Intraoperative reduction of vasopressors using processed electroencephalographic monitoring in patients undergoing elective cardiac surgery: a randomized clinical trial.

Intraoperative vasopressor and fluid application are common strategies against hypotension. Use of processed electroencephalographic monitoring (pEEG) may reduce vasopressor application, a known risk factor for organ dysfunction, in elective cardiac surgery patients. Randomized single-centre clinical trial at Jena University Hospital. Adult patients operated on cardiopulmonary bypass or off-pump coronary artery bypass grafting were randomised to receive anesthesia with visible or blinded pEEG using Narcotrend™. In blinded-Narcotrend (NT) depth of anesthesia was extrapolated from clinical signs, hemodynamic response and anesthetic concentration, supplemented by target indices between 37 and 64 in the visible-NT group. Intraoperative norepinephrine requirement (primary endpoint), fluid balance, extubation time, delirium occurrence and adverse events were evaluated. Patients of the intent-to-treat population (visible-NT: n = 123, blinded-NT: n = 122) had similar patient and procedural characteristics. Adjusted for type of surgery intraoperative Norepinephrine application was significantly reduced in visible-NT (n = 120, robust mean of cumulative dose 4.71 µg/kg bodyweight) compared to blinded-NT patients (n = 119, 6.14 µg/kg bodyweight) (adjusted robust mean difference 1.71 (95% CI 0.33-3.10) µg/kg bodyweight). Although reduction in patients operated on cardiopulmonary bypass was higher the interaction was not significant in post-hoc subgroup analysis. Intraoperative fluid balance was similar among both groups and strata. Extubation time was non-significantly lower in visible than in blinded-NT group. Overall postoperative delirium risk was 16.4% without differences among the groups. Adverse events-sudden movement/coughing, perspiration or hypertension-occurred more often with visible-NT, while one blinded-NT patient experienced intraoperative awareness. Titration of depth of anesthesia in elective cardiac surgery patients using pEEG allows to reduce application of norepinephrine.

S. aureus endocarditis: Clinical aspects and experimental approaches.

Infective endocarditis (IE) is a life-threatening disease, caused by septic vegetations and inflammatory foci on the surface of the endothelium and the valves. Due to its complex and often indecisive presentation the mortality rate is still about 30%. Most frequently bacterial microorganisms entering the bloodstream are the underlying origin of the intracardiac infection. While the disease was primarily restricted to younger patients suffering from rheumatic heart streptococci infections, new at risk categories for Staphylococcus (S.) aureus infections arose over the last years. Rising patient age, increasing drug resistance, intensive treatment conditions such as renal hemodialysis, immunosuppression and long term indwelling central venous catheters but also the application of modern cardiac device implants and valve prosthesis have led to emerging incidences of S. aureus IE in health care settings and community. The aetiologic change has impact on the pathophysiology of IE, the clinical presentation and the overall patient management. Despite intensive research on appropriate in vitro and in vivo models of IE and gained knowledge about the fundamental mechanisms in the formation of bacterial vegetations and extracardiac complications, improved understanding of relevant bacterial virulence factors and triggered host immune responses is required to help developing novel antipathogenic treatment strategies and pathogen specific diagnostic markers. In this review, we summarize and discuss the two main areas affected by the changing patient demographics and provide first, recent knowledge about the pathogenic strategies of S. aureus in the induction of IE, including available experimental models of IE used to study host-pathogen interactions and diagnostic and therapeutic targets. In a second focus we present diagnostic (imaging) regimens for patients with S. aureus IE according to current guidelines as well as treatment strategies and surgical recommendations.

Impact of perioperative liver dysfunction on in-hospital mortality and long-term survival in infective endocarditis patients.

