Abstract
Background
The introduction of drug‐eluting stents (DES) dramatically changed the practice of percutaneous coronary intervention (PCI) in the 2000s. Little is known about trends in in‐hospital outcome after PCI in the DES era.
Hypothesis
The in‐hospital outcomes after PCI might be continuously improved over time.
Methods
We analyzed in‐hospital outcomes of 21 667 patients who underwent PCI at Fu Wai Hospital in the past 5 years. The patients were divided into 5 groups according to the time of their intervention: group 1 (June 2004 to May 2005), group 2 (June 2005 to May 2006), group 3 (June 2006 to May 2007), group 4 (June 2007 to May 2008), and group 5 (June 2008 to May 2009).
Results
Procedural success rates for the 5 groups were 93.6%, 95%, 94.4%, 94.2%, and 94.3%, respectively (P = 0.39). Significant reduction in in‐hospital major adverse cardiac events (3.1%, 3.4%, 2.8%, 1.6%, and 1.0%, P < 0.001) and need for target‐vessel revascularization (2.0%, 2.2%, 1.5%, 0.4%, and 0.2%, P < 0.001) was noted over time, which was associated with a significant increase in use of DES (from 56.6% to 97.0%, P < 0.001). On multivariate analysis, use of DES, dissection during procedure, left main lesion, prior myocardial infarction, and age ≥ 65 years were independent predictors of major adverse cardiovascular events.
Conclusions
There were substantial reductions in in‐hospital major adverse cardiac events and target‐vessel revascularization over the past 5 years. This reduction was associated with the concurrent increased use of DES. Copyright © 2010 Wiley Periodicals, Inc.
This work was performed at the Cardiovascular Institute and Fu Wai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
The authors have no funding, financial relationships, or conflicts of interest to disclose.
Introduction
Drug‐eluting stents (DES) have revolutionized the field of interventional cardiology and have largely demonstrated their superiority to bare‐metal stents with respect to in‐stent restenosis.1, 2, 3 Furthermore, recent evidence has shown that DES did not result in excess mortality compared with bare‐metal stents.4, 5, 6, 7 There have been numerous technical and pharmacological advances in the field of percutaneous coronary intervention (PCI) since DES inception. Comparison between outcomes to establish temporal trends is difficult because of the variable inclusion criteria, definitions of procedural success, and clinical endpoints. Previous studies that analyzed the temporal trends of coronary angioplasty do not reflect current practice patterns. Thus, the aim of our study was to examine the trends in in‐hospital outcomes after PCI during the last 5 years and to examine the impact of DES.
Methods
Study Design and Patient Population
Since 2004, 21 667 patients who underwent PCI at Fu Wai Hospital in Beijing, China, have been followed in a registry. The registry includes demographic, clinical, angiographic, and procedural data. We conducted a retrospective, time‐series analysis of in‐hospital outcomes of patients who underwent PCI between June 1, 2004, and May 31, 2009. These patients were divided into 5 groups according to the time of their intervention: group 1, from June 2004 to May 2005 (n = 3210); group 2, from June 2005 to May 2006 (n = 3398); group 3, from June 2006 to May 2007 (n = 4219); group 4, from June 2007 to May 2008 (n = 5057); and group 5, from June 2008 to May 2009 (n = 5783).
Definitions of Endpoints
The outcomes of interest in the study were major adverse cardiovascular events (MACE), defined as 1 or more of the following: (1) in‐hospital death, (2) nonfatal myocardial infarction (MI) during the hospitalization, and (3) urgent or emergent target‐vessel revascularization (TVR) during the hospitalization. MI was diagnosed according to standard criteria (rise in creatine kinase [CK] level to more than twice the upper limit of normal, with increased CK‐MB and new Q waves). TVR was defined as any attempted percutaneous or surgical revascularization of the target vessel after the initial procedure. Procedural success was defined as a reduction of residual luminal diameter stenosis to < 50% without in‐hospital death, nonfatal MI, or need for emergency TVR. Vascular complications included major bleeding (requiring prolonged hospitalization, surgical intervention, or blood transfusion), pseudoaneurysms (requiring surgical or percutaneous intervention), and arteriovenous fistulas.
