German Cardiac Arrest Registry (G-CAR)-results of the pilot phase.

BACKGROUND: In Europe, more than 300,000 persons per year experience out-of-hospital cardiac arrest (OHCA). Despite medical progress, only few patients survive with good neurological outcome. For many issues, evidence from randomized trials is scarce. OHCA often occurs for cardiac causes. Therefore, we established the national, prospective, multicentre German Cardiac Arrest Registry (G-CAR). Herein, we describe the first results of the pilot phase. RESULTS: Over a period of 16 months, 15 centres included 559 consecutive OHCA patients aged ≥ 18 years. The median age of the patients was 66 years (interquartile range 57;75). Layperson resuscitation was performed in 60.5% of all OHCA cases which were not observed by emergency medical services. The initial rhythm was shockable in 46.4%, and 29.1% of patients had ongoing CPR on hospital admission. Main presumed causes of OHCA were acute coronary syndromes (ACS) and/or cardiogenic shock in 54.8%, with ST-elevation myocardial infarction being the most common aetiology (34.6%). In total, 62.9% of the patients underwent coronary angiography; percutaneous coronary intervention (PCI) was performed in 61.4%. Targeted temperature management was performed in 44.5%. Overall in-hospital mortality was 70.5%, with anoxic brain damage being the main presumed cause of death (38.8%). Extracorporeal cardiopulmonary resuscitation (eCPR) was performed in 11.0%. In these patients, the in-hospital mortality rate was 85.2%. CONCLUSIONS: G-CAR is a multicentre German registry for adult OHCA patients with a focus on cardiac and interventional treatment aspects. The results of the 16-month pilot phase are shown herein. In parallel with further analyses, scaling up of G-CAR to a national level is envisaged. Trial registration ClinicalTrials.gov identifier: NCT05142124.

German Experience with a Novel Balloon-Expandable Heart Valve Prosthesis for Transcatheter Aortic Valve Implantation-Outcomes of the MYLAND (MYvaL germAN stuDy) Study.

Background: The primary objective of this study was to evaluate the initial experience in Germany with the Meril Myval™ (MM) transcatheter heart valve (THV) system for the treatment of severe symptomatic aortic valve stenosis. The MM THV is a novel balloon-expandable valve with an expanded sizing matrix. Contemporary patients undergoing TAVI with the established Edwards Sapien™ (ES) THV served as the comparator group. Methods: Between 1st March and 31 August 2020 a total of 134 patients (33% female, 80.1 ± 6.7 years; EuroScore II 4.7 ± 4.8) underwent TAVI with an MM (95% transfemoral) for severe aortic stenosis at six German tertiary care centers. Results: Correct positioning of the THV was achieved in 98.5% (n = 132). Mean aortic gradients (MPG) were reduced from 42 ± 14 mmHg to 11 ± 5 mmHg. Mild postprocedural paravalvular leak (PVL) was observed in 62% (n = 82) patients, whereas only one patient had more than mild PVL. New permanent pacemaker implantation (PPI) was indicated in 15 patients (11%). Major vascular complications occurred in 6.7% (n = 9) patients. The in-hospital combined incidence of all-cause death and stroke was 4.5% (n = 6). In the comparator group that included 268 patients, the 30-day incidences of PPI, major vascular complications, and the composite of all-cause death and stroke were 16%, 1.9%, and 7.1%, respectively; MPGs were reduced from 44 ± 15 mmHg to 12.8 ± 4.6 mmHg and the more than mild PVL occurred in 0.7%. Conclusions: The MM is a promising novel THV system, with performance comparable to the established ES THVs. These findings await confirmation by ongoing randomized trials.

[Extracorporeal Cardiopulmonary Resuscitation(ECPR) - the Future?] / Extrakorporale kardiopulmonale Reanimation (ECPR) ­ die Zukunft?

