Mediastinitis after coronary artery bypass grafting increases the incidence of left internal mammary artery obstruction.

Mediastinitis after coronary artery bypass grafting (CABG) gives a longstanding chronic inflammation and has a detrimental negative effect on long-term survival. For this reason, we aimed to study the effect of mediastinitis on graft patency after CABG. The epidemiologic design was of an exposed (mediastinitis, n = 41) versus non-exposed (non-mediastinitis, controls, n = 41) cohort with two endpoints: (i) obstruction of saphenous vein grafts (SVG) and (ii) obstruction of the internal mammary artery (IMA) grafts. The graft patency was evaluated with coronary CT-angiography examination at a median follow-up of 2·7 years. The number of occluded SVG in the mediastinitis group was 18·9% versus 15·5% in the control group. Using generalized estimating equations model with exchangeable matrix, and confounding effect of ischaemic time and patients age, we found no significant association between presence of mediastinitis and SVG obstruction [rate ratio (RR) = 0·96, 95% CI (0·52-2·67), P = 0·697]. The number of occluded IMA grafts was 10·5% in the mediastinitis group and 2·4% in the control group. Using the Poisson regression model, we estimated RR = 5·48, 95% CI (1·43-21·0) and P = 0·013. There was a significant association between mediastinitis and IMA graft obstruction, when controlling for the confounding effect of ischaemic time, body mass index, presence of diabetes mellitus and the number of diseased vessels. Presence of mediastinitis increases the risk of IMA graft obstruction. This may confirm the importance of inflammation as a major contributor to the pathogenesis of atherosclerosis and explain the negative effect of mediastinitis on a long-term survival.

In vitro evaluation of PHISIO-coated sets for pediatric cardiac surgery.

OBJECTIVES: Phosphorylcholine coated cardiopulmonary bypass (CPB) circuits for children have been available for some years, but conflicting results regarding the inflammatory response have been reported. Accordingly, we aimed to investigate the effect of phosphorylcholine coating on the inflammatory response. DESIGN: Ten coated and nine uncoated pediatric CPB sets were tested in an in vitro CPB circuit model. The inflammatory response was assessed by serial assays of hemoglobin, hematocrit, leukocyte counts, platelet counts, activation of the complement system, activation of platelets measured as beta-thromboglobulin, activation of neutrophils measured as myeloperoxidase, activation of coagulation measured as prothrombin fragments 1+2, assessment of hemolysis measured as lactate dehydrogenase, and a panel of seven cytokines. Samples were obtained at baseline and after 15, 30, 60 and 120 minutes. RESULTS: There were no significant differences between the phosphorylcholine coated circuits and the uncoated circuits for any of the parameters during the observation period, although a potentially beneficial effect on platelets could not be ruled out. CONCLUSIONS: Phosphorylcholine coating of CPB equipment did not exert any beneficial effect on the inflammatory markers monitored.

Twenty-five-year experience with the Medtronic-Hall valve prosthesis in the aortic position: a follow-up cohort study of 816 consecutive patients.

BACKGROUND: The Medtronic-Hall valve was developed and for the first time implanted in Oslo, Norway, in 1977. A total of 1104 patients received this valve at Rikshospitalet from 1977 to 1987. In the present study, we followed up on all 816 patients undergoing aortic valve replacement over a 25-year period. METHODS AND RESULTS: This is a retrospective cohort analysis of 816 consecutive patients undergoing aortic valve replacement with the Medtronic-Hall valve at Rikshospitalet, Oslo, Norway, from 1977 to 1987. All patients were contacted by means of questionnaires or telephone. Data were checked against hospital databases and medical records. Date of death was verified by the Norwegian civil registry. Follow-up was 99.6% complete. Survival analysis included operative deaths as well as late deaths. Survival at 25 years was 24.9%. No mechanical failures were found. Valve thrombosis was seen in 4 patients, in 1 case combined with pannus formation. Small valves (20 mm to 21 mm) were associated with reduced survival; however, when controlled for the confounding effects of age and gender, valve size did not remain a significant risk factor. Patient-related factors were important: Older age, female gender, and the need for concomitant coronary artery bypass surgery significantly reduced survival, whereas surgery of the ascending aorta did not. Linearized rates of thromboembolic complications, warfarin-related bleeding, and endocarditis were 1.5%, 0.7%, and 0.16%/patient-year, respectively. At follow-up, 79% of the patients were in New York Heart Association classes I to II. CONCLUSIONS: This study confirms the excellent long-term outcome for patients with Medtronic-Hall valves in the aortic position.

Solid cerebral microemboli and cerebrovascular symptoms in patients with prosthetic heart valves.

