Unilateral acute lung injury in pig: a promising animal model.

BACKGROUND: Acute lung injury (ALI) occurs in 23% unilateral. Models of unilateral ALI were developed and used previously without clearly demonstrating the strictly unilateral nature and severity of lung injury by the key parameters characterizing ALI as defined by the American Thoracic Society (ATS). Thus, the use of unilateral ALI remained rare despite the innovative approach. Therefore, we developed a unilateral model of ALI and focused on the crucial parameters characterizing ALI. This model can serve for direct comparisons between the injured and intact lungs within single animals, thus, reducing the number of animals required for valid experimental conclusions. METHODS: We established the model in nine pigs, followed by an evaluation of key parameters in six pigs (main study). Pigs were ventilated using an adapted left double-lumen tube for lung separation and two ventilators. ALI was induced in the left lung with cyclic rinsing (NaCl 0.9% + Triton® X-100), after which pigs were ventilated for different time spans to test for the timing of ALI onset. Ventilatory and metabolic parameters were evaluated, and bronchoalveolar lavage (BAL) was performed for measurements of inflammatory mediators. Finally, histopathological specimens were collected and examined in respect of characteristics defining the lung injury score (LIS) as suggested by the ATS. RESULTS: After adjustments of the model (n = 9) we were able to induce strictly left unilateral ALI in all six pigs of the evaluation study. The median lung injury score was 0.72 (IQR 0.62-0.79) in the left lung vs 0.14 (IQR 0.14-0.16; p < 0.05) in the right lung, confirming unilateral ALI. A significant and sustained drop in pulmonary compliance (Cdyn) of the left lung occurred immediately, whereas Cdyn of the right lung remained unchanged (p < 0.05). BAL fluid concentrations of interleukin-6 and -8 were increased in both lungs. CONCLUSIONS: We established a model of unilateral ALI in pigs, confirmed by histopathology, and typical changes in respiratory mechanics and an inflammatory response. This thoroughly evaluated model could serve as a basis for future studies and for comparing pathophysiological and pharmacological changes in the uninjured and injured lung within the same animal.

Percutaneous mechanical circulatory support from the collaborative multicenter Mechanical Unusual Support in TAVI (MUST) Registry.

OBJECTIVES: To evaluate the use and outcomes of percutaneous mechanical circulatory support (pMCS) utilized during transcatheter aortic valve implantation (TAVI) from high-volume centers. METHODS AND RESULTS: Our international multicenter registry including 13 high-volume TAVI centers with 87 patients (76.5 ± 11.8 years, 63.2% men) who underwent TAVI for severe aortic stenosis and required pMCS (75.9% VA-ECMO, 19.5% Impella CP, 4.6% TandemHeart) during the procedure (prior to TAVI 39.1%, emergent rescue 50.6%, following TAVI 10.3%). The procedures were considered high-risk, with 50.6% having severe left ventricular dysfunction, 24.1% biventricular dysfunction, and 32.2% severe pulmonary hypertension. In-hospital and 1-year mortality were 27.5% and 49.4%, respectively. Patients with prophylactic hemodynamic support had lower periprocedural mortality compared to patients with rescue insertion of pMCS (log rank = 0.013) and patients who did not undergo cardiopulmonary resuscitation during the TAVI procedure had better short and long term survival (log rank <0.001 and 0.015, respectively). CONCLUSIONS: Given the overall survival rate and low frequency of pMCS-related complications, our study results support the use of pMCS prophylactically or during the course of TAVI (bailout) in order to improve clinical outcomes in high-risk procedures or in case of acute life-threatening hemodynamic collapse.

Early Antibiotic Prophylaxis Prior to Bypass Surgery Improves Tissue Penetration.

