|
|
||||||||||
|
J Am Coll Cardiol, 2006; 47:809-816, doi:10.1016/j.jacc.2005.09.060
(Published online 6 February 2006). © 2006 by the American College of Cardiology Foundation |
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||



* Duke Clinical Research Institute, Durham, North Carolina
University of Kentucky, Lexington, Kentucky
Cleveland Clinic Foundation, Cleveland, Ohio
University of Alberta, Edmonton, Alberta, Canada
|| Universitaire Ziekenhuizen Leuven, Leuven, Belgium.
Manuscript received February 17, 2005; revised manuscript received August 26, 2005, accepted September 9, 2005.
* Reprint requests and correspondence: Dr. Sunil V. Rao, The Duke Clinical Research Institute, P.O. Box 17969, Durham, North Carolina 27715. (Email: sunil.rao{at}duke.edu).
| Abstract |
|---|
|
|
|---|
BACKGROUND: There are limited data on the relative utility of either scale at predicting clinical outcomes in patients with nonST-segment elevation acute coronary syndromes (ACS).
METHODS: Pooled data from two randomized trials of patients with ACS (n = 15,454) were analyzed to determine the association between TIMI and GUSTO bleeding and 30-day and 6-month death/myocardial infarction (MI) using Cox proportional hazards modeling that included bleeding as a time-dependent covariate.
RESULTS: There was a stepwise increase in the adjusted hazard of 30-day death/MI with worsening GUSTO bleeding (hazard ratio [95% confidence interval], GUSTO mild 1.20 [1.05 to 1.37]; moderate 3.28 [2.88 to 3.73]; severe 5.57 [4.33 to 7.17]), and an increased risk with all three levels of TIMI bleeding (TIMI minimal 1.84 [1.63 to 2.08]; TIMI minor 1.64 [1.31 to 2.04]; major 1.45 [1.23 to 1.70]). When both bleeding scales were included in the same model, the risk with GUSTO bleeding persisted; however, the association between TIMI bleeding and outcome was no longer significant.
CONCLUSIONS: Both scales identify ACS patients with bleeding complications at risk for adverse outcomes. In a model that included both definitions, the risk with GUSTO bleeding persisted while the risk with TIMI bleeding did not. This suggests that bleeding assessed with clinical criteria is more important than that assessed by laboratory criteria in terms of outcomes. Future clinical trials should consider using a combination of the GUSTO bleeding scale and the need for transfusion to assess bleeding complications.
| |||||||||
| Methods |
|---|
|
|
|---|
Concomitant treatment with aspirin (dose ranges between 80 and 325 mg daily) and antithrombin agents was recommended by protocol in both trials. The use of other medications and procedures was at the discretion of the treating physicians.
Definitions and end points.
Bleeding
The TIMI bleeding classification is a laboratory-based scale (7) while the GUSTO bleeding classification is a clinically based scale (8) (Table 1). The TIMI definition of bleeding uses four categories: major, minor, minimal, and none. The GUSTO bleeding definition also uses four categories: severe or life-threatening, moderate, mild, and none. The PURSUIT investigators used both definitions to classify bleeding events. The PARAGON investigators defined bleeding complications as major or life-threatening, and intermediate. Major or life-threatening bleeding was defined as any intracranial hemorrhage or bleeding leading to hemodynamic compromise requiring intervention. Intermediate bleeding was defined as bleeding requiring transfusion or a decrease in hemoglobin 5 g/dl or more (or decrease in hematocrit
15% when hemoglobin was unavailable). For the purpose of this analysis, the TIMI and GUSTO classifications were reconstructed from the detailed clinical data ().
|
End points
The primary end point of our study was the occurrence of death or recurrent myocardial infarction (MI) at 30 days. The secondary end point was the occurrence of death or recurrent MI at six months. Myocardial infarction was defined according to the protocol of each trial (5,6). All death and MI events for each trial were adjudicated by an independent blinded events committee.
