Gender Differences in Outcomes After Primary Angioplasty Versus Primary Stenting With and Without Abciximab for Acute Myocardial Infarction
http://www.100md.com
循环学杂志 2005年第4期
the College of Physicians and Surgeons, Columbia University
the Cardiovascular Research Foundation (A.J.L., C.P., R.A.C., Y.T., E.A., R.M., M.N., M.F., E.C., M.B.L., G.W.S.)
New York, NY; LeBauer Cardiovascular Research Foundation and Moses Cone Heart and Vascular Center (B.R.B., T.D.S.)
Greensboro, NC; Mid Carolina Cardiology (D.A.C.), Charlotte, NC
Hospital Gregorio Maranon (E.G.), Madrid, Spain
Duke University Medical Center (J.E.T.), Durham, NC
Washington Adventist Hospital (M.T.), Tacoma Park, Md
William Beaumont Hospital (C.L.G.), Royal Oak, Mich.
Abstract
Background— Women with acute myocardial infarction (AMI) undergoing primary angioplasty have higher rates of morbidity and mortality than do men. Whether contemporary interventional treatment strategies have improved outcomes for women compared with men is unknown.
Methods and Results— In the CADILLAC trial, 2082 patients (27% women) with AMI within 12 hours of symptom onset were randomized to balloon angioplasty (PTCA; n=518), PTCA+abciximab (n=528), stenting (n=512), and stenting+abciximab (n=524). As compared with men, women had a lower body surface area; had a greater prevalence of diabetes, hypertension, and hyperlipidemia; experienced significant delays to treatment; and had better baseline and final TIMI grade 3 flows. Unadjusted 1-year event rates were higher for women, including death (7.6% versus 3.0%, P<0.001), ischemic target-vessel revascularization (TVR; 16.7% versus 12.1%, P=0.006), and major adverse cardiac events (MACE; 23.9% versus 15.3%, P<0.001). Female gender was an independent predictor of MACE and bleeding complications, although comorbid risk factors and body surface area but not gender predicted 1-year death. For women, primary stenting resulted in a reduction in 1-year MACE from 28.1% to 19.1% (P=0.01) and in ischemic TVR from 20.4% to 10.8% (P=0.002) compared with PTCA. The addition of abciximab to primary stenting significantly reduced the 30-day ischemic TVR without increasing bleeding or stroke rates.
Conclusions— The higher mortality rate in women compared with men after interventional treatment for AMI may be explained by differences in body size and clinical risk factors, although female gender remains an important independent determinant of overall adverse outcomes. For women in the CADILLAC trial, the addition of abciximab reduced 30-day TVR without increasing bleeding risk, and primary stenting reduced 1-year TVR and MACE rates compared with PTCA.
Key Words: women ; myocardial infarction ; angioplasty ; stents ; coronary disease
Introduction
Women with acute myocardial infarction (AMI) are at increased risk for death compared with men, irrespective of reperfusion modality.1–5 Whether the increased mortality in women is due to the frequent existence of adverse comorbid features or an otherwise-unidentified biological risk factor remains unsettled.5 Primary balloon angioplasty, as compared with thrombolytic therapy, has been shown to improve outcomes for women, but mortality and restenosis rates remain high.5–7 Whether further improvement in outcomes can be achieved in women with contemporary interventional techniques, such as stent implantation and glycoprotein IIb/IIIa inhibitors, is unknown. We therefore analyzed the database from a large, interventional, prospective, multicenter randomized trial of different reperfusion modalities for AMI to assess the contemporary outcomes of women compared with men and to evaluate the optimal interventional approach in women.