BACKGROUND: We previously identified preparation of the internal mammary artery as a risk factor significantly impairing antibiotic tissue penetration into the presternal subcutaneous tissue. We, therefore, adapted our dosing schema regarding preoperative timing to overcome this risk factor. METHODS: Eight patients who underwent coronary artery bypass grafting with a left internal mammary artery and vein grafts were included in this clinical trial. Cefazolin (4 g) was administered twice (3 hours and 1 hour) prior to skin incision and once during skin closure (2 g). Antibiotic concentrations were measured with subcutaneous microdialysis probes on both sternal sides. Results were directly compared with the previously published patient cohort receiving the standard schema (4 g cefazolin prior to skin incision and 2 g during closure). RESULTS: All patients (7 male, 1 female, 69 ± 7 years, 26.3 ± 3.9 kg/m2) survived the perioperative period. Mean area under the curve on the right and left sternal side was 117.0 ± 92.5 µg/mL and 114.5 ± 83.2 µg/mL, respectively (p = 0.95). This was well above the previously measured mean peak tissue concentrations without early preoperative antibiotic administration on the side of mammary artery harvesting (52.4 ± 48.5 µg/mL vs. 13.1 ± 5.8 µg/mL; p = 0.039). The %fT > minimal inhibitory concentration (MIC) for Staphylococcus epidermidis and Staphylococcus aureus during the first 10 hours in presternal tissue was ≥ 70% but did not differ compared with standard schema. CONCLUSIONS: Early, additional preoperative administration of cefazolin was able to significantly increase peak tissue concentrations during surgery compared with the standard protocol. No difference, however, could be achieved in the percentage of time during which the concentration exceeded the MIC.

Pushing boundaries in cardiac surgery: minimally invasive mitral valve repair combined with tricuspid valve repair and/or other concomitant procedures.

Introduction: Minimally invasive mitral valve repair/replacement has emerged as a widely accepted surgical approach for managing mitral valve disorders. Continuous technological progress has contributed to the refinement of this procedure, leading to improved safety, decreased surgical trauma, and faster recovery times. Despite these advancements, there remains a scarcity of data concerning minimally invasive complex mitral valve repair surgeries when combined with additional procedures. Methods: Between November 2008 and December 2022, 153 patients underwent an operation using a minimally invasive technique. All patients underwent mitral valve surgery for severe mitral valve insufficiency/stenosis in combination with at least one additional procedure for tricuspid valve repair (n = 52, 34%), patent foramen ovale or atrial septal defect closure (n = 34, 22.2%), left atrial appendage occlusion (n = 25, 16.3%), or electrophysiological procedure (n = 101, 66.0%). Two concomitant procedures were conducted in 98 patients (64.1%), three concomitant procedures in 49 patients (32%), and four concomitant procedures in 6 patients (3.9%). Results: Surgical success was achieved in 99.3% of the patients (n = 152), one patient required a revision of the mitral valve repair on the first postoperative day due to systolic anterior motion phenomenon. Mitral valve repair was performed in 136 patients (88.9%), while 15 patients (9.8%) received a mitral valve replacement as per a preoperative decision due to severe mitral valve stenosis, and two patients (1.3%) underwent other mitral valve procedures. Therapeutic success in treating atrial fibrillation was achieved in 86 patients (85.1%) of the 101 who received an additional maze-procedure. The 30-day mortality rate was 0.7%, with one patient succumbing to respiratory failure. Neurological complications occurred in 7 patients (4.6%). Freedom from reoperation was calculated as 98% at 5-year follow-up and 96.5% at 10-year follow-up. Conclusion: Minimally invasive mitral valve surgery, even when performed alongside concomitant procedures, stands out as a reproducible and safe technique with outstanding outcomes. It is imperative to advance towards the next frontier in minimally invasive surgery, encouraging experienced surgeons to undertake more complex procedures using minimally invasive approaches. These results help envision extending the boundaries of minimally invasive surgery by performing complex mitral valve procedures and associated interventions entirely through endoscopic means in suitable patients.

Surgical Transmitral Thrombectomy to Prevent Recurrent Stroke in Acute Myocardial Infarction.

Left ventricular (LV)-thrombi occur in up to 14 % of patients with acute myocardial infarction (AMI) in the era of primary percutaneous coronary intervention. For these patients, anticoagulant therapy (AC) is recommended by AMI-guidelines. When, despite AC, LV-thrombi lead to embolism, surgical thrombectomy is an option, which is not mentioned or not recommended in AMI-guidelines. We report a 46-year old female patient with AMI. An 80 % stenosis of the proximal left anterior descending coronary artery was treated by a drug-eluting stent. Thrombi within the akinetic LV-apex became mobile despite AC and dual antiplatelet therapy, and a cerebellar stroke occurred. By a transmitral surgical approach with endoscopic assistance the thrombi were completely removed. Postoperative course and 12-months follow-up were uneventful. LV-thrombi should be observed carefully regarding changes in morphology. Surgical thrombectomy of LV-thrombi is a rare treatment option to prevent imminent embolism. Benefits versus risks of surgical removal of LV-thrombi need to be carefully weighted.