In recent years, invasive resuscitation methods utilizing veno-arterial extracorporeal membrane oxygenation (VA-ECMO) have gained significant attention. Despite advances in traditional resuscitation measures, out-of-hospital cardiac arrest (OHCA) mortality remains high. In the context of extracorporeal cardiopulmonary resuscitation (ECPR), VA-ECMO therapy offers a promising approach by providing circulatory support during cardiac arrest, allowing time for diagnostic evaluation and targeted therapy. However, patient selection for ECPR remains a challenge, relying on various factors including initial rhythm, duration of no-flow and low-flow states, as well as presence of reversible causes.Recent studies such as the ARREST, Prague OHCA and INCEPTION trials have investigated the efficacy of ECPR in OHCA patients, yielding mixed results. While the ARREST trial demonstrated a survival benefit with ECPR, the Prague OHCA and INCEPTION trials showed varying outcomes, reflecting the complexity of patient selection and treatment strategies. Despite inherent risks and complications associated with ECPR, it may offer a potential survival advantage under optimal conditions.Future directions in ECPR involve the development of innovative treatment protocols such as the CARL therapy, which incorporates specialized ECMO systems and tailored perfusion solutions. Early studies indicate promising outcomes with CARL therapy, emphasizing the importance of a well-coordinated and structured approach to ECPR implementation.In summary, ECPR shows promise in improving survival rates for OHCA patients within a well-organized healthcare system. However, further research is needed to refine patient selection criteria and optimize treatment protocols, ultimately enhancing patient outcomes in cardiac arrest scenarios.

Extracorporeal Life Support in Infarct-Related Cardiogenic Shock.

BACKGROUND: Extracorporeal life support (ECLS) is increasingly used in the treatment of infarct-related cardiogenic shock despite a lack of evidence regarding its effect on mortality. METHODS: In this multicenter trial, patients with acute myocardial infarction complicated by cardiogenic shock for whom early revascularization was planned were randomly assigned to receive early ECLS plus usual medical treatment (ECLS group) or usual medical treatment alone (control group). The primary outcome was death from any cause at 30 days. Safety outcomes included bleeding, stroke, and peripheral vascular complications warranting interventional or surgical therapy. RESULTS: A total of 420 patients underwent randomization, and 417 patients were included in final analyses. At 30 days, death from any cause had occurred in 100 of 209 patients (47.8%) in the ECLS group and in 102 of 208 patients (49.0%) in the control group (relative risk, 0.98; 95% confidence interval [CI], 0.80 to 1.19; P = 0.81). The median duration of mechanical ventilation was 7 days (interquartile range, 4 to 12) in the ECLS group and 5 days (interquartile range, 3 to 9) in the control group (median difference, 1 day; 95% CI, 0 to 2). The safety outcome consisting of moderate or severe bleeding occurred in 23.4% of the patients in the ECLS group and in 9.6% of those in the control group (relative risk, 2.44; 95% CI, 1.50 to 3.95); peripheral vascular complications warranting intervention occurred in 11.0% and 3.8%, respectively (relative risk, 2.86; 95% CI, 1.31 to 6.25). CONCLUSIONS: In patients with acute myocardial infarction complicated by cardiogenic shock with planned early revascularization, the risk of death from any cause at the 30-day follow-up was not lower among the patients who received ECLS therapy than among those who received medical therapy alone. (Funded by the Else Kröner Fresenius Foundation and others; ECLS-SHOCK ClinicalTrials.gov number, NCT03637205.).

[ECMO support during the first two waves of the corona pandemic-a survey of high case volume centers in Germany]. / ECMO-Unterstützung während der ersten 2 Wellen der Coronapandemie ­ eine Umfrage an Zentren mit hohen Fallzahlen in Deutschland.

