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Biomedical subjects

Peter K Smith

Publications and source records attributed to Peter K Smith.

At least 19 recordsLinked to original sources
PubMed2007

Physician payment for 2007: a description of the process by which major changes in valuation of cardiothoracic surgical procedures occurred.

Throughout the last 3 years, the Society of Thoracic Surgeons (STS) has put forth a major effort towards more accurate valuation of the work performed by cardiothoracic surgeons. The culmination of these efforts was realized on November 1, 2006, when the Centers for Medicare & Medicaid Services published the Final Rule which markedly increased the physician work values for the most frequently performed cardiothoracic surgery procedures. This article recounts the innovative approach taken by the STS during these extended efforts.

Cardiac Surgical Procedures↗
PubMed2006

Impact of internal mammary artery conduit on long-term outcomes after percutaneous intervention of saphenous vein graft.

BACKGROUND: The influence of an internal mammary artery (IMA) graft on long-term outcomes after percutaneous saphenous vein graft (SVG) intervention is currently unknown. METHODS AND RESULTS: To examine the impact of IMA on outcomes in patients undergoing SVG interventions, we analyzed 2119 patients from the Duke Cardiovascular Disease Database (1986-2003) with prior coronary artery bypass surgery undergoing cardiac catheterization who had at least 1 SVG graft. Patients were categorized into 4 groups: group I, SVG intervention and patent IMA; group II, no SVG intervention and patent IMA; group III, SVG intervention without patent IMA; and group IV, no SVG intervention without patent IMA. At a median follow-up of 4.8 years (interquartile range, 2.1 to 8.8 years), adjusted survival rates in groups I, II, III, and IV were 72.8%, 72.3%, 64.5%, and 58.9%, respectively. Multivariate Cox proportional hazards modeling showed similar survival for groups I and II (P=0.63) and for groups III and IV (P=0.33). The presence of IMA graft was related to lower long-term mortality (adjusted hazard ratio [HR], 0.69; 95% CI, 0.58 to 0.82), whereas SVG intervention was not associated with long-term mortality (adjusted HR, 0.94; 95% CI, 0.81 to 1.10). In contrast, the adjusted event-free rates for nonfatal myocardial infarction were lower in the SVG intervention groups (groups I and III) than in the non-SVG intervention groups (groups II and IV) (HR for SVG intervention versus no SVG intervention, 3.19; 95% CI, 2.18 to 4.66), with the presence of patent IMA conferring no significant benefit on this outcome (HR, 1.37; 95% CI, 0.91 to 2.08). CONCLUSIONS: In patients undergoing SVG interventions, survival, but not nonfatal myocardial infarction, is favorably influenced by the presence of patent IMA. In contrast, SVG intervention had no measurable survival benefit but was associated with an increased risk of nonfatal myocardial infarction.

Aged↗
PubMed2006

Prognosis of patients taking selective serotonin reuptake inhibitors before coronary artery bypass grafting.

Depression is increasingly recognized as an independent prognostic risk factor in patients with coronary artery disease and coronary artery bypass grafting (CABG). The use of selective serotonin reuptake inhibitors (SSRIs) for depression in patients with cardiac disease is becoming more prevalent. We examined the long-term outcomes of patients on SSRIs before CABG. We prospectively examined collected data in the Duke Databank for Cardiovascular Disease from January 1, 1999 to December 31, 2003. The median and maximum follow-up periods were 3 and 6 years, respectively. We screened patients who underwent CABG (n = 5,364) and excluded those who underwent simultaneous CABG and valvular surgery (n = 570). SSRI antidepressants included fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, escitalopram, venlafaxine, and clomipramine, and their use was determined from the inpatient pharmacy records during the index hospitalization. Outcomes included event-free survival from all-cause mortality, rehospitalization, and a composite end point of all-cause mortality or rehospitalization. Of 4,794 CABG-only patients, 246 (5.1%) took SSRIs before CABG. The SSRI group had a higher prevalence of diabetes, hypercholesterolemia, hypertension, cerebrovascular disease, peripheral vascular disease, and previous cardiovascular intervention. After adjustment for baseline differences, patients on SSRIs before CABG had increased risks of mortality, rehospitalization, and the composite end point (hazard ratio 1.61, 95% confidence interval 1.17 to 2.21, p = 0.003; hazard ratio 1.52, 95% confidence interval 1.30 to 1.77, p <0.0001; and hazard ratio 1.46, 95% confidence interval 1.26 to 1.70, p <0.0001, respectively). In conclusion, SSRI use before CABG was associated with a higher risk of long-term post-CABG mortality and rehospitalization. The explanation behind these findings requires further research.