Left atrial size predicts outcome in severe but asymptomatic mitral regurgitation.

Patients with severe asymptomatic primary mitral regurgitation (MR) can be safely managed with an active surveillance strategy. Left atrial (LA) size is affected by MR severity, left ventricular function and is also associated with the risk of atrial fibrillation and may be an integrative parameter for risk stratification. The present study sought to determine the predictive value of LA size in a large series of asymptomatic patients with severe MR. 280 consecutive patients (88 female, median age 58 years) with severe primary MR and no guideline-based indications for surgery were included in a follow-up program until criteria for mitral surgery were reached. Event-free survival was determined and potential predictors of outcome were assessed. Survival free of any indication for surgery was 78% at 2 years, 52% at 6 years, 35% at 10 years and 19% at 15 years, respectively. Left atrial (LA) diameter was the strongest independent echocardiographic predictor of event-free survival with incremental predictive value for the thresholds of 50, 60 and 70 mm, respectively. In a multivariable analysis that encompassed age at baseline, previous history of atrial fibrillation, left ventricular end systolic diameter), LA diameter, sPAP > 50 mmHg and year of inclusion, LA diameter was the strongest independent echocardiographic predictor of event-free survival (adjusted HR = 1.039, p < 0.001). LA size is a simple and reproducible predictor of outcome in asymptomatic severe primary MR. In particular, it may help to identify patients who may benefit from early elective valve surgery in heart valve centers of excellence.

Open Transcatheter Mitral Valve Implantation Into the Native Mitral Valve for Inoperable "Big MAC".

Because of the growing population of older adult patients, the prevalence of severe mitral annulus calcification ("big MAC") is increasing. The surgical techniques used to treat big MACs are technically demanding; despite the technical aspect, up to one-third of patients are considered too high risk for conventional surgery but are candidates for the coulisse technique, which is a procedure that implants a transcatheter valve into a native mitral annulus. The anterior leaflet is unfolded, thus reducing the risk of obstructing the left ventricular outflow tract and for paravalvular leak and avoiding valve migration. Preoperative planning, based on a computed tomography scan, is mandatory.

2020 update of the Austrian Society of Cardiology (ÖKG) and the Austrian Society of Cardiac Surgery (ÖGHTG) on the position statement of the ÖKG and ÖGHTG for transcatheter aortic valve implantation 2011.

This position statement is an update to the 2011 consensus statement of the Austrian Society of Cardiology (ÖKG) and the Austrian Society of Cardiac Surgery (ÖGTHG) for transfemoral transcatheter aortic valve implantation.Due to a number of recently published studies, broadening of indications and recommendations of medical societies and our own national developments, the ÖKG and the ÖGHTG wish to combine the 2017 ESC/EACTS guidelines for the management of valvular heart disease with a national position paper and to focus on certain details for the application in Austria. Thus, this position statement serves as a supplement and further interpretation of the international guidelines.

Concomitant Transapical Transcatheter Aortic Valve Implantation and Transapical Mitral Valve Repair With NeoChord Implantation.

One-third of the patients with severe symptomatic aortic valve stenosis (sAS) present with hemodynamic relevant mitral valve insufficiency (rMI). In patients who undergo conventional surgery, the rMI never would be left untreated; however, in cases of transcatheter aortic valve implantation (TAVI), the impact of rMI is often overlooked and left untreated. The combination of transapical TAVI (TA-TAVI) and NeoChord implantation represents a novel, promising therapeutic option for high-risk-surgery patients with sAS and rMI due to a prolapsed or flailed leaflet. This case report describes 2 patients (1 male, 1 female; mean age 82 years) who underwent TA-TAVI and concomitant NeoChord implantation at our institute. Both presented with sAS and rMI due to a prolapse of the P2 segment of the mitral valve. At first, the TA-TAVI was implanted under angio-guidance, followed by three-dimensional echo-guided implantation of the NeoChords, through the same approach, which was slightly posterior and lateral to the apex. TA-TAVI using an Edwards Sapien 3 (26 mm, n = 1 and 29 mm, n = 1) and NeoChord implantation (2 in the first and 3 in the second patient) was successful in both cases. Post-intervention discharge echo indicated no paravalvular or central insufficiency after the procedure and only a trace of mitral valve insufficiency. TA-TAVI and concomitant NeoChord implantation is a feasible and promising treatment option for high-risk patients with rMI. Despite its technical demands, in experienced hands, it is a safe procedure for those not well suited for surgical intervention.

