Zinc enhances hippocampal long-term potentiation at CA1 synapses through NR2B containing NMDA receptors.

The role of zinc (Zn2+), a modulator of N-methyl-D-aspartate (NMDA) receptors, in regulating long-term synaptic plasticity at hippocampal CA1 synapses is poorly understood. The effects of exogenous application of Zn2+ and of chelation of endogenous Zn2+ were examined on long-term potentiation (LTP) of stimulus-evoked synaptic transmission at Schaffer collateral (SCH) synapses in field CA1 of mouse hippocampal slices using whole-cell patch clamp and field recordings. Low micromolar concentrations of exogenous Zn2+ enhanced the induction of LTP, and this effect required activation of NMDA receptors containing NR2B subunits. Zn2+ elicited a selective increase in NMDA/NR2B fEPSPs, and removal of endogenous Zn2+ with high-affinity Zn2+ chelators robustly reduced the magnitude of stimulus-evoked LTP. Taken together, our data show that Zn2+ at physiological concentrations enhances activation of NMDA receptors containing NR2B subunits, and that this effect enhances the magnitude of LTP.

Complete revascularization is compromised in off-pump coronary artery bypass grafting.

OBJECTIVE: Patients who undergo off-pump coronary artery bypass grafting (OPCAB) commonly receive fewer bypass grafts and are more often incompletely revascularized compared with those receiving conventional coronary artery bypass (CCAB) recipients. Because this can compromise survival, we sought to determine whether patients undergoing OPCAB are incompletely revascularized and whether this affects long-term survival and freedom from cardiac events. METHODS: OPCAB cases (n = 411) performed from January 1, 1997 to June 30, 2003 were considered for inclusion and matching with 874 randomly selected, contemporary CCAB cases. After propensity matching, 308 OPCAB cases and 308 CCAB cases were included in the final analysis. We compared the number of bypass grafts and the completeness of revascularization by coronary territory. Survival and readmission for cardiac causes were monitored for up to 10 years postoperatively, with a median follow-up period of 5.9 years. RESULTS: On average, the patients undergoing OPCAB received significantly fewer distal anastomoses than did those undergoing CCAB (mean ± standard deviation, 2.6 ± 0.9 vs 3.0 ± 1.0, P < .0001). The circumflex territory was the most likely territory to be ungrafted during OPCAB in patients with angiographically significant obstruction (P = .0006). The frequency of complete revascularization was significantly different between the 2 groups (OPCAB, 79.2% vs CCAB, 88.3%; P = .0.002). The OPCAB group had a significantly greater rate of total arterial grafting (OPCAB, 66.6% vs CCAB, 49.7%; P = .0001). No difference was seen in 8-year survival or freedom from cardiac cause hospital readmission between the 2 groups. CONCLUSIONS: Despite receiving fewer distal anastomoses and the decreased frequency of complete revascularization, OPCAB and CCAB techniques produced comparable results.

The risks associated with aprotinin use: a retrospective study of cardiac cases in Nova Scotia.

PURPOSE: In light of the concerns about the safety of aprotinin, we wanted to determine if aprotinin use during cardiac surgery was associated with an increased risk of mortality and morbidity compared with the use of tranexamic acid (TXA). We hypothesized that use of aprotinin is associated with a higher risk of adverse outcomes than use of TXA in our patient population. METHODS: In this retrospective study at a single surgical centre, we examined primary in-hospital outcomes of postoperative mortality, new acute renal failure, and perioperative blood transfusion, and we also investigated secondary outcomes of stroke, infection, and prolonged stay in the intensive care unit (ICU). The effect of the type of antifibrinolytic on outcome was evaluated for aprotinin cases matched 1:1 with TXA cases using propensity score. RESULTS: This study included 3,340 patients who received antifibrinolytics during cardiac surgery (376 patients received aprotinin and 2,964 patients received TXA). Patients who received aprotinin were more often elderly and female; they were more commonly presented with congestive heart failure, atrial fibrillation, renal failure, and lower hemoglobin, and they underwent complex and/or urgent surgery. In the matched sample, in-hospital mortality was significantly higher in the aprotinin group (10.9%) compared with the TXA group (5.9%), and ICU stay >72 hr was significantly increased in the aprotinin group (30.0%) compared with the TXA group (21.7%). There was no significant difference in blood product administration between the two groups. CONCLUSIONS: Aprotinin was associated with an increased risk of in-hospital mortality and morbidity following cardiac surgery, and aprotinin was not associated with a decrease in blood product requirements. Continued use of aprotinin in cardiac surgery should follow careful consideration, weighing the demonstrated risks and potential advantages compared with other TXA.