Aged↗
PubMed2006

Effect of pexelizumab in coronary artery bypass graft surgery with extended aortic cross-clamp time.

BACKGROUND: Prolonged cross-clamp time during cardiac surgery increases the risk of postoperative mortality and myocardial injury. This subanalysis from the pexelizumab for reduction of infarction and mortality in coronary artery bypass grafting surgery (PRIMO-CABG) trial, a phase III double-blind, placebo-controlled study of 3,099 patients undergoing on-pump coronary artery bypass graft surgery with or without valve surgery, assessed the impact of pexelizumab, an investigational C5 complement inhibitor, on postoperative outcomes after prolonged aortic cross-clamp time. METHODS: The composite endpoint of death or myocardial infarction through postoperative day 30 and death alone through days 30, 90, and 180 were examined in subpopulations of patients across different cross-clamp times. RESULTS: After prolonged cross-clamping (> or = 90 minutes), death, or myocardial infarction through day 30 and death through days 30, 90, and 180 were significantly increased in the intent-to-treat population and were even higher in patients with two or more prespecified risk factors, compared with all patients cross-clamped less than 90 minutes. Pexelizumab significantly reduced the incidence of death or myocardial infarction through day 30, and significantly reduced the incidence of mortality through day 180, in patients with two or more risk factors that required prolonged cross-clamp time. Pexelizumab also significantly reduced perioperative myocardial injury in all patients requiring prolonged cross-clamp time. CONCLUSIONS: In this retrospective, subgroup analysis, pexelizumab reduced postoperative morbidity and myocardial injury in patients with multiple risk factors who underwent prolonged cross-clamp time during coronary artery bypass surgery. The clinical benefit of pexelizumab may be related to the effect of complement inhibition in the presence of potential ischemic-reperfusion injury associated with prolonged aortic cross-clamp time.

Antibodies, Monoclonal↗
PubMed2006

Selection of surgical or percutaneous coronary intervention provides differential longevity benefit.

BACKGROUND: Treatment of coronary artery disease (CAD) is evolving with better medications, improvements in percutaneous coronary intervention (PCI), and enhanced techniques for coronary artery bypass grafting (CABG). METHODS: In this study, 18,481 patients with significant (>75% stenosis) CAD treated at a single center between 1986 and 2000 were assigned to one of three groups based on initial treatment strategy: medical therapy (MED) (n = 6862), PCI (n = 6292), or CABG (n = 5327). Each group was categorized into 3 groups according to baseline severity of CAD: low-severity (predominantly 1-vessel), intermediate-severity (predominantly 2-vessel), and high-severity (all 3-vessel), and prospectively evaluated in Cox models for all-cause mortality adjusted for cardiac risk, comorbidity, and propensity for selection of a specific treatment. Treatments were compared for the entire period and three eras (1: 1986 to 1990; 2: 1991 to 1995; 3: 1996 to 2000), the last encompassing widespread availability of PCI with stenting. RESULTS: Survival significantly improved in all groups for all degrees of CAD, despite increasing severity of illness. Revascularization strategies provided significant survival over MED with 8.1, 10.6, and 23.6 additional months per 15 years of follow-up for low-severity, intermediate-severity, and high-severity CAD, respectively. Therapeutic improvements led to increased survival of 5.3 additional months per 7 years of follow-up (95% confidence interval, 0.2 to 10.2; p = 0.039) in era 3 for CABG compared with PCI for high-severity CAD. CONCLUSIONS: Initial revascularization strategies result in significant survival advantage over MED for all CAD levels. Patients with high-severity CAD have reduced survival with PCI compared with those initially treated with CABG.

