failure with a minimum follow-up of 28 days after cannulation. The primary outcome was in-hospital mortality. Risk factors for in-hospital mortality were analyzed. RESULTS: Among 494 extracorporeal membrane oxygenation patients included in the registry, 429 were initially supported by venovenous extracorporeal membrane oxygenation and followed for at least 28 days. The median (interquartile range) age was 54 yr (46 to 60 yr), and 338 of 429 (79%) were men. Management before extracorporeal membrane oxygenation cannulation included prone positioning for 411 of 429 (96%), neuromuscular blockage for 419 of 427 (98%), and NO for 161 of 401 (40%). A total of 192 of 429 (45%) patients were cannulated by a mobile extracorporeal membrane oxygenation unit. In-hospital mortality was 219 of 429 (51%), with a median follow-up of 49 days (33 to 70 days). Among pre-extracorporeal membrane oxygenation modifiable exposure variables, neuromuscular blockage use (hazard ratio, 0.286; 95% CI, 0.101 to 0.81) and duration of ventilation (more than 7 days compared to less than 2 days; hazard ratio, 1.74; 95% CI, 1.07 to 2.83) were independently associated with in-hospital mortality. Both age (per 10-yr increase; hazard ratio, 1.27; 95% CI, 1.07 to 1.50) and total bilirubin at cannulation (6.0 mg/dl or more compared to less than 1.2 mg/dl; hazard ratio, 2.65; 95% CI, 1.09 to 6.5) were confounders significantly associated with in-hospital mortality. CONCLUSIONS: In-hospital mortality was higher than recently reported, but nearly half of the patients survived. A high proportion of patients were cannulated by a mobile extracorporeal membrane oxygenation unit. Several factors associated with mortality were identified. Venovenous extracorporeal membrane oxygenation support should be considered early within the first week of mechanical ventilation initiation.

Human Aortic Valve Interstitial Cells Display Proangiogenic Properties During Calcific Aortic Valve Disease.

OBJECTIVE: The study's aim was to analyze the capacity of human valve interstitial cells (VICs) to participate in aortic valve angiogenesis. Approach and Results: VICs were isolated from human aortic valves obtained after surgery for calcific aortic valve disease and from normal aortic valves unsuitable for grafting (control VICs). We examined VIC in vitro and in vivo potential to differentiate in endothelial and perivascular lineages. VIC paracrine effect was also examined on human endothelial colony-forming cells. A pathological VIC (VICp) mesenchymal-like phenotype was confirmed by CD90+/CD73+/CD44+ expression and multipotent-like differentiation ability. When VICp were cocultured with endothelial colony-forming cells, they formed microvessels by differentiating into perivascular cells both in vivo and in vitro. VICp and control VIC conditioned media were compared using serial ELISA regarding quantification of endothelial and angiogenic factors. Higher expression of VEGF (vascular endothelial growth factor)-A was observed at the protein level in VICp-conditioned media and confirmed at the mRNA level in VICp compared with control VIC. Conditioned media from VICp induced in vitro a significant increase in endothelial colony-forming cell proliferation, migration, and sprouting compared with conditioned media from control VIC. These effects were inhibited by blocking VEGF-A with blocking antibody or siRNA approach, confirming VICp involvement in angiogenesis by a VEGF-A dependent mechanism. CONCLUSIONS: We provide here the first proof of an angiogenic potential of human VICs isolated from patients with calcific aortic valve disease. These results point to a novel function of VICp in valve vascularization during calcific aortic valve disease, with a perivascular differentiation ability and a VEGF-A paracrine effect. Targeting perivascular differentiation and VEGF-A to slow calcific aortic valve disease progression warrants further investigation.

Early hyperoxia and 28-day mortality in patients on venoarterial ECMO support for refractory cardiogenic shock: a bicenter retrospective propensity score-weighted analysis.

