Decreased Glomerular Filtration Rate is an Independent Predictor of In-Hospital Mortality in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention.

Abstract

Patients with renal dysfunction (RD) experience worse prognosis after myocardial infarction (MI). The aim of the present study was to investigate the impact of admission estimated glomerular filtration rate (eGFR) on clinical outcomes of patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation MI (STEMI).
We retrospectively evaluated 4,542 eligible patients from the Korea Acute Myocardial Infarction Registry (KAMIR). Patients were divided into three groups according to eGFR (mL/min/1.73 m(2)): normal renal function (RF) group (eGFR ≥60, n=3,515), moderate RD group (eGFR between 30 to 59, n=894) and severe RD group (eGFR <30, n=133). Baseline characteristics, angiographic and procedural results, and in-hospital outcomes between the three groups were compared.
Age, gender, Killip class ≥3, hypertension, diabetes, congestive heart failure, peak creatine kinase-MB, high sensitivity C-reactive protein, B-type natriuretic peptide, left ventricle ejection fraction, multivessel disease, infarct-related artery and rate of successful PCI were significantly different between the 3 groups (p<0.05). With decline in RF, in-hospital complications developed with an increasing frequency (14.1% vs. 31.8% vs. 45.5%, p<0.0001). In-hospital mortality rate was significantly higher in the moderate and severe RD groups as compared to the normal RF group (2.3% vs. 13.9% vs. 25.6%, p<0.0001). Using multivariate logistic regression analysis, adjusted odds ratio for in-hospital mortality was 2.67 {95% confidence interval (CI) 1.44-4.93, p=0.002} in the moderate RD group, and 4.09 (95% CI 1.48-11.28, p=0.006) in the severe RD group as compared to the normal RF group.
Decreased admission eGFR was associated with worse clinical courses and it was an independent predictor of in-hospital mortality in STEMI patients undergoing primary PCI.

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184
Print ISSN 1738-5520 / On-line ISSN 1738-5555
Copyright © 2011 The Korean Society of Cardiology
ORIGINAL ARTICLE
DOI 10.4070/kcj.2011.41.4.184
Open Access
Decreased Glomerular Filtration Rate is an Independent Predictor
of In-Hospital Mortality in Patients With ST-Segment Elevation
Myocardial Infarction Undergoing Primary
Percutaneous Coronary Intervention
Joon Young Kim, MD1, Myung Ho Jeong, MD2, Yong Keun Ahn, MD2, Jae Hyun Moon, MD1, Shung Chull Chae, MD3,
Seung Ho Hur, MD4, Taek Jong Hong, MD5, Young Jo Kim, MD6, In Whan Seong, MD7, In Ho Chae, MD8,
Myeong Chan Cho, MD9, Chong Jin Kim, MD10, Yang Soo Jang, MD11, Junghan Yoon, MD12, Ki Bae Seung, MD13,
Seung Jung Park, MD14, and Other Korea Acute Myocardial Infarction Registry Investigators
1St. Carollo Hospital, Suncheon, 2Chonnam National University, Gwangju, 3Kyungpook National University, Daegu,
4Keimyung University Dongsan Medical Center, Daegu, 5Pusan National University Hospital, Busan,
6Yeungnam University Hospital, Daegu, 7Chungnam National University Hospital, Daejon,
8Seoul National University Bundang Hospital, Seongam, 9Chungbuk National University, Cheongju,
10Kyunghee University Hospital, Seoul, 11Yonsei University Hospital, Seoul, 12Wonju University Hospital, Wonju,
13Catholic University Hospital, Seoul, 14Asan Medical Center, Seoul, Korea
ABSTRACT
Background and Objectives: Patients with renal dysfunction (RD) experience worse prognosis after myocardial infarction
(MI). The aim of the present study was to investigate the impact of admission estimated glomerular filtration rate (eGFR) on
clinical outcomes of patients undergoing primary percutaneous coronary intervention (PCI) for ST-segment elevation MI
(STEMI). Subjects and Methods: We retrospectively evaluated 4,542 eligible patients from the Korea Acute Myocardial
Infarction Registry (KAMIR). Patients were divided into three groups according to eGFR (mL/min/1.73 m2): normal renal
function (RF) group (eGFR ≥60, n=3,515), moderate RD group (eGFR between 30 to 59, n=894) and severe RD group (eGFR
<30, n=133). Baseline characteristics, angiographic and procedural results, and in-hospital outcomes between the three groups
were compared. Results: Age, gender, Killip class ≥3, hypertension, diabetes, congestive heart failure, peak creatine kinase-MB,