Aged↗
PubMed2005

Relation of early saphenous vein graft failure to outcomes following coronary artery bypass surgery.

Up to 20% of saphenous vein grafts (SVGs) fail within 2 years of coronary artery bypass grafting (CABG). The long-term effects of early SVG failure on major clinical events remain undefined in contemporary patient populations. We sought to examine the relation between early SVG failure and long-term outcomes after CABG. Using the Duke Cardiovascular Databank, we examined baseline clinical and angiographic characteristics and clinical outcomes among patients who underwent catheterization 1 to 18 months after their first CABG from 1986 to 2004. Patients were classified on the basis of their worst SVG stenosis as having no (<25%), noncritical (25% to 74%), critical (75% to 99%), or occlusive (100%) SVG disease. Our primary outcome measure was the composite of death, myocardial infarction, or repeat revascularization after catheterization. Of 1,243 patients included in the analysis, 27.9% had no, 11.9% had noncritical, 20.8% had critical, and 39.3% had occlusive SVG disease. At 10 years, the corresponding adjusted composite event rates were 41.2%, 56.2%, 81.2%, and 67.1%, respectively (p <0.0001). Most events occurred immediately after catheterization in patients with critical and occlusive SVG disease and were primarily repeat revascularization. On multivariate analysis, critical, nonocclusive SVG disease was the strongest predictor of the composite outcome (hazard ratio 2.36, 95% confidence interval 2.00 to 2.79, p <0.0001). In conclusion, in contemporary clinical practice, early SVG failure is associated with worse long-term outcomes after CABG.

Aged↗
PubMed2005

Impact of mitral valve regurgitation evaluated by intraoperative transesophageal echocardiography on long-term outcomes after coronary artery bypass grafting.

BACKGROUND: It is unclear if mild or moderate mitral valve regurgitation (MR) should be repaired at the time of coronary artery bypass grafting (CABG). We sought to determine the long-term effect of uncorrected MR, measured by intraoperative transesophageal echocardiography (TEE), in CABG patients. METHODS AND RESULTS: Between May 1999 and September 2003, data were gathered for 3264 consecutive patients who underwent isolated CABG and had MR graded by intraoperative TEE. MR was graded on the following 5 levels: none, trace, mild, moderate, and severe. Patients who had severe MR or who underwent mitral valve surgery were eliminated from the analysis. The remaining patients were combined into the following 3 groups: none or trace, mild, and moderate MR. Preoperative and follow-up data were 99% complete. The median length of follow-up was 3.0 years. Multivariable analysis controlling for important preoperative risk factors was performed to determine predictors of death and death/hospitalization for heart failure. Increasing MR was a risk factor for death [hazard ratio (HR), 1.44; P<0.001] and death/heart failure hospitalization (HR, 1.34; P<0.01). When patients with moderate MR were eliminated from the analysis, mild MR was a risk factor for death (HR, 1.34; P=0.011) and death/hospitalization for heart failure (HR, 1.34; P<0.001). CONCLUSIONS: Even mild MR, identified by intraoperative TEE, predicts worse outcomes after CABG. Revascularization alone did not eliminate the negative long-term effects of mild MR. CABG patients with uncorrected mild or moderate MR are at increased risk for death and heart-failure hospitalization; consideration for surgical repair or more aggressive medical management and follow-up is warranted.

Aged↗
PubMed2005

Risk-adjusted short- and long-term outcomes for on-pump versus off-pump coronary artery bypass surgery.