Chronic traumatic encephalopathy in blast-exposed military veterans and a blast neurotrauma mouse model.

Blast exposure is associated with traumatic brain injury (TBI), neuropsychiatric symptoms, and long-term cognitive disability. We examined a case series of postmortem brains from U.S. military veterans exposed to blast and/or concussive injury. We found evidence of chronic traumatic encephalopathy (CTE), a tau protein-linked neurodegenerative disease, that was similar to the CTE neuropathology observed in young amateur American football players and a professional wrestler with histories of concussive injuries. We developed a blast neurotrauma mouse model that recapitulated CTE-linked neuropathology in wild-type C57BL/6 mice 2 weeks after exposure to a single blast. Blast-exposed mice demonstrated phosphorylated tauopathy, myelinated axonopathy, microvasculopathy, chronic neuroinflammation, and neurodegeneration in the absence of macroscopic tissue damage or hemorrhage. Blast exposure induced persistent hippocampal-dependent learning and memory deficits that persisted for at least 1 month and correlated with impaired axonal conduction and defective activity-dependent long-term potentiation of synaptic transmission. Intracerebral pressure recordings demonstrated that shock waves traversed the mouse brain with minimal change and without thoracic contributions. Kinematic analysis revealed blast-induced head oscillation at accelerations sufficient to cause brain injury. Head immobilization during blast exposure prevented blast-induced learning and memory deficits. The contribution of blast wind to injurious head acceleration may be a primary injury mechanism leading to blast-related TBI and CTE. These results identify common pathogenic determinants leading to CTE in blast-exposed military veterans and head-injured athletes and additionally provide mechanistic evidence linking blast exposure to persistent impairments in neurophysiological function, learning, and memory.

St Jude Medical Epic porcine bioprosthesis: results of the regulatory evaluation.

BACKGROUND: The St Jude Medical Epic heart valve (St Jude Medical, Inc, St Paul, Minn) is a tricomposite glutaraldehyde-preserved porcine bioprosthesis. The St Jude Medical Biocor porcine bioprosthesis is the precursor valve to the St Jude Medical Epic valve. The Epic valve is identical to the Biocor valve except that it is treated with Linx AC ethanol-based calcium mitigation therapy. METHODS: The St Jude Medical Epic valve was implanted in 761 patients (mean age 73.9 ± 9.2 years) between 2003 and 2006 in the US Food and Drug Administration regulatory study in 22 investigational centers. The position distribution was 557 aortic valve replacements, 175 mitral valve replacements, and 29 double valve replacements. Concomitant coronary artery bypass grafting was performed in 50.8% of patients undergoing aortic valve replacement and 36.6% of those undergoing mitral valve replacement. RESULTS: The early mortality was 3.6% in aortic and 2.3% in mitral valve replacement. The follow-up was 1675.5 patient-years with a mean of 2.2 ± 1.2 years/patient. Late mortality was 5.2%/patient-year in aortic and 6.6%/patient-year in mitral valve replacement. The late major thromboembolism rate was 0.98%/patient-year for aortic and 2.6%/patient-year for mitral valve replacement. There were 19 reoperations, including 2 for structural valve deterioration, 1 for thrombosis, 9 for nonstructural dysfunction, and 7 for prosthetic valve endocarditis. The actuarial freedom from reoperation owing to structural valve deterioration for aortic valve replacement at 4 years for age 60 years or less was 93.3% ± 6.4%; for ages 61 to 70 years, 98.1% ± 1.9%; and for older than 70 years, 100% (P = .0006 > 70 vs ≤ 60 years). There were no events of structural deterioration with mitral valve replacement. The actuarial freedom from major thromboembolism for all patients at 4 years was 93.6% ± 1.0%. The 2 cases of structural valve deterioration occurred in aortic valves that became perforated without calcification causing aortic regurgitation. CONCLUSIONS: The performance of the St Jude Medical Epic porcine bioprosthesis is satisfactory at 4 years for both aortic and mitral valve replacement. This study establishes the early clinical performance including durability of this porcine bioprosthesis.

