European Heart Journal Advance Access originally published online on February 15, 2007
European Heart Journal 2007 28(7):865-871; doi:10.1093/eurheartj/ehl508
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Renal insufficiency and long-term mortality and incidence of myocardial infarction in patients undergoing coronary artery bypass grafting
1 Department of Emergency Medicine, Karolinska University Hospital, 171 76 Stockholm, Sweden
2 Division of Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden
3 Epidemiology, AstraZeneca Research and Development, Mölndal, Sweden
4 Department of Preventive Medicine at Stockholm Centre of Public Health, Karolinska Institute, Stockholm, Sweden
5 Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden
6 Department of Thoracic Surgery, Karolinska University Hospital, Stockholm, Sweden
Received 1 October 2006; revised 10 December 2006; accepted 12 January 2007; online publish-ahead-of-print 15 February 2007.
* Corresponding author. Tel: +46 8 51770000; fax: +46 8 51770990 E-mail address: martin.holzmann{at}karolinska.se
See page 782 for the editorial comment on this article (doi:10.1093/eurheartj/ehm014)
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
|---|
Aims: To evaluate the impact of renal insufficiency (RI) on long-term mortality and incident myocardial infarction (MI) in patients undergoing coronary artery bypass grafting (CABG).
Methods and results: All patients (n = 6575) without dialysis-dependent RI undergoing a first isolated CABG during 1980–1995 at the Karolinska hospital who survived 30 days post-operatively were included. Estimated glomerular filtration rate (eGFR) was related to the incidence of MI and all-cause mortality within 5 years. There were 628 deaths and 496 incident MIs during follow-up. After multivariable adjustment, patients with mild (eGFR 60–90 mL/min), moderate (eGFR 30–60 mL/min), and severe (eGFR <30 mL/min) RI had an increased mortality within 5 years post-CABG; hazard ratio (HR) 1.2 [95% confidence interval (CI) 1.0–1.6], HR 1.8 (95% CI 1.3–2.4), and HR 5.2 (95% CI 3.1–8.6), respectively, compared with patients with normal renal function (eGFR >90 mL/min). In patients with moderate and severe RI, there was an increased incidence of MI; HR 1.5 (95% CI 1.1–2.1) and HR 3.5 (95% CI 1.8–6.8), respectively. There were no gender differences.
Conclusion: Already mild RI predicts late all-cause mortality after coronary artery bypass grafting (CABG), and moderate and severe RI is associated with an increased long-term incidence of MI post-CABG.
Key Words: Renal insufficiency • Coronary artery bypass • Mortality • Myocardial infarction
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
|---|
Patients with renal insufficiency (RI) have an increased risk of cardiovascular events independent of other risk factors.1,2 In patients undergoing coronary artery bypass grafting (CABG), RI is associated with an increased risk of post-operative complications and early death.3–5 Only few studies have assessed the long-term prognostic importance of RI after CABG.6–10 In some long-term studies, renal function has been defined according to the levels of serum creatinine and not to estimated glomerular filtration rate (eGFR).6,7 Since serum creatinine concentrations are influenced by several other factors than the filtration of creatinine, assessment of renal function will be improved by using eGFR. These studies have used a serum creatinine level of at least 1.5 mg/dL (133 µmol/L) to define mild RI.6,7 By using this definition, the true number of patients with RI will be underestimated and renal function will not be classified according to current guidelines.11 Other studies have used eGFR, but definitions of renal function have varied making it difficult to compare and interpret data.8–10
Important aspects not covered by earlier long-term follow-up studies on patients undergoing CABG is what impact RI has on cardiovascular morbidity and to what extent there may be gender differences. Since the majority of patients undergoing CABG are male, and women have lower eGFR at the same age, weight, and serum creatinine levels, it is important to investigate if the impact of RI on long-term prognosis differs between men and women. Thus, to our knowledge, no earlier study has reported the association between RI and long-term risk of incident myocardial infarction (MI) in patients undergoing CABG or reported gender-specific analysis regarding the association between RI and long-term prognosis in this population.