BACKGROUND: Surgeons have adopted off-pump coronary artery bypass grafting (OPCAB) in an effort to reduce the morbidity of surgical revascularization. However, long-term outcome of OPCAB compared with conventional coronary artery bypass grafting (CABG) remains poorly defined. METHODS AND RESULTS: Using logistic regression analysis and proportional hazards modeling, short-term and long-term outcomes (perioperative mortality and complications, risk-adjusted survival, and survival/freedom from revascularization) were investigated for patients who underwent OPCAB (641 patients) and CABG-cardiopulmonary bypass (5026 patients) from 1998 to 2003 at our institution. For these variables, follow-up was 98% complete. OPCAB patients were less likely to receive transfusion (odds ratio for OPCAB, 0.80; P=0.037), and there were trends toward improvement in other short-term outcomes compared with CABG-cardiopulmonary bypass. Long-term outcomes analysis demonstrated no difference in survival, but OPCAB patients were more likely to require repeat revascularization (OPCAB hazard ratio, 1.29; P=0.020). CONCLUSIONS: OPCAB patients were less likely to receive transfusion during their hospitalization for surgery but had higher risk for revascularization in follow-up. These results highlight the need for a large randomized, controlled trial to compare these 2 techniques.

Aged↗
PubMed2005

Infectious complications after cardiac surgery: lack of association with fresh frozen plasma or platelet transfusions.

OBJECTIVE: The purpose of this study was to examine the effect of perioperative transfusion of platelets and fresh frozen plasma (FFP) on infection rates after cardiac surgery. DESIGN: Retrospective study comparing infection rates after cardiac surgery among patients receiving combinations of packed red blood cells (PRBCs), platelets, and FFP. SETTING: Tertiary care university teaching hospital. PARTICIPANTS: All elective primary coronary artery bypass (CABG) surgery patients from July 1995 to January 1998 before introduction of leukocyte-reduced blood products. INTERVENTIONS: Multivariate logistic and linear regression models were applied to identify clinical risk factors for postoperative infection and to determine the relationship between perioperative administration of PRBCs, platelets, and FFP with postoperative infection. MEASUREMENTS AND MAIN RESULTS: Transfusion of PRBCs, diabetes, age, preoperative hematocrit, and the duration of cardiopulmonary bypass were significantly associated with postoperative infection; platelet or FFP transfusion added no additional risk to PRBC transfusion alone. CONCLUSIONS: Infectious complications in a population of adult primary CABG surgery patients were not increased by transfusion of platelets or FFP. It is PRBC transfusion that confers an increased risk of postoperative infection in this population.

Bacterial Infections↗
PubMed2004

Economic impact of drug-eluting stents on hospital systems: a disease-state model.

BACKGROUND: Drug-eluting intracoronary stents decrease restenosis and later revascularization. The US Department of Health and Human Services (HHS), recognizing the financial and clinical impact of this technology, recently proposed accelerated reimbursement to hospitals. METHODS AND RESULTS: A disease state-transition computer model simulated the clinical and economic consequences to hospitals of drug-eluting stents over 5 years. Model parameters combined information from a longitudinal clinical database, a hospital cost-accounting system, and a survey instrument. Simulations were repeated 1000 times for each set of parameters. With 85% of stent procedures shifted to drug-eluting stents in the first year of availability, the mean number of repeat revascularizations dropped by 60.4% at year 5. With no changes in reimbursement policy, a hospital with a catheterization laboratory volume of 3112 patients yearly converted from a 2.01 million dollars (M) annual profit to an 8.10 M dollars loss in the first year (95% CI 8.09 M dollars to 8.12 M dollars) and 8.7 M dollars annual losses in later years. This represented an overall change in cash flow of 55.71 M dollars (95% CI 55.66 M dollars to 55.76 M dollars) away from the hospital over 5 years. The incremental reimbursement proposed by HHS reduced this loss to 4.75 M dollars in the first year and to 5.6 M dollars annually thereafter. In sensitivity analyses, the conversion of patients from bypass surgery to drug-eluting stents was the largest driver of overall cash flow shifts. CONCLUSIONS: Although Medicare has proposed to increase reimbursement to ease the impact of drug-eluting stents on hospitals, this increase will not totally offset the costs.

