Dysfunction of alveolar macrophages after cardiac surgery and postoperative pneumonia?--An observational study.

INTRODUCTION: Patients undergoing cardiac surgery have an increased risk of postoperative pneumonia. Pulmonary immune dysfunction might be a contributing factor. We therefore determined changes of the surface molecules on alveolar macrophages (AMs). To characterize modulation in patients with pneumonia we correlated these changes to the development of postoperative pneumonia. METHODS: After ethical approval and written informed consent, 33 patients undergoing elective coronary bypass grafting surgery were included in this observational study. Peripheral blood cells and alveolar lavage fluid were collected directly after induction of anesthesia and two hours after separation from cardiopulmonary bypass (CPB). Human leukocyte antigen-DR (HLA-DR) and toll-like receptors (TLR) 2/4 expression on monocytes and AM were assessed by flow cytometry. A total of three patients developed postoperative pneumonia determined according to the criteria of the Center of Disease Control. Statistical analysis was performed with the Mann-Whitney-U test and Wilcoxon test. RESULTS: We found significant changes of phenotypic and functional immune markers on AMs after cardiac surgery. HLA-DR expression on peripheral blood monocytes and AMs was significantly reduced compared to baseline in all patients (each approximately 30%). After surgery patients who developed postoperative pneumonia revealed a trend of stronger reduction of HLA-DR expression (83.7% versus 27.1%) and TLR4 expression on AMs (46.1% versus 9.9%) compared to patients without pneumonia. Already before surgery, the baseline of TLR2 expression on AM was significantly lower (27.7%) in patients who developed postoperative pneumonia. CONCLUSIONS: As far as we know this is the first study that shows an early impairment of lung cellular immune response after cardiac surgery. These findings can help to understand the role of cell-mediated immunosuppression and its association to the development of postoperative pneumonia.

Clinical experience with the ATS 3F stentless aortic bioprosthesis: five years' follow up.

BACKGROUND AND AIM OF THE STUDY: The ATS 3F aortic bioprosthesis is an equine pericardial stentless valve used for aortic valve replacement (AVR). The study aim was to determine the incidence of valve-related events during a five-year follow up period. METHODS: Between 2002 and 2003, a total of 35 patients (mean age 73 +/- 6 years; range 61-86 years) underwent AVR with the ATS 3F valve implanted in the subcoronary position, utilizing a single running suture technique. The mean valve size was 26.0 +/- 1.9 mm. Prior to surgery, all patients were in NYHA class III or IV. The hemodynamic performance of the valve was assessed after one, three, and five years by means of transthoracic echocardiography. Clinical outcome was evaluated by either physical examination or by telephone interviews with the primary care physicians. RESULTS: The total patient follow up was 123 patient-years. Four patients (11%) were lost to follow up. The overall survival was 86%, and none of the deaths was valve-related. Up to five years, no severe structural or non-structural valve dysfunction was identified in the followed patients. Freedom from severe adverse events (SAE) was 89%; the SAE included one permanent and three transient neuroembolic events, but echocardiographic examinations of these patients were unsuggestive for thrombotic depositions on the prosthetic valves. Freedom from endocarditis was 100%. Minimal paravalvular regurgitation was detected in four patients; this was of no clinical importance, and resulted in a 100% freedom from reoperation. The mean transvalvular pressure gradients were 12.9 +/- 6.3, 11.2 +/- 4.2, and 15.2 +/- 5.3 mmHg at one, three, and five years, respectively. The left ventricular mass and NHYA class were each improved significantly during the observation period. The left ventricular geometries showed also a trend towards improvement. CONCLUSION: The ATS 3F aortic valve prosthesis continues to perform with satisfactory hemodynamic results, comparable to those of other pericardial valves. With minimal SAE, the prosthesis demonstrated excellent intermediate-term clinical results and--to date--is proving to be durable.

Early outcome after surgery for active native and prosthetic aortic valve endocarditis.