The objective of this study was to investigate to what extent RI assessed by eGFR and classified according to guidelines from the National Kidney Foundation,11 was associated with mortality and incident MI during 5 years after CABG in both men and women without dialysis-dependent RI undergoing a first isolated CABG.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
|---|
Patients
We included all patients without dialysis-dependent RI who underwent a first CABG without any concurrent intracardiac or vascular procedure at the Karolinska Hospital in Stockholm, Sweden between 1980 and 1995 and survived 30 days post-operatively (n = 6575). During this period, 12 patients with end-stage renal failure requiring dialysis underwent CABG at the same hospital. Within 30 days of surgery, 136 (2.0%) patients died. These patients were not included in this study. We have previously reported early mortality in relation to renal function in this cohort.5 All patients were operated on during cardiopulmonary bypass.
Of 6575 patients included in the study, 6377 (97%) had complete data on the following information registered from medical records: age, sex, height, weight, diabetes mellitus (DM), hypertension, hyperlipidaemia, peripheral vascular disease, year of surgery, left main coronary artery stenosis, number of significantly obstructed coronary arteries, prior stroke, prior MI, unstable angina during the current admission, serum creatinine concentration, dialysis-dependent renal failure, and prior cardio-thoracic surgery (CABG, valve procedure or any thoracic vascular surgery). In 1118 (17%) of the patients, information on left ventricular function (LVF) was not available.
The study complies with the Declaration of Helsinki and it was approved by the Ethics Committee at the Karolinska Institute.
Renal function
Serum creatinine was measured at the time of hospital admission, usually the day before surgery. In some elective cases, blood samples were taken before hospital admission, but always within 4 weeks of surgery. Coronary angiography was normally performed several weeks before measurement of serum creatinine. During the entire study period, serum creatinine was analysed by the same method12 and at the same laboratory. eGFR was estimated using the equation of Cockroft and Gault: (140-age) x (weight in kg)/[72 x (serum creatinine in µmol/L/88.4)]for men. In women, the value was multiplied by 0.85.13 RI was defined according to guidelines from the National Kidney Foundation.11 Normal renal function was defined as eGFR of 90 mL/min or more. Mild, moderate, and severe RI were defined as eGFR 60–90, 30–60, and<30 mL/min, respectively. eGFR could not be estimated in 149 (2%) patients due to missing data on serum creatinine (n = 99), weight (n = 12), or serum creatinine and weight (n = 38).
Definitions
Patients were defined as having diabetes if they were taking insulin or oral hypoglycaemic agents and as having hypertension if taking anti-hypertensive medication. Patients taking lipid-lowering agents were defined as having hyperlipidaemia. A coronary artery was defined as significantly obstructed if the luminal diameter was narrowed at least 50%, estimated visually by the physician performing the coronary angiography. Left ventricular function was assessed by pre-operative contrast ventriculography or echocardiography and categorized as normal, reduced, or severely reduced according to the assessment of the thoracic surgeon or the physician performing the ventriculography or the echocardiography. Peripheral vascular disease was defined as a history of exertional claudication and/or prior revascularization to the legs. The patients were classified as having unstable angina if they were admitted to the hospital because of angina at rest, new onset, or accelerated angina within 4 weeks of the operation or angina within 2 weeks of an MI. Body mass index (BMI) was calculated by dividing weight in kilograms by the square of height in metres.