Methods
The CADILLAC study design, major inclusion and exclusion criteria, component end-point definitions, and principal results have been reported in detail previously.8 In brief, 2082 patients of any age with AMI within 12 hours of symptom onset who were undergoing primary percutaneous coronary intervention (PCI) were randomized to balloon angioplasty versus stenting with the Multilink stent (Guidant Corp), each with versus without abciximab (Centocor). Important exclusion criteria were cardiogenic shock, history of bleeding diathesis, and recent major surgery or cerebrovascular event. Clinical follow-ups were performed at 1, 6, and 12 months, and angiographic follow-up was scheduled to be performed on a prespecified subgroup of 900 patients at 7 months. The primary end point was major adverse cardiac events (MACE), a composite of death, reinfarction, ischemia-driven target-vessel revascularization (TVR), or disabling stroke. Moderate bleeding was defined by the requirement for blood product transfusion, and severe bleeding, by hemodynamic compromise.
For the purposes of this study, 2 analyses are presented. First, patient demographics and outcomes were compared between men and women. Second, the outcomes of the female population were examined on the basis of randomized treatment allocation to determine the best reperfusion strategy for women specifically.
Statistical Analysis
Categorical variables were compared with the 2 test (for 4-way comparisons) or Fisher exact test (for 2-way comparisons). Continuous variables are presented as medians with interquartile ranges and were compared with the Kruskal-Wallis test. Survival data were estimated by the Kaplan-Meier method and compared by log-rank test. Multivariable analysis of predictors of 1-year death, MACE, and moderate/severe bleeding for all patients and for the female population only were performed with Cox proportional-hazards regression with stepwise selection and entry and exit criteria of P<0.1. The candidate variables entered in the model included age, gender, diabetes mellitus, hypertension, current smoking, history of MI or coronary artery bypass grafting, Killip class II, left anterior descending infarct vessel, triple-vessel disease, treatment with abciximab or stent, time from symptom onset to the first balloon inflation, left ventricular ejection fraction, baseline hematocrit value (as a continuous variable), and body surface area (BSA). A probability value <0.05 was considered significant.
Results
Baseline Characteristics: Comparisons of Men and Women
Comparison of Men and Women: Clinical and Angiographic Outcomes
Outcomes in hospital, at 30 days, and at 1 year are detailed in Tables 3 and 4. Women had more frequent in-hospital complications, including hypotension, congestive heart failure, need for hemodialysis, cardiopulmonary resuscitation, intubation, and death. At 30 days, women had higher rates of MACE, driven by 4-fold greater mortality and disabling stroke rates. Composite MACE rates remained greater in women than in men at 1 year because of higher rates of death and ischemic TVR. Subacute thrombosis rates did not differ between men and women. Binary restenosis rates (30.7% in men versus 33.3% in women, P=0.54) and TVR rates (10.0% in men versus 11.7% in women, P=0.55) were similar for men and women in the angiographic subset. Bleeding complications were more frequent in women at all time points.
After adjusting for differences in baseline clinical characteristics (excluding BSA), female gender was an independent correlate of death at 1 year (odds ratio=1.77; 95% confidence interval [CI], 1.03 to 3.04], P=0.037). After accounting for differences in BSA, gender remained a significant independent predictor of MACE and bleeding complications but not of mortality (Figure 1).
Analysis of Women Only According to Randomized Treatment Allocation
Baseline demographics were similar for women according to treatment allocation (stent±abciximab versus PTCA±abciximab; Table 5). Women randomized to abciximab had better baseline TIMI 3 flow rates compared with no abciximab (30.0% with abciximab versus 20.9% without abciximab, P=0.02), although final TIMI 3 flow rates were similar in all groups. The final minimal luminal diameter was significantly larger in women who underwent stent implantation compared with PTCA.
Primary stenting with or without abciximab resulted in lower rates of ischemic TVR (10.8% versus 20.4%, P=0.002) and MACE (19.1% versus 28.1%, P=0.01) at 1 year compared with PTCA with or without abciximab (Figures 2 and 3). Among women who underwent stent implantation, use of abciximab resulted in lower 30-day rates of ischemic TVR (0.8% versus 5.1%, P=0.03), with no impact on subacute thrombosis (0% versus 1.5%, P=0.16), disabling stroke (0.8% versus 0.8, P=0.97), or major bleeding rates (7.4% versus 6.6%, P=0.74). The early benefit of abciximab in reducing TVR was no longer significant at 1 year (Table 6).
