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Notes: Aim: External, non-restrictive, macro-porous stents prevent neointima formation in porcine vein grafts and have been proposed as a therapeutic approach to the prevention of late vein graft failure. Since these stents are non-biodegradable and therefore may elicit deleterious long-term, inflammatory, infective and mechanical complications the effect of external macro-porous biodegradable (polyglactin) stents on neointimal and medial thickening in porcine vein grafts was investigated. Methods: Bilateral vein saphenous vein-carotid artery interposition grafting was performed in Large White pigs (22–36 kg, n = 6) with external placement of 8 mm diameter polyglactin stents on one side, the contralateral side acting as a control. One month after surgery, graft wall dimensions were measured on histological sections using computer-aided planimetry and immunocytochemistry undertaken for selected parameters. Results: Polyglactin stents significantly reduced medial thickening compared to the All grafts were patent at explantation. Intimal thickness was significantly lower (p 〈 0.05) in the stented grafts (0.11 ± 0.01 mm) compared to the unstented controls (0.18 ± 0.01 mm). Similarly, medial thickness was significantly lower (p 〈 0.05) in the stented grafts (0.24 ± 0.03 mm) compared to the unstented controls (0.43 ± 0.04 mm) mm. Grafts externally supported with polyglactin had a pronounced increase in inflammatory cells (in particular, giant cells) around the biodegradable stent compared to both unstented controls and previously studied Dacron stented grafts. The space between graft and stent had become organised into a neo-adventitia with abundant microvessels which stained positively for VEGF and lectin (markers of micorvessels and endothelial cells). Conclusions: An over-size biodegradable stent reduces medial thickening, a component of late vein graft failure in experimental grafts. If subsequent studies confirm the preservation of this beneficial effect when the stent biodegrades completely, this form of stent may have an advantage over permanent stent material in the clinical use of external stenting to prevent vein graft thickening and failure.

Notes: Objectives: A prospective study to evaluate pathology-related differences in cardiac troponin I (TnI) release and its relation to clinical outcome after paediatric open-heart surgery. Backgound: The degree of perioperative myocardial injury is determined by the ischaemic duration but also by the pathology and preoperative state of the heart (acidosis or cyanosis). Cardiac TnI is a marker of myocardial injury but little is known about the differences in TnI release between different pathologies. Methods: Troponin I was measured in 133 consecutive children undergoing repair of atrial (ASD, n = 41) and ventricular septal defects (VSD, n = 46) and Tetralogy of Fallot (TOF, n = 46). The length of the right ventricular outflow tract (RVOT) incision in the latter was classified as either minimum(n = 33) or extended(n = 13) according to the normal diameter of the pulmonary valve to body weight. Results: There was no mortality. Postoperative TnI levels were lesion-specific and did not correlate with clinical outcome for ASDs (〈link href="#t2"〉Table 1). For VSDs, peak TnI correlated with the durations of inotropic support (r = 0.69, p = 0.0001), ventilation (r = 0.64, p 〈 0.0001) and intensive care unit (ICU) stay (r = 0.60, p 〈 0.0001) with infants (〈1 year old, n = 29) showing higher peak TnI (4.11 ± 0.46 vs 2.49 ± 0.33ng/ml, p = 0.02) and worse clinical outcome than children. For TOF, peak TnI correlated with the duration of inotropic support (r = 0.51, p = 0.0004), ventilation (r = 0.36, p = 0.02) and ICU stay (r = 0.55, p = 0.0001) whereas arterial oxygen saturation showed a negative correlation with these (r =−0.39 to −0.49, p 〈 0.05). Those undergoing an extended RVOT incision had greater peak TnI and worse clincial outcome than those with a minimum RVOT incision (〈link href="#t3"〉Table 2). Conclusions: TnI is a reliable marker of early post-operative recovery after repair of VSDs and TOF. Age (〈1 year) for patients with VSDs and right ventriculotomy length in TOF are important determinants of clinical outcome.