PURPOSE: Infective endocarditis (IE) is often associated with multiorgan dysfunction and mortality. The impact of perioperative liver dysfunction (LD) on outcome remains unclear and little is known about factors leading to postoperative LD. METHODS: We performed a retrospective, single-center analysis on 285 patients with left-sided IE without pre-existing chronic liver disease referred to our center between 2007 and 2013 for valve surgery. Sequential organ failure assessment (SOFA) score was used to evaluate organ dysfunction. Chi-square, Cox regression, and multivariate analyses were used for evaluation. RESULTS: Preoperative LD (Bilirubin >20 µmol/L) was present in 68 of 285 patients. New, postoperative LD occurred in 54 patients. Hypoxic hepatitis presented the most common origin of LD, accompanied with high short-term mortality. In-hospital mortality was higher in patients with preoperative and postoperative LD compared to patients without LD (51.5, 24.1, and 10.4%, respectively, p < 0.001). 5-year survival was worse in patients with pre- or postoperative LD compared to patients without LD (20.1, 37.1, and 57.0% respectively). A landmark analysis revealed similar 5-year survival between groups after patient discharge. Quality of life was similar between groups when patients survived the perioperative period. Logistic regression analysis identified duration of cardiopulmonary bypass and S. aureus infection as independent predictors of postoperative LD. CONCLUSIONS: Perioperative liver dysfunction in patients with infective endocarditis is an independent predictor of short- and long-term mortalities. After surviving the hospital stay, 5-year prognosis is not different and quality of life is not affected by LD. S. aureus and duration of cardiopulmonary bypass represent risk factors for postoperative LD.

Metabolomic profiling in patients undergoing Off-Pump or On-Pump coronary artery bypass surgery.

BACKGROUND: Coronary artery bypass surgery can be performed without (Off-Pump) or with cardiopulmonary bypass (On-Pump). Extracorporeal circulation and cardioplegic arrest may cause alterations in the plasma metabolome. We assessed metabolomic changes in patients undergoing On-Pump or Off-Pump coronary artery bypass surgery. METHODS: We assessed five analyte classes (41 acylcarnitines, 14 amino acids, 92 glycerophospholipids, 15 sphingolipids, sugars, lactate) using a mass-spectrometry-based kit (Biocrates AbsoluteIDQ® p150) in paired arterial and coronary sinus blood obtained from 10 consecutive On-Pump and 10 Off-Pump patients. Cardioplegia for On-Pump was warm blood Calafiore. On-Pump outcomes were corrected for hemodilution through crystalloid priming. RESULTS: Demographic data were equal in both groups with normal ejection fraction, renal and liver function. Patients received 2.25 ± 0.64 bypass grafts. All postoperative courses were uneventful. Of 164 measured metabolites, only 13 (7.9%) were altered by cardiopulmonary bypass. We found more long-chain acylcarnitines Off-Pump and more short-chain acylcarnitines On-Pump. Glycerophospholipids showed lower concentrations On-Pump and arginine (as the only different amino acid) Off-Pump. Interestingly, plasma arginine (nitric oxide precursor) concentration at the end of surgery correlated inversely with postoperative vasopressor need (r = -0.7; p < 0.001). Assessing arterial/venous differences revealed phosphatidylcholine-production and acylcarnitine-consumption. These findings were unaffected by cardiopulmonary bypass, cardioplegia or temporary vessel occlusion during Off-Pump surgery. CONCLUSIONS: Cardiopulmonary bypass and warm blood cardioplegia cause only minor changes to the metabolomic profile of patients undergoing coronary artery bypass surgery. The observed changes affected mainly acylcarnitines. In addition, there appears to be a relationship between arginine and vasopressor need after bypass surgery.

Effect of pre-operative octenidine nasal ointment and showering on surgical site infections in patients undergoing cardiac surgery.