high sensitivity C-reactive protein, B-type natriuretic peptide, left ventricle ejection fraction, multivessel disease, infarct-relat-
ed artery and rate of successful PCI were significantly different between the 3 groups (p<0.05). With decline in RF, in-hospital
complications developed with an increasing frequency (14.1% vs. 31.8% vs. 45.5%, p<0.0001). In-hospital mortality rate was
significantly higher in the moderate and severe RD groups as compared to the normal RF group (2.3% vs. 13.9% vs. 25.6%,
p<0.0001). Using multivariate logistic regression analysis, adjusted odds ratio for in-hospital mortality was 2.67 {95% confi-
dence interval (CI) 1.44-4.93, p=0.002} in the moderate RD group, and 4.09 (95% CI 1.48-11.28, p=0.006) in the severe RD
group as compared to the normal RF group. Conclusion: Decreased admission eGFR was associated with worse clinical
courses and it was an independent predictor of in-hospital mortality in STEMI patients undergoing primary PCI. (Korean
Circ J 2011;41:184-190)
KEY WORDS: Glomerular filtration rate; Acute myocardial infarction; Mortality; Percutaneous coronary intervention.
Received: May 5, 2010 / Revision Received: July 9, 2010 / Accepted: July 23, 2010
Correspondence: Myung Ho Jeong, MD, Principal Investigator of Korea Acute Myocardial Infarction Registry, The Heart Research Center Designated by
Korea Ministry of Health and Welfares, Chonnam National University Hospital, 671 Jaebong-ro, Dong-gu, Gwangju 501-757, Korea
Tel: 82-62-220-6243, Fax: 82-62-228-7174, E-mail: myungho@chollian.net
• The authors have no financial conflicts of interest.
cc This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licens-
es/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Joon Young Kim, et al. 185
Introduction
Renal dysfunction is a strong risk factor for cardiovascular
disease in the general population,1) and it is associated with
an increased risk of death and cardiovascular events in pa-
tients with a broad range of cardiovascular diseases, includ-
ing heart failure,2) stable coronary artery disease undergoing
percutaneous coronary intervention (PCI)3)4) and acute cor-
onary syndromes.5)6)
In the setting of acute myocardial infarction (AMI), mor-
tality risk is increased in patients with renal dysfunction (RD)
of any degree of severity.7-9) Primary PCI is the best reperfu-
sion strategy for AMI patients and its mortality benefit has
been shown in randomized trials.10-12) However, most of these
trials frequently excluded patients with RD, and few studies
examining the outcomes of AMI patients with RD undergo-
ing primary PCI have been reported.
To date, several studies evaluating the in-hospital prognos-
tic significance of RD in patients undergoing primary PCI for
AMI have reported that RD is an independent predictor of in-
hospital mortality,13-15) even in the case of a successful PCI.13)14)
However, one of these studies13) used serum creatinine level
to determine RD despite the fact that serum creatinine level
can be unreliable as an estimate of renal function (RF), while
the other studies14)15) included a small number of patients and
divided patients according to their RF into merely 2 groups
which is insufficient for RD risk stratification. The aim of the
present study was to investigate the impact of admission esti-
mated glomerular filtration rate (GFR) on in-hospital out-
comes in patients with ST-segment elevation myocardial in-
farction (STEMI) undergoing primary PCI using data from
the Korea Acute Myocardial Infarction Registry (KAMIR).
Subjects and Methods
Korea Acute Myocardial Infarction Registry
KAMIR is a Korean prospective multicenter online regis-
try designed to reflect “real-world” practice trends for patients
presenting with AMI in the recent reperfusion era; the regis-
try has been supported by the Korean Circulation Society
since November 2005. Online registry of AMI cases (www.
kamir.or.kr) has been performed at 41 universities or com-
munity hospitals that are high-volume centers with facilities
for primary PCI and onsite cardiac surgery. Data were col-
lected at each site by a trained study coordinator using a stan-
dardized case report form, and registered and submitted from
individual institutions via password-protected internet-based
electronic case report forms. The study protocol was approved
by the ethics committee at each participating institution.
