Impact of patient-prosthesis mismatch on long-term outcomes after aortic valve replacement.

BACKGROUND: Patient-prosthesis mismatch (PPM) after aortic valve replacement potentially affects the outcome after the operation. This study sought to determine whether PPM has an impact on long- term mortality and reoperation rates. METHODS: We included 645 patients who underwent biological aortic valve replacement between 2000 and 2007. Based on echocardiographic examinations at postoperative month six, the incidence of PPM was determined according to an indexed effective orifice area < 0.85 m2/cm2. Survival and reoperation status were analyzed over 15 years of follow-up. RESULTS: PPM was present in 256 patients (40%), of whom 175 had moderate and 81 severe PPM. In multivariable-adjusted analysis, survival was not statistically significantly impaired in patients with moderate PPM compared to no PPM, whereas severe PPM showed a marginally significant impairment of survival (Hazard Ratio (HR) 1.40 (95% Confidence Interval (CI) 0,99-1,97; p=0.054). Risk factors for survival were higher age (HR 1.12 (95% C.I. 1.10-1.14; p<0.001), arterial hypertension (HR 1.78 (95% C.I. 1.38-2.31; p<0.001), and diabetes mellitus (HR 1.67 (95% C.I 1.31-2.14; p<0.001). In patients with no, moderate and severe PPM, there were 10.1, 8.5, and 14.8 events of reoperation/1000 patient-years, respectively. The corresponding 10-year cumulative incidence of reoperation was 8.3%, 6.7%, and 12.1%, respectively. In multivariable-adjusted analysis, PPM category was not significantly associated with the risk of reoperation (p>0.2). CONCLUSIONS: In our study with directly measured effective orifice area, PPM was only marginally related to long-term survival and was not statistically significantly associated with the risk of reintervention.

Incidence of Prosthesis-Patient Mismatch in Valve-in-Valve with a Supra-Annular Valve.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) for a degenerated surgical bioprosthesis (valve-in-valve [ViV]) has become an established procedure. Elevated gradients and patient-prosthesis mismatch (PPM) have previously been reported in mixed TAVR cohorts. We analyzed our single-center experience using the third-generation self-expanding Medtronic Evolut R prosthesis, with an emphasis on the incidence and outcomes of PPM. METHODS: This is a retrospective analysis of prospectively collected data from our TAVR database. Intraprocedural and intrahospital outcomes are reported. RESULTS: Eighty-six patients underwent ViV-TAVR with the Evolut R prosthesis. Mean age was 75.5 ± 9.5 years, 64% were males. The mean log EuroScore was 21.6 ± 15.7%. The mean time between initial surgical valve implantation and ViV-TAVR was 8.8 ± 3.2 years. The mean true internal diameter of the implanted surgical valves was 20.9 ± 2.2 mm. Post-AVR, 60% had no PPM, 34% had moderate PPM, and 6% had severe PPM. After ViV-TAVR, 33% had no PPM, 29% had moderate, and 39% had severe PPM. After implantation, the mean transvalvular gradient was reduced significantly from 36.4 ± 15.2 to 15.5 ± 9.1 mm Hg (p < 0.001). No patient had more than mild aortic regurgitation after ViV-TAVR. No conversion to surgery was necessary. Estimated Kaplan-Meier survival at 1 year for all patients was 87.4%. One-year survival showed no significant difference according to post-ViV PPM groups (p = 0.356). CONCLUSION: ViV-TAVR using a supra-annular valve resulted in low procedural and in-hospital complication rates. However, moderate or severe PPM was common, with no influence on short-term survival. PPM may not be a suitable factor to predict survival after ViV-TAVR.

AVNeo improves early haemodynamics in regurgitant bicuspid aortic valves compared to aortic valve repair.

