Cardiovascular Intervention and Therapeutics

, Volume 28, Issue 3, pp 242–249

Use of Thrombolysis in Myocardial Infarction Risk Score to predict bleeding complications in patients with unstable angina and non-ST elevation myocardial infarction undergoing percutaneous coronary intervention

Authors

    • Department of CardiologyAshikaga Red Cross Hospital
  • Shun Kohsaka
    • Department of CardiologyKeio University School of Medicine
  • Hiroaki Miyata
    • University of Tokyo, Healthcare Quality Assessment
  • Akio Kawamura
    • Department of CardiologyKeio University School of Medicine
  • Shigetaka Noma
    • Department of CardiologySaiseikai Utsunomiya Hospital
  • Masahiro Suzuki
    • Department of CardiologyNational Hospital Organization, Saitama National Hospital
  • Susumu Nakagawa
    • Department of CardiologySaiseikai Central Hospital
  • Yukihiko Momiyama
    • Department of CardiologyNational Hospital Organization, Tokyo Medical Center
  • Toshiyuki Takahashi
    • Department of CardiologyAshikaga Red Cross Hospital
  • Yuji Sato
    • Center for Clinical ResearchKeio University School of Medicine
  • Keiichi Fukuda
    • Department of CardiologyKeio University School of Medicine
Original Article

DOI: 10.1007/s12928-013-0162-3

Cite this article as:
Numasawa, Y., Kohsaka, S., Miyata, H. et al. Cardiovasc Interv and Ther (2013) 28: 242. doi:10.1007/s12928-013-0162-3

Abstract

Thrombolysis in myocardial infarction (TIMI) is a prognostic score developed for managing the high risk of cardiac events immediately after unstable angina and non-ST elevation myocardial infarction (UA/NSTEMI). In Asian populations that have a higher rate of bleeding complications, data about TIMI score are lacking. Using a Japanese multicenter registry, we investigated the impact of utilizing TIMI score in UA/NSTEMI patients, focusing on bleeding complications. The TIMI score was calculated for 587 patients who underwent percutaneous coronary intervention (PCI) for UA/NSTEMI (2008–2010). They were classified into low-risk (TIMI score 0–2, N = 268, 45.6 %), intermediate-risk (TIMI score 3–4, N = 264, 45.0 %) and high-risk (TIMI score 5–7, N = 55, 9.4 %) groups; patient characteristics for each group were statistically analyzed. The patients in the higher TIMI score group were older (p < 0.001), had lower GFR (p = 0.021) and hemoglobin level after PCI (p < 0.001), and severe coronary disease pattern (p = 0.014 and p = 0.023, respectively, for left main and three-vessel disease). The TIMI score was significantly associated with requirement of blood transfusion (low-risk, moderate-risk, and high-risk groups: 1.1, 4.2, and 7.3 %, respectively; p = 0.021), and the incidence of access site bleeding (1.1, 2.7, and 5.5 %, p = 0.112). The TIMI score might aid in subjectively quantifying the risk of in-hospital complication rates such as access site bleeding.

Keywords

TIMI scorePercutaneous coronary interventionCoronary artery disease

Introduction

Despite the increased use of coronary revascularization, patients with unstable angina (UA)/non-ST elevation myocardial infarction (NSTEMI) remain at risk for subsequent cardiac and arrhythmic events. Therefore, accurate risk stratification is important in patients with complaints suggestive of UA/NSTEMI [1, 2]. Thrombolysis in myocardial infarction (TIMI) score is derived from 7 variables that were determined to be independently predictive of outcomes in patients with UA/NSTEMI and has been validated in predicting short-term prognosis [35]. A higher TIMI risk score correlated significantly with increased numbers of events (all-cause mortality, new or recurrent myocardial infarction, or severe recurrent ischemia requiring revascularization) at 14 days after the initial event.

The TIMI score has been validated for various databases and unselected patients [611]. However, data regarding the TIMI scoring system in Asian populations are lacking. Since the risk profiles and procedural preferences of Asian patients differ from those in Western populations, it is important to review the applicability of the TIMI risk score in the generalized settings in Asian patients.