Study population
From January 2006 to December 2007, a total of 7,895 ST-
EMI patients were registered in KAMIR. Of these, 864 pa-
tients were excluded from this study because they had re-
ceived fibrinolytic therapy and 2,407 patients were excluded
because they did not undergo PCI as the primary treatment
strategy; an additional 82 patients were excluded due to miss-
ing data needed to calculate estimated GFR. The remaining
4,542 patients were eligible for the present study (Fig. 1). Data
on clinical, angiographic and in-hospital outcomes were col-
lected.
The mean age of the study patients was 62.2±12.8 years,
and 3,355 (73.8%) patients were males. The mean estimated
GFR was 78.3 mL/min/1.73 m2. The angiographic success rate
was 91.8%, and the overall in-hospital mortality rate was 5.3%.
Definitions
STEMI was defined by the presence of new ST-segment el-
evation of at least 1 mm (0.1 mV) in 2 contiguous leads or new
left bundle-branch block on the index or subsequent electro-
cardiogram with at least 1 positive cardiac biochemical mark-
er of necrosis. Presence of left main coronary artery stenosis
was defined as a luminal stenosis ≥50%. Primary PCI was
defined as percutaneous coronary revascularization within 24
hours of symptom onset without antecedent treatment with
a fibrinolytic agent as the initial therapy. Successful PCI was
defined as thrombolysis in myocardial infarction 3 flow with
residual stenosis ≤50% in the infarct-related artery. Major ble-
eding was defined as intracranial bleeding, bleeding associ-
ated with the need for blood transfusion, or any other clini-
cally relevant bleeding as judged by the investigator.
Assessment of renal function
RF was defined by estimated GFR, which was calculated by
Excluding patients
who received fibrinolysis (n=864)
Excluding patients
who underwent PCI not by primary strategy (n=2,407)
Excluding missing value
including age and creatinine (n=82)
KAMIR (January 2006 to December 2007)
STEMI on final diagnosis (n=7,895)
STEMI patients who underwent PCI (n=7,031)
STEMI patients who underwent primary PCI
within 24 hours of symptom onset (n=4,624)
Eligible patients (n=4,542)
Fig. 1. Study flow chart. STEMI: ST-segment elevation myocardi-
al infarction, KAMIR: Korea Acute Myocardial Infarction Registry,
PCI: percutaneous coronary intervention.

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186 Estimated GFR as a Predictor in AMI Patients Undergoing Primary PCI
the Modification of Diet in Renal Disease equation (MDRD)16)
from the serum creatinine level measured on admission. The
patients were classified into 3 groups according to the estimat-
ed GFR. Normal RF, moderate and severe RD were defined as
estimated GFR ≥60 mL/min/1.73 m2, between 30 to 59 mL/
min/1.73 m2 and <30 mL/min/1.73 m2, respectively.
Statistical analysis
All analyses were performed using Statistical Package for
the Social Sciences (SPSS) software version 17.0 (SPSS Inc,
Chicago, IL, USA). Data are presented as mean±standard
deviation or median with interquartiles for continuous variables,
and as frequency for categorical variables. Comparisons be-
tween continuous variables were done using one-way analysis
of variance or the Kruskal-Wallis test, while the Pearson’s chi-
square test was used for categorical variables. Logistic regress-
ion analyses were performed to determine predictors of in-hos-
pital mortality. A probability value of p<0.05 was considered
significant.