OBJECTIVE: To evaluate the effect of pre-operative octenidine (OCT) decolonization on surgical site infection (SSI) rates. DESIGN: Before-and-after cohort study. PATIENTS: Patients undergoing an elective isolated coronary artery bypass graft (CABG) procedure: control group (1st January to 31st December 2013), N=475; intervention group (1st January to 31st December 2014), N=428. INTERVENTIONS: The intervention consisted of nasal application of OCT ointment three times daily, beginning on the day before surgery, and showering the night before and on the day of surgery with OCT soap. RESULTS: A median sternotomy was performed in 805 (89.1%) patients and a minimally invasive direct coronary artery bypass procedure was performed in 98 (10.9%) patients. Overall, there was no difference in SSI rates between the control and intervention groups (15.4% vs 13.3%, P=0.39). The rate of harvest site SSIs was significantly lower in patients in the intervention group (2.5% vs 0.5%, P=0.01). Patients who had undergone a median sternotomy in the intervention group had a significantly lower rate of organ/space sternal SSIs (1.9% vs 0.3%, P=0.04). However, there was a trend towards an increased rate of deep incisional sternal SSIs (1.2% vs 2.9%, P=0.08). Multi-variate analysis did not identify a significant protective effect of the intervention (odds ratio 0.79, 95% confidence interval 0.53-1.15, P=0.27). CONCLUSIONS: Pre-operative decolonization with OCT did not reduce overall SSI rates in patients undergoing an elective isolated CABG procedure, but significantly decreased harvest site and organ/space sternal SSIs. Randomized controlled trials, including controlled patient adherence to the intervention, are required to confirm these observations and to determine the clinical utility of OCT in pre-operative decolonization.

Acute mesenteric ischemia following cardiovascular surgery--A nested case-control study.

INTRODUCTION: Acute mesenteric ischemia is a rare but often fatal complication following cardiovascular surgery. Early suspicion may reduce overall mortality. This retrospective study aims to identify predictors and risk factors that may determine the onset and evolution of acute mesenteric ischemia. METHODS: In a retrospective case-control study, we compared co-morbidities and peri-operative risk factors of patients with or without mesenteric ischemia following cardiac surgery using univariate and logistic regression analyses. RESULTS: Of 9385 patients, 108 (1.15%) were diagnosed with acute mesenteric ischemia within two weeks after cardiac surgery. In-hospital mortality was 68% for this group. Patients with ischemia and controls were matched in regard to patient's age and type of surgical intervention and showed similar pre-operative parameters. Only liver cirrhosis (OR 13.3, CI95% 3.6-49.3), and emergency operation (OR 2.6, CI95% 1.3-5.2) remained independent pre-operative predictors for acute mesenteric ischemia in multivariate analysis. In contrast, early postoperative parameters revealed a higher correlation with the occurrence of mesenteric ischemia including the use of norepinephrine (OR 3.5 CI95% 1.6-7.8), epinephrine (OR 2.0, CI95% 1.1-3.7), and serum lactate levels >3 mmol/L (OR 2.9, CI95% 1.5-5.6). A set of key markers of regression analysis was evaluated in a ROC curve analysis. The area under curve was 0.835, which indicates moderate to good prognostic accuracy. CONCLUSION: Early identification of pre- and post-operative predictors including liver cirrhosis, emergency operation, serum lactate >3 mmol/L, and the use of norepinephrine and epinephrine may help facilitate early diagnosis of acute mesenteric ischemia following cardiac surgery, and thus may allow immediate adequate treatment, leading to a reduction in mortality rates.

Comparison between Sequential Organ Failure Assessment score (SOFA) and Cardiac Surgery Score (CASUS) for mortality prediction after cardiac surgery.

BACKGROUND: Our purpose was to evaluate and compare the accuracy of the "Sequential Organ Failure Assessment" score (SOFA) and the "Cardiac Surgery Score" (CASUS) for the prediction of mortality after cardiac surgery. METHODS: Between January 1, 2007 and December 31, 2008 we prospectively included all consecutive adult patients admitted to our intensive care unit (ICU) after cardiac surgery. Both scoring systems were calculated daily from the 1st day in the ICU (day of operation) until the 7th ICU day. We evaluated the ICU mortality prediction of both models using calibration and discrimination statistics. RESULTS: 2801 patients (29.6% females) were included. Mean age was 66.9 ± 10.7 years. Intensive care unit mortality was 5.2%. The calibration of the "Sequential Organ Failure Assessment Score" and "Cardiac Surgery Score" was reliable for all days (p ≥ 0.05). CASUS was more accurate in predicting survival and mortality compared to SOFA for all days, as evidenced by the larger areas under the Receiver Operating Characteristic curves. CONCLUSIONS: Both CASUS and SOFA are reliable mortality prediction tools after cardiac surgery. However, CASUS was more accurate in predicting the individual patient's risk of mortality. Thus, use of the CASUS in cardiac surgery intensive care units is recommended.