BACKGROUND: At the onset of the coronavirus pandemic, concerns were raised about sufficiency of available intensive care resources. In many places, routine interventions were postponed and criteria for the allocation of scarce resources were formulated. In Germany, some hospitals were at times seriously burdened during the course of the pandemic. Intensive care units in particular experienced a shortage of resources, which may have led to a restriction of services and a stricter indication setting for resource-intensive measures such as extracorporeal membrane oxygenation (ECMO). The aim of this work is to provide an overview of how these pressures were managed at large ECMO centers in Germany. METHODS: One representative of each major ECMO referral center in Germany was invited to participate in an online survey in spring 2021. RESULTS: Of 34 invitations that were sent out, the survey was answered by 23 participants. In all centers, routine procedures were postponed during the pandemic. Half of the centers increased the number of beds on which ECMO procedures could be offered. Nevertheless, in one-third of the centers, the start of at least one ECMO support was delayed because of a feared resource shortage. In 17% of centers, at least one patient was denied ECMO that he or she would have most likely received under prepandemic conditions. CONCLUSION: The results of this online survey indicate that the experienced pressures and resource constraints led some centers to be cautious about ECMO indications.

Treatment of Refractory Cardiac Arrest by Controlled Reperfusion of the Whole Body: A Multicenter, Prospective Observational Study.

Background: Survival following cardiac arrest (CA) remains poor after conventional cardiopulmonary resuscitation (CCPR) (6-26%), and the outcomes after extracorporeal cardiopulmonary resuscitation (ECPR) are often inconsistent. Poor survival is a consequence of CA, low-flow states during CCPR, multi-organ injury, insufficient monitoring, and delayed treatment of the causative condition. We developed a new strategy to address these issues. Methods: This all-comers, multicenter, prospective observational study (69 patients with in- and out-of-hospital CA (IHCA and OHCA) after prolonged refractory CCPR) focused on extracorporeal cardiopulmonary support, comprehensive monitoring, multi-organ repair, and the potential for out-of-hospital cannulation and treatment. Result: The overall survival rate at hospital discharge was 42.0%, and a favorable neurological outcome (CPC 1+2) at 90 days was achieved for 79.3% of survivors (CPC 1+2 survival 33%). IHCA survival was very favorable (51.7%), as was CPC 1+2 survival at 90 days (41%). Survival of OHCA patients was 35% and CPC 1+2 survival at 90 days was 28%. The subgroup of OHCA patients with pre-hospital cannulation showed a superior survival rate of 57.1%. Conclusions: This new strategy focusing on repairing damage to multiple organs appears to improve outcomes after CA, and these findings should provide a sound basis for further research in this area.

Sleep apnea predicts cardiovascular death in patients with Marfan syndrome: a cohort study.

Background: Surgical replacement of the aortic root is the only intervention that can prevent aortic dissection and cardiovascular death in Marfan syndrome (MFS). However, in some individuals, MFS also causes sleep apnea. If sleep apnea predicts cardiovascular death, a new target for predictive, preventive, and personalized medicine (PPPM) may emerge for those individuals with MFS who have sleep apnea. Methods: This is an investigator-initiated study with long-term follow-up data of 105 individuals with MFS. All individuals were screened for sleep apnea regardless of symptoms. Cardiovascular death served as a primary endpoint, and aortic events as a secondary outcome. Results: Sleep apnea with an apnea-hypopnea index (AHI) > 5/h was observed in 21.0% (22/105) with mild sleep apnea in 13% (14/105) and moderate to severe sleep apnea in 7.6% (8/105). After a median follow-up of 7.76 years (interquartile range: 6.84, 8.41), 10% (10/105) had died, with cardiovascular cause of death in 80% (8/10). After adjusting for age and body mass index (BMI), the AHI score emerged as an independent risk factor for cardiovascular death (hazard ratio 1.712, 95% confidence interval [1.061-2.761], p = 0.0276). The secondary outcome of aortic events occurred in 33% (35/105). There was no effect of the AHI score on aortic events after adjusting for age and BMI (hazard ratio 0.965, 95% confidence interval [0.617-1.509]), possibly due to a high number of patients with prior aortic surgery. Interpretation: Sleep apnea is emerging as an independent predictor of cardiovascular death in MFS. It seems mandatory to screen all individuals with MFS for sleep apnea and to include these individuals, with both MFS and sleep apnea, in further studies to evaluate the impact of preventive measures with regard to cardiovascular death. Supplementary Information: The online version contains supplementary material available at 10.1007/s13167-022-00291-4.

