Increased Drop in Activity of Alkaline Phosphatase in Plasma from Patients with Endocarditis.

(1) Infective endocarditis is a severe inflammatory disease associated with substantial mortality and morbidity. Alkaline phosphatase (AP) levels have been shown to change significantly during sepsis. Additionally, we previously found that a higher initial AP drop after cardiac surgery is associated with unfavorable outcomes. Therefore, the course of AP after surgery for endocarditis is of special interest. (2) A total of 314 patients with active isolated left-sided infective endocarditis at the Department of Cardiac Surgery (Medical University of Vienna, Vienna, Austria) between 2009 and 2018 were enrolled in this retrospective analysis. Blood samples were analyzed at different time points (baseline, postoperative days 1-7, postoperative days 14 and 30). Patients were categorized according to relative alkaline phosphatase drop (≥30% vs. <30%). (3) A higher rate of postoperative renal replacement therapy with or without prior renal replacement therapy (7.4 vs. 21.8%; p = 0.001 and 6.7 vs. 15.6%; p = 0.015, respectively) and extracorporeal membrane oxygenation (2.2 vs. 19.0%; p = 0.000) was observed after a higher initial alkaline phosphatase drop. Short-term (30-day mortality 3.0 vs. 10.6%; p = 0.010) and long-term mortality (p = 0.008) were significantly impaired after a higher initial alkaline phosphatase drop. (4) The higher initial alkaline phosphatase drop was accompanied by impaired short- and long-term outcomes after cardiac surgery for endocarditis. Future risk assessment scores for cardiac surgery should consider alkaline phosphatase.

Performing central venous catheters in neonates and small infants undergoing cardiac surgery using a wireless transducer for ultrasound guidance: a prospective, observational pilot study.

BACKGROUND: Neonates and small infants with congenital cardiac disease undergoing cardiac surgery represent major challenges facing paediatric anaesthesia and perioperative medicine. AIMS: We here aimed to investigate the success rates in performing ultrasound (US) guided central venous catheter insertion (CVC) in neonates and small infants undergoing cardiac surgery, and to evaluate the practicability and feasibility of thereby using a novel wireless US transducer (WUST). METHODS: Thirty neonates and small infants with a maximum body weight of 10 kg and need for CVC before cardiac surgery were included in this observational trial and were subdivided into two groups according to their weight: < 5 kg and ≥ 5 kg. Cannulation success, failure rate, essential procedure related time periods, and complications were recorded and the clinical utility of the WUST was assessed by a 5-point Likert scale. RESULTS: In total, CVC-insertion was successful in 27 (90%) of the patients and the first attempt was successful in 24 (78%) of patients. Success rates of CVC were 80% < 5 kg and 100% ≥5 kg. Comparing the two groups we found a clear trend towards longer needle insertion time in patients weighing < 5 kg (33 [28-69] vs. 24 [15-37]s, P = .07), whereas, the total time for catheter insertion and the duration of the whole procedure were similar in both groups (199 [167-228] vs. 178 [138-234] and 720[538-818] vs. 660 [562-833]s. In total, we report 3 (10%) cases of local hematoma as procedure-related complications. Assessments of the WUST revealed very good survey results for all parameters of practicability and handling (all ratings between 4.5 and 5.0). CONCLUSION: Although difficulties in CVC-placement seem to relate to vessel size and patient's weight, US guided CVC-insertion represents a valuable, fast, and safe intervention in neonates and small children undergoing cardiac surgery. Using the WUST is feasible for this clinical application and may aid in efforts aiming to optimize perioperative care. TRIAL REGISTRATION: Wireless US-guided CVC placement in infants; Clinicaltrials.gov: NCT04597021 ; Date of Registration: 21October, 2020; retrospectively registered.

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.

Thoracic endovascular repair for acute complicated type B aortic dissections.