Angioplasty, Balloon, Coronary↗
PubMed2004

Cost analysis of aprotinin for coronary artery bypass patients: analysis of the randomized trials.

BACKGROUND: The full kallikrein-inhibiting dose of aprotinin has been shown to reduce blood loss, transfusion requirements, and the systemic inflammatory response associated with cardiopulmonary bypass graft surgery (CABG). A half-dose regimen, although having a reduced delivery cost, inhibits plasmin and fibrinolysis without substantially effecting kallikrein-mediated inflammation associated with bypass surgery. The differing pharmacologic effects of the two regimens impact the decision-making process. The current study assessed the medical cost offset of full-dose and half-dose aprotinin from short- and long-term perspectives to provide a rational decision-making framework for clinicians. METHODS: To estimate CABG admission costs, resource utilization and clinical data from aprotinin clinical trials were combined with unit costs estimated from a Duke University-based cost model. Lifetime medical costs of stroke and acute myocardial infarction were based on previous research. RESULTS: Relative to placebo, the differences in total perioperative cost for primary CABG patients receiving full-dose or half-dose aprotinin were not significant. When lifetime medical costs of complications were considered, total costs in full-dose and half-dose aprotinin-treated patients were not different relative to that of placebo. Total perioperative cost was significantly lower for repeat CABG patients treated with aprotinin, with savings of $2,058 for full-dose and $2,122 for half-dose patients when compared with placebo. Taking lifetime costs of stroke and acute myocardial infarction into consideration, the cost savings estimates were $6,044 for full-dose patients and $4,483 for half-dose patients, due to substantially higher lifetime stroke costs incurred by the placebo patients. CONCLUSIONS: Using this cost model, use of full-dose and half-dose aprotinin in primary CABG patients was cost neutral during hospital admission, whereas both dosing regimens were significantly cost saving in reoperative CABG patients. Additional lifetime cost savings were realized relative to placebo due to reduced complication costs, particularly with the full-dose regimen. As the full kallikrein-inhibiting dose of aprotinin has been shown to be safe and effective, the current results support its use in both primary and repeat CABG surgery. No demonstrable economic advantage was observed with the half-dose aprotinin regimen.

Adult↗
PubMed2004

Metoprolol and coronary artery bypass grafting surgery: does intraoperative metoprolol attenuate acute beta-adrenergic receptor desensitization during cardiac surgery?

UNLABELLED: Cardiac surgery results in significant impairment of beta-adrenergic receptor (beta AR) function and is a cause of depressed myocardial function after surgery. We previously demonstrated that acute administration of beta AR blocker during cardiopulmonary bypass (CPB) in an animal model of coronary artery bypass grafting (CABG) surgery attenuates beta AR desensitization, whereas chronic oral beta-blockade therapy in patients undergoing CABG surgery does not prevent it. Therefore we hypothesized that acute administration of metoprolol during CABG surgery would prevent acute myocardial beta AR desensitization. A placebo-controlled initial phase (n = 72) was performed whereby patients were randomized to either metoprolol 10 mg or placebo immediately before CPB. Then a second dose-finding study was performed where patients received 20 mg (n = 20) or 30 mg (n = 20) of metoprolol. Hemodynamic monitoring, atrial membrane adenylyl cyclase activity, atrial beta AR density, and postoperative outcomes were measured. All groups showed similar decreases in isoproterenol-stimulated adenylyl cyclase activity (13%-24%). Cardiac output remained similar in all 4 groups throughout the intraoperative and postoperative period. In addition, patients receiving metoprolol 20 or 30 mg had less supraventricular arrhythmias 24 h postoperatively compared with patients receiving metoprolol 10 mg or placebo. Therefore, unlike our previous animal model of CABG surgery, metoprolol did not attenuate myocardial beta AR desensitization. IMPLICATIONS: We investigated whether IV metoprolol given during cardiac surgery attenuates myocardial beta-adrenergic receptor (beta AR) desensitization. Although metoprolol did not reduce beta AR desensitization, the incidence of supraventricular arrhythmias was reduced by 75% in patients receiving 20 mg or 30 mg metoprolol.