Outcome data
Every person living in Sweden has a unique identification number that was used for record linkage to registers of death and MI, respectively. In the study population, mortality was ascertained during follow-up, as well as prior to surgery, by means of record linkage to the National Cause-of-Death Register, where all the deaths in Sweden are registered with essentially complete coverage. New cases of MI during follow-up were identified by record linkage using information from registers of hospital discharges in Stockholm County (1972–1986) and nationally (1987–2000) as well as from the National Cause-of-Death Register. To avoid one MI being counted for twice, all hospital discharges and deaths with a diagnosis of MI, code 410 in the international classification of diagnosis (ICD) 9 and code I21 in ICD 10 were combined. All MIs recorded within 28 days were considered to reflect the same MI episode.14 This method of case ascertainment has been found to have high sensitivity and positive predictive value in detecting incident cases of MI in a defined population in Sweden.15
Statistical analyses
Patient characteristics for subjects with different levels of eGFR were presented using means with one standard deviation and proportions. Survival during 5 years after CABG in subjects with normal renal function and mild, moderate, or severe RI was analysed using Kaplan–Maier survival curves. The hazard ratio (HR) of death and/or incident MI was estimated crude and in multivariable analysis using Cox's proportional hazards regression. The main purpose of the multivariable analyses was to assess the association between RI and mortality or MI, respectively, while adjusting for potential confounding factors. In order to preserve statistical precision, we aimed towards a parsimonious model including only variables that contributed to reduce confounding. To obtain this, we used a change-in-point-estimate strategy,16 where all variables listed in Table 1 were considered for inclusion in the model and only those that influenced the point estimate of the HR by at least 0.1 when adjusted for in the multivariable analysis were finally used. The set of confounders obtained in this way were similar for different outcomes. The same full model was used at all times for the results presented in this paper including adjustment for age, year of surgery, DM, number of obstructed coronary arteries, hypertension, peripheral vascular disease, unstable angina, and left ventricular function. Estimates of HR were accompanied by asymptotic 95% confidence intervals (CI). To assess the proportional hazards assumption, we examined log cumulative hazard plots, the Nelson–Aalen cumulative hazard function, and martingale residuals for the entire study period and separate by period of surgery. These examinations did not indicate violations of the proportional hazards assumption. In the multivariable analysis, age was included in the model as a continuous variable and other variables in general as dichotomous representing presence or absence of the characteristic. Year of surgery was subdivided into the categories 1980–1984, 1985–1989, and 1990–1995. Left ventricular function was categorized as normal, reduced, or severely reduced. Adjustment for confounding from age did not appear to improve when age was entered into the model with a quadratic term. The Cochran–Armitage test for trend was applied to evaluate the change in risk factors, mortality, and MI, respectively, by ordinal category of eGFR.
|
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
|---|
Patient characteristics
There were 1249 (19%) women and 5326 (81%) men in the study population. Defining renal function according to current guidelines,11 normal renal function was present in 29% of the patients. Forty-nine percent had mild, 21% moderate, and 1% severely reduced renal function (Table 1). With increasing degree of RI, the patients were older, had lower BMI, were more likely to have unstable angina, hypertension, a history of MI or stroke, peripheral vascular disease, DM, three-vessel disease, left main coronary artery stenosis, and severely reduced LVF. In 17% (n = 1118) of the patients, information on LVF was not available (Table 1). Among these patients, most characteristics available did not differ compared with patients with information on LVF.
There were 299 (5%) patients with MI within 30 days before surgery. Sixty-two of these patients had their MI within 7 days before undergoing CABG. Only 263 (4%) patients underwent surgery within 24 h of coronary angiography.
During the 15 year study period, the proportions of mild, moderate, and severe RI changed from 48, 12, and 1%, respectively, during 1980–1984 to 27, 25, and 1%, respectively, during 1990–1995. The average age at surgery was 64 for women and 61 for men, and increased during the study period from 58 and 56 years during 1980–1984 to 66 and 64 years during 1990–1995.
Mortality and MI
There were 628 (10%) deaths and 496 (8%) incident fatal or non-fatal MIs within 5 years of CABG. Of the patients experiencing an MI, 176 (35%) died within 30 days of the event. Among patients (n = 149) without information on eGFR, 14 (10%) died and 11 (7%) had a fatal or non-fatal MI during follow-up. In total, 908 (14%) patients reached the combined endpoint of death or non-fatal MI during follow-up. There were 19 (13%) patients with this combined endpoint among patients with missing information on eGFR.
