Baseline oxygen delivery is associated with an increased risk of severe postoperative complications after elective open repair of abdominal aortic aneurysm.

AIM: Oxyhemodynamic parameters have been shown to have a relevant impact on the immediate postoperative outcome after major surgery, but it is not known their specific impact on the outcome after elective repair of abdominal aortic aneurysm (AAA). METHODS: One-hundred and forty-one patients underwent elective open repair of infrarenal AAA and hemodynamic parameters were monitored perioperatively. RESULTS: One patient (0.7%) died postoperatively, 23 (16.3%) experienced a myocardial ischemic event and 9 of them (6.4%) had a myocardial infarction. Baseline oxygen delivery was not predictive of such myocardial ischemic events. Thirty-three patients (23.4%) suffered severe postoperative complications. The median baseline oxygen delivery was 429.5 mL/min/m2 among patients who had severe postoperative complications, whereas it was 505.5 mL/min/m2 among those who did not have severe complications (p=0.03). However, this parameter did not retain its significance at multivariate analysis. When only the preoperative variables were included in the logistic regression model, the Glasgow Aneurysm Score (P=0.004, Oddsratio 1.94, 95% C.I. 1.24-3.05) was the only predictor of severe postoperative complications. The Glasgow Aneurysm Score was significantly correlated with baseline oxygen delivery (P=-0.256, P=0.003). CONCLUSIONS: Baseline oxygen delivery is associated with an increased risk of severe postoperative complications after elective open repair of AAA. The value of preoperative optimization of oxygen delivery should be evaluated in this patient population.

Preoperative risk stratification in patients undergoing elective infrarenal aortic aneurysm surgery: evaluation of five risk scoring methods.

OBJECTIVE: To evaluate five risk scoring methods in predicting the immediate postoperative outcome after elective open repair of abdominal aortic aneurysm (AAA). DESIGN: Retrospective evaluation of the Eagle score, Glasgow aneurysm score, Leiden score, modified Leiden score and Vanzetto score in a consecutive series of patients. PATIENTS: Two hundred and eighty-six consecutive patients undergoing elective infrarenal aortic aneurysm repair. RESULTS: Nine patients (3.1%) died in hospital and another 35 (12%) experienced severe postoperative complications. For the Glasgow aneurysm score, Leiden score, modified Leiden score and Vanzetto score receiver operating characteristics (ROC) curve analysis for prediction of in-hospital mortality showed area under the curve (AUC) of 0.749 (p=0.01), 0.777 (p=0.008), 0.788 (p=0.006) and 0.794 (p=0.005), respectively. The Eagle risk score was less accurate for predicting in-hospital mortality. The risk-scoring systems did not perform well in predicting post-operative complications, but multivariate analysis showed that the modified Leiden score was an independent predictor of postoperative complications. CONCLUSION: All scoring systems predict, with reasonable accuracy, the risk of in-hospital death in patients undergoing elective open repair of AAA, whereas the accuracy in predicting severe postoperative complications is less.

Increased medial TUNEL-positive staining associated with apoptotic bodies is linked to smooth muscle cell diminution during evolution of abdominal aortic aneurysms.

Apoptosis has recently been identified as an important process in large vessel structural integrity. We examined whether the size of the abdominal aortic aneurysm might be associated with programmed cell death. We performed in situ labeling of the 3' ends of DNA fragments by apoptosis-associated endonucleases in 20 aneurysms, 10 controls with aortoiliac occlusive disease, and 4 controls with healthy aortas. Antibodies against a-smooth muscle actin were used to quantify smooth muscle cell alterations in the medial layer. Inflammatory cell characterization was made by using four monoclonal mouse antibodies (UCHL1, L26, PG-M1, and KP1). The results confirm the assumption that an apoptotic process may be of consequence for the loss of medial smooth muscle cells in the early evolution of an abdominal aortic aneurysm process.

Effects of diclofenac in the prevention of pericardial effusion after coronary artery bypass surgery. A prospective, randomized study.