OBJECTIVE: This study retrospectively assessed in-hospital mortality and long-term results of emergency thoracic endovascular aortic repair (TEVAR) for patients with life-threatening acute complicated type B aortic dissection (acTBD). METHODS: Between March 2001 and December 2016, there were 55 patients (40 male; median age, 52 ± 13 years) with an acTBD who were treated with TEVAR for malperfusion (58%), aortic rupture (18%), or persistent untreatable pain with true lumen reduction or rapid aortic diameter enlargement (24%) as a sign of disease progression. The patients were categorized according to clinical appearance into two groups: group A, malperfusion, pending rupture, or rupture; and group B, persistent ongoing pain, rapid enlargement of aortic diameter, or significant changes in the true to false lumen ratio. Four patients (7%) had undergone previous aortic surgery. RESULTS: Technical success (coverage of the primary intimal tear) was achieved in 50 patients (91%). The overall in-hospital mortality rate was 9% (n = 5), and there was a statistically significant difference in early mortality between group A and group B (7% vs 2%; P < .02). Causes of in-hospital death were all aorta related, including a rupture during the procedure and on the first postinterventional day in two patients and redissection (ascending aorta, n = 2; descending aorta, n = 1) with a consequent aortic rupture after TEVAR in the remaining three. Permanent neurologic dysfunction occurred in five patients (stroke, n = 2; paraplegia, n = 3). Overall, 19 patients (34%) developed early endoleaks (type IA, n = 5; type IB, n = 11; type II, n = 2; type IB plus type II, n = 1). Therefore, 5 patients needed early (within 30 days) endovascular intervention because of a type IA (n = 2), type IB (n = 3), or type II endoleak (n = 1) and the rapid progression of aortic diameter, persistent signs of ischemia (n = 2), or rupture (n = 1), whereas the remaining 14 patients were treated conservatively and followed up by computed tomography angiography. Seven patients with early endoleaks needed an endovascular intervention (n = 3) or conventional surgery (n = 4) because of aortic progression in the follow-up period (mean interval after procedure, 92 ± 56 months). The actual survival rates were 87%, 85%, and 75% at 1 year, 2 years, and 5 years, respectively, and freedom from aorta-related death was 87%, 87%, and 77% at 1 year, 2 years, and 5 years, respectively. Freedom from reintervention for any cause using a Kaplan-Meier analysis was 70%, 68%, 68%, and 63% at 6 months, 1 year, 2 years, and 5 years, respectively. CONCLUSIONS: TEVAR of acTBD has been proven to be an excellent treatment modality in this cohort of high-risk patients, with promising midterm and long-term results.

Cefuroxime plasma and tissue concentrations in patients undergoing elective cardiac surgery: Continuous vs bolus application. A pilot study.

AIMS: Surgical site infections contribute to morbidity and mortality after surgery. The authors hypothesized that higher antibiotic tissue concentrations can be reached for a prolonged time span by continuous administration of prophylactic cefuroxime compared to bolus administration. METHODS: Twelve patients undergoing elective cardiac surgery were investigated. Group A received 1.5 g cefuroxime as bolus infusions before surgery, and 12 and 24 hours thereafter. In group B, a continuous infusion of 3.0 g cefuroxime was started after a bolus of 1.5 g. Cefuroxim levels were determined in blood and tissue (microdialysis). T-test, Wilcoxon signed rank test and χ2 test were used for statistical analysis. RESULTS: The area under the curve (AUC) of plasma cefuroxime concentrations was greater in group B (399 [333-518]) as compared to group A (257 [177-297] h mg L-1 , [median and interquartile range], P = .026). Furthermore, a significantly longer percentage of time > minimal inhibitory concentrations of 2 mg L-1 (100% vs 50%), 4 mg L-1 (100% vs 42%), 8 mg L-1 (100% vs 17%) and 16 mg L-1 (83% vs 8%) was found for free plasma cefuroxime in group B. In group B, area under the curve in subcutaneous tissue (78 [61-113] h mg L-1 ) and median peak concentration (33 [26-38] mg L-1 ) were markedly higher compared to group A (P = 0.041 and P = .026, respectively). CONCLUSIONS: Higher cefuroxime concentrations were measured in plasma and subcutaneously over a prolonged period of time when cefuroxime was administered continuously. The clinical implication of this finding still has to be elucidated.

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.

Impact of Venoarterial Extracorporeal Membrane Oxygenation on Alkaline Phosphatase Metabolism after Cardiac Surgery.