OBJECTIVES: Calcified or fibrotic cusps in patients with bicuspid aortic valves and aortic regurgitation complicate successful aortic valve (AV)-repair. Aortic valve neocuspidization (AVNeo) with autologous pericardium offers an alternative treatment to prosthetic valve replacement. We compared patients with regurgitant bicuspid valves undergoing AV-repair or AVNeo. METHODS: We retrospectively analysed patients with regurgitant bicuspid valves undergoing AV-repair or AVNeo. We focused on residual regurgitation, pressure gradients and effective orifice area, determined preoperatively and at discharge. RESULTS: AV-repair was performed in 61 patients (mean age: 43.2 ± 11.3 years) and AVNeo in 22 (45.7 ± 14.1). Prior to the operation patients of the AV-repair group showed severe regurgitation in 38 cases (62.3%) and moderate in 23 (37.6%); in the AVNeo group, all patients exhibited severe regurgitation. Postoperatively, 57 patients (93.4%) patients had no or mild regurgitation after AV-repair and 21 (95.4%) after AVNeo. In AVNeo-patients, peak (10.6 ± 3.1 mmHg vs 22.7 ± 11 mmHg, P< 0.001) and mean pressure gradients (5.9 ± 2 mmHg vs 13.8 ± 7.3 mmHg, P < 0.001) were significantly lower and the orifice area significantly larger (2.9 ± 0.8 cm2 vs 1.9 ± 0.7 cm2, P < 0.001) compared to repair. CONCLUSIONS: Compared to AV-repair, patients AVNeo showed lower mean pressure gradients and larger orifice areas at discharge. The functional result was not different.

Aortic valve neocuspidization using autologous pericardium compared to surgical aortic valve replacement.

INTRODUCTION: Aortic valve neocuspidization (AVNeo) for trileaflet aortic valve reconstruction using autologous pericardium (Ozaki procedure) depicts an encouraging new technique for the surgical treatment of aortic valve pathologies. The current study analyzes the early hemodynamic outcome of AVneo compared with surgical aortic valve replacement (SAVR) using the Abbott/St. Jude Trifecta aortic valve biological prostheses. METHODS: All patients who underwent either AVNeo or SAVR between March 2017 and April 2020 were included. Exclusion criteria were emergency cases, endocarditis, redo- or additional root procedures. Main endpoints were differences between the two groups in terms of the effective orifice area (EOA) and the effective orifice area index (EOAI) at discharge. RESULTS: During the study period, 105 AVNeo patients and 458 SAVR patients met the inclusion criteria. EOA was significantly higher in the AVNeo group (2.4 cm2 ± 0.8 vs. 2.1 cm2 /m2 ± 0.6 in the SAVR group, respectively; p < .001). Multiple regression analysis, including AVNeo, annulus size, bicuspid valve, preoperative stenosis, left ventricular ejection fraction (LVEF), and diastolic diameter (LVEDD) found two factors, which favor larger EOA: Annulus size (p < .0001) and AVneo (p = .005). EOAI was significantly higher in the AVNeo group (1.23 ± 0.4 vs. 1.02 cm2 /m2 ± 0.3, respectively; p < .001). Multiple regression analysis for EOAI showed effects for AVneo (p = .005) and bicuspid valve (p = .029). Mean pressure gradients (MPG) were lower in the AVNeo group than in the SAVR group (AVNeo: MPG = 8.0 mmHg ± 3.6 vs. SAVR: MPG = 8.3 mmHg ± 3.6), but this finding did not reach statistical significance (p = .091). CONCLUSIONS: AVNeo shows significantly larger EOA and EOAI compared to SAVR using the Abbott/St. Jude Trifecta aortic valve biological prostheses.

Serial echocardiographic evaluation of the Perimount Magna Ease prosthesis.