BACKGROUND: It is suggested that pericardial effusions after cardiac surgery can be managed with non-steroid anti-inflammatory drugs, but the efficacy of this therapy is not well established. This study was planned to evaluate the efficacy of the prophylactic use of diclofenac in the prevention of pericardial effusion after coronary artery bypass surgery. METHODS: In a prospective, randomized study, diclofenac sodium 50 mg was administered orally every 8 hours to 22 patients in the postoperative period. The control group consisted of 19 patients who were not given postoperatively either steroids or non-steroid anti-inflammatory drugs. RESULTS: Twelve patients of the diclofenac-treated group (54.5%) and 7 of the control group (36.8%) experienced supraventricular arrhythmias postoperatively. There was no statistically significant difference in the size of postoperative pericardial effusion as well as in the occurrence of pleural effusion in both groups. However, there was a higher rate of significant pericardial effusion (grade I-III) in the control group as compared with the diclofenac-treated group (52.6% vs 31.8%, p=ns). Based on chest X-ray findings, patients in the control group had higher incidence of pleural effusion either alone (42.1% vs 22.7%, p=ns) or combined with pericardial effusion (21.0% vs 13.6%, p=ns). Patients who received diclofenac had lower median C-reactive protein concentration (76.0+/-45.2 mg/L) than the patients of the control group (99.6+/-47.8 mg/L), (p=ns). CONCLUSIONS: The results of the present study suggest that diclofenac, even if without a striking effect, may lessen the degree of inflammatory reaction after cardiac surgery and may be useful in the prevention and in the management of early pericardial effusion after cardiac surgery.

Increased amount of type III pN-collagen in AAA when compared with AOD.

OBJECTIVE: the extent of the processing of type III procollagen to type III collagen was determined in nine human abdominal aortic aneurysms (AAA), and compared with ten samples of aortoiliac occlusive disease (AOD). METHODS: the aminoterminal propeptide (PIIINP) and telopeptide (IIINTP) of type III procollagen and collagen, respectively, were immunologically measured in the soluble and insoluble fractions of the extracellular matrix. The assay for PIIINP in the insoluble matrix was further validated. RESULTS: the insoluble matrices of AAAs contained at least 12 times more incompletely processed type III pN-collagen than AOD specimens (0.74% and 0.061%, respectively). Also, the soluble extracts of AAAs tended to contain more non-processed type III pN-collagen than free, properly cleaved aminoterminal propeptide. CONCLUSIONS: the larger amount of type III pN-collagen suggests an alteration in the metabolism of type III collagen in AAAs. This may partially explain the decreased tensile strength of the aortic tissue.

Use of doxycycline to decrease the growth rate of abdominal aortic aneurysms: a randomized, double-blind, placebo-controlled pilot study.

OBJECTIVE: Eradication of Chlamydia pneumoniae infection and inhibition of elastolytic matrix metalloproteinases with doxycycline have been suggested to reduce the growth rates of small abdominal aortic aneurysms (AAA). We designed a study to investigate the efficacy of doxycycline in reducing the expansion of small AAAs. SUBJECTS AND METHODS: This was a prospective, double-blind, randomized, placebo-controlled study that was set in a university referral hospital. The study group consisted of 32 of 34 initially eligible patients who had an AAA diameter perpendicular to the aortic axis of 30 mm or more in size or a ratio of infrarenal to suprarenal aortic diameter of 1.2 or more and a diameter less than 55 mm. Patients were randomly assigned to receive either doxycycline (150 mg daily) or placebo during a 3-month period and underwent ultrasound surveillance during an 18-month period. Outcome measures included aneurysm expansion rates, the number of patients who had AAA rupture or repair, C pneumoniae antibody titers, and serum concentrations of C-reactive protein. RESULTS: The aneurysm expansion rate in the doxycycline group was significantly lower than that in the placebo group during the 6- to 12-month (P = .01) and the 12- to 18-month periods (P =.01). Five patients (41%) in the placebo group and 1 patient (7%) in the doxycycline group had an overall expansion of the aneurysm of 5 mm or more during the 18-month follow-up. Among the placebo group patients, a higher expansion rate was observed in those with enhanced C pneumoniae immunoglobulin G antibody titers (> 128) than in those with lower titers (P = .03). Doxycycline treatment had no clear effect on antibody titers. However, at 6-month follow-up, C-reactive protein levels in the doxycycline group were significantly lower than the baseline levels (P = .01). CONCLUSIONS: The results of this small pilot study suggest that doxycycline may favorably alter the outcome of patients with small AAA. However, because of the small size of this randomized study and of the potentially confounding effect of pretreatment risk factors, doxycycline-based treatment cannot be justified only on the ground of the current results. Because of the high prevalence of this disorder and its clinical, social, and economic relevance, a multicenter study should be performed to further investigate whether there is any place for medical treatment of small AAAs.