BACKGROUND AND AIM OF THE STUDY: Today, the in-hospital mortality of patients treated surgically for active aortic native and prosthetic valve endocarditis remains high. The study aim was to identify the preoperative and intraoperative predictors of early outcome. METHODS: Between January 2004 and December 2006, 75 patients (57 males, 18 females; mean age 61.6 +/- 14.1 years) underwent surgery for active native valve (NVE) or prosthetic aortic valve endocarditis (PVE). RESULTS: Active aortic NVE was present in 49 patients (65.3%), and PVE in 26 (34.7%). Staphylococcus species were the most common infecting microorganisms in both groups, while 20 cases (26.7%) were culture-negative. Except for significantly higher preoperative renal failure (RF) in patients with PVE (p = 0.01), the clinical characteristics were equally distributed. Four patient subsets were identified based on the extent of the infectious process: (i) locally controlled NVE (38.7%); (ii) locally uncontrolled NVE (26.7%); (iii) locally controlled PVE (14.6%); and (iv) locally uncontrolled PVE (20%). Aortic valve replacement (AVR) was performed with a stentless bioprosthesis in 53 cases (70.7%), a mechanical prosthesis in eight (10.6%), and a Ross procedure in 14 (18.7%). Concomitant active mitral valve endocarditis was treated in 17 patients (22.7%). Associated procedures were performed in 14 cases (18.7%). The in-hospital mortality was 24% (n = 18). Female gender (p = 0.0147), preoperative septic or cardiogenic shock (p = 0.0275) and previous embolic events (p = 0.0129) were identified as independent predictors for in-hospital mortality. Eight late deaths occurred; the estimated overall actuarial survival was 66.6 +/- 5.6% at 12 months and 60.7 +/- 6.5% at 24 months. On Cox multiple regression, age > 70 years (p = 0.0113), preoperative RF (p = 0.0015) and mitral valve surgery due to concomitant infective endocarditis (p = 0.0363) were significant adverse predictors of late death. CONCLUSION: Surgery for active aortic valve infective endocarditis is associated with high operative mortality and morbidity. Failure of antibiotic therapy causing septic or cardiogenic shock and delayed referral to surgery may have a detrimental effect on early outcome. Surgical eradication of cardiac infections should always be associated with the treatment of extracardiac septic foci, which could maintain a septic state and adversely influence early outcome. Adhesion to surgical guidelines, together with a multidisciplinary approach, may have a major impact on the early prognosis of these high-risk patients.

Aortic valve replacement with new-generation stentless pericardial valves: short-term clinical and hemodynamic results.

BACKGROUND AND AIM OF THE STUDY: Aortic valve replacement (AVR) with stentless bioprostheses offers superior hemodynamics. In order to overcome the disadvantages of older, stentless valves, a new generation of pericardial stentless prostheses has been developed. Herein, the hemodynamic and clinical results of these substitutes have been evaluated. METHODS: Between March 2002 and May 2004, 85 patients (59 females, 26 males; mean age 73.6 +/- 6.1 years) who underwent AVR received either a bovine (Sorin Pericarbon Freedom; SPF; n = 50) or an equine (3F Aortic Bioprosthesis; 3F; n = 35) pericardial stentless valve. Patients were followed up prospectively at six months after surgery by clinical and echocardiographic examination. The mean follow up period was 5.6 +/- 0.8 months, and was 96.4% complete. RESULTS: Mortality was 2.4% at 30 days (two SPF patients; one died at reoperation for suspected valve thrombosis and one was a non-valve-related death) and 2.5% at follow up (two SPF patients; both nonvalve-related). Neither structural valve failure nor endocarditis were observed. Preoperatively, there were no differences in baseline data, functional status and hemodynamics between SPF and 3F patients. The aortic cross-clamp time was similar in both groups (51.7 +/- 11.2 min for SPF; 51.6 +/- 8.2 min for 3F). NYHA functional status improvement was similar in each group (1.8 +/- 0.5 for SPF; 1.7 +/- 0.6 for 3F). The mean transaortic pressure gradient (deltapmean) was reduced in all patients during follow up. With SPF, a lower deltapmean was found for smaller aortic roots (indexed annular diameter (IAD) < 14 mm/m2) as well as in larger (IAD > 14 mm/m2) aortic roots: 8.0 +/- 4.5 mmHg versus 13.2 +/- 7.2 mmHg (p < 0.05) and 6.8 +/- 3.0 mmHg versus 12.8 +/- 4.8 mmHg (p < 0.05), respectively. CONCLUSION: New-generation pericardial stentless aortic valves are very pliable, which facilitates their implantation. Clinical and hemodynamic results with these prostheses are promising. The SPF prosthesis demonstrates excellent performance, and may be superior when implanted in small aortic roots.

Use of an antimicrobial skin sealant reduces surgical site infection in patients undergoing routine cardiac surgery.