We found a substantially lower 5 year survival in patients with severe RI compared with those with better renal function (Figure 1). In patients with mild and moderate RI, survival after 5 years was also reduced to 91 and 85%, respectively, compared with those with normal renal function, 94%. These differences persisted after adjustment for potential confounding factors; and with the application of a more differentiated classification of RI, long-term mortality increased gradually with decreasing eGFR (Figure 2).
|
|
90 mL/min.At all levels of RI, an increased mortality within 5 years was present even after multivariable adjustment (Table 2). Compared with patients with normal renal function, those with moderate and severe RI had almost two and five times increased risk of dying within 5 years of surgery, respectively. In addition, the incidence of MI was increased in patients with moderate and severe RI. Similar results were obtained in analyses of the combined endpoint death or non-fatal MI. An estimated GFR <60 mL/min was associated with an increased incidence of non-fatal MI or death compared with an estimated GFR >60 mL/min, in both men and women (Table 3). In terms of relative risk, RI was a strong risk factor of long-term mortality compared with other risk factors also influencing the long-term prognosis after surgery (Table 4).
|
|
|
During all three time periods, 1980–1985, 1986–1990, and 1991–1995, eGFR <60 mL/min was associated with a higher mortality or MI incidence within 5 years; HR 1.6, (95% CI 1.0–2.7), HR 1.6 (95% CI 1.1–2.5), and HR 1.6 (95% CI 1.1–2.2), respectively, compared with eGFR >60 mL/min.
In analyses of eGFR as a continuous variable, each 10 mL/min increase in eGFR decreased the risk of death within 5 years of surgery by 12%; HR 0.88 (95% CI 0.84–0.93) per 10 mL/min increase in eGFR after multivariable adjustment for confounders.
Mortality within 5 years of surgery according to quartiles of serum creatinine was also assessed. Serum creatinine was <84, 85–96, 97–109, and >110 µmol/L, respectively, in quartile one to four. The relative risk of death for patients in quartile two, three, and four compared with quartile one was, HR 1.0 (95% CI 0.8–1.3), HR 1.1 (95% CI 0.9–1.5), and HR 1.5 (95% CI 1.2–1.9), respectively, after multivariable adjustment for confounders.
Receiver operator characteristics curves were used to analyse the sensitivity and specificity of eGFR and serum creatinine, respectively, for the identification of long-term deaths after CABG. The areas under the curves were 0.756 for eGFR and 0.761 for serum creatinine, respectively, yielding no statistically significant difference.
Among patients with normal renal function who died during follow-up, 63% died of cardiovascular causes including stroke. The corresponding figures for mild, moderate, and severe RI were not much different, 67, 71, and 64%, respectively. Cancer was the underlying cause of death among 20% of patients with normal renal function, 15% of patients with mild or moderate RI, and among 3% of patients with severe RI. Among patients with severe RI, one (3%) had renal failure as underlying cause of death. Among those with moderate and mild RI, the corresponding figure was 1% in each category.
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
|---|
Our results demonstrate that already mild RI predicts long-term mortality and moderate and severe RI predicts long-term risk of MI in patients undergoing CABG. Our data are consistent with results in previous studies on long-term mortality in patients with RI undergoing CABG.6–10
A majority of patients undergoing CABG are male. In our study, there were 19% women included. At the same age, weight, and level of serum creatinine women have a lower eGFR while there may be a different qualitative relationship between renal function and risk of future cardiovascular disease in women. However, the association between RI and long-term outcomes were similar in both men and women. This indicates that RI as a determinant of future MI and death after CABG is as important in women as in men.