Coronary artery disease (CAD) patients in Japan have different characteristics as compared to Western patients (e.g., older, smokes frequently, and have fewer traditional risk factors except diabetes), and tend to have more frequent bleeding complications during and after PCI [12, 13]. Recently, bleeding has been indicated as an important prognostic indicator in the modern PCI era [1419], particularly in Asia where patients are more vulnerable to antiplatelet and anticoagulant therapy. The TIMI score has been widely applied in clinical practice; however, its applicability for evaluating the risk of bleeding complications has not been examined.

The aim of this study was therefore to validate the TIMI risk score in predicting in-hospital complications in patients with UA/NSTEMI undergoing PCI using a Japanese multicenter registry.

Materials and methods

Study design

The Japan Cardiovascular Database (JCD) is a large, ongoing, prospective multicenter cohort study designed to record clinical backgrounds and outcome data for PCI patients in Japan [20]. Data for approximately 200 variables are continuously being collected in this study. Participating hospitals are instructed to record data from consecutive hospital visits for PCI and to register these data into an internet-based database system. The internet-based system performs checks to ensure that the reported data are complete and internally consistent. PCI with any commercially available coronary device can be included. The decision to perform PCI is made according to the investigators’ clinical assessment of the patient. The study does not mandate specific interventional or surgical techniques such as vascular access, use of specific stents, or closure devices.

The majority of clinical variables in JCD are defined according to the National Cardiovascular Data Registry (NCDR) sponsored by the American College of Cardiology for conducting comparative research to determine factors that can lead to disparities in PCI management. NCDR is a large PCI registry system with over 1,000,000 entries for ischemic heart disease and over 500,000 entries for PCI collected from more than 500 institutions in the US [21, 22].

Participants

Major teaching hospitals within the metropolitan Tokyo area were selected for the pilot phase of this study, and the study protocol was approved by the institutional review board (IRB) committee at each site. Patients were enrolled based on the cardiac event, and all consecutive PCI procedures during the study period were registered, including failure cases. Patients aged <18 years were excluded from the study. The subgroup of patients that underwent intracoronary infusion of acetylcholine to induce coronary vasospasm was also registered because vasospastic angina accounts for a significant portion of patients with CAD and acute coronary syndrome (ACS) in Japan [23].

Study population

We analyzed data from 587 patients who underwent PCI procedures for UA/NSTEMI performed at 9 Japanese hospitals participating in the JCD registry from September 2008 to August 2010. Patients with STEMI or stable angina were excluded from the present analysis. To reduce patient selection bias, no other specific exclusion criteria were considered. Clinical, angiographic, and procedural complications were prospectively entered into the JCD-KICS registry database. All patients underwent periprocedural anticoagulation via heparin based on institutional dosing instructions during PCI. Usually, a bolus dose of 5,000 to 10,000 IU is given and additional doses are provided based on an ACT level of >300 s. We did not have a mandated protocol for hemostasis after the PCI procedures. Details of post-procedural management were left to the primary operators’ decision.

The TIMI risk score was the sum of 7 dichotomous parameters (1 point for each variable if present: range 0–7) as follows: age ≥65 years, ≥3 risk factors for coronary artery disease, use of aspirin within the past 7 days, known coronary artery stenosis ≥50 %, ≥2 episodes of angina within the past 24 h, ST-segment deviation, and elevated cardiac biomarker levels [5]. Each of these parameters was recorded by clinical coordinators and validated by a single investigator blinded to the remaining patient characteristics as well as the clinical outcome.

The endpoints were defined as in-hospital mortality and other complications. Complications were defined as all complications, severe dissection or coronary perforation, myocardial infarction after PCI, TIMI flow <grade 3, cardiac shock or heart failure, cerebral bleeding or stroke, and bleeding complications. Bleeding complications in this registry were further defined as those requiring blood transfusion and/or prolonging hospital stay and/or causing a decrease in hemoglobin of >3.0 g/dL [24]. Furthermore, bleeding complications were divided into puncture-site bleeding, retroperitoneal bleeding, gastrointestinal bleeding, genitourinary bleeding, or other bleeding. Hematomas measuring >10 cm for femoral access or >2 cm for radial access also qualified as access site bleeding.

