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.

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.

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.

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.

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.

Surgical repair of postinfarction ventricular septal rupture: risk factors of early and late death.

OBJECTIVE: The aim of the study was to identify risk factors of early and late death after surgical repair of postinfarction ventricular septal rupture. METHODS: During a 25-year period, from May 1981 to August 2006, 102 patients underwent repair of postinfarction ventricular septal rupture. Data were collected on clinical, angiographic, and echocardiographic findings; operative procedures; early morbidity; and survival time. Univariable and multivariable analyses were performed to identify risk factors of 30-day mortality and total mortality. RESULTS: Thirty-day mortality was 33% altogether and decreased from 45% in the first half to 21% in the second half of the period (P = .01). Follow-up was a mean of 5.2 +/- 6.2 years and a median of 2.9 years (range, 0-26.3 years). Five- and 10-year cumulative survival was 50% and 32%, respectively. Shock at surgical intervention and incomplete coronary revascularization were strong and independent risk factors of both 30-day mortality and poor long-term survival. CONCLUSIONS: Early outcome after repair of ventricular septal rupture improved significantly during time, with 30-day mortality being 21% in the last decade. Five- and 10-year cumulative survival was 50% and 32%, respectively. Shock at surgical intervention and incomplete coronary revascularization were strong and independent predictors of poor early and late survival.

Biomarker profile in off-pump and on-pump coronary artery bypass grafting surgery in low-risk patients.

BACKGROUND: The purpose of this study was to investigate the cytokine and chemokine profile in low-risk patients undergoing off-pump and on-pump coronary artery bypass grafting (CABG) surgery by use of a broad panel of cytokines and chemokines. METHODS: Eight consecutive blood samples were obtained from patients enrolled into a prospective, randomized study comparing off-pump and on-pump CABG in a low-risk population. Eleven patients from each group were randomly selected for analysis of 25 different cytokines and chemokines using multiplex technology. Data were compared using two-way repeated measures analysis of variance. RESULTS: Of the 25 biomarkers analyzed, 11 were not detected while 14 increased significantly in both groups. Only three mediators, eotaxin, macrophage inflammatory protein (MIP)-1beta, and interleukin (IL)-12 were significantly different between the two groups, increasing more in the on-pump than in the off-pump group (p < 0.001, p < 0.01, and p < 0.05, respectively). There was a marked, comparable increase in the concentrations of the cytokines IL-6, IL-10, IL-15, and IL-1Ra as well as the chemokines inducible protein (IP)-10, monokine induced by interferon gamma (MIG), monocyte chemoattractant protein 1 (MCP-1), and regulated on activation, normal T cell expressed and secreted (RANTES) in both groups (p < 0.001 for all). There was only a modest, but still statistically significant, increase in IL-8, tumor necrosis factors alpha, and IL-2R, without any intergroup differences. When corrected for hemodilution the production of the antiinflammatory biomarkers IL-1Ra and IL-10 were significantly higher in the on-pump group (p < 0.001 for both). CONCLUSIONS: The cytokine and chemokine production profile of the inflammatory response associated with CABG is largely similar using the off-pump and on-pump techniques in low-risk patients, but slightly higher concentrations of eotaxin, MIP-1beta, and IL-12 were found in the on-pump group.

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.

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.

Training of cardiac surgeons for Bosnia and Herzegovina: outcomes in coronary bypass grafting surgery.

BACKGROUND: Bosnia and Herzegovina did not have invasive cardiac diagnosis or cardiac surgery before the recent war. With assistance from the United States and Norway, a cardiovascular clinic was developed. This study reports center-specific and surgeon-specific clinical outcomes. Since off-pump coronary bypass grafting surgery was prioritized in the treatment of coronary disease, a comparison was made between operations performed with and without cardiopulmonary bypass. METHODS: Surgeons and key staff members were trained in the United States. A Norwegian data management system for cardiac surgery was implemented and cases entered after quality review of the data. A total of 1276 patients were entered; operations were performed with cardiopulmonary bypass in 540 and without in 736. The primary surgeon was entered as a variable in an anonymous fashion. RESULTS: Overall mortality for coronary bypass grafting surgery was 1.6%, and the major complication rate was 4.5%. Patients operated on off-pump received fewer grafts and had a shorter length of stay. Unfavorable outcome was more common in patients when cardiopulmonary bypass was used in the operation. Regression analysis demonstrated that the European System for Cardiac Operative Risk Evaluation (EuroSCORE) and use of cardiopulmonary bypass were predictors of poor outcome. The individual surgeon factor did not impact on outcomes. CONCLUSIONS: Our study confirms that coronary artery bypass grafting surgery may be performed safely in a poor country in a hospital without experience with cardiac surgery. Selection of talented staff and cooperation with international cardiac centers are crucial. Off-pump coronary artery bypass grafting surgery is suitable for a new center and does not require more training than standard procedures.

Clinical and echocardiographic assessment of the Medtronic Advantage aortic valve prosthesis: the Scandinavian multicentre, prospective study.