Earlier studies have demonstrated RI to be a strong predictor of mortality within 30 days of CABG.3–5 We have shown calculated creatinine clearance to be superior to serum creatinine concentrations as a predictor of early outcomes in this study population.5 Post-operatively, patients with RI have an increased risk of acute renal failure, bleeding, stroke, and prolonged ventilation.3,4 Patients who develop acute renal failure and require haemodialysis have a markedly increased rate of early mortality.17
We excluded patients who died within 30 days of surgery, since it may be other mechanisms that cause the long-term compared with early increase in risk of an adverse outcome in patients with RI. By doing this, our cohort essentially consisted of patients with stable coronary heart disease (CHD). Other physicians than cardiologists often care for these patients. Family doctors often manage them, and information to other parts of the medical community in addition to cardiologists, internists, and thoracic surgeons on the predictive power of RI on future death and MI is needed. Our data indicate that RI should be regarded as an important risk factor for death and MI alongside hyperlipidaemia, smoking, diabetes, and hypertension, in patients who already have or is at high risk of developing CHD. We think that in view of emerging evidence, RI should also be considered in future risk prediction models. This is not the case in the recently developed European SCORE risk prediction system.18
It is unclear by which mechanisms RI influence long-term risk in patients with CHD. For those surviving the initial post-operative period, RI may accelerate atherosclerosis increasing the risk of new cardiovascular events. RI may be a marker for undiagnosed vascular disease or a marker for the severity of vascular damage. It is also possible that in the presence of RI, traditional risk factors such as smoking, hyperlipidaemia, hypertension, and DM will have a different qualitative relationship with cardiovascular events.19
With increasing degree of RI, patients were older and had more comorbidity compared with patients with normal renal function. Adjustment, in particular, for age but also other confounders influenced HRs substantially, but RI remained strongly associated with long-term MI and death.
Some studies have suggested that patients with RI are less likely to receive medication or therapies known to lower the risk of a future cardiovascular event such as betablockers, angiotensin-converting-enzyme inhibitors, thrombolytic therapy, and percutaneous coronary intervention.20,21 However, patients with RI do have similar benefit of these therapies as patients with normal renal function.22,23
Our patients were recruited during a relatively long period, 15 years. During this period, the average age at surgery increased considerably and moderate or severe RI became more common. When dividing this period into three, we found that our results were consistent throughout the entire period. This may indicate that our results are robust to changes or differences in patient characteristics and medication.
A growing number of the general population has kidney disease. In the US, an estimated 11% of the adult population have chronic kidney disease.11 The number of patients with kidney failure treated by dialysis or kidney transplantation is expected to double between 1998 and 2010.23 A serum creatinine level of 1.5 mg/dL (133 µmol/L) has often been used as the cut-off between normal renal function and RI in cardiovascular studies. Using this definition, 94% of our patient population would have had normal renal function and only 6% RI. In the present study, we estimated GFR and 71% of the patients had decreased GFR (eGFR <90 mL/min) and 21% had chronic kidney disease defined as eGFR <60 mL/min.11 Only 29% had normal renal function. This demonstrates that the prevalence of RI is greatly underestimated if serum creatinine level instead of eGFR is used to define renal function.
We also used a more differentiated categorization of renal function than suggested in guidelines and found that mortality increased gradually. Among patients with moderate RI, mortality almost doubled among those with eGFR 30–45 mL/min compared with those with eGFR 45–60 mL/min. This may indicate that the definition of renal function in current guidelines11 may be too crude to fully capture the long-term risk of death and MI associated with RI in patients post-CABG.