Statistical Analysis
Continuous variables were expressed as mean ± SD and categorical variables were expressed as percentages. Tests for trends across time periods were made using linear contrasts of means in a one‐way analysis of variance (ANOVA) model for numerical data, the Cochran‐Armitage trend test for categorical data. Univariate logistic regression analysis and multivariate analysis were performed to identify independent predictors of MACE using the following variables: age ≥ 65 years, male gender, hypertension, hyperlipidemia, diabetes mellitus, prior PCI, prior coronary artery bypass graft (CABG), prior MI, acute MI, use of DES, American College of Cardiology/American Heart Association type C lesion, left main lesion, ostial lesion, bifurcation lesion, bypass graft lesions, chronic total occlusion > 3 months, total stent length, direct stenting, postdilatation of stenting, and dissection during procedure. Multiple‐variable predictors were chosen by a stepwise procedure with an entry criterion of 0.10 and with a stay criterion 0.05. P values of < 0.05 were considered statistically significant. All analyses were performed with SAS 9.1 software (SAS Institute, Inc., Cary, NC).
Results
Baseline Clinical Characteristics
Baseline clinical characteristics of the 5 groups are shown in Table 1. Between June 1, 2004, and May 31, 2009, a total of 21 667 PCIs were performed in Fu Wai Hospital, which involved the treatment of 32 920 lesions. The mean patient age and proportion of female gender, prior PCI, prior CABG, and indications for procedures remained stable. However, the prevalence of hypertension (from 46.1% to 56.6%, P < 0.001) and diabetes mellitus (from 18.3% to 21.8%, P < 0.001) significantly increased, as did the proportion of prior MI (from 26.9% to 46.2%, P < 0.001) and current smoker (from 29.2% to 38.2%, P < 0.001).
Table 1.
Baseline Clinical Characteristics of Patients
| Variable | Group 1 (n=3210) | Group 2 (n=3398) | Group 3 (n=4219) | Group 4 (n=5057) | Group 5 (n=5783) | P Valuea |
|---|---|---|---|---|---|---|
| F, n (%) | 629 (19.6) | 631 (18.6) | 863 (20.5) | 1089 (21.5) | 1102 (19.1) | 0.28 |
| Age, y | 57.9±10.8 | 57.9±10.6 | 58.2±10.8 | 57.9±10.7 | 57.4±10.9 | 0.28 |
| HT, n (%) | 1480 (46.1) | 1692 (49.8) | 2382 (56.5) | 2928 (57.9) | 3273 (56.6) | <0.001 |
| DM, n (%) | 587 (18.3) | 676 (19.9) | 903 (21.4) | 1128 (22.3) | 1261 (21.8) | <0.001 |
| HL, n (%) | 990 (30.8) | 1248 (36.7) | 1484 (35.2) | 1534 (30.3) | 1989 (34.4) | 0.46 |
| Prior PCI, n (%) | 634 (19.8) | 694 (20.4) | 852 (20.2) | 989 (19.6) | 1096 (20.0) | 0.07 |
| Prior CABG, n (%) | 75 (2.4) | 62 (1.8) | 124 (2.9) | 142 (2.8) | 136 (2.4) | 0.16 |
| Prior MI, n (%) | 864 (26.9) | 1159 (34.1) | 1719 (40.7) | 2164 (42.8) | 2672 (46.2) | <0.001 |
| Current smoker, n (%) | 937 (29.2) | 1081 (31.8) | 1453 (34.4) | 1901 (37.6) | 2209 (38.2) | <0.001 |
| Indication | ||||||
| Stable AP, n (%) | 652 (20.3) | 666 (19.6) | 835 (19.8) | 1022 (20.2) | 1139 (19.7) | 0.38 |
| Unstable AP, n (%) | 1599 (49.8) | 1719 (50.6) | 2126 (50.4) | 2518 (49.8) | 2863 (49.5) | 0.24 |
| Acute MI, n (%) | 959 (29.9) | 1013 (30.4) | 1258 (29.8) | 1517 (30.0) | 1781 (30.8) | 0.14 |
Abbreviations: AP, angina pectoris; CABG, coronary artery bypass grafting; DM, diabetes mellitus; F, female; HL, hyperlipidemia; HT, hypertension; MI, myocardial infarction; n, number of patients; PCI, percutaneous coronary intervention.