KCH, the German preoperative score for isolated coronary artery bypass surgery: is it superior to the logistic EuroSCORE?

BACKGROUND: The accuracy of the logistic EuroSCORE in different patient populations has been questioned. Using the German registry database, the KoronarCHirurgie (KCH) score was introduced as a preoperative risk stratification tool specifically for patients who undergo isolated coronary artery bypass surgery in Germany. However, no direct statistical comparison of this score with the well-established logistic EuroSCORE has been previously performed. The aim of this study was to validate the preoperative German KCH score and to compare it to the logistic EuroSCORE for all coronary artery bypass surgery patients as well as for on-pump and off-pump subgroups. METHODS: We prospectively included all consecutive adult patients admitted to our department between January 1, 2007 and December 31, 2008, who underwent isolated coronary artery bypass surgery. The logistic EuroSCORE and the KCH-3.0 were calculated on admission to hospital. The outcome was defined as 30-day mortality. We performed calibration (Hosmer-Lemeshow test and Anderson-Grunkemeier Observed/Expected "O/E" mortality ratio) and discrimination (receiver operating characteristic "ROC" test) analyses of both scores. The accuracy of the scores was compared using DeLong's test. RESULTS: A total of 1461 patients (23.96 % females, mean age 66.94 ± 9.43 years) were included. The 30-day mortality rate was 2.87 %. The two models were comparable with regard to the prediction of an individual patient's risk of mortality in the whole study population and in the on-pump and off-pump subgroups (according to the ROC test and DeLong's test). Overall, there was no significant difference between observed and expected mortality according to the Hosmer-Lemeshow test ( P > 0.05). However, the KCH-3.0 was far less likely to overpredict mortality than the logistic EuroSCORE, as demonstrated by the observed mortality/expected mortality (O/E) ratios. The O/E ratio was 0.32 for the logistic EuroSCORE and 0.74 for the KCH-3.0. For the on-pump subgroup the O/E ratios were 0.37 and 0.80, respectively, and 0.24 and 0.63, respectively, for the off-pump subgroup. CONCLUSIONS: The KCH-3.0 is more reliable than the logistic EuroSCORE as a preoperative mortality prediction score for patients undergoing isolated coronary artery bypass surgery, providing predicted mortality rates that are closer to the actual mortality rates with a lower overprediction of mortality.

Surgical treatment of an aorto-right atrial fistula as a complication of tricuspid valve repair.

UNLABELLED: We report a case in which implantation of a rigid tricuspid annuloplasty ring resulted in an aorto-atrial fistula. In addition the patient had a series of complications which had occurred in the perioperative management of the initial operation, characterized by reoperation for mitral and tricuspidal ring dehiscence, and two reopenings for bleeding as well as postoperative sepsis. The attempt to close the fistula on the arrested heart failed. On presentation to our hospital the patient was in decompensated heart failure (NYHA class IV, ascites and pulmonary edema). Our surgical approach (fifth resternotomy) consisted of mitral valve replacement under cardioplegic arrest and re-tricuspid valve repair and closure of the AV fistula on the beating heart. Postoperatively, the patient was extubated on postoperative day one and discharged on postoperative day 41 in NYHA class II. CONCLUSION: Performing a right heart procedure on the beating heart allowed proper identification of the fistula and easy closure.

Late onset Takotsubo cardiomyopathy after mitral valve replacement.