BACKGROUND: The mortality rate for a patient with a refractory cardiogenic shock on venoarterial (VA) extracorporeal membrane oxygenation (ECMO) remains high, and hyperoxia might worsen this prognosis. The objective of the present study was to evaluate the association between hyperoxia and 28-day mortality in this setting. METHODS: We conducted a retrospective bicenter study in two French academic centers. The study population comprised adult patients admitted for refractory cardiogenic shock. The following arterial partial pressure of oxygen (PaO2) variables were recorded for 48 h following admission: the absolute peak PaO2 (the single highest value measured during the 48 h), the mean daily peak PaO2 (the mean of each day's peak values), the overall mean PaO2 (the mean of all values over 48 h), and the severity of hyperoxia (mild: PaO2 < 200 mmHg, moderate: PaO2 = 200-299 mmHg, severe: PaO2 ≥ 300 mmHg). The main outcome was the 28-day all-cause mortality. Inverse probability weighting (IPW) derived from propensity scores was used to reduce imbalances in baseline characteristics. RESULTS: From January 2013 to January 2020, 430 patients were included and assessed. The 28-day mortality rate was 43%. The mean daily peak, absolute peak, and overall mean PaO2 values were significantly higher in non-survivors than in survivors. In a multivariate logistic regression analysis, the mean daily peak PaO2, absolute peak PaO2, and overall mean PaO2 were independent predictors of 28-day mortality (adjusted odds ratio [95% confidence interval per 10 mmHg increment: 2.65 [1.79-6.07], 2.36 [1.67-4.82], and 2.85 [1.12-7.37], respectively). After IPW, high level of oxygen remained significantly associated with 28-day mortality (OR = 1.41 [1.01-2.08]; P = 0.041). CONCLUSIONS: High oxygen levels were associated with 28-day mortality in patients on VA-ECMO support for refractory cardiogenic shock. Our results confirm the need for large randomized controlled trials on this topic.

Preliminary results of a simplified aortic valve-sparing technique: A feasibility study.

BACKGROUND AND AIM OF THE STUDY: To evaluate whether the simplified valve-sparing technique (SVST) implies clinical outcomes comparable or not with those of established David technique in the surgery of aortic root. METHODS: We collected the records of patients who had undergone aortic root surgery with the SVST or standard David technique (SDT) at our institution between January 2009 and December 2018. The primary endpoints were the incidence of all-cause death, reoperation for any reason, and postoperative complications. The secondary endpoint was the midterm incidence of reoperation for aortic valve regurgitation. RESULTS: A total of 169 patients who underwent aortic root surgery were analyzed. SDT and SVST were performed in 48 (28.4%) and in 121 (71.6%) patients, respectively. Thirty-day mortality occurred in 0% and 0.8% of patients in the SDT and SVST groups, respectively. The rate of postoperative new permanent pacemaker implantation was 6.3% (three patients) and 0.8% (one patient) in SDT and SVST cohort, respectively (p = .07). The incidence of postoperative thromboembolic stroke was 6.3% and 2.5% in SDT and SVST groups, respectively (p = .23). The median follow-up time was 29 (23-47) months. During the FU period, no differences were found between two cohorts in terms of all-cause mortality (p = .99), the incidence of reoperation (p = .19), and incidence of aortic valve regurgitation requiring reoperation (p = .58). CONCLUSIONS: The SVST appears to be safe and feasible showing early clinical results comparable to the SDT. Nevertheless, further studies with larger series and long-term follow-ups are required to demonstrate its safety and efficacy.

Anti-Xa activity and hemorrhagic events under extracorporeal membrane oxygenation (ECMO): a multicenter cohort study.