Pvalues are for trends across time periods
Angiographic and Procedural Characteristics
Table 2 summarizes the angiographic and procedural characteristics. There was no significant difference in the distribution of the target vessel treated among the groups, except that the proportion of left main progressively increased (from 2.7% to 3.8%, P < 0.001). The frequency of complex lesions including type C lesions and ostial lesions, as well as chronic total occlusion > 3 months, also increased during the period.
Table 2.
Angiographic Lesion Characteristics and Procedural Details of the Study Groups
| Variable | Group 1 | Group 2 | Group 3 | Group 4 | Group 5 | P Valuea |
|---|---|---|---|---|---|---|
| Target coronary artery, n/total (%) | ||||||
| Left anterior descending | 2166/5110 (42.4) | 2364/5427 (43.6) | 2809/6547 (42.9) | 3245/7633 (42.5) | 3427/8203 (41.8) | 0.09 |
| Left circumflex | 1214/5110 (23.7) | 1177/5427 (21.7) | 1450/6547 (22.2) | 1692/7633 (22.2) | 1946/8203 (23.7) | 0.25 |
| Right coronary | 1575/5110 (30.8) | 1698/5427 (31.3) | 2039/6547 (31.1) | 2391/7633 (31.3) | 2489/8203 (30.3) | 0.25 |
| Left main | 137/5110 (2.7) | 167/5427 (3.1) | 215/6547 (3.3) | 269/7633 (3.5) | 317/8203 (3.8) | <0.001 |
| Bypass graft | 18/5110 (0.4) | 21/5427 (0.4) | 34/6547 (0.5) | 36/7633 (0.5) | 24/8203 (0.4) | 0.41 |
| ACC/AHA type C | 1967/5110 (38.5) | 2404/5427 (44.3) | 3528/6547 (53.9) | 3990/7633 (52.3) | 4330/8203 (52.8) | <0.001 |
| Bifurcated lesion | 1672/5110 (32.7) | 2005/5427 (36.9) | 2286/6547 (34.9) | 2650/7633 (34.7) | 2882/8203 (35.1) | 0.13 |
| Ostial lesion | 723/5110 (14.1) | 749/5427 (13.8) | 824/6547 (12.6) | 1042/7633 (13.7) | 1275/8203 (15.5) | 0.006 |
| Chronic total occlusion > mo | 355/5110 (6.9) | 400/5427 (7.4) | 553/6547 (8.1) | 695/7633 (9.1) | 748/8203 (9.1) | <0.001 |
| In‐stent restenosis lesion | 228/5110 (4.5) | 170/5427 (3.1) | 150/6547 (2.3) | 199/5110 (2.6) | 174/8203 (2.1) | <0.001 |
| During procedure | ||||||
| No. of lesions per patient | 1.6±0.8 | 1.6±0.8 | 1.6±0.8 | 1.5±0.7 | 1.5±0.7 | 0.12 |
| No. of stents per patient | 1.6±0.8 | 1.8±1.1 | 1.8±1.2 | 1.8±1.1 | 1.7±1.1 | 0.25 |
| Use of DES, n/total (%) | 3106/5507 (56.4) | 5091/6047(84.2) | 7661/7967 (96.2) | 8669/9056 (95.7) | 9376/9669 (97.0) | <0.001 |
| Total stent length, mm | 25.0±12.1 | 28.6±14.5 | 29.2±16.0 | 29.4±16.5 | 30.6±16.1 | <0.001 |
| Direct stenting, n/total (%) | 1318/5507 (17.0) | 1353/6047 (22.4) | 1436/7967 (18.0) | 1467/9056 (16.2) | 1059/9669 (11.0) | <0.001 |
| Postdilatation of stenting, n/total (%) | 973/5507 (17.7) | 1189/6047 (19.6) | 1676/7967 (21.0) | 1924/9056 (21.2) | 2323/9669 (24.0) | <0.001 |