We report a case of delayed onset Takotsubo cardiomyopathy (TC) in a 69-year-old woman, associated with minor stressors, two weeks after mitral valve replacement. After suffering several minor complications she had fully recovered and her discharge was planned. On the 14th postoperative day she had to be resuscitated due to cardiogenic shock. TC was diagnosed based on reduced ventricular function with apical ballooning and normal coronaries. Treatment with catecholamines and intra-aortic balloon pump led to full recovery. She continues to do well two years after surgery. TC should be considered as a potential cause of delayed ventricular dysfunction in postcardiac surgery patients.

Surgical therapy of ventricular arrhythmias.

Since the advent of implantable cardioverters/defibrillators (ICD) and percutaneous ablation, surgery for the treatment of ventricular arrhythmia has decreased tremendously. Nevertheless, surgical treatment of ventricular arrhythmias is still required, especially for cases where ICD discharge occurs very frequently or in patients with other indications for surgery. The choice of surgical therapy may range from radiofrequency- or cryoablation of a single focus (identified either intra- operatively or percutaneously) to more extensive surgical procedures such as surgical ventricular reconstruction with endocardial resection or even resection of the right ventricle and the creation of a cavo-pulmonary circulation for malignant arrhythmias and right ventricular failure in patients with arrhythmogenic right ventricular dysplasia. However, the choice of surgical procedure should be made based on the pathomechanism of the arrhythmia. This is important because any incision in the left or right ventricle or percutaneous ablation may also be the cause for ventricular arrhythmia. In this short review we will describe the most common underlying substrates for ventricular arrhythmia, indications for surgery, the techniques used for treatment and the results achieved. We will conclude that for most cases of patients with ventricular arrhythmia undergoing surgery, ischemia and the presence of a scar after myocardial infarction is the underlying cause and revascularization plus surgical ventricular reconstruction with endocardial resection may be the best treatment option.

Differential gene expression in response to ventricular unloading in rat and human myocardium.

UNLABELLED: Left ventricular unloading by mechanical assist devices induces myocardial atrophy. We aimed to systematically identify differentially expressed genes in a model of physiological atrophy (unloading of healthy rat myocardium) and compare these changes to those in a unloaded, failing human heart. METHODS: Atrophy in rat hearts was induced by heterotopic transplantation of a donor heart into the abdomen of an isogenic recipient. After one week, donor and recipient RNA was isolated. Differential gene expression was assessed by subtractive hybridization. Two screens with radioactive probes were performed to verify differentially expressed clones. Positive clones were sequenced and cDNA of genes of known homology were used as probes for hybridization with RNA from separate atrophied rat hearts and human tissue from a normal, failing or failing and unloaded left ventricle. RESULTS: We picked 1880 clones from the subtractive hybridization procedure (940/940: forward/reverse runs assessing up- or down-regulation, respectively). The first screen verified 465/140 and the second screen verified 67/30 clones. 24/23 clones were sequenced and 14/10 homologies to known genes were found. In the atrophied heart, respiratory chain and metabolic genes were down-regulated (NADH-DH, cytochrome c oxidase, acetyl-CoA synthetase, myoglobin) and cellular recognition and stress genes were up-regulated (MHC1 and 2, HSP70). In the human heart, cytochrome c oxidase, acetyl-CoA synthetase, and myoglobin expression was increased in the failing heart and returned to normal with unloading. Unloading also resulted in up-regulation of HSP70. CONCLUSIONS: The genetic responses of failing human and healthy rat myocardium to mechanical unloading show similarities that appear to be independent of species differences and/or underlying disease. Thus, heterotopic heart transplantation is a relevant model for investigating the mechanisms of mechanical unloading.

Long-term results of bioprosthetic mitral valve replacement: the pericardial perspective.