Expression of MMP2, MMP9, MT1-MMP, TIMP1, and TIMP2 mRNA in valvular lesions of the heart.

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play an important role in several diseases. This study was undertaken to investigate the mRNA synthesis of MMP2, MMP9, membrane-type 1 (MT1)-MMP, and matrix metalloproteinase inhibitors TIMP1 and TIMP2 by in situ hybridization in a set of heart mitral and aortic valves operatively removed due to degenerative or inflammatory valvular diseases. The material consisted of 21 valves, eight with endocarditis and 13 with a degenerative valvular disease. The samples were studied by in situ hybridization with specific probes for MMP2, MMP9, MT1-MMP, TIMP1, and TIMP2. Synthesis of MMP2 mRNA was found in seven valves, five with endocarditis and two with degenerative valvular disease. Signals for MMP9 mRNA were found in two cases with endocarditis and five cases with degenerative valvular disease. No signal for MT1-MMP mRNA was found in the lesions. TIMP1 mRNA, on the other hand, was found in 17 cases, both endocarditis and degenerative valvular disease. TIMP2 mRNA was found in three cases of endocarditis. The signals for MMP2, MMP9, TIMP1, and TIMP2 mRNA were localized in endothelial cells and in fibroblast-like cells expressing alpha-smooth muscle actin, thus showing myofibroblast-type differentiation. The results show that matrix metalloproteinases MMP2 and MMP9, and matrix metalloproteinase inhibitors TIMP1 and TIMP2 mRNAs are synthesized in diseased valves and suggest that they may contribute to matrix remodelling in valvular disease.

Increased amount of type III pN-collagen in human abdominal aortic aneurysms: evidence for impaired type III collagen fibrillogenesis.

PURPOSE: This study aimed to characterize the distribution of structural domains of type I and III collagens in the wall of abdominal aortic aneurysms (AAAs), by the use of undilated atherosclerotic aortas (aortoiliac occlusive disease [AOD]) and healthy abdominal aortas as controls. METHODS: Immunohistochemical staining was applied with antibodies for the aminoterminal propeptides of type I (PINP) and type III (PIIINP) procollagens, which represent newly synthesized type I and III pN-collagens. In addition, an antibody against the aminoterminal telopeptide of type III collagen (IIINTP) was used as a means of detecting maturely cross-linked type III collagen fibrils. RESULTS: The newly synthesized type III procollagen detected by means of PIIINP staining was concentrated in the media in aneurysmal aortas, whereas type I pN-collagen was localized in the intima in both AAAs and AODs. The healthy aortas showed no immunoreactivity for either PIIINP or PINP. The cross-linked type III collagen, detected by means of IIINTP staining, stained transmurally in all study groups, but appeared more abundant in the media in AAAs. CONCLUSION: Our results strongly suggest that the metabolism of type III collagen is enhanced in AAAs. Intensive type III pN-collagen staining was present mainly in the media layer in AAAs, suggesting a role of type III collagen in aneurysm formation, whereas type I pN-collagen was present in the intima in both AAAs and AODs, suggesting that type I collagen synthesis is a fibroproliferative response related to the atherosclerotic process. The increased type III pN-collagen in AAAs may result in impaired fibril formation and, thus, in decreased tensile strength of aneurysmal tissue.

Internal Mammary Artery Harvesting and Antibiotic Concentrations in Sternal Bone During Coronary Artery Bypass.