Data analysis

Continuous variables are expressed as mean ± standard deviation (SD). Categorical variables are expressed as a percentage. Continuous variables were compared using the Student’s t test, and the differences between categorical variables were examined using the Chi-square test. All statistical calculations and analyses were performed using SPSS version 15 (SPSS, Chicago, IL, USA.). p values of <0.05 were considered statistically significant.

Results

A total of 587 patients who underwent PCI for UA/NSTEMI were analyzed in this study. The mean age was 68.2 ± 10.8 years and 452 patients (77.0 %) were men. A total of 190 patients (32.4 %) were enrolled with NSTEMI, and 397 patients (67.6 %) were UA.

Baseline characteristics

The incidence of each TIMI risk factor in the 587 study patients was 59.3 % for age ≥65 years, 34.6 % for ≥3 risk factors for coronary artery disease, 28.4 % for use of aspirin within the past 7 days, 26.1 % for known coronary artery stenosis ≥50 %, 39.7 % for ≥2 episodes of angina within the past 24 h, 34.4 % for ST-segment deviation, and 28.4 % for elevated cardiac biomarker levels. The distribution of 587 study patients stratified by TIMI risk score is shown in Fig. 1. The median TIMI risk score was 2.51. The patients were classified into low- (TIMI risk score 0–2, N = 268, 45.6 %), intermediate- (TIMI risk score 3–4, N = 264, 45.0 %), and high-risk patients (TIMI risk score 5–7, N = 55, 9.4 %) (Table 1) [25].
https://static-content.springer.com/image/art%3A10.1007%2Fs12928-013-0162-3/MediaObjects/12928_2013_162_Fig1_HTML.gif
Fig. 1

Distribution of UA/NSTEMI patients who underwent PCI based on TIMI risk score

Table 1

Distribution of the patients classified into low-, intermediate-, and high-risk groups based on the TIMI risk score

 

TIMI low-risk (0, 1, 2) N = 268

TIMI moderate-risk (3, 4) N = 264

TIMI high-risk (5, 6, 7) N = 55

p value

Age ≥65 years

88 (32.8)

208 (78.8)

52 (94.5)

<0.001

≥3 risk factors for CAD

37 (13.8)

123 (46.6)

43 (78.2)

<0.001

Use of aspirin (last 7 days)

24 (9.0)

107 (40.5)

36 (65.5)

<0.001

Known CAD (prior stenosis ≥50 %)

20 (7.5)

96 (36.4)

37 (67.3)

<0.001

≥2 episodes of angina in <24 h

53 (19.8)

142 (53.8)

38 (69.1)

<0.001

ST segment deviation

32 (11.9)

123 (46.6)

47 (85.5)

<0.001

Elevated cardiac biomarkers

35 (13.1)

93 (35.2)

39 (70.9)

<0.001

Values are presented as n (%)

CAD coronary artery disease

The baseline clinical characteristics of 587 study patients according to the TIMI risk score are shown in Table 2. The patients in the higher TIMI risk score group were older (p < 0.001), shorter (p = 0.003), had lower GFR (p = 0.021), and lower hemoglobin levels before and after PCI (p = 0.001 and p < 0.001, respectively). A higher prevalence of risk factors such as hypertension (p < 0.001), hyperlipidemia (p < 0.001), and diabetes mellitus (p < 0.001) along with a higher rate of previous PCI (p < 0.001) and previous coronary artery bypass graft surgery (p = 0.024) was noted in the higher TIMI risk group as compared to the lower TIMI risk group.
Table 2

Baseline clinical characteristics in TIMI low-, moderate-, and high-risk groups

 

TIMI low-risk (0, 1, 2) N = 268

TIMI moderate-risk (3, 4) N = 264

TIMI high-risk (5, 6, 7) N = 55

p value

Age, years

65.4 ± 11.9

70.1 ± 9.4

73.1 ± 7.7

<0.001

Male sex (%)

218 (81.3)

194 (73.5)

40 (72.7)

0.072

Height (cm)