| Transradial approach, n/total (%) | 2855/5110 (56.0) | 3396/5427 (62.6) | 5121/6547 (78.2) | 6113/7633 (80.3) | 7252/8203 (88.4) | <0.001 |
| Dissection during procedure, n/total (%) | 15/3210 (0.5) | 14/3398 (0.4) | 14/4219 (0.3) | 22/5057 (0.4) | 28/5783 (0.5) | 0.36 |
| Vascular complications, n/total (%) | 17/3210 (0.5) | 15/3398 (0.4) | 18/4219 (0.4) | 13/5057 (0.3) | 8/5783 (0.1) | <0.001 |
| Procedure complications,b n/total (%) | 46/3210 (1.4) | 63/3398 (1.9) | 45/4219 (1.1) | 84/5057 (1.7) | 67/5783 (1.2) | 0.21 |
| Procedure success, n/total (%) | 3006/3210 (93.6) | 3133/3298 (95.0) | 3983/4219 (94.4) | 4764/5057 (94.2) | 5453/5783 (94.3) | 0.39 |
Abbreviations: ACC, American College of Cardiology; AHA, American Heart Association; DES, drug‐eluting stent.
Pvalues are for trends across time periods.
Includes systemic and peripheral complications such as MI, death, arrhythmia, coronary perforation, dissection, and other vascular complications
From 2004 to 2008, there was a steep increase in the application of DES, from 56.4% to 97.0%. The procedural characteristics, such as the number of lesions per patient and the number of stents per patient, were similar among the 5 groups. The total stent length and the rate of stent postdilatation increased steadily, but the frequency of direct stenting was diminished. There was no significant difference in the procedural success rates among the groups (from 93.6% to 94.3%, P = 0.39) or the rates of procedure complications (from 1.4% to 1.2%, P = 0.12). The rate of transradial approach increased markedly over time, from 56.0% to 88.4% (P < 0.001), whereas the incidence of vascular complications continuously decreased (from 0.5% to 0.1%, P < 0.001). In a further analysis, we divided all patients into 2 cohorts according to access site, the transradial approach cohort and the transfemoral approach cohort. Vascular complications were less frequent in the transradial approach cohort than in the transfemoral approach cohort (0.2% vs 1.0%, P < 0.001), although the incidence of in‐hospital MACE was similar in the 2 cohorts.
Trends in In‐Hospital Outcomes
The in‐hospital outcomes are displayed in Table 3. In‐hospital MACE dramatically decreased over time (from 3.1% to 1.0%, P < 0.001), as did acute MI (from 1.0% to 0.5%, P < 0.001). There was a trend toward a reduction in mortality among the 5 groups (0.4% to 0.2%, P = 0.05). The incidence of TVR was 2.0% for group 1, 2.2% for group 2, 1.5% for group 3, 0.4% for group 4, and 0.2% for group 5. This translated into a 90% reduction in the need for TVR over time, with a major decrease between groups 2, 3, and 4, which was driven mainly by the reduction in PCI (from 1.9% to 0.2%, P < 0.001).
Table 3.