Great mediastinal vein reconstruction using autologous superficial femoral vein superficial femoral vein graft.

BACKGROUND AND AIM: Great mediastinal veins may be reconstructed using autologous, synthetic, or allograft conduits. Autologous conduits have been found superior to other conduit options. The superficial femoral vein (SFV) offers excellent early patency, minimal lower limb morbidity, and ease of harvest without accessory suture lines. Although rarely used, the SFV provides an acceptable alternative for conduit in large vein reconstructions. METHODS: Two recent cases using SFV for great mediastinal vein reconstruction were reviewed and operative technique of vein harvest detailed. RESULTS: This is the first report of successful reconstruction of a left superior vena cava using SFV conduit. Both superior vena cava (SVC) reconstructions reported were perfectly patent at intermediate term follow-up (20 and 14 months) as determined by computed tomography angiogram or magnetic resonance imaging. CONCLUSIONS: Successful and durable reconstruction of the SVC or a persistent left subclavian vein is possible with minimal morbidity using the SFV.

Long-term results of heart operations performed by surgeons-in-training.

BACKGROUND: We investigated the association between trainees performing supervised operations and late outcomes of patients undergoing cardiac surgery. METHODS AND RESULTS: Data were prospectively collected on patients who underwent coronary artery bypass graft surgery, aortic valve replacement, or a combination of these between 1998 and 2005 at the Maritime Heart Center, Halifax, Canada. In-hospital mortality and a composite outcome of in-hospital mortality, stroke, bleeding, intra-aortic balloon pump insertion, renal failure, and sternal infection was compared between teaching (n=1054) and nonteaching cases (n=5877). Late survival and cardiovascular hospital readmissions were also examined. To adjust for baseline risk disparities, we used logistic regression for dichotomous in-hospital outcomes and Cox proportional hazards regression for survival data. Resident cases were significantly more likely to have high-risk features such as depressed ventricular function, redo operation, and urgent or emergent procedure. Resident as primary operator was not independently associated with in-hospital mortality (OR, 1.09; 95% CI, 0.75 to 1.58; P=0.66) or with the composite outcome (OR, 1.01; 95%, CI 0.82 to 1.26; P=0.90). The Kaplan-Meier event-free survival of the 2 groups was equivalent at 1, 3, and 5 years (log-rank P=0.06). By Cox regression, resident cases were not associated with late death or cardiovascular rehospitalization (hazard ratio, 1.05; 95% CI, 0.94 to 1.17; P=0.42). CONCLUSIONS: Cases performed by senior-level cardiac surgery residents were more likely to have greater acuity and complexity than staff surgeon-performed cases. However, clinical outcomes were similar in the short- and long-term. Allowing residents to perform cardiac surgery is not associated with adverse patient outcomes.

A NMDA receptor glycine site partial agonist, GLYX-13, simultaneously enhances LTP and reduces LTD at Schaffer collateral-CA1 synapses in hippocampus.

N-methyl-D-aspartate glutamate receptors (NMDARs) are a key route for Ca2+ influx into neurons important to both activity-dependent synaptic plasticity and, when uncontrolled, triggering events that cause neuronal degeneration and death. Among regulatory binding sites on the NMDAR complex is a glycine binding site, distinct from the glutamate binding site, which must be co-activated for NMDAR channel opening. We developed a novel glycine site partial agonist, GLYX-13, which is both nootropic and neuroprotective in vivo. Here, we assessed the effects of GLYX-13 on long-term synaptic plasticity and NMDAR transmission at Schaffer collateral-CA1 synapses in hippocampal slices in vitro. GLYX-13 simultaneously enhanced the magnitude of long-term potentiation (LTP) of synaptic transmission, while reducing long-term depression (LTD). GLYX-13 reduced NMDA receptor-mediated synaptic currents in CA1 pyramidal neurons evoked by low frequency Schaffer collateral stimulation, but enhanced NMDAR currents during high frequency bursts of activity, and these actions were occluded by a saturating concentration of the glycine site agonist d-serine. Direct two-photon imaging of Schaffer collateral burst-evoked increases in [Ca2+] in individual dendritic spines revealed that GLYX-13 selectively enhanced burst-induced NMDAR-dependent spine Ca2+ influx. Examining the rate of MK-801 block of synaptic versus extrasynaptic NMDAR-gated channels revealed that GLYX-13 selectively enhanced activation of burst-driven extrasynaptic NMDARs, with an action that was blocked by the NR2B-selective NMDAR antagonist ifenprodil. Our data suggest that GLYX-13 may have unique therapeutic potential as a learning and memory enhancer because of its ability to simultaneously enhance LTP and suppress LTD.