162.8 ± 8.4

161.1 ± 8.2

159.0 ± 7.6

0.003

Weight (kg)

64.1 ± 12.8

62.1 ± 11.1

60.9 ± 10.4

0.072

BMI (kg/m2)

24.0 ± 3.8

23.8 ± 3.4

24.0 ± 3.5

0.748

Hypertension

172 (64.2)

204 (77.3)

52 (94.5)

<0.001

Hyperlipidemia

155 (57.8)

181 (68.6)

48 (87.3)

<0.001

Diabetes mellitus

90 (33.6)

120 (45.5)

35 (63.6)

<0.001

Insulin-dependent

20 (7.5)

29 (11.0)

11 (20.0)

0.017

Smoking

90 (33.6)

73 (27.7)

10 (18.2)

0.050

Previous PCI

59 (22.0)

90 (34.1)

35 (63.6)

<0.001

Previous CABG

11 (4.1)

23 (8.7)

7 (12.7)

0.024

Previous HF

16 (6.0)

17 (6.4)

5 (9.1)

0.692

Previous MI

36 (13.4)

65 (24.6)

26 (47.3)

<0.001

CVD

14 (5.2)

28 (10.6)

3 (5.5)

0.053

PAD

15 (5.6)

24 (9.1)

8 (14.5)

0.057

COPD

4 (1.5)

12 (4.5)

3 (5.5)

0.086

Non-STEMI

92 (34.3)

74 (28.0)

24 (43.6)

0.052

Unstable angina

176 (65.7)

190 (72.0)

31 (56.4)

0.052

Cardiogenic shock

6 (2.2)

2 (0.8)

1 (1.8)

0.374

GFR

88.1 ± 32.3

85.4 ± 34.0

74.5 ± 31.9

0.021

Hemoglobin (Pre-PCI)

13.4 ± 2.0

13.0 ± 2.1

12.5 ± 2.0

0.001

Hemoglobin (Post-PCI)

12.3 ± 2.0

11.8 ± 2.1

11.0 ± 2.0

<0.001

Creatinine (Pre-PCI)

1.31 ± 2.04

1.30 ± 1.86

1.42 ± 1.68

0.913

Creatinine (Post-PCI)

1.34 ± 2.02

1.33 ± 1.88

1.43 ± 1.46

0.942

Hemodialysis

9 (3.4)

11 (4.2)

3 (5.5)

0.737

Antiplatelet agents

 Aspirin

260 (97.0)

257 (97.3)

54 (98.2)

0.885

 Clopidogrel

172 (64.2)

172 (65.2)

37 (67.3)

0.851

 Ticlopidine

8 (3.0)

8 (3.0)

4 (7.3)

0.274

 Cilostazol

0 (0)

4 (1.5)

0 (0)

0.191

Values are presented as n (%) or mean ± SD, as indicated

BMI body mass index, CAD coronary artery disease, PCI percutaneous coronary intervention, CABG coronary artery bypass grafting, HF heart failure, MI myocardial infarction, CVD cerebrovascular disease, PAD peripheral artery disease, COPD chronic obstructive pulmonary disease, STEMI ST elevation myocardial infarction, GFR glomerular filtration rate

Angiographical and procedural data

Angiographical and procedural data are shown in Table 3. The patients in the higher TIMI score group had a severe coronary disease pattern, such as left main trunk lesion (p = 0.014) and three-vessel disease (0.023). Anatomical characteristics, such as bifurcation lesions, type C lesions, chronic total occlusion lesions, and total X-ray time did not differ significantly among the TIMI low-, intermediate-, and high-risk groups.
Table 3

Angiographical and procedural data in TIMI low-, moderate-, and high-risk groups

 

TIMI low-risk (0, 1, 2) N = 268

TIMI moderate-risk (3, 4) N = 264

TIMI high-risk (5, 6, 7) N = 55

p value

Two-vessel disease

117 (43.7)

135 (51.1)

32 (58.2)

0.070

Three-vessel disease

58 (21.6)

79 (29.9)

20 (36.4)

0.023

Bifurcation lesion

60 (22.4)

57 (21.6)