The independent predictors of MACE at 1 year in women included small BSA, left anterior descending coronary artery intervention, baseline hypertension, and randomization to stenting (Figure 1). Randomization to stenting was also an independent predictor of reduced TVR (odds ratio=0.5; 95% CI, 0.3 to 0.83), and the only predictor of moderate to severe bleeding for women was a smaller BSA.
In men, the use of stents conferred similar efficacy as in women. At 1 year, ischemic TVR was 16.4% for PTCA versus 15.8% for PTCA+abciximab versus 9.8% stent versus 6.6% stent+abciximab (P<0.0001), and MACE was 19.8% for PTCA versus 18% for PTCA+abciximab versus 12.4% for stent versus 11.4% for stent+abciximab (P=0.002).
Discussion
Consistent with previous studies,1–7 women with AMI in the CADILLAC study constituted a high-risk population with higher short- and long-term mortality rates relative to men, which may primarily be explained by their older age, smaller BSA, higher frequency of other comorbid risk factors, and more frequent occurrence of periprocedural complications. Female gender per se was not an independent risk factor of death, dispelling the notion of a biological risk associated with female gender. Rather, small BSA (a factor that is not always accounted for in risk analyses)5,9 appears to be a critical factor that confers higher mortality risk in women. The risk associated with a small BSA has been recognized in the setting of elective surgical10 and percutaneous11 revascularization strategies. The mechanism by which small BSA increases mortality is not entirely clear but may relate to more frequent procedural complications of intervention in small vessels, such as dissections12,13 and perforations,14 and greater relative contrast loads and weight-unadjusted pharmacological dosing. Glycoprotein IIb/IIIa inhibitors were weight adjusted in the CADILLAC trial as well as in contemporary PCI.
An important confounding risk factor for women, though not independently predictive of mortality in CADILLAC, is the time delay in achieving definitive therapy. The longer time delays for women from symptom onset to seeking medical attention are well documented and are the focus of current public education programs. The CADILLAC trial, in addition, demonstrated significantly longer delays experienced by women (compared with men) from hospital presentation to interventional treatment, pointing to specific inefficiencies in triage, diagnosis, and catheterization laboratory transfer of women. Mechanisms to minimize delays to definitive treatment (optimally <2 hours) can be expected to have a direct beneficial impact on survival.15 Paradoxically, spontaneous reperfusion (TIMI 3 flow) was more frequent in women, as was the final restoration of normal epicardial flow despite delays in treatment. Consistent with the results of other studies, high (>95%) TIMI 3 flow rates are achieved after PCI irrespective of the timing of intervention,16,17 again suggesting that it is the delay in treatment rather than TIMI 3 flow rates that impart a worse prognosis.15 Thus, longer treatment delays for women may be one important modifiable factor that would improve outcomes.
Procedure-related moderate to severe bleeding rates were 2.5 times higher in women than in men. Older age and randomization to stenting (possibly because of prolonged use of thienopyridines), along with female gender, were independently predictive of major bleeding. BSA and the use of glycoprotein IIb/IIIa inhibitors were not predictive of bleeding. These findings are consistent with other trials that have shown vascular complication rates 2 to 3 times higher after PCI in women than in men, with rates ranging from 4% to 9%.18–22 Weight-adjusted heparin dosing, smaller sheath sizes, earlier sheath removal, and smaller devices have helped to reduce the rates of vascular access and bleeding complications.18,23 Use of the direct antithrombin agent bivalirudin (not used in CADILLAC) has been shown to significantly reduce bleeding complications by up to 40% in the setting of acute coronary syndrome intervention24 and may further reduce the risk of bleeding in women as well, although studies in AMI are required.