Prognostic Value of Right Ventricular Dysfunction and Tricuspid Regurgitation in Patients with Severe Low-Flow Low-Gradient Aortic Stenosis.

Long and mid-term data in Low-Flow Low-Gradient Aortic Stenosis (LFLG-AS) are scarce. The present study sought to identify predictors of outcome in a sizeable cohort of patients with LFLG-AS. 76 consecutive patients with LFLG-AS (defined by a mean gradient <40 mmHg, an aortic valve area ≤1 cm2 and an ejection fraction ≤50%) were prospectively enrolled and followed at regular intervals. Events defined as aortic valve replacement (AVR) and death were assessed and overall survival was determined. 44 patients underwent AVR (10 transcatheter and 34 surgical) whilst intervention was not performed in 32 patients, including 9 patients that died during a median waiting time of 4 months. Survival was significantly better after AVR with survival rates of 91.8% (CI 71.1-97.9%), 83.0% (CI 60.7-93.3%) and 56.3% (CI 32.1-74.8%) at 1,2 and 5 years as compared to 84.3% (CI 66.2-93.1%), 52.9% (CI 33.7-69.0%) and 30.3% (CI 14.6-47.5%), respectively, for patients managed conservatively (p = 0.017). The presence of right ventricular dysfunction (HR 3.47 [1.70-7.09]) and significant tricuspid regurgitation (TR) (HR 2.23 [1.13-4.39]) independently predicted overall mortality while the presence of significant TR (HR 3.40[1.38-8.35]) and higher aortic jet velocity (HR 0.91[0.82-1.00]) were independent predictors of mortality and survival after AVR. AVR is associated with improved long-term survival in patients with LFLG-AS. Treatment delays are associated with excessive mortality, warranting urgent treatment in eligible patients. Right ventricular involvement characterized by the presence of TR and/or right ventricular dysfunction, identifies patients at high risk of mortality under both conservative management and after AVR.

The impact of perioperative atelectasis on antibiotic penetration into lung tissue: an in vivo microdialysis study.

OBJECTIVE: Postoperative pneumonia is a potentially devastating complication associated with high mortality in intensive care unit (ICU)-patients. One of the major predisposing factors is the perioperative occurrence of atelectatic formations in non-dependent lung areas. Perioperative ventilation/perfusion mismatch due to atelectasis may influence antibiotic distribution to lung tissue, hence increasing the risk of postoperative pneumonia. We evaluated whether differences in ventilation/perfusion mismatch can influence antibiotic distribution into lung tissue by means of in vivo microdialysis, comparing patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) (atelectasis model), with patients operated with the off-pump coronary artery bypass grafting (OPCAB)-technique. PATIENTS AND METHODS: We compared five patients operated with CPB (CPB-group) and five patients undergoing CABG with OPCAB-technique (OPCAB-group). Levofloxacin (500 mg) was administered intravenously, after surgery, in the ICU. Time versus concentration profiles of levofloxacin in lung tissue and plasma were measured at regular time-intervals. RESULTS: In the OPCAB-group, the median of the maximum concentration of levofloxacin in lung tissue (4.1 microg ml(-1) +/- 7, range 3.7-11.8 microg ml(-1)) was significantly higher compared with the CPB-group (2.5 microg ml(-1) +/- 0.3, range 2.0-2.9 microg ml(-1)) (P = 0.046). Median levofloxacin tissue/plasma area under the concentration curve (AUC) ratio in lung tissue was 0.3 +/- 0.2 (range 0.1-0.7) in the CPB-group versus 0.7 +/- 1.6 (range 0.4-0.8) in the OPCAB-group (P = 0.015). CONCLUSIONS: Data indicate that postoperative interstitial antibiotic concentration is influenced by perioperative atelectasis formation. Our findings suggest the re-evaluation of clinical dosing schemas of antibiotic therapy in a variety of diseases associated with atelectasis formation.