Table 1. Baseline clinical characteristics
Estimated GFR
30-60 mL/min/1.73 m2
(n=894)
p
≥60 mL/min/1.73 m2
(n=3,515)
<30 mL/min/1.73 m2
(n=133)
Demographic characteristics
Age (years)
Male gender (%)
BMI (kg/m2)
Admission characteristics
SBP (mmHg)
HR (beats/min)
Killip class (%)
1
2
3
4
Killip class ≥3 (%)
Symptom-to-door time (minutes)*
Door-to-balloon time (minutes)*
Medical history (%)
Hypertension
Diabetes
Hyperlipidemia†
Current smoking
Family history of heart disease
Previous MI
Previous CABG
Congestive heart failure
Creatinine (mg/dL)
GFR (mL/min/1.73 m2)
Peak CK-MB (IU/L)*
hs-CRP (mg/L)*
BNP (pg/mL)*
LV ejection fraction (%)
Heparin‡
GP IIb/IIIa inhibitor
*Data are presented as the median with 25-75 percentiles, †Hyperlipidemia was defined as total cholesterol ≥220 mg/dL, ‡Heparin means low-
molecular weight heparin or unfractionated heparin. GFR: glomerular filtration rate, BMI: body mass index, SBP: systolic blood pressure, HR:
heart rate, PCI: percutaneous coronary intervention, MI: myocardial infarction, CABG: coronary artery bypass graft surgery, CK-MB: creatine
kinase MB fraction, BNP: B-type natriuretic peptide, hs-CRP: high sensitivity C-reactive protein, GP: glycoprotein
059.9±12.4
79.0
24.1±3.1
070.1±10.3
56.8
23.7±3.1
069.6±12.7
52.6
23.5±3.5
<0.001
<0.001
0.005
127.4±28.7
075.7±18.7
114.8±34.7
073.3±24.7
109.7±33.5
076.9±27.5
<0.001
0.005
<0.001
77.6
13.0
04.9
04.4
09.3
61.0
15.6
09.4
14.0
23.4
60.5
08.5
10.1
20.9
31.0 <0.001
0.102
0.038
150 (72-287)
085 (60-127)
170 (73-309)
091 (64-136)
112 (46-223)
110 (69-138)
40.1
20.3
18.6
53.5
07.8
27.9
03.1
00.4
61.4
32.7
16.6
30.2
04.0
25.6
04.0
02.0
67.4
42.1
16.9
32.6
00.8
32.0
04.0
01.5
<0.001
<0.001
0.373
<0.001
<0.001
0.773
0.883
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
<0.001
0.042
0.745
00.93±0.18
087.9±41.3
198 (73-300)
0.53 (0.14-1.95)
58 (18-204)0
051.2±11.3
58.5
21.6
01.37±0.26
49.6±7.9
144 (33-273)
0.50 (0.12-1.98)
128 (30-494)
048.7±12.6
14.1
05.8
05.60±6.57
17.5±9.1
159 (51-251)
1.23 (0.12-5.49)
211 (51-797)
048.4±12.9
02.3
00.8

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Joon Young Kim, et al. 187
Results
Baseline clinical characteristics
A total 1,027 (22.6%) patients had at least moderate RD. Pa-
tients with RD were older, were more often females and had
lower BMI values. Also, they were more likely to have lower
systolic blood pressure, increased heart rate and higher Killip
class at presentation. Pre-hospital delay time was similar in
the RD group and the normal RF group, but door-to-balloon
time was longer in the RD group as compared to the normal
RF group. On medical history, they were more likely to have
hypertension, diabetes and congestive heart failure. With re-
spect to laboratory findings, high sensitivity C-reactive pro-
tein and B-type natriuretic peptide levels were higher in the
RD group, but peak creatine kinase-MB level and left ventric-
ular ejection fraction were lower in the RD group as com-
pared to the normal RF group. Use of both heparin and GP
IIb/IIIa inhibitor was lower in the RD group as compared to
the normal RF group (Table 1).
Angiographic and procedural characteristics
Patients with RD were more likely to have multivessel dis-
ease and left main coronary artery stenosis. The location of
infarct-related artery was significantly different in the three
groups, according to their RF. While involvement of the left
anterior descending coronary artery was less frequent, invol-
vement of the right coronary artery was more frequent in the
severe RD group. Also, rate of successful PCI decreased sig-
nificantly as RF declined; however, rate of stent insertion re-
mained similar in all the three groups (Table 2).