OBJECTIVE: The aim of this report is the prospective, multicentre evaluation of clinical results and haemodynamic performance of the Medtronic Advantage aortic valve prosthesis. METHODS: From April 2001 to June 2003, 166 patients (male:female 125:41; mean (SD) age 61.8 (11.8) years) received an aortic advantage valve prosthesis. Complete cumulative follow-up was 242.7 patient-years (maximum 3.2; mean 1.6 years). Postoperatively, patients underwent early (within 30 days) and 1 year transthoracic echocardiography. RESULTS: 30 day mortality was 2.4% (n = 4). Kaplan-Meier estimates of freedom from complications and linearised rates were as follows: 96.9 (1.6)% survival; 94.7 (1.3)% (2.06 patients/year) thrombo-embolism; 99.4 (0.6)% (0.4 patients/year) bleeding; 98.8 (0.9)% (0.8 patients/year) non-structural valve dysfunction; 98.8 (0.9)% (0.8 patients/year) reoperation. Valvular mean pressure gradients ranged from 16 (3) mm Hg for size 19 to 7 (2) mm Hg for size 27 and the corresponding effective orifice areas ranged from 1.2 (0.25) to 3.2 (0.66) cm(2). In all, left ventricular mass significantly decreased (p<0.001) and fractional shortening increased (p<0.001) from postoperative to 1 year echocardiography. CONCLUSIONS: Haemodynamic performance and early clinical results of Medtronic advantage in the aortic position were satisfactory and comparable with those of other bileaflet valves in current clinical use.

Off-pump cardiac surgery abolishes complement activation.

BACKGROUND: This prospective randomized study compared the inflammatory response in patients undergoing elective on-pump and off-pump coronary artery bypass grafting. PATIENTS AND METHODS: Forty-four patients undergoing elective coronary artery bypass grafting were recruited with 22 patients randomized to on-pump heart surgery and 22 patients to off-pump coronary bypass surgery. Plasma levels of C3bc, the terminal SC5b-9 complement complex, myeloperoxidase, beta-thromboglobulin and prothrombin fragment F1 + 2 were measured before the operation, intraoperatively, at termination of the operation, and two hours post-operatively. RESULTS: Complement was markedly activated in the on-pump group as indicated by a significant increase in C3bc and SC5b-9 (p < 0.001 for both), whereas no complement activation was seen in the off-pump group (p = 0.001 between the groups). In contrast, both groups showed significant activation of neutrophils, platelets and coagulation, as indicated by an early increase in myeloperoxidase and a post-operative increase in beta-thromboglobulin and F1 + 2, respectively. Notably, there were no intergroup differences with regard to neutrophil and platelet activation, whereas coagulation activation was more pronounced in the off-pump group (p < 0.01). CONCLUSIONS: Off-pump surgery completely eliminated the heart-lung machine-induced complement activation. Neutrophils and platelets were equally activated in both groups, whereas coagulation was enhanced post-operatively in the off-pump group.

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 life-threatening complication of the Nuss procedure for pectus excavatum.

We describe a delayed, life-threatening complication in a boy operated on using the Nuss-procedure 2 months earlier. On admittance he was in shock with cardiac tamponade. An immediate needle aspiration of blood from the pericardium was done before a median sternotomy. The Nuss-bar was removed, and we identified a 1.5-cm laceration in the adventitial layer of the ascending aorta as the source of bleeding. The tear was closed, and the patient had an uneventful recovery. Careful positioning of the bar is necessary to avoid complications. Measures must be taken postoperatively to confirm that the steel bar does not rotate.

Cerebral microembolization during off-pump coronary artery bypass surgery with the Symmetry aortic connector device.

OBJECTIVE: The use of aortic connector systems for proximal vein grafts in off-pump coronary artery bypass grafting might minimize aortic manipulation by eliminating the need for partial aortic clamping. The objective of this study was to asses whether use of a Symmetry connector (St Jude Medical, Inc, St Paul, Minn) reduced intraoperative cerebral embolization. METHODS: Thirty-two consecutive patients underwent off-pump coronary artery bypass grafting. Sixteen patients received at least one mechanical proximal vein graft anastomosis with a Symmetry aortic connector system. Sixteen patients representing the control group underwent operations with standard suturing techniques using partial aortic clamping. During surgical intervention, all patients were monitored continuously with multifrequency transcranial Doppler scanning, which detected and differentiated cerebral emboli. RESULTS: There were significantly more cerebral emboli in the Symmetry group (median, 36) compared with the control group (median, 11; P = .027). This was due to a higher number of gaseous emboli in the Symmetry group than in the control group (median, 27 vs 8; P = .014), whereas there was no significant difference regarding the number of solid emboli (median, 7 vs 3; P = .139). CONCLUSION: Use of a Symmetry connector system during proximal vein graft anastomosis increased the number of emboli to the brain compared with a standard technique in coronary bypass surgery without cardiopulmonary bypass.