Statistical analysis. Patients were grouped according to the presence or absence of a bleeding event. Patients who experienced a bleeding event were further classified based on bleeding severity according to the TIMI and GUSTO scales. Categorical variables are expressed as percentages, and continuous variables are expressed as medians and interquartile ranges. Baseline characteristics were compared using chi-square tests for categorical variables and the non-parametric Kruskal-Wallis test for continuous variables. Baseline differences with p values <0.01 were considered significant.
We compared unadjusted rates of the primary and secondary end points among patients with no bleeding and those within the various categories of TIMI and GUSTO bleed severity. To determine the association between bleeding severity as defined by the two scales and the primary and secondary outcomes, we constructed separate models for each bleeding definition. Because bleeding is a post-randomization event that can change over time, and can influence and be influenced by treatments (e.g., procedures) and adverse events (e.g., MI), both models incorporated bleeding as a time-dependent covariate in a Cox regression. This technique minimizes confounding by considering only those bleeding events that transpired before the occurrence of the end points (9). Variables entered into both models were based on a comprehensive set of baseline variables from a validated model of outcome among patients with nonST-segment elevation ACS (10) (c-index = 0.81) and included patient characteristics, presenting signs and symptoms, and treatments, including blood transfusion.
The first model incorporated TIMI bleed severity as a time-dependent covariate and used "no TIMI bleeding" as the reference. The second model incorporated GUSTO bleed severity as a time-dependent covariate and used "no GUSTO bleeding" as the reference. Due to the potential influence of blood transfusion on outcomes (11), we repeated the analysis after adjusting for transfusion by creating a dichotomous time-dependent variable that coded transfusion of at least 1 U of blood. We also repeated the analysis by constructing a model that included both bleeding scales as time-dependent covariates. Additional models were generated to evaluate the effect of each bleed scale in the presence or absence of the other scale. The models were adjusted for baseline covariates and included the scale of interest (e.g., the GUSTO scale) plus an indicator for any bleed according to the other scale (e.g., any type of TIMI bleed) versus no bleed according to the other scale (e.g., no TIMI bleed of any sort). Another set of models included the interaction of these two variables. Because coronary artery bypass surgery (CABG) can influence the severity of bleeding as well as outcomes, we repeated the analysis again for the entire patient cohort with censoring at the time of CABG. Finally, we used interaction terms to explore the effect of patient age, gender, weight, and renal function on TIMI and GUSTO bleeding levels in predicting short- and intermediate-term death or MI. All analyses were performed using SAS Version 8.2 (SAS Institute, Cary, North Carolina).
Ethics of protocol. The institutional review boards of all participating institutions reviewed and approved the protocols of the PURSUIT and PARAGON B trials. All enrolled patients gave written informed consent.
| Results |
|---|
|
|
|---|
With regard to TIMI bleeding, 12.7% of patients experienced a TIMI minimal bleed, 8.5% of patients experienced a TIMI minor bleed, and 8.2% experienced a TIMI major bleed. Table 1 shows the baseline characteristics of the patients who developed TIMI bleeding by the severity of the bleeding event. There were significant differences in baseline characteristics across the TIMI bleeding categories so that patients with a TIMI minor bleed were older, more often of non-white race and female, more often had cardiac risk factors, and were sicker at presentation compared with those having either a TIMI minimal or major bleed. In addition, a higher proportion of patients with TIMI minor bleeding had undergone in-hospital PCI compared with those with TIMI minimal or major bleeding. In contrast, a higher proportion of patients who experienced a TIMI major bleed had prior hyperlipidemia, prior MI, prior congestive heart failure, and prior stroke. A higher proportion of patients with TIMI minimal bleeding had undergone cardiac catheterization and CABG compared with those who experienced TIMI minor or major bleeding. Approximately one-third of the patients with TIMI minimal, minor, and major bleeding underwent blood transfusion during the hospitalization. Significantly more patients with TIMI bleeding who underwent CABG were transfused compared with patients with TIMI bleeding who did not undergo CABG (18% vs. 4.6%, p < 0.001).