Pericardial valve bioprostheses were introduced in early 1970s and were widely used in the 1980s. The longterm results with the Ionescu-Shiley valve, the first commercially available pericardial valve, were disappointing because of high rate cusp tears during the first decade after implantation. The enthusiasm for this type of bioprosthetic valve was further hampered by the premature failure of the Hancock pericardial valve. The long-term results of aortic valve replacement with the Carpentier-Edwards pericardial valve, which was introduced in 1981, indicated that that valve was durable and the issue of cusp tears had been resolved by an appropriate design. This knowledge prompted surgeons to revisit the merits of pericardial valves for mitral valve replacement and several other pericardial valves are now commercially available. The largest data on long-term results are with the Carpentier-Edwards pericardial mitral valve. The reported freedom from structure valve failure ranged from 69% to 85% at 10 years in patient population with mean age of 60 to 70 years. Young age is a major determinant of valve failure, which is largely due to calcification. There are also long-term data, albeit more limited on the Sorin Pericarbon and Mitroflow valves used for mitral valve replacement. This paper review the published experience with various pericardial bioprosthetic valves used for mitral valve replacement during the past 3 decades.

Experimental model for heart failure in rats--induction and diagnosis.

BACKGROUND: Clinical heart failure is generally preceded by hypertrophy. Many animal models (e. g. toxic heart failure models) do not consider this hypertrophy. We set out to develop a heart failure model in rats by inducing pressure-overload hypertrophy. METHODS: We induced coarctation of the aortic arch with a tantalum clip (0.35 mm internal diameter) In 3-week-old rats (n=17). Starting at seven weeks postoperatively, we measured ejection fraction (EF), fractional shortening (FS), end-systolic (LVESD) and end-diastolic (LVEDD) left ventricular dimensions by echocardiography each week. Heart, lung, and liver specimens were analyzed histopathologically at least eleven weeks after the operation. RESULTS: Contractile function was significantly decreased in hearts from animals with aortic banding (EF: 45+/-5% vs. 73+/-5%, p<0.01; FS: 20+/-3% vs. 35+/-5%, p<0.01). At the same time, left ventricles were dilated (LVEDD: 9.1+/-0.6 mm vs. 7.4+/-0.5 mm; LVESD: 7.3+/-0.6 mm vs. 4.8+/-0.4 mm, p<0.01). These observations were associated with clinical and histopathological changes characteristic for chronic left heart failure. CONCLUSION: Placing a tantalum clip around the aortic arch in 3-week-old rats consistently induces left ventricular decrease in contractile function and dilatation after eleven weeks.

The Jarvik 2000 is associated with less infections than the HeartMate left ventricular assist device.

OBJECTIVES: Device-related infections remain a considerable problem of left-ventricular support. We compared the device-related-infections between the HeartMate left ventricular assist device (LVAD) and the Jarvik 2000 permanent LVAD, a device with a novel retroauricular power-supply. METHODS: Between December 2000 and September 2002 we implanted the HeartMate-vented, electrical-system in 11 patients and the permanent Jarvik 2000 in six patients. Total support time was 1626 patient-days (HeartMate, 26-271 days) versus 1246 patient-days (Jarvik 2000, 8-411 days). As potential risk factors for infection we analyzed age, preoperative hospital-days, total protein, cardiac index, maximal oxygen uptake, use of inotropes, LVAD risk-score-index and Aaronson-Mancini-score, intubation time, and intensive care unit stay. We used the Center of Disease Control definitions for surgical site infections. RESULTS: HeartMate-patients were younger than Jarvik 2000 patients (46+/-13 versus 58+/-6 years, P=0.056), there were no other differences in the risk factors. Four HeartMate-patients needed late (>or=48 h) surgical revisions for bleeding/hematomas versus no revisions in the Jarvik 2000 patients. In the HeartMate-patients, there were seven (64%) driveline-infections, five (45%) device-pocket infections, and three (27%) bloodstream-infections, or 0.43 device-related infections/100 patient-days. Infections occurred early (34+/-31 days). Three patients required urgent transplantation due to bloodstream infection. There were no adverse outcomes in the HeartMate-group due to infection. In the Jarvik 2000 patients, there was one driveline-infection (16%) after 270 days of support (0.08 device-related infections/100 patient-days), significantly less than in the HeartMate-group (P=0.044). Driveline infections resolved with antibiotics and local wound care in the Jarvik 2000 patient, but only in one of seven HeartMate-patients. CONCLUSIONS: Implantation of the Jarvik 2000 is associated with less device-related infections than the HeartMate-LVAD. The power-supply of the permanent Jarvik 2000 is suitable for long-term mechanical support.