Comprehensive echocardiographic prediction of postprocedural transmitral pressure gradient following transcatheter mitral valve repair.

Iatrogenic mitral stenosis following transcatheter mitral valve repair (TMVR) for relevant mitral regurgitation (MR) is a potential adverse side-effect, known to affect long-term outcome. However, only few determinants of an elevated mean transmitral pressure gradient (TMPG) have been described thus far. We sought to develop an integrative model for the prediction of TMPG following MitraClip (MC) therapy. From 01/2013 to 03/2017, a total of 175 consecutive patients were successfully (MR ≤ 2 + at discharge) treated with a MitraClip implantation at our centre. Of these, a total of 148 patients (54% male, 77.0 ± 6.0 years, 58% with secondary MR) had complete echocardiographic data sets comprising pre- and postinterventional two- and three-dimensional transthoracic (TTE) and transoesophageal (TOE) echocardiograms. Comprehensive studies of predefined parameters were performed. An expert-based prediction model including preprocedural variables (annular ellipticity, mitral valve commissure-to-commissure diameter, preprocedural transmitral pressure gradient and MR aetiology) was set up and validated with a total of 200 bootstrap samples. A nomogram was developed to predict the postprocedural TMPG based on selected echocardiographic variables. Introduction of nomogram-based guiding of MC therapy could help identify patients at risk for postprocedural mitral stenosis, have an influence on preprocedural patient selection and intraprocedural decision making.

Short-term use of "ECMELLA" in the context of fulminant eosinophilic myocarditis with cardiogenic shock.

BACKGROUND: Eosinophilic myocarditis (EM) is a rare form of myocarditis. Clinical presentation is various, includes cardiogenic shock and can often be fatal. Diagnosis is based on myocardial eosinophilic infiltration in endomyocardial biopsy. Mechanical circulatory support (MCS) is often required in patients suffering from severe cardiogenic shock. Among the available MCS options the "ECMELLA" concept, a combination of left ventricular venting by Impella® device and extracorporeal life support (ECLS) is possibly able to provide the necessary time frame for diagnostics and initiation of anti-inflammatory medication in patients with fulminant myocarditis. CASE PRESENTATION: We report a case of a 38-year-old woman who was presented to us in severe cardiogenic shock, quickly requiring hemodynamic support by an Impella CP® device. Further dramatic hemodynamic deterioration accompanied by multi-organ dysfunction required escalation of MCS via ECLS as veno-arterial extracorporeal membrane oxygenation (VA-ECMO). After histopathological diagnosis of EM, our patient was put on immunosuppressive therapy with prednisolone. Recovery of both right and left ventricular function allowed explanation of VA-ECMO on day 4 and further hemodynamic improvement allowed removal of the Impella® device on day 9. The patient was discharged after 7 weeks with fully restored cardiac function and in a good neurological state. CONCLUSIONS: In severe cardiac shock due to fulminant EM the ECMELLA concept as bridge-to-recovery seems to be a valid option to provide the required time for diagnostics and specific therapy.

The impact of residual mitral regurgitation after MitraClip therapy in functional mitral regurgitation.