Study strengths and limitations
A strength of the present study was that all patients undergoing a first isolated CAB during a time period of 15 years at our institution were included. In addition, during the entire study period, serum creatinine concentrations were analysed at one laboratory by the same method,12 assuring us consistent assessment of renal function. The Swedish National Cause-of-Death Register has a high completeness and there was essentially no loss of deaths during the follow-up. We identified new cases of MI in the study population using information from national or regional registers of hospital discharges and deaths. The diagnostic information was based on the routinely recorded hospital discharges and death certificates, in which no uniform diagnostic criteria were applied. The present study covers a 15 year period and during this time, there were changes in the application of diagnostic criteria of MI in Sweden, in particular, by an increased use of more sensitive enzymes. Most patients in the present study were living in Stockholm and during the study period similar diagnostic criteria for MI based on symptoms, ECG findings, and typical enzyme changes were employed at all emergency hospitals in Stockholm. The diagnostic quality at hospitals in Stockholm has been evaluated in repeated studies and found to be high during the study period.24,25 In spite of this, some events were unrecognized, including silent cases, and some were erroneously diagnosed as MI. It is unlikely that any misclassification of MI was related to RI and the most probable effect is a dilution of observed associations.
We were also consistent in our definition of RI following current guidelines.11
Information on smoking status was not available to us. However, in earlier studies on the prognostic importance of RI after CABG, smoking has not been more prevalent among patients with RI compared with those with normal renal function.8,9 Since we only knew if the patients had hypertension and hyperlipidaemia or not, and the level of blood pressure or lipids were unknown, we could not fully adjust for these confounders. It is also possible that other confounding factors were either only partially controlled for or unknown to us. Thus, it is likely that some residual confounding influenced the associations observed. In view of the strong and graded association between RI and mortality and MI, it seems unlikely that this can fully explain our main results. Furthermore, we do not know if patients with RI received cardio- or renoprotective medication as statins, betablockers, aspirin, and angiotensin- converting- enzyme inhibitors or other cardiovascular drugs to a lesser extent than those with normal renal function, which has been reported.20
Coronary angiography is known to affect serum creatinine levels transiently. In patients with unstable angina, we did not know the timing of the angiogram to the measurement of creatinine. Relying on one measurement of serum creatinine may therefore lead to misclassification of renal function. Most patients had stable CHD and the angiography was performed several weeks before blood samples were taken and therefore not affecting the level of creatinine recorded. A misclassification of renal function by a transient rise in creatinine levels tend to underestimate relative risk estimates for moderate or severe RI and is thus unlikely to explain our findings.
Post-operative creatinine levels were not known to us. Thus, we could not assess the importance of post-operative worsening renal function on long-term prognosis.
|
Conclusions |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
|---|
RI is common among patients undergoing CABG. Already mild RI is associated with increased long-term mortality and moderate or severe RI with incident MI within 5 years of CABG. In both men and women undergoing CABG, moderate and severe RI is a long-term predictor of mortality and MI.
|
Acknowledgements |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
|---|
We are grateful to Christian Unge, Henrik Overödder, and Björn Törnkvist for collecting information from the medical records. Financial support was provided by EXPO 95 of the Stockholm County Council, the Ansgarius Foundation, and the Swedish Heart-and-Lung Foundation.
Conflict of interest: none declared.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionConclusionsAcknowledgementsReferences |
|---|
- Hall WD. (1999) Abnormalities of kidney function as a cause and a consequence of cardiovascular disease. Am J Med Sci 317:176–182.[CrossRef][ISI][Medline]
- Foley RN, Parfrey PS, Sarnak MJ. (1998) Clinical epidemiology of cardiovascular disease in chronic renal disease. Am J Kidney Dis 32:S112–S119.[ISI][Medline]
- Anderson RJ, O'Brien M, Mawhinney S, Villanueva CB, Moritz TE, Sethi GK, Henderson WG, Hammermeister KE, Grover FL, Shroyer AL. (1999) Renal failure predisposes patients to adverse outcome after coronary artery bypass surgery. VA Cooperative Study #5. Kidney Int 55:1057–1062.[CrossRef][ISI][Medline]
- Durmaz I, Büket S, Atay Y, Yagdi T, Ozbaran M, Boga M, Alat I, Guzelant A, Basarir S. (1999) Cardiac surgery with cardiopulmonary bypass in patients with chronic renal failure. J Thorac Cardiovasc Surg 118:306–315.