The concentrations of two antibiotics (vancomycin and cefuroxime) in sternal bone during coronary artery bypass surgery were analyzed to examine whether antibiotic penetration is impaired after dissection and harvesting of the left internal mammary artery for grafting. Bone samples (250 mg of cancellous sternal bone from both halves of the dissected manubrium) were obtained at the time of sternal opening and closure. Twenty patients undergoing primary coronary artery bypass grafting with the left internal mammary artery were randomized so that ten received 1.5 g of vancomycin over 180 minutes and ten 3 g of cefuroxime over 30 minutes beginning at the time of induction of anesthesia. Serum samples were collected at the same time as the bone samples and 12 h after the start of the infusions. There was a slight difference in vancomycin concentration between two sternal halves after IMA dissection at the time of sternal closure (median difference, 0.2 µg/g, and 95% confidence interval, -0.55 to 0.1). This difference was not statistically significant at the P = 0.05 level (P = 0.15, Wilcoxon matched-pair test). The cefuroxime concentration of the bone was below the detection limit (7.6 to 9.2 µg/g) in all ten patients at the time of sternal closure. Harvesting the internal mammary artery for coronary artery bypass grafting may influence the concentration of vancomycin in the manubrium of the sternum.

Complete processing of type III collagen in atherosclerotic plaques.

The extent of processing of type III collagen is assessed, and the proportions of type I and III collagens are estimated in atherosclerotic plaques obtained from the carotid artery, common femoral artery, and aorta. The fraction of type III collagen that had retained its amino-terminal propeptide (pN-collagen) was 42% in the soluble extract but only 0.0081% in the insoluble residue. Taken together, only 0.011% of the type III collagen in whole plaques was in the form of type III pN-collagen. Together with the small amounts of the free propeptides of type I procollagen, this finding indicates a low rate of collagen turnover. The amounts of solubilized telopeptides of type I and III collagens were measured, after heat denaturation and trypsin digestion of the collagenous helix, by specific immunoassays for the corresponding trypsin-generated antigens. The mean proportion of type III collagen was 61% (95% confidence interval, 58% to 65%) in the carotid and femoral artery plaques and 56% (95% confidence interval, 44% to 68%) in the aortic specimens. The completely processed and cross-linked type III collagen seems to be the major collagen type in atherosclerotic plaques.

Multiple endocrine neoplastic-associated thymic carcinoid tumour in close relatives: octreotide scan as a new diagnostic and follow-up modality. Two case reports.

Thymic carcinoid tumours constitute less than 1% of all carcinoids, and differ markedly from true thymomas in natural history, morphology, prognosis and therapeutic options. New clinical and diagnostic modalities are described in two brothers with thymic carcinoid associated with multiple endocrine neoplasia syndrome. Octreotide scintigraphy proved useful for diagnosis and follow-up, and somatostatin receptor positivity may provide new prospects for treatment of non-resectable or recurrent tumour.

Computed tomographic evaluation of retrosternal adhesions after pericardial substitution.

BACKGROUND: Reoperative median sternotomy can result in cardiac injury and serious bleeding, with the rate ranging from 2% to 6%. Closure of the native pericardium can maintain a preventing plane of cleavage. In patients in whom primary pericardial closure is not possible, several substitutes have been tried with variable results. We conducted a prospective study to evaluate the clinical feasibility of polytetrafluoroethylene and polyglycolic acid patches as pericardial substitutes, using computed tomography for imaging the postoperative state of the retrosternal space. METHODS: The basic population comprised 540 patients who were scheduled for coronary artery bypass grafting, and 52 of them who met the research criteria were chosen for computed tomographic evaluation after 5 years after the primary operation. RESULTS: As a substitute, polytetrafluoroethylene seemed to be less adhesive to the posterior surface of the sternum. Total adhesion scores were also statistically significant (p < 0.001) to the advantage of polytetrafluoroethylene over polyglycolic acid as a pericardial substitute. CONCLUSIONS: Polytetrafluoroethylene membrane seems to be capable of minimizing retrosternal adhesion formation and thus it may protect the heart during subsequent reoperative sternotomy.

Chronic inflammation and elastin degradation in abdominal aortic aneurysm disease: an immunohistochemical and electron microscopic study.