The "Paper Roll": A Simple but Useful Tool for Minimal Invasive Mitral Valve Repair Surgery.

During minimal invasive mitral valve repair, excessive valve tissue, as in myxomatous or Barlow disease, might be cumbersome to analyze and treat the subvalvular mitral valve apparatus. We developed a new, adaptive, flexible, and easy-to-use technique for better visualization of the subvalvular apparatus. After visualization of the mitral valve, a simple sterile paper ruler was curled up to a roll 1 cm in diameter and inserted through the mitral valve. By means of two endo forceps, the paper roll was uncurled to the desired diameter, thus pushing the valve leaflets away, allowing for a direct view onto the subvalvular apparatus. This technique was successfully used in 34 consecutive patients (mean ± SD age = 57.2 ± 11.5 years; 22 male). The calculated risk score for additive EuroScore, logistic EuroScore, and EuroScore II was 4 ± 2, 3.2 ± 2.1, and 2.5 ± 5.4, respectively. No patient died within the first 30 days. All patients presented mitral valve insufficiency grade 0 to 1 postoperatively. Artificial chords were implanted in all patients (3.6 ± 1.8 chords per patient). This simple, adaptive, and cheap technique facilitates the approach to the subvalvular apparatus, especially in patients with myxomatous or Barlow disease. The ease of use allows for prompt approach to the papillary muscles and quick removal.

Institutional experience with extracorporeal membrane oxygenation in lung transplantation.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is currently accepted in lung transplantation either to bridge patients to transplantation or to treat postoperatively arising severe primary graft failure. Based on promising initial experiences we have since 2001 implemented ECMO as the standard of intraoperative extracorporeal support in lung transplantation (LuTX) patients with haemodynamic or respiratory instability with the potential to prolong ECMO support into the perioperative period. The aim of this paper is to summarise our total experience with the use of ECMO in LuTX. METHODS: We retrospectively reviewed all 306 patients undergoing primary lung transplantation from 1/2001 to 1/2006 with regard to the different forms of ECMO use. Results of all patients requiring ECMO were compared to those without ECMO during the observation period. RESULTS: ECMO was used in 147 patients in total. Two patients were bridged to transplantation. A total of 130 patients received intraoperative ECMO support. In 51 of these patients ECMO was prolonged into the perioperative period. Five of these patients required ECMO support again in the postoperative period due to graft dysfunction. Contrary cardiopulmonary bypass was used in 27 patients mainly with concomitant cardiac defects. Eleven of these patients needed therapeutic ECMO in the further course. A total of 149 patients without relevant risk factors were transplanted without any intraoperative extracorporeal support. Six of these patients required ECMO support in the postoperative period for treatment of primary graft dysfunction. Overall 3-month, 1-year and 3-year survival rates were 88.6%, 82.1% and 74.63%. The mentioned survival rates were 85.4%, 74.2% and 67.6% in the intraoperative+/-prolonged ECMO group; 93.5%, 91.9% and 86.5% in the no support group and 74.0%, 65.9% and 57.7% in the CPB group. CONCLUSION: ECMO is a valuable tool in lung transplantation providing the potential to bridge patients to transplantation, to replace CPB with at least equal results and to overcome severe postoperative complications. Favourable survival rates can be achieved despite the fact that ECMO is used in the more complex patient population undergoing lung transplantation as well as to overcome already established severe complications.

Five-year haemodynamic outcomes of the first-generation SAPIEN balloon-expandable transcatheter heart valve.