BACKGROUND AND PURPOSE: Although cerebral microemboli are often detected by transcranial Doppler ultrasonography in mechanical heart valve patients, the clinical significance of such microemboli is unclear. The aim of this study was to determine the frequency and composition of cerebral microemboli in a prosthetic heart valve population and to correlate these findings to cerebrovascular symptoms, blood inflammation, and coagulation parameters. METHODS: Seventy-six consecutive patients with a total of 81 prosthetic (54 mechanical, 27 biologic) heart valves were monitored for cerebral microemboli by multifrequency transcranial Doppler ultrasonography 1 year after valve replacement. Cerebrovascular events in the first year were recorded by a neurologist. Inflammation and coagulation markers were measured by immunoassays. RESULTS: Microemboli were detected in mechanical heart valve patients only (28 patients, 56%). Twelve percent were solid, occurring in 17 (34%) of the mechanical heart valve population. The presence of solid cerebral microemboli was the only variable that was associated with cerebrovascular symptoms after a final regression analysis (P=0.026). The plasma monocyte chemotactic protein-1 level was raised in patients with solid microemboli (P=0.014). CONCLUSIONS: Solid cerebral microemboli were detected by multifrequency transcranial Doppler ultrasonography in 35% of a mechanical heart valve population, and the frequency was higher in patients who experienced cerebrovascular events during the first year after valve replacement. The results suggest that the detection of solid cerebral microemboli may be helpful in predicting the risk of ischemic stroke in mechanical heart valve patients.

The worldwide mid-term experience with the Medtronic ADVANTAGE bileaflet mechanical heart valve.

BACKGROUND AND AIM OF THE STUDY: A total of 639 patients (479 men, 160 women; mean age 60 +/- 10 years) underwent isolated aortic valve replacement (AVR) between 25 November 1999 and 20 October 2003, using the Medtronic ADVANTAGE bileaflet mechanical heart valve. The study aim was to quantify the clinical performance of a valve with two design modifications: (i) an enlarged central orifice intended to improve blood flow characteristics; and (ii) an asymmetric butterfly pivot recess with expanded outflow component designed to enhance the washing of blood flow through the pivot region. METHODS: Patients were enrolled at 21 centers located in Europe, Canada, Australia, and the USA. The study was conducted under the authority of regional ethics committees, as well as the respective national regulatory agencies. All centers adhered to a common protocol. RESULTS: The total follow up was 1,215.9 patient-years. The average systolic mean pressure gradient across the prosthesis was < 10 mmHg. The mean left ventricular mass index decreased by 22.87 g/m2 (13% reduction) over 12 months. The numbers of valve-related intraoperative, early (< or = 30 days or prior to discharge) and late (> or = 31 days) deaths were 0, 10 and 19, respectively. After one year and four years of follow up, 99.3% (n = 560) and 100% of patients (n = 37), respectively, were in NYHA class I or II. CONCLUSION: The evolutionary bileaflet design of the ADVANTAGE valve achieved the desired clinical functionality and performance.

[A 60-year-old woman with asthenia and dyspnoea]. / En 60 år gammel kvinne med asteni og dyspné.

Coronary artery aneurysms are uncommon and the prevalence in patients undergoing coronary artery angiography is 1.5-4.9%. The most common cause of coronary artery aneurysm is arteriosclerosis, followed by Kawasaki disease, periarteritis nodosa, systemic lupus erythematosus, syphilis, rheumatic fever, congenital heart disease and trauma. Most coronary aneurysms remain asymptomatic. Patients may present symptoms of angina or myocardial infarction due to thrombosis within the aneurysm. This would lead to occlusion of the coronary artery or to distal thromboembolisms. There is no consensus on how to manage coronary artery aneurysms. Medical therapies include aspirin as well as warfarin. Surgery may be performed in patients with a large aneurysm, i.e. when the risk of rupture or thrombosis is high. We present a 60-year-old female patient with symptoms of a transient ischaemic attack followed by a period of fever, nausea, vomiting and ecchymoses on the lower extremity. Transthoracic and transoesophageal echocardiography was suggestive of a tumour located at the basis of the lateral wall of the right atrium. Heart surgery revealed, however, a large right coronary aneurysm and an atrial septum defect of the secundum type.

[A 54-year old man with severe circulatory collapse]. / En 54 år gammel mann med alvorlig sirkulasjonssvikt.

The frequent use of mechanical circulatory assistive devices in the treatment of patients in cardiogenic shock increases the need for advanced air and ground transport services. In this article we describe a critically ill patient with acute myocardial infarction. He was treated with intraaortic balloon pump at the local hospital before transfer to a university hospital by air. Close cooperation between the university hospital, the Norwegian Air Ambulance and the Norwegian aviation authorities has facilitated this service.