Intraoperative graft flow measurements during coronary artery bypass surgery predict in-hospital outcomes.

Transit-time flowmetry enables immediate intraoperative assessment of blood flow parameters in coronary artery bypass grafts (CABG). The present study assesses the predictive value of measured graft flows on early and medium-term outcomes. All cardiac surgery patients with measured graft flows were included. The last intraoperative flow measurements recorded using the Medtronic Butterfly Flowmetry system were used for analysis. Patients were separated into two groups: patients with normal flow in all grafts or patients with abnormal flow > or =1 graft. Any pulsatility index (pulsatility index=min-max flow/mean flow) < or =5 was determined to be normal flow. The study population included 985 patients. Nineteen percent of patients had abnormal flow in > or =1 graft. Overall in-hospital mortality was 4.7% and not significant between the two groups. After adjusting for covariates, the in-hospital composite outcome for adverse cardiac events was more prevalent in the abnormal flow group (31% vs. 17%; P<0.0001) with an odds ratio of 1.7 (CI 1.1-2.7). Survivors to discharge had a mean follow-up of 1.8 years. However, abnormal flow was not an independent predictor of the medium-term mortality and readmission to hospital for cardiac reason following discharge. Our findings suggest that abnormal flows measured intraoperatively are independently associated with short-term in-hospital adverse outcome.

The effect of total arterial grafting on medium-term outcomes following coronary artery bypass grafting.

BACKGROUND: While it is believed that total arterial grafting (TAG) for coronary artery bypass grafting (CABG) confers improved long-term outcomes when compared to conventional grafting with left internal mammary artery and saphenous vein grafts (LIMA+SVG), to date, this has not become the standard of care. In this study, we assessed the impact of TAG on medium-term outcomes after CABG. METHODS: Peri-operative data was prospectively collected on consecutive first-time, isolated CABG patients between 1995 and 2005. Patients were divided into two groups based on grafting strategy: TAG (all arterial grafts no saphenous veins) or LIMA+SVG. Patients who had an emergent status or underwent fewer than two distal bypasses were excluded. Medium term univariate and risk-adjusted comparisons between TAG and LIMA+SVG cases were performed. RESULTS: A total of 4696 CABG patients were included with 1019 patients undergoing TAG (22%). Unadjusted in-hospital mortality was 1.5% for TAG patients compared to 2.0% for LIMA+SVG (p = 0.31). The mean follow-up was 4.8 +/- 2.0 years for TAG patients compared to 6.1 +/- 3.0 years for LIMA+SVG patients (p < 0.0001). At follow-up total mortality (8% vs 19%; p < 0.0001), and the incidence of readmission to hospital for cardiac reasons (29% vs 38%; p < 0.0001) were significantly lower in TAG compared to LIMA+SVG patients. However, after adjusting for clinical covariates, TAG did not emerge as a significant independent predictor of long-term mortality (HR 0.92; CI 0.71-1.18), readmission to hospital (HR 1.02; CI 0.89-1.18) or the composite outcome of mortality and readmission (HR 1.00; CI 0.88-1.15). Risk adjusted survival was better than 88% in both TAG and LIMA-SVG patients at 5 years follow-up. CONCLUSION: Patients undergoing TAG appear to experience lower rates of medium-term all-cause mortality and readmission to hospital for any cardiac cause when compared to patients undergoing LIMA+SVG. However, after adjusting for clinical variables, this difference no longer persists suggesting that at median follow-up there are no mortality or morbidity benefit based on the choice of conduit.

The association between prior percutaneous coronary intervention and short-term outcomes after coronary artery bypass grafting.