17 (30.9)

0.317

LMT lesion

24 (9.0)

39 (14.8)

12 (21.8)

0.014

CTO lesion

14 (5.2)

15 (5.7)

0 (0)

0.201

Type C lesion

72 (26.9)

80 (30.3)

16 (29.1)

0.678

Femoral approach

212 (79.1)

206 (78.0)

44 (80.0)

0.927

Radial approach

47 (17.5)

51 (19.3)

9 (16.4)

0.809

Drug-eluting stent

118 (44.0)

125 (47.3)

25 (45.5)

0.744

Bare metal stent

82 (30.6)

64 (24.2)

12 (21.8)

0.171

POBA

14 (5.2)

19 (7.2)

7 (12.7)

0.125

IVUS use

79 (29.5)

84 (31.8)

23 (41.8)

0.200

Hemostat devices

51 (19.0)

54 (20.5)

6 (10.9)

0.258

Total X-ray time

29.1 ± 18.1

33.7 ± 22.1

31.7 ± 21.7

0.052

Values are presented as n (%) or mean ± SD, as indicated

CAD coronary artery disease, LMT left main trunk, CTO chronic total occlusion, POBA plain old angioplasty, IVUS intravascular ultrasound

In-hospital outcomes

The rates of in-hospital complications are listed in Table 4. The patients from the higher TIMI score group tended to have a higher complication rate (total complications for low-, moderate-, and high-risk TIMI score groups 10.8, 14.4, and 18.2 %, respectively, p = 0.240). The in-hospital mortality rate did not differ significantly among the TIMI low-, intermediate-, and high-risk groups (p = 0.411). Importantly, patients with a higher TIMI score had significantly higher event rates for receiving blood transfusion (1.1, 4.2, and 7.3 %, p = 0.021), and tended to have a higher rate of access site bleeding (1.1, 2.7 and 5.5 %, p = 0.112) as well as reduced- or no-reflow pattern after PCI (2.6, 5.7 and 9.1 %, p = 0.059).
Table 4

Complications in TIMI low-, moderate-, and high-risk groups

 

TIMI low-risk (0, 1, 2) N = 268

TIMI moderate-risk (3, 4) N = 264

TIMI high-risk (5, 6, 7) N = 55

p value

Total complications

29 (10.8)

38 (14.4)

10 (18.2)

0.240

In-hospital mortality

5 (1.9)

3 (1.1)

2 (3.6)

0.411

Severe dissection

3 (1.1)

2 (0.8)

0 (0)

0.695

Coronary perforation

0 (0)

3 (1.1)

0 (0)

0.158

Myocardial infarction after PCI

11 (4.1)

9 (3.4)

3 (5.5)

0.759

TIMI flow <3

7 (2.6)

15 (5.7)

5 (9.1)

0.152

Cardiac shock

4 (1.5)

4 (1.5)

2 (3.6)

0.508

Cardiac tamponade

0 (0)

0 (0)

0 (0)

 

Cerebral bleeding/infarction

0 (0)

0 (0)

0 (0)

 

Bleeding complications within 72 h

11 (4.1)

15 (5.7)

4 (7.3)

0.531

Puncture site bleeding

3 (1.1)

7 (2.7)

3 (5.5)

0.112

Puncture site hematoma

6 (2.2)

6 (2.3)

2 (3.6)

0.815

Gastrointestinal bleeding

1 (0.4)

3 (1.1)

0 (0)

0.458

Genitourinary bleeding

0 (0)

1 (0.4)

0 (0)

0.542

Other bleeding

3 (1.1)

3 (1.1)

2 (3.6)

0.311

Blood transfusion

3 (1.1)

11 (4.2)

4 (7.3)

0.021

Values are presented as n (%)

PCI percutaneous coronary intervention

Discussion

The major findings of this study demonstrate higher TIMI risk scores were associated with a higher in-hospital complication rate in the Japanese multicenter contemporary PCI registry, particularly those related to bleeding, such as the rate of receiving blood transfusions and access site bleeding, along with reduced- or no-reflow pattern after PCI.