Intraoperative and intermediate-term angiographic results of coronary artery bypass surgery with Symmetry proximal anastomotic device.

OBJECTIVE: The objective of this study was to investigate the patency in saphenous vein coronary bypass grafts in which the proximal anastomoses were performed with automatic connector devices or with a traditional suture technique. METHODS: Forty-six patients underwent coronary artery bypass grafting without cardiopulmonary bypass by using one thoracic graft and one or more saphenous vein grafts. Grafts were attached to the aorta with a Symmetry connector (St Jude Medical, Inc, St Paul, Minn) in 23 patients, and partial occlusion of the aorta and sutured anastomoses were used in 23 other patients. Grafts were studied intraoperatively with transit time flowmetry and angiography and revised if necessary. Angiography was repeated after 3 to 5 months. RESULTS: Intraoperative graft patency did not differ between the 2 groups. Follow-up angiography demonstrated excellent thoracic graft patency. Vein graft patency decreased to 50% in the Symmetry group, whereas it was 90% in the suture group ( P = .01). Twenty-five percent of the Symmetry grafts had significant stenosis in the connector. CONCLUSION: Saphenous vein grafts anastomosed to aorta with the Symmetry proximal connector have low intermediate patency compared with those with traditionally sutured anastomoses. We do not recommend the routine use of this device in coronary artery bypass operations.

Repair of left ventricular aneurysm: surgical risk and long-term survival.

BACKGROUND: The aim of the study was to identify predictors for survival after repair of postinfarction left ventricular aneurysm. METHODS: We retrospectively reviewed the records of 149 patients who had an operation for postinfarction left ventricular aneurysm between 1989 and 2001. The following variables were recorded: preoperative clinical, angiographic, and echocardiographic findings and operative procedures. Outcomes were early mortality (<30 days) and long-term survival. Risk factors were pinpointed using t test or Mann-Whitney test, contingency tables, and survival curves. Independent risk factors were identified by logistic regression and Cox regression methods. Mean follow-up was 5.8 years (range, 0 to 13.8 years). RESULTS: The early mortality (<30 days) rate was 8.7% altogether, and the 5-year cumulative survival rate was 77%. Advanced age, history of ventricular arrhythmia, three-vessel disease, and linear repair technique were independent risk factors for early and total mortality. Poor left ventricular function predicted reduced long-term survival but did not increase surgical risk. Survival was not affected by gender, diabetes, type and severity of symptoms, anterior or posterior aneurysm, revascularization of the left anterior descending artery, or number of distal anastomoses. CONCLUSIONS: Postinfarction left ventricular aneurysm can be repaired with acceptable surgical risk and long-term survival. Survival is reduced in cases with advanced age, history of ventricular arrhythmia, three-vessel disease, poor left ventricular function, and linear repair of the aneurysm.

Complement activation and cytokine and chemokines release during mediastinitis.

BACKGROUND: Mediastinitis after open heart operation is an infrequent, but life-threatening complication with a reported incidence rate between 1% and 4%. Hospital mortality is estimated at 10% to 35%. The aim of the present work was to study the systemic inflammatory reaction as judged by complement activation and cytokine and chemokines release in patients with mediastinitis after open heart operation. METHODS: Seven patients with clinical signs of mediastinitis were included. Three patients had undergone coronary artery bypass grafting, whereas 4 patients had combined coronary artery bypass grafting, valve replacement, or valvuloplasty. Blood samples were drawn before induction of anesthesia and at the time of reoperation, and thereafter daily during the hospital stay. Controls comprised similar patients with an uneventful postoperative course. RESULTS: The terminal SC5b-9 complement complex concentration in the mediastinitis patients was substantially higher compared with the controls (p < 0.001), and the terminal SC5b-9 complement complex values showed no overlap between the two groups. Interleukin-8, stromal cell-derived factor-1alpha and IL-6 concentrations were also significantly higher in the mediastinitis group than in the control group (p < 0.001), but with considerable overlap between the groups. Interleukin-1beta, interleukin-10, and monocyte chemoattractant protein-1 concentrations were slightly higher in the mediastinitis group, and no differences were seen for the tumor necrosis factor-alpha. CONCLUSIONS: During mediastinitis, the complement is activated and the cytokines and chemokines, interleukin-6, interleukin-8, and stromal cell-derived factor-1alpha are released. These proteins may be involved in the pathogenesis of this complication. Terminal SC5b-9 complement complex may be an indicator to discriminate mediastinitis patients from those with uneventful course.