BACKGROUND: Increasingly, patients are being referred for coronary artery bypass grafting (CABG) for management of symptoms after prior percutaneous coronary intervention (PCI). In this study, we assessed the impact of prior PCI on inhospital mortality after CABG. METHODS: Perioperative data were collected on patients who underwent first-time CABG at 2 surgical centers. Patients who underwent PCI and CABG during the same admission were excluded. Patients with prior PCI were compared with patients with no prior PCI, and the risk-adjusted impact of prior PCI on inhospital mortality after CABG was determined using both multivariate techniques and propensity score matching techniques. RESULTS: Six thousand thirty-two patients met inclusion criteria. Patients with prior PCI were less likely to be between the ages of 70 and 80 (P < .0001), to have an ejection fraction <0.40 (P < .0001), and to have 3-vessel/left main disease (P < .0001). They were, however, more likely to have Canadian Cardiovascular Society class IV symptoms (P < .0001) and to have an urgent status (P = .02). Rates of inhospital mortality after CABG were higher in patients with prior PCI (3.6% vs 2.3%, P = .02). Using multivariate techniques, prior PCI emerged as an independent predictor of postoperative inhospital mortality (odds ratio 1.93, P = .003). When patients with prior PCI were matched to patients with no prior PCI using propensity scores, inhospital mortality remained higher among patients with prior PCI (3.6% vs 1.7%, P = .01). CONCLUSION: Patients with prior PCI presented for CABG with less comorbidity and diminished coronary disease; yet, they had more advanced symptoms and greater urgency. After adjusting for these differences, prior PCI emerged as an independent predictor of inhospital mortality after CABG.

Assessing the risk of waiting for coronary artery bypass graft surgery among patients with stenosis of the left main coronary artery.

BACKGROUND: Significant controversy remains over how urgently coronary artery bypass graft surgery (CABG) should be scheduled, particularly for patients with stenosis of the left main coronary artery. Our main objective was to evaluate the safety of waiting for CABG among patients with left main coronary artery disease using a standardized triage system. METHODS: We identified 561 consecutive patients with stenosis of the left main coronary artery who were scheduled to undergo CABG between Apr. 1, 1999, and Mar. 31, 2003. Using standardized triage criteria, patients were assigned to 1 of 4 waiting queues: "emergent," "in-hospital urgent," "out-of-hospital semi-urgent A" and "out-of-hospital semi-urgent B." Postoperative outcome measures were in-hospital death from any cause and a composite outcome measure of in-hospital death from any cause, a prolonged requirement for postoperative mechanical ventilation (> 24 h) and a prolonged postoperative hospital stay (> 9 d). Waiting-time variables included the specific queue, whether patients waited longer than the standard time established for each queue and whether patients were upgraded to a more urgent queue. Logistic regression analysis was used to identify independent predictors of the composite outcome; propensity scores (probability of being assigned to a specific queue) were entered into the model to adjust for patient variability among queues. RESULTS: Of the 561 patients, 65 (11.6%) were assigned to the emergent group, 343 (61.1%) to the in-hospital urgent group, 91 (16.2%) to the semi-urgent A queue and 62 (11.1%) to the semi-urgent B queue. Four patients (0.7%) died while waiting for surgery. The median waiting times were as follows: emergent group, 0 days; in-hospital urgent group, 2 days; 30 days in the semi-urgent A group and 49 days in the semi-urgent B group. A total of 52 patients (9.3%) were upgraded to a more urgent queue, and 147 patients (26.2%) waited longer than the standard times for their respective queue. The overall in-hospital mortality was 5.5% (n = 31), and the composite outcome was 32.6% (n = 183). Independent predictors of the composite outcome were myocardial infarction within 7 days before surgery, preoperative renal failure, ejection fraction of less than 40%, age greater than 70 years and stenosis of left main coronary artery greater than 70%. Waiting-time variables were associated with neither a significantly higher mortality nor morbidity outcome. INTERPRETATION: For selected patients with stenosis of the left main coronary artery, waiting for CABG did not appear to be associated with increased mortality or morbidity.

Pulmonary artery to distal bypass for surgery on the descending thoracic aorta.

A variety of extracorporeal techniques have been described in surgery of the descending thoracic and thoracoabdominal aorta. We describe an operative approach involving the cannulation of the pulmonary artery for venous drainage in 12 patients undergoing descending thoracic aortic surgery. In-hospital mortality was 17%; there were no in-hospital deaths for elective cases. There were no cases of post-operative paraplegia. Cannulation of the pulmonary artery is a safe and technically simple means of providing venous drainage during cardiopulmonary bypass in aortic surgery. This is an effective approach to distal perfusion in aortic surgery that is associated with excellent flows and avoids cannulating the left side of the heart.