Load-induced changes in vivo alter substrate fluxes and insulin responsiveness of rat heart in vitro.

It has been observed that opposite changes in cardiac workload result in similar changes in cardiac gene expression. In the current study, the hypothesis that altered gene expression in vivo results in altered substrate fluxes in vitro was tested. Hearts were perfused for 60 minutes with Krebs-Henseleit buffer containing glucose (5 mmol/L) and oleate (0.4 mmol/L). At 30 minutes, either insulin (1 mU/mL) or epinephrine (1 micromol/L) was added. Hearts weighed 35% less after unloading and 25% more after aortic banding. Contractile function in vitro was decreased in transplanted and unchanged in banded hearts. Epinephrine, but not insulin, increased cardiac power. Basal glucose oxidation was initially decreased and then increased by aortic banding. The stimulatory effects of insulin or epinephrine on glucose oxidation were reduced or abolished by unloading, and transiently reduced by banding. Oleate oxidation correlated with cardiac power both before and after stimulation with epinephrine, whereas glucose oxidation correlated only after stimulation. Malonyl-coenzyme A levels did not correlate with rates of fatty acid oxidation. Pyruvate dehydrogenase was not affected by banding or unloading. It was concluded that atrophy and hypertrophy both decrease insulin responsiveness and shift myocardial substrate preference to glucose, consistent with a shift to a fetal pattern of energy consumption; and that the isoform-specific changes that develop in vivo do not change the regulation of key metabolic enzymes when assayed in vitro.

Serious complications that require surgical interventions after endoluminal stent-graft placement for the treatment of infrarenal aortic aneurysms.

BACKGROUND: Endoluminal stent-graft placement for the treatment of infrarenal abdominal aortic aneurysms has gained widespread acceptance because it is associated with lower peri-interventional morbidity than conventional transabdominal surgery. In this study the long-term morbidity of the procedure was evaluated. METHODS AND RESULTS: Between September 1994 and December 1998, 150 patients (age, 69.6 +/- 8.49 years; 142 men, 8 women) with abdominal aortic aneurysms were treated with the placement of an intravascular nitinol stent-graft (Stentor [55] and Vanguard-System [95]); there were eight tubular grafts and 142 bifurcated grafts. Initial placement of the stent-graft was successful in 144 patients. Mean follow-up was 49 +/- 25 months. In 13.3% of stent-graft placements we encountered the following complications: 4 cases of migration or dislocation of the prosthesis (30.5 +/- 7.4 months after placement); 2 ruptures of the aorta (26.7 and 15.0 months after placement); 3 recurrent thromboses of the stent-graft (25.5 +/- 5.3 months after placement); 3 endoleaks (27.5 +/- 15.7 months after placement); and 5 infections of the prosthesis (26.6 +/- 16.5 months after placement). There was no correlation between the complications and the type of stent used. All of these patients were treated by surgical replacement of the prosthesis with a Dacron graft. CONCLUSIONS: (1) The results suggest that most complications are due to a continuation of the disease process leading to loosening of the prosthesis. (2) Explantation of the prosthesis and surgical repair is feasible but bears additional risks. (3) Because the onset of reperfusion of the excluded aneurysm cannot be predicted, all patients with infrarenal aortic stent-grafts require frequent computer tomographic follow-up. (4) Finally, the results call for further improvements in the design of the stent-graft.

A technique of heterotopic, infrarenal heart transplantation with double anastomosis in mice.

Mouse heart transplantation is frequently used to investigate mechanisms of rejection and immune response. A fully vascularized technique is presented in which the graft ascending aorta is anastomosed end-to-side to the recipient's aorta and the pulmonary aorta is anastomosed end-to-side to the inferior vena cava using 11-0 Ethilon suture. We suggest that this double anastomosis technique is a valuable tool to investigate immune mechanisms in mice.