The Characteristics of Postoperative Mediastinitis During the Changing Phases of Cardiac Surgery.

BACKGROUND: Mediastinitis is a serious complication of open heart surgery associated with high mortality, considerable health care costs, and prolonged hospital stay. We examined characteristics and incidence of mediastinitis during 29 years when indications and patient material have been in a process of change. METHODS: This was a retrospective population-based study comprising all mediastinitis patients more than 16 years of age after open heart surgery between 1990 and 2018 from a population of 1.7 million. Patient records of 50 mediastinitis patients from 2004 to 2014 were reviewed and compared with 120 patients from 1990 to 1999. RESULTS: Annual mediastinitis rate varied 0% to 1.5% with a decreasing trend-from a level exceeding 1.2% to approximately 0.3%-over the study period. In 2004 to 2014 patients with mediastinitis were older, more often smokers, and more often had diabetes mellitus and renal insufficiency than in 1990 to 1999. No difference in length of hospital treatment, antibiotic prophylaxis or treatment, intensive care unit treatment, or mortality was observed between 1990 to 1999 and 2004 to 2014. Coronary artery bypass graft surgery became less common and valve replacement and hybrid operations more common among operations leading to mediastinitis. Staphylococcus aureus increased (from 25% to 56%, p = .005) whereas coagulase-negative staphylococci (46% to 23%, P < .001) and gram-negative bacteria (18% to 12%, P = .033) decreased as causative agents. Surgery for mediastinitis remained similar except introduction of vacuum-assisted closure treatment. CONCLUSIONS: The rate of mediastinitis decreased during these 29 years. No difference in 30-day mortality in mediastinitis was seen: 0.9% in 1990 to 1999 and 2% in 2004 to 2014.

Fatal complications after use of the Symmetry Aortic Connector in coronary artery bypass surgery.

During the last 2 years, 103 aortic saphenous vein graft anastomoses were performed in 68 patients undergoing off-pump coronary artery bypass by using the Symmetry Bypass System Aortic Connector. Of these patients, 2 died during the early postoperative period. In the first patient, after an episode of ventricular fibrillation and closed-chest cardiac massage, the sternum was opened and hemopericardium secondary to leakage of the proximal anastomotic device was found. The second patient died of ascending aortic dissection, the tear of which was likely to have originated from the proximal anastomotic site.

Preoperative C-reactive protein and outcome after coronary artery bypass surgery.

BACKGROUND: C-reactive protein (CRP) is a predictor of early and late outcome after coronary angioplasty, but there is scant data on its impact on the outcome after coronary artery bypass grafting (CABG). METHODS: The predictive value of preoperative CRP was evaluated in a series of 764 patients who underwent on-pump CABG. RESULTS: During the in-hospital stay, 13 patients (1.7%) died, 45 (4.5%) developed low cardiac output syndrome, and 28 (3.7%) suffered minor or major cerebrovascular complications. Patients with a preoperative serum concentration of CRP>/=1.0 mg/dL had a higher risk of overall postoperative death (5.3% vs 1.1%, p = 0.001), cardiac death (4.4% vs 0.8%, p = 0.002), low cardiac output syndrome (8.8% vs 3.7%, p = 0.01), and any cerebrovascular complication (4.4% vs 3.5%, p = 0.66). Preoperative serum concentration of CRP>/=1.0 mg/dL was significantly more frequent among patients with history of myocardial infarction, diabetes, lower limb ischemia, low left ventricular ejection fraction, NYHA class IV, and in those undergoing urgent or emergency operation. At multivariate analysis, preoperative serum concentration of CRP >/= 1.0 mg/dL (p = 0.01, O.R.: 6.97) and left ventricular ejection fraction (p = 0.01, O.R.: 0.95) were independent predictors of postoperative death. Postoperative mortality rate was 0.3% among patients with preoperative CRP < 1.0 mg/dL and an ejection fraction >/=50%, whereas it was 21.4% among those with a preoperative CRP >/= 1.0 mg/dL and an ejection fraction less than 50% (p < 0.0001). CONCLUSIONS: Preoperative serum concentration of CRP in patients undergoing on-pump coronary artery bypass surgery is an important determinant of postoperative outcome.

Evidence for an altered balance between matrix metalloproteinase-9 and its inhibitors in calcific aortic stenosis.