BACKGROUND: The Carpentier-Edwards Perimount Magna Ease prosthesis (PME) represents the latest generation of stented bioprostheses used for surgical aortic valve replacement (SAVR). The aim of our study was to evaluate the long-term clinical outcome and hemodynamic performance of the prosthesis with a focus on the incidence and course of structural valve deterioration (SVD) by serial echocardiographic examinations. METHODS: SAVR with the PME was performed in 58 consecutive patients between 2007 and 2008. Transthoracic echocardiography was performed preoperatively, at discharge and annually during a 10-year follow-up at the German Heart Center Munich. RESULTS: Mean age at surgery was 62±14 years. At discharge (n=57), the overall mean pressure gradient (MPG) and effective orifice area (EOA) were 15.8±4.1 mmHg and 1.8±0.4 cm2, respectively. Moderate patient-prosthesis mismatch (PPM) was present in 18 patients (32%) and severe PPM in 6 patients (11%) at discharge. Ten years following SAVR (n=33), the overall MPG was 16.6±7.3 mmHg and EOA was 1.3±0.4 cm2.Thirty-day and late mortality was 2% (n=1) and 21% (n=12), respectively. Survival at 1, 5, and 10 years was 94.7%±3.3%, 91.1%±4.1%, and 77.3%±5.9%, respectively. Freedom from reoperation at 10 years was 88.8%±4.7%. Ten years after PME implantation the cumulative incidence of any SVD, severe SVD, and bioprosthetic valve failure (BVF) was 25%±6%, 14%±5%, and 16%±5%, respectively. CONCLUSIONS: The PME shows an excellent hemodynamic performance over the course of 10 years with development of clinically relevant SVD as late as 6 years post implant, and a 10-year incidence of severe SVD of 14%.

Mitral valve repair with the edge-to-edge technique: A 20 years single-center experience.

OBJECTIVES: For tailored treatment of primary mitral regurgitation (MR), surgeons developed different repair techniques. One of them, the edge-to-edge repair has recently seen a revival, especially for Barlow's disease. METHODS: This study was designed to assess the outcomes of the edge-to-edge technique in mitral valve (MV) repair. Preoperative, periprocedural, and postoperative data were prospectively collected in a dedicated database and analyzed retrospectively. RESULTS: Between March 1999 and July 2019, a total of 152 patients (mean age: 60 ± 13) received an edge-to-edge repair combined with annuloplasty for degenerative MR at our institution. MR resulted from posterior leaflet prolapse in 23 patients (15.1%), anterior leaflet prolapse in 19 (12.5%), and bileaflet prolapse in 110 (72.4%). Of those who had a bileaflet prolapse, 91 (82.7%) had Barlow's disease. Follow-up was complete in 97.4% (6.4 ± 5.7 years). Echocardiographic assessment was achieved in 85.5% (5.1 ± 5.6 years). Overall survival after 10 years was 73.7 ± 5.0%. Twelve patients required valve-related reoperations due to ring dehiscence (n = 2), leaflet suture dehiscence (n = 2), progression of native valve disease (n = 6), or due to device failure (ring fracture) (n = 2). The cumulative incidence of valve-related reoperation at 10 years was 8.4 ± 3.0% (5.2 ± 4.1% in patients with Barlow's disease). At latest follow-up, echocardiography revealed excellent valve function with no or mild MR in 93 patients (88.6%). The mean gradient was 2.9 ± 1.3 mmHg at discharge and decreased to 2.4 ± 1.3 mmHg. Three patients (2.8%) had more than moderate MR. CONCLUSION: Edge-to-edge MV repair is a simple method with excellent results in terms of valvular function and durability especially in patients with Barlow's disease.

Excellent Hemodynamic Performance After Aortic Valve Neocuspidization Using Autologous Pericardium.