AIMS: Transcatheter aortic valve implantation (TAVI) has gained rapid acceptance for patients with severe aortic stenosis (AS) at high surgical risk for conventional valve replacement. Although TAVI is now a relatively mature technique, limited data about long-term valvular function are available. Our aim was to report the five-year echocardiographic data evaluating valve performance from three early European feasibility studies designed to assess the safety and effectiveness of the first-generation balloon-expandable transcatheter heart valve (SAPIEN THV). METHODS AND RESULTS: A total of 410 patients were enrolled in the following single-arm, non-randomised, prospective multicentre clinical studies: REVIVE II, TRAVERCE and PARTNER EU. Five-year follow-up was completed in 114 surviving patients. Mean patient age was 82.3±5.6 years; 63.4% were female. The mean logistic EuroSCORE was 28.4±13.3%. NYHA Class III/IV was reported in 92.5%. At five years, the mean effective orifice area (EOA) was 1.6±0.6 cm² (n=34) and the mean gradient was 11.7±5.4 mmHg (n=39). In paired patient data, the difference between discharge and five-year EOA was 0.1±0.7 cm² (p=0.3956) and mean gradient was 2.2±5.7 mmHg (p=0.0900). At discharge and five years, respectively, aortic regurgitation (AR) was evaluated as none/trace in 66.6% (n=162/243) and 55.3% (n=19/38), mild in 28.4% (n=69/243) and 39.5% (n=15/38), and moderate in 4.9% (n=12/243) and 5.3% (n=2/38). No severe AR was reported at follow-up. Valve thrombosis was observed in three patients and occurred within one year. No valve-related explants and no case of structural valve deterioration have been reported. CONCLUSIONS: Long-term echocardiographic outcomes in high-risk patients with severe AS suggest stable haemodynamic function of first-generation balloon-expandable SAPIEN THVs at five years, with no worsening of AR severity over time.

Extended donor criteria for lung transplantation--a clinical reality.

OBJECTIVE: Standard lung donor criteria have been established on opinions and individual experiences rather than on existing evidence. Since the scarcity of donor organs is one of the major limitations to lung transplantation, extension of donor lung criteria might considerably increase the donor pool. This study therefore evaluates the outcome, achieved with the use of extended donors versus standard donors and aims to redefine lung donor criteria. METHODS: We performed a retrospective analysis of 98 consecutive primary lung transplantations from 94 donors from 1/2001 to 12/2002. Donors were classified as extended if they fulfilled at least one criteria: age >55 years, PaO(2) at FiO(2)/PEEP 5 <300mmHg, tobacco history >20 pack years, inhalative drug abuse, presence of infiltration on chest X-ray or purulent secretions at bronchoscopy. Recipients were stratified in two groups according to whether they received a 'standard' or 'extended' organ. Postoperative complications, extubation time, ICU and hospital stay and survival were compared. RESULTS: Twenty-three (24.5%) donors were extended. Twenty-six recipients (26.55%) received organs from extended donors. Differences in intubation times (12+/-2 days standard vs. 14+/-5 days extended, P=0.70), ICU stay (16+/-2 days standard vs. 18+/-5 days extended, P=0.74) and hospital stay (38+/-4 days standard vs. 40+/-6 days extended, P=0.71) were not statistically significant. Postoperative bleeding rates were comparable (n=14 standard vs. n=3 extended) as well as bronchial anastomotic complications (n=7 standard vs. n=3 extended). Three months survival was 88.89% in the standard group vs. 92.31% in the extended group. One year survival is comparable as well with 81.94 vs. 84.62%, respectively. CONCLUSIONS: The use of lung donors who fail to meet standard criteria does not impair short and medium term results compared to standard lung donors. The impact on long term development of BOS has yet to be evaluated. The strict application of standard lung donor criteria excludes a considerable number of lungs potentially suitable for transplantation, thus liberalisation of donor criteria might help to overcome donor shortage.

Total endoscopic CABG using robotics on beating heart.

BACKGROUND: The implementation of a total endoscopic coronary surgery on the beating heart with the aid of the Da Vinci surgical system (Intuitive, Sunnyvale, CA) requires a stepwise learning process. After cadaveric training and clinical start of the program in November 2002, we gained experience with arrested heart procedures starting in May 2003. In November 2003, we moved to beating heart surgery. METHODS: From November 2003 to January 2005, 14 patients with coronary artery disease (mean age of 62 +/- 5 years, female to male ratio 2:12) were operated with the intention to perform a beating heart TECAB (totally endoscopic coronary artery bypass grafting) procedure. RESULTS: Total conversion rate was 35% (5/14), due to pleural adhesions in 2 patients, injury of the lung during port placement, inability to occlude the LAD with saddle loops, atherosclerotic diseased mammary artery in 1 patient each. Mean operating time was 298 +/- 110 minutes with a steady decline throughout the study period (first 5 patients: 342 +/- 61 minutes, patients 6 to 9: 337 +/- 87 minutes, last 4 patients: 290 +/- 53 minutes), resulting in a 60 minute shorter operating time. Mean ICU stay was 1.3 days and hospital stay lasted on average 8.4 +/- 2.8 days. CONCLUSION: Total endoscopic bypass surgery on the beating heart with the Da Vinci surgical system can be safely implemented in clinical use. The learning curve results in a constantly decreasing procedure time due to a more effective table team-console surgeon-robotic system interaction and a moderate conversion rate.