[Abstract/Free Full Text] - Holzmann M, Ahnve S, Hammar N, Jörgensen L, Klerdal K, Pehrsson K, Ivert T. (2005) Creatinine clearance and risk of early mortality in patients undergoing coronary artery bypass grafting. J Thorac Cardiovasc Surg 130:746–752.
[Abstract/Free Full Text] - Szczech LA, Best PJ, Crowley E, Brooks MM, Berger PB, Bittner V, Gersh BJ, Jones R, Califf RM, Ting HH, Whitlow PJ, Detre KM, Holmes D. Bypass Angioplasty Revascularization Investigation (BARI) Investigators. (2002) Outcomes of patients with chronic renal insufficiency in the bypass angioplasty revascularization investigation. Circulation 105:2253–2258.
[Abstract/Free Full Text] - Nakayama Y, Sakata R, Ura M, Itoh T. (2003) Long-term results of coronary artery bypass grafting in patients with renal insufficiency. Ann Thorac Surg 75:496–500.
[Abstract/Free Full Text] - Lok CE, Austin PC, Wang H, Tu J. (2004) Impact of renal insufficiency on short- and long-term outcomes after cardiac surgery. Am Heart J 148:430–438.[CrossRef][ISI][Medline]
- Zakeri R, Freemantle N, Barnett V, Lipkin GW, Bonser RS, Graham TR, Rooney SJ, Wilson IC, Cramb R, Keogh BE, Pagano D. (2005) Relation between mild renal dysfunction and outcomes after coronary artery bypass grafting. Circulation 112:Suppl. II-270–I-275.[Medline]
- Hillis GS, Croal BL, Buchnan KG, El-Shafei H, Gibson G, Jeffrey RR, Millar CGM, Prescott GJ, Cuthbertson BH. (2006) Renal function and outcomes from coronary artery bypass grafting. Impact on mortality after a 2.3-year follow-up. Circulation 113:1056–1062.
[Abstract/Free Full Text] - National Kidney Foundation. (2002) K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification and stratification. Am J Kidney Dis 39:Suppl. 2S1–S246.[CrossRef][ISI][Medline]
- Bartels H, Böhmer M, Heierli C. (1972) Serum creatinine determination without protein precipitation (german). Clin Chim Acta 37:193–197.[CrossRef][ISI][Medline]
- Cockcroft DW and Gault MH. (1976) Prediction of creatinine clearance from serum creatinine. Nephron 16:31–41.[ISI][Medline]
- Hammar N, Nerbrand C, Ahlmark G, Tibblin G, Tsipogianni A, Johansson S, Wilhelmsen L, Jacobsson S, Hansen O. (1991) Identification of cases of myocardial infarction: hospital discharge data and mortality data compared to myocardial infarction community registers. Int J Epidemiol 20:114–120.
[Abstract/Free Full Text] - Hammar N, Alfredsson L, Rosén M, Spetz C-L, Kahan T, Ysberg A-S. (2001) A national record linkage to study acute myocardial infarction incidence and case fatality in Sweden. Int J Epidemiol 30:Suppl. 1S30–S34.
[Free Full Text] - Rothman K and Greenland S. (1998) Modern Epidemiology. 2nd ed Lippincott-Raven.
- Chertow GM, Lazarus JM, Christiansen CL, Cook EF, Hammermeister KE, Grover F, Daley J. (1997) Preoperative renal risk stratification. Circulation 95:878–884.