Optimizing Outcomes in Women
For women, primary stenting resulted in a reduction in MACE from 28.1% to 19.1%, (P=0.01) and in ischemic TVR from 20.4% to 10.8% (P=0.002) compared with PTCA; stent use independently predicted freedom from TVR and MACE. The addition of abciximab to primary stenting reduced the need for early ischemia-driven revascularization. Evidence favors the use of glycoprotein IIb/IIIa inhibitors in women in the context of elective PCI for stable angina and acute coronary syndromes.25 During rescue PCI after failed thrombolysis, abciximab use increases the risk of bleeding and vascular complications for women specifically and should be avoided in this context.26,27 The benefit of abciximab in women undergoing primary PCI for AMI has not been examined previously. In CADILLAC, the addition of abciximab significantly reduced ischemic TVR at 30 days after both primary balloon angioplasty and stenting, without an increased risk of major bleeding or stroke. This benefit was tempered by a nonstatistically significant higher absolute mortality rate in women treated with stenting+abciximab. This finding was most likely due to chance, given an opposite trend noted in women randomized to PTCA+abciximab versus PTCA alone.
Limitations
This analysis, though prespecified, must be considered hypothesis generating and is only applicable to the population studied. Although CADILLAC is the largest, primary PCI population study to date for evaluating the outcomes of AMI in women, the numbers studied are still insufficient to determine whether stenting or glycoprotein IIb/IIIa inhibitors favorably or unfavorably affect mortality in women. Moreover, abciximab was administered minutes before PCI in CADILLAC; whether earlier use in women (eg, in the ambulance or emergency department) might prove beneficial (as suggested in the ADMIRAL study in men and women)26,27 deserves further study.
Conclusions
In the CADILLAC trial, women had higher mortality rates compared with men after interventional treatment for AMI. This may be related to their generally smaller BSA and higher prevalence of comorbidities, which predicted death, MACE and bleeding complications at 1 year. Primary stenting reduced clinical and angiographic restenosis and significantly reduced MACE in women. Adjunctive abciximab use in primary stenting for women reduced 30-day ischemia-driven revascularization, without increasing major bleeding or stroke rates. Efforts to reduce the time delays to reperfusion experienced by women offer the potential to further improve their prognosis.
References
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Zijlstra F, Hoorntje JC, de Boer MJ, Reiffers S, Miedema K, Ottervanger JP, van’T Hof AW, Suryapranata H. Long-term benefit of primary angioplasty as compared with thrombolytic therapy for acute myocardial infarction. N Engl J Med. 1999; 341: 1413–1419.
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Peterson ED, Lansky AJ, Kramer J, Anstrom K, Lanzilotta MJ. Effect of gender on the outcomes of contemporary percutaneous coronary intervention. Am J Cardiol. 2001; 88: 359–364.
McEniery PT, Hollman J, Knezinek V, Dorosti K, Franco I, Simpfendorfer C, Whitlow P. Comparative safety and efficacy of percutaneous transluminal coronary angioplasty in men and in women. Cathet Cardiovasc Diagn. 1987; 13: 364–371.
Ilia R, Bigham H, Brennan J, Cabin H, Cleman M, Remetz M. Predictors of coronary dissection following percutaneous transluminal coronary balloon angioplasty. Cardiology. 1994; 85: 229–234.
Ellis SG, Ajluni S, Arnold AZ, Popma JJ, Bittl JA, Eigler NL, Cowley MJ, Raymond RE, Safian RD, Whitlow PL. Increased coronary perforation in the new device era: incidence, classification, management, and outcome. Circulation. 1994; 90: 2725–2730.
Brodie BR, Stuckey TD, Wall TC, Kissling G, Hansen CJ, Muncy DB, Weintraub RA, Kelly TA. Importance of time to reperfusion for 30 day and late survival and recovery of left ventricular function after primary angioplasty for acute myocardial infarction. J Am Coll Cardiol. 1998; 32: 1312–1319.
Berger PB, Ellis SG, Holmes DR, Granger CB, Criger DA, Betriu A, Topol EJ, Califf RM. Relationship between delay in performing direct coronary angioplasty and early clinical outcomes in patients with acute myocardial infarction: results from the GUSTO-IIb trial. Circulation. 1999; 100: 14–20.