Cefazolin and linezolid penetration into sternal cancellous bone during coronary artery bypass grafting.

OBJECTIVES: Deep sternal wound infection is a severe complication after cardiac surgery. Insufficient antibiotic target site concentrations may account for variable success of perioperative prophylaxis. Therefore, we measured perioperative penetration of cefazolin and of linezolid into sternal cancellous bone after sternotomy in coronary artery bypass grafting (CABG) patients by in vivo microdialysis. METHODS: Nine patients underwent CABG using a skeletonized left internal mammary artery. Standard antibiotic prophylaxis consisted of 4 g cefazolin prior to skin incision and additional 2 g during skin closure. In addition, 600 mg of linezolid were administered prior to skin incision and after 12 h for study purposes. Two microdialysis probes were inserted into the sternal cancellous bone (left and right side) after sternotomy. RESULTS: First mean peak cefazolin and linezolid plasma concentrations were 273 ± 92 µg/ml and 22.1 ± 8.9 µg/ml, respectively. Mean peak concentrations of antibiotics in sternal cancellous bone on the left and right sternal side were 112 ± 59 µg/ml and 159 ± 118 µg/ml for cefazolin and 10.9 ± 4.0 µg/ml and 12.6 ± 6.1 µg/ml for linezolid, respectively. Cefazolin exceeded the required tissue concentrations for relevant pathogens by far, but linezolid did not gain effective tissue concentrations in all patients for some relevant pathogens. Mammary artery harvesting had no significant effect on antibiotic tissue penetration. CONCLUSIONS: Direct measurement of antibiotic concentration in sternal cancellous bone with in vivo microdialysis is technically demanding but safe and feasible. We could demonstrate sufficient antibiotic coverage with our standard cefazolin-dosing regimen in the sternal cancellous bone during cardiac surgery. Mammary artery harvesting had no clinically relevant effect on tissue penetration. Linezolid concentrations were not sufficient for some relevant pathogens.

Intrapulmonary shunt after cardiopulmonary bypass: the use of vital capacity maneuvers versus off-pump coronary artery bypass grafting.

OBJECTIVES: It has been proved in human subjects and animals that atelectasis is a major cause of intrapulmonary shunting and hypoxemia after cardiopulmonary bypass. Animal studies suggest that shunting can be prevented entirely by a total vital capacity maneuver performed before termination of bypass. This study aimed to test this theory in human subjects and to evaluate possible advantages of off-pump coronary artery bypass grafting. METHODS: Twenty-four patients scheduled for coronary artery bypass grafting were randomly assigned to receive no total vital capacity maneuver (control group, n = 12) or standard total vital capacity maneuvers (TVCM group, n = 12). Additionally, 12 consecutive patients undergoing off-pump coronary artery bypass grafting (off-pump group) were studied. Systemic and central hemodynamics, the pattern of breathing, and ventilatory mechanics were evaluated after induction of anesthesia, after sternotomy, after cardiopulmonary bypass and skin closure, and 4 hours after extubation. RESULTS: The use of total vital capacity maneuvers reduced (P <.05) intrapulmonary shunting after termination of cardiopulmonary bypass. However, shunting increased (P <.05) in all groups (control group, 8.2% +/- 3.3% vs 25.6% +/- 8.1%; TVCM group, 8.7% +/- 3.4% vs 24.4% +/- 8.5%; and off-pump group, 7.8% +/- 2.8% vs 14.0% +/- 5.3%) after extubation, but the increase was significantly (P <.05) less pronounced in the off-pump group. Furthermore, pulmonary compliance decreased (P <.05) in all groups except the off-pump group after extubation. Duration of hospital and intensive care unit stay was significantly shorter (P <.05) in the off-pump group than in the other groups. CONCLUSION: The development of intrapulmonary shunting and hypoxemia after coronary artery bypass grafting can be substantially reduced by performance of total vital capacity maneuvers while patients are mechanically ventilated. However, off-pump coronary artery bypass surgery is superior in preventing shunting and hypoxemia after bypass grafting in the immediate and early postoperative periods, probably leading to substantially shorter intensive care unit and hospital stays.