(1) Alkaline phosphatase (AP) is consumed during cardiopulmonary bypass (CPB). A high AP depletion leads to an impaired outcome after cardiac surgery. However, data is scarce on the postoperative course of AP under venoarterial ECMO (VA-ECMO) support. (2) A total of 239 patients with VA-ECMO support between 2000 and 2019 at the Department of Cardiac Surgery (Vienna General Hospital, Austria) were included in this retrospective analysis. Blood samples were collected at several timepoints (baseline, postoperative day (POD) 1-7, POD 14 and 30). Patients were categorized according to the relative AP drop (<60% vs. ≥60%) and ECMO duration (<5 days vs. ≥5 days). (3) Overall, 44.4% reached the baseline AP values within 5 days-this was only the case for 28.6% with a higher AP drop (compared to 62.7% with a lower drop; p = 0.000). A greater AP drop was associated with a significantly higher need for renal replacement therapy (40.9% vs. 61.9%; p = 0.002) and an impaired 1-year survival (51.4% vs. 66.0%; p = 0.031). (4) CPB exceeds the negative impact of VA-ECMO; still, ECMO seems to delay alkaline phosphatase recovery. A greater initial AP drop bears the risk of higher morbidity and mortality.

Decrease in serum alkaline phosphatase and prognostic relevance in adult cardiopulmonary bypass.

OBJECTIVES: Cardiopulmonary bypass (CPB) induces inflammatory responses, which may lead to the loss of alkaline phosphatase (AP) that is consumed in the process of dephosphorylating detrimental extracellular nucleotides in this proinflammatory state. It has been reported that low postoperative AP levels correlate with increased postoperative support requirement and organ dysfunction after paediatric cardiac surgery. However, little is known about the perioperative development and clinical relevance of AP depletion in adults undergoing CPB. METHODS: A total of 183 patients with a preoperative left ventricular ejection fraction ≤50% undergoing mitral valve surgery ± concomitant related procedures at the Department of Cardiac Surgery, Medical University of Vienna, between 2013 and 2016 were included in this retrospective analysis. Serum AP measurements at baseline and on postoperative days 1-15 were collected. Absolute and relative drop of AP on postoperative day 1 from baseline was correlated with perioperative and early postoperative parameters. Receiver operating characteristics were used to define suitable predictors and cut-offs for postoperative outcome variables. RESULTS: Receiver operating characteristics showed a reduction of >50% of baseline AP to predict in-hospital mortality [area under the curve (AUC) 0.807], prolonged intensive care unit stay (>72 h, AUC 0.707), prolonged mechanical ventilation (>24 h, AUC 0.712) and surgery-related dialysis requirement (AUC 0.736). Patients with a perioperative reduction in circulating AP to levels below 50% of baseline had a significantly decreased survival. Patients with high perioperative AP loss had higher preoperative AP levels (P < 0.001), longer CPB duration (P < 0.001) and higher incidence of extracorporeal membrane oxygenation support (P < 0.001). CONCLUSIONS: Increased perioperative AP loss is associated with adverse early outcome. Prospective trials are needed to determine whether this effect can be counteracted by perioperative AP supplementation.

Influence of vancomycin on renal function in critically ill patients after cardiac surgery: continuous versus intermittent infusion.

BACKGROUND: Vancomycin is frequently used in clinical practice to treat severe wound and systemic infections caused by Gram-positive bacteria after cardiac surgery. The drug is excreted almost entirely by glomerular filtration and might exhibit nephrotoxic side effects. This study compared the nephrotoxic impact of vancomycin during continuous versus intermittent administration. METHODS: The authors analyzed 149 patients admitted to the intensive care unit during a 5-yr period. All patients were treated at the intensive care unit after elective open heart surgery. Thirty patients received a dosage of 1325 +/- 603 mg/d vancomycin (range 300-3400 mg/d) by intermittent infusion, and 119 patients received a mean dosage of 1935 +/- 688 mg/d (range 352-3411 mg/d) by continuous infusion. RESULTS: Nephrotoxicity occurred in 11 patients (36.7%) in the intermittent treatment group and in 33 patients (27.7%) in the continuous treatment group (P = 0.3; 95% CI = 0.283). Continuous veno-venous hemofiltration after vancomycin administration was required for 9 patients (9 of 30; 30%) in the intermittent treatment group and for 28 (28 of 119; 23.5%) in the continuous treatment group (P = 0.053; 95% CI = 0.256). A change of one unit (1 mg/l) in vancomycin serum concentration (DeltaVancoC) induced an average change of 0.04 mg/dl in creatinine (DeltaCrea) in the intermittent treatment group versus 0.006 mg/dl in the continuous treatment group (P < 0.001). CONCLUSIONS: The data show that both the intermittent and also the continuous application modality of vancomycin are associated with deterioration of renal function in critically ill patients after cardiac surgery. However, continuous infusion showed the tendency to be less nephrotoxic than the intermittent infusion of vancomycin.