BACKGROUND: Aortic valve neocuspidization (AVNeo) for trileaflet aortic valve reconstruction using autologous pericardium (Ozaki procedure) offers an alternative treatment modality to overcome drawbacks of conventional prosthetic aortic valve replacement. METHODS: Between October 2016 and April 2019, 103 patients underwent surgery. Mean follow-up was 426 ± 270 days. Aortic stenosis was the leading diagnosis in 80 patients (77.7%) and aortic regurgitation in 23 (22.3%), respectively. Mean age was 54.0 ± 16.4 years (range, 13.8-78.5). A bicuspid valve was found in 81 patients (78.6%). Transthoracic echocardiography was performed at discharge and at 6 to 12 months after surgery. During AVNeo surgery valve sizing for an Abbott/St Jude Trifecta bioprosthesis (virtually implanted Trifecta bioprosthesis; St Jude Medical, St Paul, MN) was performed to compare pressure gradients and effective orifice area with published data. RESULTS: Trileaflet aortic valve reconstruction was achieved in all patients. In 38 patients neocommissures were created (36.9%). Mean cross-clamp time was 135 ± 20 minutes. Four patients underwent reoperation; the overall freedom from reoperation was 96.1%. Echocardiographic 6- to 12-months follow-up after surgery was available in 93.8% of patients and did not show any change in hemodynamic parameters compared with discharge. Comparison between AVNeo and virtually implanted Trifecta Bioprosthesis revealed a significantly lower mean pressure gradient (8.5 ± 3.7 mm Hg vs 10.2 ± 2.0 mm Hg, P < .001) and higher mean effective orifice area (2.2 ± 0.7 cm2 vs 2.1 ± 0.4 cm2, P = .037) for AVNeo. CONCLUSIONS: AVNeo shows low reoperation rates after surgery within the first 2 years. The hemodynamic performance is excellent, and the effective orifice area and mean pressure gradient remain stable within the first year.

Clostridioides (Clostridium) difficile Pacemaker Infection.

Clostridioides difficile is the leading cause of antibiotic-associated nosocomial diarrhea, but extra-intestinal manifestations are rare. We describe the first documented case of bacteraemia with pacemaker pocket and lead infection with the toxigenic C. difficile ribotype 014 with a lack of abdominal symptoms. The patient underwent pacemaker extraction and treatment with intravenous and oral vancomycin. Genotyping and molecular subtyping revealed clonality between pacemaker and intestinal isolates. This case illustrates the risk of intravascular device infections due to C. difficile. Even asymptomatic C. difficile colonization might pose a risk for prosthetic material infection.

Comparison of outcomes following isolated repair of tricuspid versus bicuspid aortic valves.

BACKGROUND: Aortic valve repair (AV-repair) is an alternative treatment option for patients with aortic regurgitation (AR), but durability is still reason for concern, especially for bicuspid aortic valves (BAV). We retrospectively evaluated mid-term results after AV-repair in patients with BAV or tricuspid aortic valves (TAV), including reoperation rates, recurrence of regurgitation, and survival. METHODS: Patients undergoing AV-repair between November 2004 and March 2016 without procedures involving the aortic root were included. Echocardiographic examinations were performed before and after the operation and at follow-up. Repair techniques were recorded and evaluated. RESULTS: Of 150 patients, 89 (59.3%) had TAV and 61 (40.7%) BAV. AR ≥ moderate was found in 66 patients with TAV (74.2%) and 49 with BAV (80.3%). At discharge, 74 TAV-patients had ≤ mild AR (84.4%), 11 (12.4%) moderate. 57 patients (93.4%) with BAV had ≤ mild AR, 1 (1.6%) moderate and 2 (3.3%) severe. Mean follow-up was 4.4±2.7 years with ≤ mild AR in 56 TAV patients (73.7%) and moderate in 18 (20.2%). In patients with BAV, 43 (76.8%) had ≤ mild AR and 4 (6.6%) moderate. Survival in patients with TAV was significantly decreased compared to BAV (P=0.033), but reoperation-rates did not differ significantly (P=0.651). CONCLUSIONS: AV-repair is a safe and feasible option in patients with AR and can achieve similar results in patients with TAV and BAV. The complexity of the repair technique predicts repair failure.

In vitro comparison of everting vs. non-everting suture techniques for the implantation of a supra-annular biological heart valve.