〈tabular xml:id="t2"〉1〈title type="main"〉 Patient Characteristics 〈table frame="topbot"〉〈tgroup cols="4" align="left"〉〈colspec colnum="1" colname="col1" align="left"/〉〈colspec colnum="2" colname="col2" align="center"/〉〈colspec colnum="3" colname="col3" align="center"/〉〈colspec colnum="4" colname="col4" align="center"/〉〈thead valign="bottom"〉〈entry morerows="1" valign="top" align="center"〉 ASD (n = 41) 〈entry morerows="1" valign="top" align="center"〉 VSD (n = 46) 〈entry morerows="1" valign="top" align="center"〉 TOF (n = 46) 〈tbody valign="top"〉Age (months) 71.4 ± 6.9 25.3 ± 6.2 18.0 ± 2.9 ACC time (min) 26.4 ± 2.7* 39.2 ± 2.9 49.1 ± 3.6 Inotrope duration (hours) 9.5 ± 1.4* 37.2 ± 6.5 71.6 ± 9.0† Ventilation time (hours) 6.9 ± 1.1

Notes: Aim: The vasculopathic impact of homocysteine (HCy) is mediated through the generation of superoxide, a phenomenon augmented by copper (Cu2+). Cardiopulmonary bypass (CPB) also elicits oxidant stress. Since oxygen free radicals may play a role in both early and late vein graft failure, the blood levels of HCy and Cu2+ and related parameters, before and after surgery, were investigated in patients undergoing coronary artery bypass graft surgery (CABG), both with (on pump) and without CPB (off pump). Methods: Blood samples were taken from 20 consecutive patients (10 on-pump and 10 off-pump) undergoing CABG, one day pre-operatively (D0) and one day (D1) and six days (D6) post-operatively. Plasma HCy, serum Cu2+, caeruloplasmin (CP) and vitamin B12 and red cell folate were then measured. Results: Pre-operative (D0) plasma concentrations of HCy were below the accepted risk factor value of 14 μmol/l. At D1 there was a reduction in all parameters in both groups, which is ascribable to hemodilution. However, in both on pump and off pump groups, HCy, Cu2+ and CP were all significantly increased at D6. Concentrations of red cell folate were not significantly altered and serum vitamin B12 was significantly increased at D6, indicating that the increase in HCy was not due to a reduction in these vitamins. When comparing on-pump to off pump, there were no significant differences between any parameter except for Cu2+ which was significantly greater in the on pump group compared to the off pump group at D6.〈tabular xml:id="t5"〉1〈title type="main"〉 Circulating Parameters Following CABG (Means ± SEM; n = 10 ) *p 〈 0.05 vs Pre-Operative Levels and #p 〈 0.05 on Pump vs Off Pump 〈table frame="topbot"〉〈tgroup cols="6" align="left"〉〈colspec colnum="1" colname="col1" align="left"/〉〈colspec colnum="2" colname="col2" align="left"/〉〈colspec colnum="3" colname="col3" align="left"/〉〈colspec colnum="4" colname="col4" align="left"/〉〈colspec colnum="5" colname="col5" align="left"/〉〈colspec colnum="6" colname="col6" align="left"/〉〈thead valign="bottom"〉〈entry morerows="1" valign="top" align="center"〉 HCy (μmol/l) 〈entry morerows="1" valign="top" align="center"〉 Cu2+ (μmol/l) 〈entry morerows="1" valign="bottom" align="center"〉CP (g/l)〈entry morerows="1" valign="top" align="center"〉 Folate (mg/l) 〈entry morerows="1" valign="top" align="center"〉 VitB12 (ng/l) 〈tbody valign="top"〉On pump: D0 10.5 ± 1.3 13.9 ± 3.2 0.30 ± 0.05 388 ± 182 261 ± 75 Off pump: D0 9.8 ± 1.2 13.6 ± 3.3 0.35 ± 0.12 340 ± 78 240 ± 140 On pump: D1 9.2 ± 1.4 10.5 ± 3.2 0.23 ± 0.10 357 ± 168 170 ± 62 Off pump: D1 8.7 ± 1.3 13.2 ± 2.8 0.32 ± 0.10 351 ± 84 190 ± 89 On pump: D6 12.7 ± 1.2* 21.9 ± 2.5*# 0.40 ± 0.04* 394 ± 150 410 ± 160* Off pump: D6 11.1 ± 1.3* 19.0 ± 2.6* 0.40 ± 0.07* 331 ± 57 385 ± 169* Conclusions: Contrary to other reports, the pre-operative plasma concentrations of HCy in this study suggest that HCy is not a risk factor for coronary artery disease. However, following CABG, the significant increase in HCy and Cu2+ may be of pathological importance since Cu2+ augments the release of superoxide from HCy. The greater increase in serum Cu2+ in the on-pump group indicates that CPB may promote oxidant stress through elevation of this potent transition metal.