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.

Direct sternal administration of Vancomycin and Gentamicin during closure prevents wound infection.

OBJECTIVES: Deep sternal wound infection is still a major complication in patients undergoing cardiac surgery. We previously identified mammary artery harvesting as a risk factor for decreased antibiotic tissue penetration. In addition, other risk factors including diabetes may inhibit sufficient tissue penetration of perioperative antibiotic prophylaxis. A novel closure protocol applying 2 topical antibiotics and further recommendations for sternal wiring was introduced at our department to decrease the incidence of sternal wound infections. METHODS: A 12-month period prior to (March 2013-February 2014) and after (July 2014-June 2015) the introduction of a novel sternal closure protocol was studied. All sternal wound infections resulting from an operation during this period were analysed. The closure protocol consisted of the intra-sternal application of vancomycin and the subcutaneous application of gentamicin. Furthermore, we increased the number of sternal wires for more uniform distribution of lateral forces. RESULTS: Patients in both groups were comparable regarding demographic data and risk factors. Fifty-three out of 919 patients operated prior to the protocol change developed an infection (5.8%). The introduction of the novel sternal closure protocol reduced this number to 19 out of 932 patients (2.0%; P < 0.001). A binary regression including common risk factors revealed a strong independent risk reduction by the novel protocol (OR 0.322, P < 0.001). The number of sternal wires was not significant in this analysis. CONCLUSIONS: The topical application of 2 antibiotic agents significantly reduced sternal wound infection. However, the results of this trial should be confirmed in a randomized trial.

Acute Kidney Injury and Outcome After Heart Transplantation: Large Differences in Performance of Scoring Systems.

BACKGROUND: Kidney function is an important aspect for patient outcome after heart transplantation (HTX). Acute kidney injury (AKI) is defined by changes in serum creatinine (SCr) and diuresis with risk/injury/failure/loss/end stage (RIFLE), acute kidney injury network (AKIN), or kidney disease: improving global outcomes (KDIGO) scores. METHODS: We investigated the effect of perioperative AKI on 1-year mortality after HTX over a period of 10 years at a single-center university hospital. Multivariable Cox proportional-hazards regression analyzed the association between 1-year mortality and potential risk factors. Receiver operating curves for 1-year mortality were calculated to determine sensitivity and specificity of scores. RESULTS: Sixty of 346 patients (17%) died within the first year. Acute kidney injury was a predictor of mortality only in the high-risk AKI groups of all scores: Hazard ratios (95% confidence interval) for RIFLE F: 7.164 (3.307-15.523); KDIGO/AKIN stage 3: 3.492 (2.006-6.081). Within each score, we identified patient groups, which had no elevated risk for an adverse outcome despite their allocation to the milder forms of AKI. In multivariable regression analysis, primary graft dysfunction was the predominant perioperative risk factor for 1-year mortality. CONCLUSIONS: In contrast to other patient cohorts, mild forms of perioperative AKI are of subordinate influence on patient outcome in HTX.

Impact of Rabbit Antithymocyte Globulin Dose on Long-term Outcomes in Heart Transplant Patients.

BACKGROUND: Optimal dosing strategies have not been established for rabbit antithymocyte globulin (rATG) after heart transplantation, and there is currently wide variability in rATG regimens with respect to both dose and duration. METHODS: In a retrospective, single-center analysis, 523 patients undergoing heart transplantation during 1996 to 2009 were stratified by cumulative rATG dose: less than 4.5 mg/kg (group A), 4.5 to 7.5 mg/kg (group B) or greater than 7.5 mg/kg (group C). RESULTS: Survival at 1 year after transplantation was 80% in group A, 90% in group B, and 88% in group C (P = 0.062). Incidence of acute rejection per 1000 patient-years was significantly higher in group A (hazards ratio [HR], 54.8; 95% confidence interval [95% CI], 33.9-83.8) compared to groups B (19.6; 95% CI, 11.4-31.4) and C (23.6; 95% CI, 17.5-31.3). Incidence of severe infection 10 years after transplantation was higher in group C (45%) than groups A (37%) or B (23%) (P < 0.001); cytomegalovirus infection rates were 35%, 20% and 23%, respectively (P = 0.009). Multivariable Cox regression showed an HR of 0.51 (95% CI, 0.25-1.02) for acute rejection with group B versus group A, and 0.54 (95% CI, 0.33-0.88; P = 0.013) for severe infection. The rate of malignancy per 1000 patient-years was higher in groups B (13.85) and C (14.95) than group A (7.83). CONCLUSIONS: These retrospective data suggest that a cumulative rATG dose of 4.5 to 7.5 mg/kg may offer a better risk-benefit ratio than lower or higher doses, with acceptable rates of infection and posttransplant malignancy. Prospective trials are needed.