AIMS: MitraClip therapy for the treatment of functional mitral regurgitation (FMR) is an increasingly used intervention for high-risk surgical patients. The aim of this observational study was to assess the impact of residual mitral regurgitation (rMR) at discharge on long-term outcome after MitraClip therapy in patients with FMR. METHODS AND RESULTS: Overall, 458 patients (mean age 73.8 ± 8.9 years) underwent MitraClip implantation between September 2008 and December 2017. The impact of rMR ≤ 1+ at discharge (n = 251) was retrospectively compared to patients graded as rMR 2+ (n = 173) and rMR ≥3+ (n = 34) at discharge. Median follow-up time was 5.09 years (5.00-5.26) with maximum follow-up of 10.02 years. The primary outcome was survival, and Kaplan-Meier analyses revealed significant differences among all rMR subgroups with highest survival rates for rMR ≤ 1+ patients. This was further confirmed by composite outcome analyses (P < 0.02). The inferior outcomes of rMR 2+ and rMR ≥ 3+ at discharge were confirmed by increased adjusted hazard ratios when rMR 2+ (1.54, P = 0.0039) and rMR ≥ 3+ (2.16, P = 0.011) were compared to rMR ≤ 1+. Moreover, patients with stable rMR ≤ 1+ grades within 12 months showed significantly higher survival rates compared to patients with rMR ≤ 1+ at discharge and rMR ≥ 2+ at 12-month follow-up or rMR ≥ 2+ at discharge and 12-month follow-up (P = 0.029). CONCLUSIONS: Patients with optimal and durable rMR ≤ 1+ at discharge and 12-month follow-up showed better outcome compared to patients with rMR 2+ and rMR ≥ 3+. Treatment success and durability characterized by rMR ≤ 1+ at discharge and 12 months seem to be important factors for long-term outcomes, which has to be further confirmed by prospective randomized trials.

Underweight is associated with inferior short and long-term outcomes after MitraClip implantation: Results from the German TRAnscatheter mitral valve interventions (TRAMI) registry.

BACKGROUND: Underweight and obesity represent classical risk factors for adverse outcome in patients treated for cardiovascular disease. AIMS: The current analysis examines the impact of underweight, overweight and obesity on intra-hospital, short and long-term outcomes in patients treated by MitraClip therapy. METHODS AND RESULTS: From August 2010 until July 2013, 799 patients (age 75.3 ±â€¯8.6 years, male gender 60.7%, median logistic EuroSCORE 20% [12; 31], functional mitral regurgitation (MR): 69.3%) were prospectively enrolled into the multicenter German Transcatheter Mitral Valve Interventions registry. Patients were stratified according to body mass index (BMI) into 4 groups: BMI <20 kg/m2 (underweight), BMI 20.0 to <25.0 kg/m2 (normal weight, reference group), BMI 25.0 to <30.0 kg/m2 (overweight) and BMI ≥30 kg/m2 (obese). Significant increased rates of procedural failure, transfusion/bleeding, sepsis or multiorgan failure and low cardiac output failure were found for underweight patients only. Kaplan-Meier survival curves demonstrated inferior survival for underweight patients, but comparable outcomes for all other patients (global log rank test, P < .01). Multivariable Cox-regression analysis (adjusted for age, gender, creatinine ≥1.5 mg/dL, diabetes, left ventricular ejection fraction <30% and chronic obstructive pulmonary disease) confirmed underweight (as compared to normal weight) as an independent risk factor of death (hazard ratio [HR]: 1.58, 95% confidence interval (CI): 1.01-2.46, P = .044) and overweight as protective against death (HR: 0.71; 95%-CI: 0.55-0.93; P = .011). CONCLUSIONS: Compared to other weight groups, underweight patients undergoing MitraClip implantation are exposed to increased rates of procedural failure, bleeding and low cardiac output as well as increased short- and long-term mortality rates and should therefore be carefully discussed in the heart-team.

Association between optical coherence tomography based retinal microvasculature characteristics and myocardial infarction in young men.