BACKGROUND: Hemorrhagic events remain a major concern in patients under extracorporeal membrane oxygenation (ECMO) support. We tested the association between anticoagulation levels and hemorrhagic events under ECMO using anti-Xa activity monitoring. METHODS: We performed a retrospective multicenter cohort study in three ECMO centers. All adult patients treated with veno-venous (VV)- or veno-arterial (VA)-ECMO in 6 intensive care units between September 2017 and August 2019 were included. Anti-Xa activities were collected until a hemorrhagic event in the bleeding group and for the duration of ECMO in the non-bleeding group. All dosages were averaged to obtain means of anti-Xa activity for each patient, and patients were compared according to the occurrence or not of bleeding. RESULTS: Among 367 patients assessed for eligibility, 121 were included. Thirty-five (29%) presented a hemorrhagic complication. In univariate analysis, anti-Xa activities were significantly higher in the bleeding group than in the non-bleeding group, both for the mean anti-Xa activity (0.38 [0.29-0.67] vs 0.33 [0.22-0.42] IU/mL; p = 0.01) and the maximal anti-Xa activity (0.83 [0.47-1.46] vs 0.66 [0.36-0.91] IU/mL; p = 0.05). In the Cox proportional hazard model, mean anti-Xa activity was associated with bleeding (p = 0.0001). By Kaplan-Meier analysis with the cutoff value at 0.46 IU/mL obtained by ROC curve analysis, the probability of survival under ECMO without bleeding was significantly lower when mean anti-Xa was > 0.46 IU/mL (p = 0.0006). CONCLUSION: In critically ill patients under ECMO, mean anti-Xa activity was an independent risk factor for hemorrhagic complications. Anticoagulation targets could be revised downward in both VV- and VA-ECMO.

Implantable cardiac defibrillator leads dysfunction after LVAD implantation.

BACKGROUND: Implantable cardioverter-defibrillator (ICD) lead dysfunction has been reported after left ventricular assist device (LVAD) implantation in limited single-center studies. We aimed at describing and characterizing the incidence of ICD lead parameters dysfunction after LVAD implantation. METHODS: Among the 652 patients enrolled in the ASSIST-ICD study, only patients with an ICD prior to LVAD were included (n = 401). ICD lead parameters dysfunction following LVAD implantation is defined as follows: (a) >50% decrease in sensing threshold, (b) pacing lead impedance increase/decrease by >100Ω, and (c) >50% increase in pacing threshold. RESULTS: One hundred twenty-two patients with an ICD prior to LVAD had available ICD interrogation reports prior and after LVAD. A total of 67 (55%) patients exhibited at least one significant lead dysfunction: 17 (15%) exhibited >50% decrease in right ventricular (RV) sensing, 51 (42%) had >100 Ω increase/decrease in RV pacing impedance, and 24 (20%) experienced >50% increase in RV pacing threshold. A total of 52 patients experienced ventricular arrhythmia during follow-up and all were successfully detected and treated by the device. All lead dysfunction could be managed conservatively. CONCLUSION: More than 50% of LVAD-recipients may experience >1 significant change in lead parameters but none had severe clinical consequences.

Aortic morphology post type A acute aortic syndrome: Prognosis significance and association with 24-hour blood pressure-monitoring parameters.

BACKGROUND: After an emergent surgery for type A acute aortic syndrome, medical management is based on optimal blood pressure (BP) control. We assessed the prognostic significance of BP monitoring and its relationship with aortic morphology following type A acute aortic syndrome. METHODS: The data of 120 patients who underwent BP monitoring after a type A acute aortic syndrome from January 2005 to June 2016 were retrospectively collected. The first CT angiogram performed after surgery was used for the morphological analysis. RESULTS: The population included 79 males, with an overall mean age of 60 ± 12 years. Seven patients (5.8%) died during a median follow-up of 5.5 years. The median delay between BP monitoring and discharge was 3 (1-5) months. The mean 24-hour BP of the cohort was 127/73 mm Hg ± 10/17. During follow-up, different parameters of BP monitoring were not associated with the risk of aortic events. However, the diameter of the false lumen of the descending thoracic aorta was the best predictor associated with the risk of new aortic events during follow-up, particularly for the threshold of 28 mm or more (P < .001; Hazard ratio 4.7[2.7-8.2]). The diameter of the false lumen was associated with night-time systolic BP (P = .025; r = .2), 24-hour pulse pressure (P = .002; r = .28), and night-time pulse pressure (P = .008; r = .24). CONCLUSION: The risk of new aortic events following type A acute aortic syndrome is associated with the size of the residual false lumen, but not directly with BP parameters. Night-time BP parameters are associated with the size of the residual false lumen.

Von Willebrand Factor Multimers during Transcatheter Aortic-Valve Replacement.