The proportion of patients with GUSTO mild, moderate, and severe bleeding was 19.2%, 11.4%, and 1.2%, respectively. Table 2 shows the baseline characteristics of patients by worsening GUSTO bleed severity. As the GUSTO bleeding severity worsened, there was a gradient of increasing age, increasing proportion of patients of non-white race, and an increasing proportion of patients with hypertension, diabetes mellitus, prior MI, prior stroke, prior PCI, chronic renal insufficiency, and patients presenting with higher Killip class and higher heart rate. Patients who experienced a GUSTO moderate bleed had undergone cardiac catheterization and/or CABG during hospitalization more often than those experiencing mild or severe bleed, while patients who experienced a GUSTO mild bleed had undergone PCI more often than those who experienced a moderate or severe bleed. Very few patients with GUSTO mild bleeding underwent blood transfusion while a large proportion of patients with GUSTO moderate and severe bleeding received blood transfusion. Significantly more patients with GUSTO bleeding who underwent CABG received transfusion compared with patients with GUSTO who did not undergo CABG (53.5% vs. 10.0%, p < 0.001).
|
|
|
|
|
| Discussion |
|---|
|
|
|---|
Our study has important implications for both clinical care and clinical research. Both bleeding definitions were developed to classify bleeding complications of thrombolytic therapy (7,8), and have not been previously validated in the setting of nonST-segment elevation ACS. Other investigators have explored the incidence and predictors of bleeding complications in this population (2,12,13), but the bleeding definitions used varied across studies, and outcomes were not specifically examined. Our results add to these previous studies by demonstrating that that bleeding complications, regardless of severity, are associated with worse clinical outcomes among patients with acute ischemic heart disease in whom thrombolytic therapy is not used. While this increased risk persisted for all levels of GUSTO bleeding even after adjusting for blood transfusion, it did not persist for TIMI bleeding after accounting for transfusion. Because one difference between the TIMI and GUSTO scales is whether transfusion is necessary, our results suggest that patients who experience TIMI bleeding who do not require transfusion (i.e., asymptomatic decreases in hemoglobin) are not at risk for adverse outcomes. Therefore, liberal use of blood transfusion in these patients may expose them to the risks of transfusion (11,14) without any clear benefit. These data also provide support for clinical practice guidelines that discourage the use of blood transfusions in patients who are clinically stable regardless of their nadir hemoglobin or hematocrit value (15).
Although our study is the first to provide evidence for the association between bleeding as measured by both the GUSTO and TIMI bleeding classifications and clinical outcomes in the setting of nonST-segment elevation ACS, these definitions have been used either alone or in combination in cardiovascular clinical trials over the last two decades (5,1624). This has resulted in wide variation in the rates of bleeding complications that have been reported with various antithrombotic agents. For example, in the Superior Yield of the New Strategy of Enoxaparin, Revascularization and Glycoprotein IIb/IIIa Inhibitors (SYNERGY) trial of enoxaparin versus unfractionated heparin, the rate of TIMI major bleeding was 9.7% among patients assigned to enoxaparin, but the rate of GUSTO severe bleeding was only 2.7% (24). In the context of this disparity, our study suggests that the guidelines for measuring bleeding among patients with ACS (4) should be amended to include a more optimal metrica combination of the clinically-based GUSTO scale and need for blood transfusion. Bleeding complications with limited prognostic value as determined by the laboratory-based TIMI scale may continue to have a role in guiding dosing decisions for new anticoagulants that are in development.
Study limitations. Our study has some limitations. First, our study was not designed to evaluate the definitions of bleeding per se. Rather, we sought to delineate the association between bleeding defined by two of the most commonly used bleeding scales and clinical outcomes. Second, our results could be the result of ascertainment bias. The identification of TIMI bleeding events could be limited if hemoglobin or hematocrit values are not obtained. This could lead to an underestimation of the number of TIMI bleeds. Third, our study was a post-hoc analysis of pooled clinical trial data that was collected prospectively. Therefore, despite our robust statistical methods, there could be residual confounding. Fourth, we reclassified bleeding events from the PARAGON B trial into the relevant GUSTO and TIMI categories on the basis of the detailed clinical data that was available. Nevertheless, because PARAGON B used a definition of bleeding that was slightly modified from either the GUSTO or TIMI classification, this may limit our ability to draw firm conclusions on the relationship between both definitions and clinical outcomes. Fifth, despite the strength of the associations we found, we cannot definitively state causality between bleeding and death or MI due to the retrospective nature of our study. Finally, our study population was comprised of patients enrolled in clinical trials and may not be fully representative of patients seen in clinical practice (25). Because the study population did not include higher-risk patients, such as those who are older and have more comorbidities, the risks may be underestimated.