BACKGROUND: The aim of this study was to evaluate the hemodynamic effect of different suturing techniques for aortic valve replacement (AVR) in vitro. Whether or not the applied suturing technique impacts the outflow tract diameter by narrowing the annulus diameter was examined. METHODS: The commonly applied non-everting pledget forced suture technique (NE, n=13) was compared with an everting pledget forced suture (ET, n=13) for AVR using the 25 mm St. Jude Trifecta aortic valve. Hemodynamic parameters were obtained in a pulsatile flow simulator. A high speed camera captured the visual aspects of the suturing technique. RESULTS: Despite some kind of left ventricular outflow narrowing due to protruding pledgets using the NE suture technique, mean pressure gradients of both techniques were nearly similar (NE 5.88±2.7 mmHg, ET 5.23±1.31 mmHg, P=0.44). Closing volume (NE 3.16±0.48 mL; ET 3.51±0.68 mL; P=0.14) and the leakage volume (NE: 8.09±2.53 mL; ET: 8.35±3.65 mL; P=0.83) also showed no differences. CONCLUSIONS: AVR using either suturing techniques leads to a similar hemodynamic performance in vitro. The impact of the suturing technique may be higher in a smaller annulus. Therefore, further studies using smaller prostheses are necessary.

Histological examination of explanted tissue-engineered bovine pericardium following heart valve repair.

OBJECTIVES: Our goal was to present histopathological findings of human explants of a tissue-engineered bovine pericardium CardioCel (Admedus Regen Pty Ltd, Malaga, WA, Australia) used for heart valve repair in patients with congenital and acquired heart valve disease. METHODS: Sixty patients underwent heart valve repair from May 2014 to November 2018 using CardioCel as a substitute for valve tissue. We identified 9 cases in which the CardioCel patch was explanted following valve repair and available for histomorphological analyses. CardioCel explants were evaluated histologically using haematoxylin and oeosin, Elastica van Gieson and immunohistochemical stains. RESULTS: The indications for explantation were related to the CardioCel patch in 6 patients. Median time between the implantation and explantation was 242 (range 3-1247) days. We demonstrated a characteristic remodelling pattern with superficial coating of the tissue-engineered bovine pericardium by granulation tissue composed of histiocytes, few lymphocytes and fibrin. We had 2 cases with a multifocal nodular disruption, fragmentation and sclerosis of the decellularized collagen matrix with focal calcification after 795 and 1247 days in situ. CONCLUSIONS: Our data suggest that the tissue-engineered CardioCel patch is initially tolerated in the valvular position in the majority of patients. However, we also experienced graft failures that showed degeneration with fragmentation of the collagen matrix and even 2 cases with focal calcification evident from the histopathological analysis. Further analyses of mid- and long-term performance are mandatory.

Initial Experience With a New Mitral Ring Designed to Simplify Length Determination of Neochords.

BACKGROUND: Artificial chord implantation has become one of the most applied techniques for mitral valve repair (MVR). Many techniques have been described, with the goal of optimizing neochord implantation. A new annuloplasty device designed to simplify the determination of the appropriate neochord length has been recently introduced. We describe our initial experience with this new device. METHODS: The semirigid device is equipped with removable loops on the posterior aspect of the ring. Neochords are tied to the loops, which are subsequently removed. The device was implanted in 47 symptomatic patients from January 2015 to August 2016 through a median sternotomy in 33 patients (70.2%) and a right anterolateral minithoracotomy in 14 (29.8%). The cause of mitral valve insufficiency was degenerative in all patients, and most patients presented with isolated prolapse of the posterior leaflet. Before and after cardiopulmonary bypass, all patients underwent evaluation with transesophageal echocardiography, and transthoracic echocardiography was performed at discharge. RESULTS: A median of 2 neochords were implanted (minimum, 1; maximum, 6). Mean cardiopulmonary bypass time and aortic cross-clamp times were 141.7 ± 32.3 and 104.8 ± 28.5 minutes for combined and 133 ± 53.9 and 98.3 ± 41.6 minutes for isolated MVR. At discharge, echocardiography revealed no or only mild mitral insufficiency in 45 patients (mean gradient, 2.9 ± 1.3 mm Hg). CONCLUSIONS: This new annuloplasty ring facilitated determination of appropriate neochord length and was used to successfully treat different degenerative pathologies affecting both leaflets. This new device simplified length determination of the neochords.