BACKGROUND: With high morbidity and potentially devastating consequences, surgical site infections (SSIs) after cardiac surgery add substantially to the healthcare burden. Inhibiting migration of skin microbes is likely to reduce contamination of the surgical incision by endogenous potential pathogens. We studied the effect of treatment with a cyanoacrylate-based antimicrobial skin sealant (INTEGUSEAL®) on the SSI rate in cardiac surgery patients. METHODS: In a consecutive series of 910 prospective patients undergoing routine cardiac surgery, standard pre-operative preparation was performed on 721 patients of whom 189 also received antimicrobial skin sealant. A further 189 consecutive patients who received only standard pre-operative care were studied retrospectively. The primary study endpoint was occurrence of superficial or deep SSI according to the definitions of the U.S. Centers for Disease Control and Prevention. RESULTS: The mean (standard deviation) SSI risk score based on combined pre-operative and intra-operative factors according to the Society of Thoracic Surgeons risk scoring system was significantly higher for the skin sealant group (9.1±1.0) than for the prospective (7.1±3.2; p<0.001) and retrospective (8.7±0.8; p<0.001) control groups. Surgical site infections occurred in two patients (1.1%) in the sealant group, 33 patients (4.6%) in the prospective control group (p<0.025), and nine patients (4.8%) in the retrospective control group (p<0.032). CONCLUSIONS: When added to existing pre-operative measures to reduce bacterial contamination of surgical incisions that are employed routinely at this cardiovascular surgery unit, use of antimicrobial skin sealant decreased the incidence of SSI in cardiac surgery patients.

A retrospective non-randomized study on the impact of INTEGUSEAL, a preoperative microbial skin sealant, on the rate of surgical site infections after cardiac surgery.

OBJECTIVE: Surgical site infection (SSI) remains a serious potential complication after cardiac surgery. This study evaluated the impact of a cyanoacrylate microbial skin sealant (INTEGUSEAL) on the rate of SSI in cardiac surgery patients. METHODS: Between January 2006 and July 2008, 580 patients underwent cardiac surgery by a single surgeon (PMD). Standard preoperative skin preparation was performed in 280 patients (control group), and 300 patients (microbial skin sealant group) received microbial skin sealant in addition to standard preoperative preparation. Patient characteristics and preoperative and combined pre/intraoperative risk scores were evaluated. The primary study endpoint was freedom from SSI within 30 days. RESULTS: Both groups were established in a 15-month period. Carotid artery disease, diabetes mellitus, congestive heart failure, previous cardiac surgery, and bilateral internal mammary artery use were significantly more common in the skin sealant group. Preoperative risk scores for the development of SSI in the two groups were similar. In the skin sealant group, the combined operative risk score for SSI was significantly higher (9.8±4.0 vs. 8.7±3.7; p<0.001) nevertheless the incidence of SSI was significantly lower (2.3% vs. 6.8%; p=0.011) than in the control group. CONCLUSION: Changing a surgeon's standard preoperative practice by including a microbial skin sealant pretreatment significantly reduced the rate of SSI.

Mycotic pseudoaneurysm of the ascending aorta at site of aortic cannulation.

Reoperation for pseudoaneurysm of the ascending aorta presents a surgical challenge. Instituting femorofemoral bypass and establishing hypothermic circulatory arrest is a well-known strategy, although not free from complications. We report a case of mycotic pseudoaneurysm after coronary artery bypass in a 53-year-old man, at the site of previous aortic cannulation, and review the surgical strategies proposed to manage this pathologic entity.

The effect of surface roughness on activation of the coagulation system and platelet adhesion in rotary blood pumps.

The surface roughness of left ventricular assist devices (LVADs) is important for the biocompatibility of blood pumps. However, little is known about the effect of surface roughness on the antithrombogenicity of the device. The present study investigated the effect of surface roughness on the activation of the coagulation system and platelet adhesion in an impeller-type blood pump. Three identical Baylor Gyro 710 centrifugal blood pumps (Baylor College of Medicine, Houston, TX, USA) were manufactured with impeller surface roughness of 0.05, 0.2, and 0.4 microm, respectively, as determined by a stylus profilometer and by scanning electron microscopy. Whole blood was anticoagulated (1-IU heparin/mL, ACT 250 s) and circulated for 60 min in an artificial circulatory system, simulating LVAD perfusion (5-L/min flow against 100 mm Hg). Enzyme-linked immunosorbent assays were developed to quantify fibrinogen- and von Willebrand factor (vWf) adsorption as well as platelet adhesion directly on the impellers of the pumps. Levels of prothrombin fragment F1.2 and thrombin-antithrombin (TAT) complex were measured in order to quantify activation of coagulation. Compared with the 0.05-microm surface, platelet adhesion was 40 and 76% higher on the 0.2- and 0.4-microm surface, respectively (P < 0.01). The evaluation of adsorbed fibrinogen and vWf showed significant higher protein antigen levels on the rougher surfaces (P < 0.01). Furthermore, nonpulsatile perfusion activated the coagulation system. By contrast, the surface roughness had no significant influence on plasma prothrombin F1.2 fragment- and TAT concentrations. Antithrombogenicity was significantly reduced in pumps with inferior metal-finishing quality.