BACKGROUND: Recently, aortic valve stenosis has been demonstrated to exhibit increased expression of certain matrix metalloproteinases (MMPs), and this has relevantly raised the question about possible interdependency between these and their tissue inhibitors. We sought to assess the expression of elastolytic MMPs and their inhibitors (TIMPs) in nonrheumatic aortic stenosis. METHODS: The study comprised 30 stenotic and six noncalcified human aortic valves. To measure the expression levels and the amount and molecular forms of gelatinases (MMP-2, MMP-9) and TIMPs (1, 2), in situ hybridization, gelatin zymography, and reverse zymography were carried out. Antielastin staining by a monoclonal BA-4 antibody was performed to investigate the changes of one of the main substrates of these MMPs, and to substantiate the nature of the putative MMP- synthesizing cell. The cases were also immunostained with an antibody to alpha-smooth muscle actin. Inflammatory cell characterization was managed by monoclonal mouse antibodies (UCHL-1, L26, and PGM-1). RESULTS: Compared with the controls, the calcific valves showed increased mRNA expression and activation of MMP-9, and this was associated with typical characteristics of valve disease. MMP-2 mRNA production was rare, but proMMP-2 protein was detected in all valves. In agreement with the interdependency between MMP-9 and its inhibitors, a suggestive imbalance came out in diseased valves. CONCLUSIONS: The disproportion between MMP-9 and its tissue inhibitors may favor a persistent MMP activation state within the calcific valve and likely contribute to the valvular remodeling process in the setting of developing aortic stenosis.

Topical head cooling during rewarming after experimental hypothermic circulatory arrest.

BACKGROUND: The aim of this study was to evaluate the potential neuroprotective effect of topical head cooling during the first 2 postoperative hours after experimental hypothermic circulatory arrest. METHODS: Twenty pigs underwent a 75-minute period of hypothermic circulatory arrest and were randomly assigned to rewarming to 37 degrees C or to undergo topical cooling of the head for 2 hours from the start of rewarming followed by a period of external rewarming to 37 degrees C. RESULTS: The 7-day survival rate was 70% in the control group and 60% in the topical head cooling group. Despite brain tissue oxygenation, intracranial pressures, mixed oxygen venous saturation, oxygen consumption, and extraction tended to be favorable in the topical head cooling group as a clear effect of mild hypothermia. The latter group had significantly higher postoperative brain lactate and pyruvate ratios, and lactate and glucose ratios. Furthermore, the topical head cooling group had worse fluid balance throughout the postoperative period. Brain histopathologic scores were comparable with the study groups, but among 7-days survivors these scores tended to be worse in the topical head cooling group. CONCLUSIONS: Topical cooling of the head during the first 2 postoperative hours after experimental hypothermic circulatory arrest does not appear to provide any neuroprotective effect.

Effect of aneurysm on the tensile strength and biomechanical behavior of the ascending thoracic aorta.

BACKGROUND: Rupture of an ascending thoracic aortic aneurysm (ATAA), which is associated with significant mortality, occurs when the mechanical forces acting on the aneurysm exceed the strength of the degenerated aortic wall. The purpose of this study was to evaluate changes in biomechanical properties of the aortic wall related to ATAA formation. METHODS: Ascending thoracic aortic aneurysm tissue was obtained from surgery; control (nonaneurysmal) aorta was obtained from autopsy. Tissue strips with longitudinal (LONG) or circumferential (CIRC) orientation were stretched to failure. Maximum tissue stiffness and tensile strength were determined from plots of stress (normalized force) versus strain (normalized deformation). Student's t test was used for all comparisons. RESULTS: Tensile strength of LONG (nATAA = 17, n(control) = 7) and CIRC (nATAA = 23, n(control) = 7) ATAA specimens were 29% and 34% less than that of control tissue, respectively (p < 0.05). Maximum tissue stiffness was 72% stiffer for LONG ATAA (p < 0.05) and 44% stiffer for CIRC ATAA (p = 0.06) than for control tissue, respectively. CONCLUSIONS: The data suggest that ATAA formation is associated with stiffening and weakening of the aortic wall, which may potentiate aneurysm rupture.

Endovenous obliteration with radiofrequency-resistive heating for greater saphenous vein insufficiency: a feasibility study.

PURPOSE: To assess the feasibility, safety, and clinical utility of ultrasound (US)- and fluoroscopy-guided endovenous saphenous vein obliteration with radiofrequency (RF)-resistive heating in the treatment of primary venous insufficiency. MATERIALS AND METHODS: Thirty legs of 27 patients with mild to moderate varicose veins and primary greater saphenous vein (GSV) insufficiency diagnosed with duplex US were treated. An endovenous catheter was inserted via US-guided percutaneous puncture or a skin incision. Fluoroscopy and US were used to locate the electrodes at the saphenofemoral junction. GSVs were occluded with RF-resistive heating. Local phlebectomies or sclerotherapy were performed in all procedures to treat varicose veins and teleangiectases. Persistence of vein occlusion and complications potentially attributable to endovenous treatment were assessed at 1 week, 6 weeks, 3 months, 6 months, and 1 year. RESULTS: The mean follow-up time was 9.6 months (SD, 3.8 mo). By the time of the last follow-up visit, occlusion of the treated segment of the GSV had been achieved in 22 legs (73.3%). Persisting patency or recanalization of the GSV was detected in eight legs (26.7%). One patient (3.3%) had varicosity-related symptoms, and three treated legs (10%) had recurrent or new varicosities. Postoperative complications included saphenous nerve paresthesia in three legs (10%) and thermal skin injury in one limb (3.3%). CONCLUSION: Endovenous obliteration employing RF-resistive heating is a relatively safe and promising minimally invasive technique for the treatment of primary GSV insufficiency.