Sternal wound closure in patients undergoing open-heart surgery: a prospective randomized study comparing intracutaneous and zipper techniques.

OBJECTIVE: A prospective, randomized study was undertaken to compare a non-invasive surgical zipper to intracutaneous suture closure in open-heart surgery with respect to postoperative wound infection rate and cosmetic results. METHODS: A total number of 300 patients were included in the study, of which 150 had their skin wound closed with zipper and 150 with intracutaneous suture. The end-points were superficial and deep sternal wound infections within 6 weeks postoperatively. RESULTS: The incidence of total infection after 6 weeks was equal in the two groups (6.7 vs. 6.7%) (P=0.94). The superficial infection rate was 5.3% in the zipper group vs. 6.0% in the intracutaneous, and the deep infection rate was 1.4% in the zipper group and 0.7% in the intracutaneous. There was no statistically significant difference between the groups. Only the cosmetic result differed. On a visual scale from 1 (poorest) to 10 (best), an average score of 8.2 was obtained in the intracutaneous group versus 8.9 in the zipper group (P<0.01). CONCLUSION: The wound infection rate was equal for the intracutaneous group compared with the zipper group; however, the cosmetic result was judged better by the patients in the zipper group.

Detection of left ventricular dysfunction by global longitudinal systolic strain in patients with chronic aortic regurgitation.

BACKGROUND: The purpose of this study was to investigate whether global longitudinal strain measured by two-dimensional speckle tracking echocardiography could detect incipient myocardial dysfunction in patients with chronic aortic regurgitation (AR). Disclosing left ventricular (LV) dysfunction is of decisive importance for optimal timing of surgery but challenging because of the altered loading conditions. METHODS: Forty-seven patients referred for aortic valve replacement because of chronic AR were studied, along with 31 healthy controls. Myocardial deformation as determined by longitudinal, circumferential, and radial strain was calculated using two-dimensional speckle-tracking echocardiography technique, in addition to LV volumes, dimensions, and ejection fraction. Strain values were normalized to end-diastolic volume to correct for the volume dependency of deformation. RESULTS: Global systolic longitudinal strain was significantly lower in patients with AR before surgery compared with the healthy controls (-17.5 ± 3.1% vs -22.1 ± 1.8%, P < .01), while global circumferential strain and LV ejection fraction did not differ (-21.7 ± 3.4% vs -22.6 ± 2.5%, P = .22 and 59 ± 5% vs 59 ± 6%, P = .59, respectively). However, differences between patients and controls were evident for both longitudinal and circumferential strain when normalized to end-diastolic volume (-0.09 ± 0.04 vs -0.23 ± 0.08, P < .01, and -0.11 ± 0.05 vs -0.24 ± 0.08, P < .01, respectively). In contrast to their absolute values, both normalized variables demonstrated improvement in myocardial shortening after valve replacement (P < .01). CONCLUSIONS: The study demonstrated reduced global longitudinal strain in patients with chronic AR with preserved LV ejection fractions. Global longitudinal strain might therefore disclose incipient myocardial dysfunction with a consequent potential for improved timing of aortic valve surgery.

The Scandinavian multicenter hemodynamic evaluation of the SJM Regent aortic valve.

BACKGROUND: 112 patients who received small and medium sized St. Jude Regent heart valves (19-25 mm) at 7 Scandinavian centers were studied between January 2003 and February 2005 to obtain non-invasive data regarding the hemodynamic performance at rest and during Dobutamine stress echocardiography (DSE) testing one year after surgery. MATERIAL AND METHODS: 46 woman and 66 men, aged 61.8 ± 9.7 (18-75) years, were operated on for aortic regurgitation (17), stenosis (65), or mixed dysfunction (30). Valve sizes were 19 mm (6), 21 mm (33), 23 mm (41), 25 mm (30). Two patients receiving size 27 valves were excluded from the hemodynamic evaluation. Pledgets were used in 100 patients, everted mattress in 66 and simple interrupted sutures in 21. Valve orientation varied and was dependent on the surgeons' choice. 34 patients (30.4%) underwent concomitant coronary artery surgery. RESULTS: There were two early deaths (1.8%) and three late deaths, one because of pancreatic cancer. Late events during follow-up were: non structural dysfunction (1), bleeding (2), thromboembolism (2). At one year follow up 93% of the patients were in NYHA classes 1-2 versus 47.8% preoperatively. Dobutamine stress echocardiography (DSE) was performed in a total of 66 and maximal peak stress was reached in 61 patients. During DSE testing, the following statistically significant changes took place: Heart rate increased by 73.0%, cardiac output by 85.5%, left ventriclular ejection fraction by 19.6%, and maximal mean prosthetic transvalvular gradient by 133.8%, whereas the effective orifice area index did not change. Left ventricular mass fell during one year from 215 ± 63 to 197 ± 62 g (p < 0.05). CONCLUSION: The Dobutamine test induces a substantial stress, well suitable for echocardiographic assessment of prosthesis valve function and can be performed in the majority of the patients. The changes in pressure gradients add to the hemodynamic characteristics of the various valve sizes. In our patients the St. Jude Regent valve performed satisfactory at rest and under pharmacological stress situation.