Conclusions. In conclusion, the results of our study indicate that both the GUSTO and TIMI scales identify patients with bleeding complications who are at risk for short- and intermediate-term death or MI. However, after adjusting for transfusion and when both scales were included in the same model, the increased risk with worsening GUSTO bleeding persisted while the risk with TIMI bleeding did not. These results suggest that asymptomatic decreases in hemoglobin and/or hematocrit that do not require transfusion may not be associated with a worse prognosis. Therefore, the issue of whether asymptomatic decreases in hemoglobin or hematocrit require aggressive transfusion deserves further scrutiny. This study also suggests that a combination of the GUSTO scale and need for transfusion should be used to assess bleeding complications in subsequent clinical trials of patients with ACS.
| Appendix |
|---|
|
|
|---|
| Footnotes |
|---|
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
R. J. Applegate, M. T. Sacrinty, M. A. Kutcher, F. R. Kahl, S. K. Gandhi, R. M. Santos, and W. C. Little Trends in Vascular Complications After Diagnostic Cardiac Catheterization and Percutaneous Coronary Intervention Via the Femoral Artery, 1998 to 2007 J. Am. Coll. Cardiol. Intv., June 1, 2008; 1(3): 317 - 326. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-P. Bassand Bleeding and transfusion in acute coronary syndromes: a shift in the paradigm Heart, May 1, 2008; 94(5): 661 - 666. [Full Text] [PDF] |
||||
![]() |
H. L. Dauerman Percutaneous Coronary Intervention Pharmacology From a Triangle to a Square. J. Am. Coll. Cardiol., February 19, 2008; 51(7): 698 - 700. [Full Text] [PDF] |
||||
![]() |
P. B. Berger and S. V. Manoukian Bleeding Is Bad.... Isn't It? Circulation, December 11, 2007; 116(24): 2776 - 2778. [Full Text] [PDF] |
||||
![]() |
S. V. Rao, J. A. Eikelboom, C. B. Granger, R. A. Harrington, R. M. Califf, and J.-P. Bassand Bleeding and blood transfusion issues in patients with non-ST-segment elevation acute coronary syndromes Eur. Heart J., May 2, 2007; 28(10): 1193 - 1204. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. V. Manoukian, F. Feit, R. Mehran, M. D. Voeltz, R. Ebrahimi, M. Hamon, G. D. Dangas, A. M. Lincoff, H. D. White, J. W. Moses, et al. Impact of Major Bleeding on 30-Day Mortality and Clinical Outcomes in Patients With Acute Coronary Syndromes: An Analysis From the ACUITY Trial J. Am. Coll. Cardiol., March 27, 2007; 49(12): 1362 - 1368. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. W. Mahaffey and R. A. Harrington Optimal Timing for Use of Glycoprotein IIb/IIIa Inhibitors in Acute Coronary Syndromes: Questions, Answers, and More Questions JAMA, February 14, 2007; 297(6): 636 - 639. [Full Text] [PDF] |
||||
![]() |
J. W. Eikelboom and J. Hirsh Bleeding and management of bleeding Eur. Heart J. Suppl., October 1, 2006; 8(suppl_G): G38 - G45. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. W. Eikelboom, S. R. Mehta, S. S. Anand, C. Xie, K. A.A. Fox, and S. Yusuf Adverse Impact of Bleeding on Prognosis in Patients With Acute Coronary Syndromes Circulation, August 22, 2006; 114(8): 774 - 782. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | SUBSCRIPTIONS | CURRENT ISSUE | PAST ISSUES | CARDIOSOURCE | SEARCH | HELP | FEEDBACK |