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.

Risk factors of mortality and permanent neurologic injury in patients undergoing ascending aortic and arch repair.

OBJECTIVES: To analyze outcome in elderly patients after surgical repair of the ascending aorta and the aortic arch as compared with their younger counterparts and to determine risk factors of mortality and permanent neurologic injury. Patients and methods Between January 1995 and February 2003, a total of 369 patients underwent ascending aortic and arch repair. Indications for surgical intervention were acute type A dissections in 174 (47%) patients (<75 years, n = 147; > or =75 years, n = 27) and chronic atherosclerotic aneurysms in 195 (53%) patients (<75 years, n = 168; > or =75 years, n = 27). Emergency surgery was performed in 167 (45%) patients; 202 patients (54.7%) underwent surgery requiring deep hypothermic circulatory arrest. Pre- and intraoperative factors were evaluated by means of stepwise logistic regression analysis to determine risk factors of mortality and permanent neurologic injury. RESULTS: Overall in-hospital mortality was 11.6%. In-hospital mortality with regard to indication for surgical intervention was comparable in both age groups (type A dissection: <75 years, 15.6%; > or =75 years, 18.5%; P =.731; chronic atherosclerotic aneurysm: <75 years, 7.7%; > or =75 years, 7.4%; P =.933). Permanent neurologic injury was observed in 5.0%. Permanent neurologic injury with regard to surgical intervention was comparable in both age groups (type A dissection: <75 years, 8.8%; > or =75 years, 3.7%; P =.359; chronic atherosclerotic aneurysm: <75 years, 3.0%; > or =75 years, 3.7%; P =.843). Stepwise logistic regression analysis revealed preoperative hemodynamic instability (odds ratio 4.3; P =.000), duration of cardiopulmonary bypass (odds ratio 2.1; P =.001), and permanent neurologic injury (odds ratio 1.7; P =.033) but not age as independent predictors affecting mortality. Utilization of but not duration of deep hypothermic circulatory arrest was the only independent predictor of permanent neurologic injury (odds ratio 2.8; P =.019). CONCLUSIONS: Age shows a trend toward a higher risk of mortality but does not predict a higher incidence of permanent neurologic injury after ascending aortic and arch repair. As utilization of deep hypothermic circulatory arrest remains the only independent predictor of permanent neurologic injury, alternative approaches to maintain cerebral perfusion during ascending aortic and arch repair are warranted.

A double patch sandwich technique for surgical repair of acute aortic dissection type A.

BACKGROUND: This study compares two groups of patients with acute aortic dissection type A in whom two different techniques of anastomotic reinforcement were used, and evaluates the impact of these two techniques on perioperative blood loss and surgical outcome. METHODS: One hundred eighty-five consecutive patients with acute aortic dissection type A between 1998 and 2002 were grouped according to the technique utilized for reinforcing the aortic anastomotic site. Group A consisted of 21 patients in whom a novel double patch sandwich technique was used, whereas in group B (164 patients) conventional Teflon felt strips served as reinforcement. RESULTS: Preoperative profiles were comparable for both groups. Deep hypothermia and circulatory arrest were used in 180 patients (97%). Retrograde cerebral perfusion and retrograde cardioplegia were used in 70 patients (38%). Hospital mortality for the two groups was 4.7% (1 of 21) and 18% (29 out of 164), p < 0.30, respectively. On average 2 versus 6 U of PRBC (p < 0.21), and 3 versus 5 U of FFP (p < 0.004) were given during operation in groups A and B, respectively, and indicates reduced suture line bleeding in group A. CONCLUSIONS: Modifications in the surgical technique for repair of acute aortic dissection type A, and in anastomotic reinforcement in particular, may lead to substantial reduction of suture line bleeding and diminished blood loss and transfusion requirements, and favorably affects patient outcome. Nevertheless, continued effort is mandatory to further enhance surgical outcome in this patient population.