BACKGROUND: Postprocedural aortic regurgitation occurs in 10 to 20% of patients undergoing transcatheter aortic-valve replacement (TAVR) for aortic stenosis. We hypothesized that assessment of defects in high-molecular-weight (HMW) multimers of von Willebrand factor or point-of-care assessment of hemostasis could be used to monitor aortic regurgitation during TAVR. METHODS: We enrolled 183 patients undergoing TAVR. Patients with aortic regurgitation after the initial implantation, as identified by means of transesophageal echocardiography, underwent additional balloon dilation to correct aortic regurgitation. HMW multimers and the closure time with adenosine diphosphate (CT-ADP), a point-of-care measure of hemostasis, were assessed at baseline and 5 minutes after each step of the procedure. Mortality was evaluated at 1 year. A second cohort (201 patients) was studied to validate the use of CT-ADP in order to identify patients with aortic regurgitation. RESULTS: After the initial implantation, HMW multimers normalized in patients without aortic regurgitation (137 patients). Among the 46 patients with aortic regurgitation, normalization occurred in 20 patients in whom additional balloon dilation was successful but did not occur in the 26 patients with persistent aortic regurgitation. A similar sequence of changes was observed with CT-ADP. A CT-ADP value of more than 180 seconds had sensitivity, specificity, and negative predictive value of 92.3%, 92.4%, and 98.6%, respectively, for aortic regurgitation, with similar results in the validation cohort. Multivariable analyses showed that the values for HMW multimers and CT-ADP at the end of TAVR were each associated with mortality at 1 year. CONCLUSIONS: The presence of HMW-multimer defects and a high value for a point-of-care hemostatic test, the CT-ADP, were each predictive of the presence of aortic regurgitation after TAVR and were associated with higher mortality 1 year after the procedure. (Funded by Lille 2 University and others; ClinicalTrials.gov number, NCT02628509.).

Risk factors and prognostic impact of left ventricular assist device-associated infections.

BACKGROUND: Left ventricular assist device (LVAD)-associated infections may be life-threatening and impact patients' outcome. We aimed to identify the characteristics, risk factors, and prognosis of LVAD-associated infections. METHODS: Patients included in the ASSIST-ICD study (19 centers) were enrolled. The main outcome was the occurrence of LVAD-associated infection (driveline infection, pocket infection, or pump/cannula infection) during follow-up. RESULTS: Of the 652 patients enrolled, 201 (30.1%) presented a total of 248 LVAD infections diagnosed 6.5 months after implantation, including 171 (26.2%), 51 (7.8%), and 26 (4.0%) percutaneous driveline infection, pocket infection, or pump/cannula infection, respectively. Patients with infections were aged 58.7 years, and most received HeartMate II (82.1%) or HeartWare (13.4%). Most patients (62%) had implantable cardioverter-defibrillators (ICDs) before LVAD, and 104 (16.0%) had ICD implantation, extraction, or replacement after the LVAD surgery. Main pathogens found among the 248 infections were Staphylococcus aureus (n = 113' 45.4%), Enterobacteriaceae (n = 61; 24.6%), Pseudomonas aeruginosa (n = 34; 13.7%), coagulase-negative staphylococci (n = 13; 5.2%), and Candida species (n = 13; 5.2%). In multivariable analysis, HeartMate II (subhazard ratio, 1.56; 95% CI, 1.03 to 2.36; P = .031) and ICD-related procedures post-LVAD (subhazard ratio, 1.43; 95% CI, 1.03-1.98; P = .031) were significantly associated with LVAD infections. Infections had no detrimental impact on survival. CONCLUSIONS: Left ventricular assist device-associated infections affect one-third of LVAD recipients, mostly related to skin pathogens and gram-negative bacilli, with increased risk with HeartMate II as compared with HeartWare, and in patients who required ICD-related procedures post-LVAD. This is a plea to better select patients needing ICD implantation/replacement after LVAD implantation.

Central venous-to-arterial PCO2 difference, arteriovenous oxygen content and outcome after adult cardiac surgery with cardiopulmonary bypass: A prospective observational study.