Early risk stratification plays a pivotal role in the optimal management of UA/NSTEMI patients. The ACC/AHA and the ESC consensus guidelines recognize the importance of early risk stratification in the management of patients with UA/NSTEMI, and recommend an integrated approach to risk assessment [1, 2]. Although the TIMI risk score was originally described as a useful tool for predicting the composite endpoint of mortality, recurrent myocardial infarction, and repeat revascularization at 14 days in patients with UA/NSTEMI, our study investigated its use in predicting bleeding complications in a multicenter Japanese PCI registry base in an unselected population in contemporary practice.

The usefulness of predictive scores in clinical medicine depends on whether it informs clinicians and patients by reliably identifying groups with a specific prognosis or requirement for treatment. Some previous studies have reported that bleeding complications after PCI are notably associated with increased mortality [1419]. Bleeding is more frequently observed in Asian populations [13], and the prediction of such complications after PCI aids in assessing long-term prognosis and the safety of using antiplatelet agents and anticoagulants.

Although the TIMI score was developed more than 10 years ago, following the continuous developments in the management of ACS, this score has been validated in multiple trials and settings [611, 25], including its use in the emergency department [26, 27]. On the other hand, the difficulties associated with such combined endpoints have also been previously reported, especially with respect to a regional treatment bias including the availability of catheterization [28]. In Japan, primary PCI facilities are available throughout the country because of a socialized medical system. This enables more timely access to revascularization for high-risk patients with UA/NSTEMI. As a result, most of the patients with UA/NSTEMI are treated by PCI in Japan. Since coronary artery disease patients in Japan have different characteristics as compared to Western patients, and medical circumstances differ between Japan and Western countries, it is important to investigate the impact of the TIMI risk score in generalized real-world settings in Japan.

This study was not a strict validation of the TIMI risk score in the manner in which it was derived in the original study. Although the TIMI risk score has been validated as predictive for 14-day outcomes [5], we investigated the total in-hospital complications. Besides, the TIMI score has been used to predict risks of the patients with UA/NSTEMI, not only for patients undergoing PCI. In this study, all patients with UA/NSTEMI who underwent PCI were analyzed. Our data did not include the patients with UA/NSTEMI who were candidates for CABG or conservative medical therapy.

Although in-hospital mortality rate did not differ between each risk group, the higher TIMI risk score was significantly associated with requirement of blood transfusion and the incidence of access site bleeding in this study. Blood transfusion in anemic patients with ischemic heart disease may theoretically increase oxygen delivery. However, some previous studies reported that blood transfusion may lead to adverse outcomes after percutaneous coronary intervention [2931]. Blood transfusion is widely recognized as potentially harmful because of the risk of acute allergic reaction, hemolysis, transmissible infection, acute lung injury, and immune suppression [30, 32]. Moreover, there are some potentially harmful effects of a blood transfusion on cardiac function such as increased blood viscosity, free radical production, fluid overload, electrolyte imbalance, and hypothermia [29]. However, the relationship between blood transfusion and adverse outcomes including mortality after percutaneous coronary intervention has not been proven to be either a cause or effect.

Kinnarid et al. [29] reported that the need for a blood transfusion after percutaneous coronary intervention, independent of the bleeding episode, was associated with increased in-hospital and 1-year mortality. Jani et al. [30] reported that blood transfusion in anemic patients undergoing percutaneous coronary intervention for myocardial infarction was associated with a higher risk of in-hospital mortality after adjustment for comorbidities and propensity for transfusion. On the other hand, Valente et al. [33] reported that transfused patients with ST elevation myocardial infarction showed a higher mortality rate than that of non-transfused patients; however, blood transfusion itself was not associated with early death when adjusted for the propensity score.

There remains the possibility that bleeding complication requiring blood transfusion is in part a marker of patients at high risk for mortality. Patients who required blood transfusion presented more often with severe comorbidities [30, 31]. In those previous studies, many factors involved in the clinical decision for blood transfusion might not be adjusted for in the statistical model.