Adenylyl Cyclases↗
PubMed2004

Profiles of non-victims, escaped victims, continuing victims and new victims of school bullying.

BACKGROUND: Victims of school bullying are known to be at risk in peer relationships and to sometimes use ineffective coping strategies, but little previous research has examined differences among escaped victims, continuing victims and new victims. AIM: A follow-up design compared friendships, behavioural characteristics, victimization experiences and coping strategies of pupils who had 2 years previously answered a questionnaire identifying themselves as victims (V) or non-victims (NV) of school bullying and whose current victim status could be identified. SAMPLE: 406 pupils aged 13-16 years (190 boys, 216 girls): 175 non-victims (NV-NV), 146 escaped victims (V-NV), 27 new victims (NV-V) and 58 continuing victims (V-V). METHOD: Structured interviews were given to pupils, together with the SDQ. Teachers also filled in the SDQ. School records of attendance were obtained. RESULTS: Escaped victims did not differ greatly from non-victims, but had some self-perception of continuing peer relationship difficulties. Continuing victims, irrespective of gender, liked other pupils and breaktime less (but did not dislike other aspects of school), had fewer friends in school (but not outside school), more often missed school (sometimes because of bullying), scored high on problem scales of the SDQ, and were more likely to be involved in bullying others as well as being bullied. New victims tended to resemble continuing victims. Continuing victims did not differ from escaped victims on type of bullying, but new and continuing victims less often reported talking to someone about a specific incident of bullying. Most victims gave mainly victim-related reasons for the bullying having taken place. CONCLUSION: The results are discussed in relation to why some pupils become or continue to be victims in secondary school, and recommendations for anti-bullying procedures in schools designed to help such victims.

Adaptation, Psychological↗
PubMed2003

Depression as a risk factor for mortality after coronary artery bypass surgery.

BACKGROUND: Studies that have shown clinical depression to be a risk factor for cardiac events after coronary artery bypass graft (CABG) surgery have had small sample sizes, short follow-up, and have not had adequate power to assess mortality. We sought to assess whether depression is associated with an increased risk of mortality. METHODS: We assessed 817 patients undergoing CABG at Duke University Medical Center between May, 1989, and May, 2001. Patients completed the Center for Epidemiological Studies-Depression (CES-D) scale before surgery, 6 months after CABG, and were followed-up for up to 12 years. FINDINGS: In 817 patients there were 122 deaths (15%) in a mean follow-up of 5.2 years. 310 patients (38%) met the criterion for depression (CES-D > or =16): 213 (26%) for mild depression (CES-D 16-26) and 97 (12%) for moderate to severe depression (CES-D > or =27). Survival analyses, controlling for age, sex, number of grafts, diabetes, smoking, left ventricular ejection fraction, and previous myocardial infarction, showed that patients with moderate to severe depression at baseline (adjusted hazard ratio [HR] 2.4, [95% CI 1.4-4.0]; p=0.001) and mild or moderate to severe depression that persisted from baseline to 6 months (adjusted HR 2.2, [1.2-4.2]; p=0.015) had higher rates of death than did those with no depression. INTERPRETATION: Despite advances in surgical and medical management of patients after CABG, depression is an important independent predictor of death after CABG and should be carefully monitored and treated if necessary.

Cause of Death↗
PubMed2003

Staphylococcus aureus bacteremia after median sternotomy: clinical utility of blood culture results in the identification of postoperative mediastinitis.