Notes: Objective: Coronary artery bypass grafting (CABG) in overweight patients carries significant morbidity. We compare the effectiveness of off-pump coronary artery bypass (OPCAB) surgery versus conventional CABG using cardiopulmonary bypass and cardioplegic arrest, in a consecutive series of overweight patients. Methods:From April 1996 to April 2001, data from 4321 patients undergoing coronary revascularisation (mortality 1.4%) were prospectively entered into the Patients Analysis and Tracking System. Data were extracted for all patients with a body mass index (BMI) ≥ 25. In hospital mortality and early morbidity were compared between patients undergoing on- and off-pump coronary surgery. A risk-adjusted analysis was also carried out to assess the influence of surgery on outcomes. Results: 2844 overweight patients with BMI ≥ 25 were identified, and of these 674 (23.7%) were operated on with off-pump surgery. On-pump patients were less likely to have unstable angina, hypercholesterolaemia, to have coronary disease involving the left main stem, or to have a BMI ≥ 30. However, they had more extensive coronary disease, were more likely to have suffered previous myocardial infarction, and received more grafts than those undergoing off-pump surgery. Intra- and post-operative arrhythmias, inotropic use, and post-operative low cardiac output, use of IABP, blood loss, transfusion requirement, chest infections, neurological complications including permanent stroke, ICU and hospital stay all were significantly reduced in the off-pump group (all p 〈 0.05). After adjustment for age, gender, ejection fraction, extent of coronary disease, and degree of urgency, odd ratios (ORs) for most of the adverse outcomes investigated, confirmed significant benefit of off-pump surgery (table). The point estimate of the adjusted effect size for in-hospital mortality also indicated benefit from off-pump surgery (table).〈table frame="topbot"〉〈tgroup cols="6" align="left"〉〈colspec colnum="1" colname="col1" align="left"/〉〈colspec colnum="2" colname="col2" align="left"/〉〈colspec colnum="3" colname="col3" align="left"/〉〈colspec colnum="4" colname="col4" align="char" char="."/〉〈colspec colnum="5" colname="col5" align="center"/〉〈colspec colnum="6" colname="col6" align="left"/〉〈thead valign="bottom"〉〈entry morerows="1" valign="bottom" align="center"〉 Variable 〈entry morerows="1" valign="top" align="center"〉 On-Pump (2169) 〈entry morerows="1" valign="top" align="center"〉 Off-Pump (674) 〈entry morerows="1" valign="top" align="center"〉 OR/Mean Difference 〈entry morerows="1" valign="bottom" align="center"〉 95% CI 〈entry morerows="1" valign="bottom" align="center"〉 p 〈tbody valign="top"〉Death20 (0.92%)2 (0.29%)0.370.08, 1.590.18Postoperative MI35 (1.6%)14 (2.0%)1.370.72, 2.620.337New Inotropes879 (40.5%)219 (32.5%)0.80.66, 0.970.02New IABP54 (2.5%)5 (0.7%)0.320.12, 0.80.015Ward arrhythmia320 (14.8%)65 (9.6%)0.630.47, 0.840.002Chest Infection106 (4.9%)14 (2.1%)0.430.24, 0.760.004Neurolog. Complic.59 (2.7%)6 (0.9%)0.360.15, 0.850.02Blood Loss (ml)939.9(512.3)856.2 (582.1)−60.8−111.7, −9.870.019Total RBCs (unit)1.05 (1.51)0.436 (1.52)−0.51−0.65, −0.370.0001Total Platelets (unit)0.24 (0.81)0.08 (0.455)−0.157−0.23, −0.080.0001Total FFP (unit)0.49 (1.48)0.126 (0.72)−0.38−0.5, −0.250.0001Sternal rewiring17 (0.78%)1 (0.14%)−0.220.03, 1.70.15Renal complications98 (4.5%)24 (3.56%)−0.740.44, 1.250.265Hospital stay (day)7.76 (4.26)6.64 (3.04)−0.94−1.39, −0.490.0001 Conclusions: These results suggest that off-pump surgery is safe, effective and associated with reduced morbidity in overweight patients.