Left ventricular assist devices-current state and perspectives.

Mechanical circulatory support devices have become an important treatment tool for severe acute and chronic heart failure, since heart transplantation cannot meet the demands because of a lack of available donor organs. Since implantation of the first ventricular assist device a constant development of the suitability of these devices has been made. This review will introduce different generations of left ventricular assist devices (LVAD) and elaborate on clinical indications, risk stratification and current literature.

Early haemodynamic performance of a latest generation supra-annular aortic bioprosthesis: experience from a large single-centre series.

OBJECTIVES: The St Jude Medical (SJM) Trifecta bioprosthesis is a recently introduced stented trileaflet pericardial valve designed for supra-annular replacement of the aortic valve (AVR). We sought to evaluate the short-term clinical outcome and haemodynamic performance of the Trifecta valve after AVR. METHODS: A total of 837 patients with severe symptomatic aortic valve stenosis or regurgitation underwent AVR with the SJM Trifecta aortic valve prosthesis between January 2009 and March 2013. All intra- and postoperative data were collected prospectively. At discharge, transthoracic echocardiography was performed. A complete set of echocardiographic data was available in 723 patients. RESULTS: Adjusted mean systolic pressure gradients (MPGs) for valve sizes 19 (n = 37/4.4%), 21 (n = 192/22.9%), 23 (n = 263/31.4%), 25 (n = 202/24.1%), 27 (n = 100/11.9%) and 29 mm (n = 42/5.0%) were 8.6 ± 1.1, 8.7 ± 0.4, 7.2 ± 0.3, 6.2 ± 0.3, 5.6 ± 0.3 and 3.9 ± 0.4 mmHg, respectively. Mean effective orifice area (EOA) for valve sizes 19, 21, 23, 25, 27 and 29 mm were 1.5 ± 0.09, 1.6 ± 0.04, 1.9 ± 0.03, 2.0 ± 0.03, 2.2 ± 0.05 and 2.7 ± 0.01 cm(2), respectively. No patient-prosthesis mismatch (PPM) was seen in 71.3% of patients (EOAI >0.85 cm(2)/m(2)). Moderate mismatch (EOAI 0.65-0.85 cm(2)/m(2)) was observed in 23.9% of patients, whereas severe PPM (EOAI <0.65 cm(2)/m(2)) occurred in 4.4% of patients. No malfunction of the prosthesis, endocarditis, valve thrombosis or relevant aortic regurgitation necessitating surgical revision was observed until discharge. CONCLUSIONS: The SJM Trifecta valve reveals an excellent early haemodynamic performance with low residual MPGs and a low incidence of PPM. Studies with longitudinal clinical and echocardiographic assessments with longer term follow-up evaluation including a comparison with other contemporary bioprostheses are needed.

Cardiopulmonary resuscitation using electrically driven devices: a review.

In the treatment of sudden cardiac arrest (SCA) immediate resuscitation with chest compressions and ventilation is crucial for survival. As manual resuscitation is associated with several drawbacks, mechanical resuscitation devices have been developed to support resuscitation teams. These devices are able to achieve better perfusion of heart and brain in laboratory settings, but real world experience showed no significant improved survival in comparison to manual resuscitation. This review will focus on two mechanical resuscitation devices, the Lund University Cardiac Assist System (LUCAS) and AutoPulse devices and the actual literature available. In conclusion, the general use of mechanical resuscitation devices cannot be recommended at the moment.

Influence of inspiration to expiration ratio on cyclic recruitment and derecruitment of atelectasis in a saline lavage model of acute respiratory distress syndrome.