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Taddei CF, Weintraub WS, Douglas JS Jr, Ghazzal Z, Mahoney E, Thompson T, King S 3rd. Influence of age on outcome after percutaneous transluminal coronary angioplasty. Am J Cardiol. 1999; 84: 245–251.
Robertson T, Kennard ED, Mehta S, Popma JJ, Carrozza JP Jr, King SB 3rd, Holmes DR, Cowley MJ, Hornung CA, Kent KM, Roubin GS, Litvack F, Moses JW, Safian R, Desvigne-Nickens P, Detre KM. Influence of gender on in-hospital clinical and angiographic outcomes and on one-year follow-up in the New Approaches to Coronary Intervention (NACI) registry. Am J Cardiol. 1997; 80: 26K–39K.
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Lincoff AM, Bittl JA, Harrington RA, Feit F, Kleiman NS, Jackman JD, Sarembock IJ, Cohen DJ, Spriggs D, Ebrahimi R, Keren G, Carr J, Cohen EA, Betriu A, Desmet W, Kereiakes DJ, Rutsch W, Wilcox RG, de Feyter PJ, Vaharian A, Topol EJ; REPLACE-2 Investigators. Bivalirudin and provisional glycoprotein IIb/IIIa blockade compared with heparin and planned glycoprotein IIb/IIIa blockade during percutaneous coronary intervention: REPLACE-2 randomized trial. JAMA. 2003; 289: 853–863.
Cho L, Topol EJ, Balog C, Foody JM, Booth JE, Cabot C, Kleiman NS, Tcheng JE, Califf R, Lincoff AM. Clinical benefit of glycoprotein IIb/IIIa blockade with abciximab is independent of gender: pooled analysis from EPIC, EPILOG, and EPISTENT trials. J Am Coll Cardiol. 2000; 36: 381–386.
Montalescot G, Barragan P, Wittenberg O, Ecollan P, Elhadad S, Villain P, Boulenc JM, Morice MC, Maillard L, Pansieri M, Choussat R, Pinton P. Platelet glycoprotein IIb/IIIa inhibitor with coronary stenting for acute myocardial infarction. N Engl J Med. 2001; 344: 1895–1903.
Cantor WJ, Kaplan AL, Velianou JL, Sketch MH Jr, Barsness GW, Berger PB, Ohman EM. Effectiveness and safety of abciximab after failed thrombolytic therapy. Am J Cardiol. 2001; 87: 439–442, A434.(Alexandra J. Lansky, MD; )
the Cardiovascular Research Foundation (A.J.L., C.P., R.A.C., Y.T., E.A., R.M., M.N., M.F., E.C., M.B.L., G.W.S.)
New York, NY; LeBauer Cardiovascular Research Foundation and Moses Cone Heart and Vascular Center (B.R.B., T.D.S.)
Greensboro, NC; Mid Carolina Cardiology (D.A.C.), Charlotte, NC
Hospital Gregorio Maranon (E.G.), Madrid, Spain
Duke University Medical Center (J.E.T.), Durham, NC
Washington Adventist Hospital (M.T.), Tacoma Park, Md
William Beaumont Hospital (C.L.G.), Royal Oak, Mich.
Abstract
Background— Women with acute myocardial infarction (AMI) undergoing primary angioplasty have higher rates of morbidity and mortality than do men. Whether contemporary interventional treatment strategies have improved outcomes for women compared with men is unknown.
Methods and Results— In the CADILLAC trial, 2082 patients (27% women) with AMI within 12 hours of symptom onset were randomized to balloon angioplasty (PTCA; n=518), PTCA+abciximab (n=528), stenting (n=512), and stenting+abciximab (n=524). As compared with men, women had a lower body surface area; had a greater prevalence of diabetes, hypertension, and hyperlipidemia; experienced significant delays to treatment; and had better baseline and final TIMI grade 3 flows. Unadjusted 1-year event rates were higher for women, including death (7.6% versus 3.0%, P<0.001), ischemic target-vessel revascularization (TVR; 16.7% versus 12.1%, P=0.006), and major adverse cardiac events (MACE; 23.9% versus 15.3%, P<0.001). Female gender was an independent predictor of MACE and bleeding complications, although comorbid risk factors and body surface area but not gender predicted 1-year death. For women, primary stenting resulted in a reduction in 1-year MACE from 28.1% to 19.1% (P=0.01) and in ischemic TVR from 20.4% to 10.8% (P=0.002) compared with PTCA. The addition of abciximab to primary stenting significantly reduced the 30-day ischemic TVR without increasing bleeding or stroke rates.