Identifying patients at risk of intraoperative and postoperative transfusion in isolated CABG: toward selective conservation strategies.

BACKGROUND: Allogeneic blood product use during cardiac operation is often reported to exceed 40% despite published guidelines and costly blood conservation strategies. We developed a predictive model, based on eight preoperative risk factors, of allogeneic blood product transfusion rates in patients undergoing a cardiac procedure. METHODS: All 3,046 consecutive, isolated coronary artery bypass graft (CABG) procedures at a university hospital from 1995 to 1998 were included. A logistic regression model was created to identify independent predictors of allogeneic blood product transfusion. This model was validated using a prospective patient sample. RESULTS: Overall use of allogeneic blood products was 23% with a crude operative mortality of 2.1%. In isolated, elective, first-time CABG cases, 16.9% received allogeneic blood products. Independent predictors of blood product usage in CABG patients were preoperative hemoglobin 12.0 or less, emergent operation, renal failure, female sex, age 70 years or older, left ventricular ejection fraction 0.40 or less, redo procedure, and low body surface area. Prospective validation of this model on 2,117 consecutive isolated CABG patients demonstrated an observed-to-expected allogeneic blood product transfusion rate ratio of 1.06. CONCLUSIONS: This internally validated logistic regression risk model is a sensitive and specific predictor of allogeneic blood product use in patients undergoing isolated CABG. Utilization of this model allows for preoperative risk stratification and may allow for more rational resource allocation of costly blood conservation strategies and blood bank resources.

Training residents in mitral valve surgery.

BACKGROUND: The safety of training residents in complex procedures has not been elucidated. In particular, the impact of resident-performed mitral valve surgery on patient outcomes is unknown. METHODS: All mitral valve procedures performed by residents between 1998 and 2003 were compared with those performed by staff surgeons. Operative mortality and a composite morbidity (reoperation for bleeding, myocardial infarction, infection, stroke, or ventilation > 24 hours) were compared using multivariate analysis. Individual outcomes were compared with the use of propensity scores. RESULTS: There were 1020 cardiac surgeries performed by residents, including 165 mitral valve procedures (86 replacements, 79 repairs). In the same period, the staff surgeons performed 261 mitral procedures. Crude operative mortality for isolated mitral procedures was 5.4% and 4.7% (resident and staff, respectively, p = 1.00). Mitral valve repair including combined procedures had an operative mortality of 3.8% and 4.3% (resident and staff, respectively, p = 1.00). The composite morbidity outcome was 29.7% and 35.3% for resident and staff-performed cases, respectively (p = 0.24). In multivariate analysis, resident was not associated with the adverse outcomes examined (OR 0.80, 95% CI, 0.47, 1.37). The incidence of major adverse outcomes for propensity score-matched mitral valve cases, including combined procedures, were similar between residents and staff, respectively: mortality, 7.4% versus 8.7% (p = 0.67), stroke, 4.0% versus 6.7% (p = 0.30), and reoperation for bleeding, 4.7% versus 9.4% (p = 0.11). CONCLUSIONS: There were no significant differences in morbidity and mortality in patients undergoing mitral valve surgery between resident and staff surgeons. It is possible to train residents to perform complex cardiac cases without adversely affecting outcomes.

Coronary bypass surgery performed off pump does not result in lower in-hospital morbidity than coronary artery bypass grafting performed on pump.

BACKGROUND: There is increasing evidence that cardiopulmonary bypass (CPB) may be responsible for the morbidity associated with coronary artery bypass grafting (CABG) surgery. Recent developments in cardiac stabilization devices have made CABG without CPB feasible. However, there is conflicting evidence to date from published trials comparing outcomes between CABG performed with and without CPB, with some trials indicating an advantage to the avoidance of CPB and others showing little benefit. METHODS AND RESULTS: In a single-center randomized trial, 300 patients requiring CABG surgery at a single institution were prospectively randomized to have the procedure performed with CPB (n=150) or on the beating heart (n=150). Exclusion criteria for the trial included emergency procedure, concomitant major cardiac procedures, ejection fraction <30%, and reoperation. In-hospital outcomes were analyzed on an intention-to-treat basis. A mean of 3.0+/-0.9 grafts were performed in the CPB group compared with 2.8+/-0.9 grafts in the beating-heart group (P=0.06). There were no significant differences between the CPB group and the beating-heart group in mortality (0.7% versus 1.3%; P=1.0), transfusion (8.7% versus 9.3%), perioperative myocardial infarction (0.7% versus 2.7%; P=0.37), permanent stroke (0% versus 1.3%; P=0.50), new atrial fibrillation (32% versus 25%; P=0.20), and deep sternal wound infection (0.7% versus 0%; P=1.0). The mean time to extubation was 4 hours, the mean stay in the intensive care unit was 22 hours, and the median length of hospitalization was 5 days in both groups (P=NS). CONCLUSIONS: In contrast to published trials, we were unable to demonstrate any advantage with CABG performed without CPB in terms of patient morbidity. Excellent results can be obtained with either surgical approach.