Notes: Objective: Coronary artery bypass grafting (CABG) in overweight patients carries significant morbidity. We compare the effectiveness of off-pump coronary artery bypass (OPCAB) surgery versus conventional CABG using cardiopulmonary bypass and cardioplegic arrest, in a consecutive series of overweight patients. Methods: From April 1996 to April 2001, data from 4321 patients undergoing coronary revascularisation (mortality 1.4%) were prospectively entered into the Patients Analysis and Tracking System. Data were extracted for all patients with a body mass index (BMI) ≥ 25. In hospital mortality and early morbidity were compared between patients undergoing on- and off-pump coronary surgery. A risk-adjusted analysis was also carried out to assess the influence of surgery on outcomes. Results: 2844 overweight patients with BMI ≥ 25 were identified, and of these 674 (23.7%) were operated on with off-pump surgery. On-pump patients were less likely to have unstable angina, hypercholesterolaemia, to have coronary disease involving the left main stem, or to have a BMI ≥ 30. However, they had more extensive coronary disease, were more likely to have suffered previous myocardial infarction, and received more grafts than those undergoing off-pump surgery. Intra- and post-operative arrhythmias, inotropic use, and post-operative low cardiac output, use of IABP, blood loss, transfusion requirement, chest infections, neurological complications including permanent stroke, ICU and hospital stay all were significantly reduced in the off-pump group (all p 〈 0.05). After adjustment for age, gender, ejection fraction, extent of coronary disease, and degree of urgency, odd ratios (ORs) for most of the adverse outcomes investigated, confirmed significant benefit of off-pump surgery (table). The point estimate of the adjusted effect size for in-hospital mortality also indicated benefit from off-pump surgery (table).〈table frame="topbot"〉〈tgroup cols="6" align="left"〉〈colspec colnum="1" colname="col1" align="left"/〉〈colspec colnum="2" colname="col2" align="left"/〉〈colspec colnum="3" colname="col3" align="left"/〉〈colspec colnum="4" colname="col4" align="char" char="."/〉〈colspec colnum="5" colname="col5" align="char" char="."/〉〈colspec colnum="6" colname="col6" align="left"/〉〈thead valign="bottom"〉〈entry morerows="1" valign="bottom" align="center"〉 Variable 〈entry morerows="1" valign="top" align="center"〉 On-Pump (2169) 〈entry morerows="1" valign="top" align="center"〉 Off-Pump (674) 〈entry morerows="1" valign="top" align="center"〉 OR/Mean Difference 〈entry morerows="1" valign="bottom" align="center"〉 95% CI 〈entry morerows="1" valign="bottom" align="center"〉 p 〈tbody valign="top"〉Death20 (0.92%)2 (0.29%)0.370.08, 1.590.18Postoperative MI35 (1.6%)14 (2.0%)1.370.72, 2.620.337New Inotropes879 (40.5%)219 (32.5%)0.80.66, 0.970.02New IABP54 (2.5%)5 (0.7%)0.320.12, 0.80.015Ward arrhythmia320 (14.8%)65 (9.6%)0.630.47, 0.840.002Chest Infection106 (4.9%)14 (2.1%)0.430.24, 0.760.004Neurolog. Complic.59 (2.7%)6 (0.9%)0.360.15, 0.850.02Blood Loss (ml)939.9 (512.3)856.2 (582.1)−60.8−111.7, −9.870.019Total RBCs (unit)1.05 (1.51)0.436 (1.52)−0.51−0.65, −0.370.0001Total Platelets (unit)0.24 (0.81)0.08 (0.455)−0.157−0.23, −0.080.0001Total FFP (unit)0.49 (1.48)0.126 (0.72)−0.38−0.5, −0.250.0001Sternal rewiring17 (0.78%)1 (0.14%)−0.220.03, 1.70.15Renal complications98 (4.5%)24 (3.56%)−0.740.44, 1.250.265Hospital stay (day)7.76 (4.26)6.64 (3.04)−0.94−1.39, −0.490.0001 Conclusions: These results suggest that off-pump surgery is safe, effective and associated with reduced morbidity in overweight patients.