[Abstract/Free Full Text] - Conroy RM, Pyörälä K, Fitzgerald AP, Sans S, Menotti A, De Backer G, De Bacquer D, Ducimetière P, Jousilahti P, Keil U, Njølstad I, Oganov RG, Thomsen T, Tunstall-Pedoe H, Tverdal A, Wedel H, Whincup P, Wilhelmsen L, Graham IM. (2003) On behalf of the SCORE project group. Estimation of ten-year risk of fatal cardiovascular disease in Europe: the SCORE project. Eur Heart J 24:987–1003.
[Abstract/Free Full Text] - Sarnak MJ, Levey AS, Schoolwerth AC, Coresh J, Culleton B, Hamm LL, McCullough PA, Kasiske BL, Kelepouris E, Klag MJ, Parfrey P, Pfeffer M, Raij L, Spinosa DJ, Wilson PW. (2003) Kidney disease as a risk factor for development of cardiovascular disease: a statement from the American Heart Association Councils on Kidney in Cardiovascular Disease, High Blood Pressure Research, Clinical Cardiology, and Epidemiology and Prevention. Circulation 108:2154–2169.
[Free Full Text] - Beattie JN, Soman SS, Sandberg KR, Yee J, Borzak S, Garg M, McCullough PA. (2001) Determinants of mortality after myocardial infarction in patients with advanced renal dysfunction. Am J Kidney Dis 37:1191–1200.[ISI][Medline]
- Tonelli M, Bohm C, Pandeya S, Gill J, Levin A, Kiberd BA. (2001) Cardiac risk factors and the use of cardioprotective medications in patients with chronic renal insufficiency. Am J Kidney Dis 37:484–489.[ISI][Medline]
- Reddan DN, Szczech LA, Tuttle RH, Shaw LK, Jones RH, Schwab SJ, Smith MS, Califf RM, Mark DB, Owen WF Jr. (2003) Chronic kidney disease, mortality, and treatment strategies among patients with clinically significant coronary artery disease. J Am Soc Nephrol 14:2373–2380.
[Abstract/Free Full Text] - Szczech LA, Reddan DN, Owen WF, Califf R, Racz M, Jones RH, Hannan EL. (2001) Differential survival after coronary revascularization procedures among patients with renal insufficiency. Kidney Int 60:292–299.[CrossRef][ISI][Medline]
- Hammar N, Larsen FF, deFaire U. (1994) Are geographical differences and time trends in myocardial infarction incidence in Sweden real? Validity of hospital discharge diagnoses. J Clin Epidemiol 47:685–693.[CrossRef][ISI][Medline]
- Linnersjö A, Gustavsson A, Reuterwall C, Hammar N. (2000) Recent time trends in acute myocardial infarction in Stockholm, Sweden. Int J Cardiol 76:17–21.[CrossRef][ISI][Medline]
CiteULike 
Connotea 
Del.icio.us What's this?
Related articles in EHJ:
- Renal function, revascularization and risk
- Graham S. Hillis, Brian H. Cuthbertson, and Bernard L. Croal
EHJ 2007 28: 782-784.[Extract] [Full Text]
This article has been cited by other articles:
|
|
 |
|
  J. R. Brown, R. P. Cochran, T. A. MacKenzie, A. P. Furnary, K. S. Kunzelman, C. S. Ross, C. W. Langner, D. C. Charlesworth, B. J. Leavitt, L. J. Dacey, et al. Long-term survival after cardiac surgery is predicted by estimated glomerular filtration rate. Ann. Thorac. Surg., July 1, 2008; 86(1): 4 - 11. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O.-P. Kangasniemi, M. A. A. Mahar, E. Rasinaho, A. Satomaa, V. Tiozzo, M. Lepojarvi, and F. Biancari Impact of estimated glomerular filtration rate on the 15-year outcome after coronary artery bypass surgery Eur. J. Cardiothorac. Surg., February 1, 2008; 33(2): 198 - 202. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. S. Hillis, B. H. Cuthbertson, and B. L. Croal Renal function, revascularization and risk Eur. Heart J., April 1, 2007; 28(7): 782 - 784. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||