Incident myocardial infarction (MI) is a leading cause of adult mortality in the United States. However, because MI has a relatively low incidence in the young population, little information exists on the disease in younger adults. Because the retina has the unique quality that its vasculature is readily and noninvasively visible, the retina is frequently studied to evaluate correlations between vessels and cardiovascular diseases. In the current study, we evaluated the retinal microvasculature of patients who had experienced an MI before 50 years of age (n = 53 subjects) and age- and sex-matched patients who had not experienced an MI (n = 53 patients). We used circular optical coherence tomography (OCT) scans to image peripapillary venules and arterioles. The diameter of each vessel was measured and the respective arterial-venous ratio (AVR) was calculated. We did not detect any significant differences between MI and control subjects in retinal vessel calibre or AVR.

Implication of pulmonary hypertension in patients undergoing MitraClip therapy: results from the German transcatheter mitral valve interventions (TRAMI) registry.

AIMS: We sought to evaluate the impact of pulmonary hypertension on outcomes following MitraClip therapy. METHODS AND RESULTS: The 643 patients in the TRAnscatheter Mitral valve Interventions (TRAMI) registry were divided into three groups according to echocardiographically graded systolic pulmonary artery pressure (sPAP) (Group 1: patients with sPAP of ≤36 mmHg; Group 2: patients with sPAP of 37-50 mmHg; Group 3: patients with sPAP of >50 mmHg) and followed for 1 year. Recent cardiac decompensation, aortic valve disease and tricuspid valve insufficiency were observed more frequently in patients with higher sPAP. Furthermore, logEuroSCORE, Society of Thoracic Surgeons score and age were higher with rising sPAP values. No differences were observed in mitral regurgitation (MR) severity, co-morbidities or clinical findings (New York Heart Association class, 6-min walking distance). Reduction to MR of grade 1 or lower was achieved more often in patients with lower sPAP levels (P = 0.01). In Groups 2 and 3, sPAP was reduced significantly. Major adverse cardiac or cardiovascular events (MACCEs) occurring in hospital (death, myocardial infarction, stroke; <4% in each group), as well as 30-day rates of MACCEs (6.1% in Group 1, 11.9% in Group 2, 12.4% in Group 3) and rehospitalization (18.9% in Group 1, 24.8% in Group 2, 24.8% in Group 3) did not differ significantly. At 1 year, differences in rates of mortality and MACCEs (20.3% in Group 1, 33.1% in Group 2, 34.7% in Group 3; P < 0.01) were significant. Both Groups 2 [hazard ratio (HR) 1.81, P = 0.0122] and 3 (HR 1.85, P = 0.0092) were independently predictive of death. Rehospitalization rates did not differ during follow-up. CONCLUSIONS: Despite higher mortality in patients with elevated sPAP, these data suggest the safety, feasibility and benefit of MitraClip therapy even in advanced stages of disease. An early approach might prevent the progress of pulmonary hypertension and improve outcomes.

Distinct Hemodynamic Changes After Interventional Mitral Valve Edge-to-Edge Repair in Different Phenotypes of Heart Failure: An Integrated Hemodynamic Analysis.

BACKGROUND: Percutaneous mitral valve edge-to-edge repair (pMVR) with a MitraClip is beneficial for the clinical symptoms of patients irrespective of the ejection fraction (EF). Nevertheless, the consequences on hemodynamics are poorly understood. Therefore, we used data from noninvasive pressure-volume loops to investigate the left ventricular (LV) remodeling of patients after pMVR dependent on their baseline EF. METHODS AND RESULTS: In 130 patients with successful pMVR, the end-diastolic pressure-volume relationship (EDPVR) and end-systolic pressure-volume relationship were estimated noninvasively from echocardiographic data. We compared EDPVR and end-systolic pressure-volume relationship at discharge and follow-up between patients with a reduced EF (<40%) and patients with a mid-ranged or preserved EF (≥40%). Reduced EF was present in 71 patients (54%). Mean follow-up duration was 277±117 days. We observed a significant reduction in degree of mitral regurgitation and an improvement in functional status at follow-up irrespective of baseline EF. In patients with a mid-ranged or preserved EF, the EDPVR and end-systolic pressure-volume relationship were shifted leftwards, suggesting an improvement in LV function. In contrast, in patients with a reduced EF, EDPVR and end-systolic pressure-volume relationship remained stable, although comparison with the baseline data indicates a rightward shift of the EDPVR. This indicates that there is no improvement in LV function after pMVR in patients with reduced EF. CONCLUSIONS: The pMVR is associated with improved clinical symptoms in all patient subgroups. However, it leads to different hemodynamic responses. In patients with mid-ranged or preserved EF, we found reverse remodeling with reduced LV dilatation and increased contractility. In contrast, in patients with reduced EF, we observed no reverse remodeling and no improvement in LV function.