In‐Hospital Outcomes in the Study Groups
| Variable | Group 1 (n=3210) | Group 2 (n=3398) | Group 3 (n=4219) | Group 4 (n=5057) | Group 5 (n=5783) | P Valuea |
|---|---|---|---|---|---|---|
| MACE, n (%) | 99 (3.1) | 122 (3.4) | 119 (2.8) | 82 (1.6) | 50 (1.0) | <0.001 |
| Death, n (%) | 13 (0.4) | 9 (0.3) | 18 (0.4) | 16 (0.3) | 11 (0.2) | 0.06 |
| Acute MI, n (%) | 32 (1.0) | 57 (1.2) | 56 (1.3) | 52 (1.0) | 28 (0.5) | <0.001 |
| TVR, n (%) | 65 (2.0) | 75 (2.2) | 64 (1.5) | 22 (0.4) | 13 (0.2) | <0.001 |
| CABG, n (%) | 4 (0.1) | 5 (0.1) | 1 (0.0) | 3 (0.1) | 1 (0.0) | 0.012 |
| PCI, n (%) | 61 (1.9) | 70 (2.1) | 63 (1.5) | 19 (0.3) | 12 (0.2) | <0.001 |
Abbreviations: CABG, coronary artery bypass grafting; MACE, major adverse cardiovascular event; MI, myocardial infarction; PCI, percutaneous coronary intervention; TVR, target‐vessel revascularization.
P values are for trends across time periods
Predictors of In‐Hospital MACE
The results of the logistic regression analysis are shown in Table 4. A simple logistic regression analysis revealed that use of DES, ostial lesion, prior PCI, hyperlipidemia, dissection during procedure, prior MI, left main lesion, age ≥ 65 years, hypertension, and total stent length correlated with in‐hospital MACE. Furthermore, in the multivariable logistic analysis, the independent predictors of in‐hospital MACE were use of DES, dissection during procedure, prior MI, left main lesion, and age ≥ 65 years, whereas use of DES was the only protective factor to decrease in‐hospital MACE (hazard ratio [HR]: 0.39, 95% confidence interval [CI]: 0.31–0.49, P < 0.001). The final multivariate model fit the data well (Hosmer‐Lemeshow test P = 0.42, χ2 = 8.15) and had a good predictive accuracy (C statistic = 0.721).
Table 4.
Univariate and Multivariate Analysis of Predicators for In‐Hospital MACE
| Variable | HR | 95%CI | P Value |
|---|---|---|---|
| Univariate analysis | |||
| Use of DES | 0.40 | 0.32– 0.50 | <0.001 |
| Ostial lesion | 0.73 | 0.51– 0.98 | 0.04 |
| Prior PCI | 0.75 | 0.57– 0.99 | 0.04 |
| HL | 0.83 | 0.66– 1.00 | 0.05 |
| Dissection during procedure | 4.96 | 3.34– 7.37 | <0.001 |
| Prior MI | 2.52 | 2.04– 3.10 | <0.001 |
| Left main lesion | 2.28 | 1.46– 3.55 | <0.001 |
| Age ≥65 y | 1.83 | 1.48– 2.26 | <0.001 |
| HT | 1.28 | 1.04– 1.58 | 0.02 |
| Total stent length | 1.01 | 1.00– 1.02 | 0.04 |
| Multivariate analysis | |||
| Use of DES | 0.39 | 0.31– 0.49 | <0.001 |
| Dissection during procedure | 5.05 | 3.41– 7.47 | <0.001 |
| Prior MI | 2.57 | 2.09– 3.16 | <0.001 |
| Left main lesion | 2.42 | 1.56– 3.74 | <0.001 |
| Age ≥65 y | 1.83 | 1.49– 2.24 | <0.001 |
Abbreviations: CI, confidence interval; DES, drug‐eluting stent; HL, hyperlipidemia; HR, hazard ratio; HT, hypertension; MACE, major adverse cardiovascular event; MI, myocardial infarction; PCI, percutaneous coronary intervention
Discussion
The present study of a large dataset at a single institution provided a unique perspective of the major impact that the changes in technology have had on early outcomes of real‐world practice since DES introduction in PCI. The major finding of this study was that the incidence of in‐hospital MACE—a composite of death, acute MI, and TVR—had sequential, incremental improvements, with a 68% reduction in the real‐world complex population (from 3.1% to 1.0%), despite “sicker” patient profiles over time (as evidenced by higher proportions of comorbid conditions and complex lesions; the probable reason was that the patients transferred from low‐volume community hospitals had a higher incidence of comorbidities over time). In addition, in the past 5 years there were marked reductions in in‐hospital TVR, acute MI, and death.