Conclusions— The higher mortality rate in women compared with men after interventional treatment for AMI may be explained by differences in body size and clinical risk factors, although female gender remains an important independent determinant of overall adverse outcomes. For women in the CADILLAC trial, the addition of abciximab reduced 30-day TVR without increasing bleeding risk, and primary stenting reduced 1-year TVR and MACE rates compared with PTCA.
Key Words: women ; myocardial infarction ; angioplasty ; stents ; coronary disease
Introduction
Women with acute myocardial infarction (AMI) are at increased risk for death compared with men, irrespective of reperfusion modality.1–5 Whether the increased mortality in women is due to the frequent existence of adverse comorbid features or an otherwise-unidentified biological risk factor remains unsettled.5 Primary balloon angioplasty, as compared with thrombolytic therapy, has been shown to improve outcomes for women, but mortality and restenosis rates remain high.5–7 Whether further improvement in outcomes can be achieved in women with contemporary interventional techniques, such as stent implantation and glycoprotein IIb/IIIa inhibitors, is unknown. We therefore analyzed the database from a large, interventional, prospective, multicenter randomized trial of different reperfusion modalities for AMI to assess the contemporary outcomes of women compared with men and to evaluate the optimal interventional approach in women.
Methods
The CADILLAC study design, major inclusion and exclusion criteria, component end-point definitions, and principal results have been reported in detail previously.8 In brief, 2082 patients of any age with AMI within 12 hours of symptom onset who were undergoing primary percutaneous coronary intervention (PCI) were randomized to balloon angioplasty versus stenting with the Multilink stent (Guidant Corp), each with versus without abciximab (Centocor). Important exclusion criteria were cardiogenic shock, history of bleeding diathesis, and recent major surgery or cerebrovascular event. Clinical follow-ups were performed at 1, 6, and 12 months, and angiographic follow-up was scheduled to be performed on a prespecified subgroup of 900 patients at 7 months. The primary end point was major adverse cardiac events (MACE), a composite of death, reinfarction, ischemia-driven target-vessel revascularization (TVR), or disabling stroke. Moderate bleeding was defined by the requirement for blood product transfusion, and severe bleeding, by hemodynamic compromise.
For the purposes of this study, 2 analyses are presented. First, patient demographics and outcomes were compared between men and women. Second, the outcomes of the female population were examined on the basis of randomized treatment allocation to determine the best reperfusion strategy for women specifically.
Statistical Analysis
Categorical variables were compared with the 2 test (for 4-way comparisons) or Fisher exact test (for 2-way comparisons). Continuous variables are presented as medians with interquartile ranges and were compared with the Kruskal-Wallis test. Survival data were estimated by the Kaplan-Meier method and compared by log-rank test. Multivariable analysis of predictors of 1-year death, MACE, and moderate/severe bleeding for all patients and for the female population only were performed with Cox proportional-hazards regression with stepwise selection and entry and exit criteria of P<0.1. The candidate variables entered in the model included age, gender, diabetes mellitus, hypertension, current smoking, history of MI or coronary artery bypass grafting, Killip class II, left anterior descending infarct vessel, triple-vessel disease, treatment with abciximab or stent, time from symptom onset to the first balloon inflation, left ventricular ejection fraction, baseline hematocrit value (as a continuous variable), and body surface area (BSA). A probability value <0.05 was considered significant.