OBJECTIVES: To investigate (i) elastin degradation and the possible association between proteolysis and inflammation in abdominal aortic aneurysm disease (AAA), and (ii) the presence of cytomegalovirus (CMV) infection in the walls of AAA. MATERIALS: Specimens from 12 infrarenal AAAs, eight aortas with occlusive disease (AOD) and two normal aortas were studied by conventional light microscopy, immunohistochemistry using a monoclonal anti-elastin antibody BA-4 and anti-CMV antibody and transmission electron microscopy (TEM). MAIN RESULTS: In AAA the decrease in elastin immunoreactivity and the presence of elastin degradation was associated with increased mononuclear inflammatory cell infiltrates (p = 0.004 and p = 0.00002, respectively). The CMV immunostainings of the normal aortic wall and all the AAA and AOD samples were negative, nor could any CMV particles be demonstrated by TEM. CONCLUSIONS: The chronic inflammation and degradation of elastin in AAA suggests a possible immune-mediated mechanism. The inflammation may be induced by the chemotactic properties of elastin-derived peptides.

Pericardial closure with polytetrafluoroethylene surgical membrane or biodegradable polyglycolic acid mesh after coronary artery bypass surgery--a baseline report.

BACKGROUND AND AIMS: Complete and tight closure of the native pericardium may kink or even occlude bypass grafts after coronary artery bypass grafting (CABG) and therefore the feasibility of tight closure has been debated. The growing number of reoperations has raised the question how to reduce the risk of damage of the right ventricle and patent grafts. We are performing a prospective randomized trial aiming to evaluate the feasibility of polytetrafluoroethylene (PTFE) surgical membrane and biodegradable polygycolic acid (PGA) mesh as pericardial substitutes for closure purposes in patients undergoing primary isolated CABG surgery. MATERIAL AND METHODS: The series comprises 540 patients who underwent a primary isolated CABG procedure at the Oulu University Hospital from October 1989 to May 1994. RESULTS AND CONCLUSIONS: The baseline results suggest that the PTFE and PGA materials seem to be similar despite the subtle early expression of tamponade related to the PTFE membrane after postoperative bleeding.

Angiogenesis is associated with mononuclear inflammatory cells in abdominal aortic aneurysms.

BACKGROUND AND AIMS: To evaluate the extent of neovascularisation in abdominal aortic aneurysms, specimens from the aneurysm walls of 17 consecutive patients (14 men, mean age 69 years, range 59 to 79 years) were studied and compared with specimens from patients with aortoiliac occlusive disease (n = 8, five men, mean age 53 years; range 40 to 71 years). Routine histology was performed after haematoxylin and eosin, Verhoeff's elastic and periodic acid-Schiff stainings. For immunophenotypic analysis of inflammatory cells four monoclonal mouse antibodies (UCHL1, L26, PG-M1 and KP1) were used. RESULTS: The histological sections through the walls of the AAAs showed extensive destruction of elastin and variable inflammation. Dense neovascularisation was seen throughout the aortic wall in the AAA cases compared to a mild angiogenetic response seen only occasionally in the AODs. CONCLUSIONS: Angiogenesis may play a significant role in the AAA process by recruiting and carrying a macrophage-rich infiltrate to the aortic wall.

Options for the management of poststernotomy mediastinitis.

The management of 27 consecutive deep sternotomy wound infections is reviewed. In 22 cases the initial treatment was debridement, sternal refixation and dilute antibiotic irrigation via multiple irrigation-suction catheters. In the nine cases (41%) in which these measures failed, more extensive sternal and costal cartilage debridement and closure with a muscle flap were performed. Five cases were initially managed with major reconstructive surgery. For reconstruction, a bilateral pectoralis major myocutaneous flap was used alone in eight cases, while in six the flap was insufficient to obliterate the whole poststernectomy space, and was supplemented with rectus abdominis muscle. Early mediastinitis can be effectively treated with thorough wound debridement and mediastinal irrigation, but if there is a two-week delay from the initial sternotomy to manifestation of infection, radical debridement with muscle flap closure should be seriously considered.