Transcatheter Mitral Valve Repair in Surgical High-Risk Patients: Gender-Specific Acute and Long-Term Outcomes.

BACKGROUND: Analyses emphasizing gender-related differences in acute and long-term outcomes following MitraClip therapy for significant mitral regurgitation (MR) are rare. METHODS: 592 consecutive patients (75 ± 8.7 years, 362 men, 230 women) underwent clinical and echocardiographic follow-up for a median of 2.13 (0.99-4.02) years. RESULTS: Significantly higher prevalence of cardiovascular comorbidities, renal failure, and adverse echocardiographic parameters in men resulted in longer device time (p = 0.007) and higher numbers of implanted clips (p = 0.0075), with equal procedural success (p = 1.0). Rehospitalization for heart failure did not differ (p[logrank] = 0.288) while survival was higher in women (p[logrank] = 0.0317). Logarithmic increase of NT-proBNP was a common independent predictor of death. Hypercholesterolemia and peripheral artery disease were predictors of death only in men while ischemic and dilative cardiomyopathy (CM) and age were predictors in women. Independent predictors of rehospitalization for heart failure were severely reduced ejection fraction and success in men while both ischemic and dilative CM, logistic EuroSCORE, and MR severity were predictive in women. CONCLUSIONS: Higher numbers of implanted clips and longer device time are likely related to more comorbidities in men. Procedural success and acute and mid-term clinical outcomes were equal. Superior survival for women in long-term analysis is presumably attributable to a comparatively better preprocedural health.

In vivo proliferation of hepadnavirus-infected hepatocytes induces loss of covalently closed circular DNA in mice.

UNLABELLED: Chronic hepatitis B virus (HBV) infection is maintained by the presence of covalently closed circular DNA (cccDNA), the template of viral transcription and replication. In quiescent hepatocytes, cccDNA is a stable molecule that can persist throughout the hepatocyte lifespan. However, in chronic HBV infection, immunomediated cell injury and compensatory hepatocyte proliferation may favor cccDNA decline and selection of cccDNA-free cells. To investigate the impact of liver regeneration on cccDNA stability and activity in vivo, we used the urokinase-type plasminogen activator (uPA)/severe combined immunodeficiency (SCID) mouse model. Primary tupaia hepatocytes (PTHs) chronically infected with woolly monkey HBV (WM-HBV) were isolated from one highly viremic uPA/SCID chimeric mouse and transplanted into 20 uPA recipients. Expansion of transplanted PTHs and viral load changes were determined by real-time polymerase chain reaction and immunohistochemistry. Transplantation of WM-HBV infected hepatocytes led to an average of 3.8 PTH doublings within 80 days, 75% reduction of virion productivity (relaxed circular DNA/cccDNA), and lower expression levels of pregenomic RNA and hepatitis B core antigen. Remarkably, a median 2-log decline of cccDNA per cell determined during PTH proliferation was due to both dilution of the cccDNA pool among daughter cells and a 0.5-log loss of intrahepatic cccDNA loads (P = 0.02). Intrahepatic viral DNA sequences persisting at the end of the study were mostly present as replicative intermediates and not as integrated virus. CONCLUSION: Cell division in the setting of liver regeneration and without administration of antiviral drugs induced strong destabilization of the cccDNA reservoir, resulting in cccDNA clearance in the great majority of chronically infected hepatocytes.