The incidence of transient neurologic dysfunction after ascending aortic replacement with circulatory arrest.

BACKGROUND: Transient neurologic dysfunction (TND) namely postoperative confusion, delirium, and agitation after aortic operation, particularly after deep hypothermic circulatory arrest (DHCA), remains an underestimated adverse event in the early outcome of these patients. Although no influence on long-term outcome has been reported so far, this entity markedly affects the early outcome and leads to prolonged intensive care unit and hospital stay. METHODS: Between January 1997 and January 2003, 160 consecutive patients (130 type A dissections [81%] and 30 elective atherosclerotic aneurysms [19%]) had surgical repair with DHCA for a thoracic aortic aneurysm limited to the ascending aorta. From those, 40 patients (25%) underwent DHCA alone, whereas in 13 patients (8%) antegrade cerebral perfusion and in 103 patients (64%) retrograde cerebral perfusion was used for further brain protection. RESULTS: The overall incidence of TND was 18% (28 of 160) with a significant association between duration of circulatory arrest and the incidence of TND (13.8% in DHCA < 30 minutes versus 37.9% in DHCA > 40 minutes; p < 0.05). Furthermore the severity of TND was directly associated with the duration of circulatory arrest and age. In contrast, however, the use of retrograde cerebral perfusion had no influence on the incidence of TND, (p < 0.05). Intensive care unit stay as well as hospital stay were prolonged in the patients with TND (intensive care unit 14.3 +/- 14.2 days versus 10.8 +/- 13.7 days, p < 0.05; hospital stay 15.6 +/- 10.1 days versus 11.4 +/- 7.9 days, p < 0.05). CONCLUSIONS: Duration of DHCA, regardless of whether retrograde cerebral perfusion was used, was the most important predictor of the incidence of transient neurologic dysfunction in patients who had replacement of the ascending thoracic aorta. The occurrence of TND leads to impaired functional recovery as well as prolonged intensive care unit and hospital stay.

Combined surgical and endovascular treatment of acute aortic dissection type A: preliminary results.

BACKGROUND: The established treatment modality of acute Stanford type A dissection includes repair of the ascending aorta and various portions of the aortic arch, whereas the descending aorta is left untreated. We report a simultaneous approach of open repair of the ascending aorta with transluminal stent grafting of the descending aorta to minimize the consequences of an untreated descending aorta. METHODS: From April 2001 to February 2002, 8 consecutive patients (3 women [37.5%] and 5 men [62.5%]) with a mean age of 55.7 years (range, 45 to 70 years) were intended to be treated with the combined method of surgical repair of the ascending aorta and transluminal stent grafting into the descending aorta during the period of deep hypothermic circulatory arrest. Circulatory arrest time ranged between 30 and 67 minutes (average, 38.8 minutes). Specially designed Talent stent grafts (32 to 40 mm in diameter, length 13 cm) were inserted under direct vision and deployed with the proximal end at the origin of the left subclavian artery. RESULTS: Intraoperative stent graft placement was successful in 7 patients (87.5%). Because of severe kinking of the distal arch, stent insertion failed in 1 patient (12.5%). One patient with a history of preoperative stroke in the middle cerebral artery died because of intracerebral bleeding on postoperative day 2, resulting in an in-hospital mortality of 12.5%. Mean intensive care unit stay was 6.4 days (range, 2 to 21 days) and overall hospital stay was 18.2 days (range, 7 to 33 days). Completion computed tomographic scans revealed complete thrombosis of the false lumen in 2 patients and partial thrombosis in 4 patients. Follow-up was complete and ranged from 1 to 9 months (mean, 5.4 months). CONCLUSIONS: This preliminary study shows that combined surgical and endovascular treatment of acute type A dissection is feasible, and at least partial thrombosis of the false lumen can be achieved, potentially minimizing the risk of further dilatation or rupture. Additionally, the stent graft expands the otherwise sickle-shaped true lumen, thereby ameliorating distal aortic perfusion. Long-term results are warranted to demonstrate the effectiveness of this new combined treatment modality.