The dome of the left atrium: an alternative approach for mitral valve repair.

OBJECTIVE: Surgical repair of mitral insufficiency is most commonly performed through a left atriotomy via the inter-atrial groove or trans-atrial (septal) approach. While the dome of the left atrium approach has been described for mitral replacement concerns have been raised about its adequacy for complex repairs. We report our experience with mitral valve repair carried out through the dome of the left atrium, in comparison with more standard approaches. METHODS: One hundred and thirty-one consecutive patients undergoing mitral valve repair for regurgitation were reviewed retrospectively between 1995 and 2001. Three groups were created based on their surgical approach: inter-atrial groove group (n=43), trans-atrial group (n=18), and dome of the left atrium group (between the superior vena cava and the ascending aorta; n=70). RESULTS: The three groups were similar in terms of pre-operative variables except for significantly older patients in the inter-atrial groove group (P<0.001). The etiology of MR was 24% ischemic (P=ns between groups) and 52% of patients had a concomitant procedure, most commonly coronary artery bypass grafting (P=ns). Valve repairs were achieved using Carpentier techniques including: ring annuloplasty (n=130), isolated posterior leaflet resection (n=69), isolated anterior leaflet (n=11), or bi-leaflet repair (n=19). The overall mortality was 4% with a median length of hospitalization of 7 days and these did not differ significantly between groups. However, longer CPB times (P<0.01) and requirement for prolonged mechanical ventilation (P=0.002) were more frequent in the inter-atrial groove group. CONCLUSION: We report a simple, alternative approach for mitral valve repair via the dome of the left atrium that provides similar outcome to other commonly used approaches.

Is it safe to train residents to perform cardiac surgery?

BACKGROUND: The impact of surgical training on patient outcomes in cardiac surgery is unknown. METHODS: All cases performed by residents from 1998 to 2001 were compared to staff surgeon cases using prospectively collected data. Operative mortality and a composite morbidity of: reoperation for bleeding perioperative myocardial infarction, infection, stroke, or ventilation more than 24 hours were compared using multivariate analysis. RESULTS: Four residents performed 584 cases. The cases were as follows: coronary artery bypass grafting (CABG), 366 cases; aortic valve replacement (AVR) with or without CABG (AVR +/- CABG), 86 cases; mitral valve replacement, 31 cases; mitral valve repair, 25 cases; thoracic aneurysm/dissection, 22 cases; aortic root, 20 cases; transplantations, 14 cases; and adult congenital defect repairs, 20 cases. There were 2,638 CABGs and 363 AVR +/- CABG performed by the staff during the same period. Crude operative mortality in CABG patients was 2.5% (resident) and 2.9% (staff) (p = 0.62). In multivariate analysis, resident was not associated with operative mortality odds ratio (OR) of 0.59 (p = 0.19). Resident cases had a higher incidence of the composite morbidity outcome for CABG cases (19.4% vs 13.6% for staff; p = 0.003). However, in multivariate analysis, resident was not associated with increased morbidity (OR = 1.23, p = 0.16). The AVR +/- CABG crude mortality was 3.6% (resident) and 2.8% (staff) (p = 0.69). Because of the small number of cases (n = 447), operative mortality was combined with the composite morbidity outcome for the AVR +/- CABG model. In all, 16.7% of resident cases and 19.8% of staff cases had the composite outcome or died (p = 0.51). In multivariate analysis resident was not associated with this outcome (OR = 0.74, p = 0.35). CONCLUSIONS: In this analysis of our experience with residency training, the operative morbidity and mortality in CABG and AVR patients was similar for residents and staff. Training residents to perform cardiac surgery appears to be safe.