The improvement in in‐hospital outcome after PCI found in the present study is in agreement with results of other studies that have reported significant improvements in outcomes for patients with various clinical and angiographic characteristics.8, 9, 10, 11, 12 There is a number of possible explanations for incremental improvements of in‐hospital outcome over time in this study. First, the progressively increasing use of DES was concordant with these results, as DES had been confirmed to improve the clinical outcome in previous studies.13, 14, 15, 16 Second, the patients in the recent cohorts having more adverse clinical and angiographic characteristics suggested the improvement in PCI techniques contributed to the improvement in outcomes. However, changes in PCI techniques only partly explained these findings, because the rates of procedural success and procedural complications in the earlier periods, in which the proportion of DES use was only 56.8%, as compared with the later periods in which the proportion of DES surpassed 90%, were similar. Third, the improved outcomes might have resulted from increasing experience in performing this procedure.17 Fourth, in terms of the effect of medical therapy, although the percentages of patients accepted standard drug therapies might have increased over time, however, no major changes have occurred in the interventional practice in the past 5 years.
Our study also demonstrated that the rates of transradial approach in PCI continuously increased in the past 5 years, and the transradial approach was significantly superior to femoral access in terms of the risk of vascular complications. A meta‐analysis of 12 random trials comparing the transradial approach and transfemoral approach proved that the former was associated with a significantly lower rate of entry‐site complications (odds ratio [OR]: 0.20, 95% CI: 0.09–0.42, P < 0.0001); however, the risk of MACE (death, MI, or emergency TVR) was similar in the 2 approaches (OR: 0.92, 95% CI: 0.57–1.48, P = 0.7).18 A recent randomized study reported that transradial coronary angiography and angioplasty were feasible and effective, with similar results to those of the transfemoral approach, while the rate of vascular complications was negligible using the transradial approach (0.58% vs 3.71%).19
Finally, we analyzed the predictors of in‐hospital clinical outcomes in all patients. These analyses confirmed that use of DES is the independent factor associated with a reduction in MACE in the general population. We also showed the predictive value of age ≥ 65 years, prior MI, left main lesion, and dissection during procedure with regard to in‐hospital MACE, which was consistent with previous data.20, 21, 22, 23, 24, 25 Unlike previous studies, age ≥ 65 years was the only clinical characteristic that identified patients at higher risk of in‐hospital MACE. However, angiographic variables were the predominant predictors of in‐hospital MACE. Thus, the occurrence of in‐hospital MACE was a function of poor angiographic outcomes and was less dependent upon clinical factors identified in prior studies, such as gender or a history of diabetes. Indeed, patients with these variables represented a small but very‐high‐risk group of subjects with many comorbidities and risk factors, both presented and acquired during the procedure, which might contribute to the increased rate of MACE.
Study Limitations
The observational, nonrandomized, retrospective analysis is the first limitation of the study. We may not have accounted for potential confounders or other unmeasured covariates. For example, it is difficult to determine the relative importance of better operator skills, improvement in technology, and other adjunctive therapy in the improvement of results in the most recent period. On the other hand, this study carries important and complementary information derived from real‐world practice, given the inclusion of patients and lesions often excluded from randomized trials. Furthermore, the study is limited in providing information only on short‐term outcomes, while longer‐term outcomes are also of great interest. The present results should be considered possible indicators of quality of care that need to be corroborated by follow‐up studies using richer clinical documentation. Finally, the study setting involved a single‐center tertiary‐care referral center, and the results of the present study may not be generalized to low‐volume community hospitals.
Conclusion
Our findings have demonstrated significant improvement in in‐hospital outcomes over time among patients who have undergone PCI since the advent of DES, an improvement that has occurred despite the use of PCI in higher‐risk patients. Our findings indicated that DES deployed mainly decreased the incidence of in‐hospital MACE, as reduction of dissection during the procedure would be accompanied by improvement in in‐hospital outcome.
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