OBJECTIVE: Cyclic recruitment and derecruitment of atelectasis can occur during mechanical ventilation, especially in injured lungs. Experimentally, cyclic recruitment and derecruitment can be quantified by respiration-dependent changes in PaO2 (ΔPaO2), reflecting the varying intrapulmonary shunt fraction within the respiratory cycle. This study investigated the effect of inspiration to expiration ratio upon ΔPaO2 and Horowitz index. DESIGN: Prospective randomized study. SETTING: Laboratory investigation. SUBJECTS: Piglets, average weight 30 ± 2 kg. INTERVENTIONS: At respiratory rate 6 breaths/min, end-inspiratory pressure (Pendinsp) 40 cm H2O, positive end-expiratory pressure 5 cm H2O, and FIO2 1.0, measurements were performed at randomly set inspiration to expiration ratios during baseline healthy and mild surfactant depletion injury. Lung damage was titrated by repetitive surfactant washout to induce maximal cyclic recruitment and derecruitment as measured by multifrequency phase fluorimetry. Regional ventilation distribution was evaluated by electrical impedance tomography. Step changes in airway pressure from 5 to 40 cm H2O and vice versa were performed after lavage to calculate PO2-based recruitment and derecruitment time constants (TAU). MEASUREMENTS AND MAIN RESULTS: In baseline healthy, cyclic recruitment and derecruitment could not be provoked, whereas in model acute respiratory distress syndrome, the highest ΔPaO2 were routinely detected at an inspiration to expiration ratio of 1:4 (range, 52-277 torr [6.9-36.9 kPa]). Shorter expiration time reduced cyclic recruitment and derecruitment significantly (158 ± 85 torr [21.1 ± 11.3 kPa] [inspiration to expiration ratio, 1:4]; 25 ± 12 torr [3.3 ± 1.6 kPa] [inspiration to expiration ratio, 4:1]; p < 0.0001), whereas the PaO2/FIO2 ratio increased (267 ± 50 [inspiration to expiration ratio, 1:4]; 424 ± 53 [inspiration to expiration ratio, 4:1]; p < 0.0001). Correspondingly, regional ventilation redistributed toward dependent lung regions (p < 0.0001). Recruitment was much faster (TAU: fast 1.6 s [78%]; slow 9.2 s) than derecruitment (TAU: fast 3.1 s [87%]; slow 17.7 s) (p = 0.0078). CONCLUSIONS: Inverse ratio ventilation minimizes cyclic recruitment and derecruitment of atelectasis in an experimental model of surfactant-depleted pigs. Time constants for recruitment and derecruitment, and regional ventilation distribution, reflect these findings and highlight the time dependency of cyclic recruitment and derecruitment.

Apolipoprotein E genotype, TNF-α 308G/A and risk for cardiac surgery associated-acute kidney injury in Caucasians.

OBJECTIVES: Acute kidney injury following cardiac surgery depicts a severe clinical problem that is strongly associated with adverse short- and long-term outcome. We analyzed two common genetic polymorphisms that have previously been linked to renal failure and inflammation, and have been supposed to be associated with cardiac surgery associated-acute kidney injury (CSA-AKI). METHODS: A total of 1415 consecutive patients who underwent elective cardiac surgery with CPB at our institution were prospectively enrolled. Patients were genotyped for Apolipoprotein E (ApoE E2,E3,E4) (rs429358 and rs7412) and TNF-α-308 G > A (rs1800629). RESULTS: Demographic characteristics and procedural data revealed no significant differences between genotypes. No association between ApoE (E2,E3,E4) and TNF-α-308 G > A genotypes and the RIFLE criteria could be detected. Several multiple linear regression analyses for postoperative creatinine increase revealed highly significant associations for aortic cross clamp time (p < 0.001), CPB-time (p < 0.001), norepinephrine (p < 0.001), left ventricular function (p = 0.004) and blood transfusion (p < 0.001). No associations were found for ApoE (E2,E3,E4) and TNF-α-308 G > A genotypes or baseline creatinine. When the sample size is 1415, the multiple linear regression test of R(2 )= 0 for seven covariates assuming normal distribution will have at least 99% power with significance level 0.05 to detect an R(2) of 0.108 or 0.107 as observed in the data. CONCLUSIONS: ApoE (E2,E3,E4) polymorphism and the TNF-α-308 G > A polymorphism are not associated with renal injury after CPB.