BACKGROUND: Rapid identification and treatment of tissue hypoxia reaching anaerobiosis (dysoxia) may reduce organ failure and the occurrence of major postoperative complications (MPC) after cardiac surgery. The predictive ability of PCO2-based dysoxia biomarkers, central venous-to-arterial PCO2 difference (ΔPCO2) and ΔPCO2 to arteriovenous oxygen content difference ratio, is poorly studied in this setting. OBJECTIVES: We evaluated the ability of PCO2-based tissue dysoxia biomarkers, blood lactate concentration and central venous oxygen saturation measured 2 h after admission to the ICU as predictors of MPC. DESIGN: A prospective, observational cohort study. SETTING: Single-centre, academic hospital cardiovascular ICU. PATIENTS: We included adult patients undergoing cardiac surgery with cardiopulmonary bypass and measured dysoxia biomarkers at ICU admission, and after 2, 6 and 24 h. MAIN OUTCOME MEASURES: The primary endpoint was MPC, a composite of cardiac and noncardiac MPC evaluated in the 48 h following surgery. After univariate analysis of MPC covariates including dysoxia biomarkers measured at 2 h, multivariate logistic regression analyses were performed to identify the association of these biomarkers with MPC for confounders. Areas under the receiver operating characteristic curves were determined for biomarkers which remained independently associated with MPC. RESULTS: MPC occurred in 56.5% of the 308 patients analysed. ΔPCO2, blood lactate concentration and central venous oxygen saturation measured at 2 h, but not ΔPCO2 to arteriovenous oxygen content difference ratio, were significantly associated with MPC. However, only ΔPCO2 was independently associated with MPC after multivariate analysis. The areas under the receiver operating characteristic curves of ΔPCO2 measured at 2 h for MPC prediction was 0.64 (95% CI 0.57 to 0.70, P < 0.001). CONCLUSION: After cardiac surgery with cardiopulmonary bypass, ΔPCO2 measured 2 h after ICU admission was the only dysoxia biomarker independently associated with MPC, but with limited performance. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03107572.

Von Willebrand factor as a biological sensor of blood flow to monitor percutaneous aortic valve interventions.

RATIONALE: Percutaneous aortic valve procedures are a major breakthrough in the management of patients with aortic stenosis. Residual gradient and residual aortic regurgitation are major predictors of midterm and long-term outcome after percutaneous aortic valve procedures. We hypothesized that (1) induction/recovery of high molecular weight (HMW) multimers of von Willebrand factor defect could be instantaneous after acute changes in blood flow, (2) a bedside point-of-care assay (platelet function analyzer-closure time adenine DI-phosphate [PFA-CADP]), reflecting HMW multimers changes, could be used to monitor in real-time percutaneous aortic valve procedures. OBJECTIVE: To investigate the time course of HMW multimers changes in models and patients with instantaneous induction/reversal of pathological high shear and its related bedside assessment. METHODS AND RESULTS: We investigated the time course of the induction/recovery of HMW multimers defects under instantaneous changes in shear stress in an aortic stenosis rabbit model and in patients undergoing implantation of a continuous flow left ventricular assist device. We further investigated the recovery of HMW multimers and monitored these changes with PFA-CADP in aortic stenosis patients undergoing transcatheter aortic valve implantation or balloon valvuloplasty. Experiments in the aortic stenosis rabbit model and in left ventricular assist device patients demonstrated that induction/recovery of HMW multimers occurs within 5 minutes. Transcatheter aortic valve implantation patients experienced an acute decrease in shear stress and a recovery of HMW multimers within minutes of implantation which was sustained overtime. In patients with residual high shear or with residual aortic regurgitation, no recovery of HMW multimers was observed. PFA-CADP profiles mimicked HMW multimers recovery both in transcatheter aortic valve implantation patients without aortic regurgitation (correction) and transcatheter aortic valve implantation patients with aortic regurgitation or balloon valvuloplasty patients (no correction). CONCLUSIONS: These results demonstrate that variations in von Willebrand factor multimeric pattern are highly dynamic, occurring within minutes after changes in blood flow. It also demonstrates that PFA-CADP can evaluate in real time the results of transcatheter aortic valve procedures.