In this study, the patients in higher TIMI score group had lower GFR and hemoglobin levels after PCI, along with severe coronary disease patterns such as left main trunk lesion and three-vessel disease. Some previous studies have reported that renal failure is associated with the increased risk of bleeding complications after PCI [3437]. Hanna et al. [37] reported that patients with chronic kidney disease presenting with NSTEMI and managing with PCI have a greater number of comorbidities, such as history of myocardial infarction, heart failure, and three-vessel disease. They also reported that chronic kidney disease was strongly associated with in-hospital mortality and bleeding in patients with NSTEMI undergoing PCI, which is in concordance with our present results. The bleeding risk increased in renal failure due to impaired platelet adhesiveness. In our study, the patients in the higher TIMI score group had lower GFR, and it is possible that renal insufficiency is associated with a higher rate of bleeding complications after PCI.

There is not much information available regarding how often risk assessment is actually performed using risk scores in patients with UA/NSTEMI. Physicians may be reluctant to use such risk scores at the bedside because they find it inconvenient and time-consuming. However, a clinical diagnosis of suspected ACS patients has low diagnostic accuracy when based on the ECG and clinical symptoms [38, 39]. Previous studies have reported that these risk scores provide additional prognostic value beyond risk assessment by physicians [8].

Previous studies have reported that the GRACE score allows better discrimination for in-hospital and 1-year mortality in patients with ACS than TIMI risk score [7, 8, 3941]. However, the GRACE score is slightly more complex than TIMI risk score. A risk stratification tool needs to be simple, easily applicable early in the clinical course, and uses information available during the acute presentation. The TIMI risk score is a valuable and simple tool for clinicians to stratify patients at presentation using only history, initial electrocardiogram, and cardiac marker levels. The TIMI risk score is the simplest and commonest tool for risk assessment, and efforts aimed at accurate risk stratification may improve the overall patient care process and medical resource utilization.

Study limitations

First, the study population was of limited size as compared to the number of sites included in our registry. Despite a large number of PCI procedures performed (>200,000 annually), the number of procedures performed in each individual hospital is limited in Japan. Second, Japanese patients are known to have higher bleeding complication rates, and these clinical characteristics may have enhanced the effectiveness of the TIMI risk score in the present study. Further research in a larger population and preferably in other countries is desirable.

Conclusions

The TIMI risk score might be helpful in subjectively quantifying the risk of in-hospital complication rates such as access site bleeding.

Acknowledgments

We appreciate all the investigators, clinical coordinators and institutions involved in the JCD-KICS study. This research was supported by a grant from the Ministry of Education, Culture, Sports, Science, and Technology, Japan (KAKENHI No. 21790751). Investigators Sonhan Yun, and Toshiyuki Takahashi (Ashikaga Red Cross Hospital); Yutaka Okada and Takashi Koyama (Eiju General Hospital); Soushin Inoue (Hino Municipal Hospital); Kimi Koide and Masaru Shibata (Hiratsuka City Hospital); Shunsuke Takagi (Isehara Kyodo Hospital); Keishu Li and Koichiro Sueyoshi (Kawasaki City Municipal Hospital); Masashi Takahashi, Yohei Ohno, Takahide Arai, Shinsuke Yuasa, Yuichiro Maekawa and Akio Kawamura (Keio University School of Medicine); Masahiro Suzuki (National Hospital Organization Saitama National Hospital); Yukinori Ikegami and Yukihiko Momiyama (National Hospital Organization Tokyo Medical Center); Ayaka Endo, Toshiyuki Takahashi and Susumu Nakagawa (Saiseikai Central Hospital); Takashi Yagi, Takeshi Onitsuka and Shigetaka Noma (Saiseikai Utsunomiya Hospital); Shiro Ishikawa (Saitama City Hospital); Atsushi Mizuno, Shuzo Nishihara, Hitoshi Anzai and Yutaro Nishi (St Luke’s International Hospital Heart Center); Takahiro Oki (Tokyo Dental College Ichikawa General Hospital). Clinical coordinators Fumika Tamura, Junko Susa, Hiroe Fukuda, Ayano Ishikawa, Shuko Oonuki and Ikuko Ueda.

Copyright information

© Japanese Association of Cardiovascular Intervention and Therapeutics 2013