Results
Baseline Characteristics: Comparisons of Men and Women
Comparison of Men and Women: Clinical and Angiographic Outcomes
Outcomes in hospital, at 30 days, and at 1 year are detailed in Tables 3 and 4. Women had more frequent in-hospital complications, including hypotension, congestive heart failure, need for hemodialysis, cardiopulmonary resuscitation, intubation, and death. At 30 days, women had higher rates of MACE, driven by 4-fold greater mortality and disabling stroke rates. Composite MACE rates remained greater in women than in men at 1 year because of higher rates of death and ischemic TVR. Subacute thrombosis rates did not differ between men and women. Binary restenosis rates (30.7% in men versus 33.3% in women, P=0.54) and TVR rates (10.0% in men versus 11.7% in women, P=0.55) were similar for men and women in the angiographic subset. Bleeding complications were more frequent in women at all time points.
After adjusting for differences in baseline clinical characteristics (excluding BSA), female gender was an independent correlate of death at 1 year (odds ratio=1.77; 95% confidence interval [CI], 1.03 to 3.04], P=0.037). After accounting for differences in BSA, gender remained a significant independent predictor of MACE and bleeding complications but not of mortality (Figure 1).
Analysis of Women Only According to Randomized Treatment Allocation
Baseline demographics were similar for women according to treatment allocation (stent±abciximab versus PTCA±abciximab; Table 5). Women randomized to abciximab had better baseline TIMI 3 flow rates compared with no abciximab (30.0% with abciximab versus 20.9% without abciximab, P=0.02), although final TIMI 3 flow rates were similar in all groups. The final minimal luminal diameter was significantly larger in women who underwent stent implantation compared with PTCA.
Primary stenting with or without abciximab resulted in lower rates of ischemic TVR (10.8% versus 20.4%, P=0.002) and MACE (19.1% versus 28.1%, P=0.01) at 1 year compared with PTCA with or without abciximab (Figures 2 and 3). Among women who underwent stent implantation, use of abciximab resulted in lower 30-day rates of ischemic TVR (0.8% versus 5.1%, P=0.03), with no impact on subacute thrombosis (0% versus 1.5%, P=0.16), disabling stroke (0.8% versus 0.8, P=0.97), or major bleeding rates (7.4% versus 6.6%, P=0.74). The early benefit of abciximab in reducing TVR was no longer significant at 1 year (Table 6).
The independent predictors of MACE at 1 year in women included small BSA, left anterior descending coronary artery intervention, baseline hypertension, and randomization to stenting (Figure 1). Randomization to stenting was also an independent predictor of reduced TVR (odds ratio=0.5; 95% CI, 0.3 to 0.83), and the only predictor of moderate to severe bleeding for women was a smaller BSA.
In men, the use of stents conferred similar efficacy as in women. At 1 year, ischemic TVR was 16.4% for PTCA versus 15.8% for PTCA+abciximab versus 9.8% stent versus 6.6% stent+abciximab (P<0.0001), and MACE was 19.8% for PTCA versus 18% for PTCA+abciximab versus 12.4% for stent versus 11.4% for stent+abciximab (P=0.002).
Discussion
Consistent with previous studies,1–7 women with AMI in the CADILLAC study constituted a high-risk population with higher short- and long-term mortality rates relative to men, which may primarily be explained by their older age, smaller BSA, higher frequency of other comorbid risk factors, and more frequent occurrence of periprocedural complications. Female gender per se was not an independent risk factor of death, dispelling the notion of a biological risk associated with female gender. Rather, small BSA (a factor that is not always accounted for in risk analyses)5,9 appears to be a critical factor that confers higher mortality risk in women. The risk associated with a small BSA has been recognized in the setting of elective surgical10 and percutaneous11 revascularization strategies. The mechanism by which small BSA increases mortality is not entirely clear but may relate to more frequent procedural complications of intervention in small vessels, such as dissections12,13 and perforations,14 and greater relative contrast loads and weight-unadjusted pharmacological dosing. Glycoprotein IIb/IIIa inhibitors were weight adjusted in the CADILLAC trial as well as in contemporary PCI.