Mediastinitis after coronary artery bypass grafting risk factors and long-term survival.

BACKGROUND: Mediastinitis is a severe complication of coronary artery bypass grafting. The aim of the present study was to determine incidence of mediastinitis, its risk factors, and its effect on early and long-term survival. METHODS: The study has a dual design, a case-control, and a retrospective cohort, using a source population of 18,532 consecutive patients who underwent coronary artery bypass grafting from January 1989 to December 2000. The closing date was February 1, 2008. Median follow-up was 10.3 (range 8.1 to 18.9) years. Patients with mediastinitis were compared with a random control group without mediastinitis issued from the same source population in a ratio 1:4. The crude effect of mediastinitis was estimated using rate ratio and 95% confidence limits. Adjustment for multiconfounders was done with the Cox model. A logistic model was used to pinpoint risk factors of mediastinitis. Calibration and discrimination of a prognostic model was done. RESULTS: One hundred seven patients (0.6%) developed mediastinitis. Diagnosis was made 12 (9 to 19) days postoperatively. Independent risk factors of mediastinitis using the logistic model were advanced age, male gender, left main stenosis, body mass index 30 kg/m(2) or greater, chronic obstructive pulmonary disease, diabetes, and increased amount of blood transfusion. There was no increased risk of early mortality (odds ratio = 0.58; 95% confidence interval 0.13 to 2.61) (p = 0.48) but there was increased risk of morbidity (intraaortic balloon pump, ventricular and supraventricular arrhythmia, stroke, inotrope, and myocardial infarction). Follow-up had a median observation time of 10.3 years. Survival for patients with mediastinitis was 49.5 +/- 5.0% versus 71.0 +/- 2.2% for controls (p < 0.01). Analysis of specific death causes documented that cardiac deaths were significantly more frequent in mediastinitis patients than in control patients. When controlling for the confounding effect of the other variables (age, cardiopulmonary bypass time, body mass index, chronic obstructive pulmonary disease), the hazard ratio associated with mediastinitis on long-term mortality was 1.59, 95% confidence limits (1.16 and 2.70) (p = 0.003). CONCLUSIONS: The incidence of mediastinitis in 18,532 patients undergoing coronary artery bypass grafting surgery was low. The major preventable risk factor of mediastinitis was amount of blood transfusion. Mediastinitis had an excess risk of early morbidity and was associated with a significant reduced long-term survival. Most deaths were considered to be cardiac.

Cost of extracorporeal membrane oxygenation: evidence from the Rikshospitalet University Hospital, Oslo, Norway.

OBJECTIVE: The main objective is to describe and analyse hospital costs of the extracorporeal membrane oxygenation (ECMO) procedure. STUDY SAMPLE AND METHODOLOGY: Between January and December 2007, 14 ECMO patients were consecutively included in the study. Costs at the patient level were registered prospectively, while overhead costs were registered retrospectively. Patient costs were obtained from patient records and time-motion studies and included personnel resources, diagnostic and laboratory tests, radiology and operating room procedures, medication and blood products. Overhead costs were allocated to clinical departments and further to the individual patients by predefined keys. To achieve estimates of total costs, patient-specific costs and patient-specified overhead costs were summarised. RESULTS: The mean estimated cost for the ECMO procedure was 73,122 USD (SD 34,786) and median 62,545 USD (range: 34,121-154,817). The mean estimated total hospital costs, including pre- and post-ECMO procedures, was 213,246 USD (SD 12,265), median 191,436 USD (range: 59,871-405,497). On average, 82% of costs for the total hospital stay were related to personnel use, and blood products constituted 7%, lab and radiology 2.5%, disposable items 3% and medication 1.5%. The mean duration of an ECMO procedure was 9.5 days (range: 4-23 days) and the average total length of stay in hospital was 51.5 days (range: 6-123 days). The cost data were converted from Norwegian kroner (NOK) to US dollars (USD), with an exchange rate of 1 USD=5.5 NOK. CONCLUSION: ECMO procedure is a resource-demanding procedure.