BACKGROUND: Mediastinitis is a complication of coronary artery bypass graft surgery (CABG) that can be difficult to diagnose. This study evaluated the utility of blood culture results in identifying patients with mediastinitis. METHODS AND RESULTS: All unique patients undergoing CABG at our institution over a 60-month study period (n=5500) and all blood cultures performed on these patients or=1 blood culture drawn within 90 days of CABG. Mediastinitis occurred in 46 of 60 (76.7%) patients with blood cultures positive for Staphylococcus aureus, 15 of 126 (11.9%) patients with blood cultures positive for other pathogens, 37 of 669 (5.5%) patients with blood cultures with no growth, and 44 of 4645 (0.9%) patients with no blood cultures obtained. The isolation of S aureus from even 1 blood culture drawn after or=1 blood culture obtained after CABG. CONCLUSIONS: Among patients with blood cultures drawn after CABG, S aureus bacteremia strongly suggests the presence of mediastinitis.

Academic Medical Centers↗
PubMed2003

Low serum magnesium level predicts major adverse cardiac events after coronary artery bypass graft surgery.

BACKGROUND: Despite improved myocardial protection strategies and enhanced surgical techniques, mortality after coronary artery bypass graft surgery (CABG) remains essentially unchanged. This may be because of the increasing age of patients who undergo primary CABG. Magnesium is an important regulator of vascular tone, reperfusion injury, and thrombosis. Therefore, we decided to investigate the relationship between serum magnesium levels and major adverse cardiac events (MACE) after CABG. METHODS: A total of 957 patients undergoing primary CABG were prospectively recruited into the Duke Cardiovascular database and had daily serum magnesium levels measured. Low magnesium was defined as <1.8 mmol/L(-1) at any point during the first 8 days after surgery. Adverse events were defined as Q-wave infarction or death measured 1 year after surgery. A Kaplan-Meier survival analysis was performed, followed by a Cox proportional hazards model, to account for other known predictors of adverse events. RESULTS: In the low magnesium group, 12.3% of patients had adverse events, compared with 9.2% of patients in the normal magnesium group. A serum magnesium level <1.8 mmol/L(-1) decreased the event-free survival rate (2-fold increased risk of death or myocardial infarction at 1 year; hazard ratio 2.0, 95% CI 1.19-3.37). CONCLUSIONS: We demonstrated a robust relationship between low serum magnesium levels after CABG and a 2-fold increased incidence of Q-wave infarction and all-cause mortality rate as long as 1 year after surgery. This relationship is independent of known preoperative and intraoperative predictors of adverse outcomes. This study provides a rationale for a randomized controlled trial of magnesium therapy during CABG.

Aged↗
PubMed2003

The association of lowest hematocrit during cardiopulmonary bypass with acute renal injury after coronary artery bypass surgery.

BACKGROUND: Acute renal injury is a common serious complication of cardiac surgery. Moderate hemodilution is thought to reduce the risk of kidney injury but the current practice of extreme hemodilution (target hematocrit 22% to 24%) during cardiopulmonary bypass (CPB) has been linked to adverse outcomes after cardiac surgery. Therefore we tested the hypothesis that lowest hematocrit during CPB is independently associated with acute renal injury after cardiac surgery. METHODS: Demographic, perioperative, and laboratory data were gathered for 1,404 primary elective coronary bypass surgery patients. Preoperative and daily postoperative creatinine values were measured until hospital discharge per institutional protocol. Stepwise multivariable linear regression analysis was performed to determine whether lowest hematocrit during CPB was independently associated with peak fractional change in creatinine (defined as the difference between the preoperative and peak postoperative creatinine represented as a percentage of the preoperative value). A p value of less than 0.05 was considered significant. RESULTS: Multivariable analyses including preoperative hematocrit and other perioperative variables revealed that lowest hematocrit during CPB demonstrated a significant interaction with body weight and was highly associated with peak fractional change in serum creatinine (parameter estimate [PE] = 4.5; p = 0.008) and also with highest postoperative creatinine value (PE = 0.06; p = 0.004). Although other renal risk factors were significant covariates in both models, TM50 (an index of hypotension during CPB) was notably absent. CONCLUSIONS: These results add to concerns that current CPB management guidelines accepting extreme hemodilution may contribute to postoperative acute renal and other organ injury after cardiac surgery.

Acute Disease↗