An important confounding risk factor for women, though not independently predictive of mortality in CADILLAC, is the time delay in achieving definitive therapy. The longer time delays for women from symptom onset to seeking medical attention are well documented and are the focus of current public education programs. The CADILLAC trial, in addition, demonstrated significantly longer delays experienced by women (compared with men) from hospital presentation to interventional treatment, pointing to specific inefficiencies in triage, diagnosis, and catheterization laboratory transfer of women. Mechanisms to minimize delays to definitive treatment (optimally <2 hours) can be expected to have a direct beneficial impact on survival.15 Paradoxically, spontaneous reperfusion (TIMI 3 flow) was more frequent in women, as was the final restoration of normal epicardial flow despite delays in treatment. Consistent with the results of other studies, high (>95%) TIMI 3 flow rates are achieved after PCI irrespective of the timing of intervention,16,17 again suggesting that it is the delay in treatment rather than TIMI 3 flow rates that impart a worse prognosis.15 Thus, longer treatment delays for women may be one important modifiable factor that would improve outcomes.
Procedure-related moderate to severe bleeding rates were 2.5 times higher in women than in men. Older age and randomization to stenting (possibly because of prolonged use of thienopyridines), along with female gender, were independently predictive of major bleeding. BSA and the use of glycoprotein IIb/IIIa inhibitors were not predictive of bleeding. These findings are consistent with other trials that have shown vascular complication rates 2 to 3 times higher after PCI in women than in men, with rates ranging from 4% to 9%.18–22 Weight-adjusted heparin dosing, smaller sheath sizes, earlier sheath removal, and smaller devices have helped to reduce the rates of vascular access and bleeding complications.18,23 Use of the direct antithrombin agent bivalirudin (not used in CADILLAC) has been shown to significantly reduce bleeding complications by up to 40% in the setting of acute coronary syndrome intervention24 and may further reduce the risk of bleeding in women as well, although studies in AMI are required.
Optimizing Outcomes in Women
For women, primary stenting resulted in a reduction in MACE from 28.1% to 19.1%, (P=0.01) and in ischemic TVR from 20.4% to 10.8% (P=0.002) compared with PTCA; stent use independently predicted freedom from TVR and MACE. The addition of abciximab to primary stenting reduced the need for early ischemia-driven revascularization. Evidence favors the use of glycoprotein IIb/IIIa inhibitors in women in the context of elective PCI for stable angina and acute coronary syndromes.25 During rescue PCI after failed thrombolysis, abciximab use increases the risk of bleeding and vascular complications for women specifically and should be avoided in this context.26,27 The benefit of abciximab in women undergoing primary PCI for AMI has not been examined previously. In CADILLAC, the addition of abciximab significantly reduced ischemic TVR at 30 days after both primary balloon angioplasty and stenting, without an increased risk of major bleeding or stroke. This benefit was tempered by a nonstatistically significant higher absolute mortality rate in women treated with stenting+abciximab. This finding was most likely due to chance, given an opposite trend noted in women randomized to PTCA+abciximab versus PTCA alone.
Limitations
This analysis, though prespecified, must be considered hypothesis generating and is only applicable to the population studied. Although CADILLAC is the largest, primary PCI population study to date for evaluating the outcomes of AMI in women, the numbers studied are still insufficient to determine whether stenting or glycoprotein IIb/IIIa inhibitors favorably or unfavorably affect mortality in women. Moreover, abciximab was administered minutes before PCI in CADILLAC; whether earlier use in women (eg, in the ambulance or emergency department) might prove beneficial (as suggested in the ADMIRAL study in men and women)26,27 deserves further study.
Conclusions
In the CADILLAC trial, women had higher mortality rates compared with men after interventional treatment for AMI. This may be related to their generally smaller BSA and higher prevalence of comorbidities, which predicted death, MACE and bleeding complications at 1 year. Primary stenting reduced clinical and angiographic restenosis and significantly reduced MACE in women. Adjunctive abciximab use in primary stenting for women reduced 30-day ischemia-driven revascularization, without increasing major bleeding or stroke rates. Efforts to reduce the time delays to reperfusion experienced by women offer the potential to further improve their prognosis.
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