Heterotopic tracheal transplantation with omentum wrapping in the abdominal position preserves functional and structural integrity of a human tracheal allograft.

OBJECTIVES: Transplantation of a human trachea has been reported only twice in the literature with limited documentation of the functional and structural properties of the allograft. PATIENTS AND METHODS: A 57-year-old patient with chronic obstructive pulmonary disease with low segment tracheal stenosis was accepted for lung transplantation and 2-stage tracheal allotransplantation. Standard bilateral sequential lung transplantation was performed with the transfer of the donor trachea into the recipient's abdomen, which was wrapped in the greater omentum and sutured into the abdominal wall, similar to a stoma. The patient received immunosuppression consisting of cyclosporine A, mycophenolate mofetil, and cortisone. Sixty days later, the tracheal allograft presented with macroscopically normal appearance with maintained elasticity and rigidity. The patient underwent a cricotracheal resection 6 months after lung transplantation. However, reconstruction with direct end-to-end anastomosis was achievable. The tracheal allograft, therefore not needed for reconstruction, was harvested and underwent complete investigations. RESULTS: Cross-section of the graft revealed a mechanically stable and macroscopically intact trachea. Hematoxylin-eosin staining demonstrated vital cartilage covered by respiratory epithelium. Angiography, followed by corrosion studies and electromicroscopy, demonstrated excellent vascularization of the tracheal wall. CONCLUSION: The patient is alive 31 months posttransplantation and remains in bronchiolitis obliterans syndrome stage 0. Human trachea wrapped in omentum maintains its functional and structural integrity and may be used for 2-stage allotransplantation.

Successful lung volume reduction surgery brings patients into better condition for later lung transplantation.

OBJECTIVES: Lung volume reduction surgery (LVRS) is accepted as a potential alternative therapy to lung transplantation (LTX) for selected patients. However, the possible impact of LVRS on a subsequent LTX has not been clearly elucidated so far. We therefore analyzed the course of 27 patients who underwent LVRS followed by LTX in our institution. METHODS: Twenty-seven patients (11 male, 16 female, mean age 51.9+/-2.2 years) out of 119 patients who underwent LVRS between 1994 and 1999 underwent LTX 29.7+/-3.2 months (range 2-57 months) after LVRS. Based on the postoperative course of FeV1 after LVRS (best value within the first 6 months postoperatively compared with the preoperative value) patients were divided into two groups: Group A (n=11) without any improvement (FeV1 <20% increase), and Group B (n=16) with FeV1 increase > or = 20% after successful LVRS which declined to preoperative values after 8-42 months. Subsequent LTX was performed 22.9+/-5.6 months after LVRS in Group A and 34.3+/-4.9 months after LVRS in Group B (P<0.05). Patients were analyzed according to the course of their functional improvement and of their body mass index (BMI) after LVRS and to survival after LTX, respectively. Values are given as the mean+/-SEM and significance was calculated by the chi(2)-test whereas continuous values were estimated by Student's t-test. RESULTS: Patients in Group A without improvement in FeV1 after LVRS had no increase in BMI as well and this resulted in a high perioperative mortality of 27.3% after LTX. On the contrary, patients in Group B, who had a clear increase of FeV1 after LVRS, experienced a significant increase of BMI of 23.2+/-4.5% as well (P<0.05). This improvement in BMI remained stable despite a later deterioration of FeV1 prior to LTX. After LTX, these patients had a significantly lower perioperative mortality of 6.3% as compared to Group A (P=0.03). CONCLUSIONS: Successful LVRS delays the need for transplantation, improves nutritional status and brings patients into a better pretransplant condition, which results in decreased perioperative mortality at LTX. Patients after failed LVRS, however, should be considered as poor candidates for later transplantation.