Table 2. Angiographic and procedural characteristics
Estimated GFR
30-60 mL/min/1.73 m2
(n=894)
p
≥60 mL/min/1.73 m2
(n=3,515)
<30 mL/min/1.73 m2
(n=133)
No. of diseased vessels (%)
1
2
3
Presence of LM stenosis (%)
Location of infarct-related artery (%)
LM
LAD
LCX
RCA
Type of lesion (%)
A/B1
B2/C
Rate of successful PCI (%)
Rate of stent use (%)
LM: left main, LAD: left anterior descending, LCX: left circumflex, RCA: right coronary artery
<0.001
51.8
30.0
18.2
01.4
37.0
34.8
28.2
03.3
31.8
35.6
32.6
04.5 <0.001
<0.001
03.8
17.3
26.6
52.2
03.9
16.5
25.0
54.6
04.1
12.3
18.9
64.8
0.408
16.4
61.1
93.1
94.3
04.0
15.7
87.7
93.0
00.5
02.4
87.2
93.0
<0.001
0.315
Table 3. Incidence of in-hospital complications
Estimated GFR
30-60 mL/min/1.73 m2
(n=894)
31.8
07.0
05.8
02.1
14.1
02.0
01.8
01.9
p
≥60 mL/min/1.73 m2
(n=3,515)
14.1
02.6
03.4
01.1
04.3
00.9
00.1
00.3
<30 mL/min/1.73 m2
(n=133)
45.5
08.3
06.0
04.5
19.5
03.0
06.0
04.8
Complications (%)
AV block
VT/VF
Atrial fibrillation
Cardiogenic shock
Ischemic event*
Acute renal failure†
Major bleeding
*Ischemic event includes recurrent ischemia, re-infarction and cerebrovascular event, †Acute renal failure requiring renal replacement thera-
py. AV block: atrioventricular block, VT: ventricular tachycardia, VF: ventricular fibrillation
<0.001
<0.001
0.002
0.001
<0.001
0.005
<0.001
<0.001

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188 Estimated GFR as a Predictor in AMI Patients Undergoing Primary PCI
Clinical outcomes
In-hospital complications, including arrhythmia, cardioge-
nic shock, ischemic events, acute renal failure and major ble-
eding, developed more frequently in patients with RD (Table
3). In-hospital mortality rates increased significantly as esti-
mated GFR decreased (p<0.001), and approximately one-four-
th of the patients (25.6%) in the severe RD group died (Fig. 2).
Although the main cause of in-hospital mortality was pump
failure (p<0.001), frequencies of the causes of mortality were
not significantly different between the three groups (p=0.165)
(Table 4). On multivariate logistic regression analysis, age,
diabetes, Killip class ≥3, successful PCI and left ventricular
ejection fraction were identified as independent predictors of
in-hospital mortality. In addition, decreased estimated GFR
was also identified as a powerful independent predictor of in-
hospital mortality. When compared with the normal RF group,
adjusted OR was 2.67 {95% confidence interval (CI): 1.44 to
4.93; p=0.002} in the moderate RD group and 4.09 (95% CI:
1.48 to 11.28; p=0.006) in the severe RD group (Table 5).
Discussion
The main finding of the present study is that RD defined by
estimated GFR at admission is an independent predictor of in-
hospital mortality in patients with STEMI undergoing pri-
mary PCI; this increased mortality risk was observed not only
(%)
in the patients with severe RD but also in the patients with mo-
derate RD.
In the present study, RD was defined by estimated GFR cal-
culated using the MDRD equation, which is currently recom-
mended in clinical practice,17) and patients were divided into
three groups. Although RD, as defined by either serum creati-
nine level or estimated GFR, has been associated with in-
creased mortality in patients with AMI,13-15)18)19)21) serum cre-
atinine level is insensitive for an early detection of RD and
could underestimate the incidence of moderate or severe RD
concealed behind the near-normal creatinine levels,9)22)23) th-
ereby underscoring the risk of RD in AMI patients. Further-
more, a graded risk of RD clearly exists, RF should be classifi-
ed into at least 3 groups using estimated GFR for appropriate
RD risk stratification in clinical practice. Our study on the
basis of estimated GFR, showed that patients with moderate
RD had a six-fold higher in-hospital mortality rate, while
Table 4. Causes of in-hospital mortality
Estimated GFR
30-60 mL/min/1.73 m2
(n=894)
p
≥60 mL/min/1.73 m2
(n=3,515)
<30 mL/min/1.73 m2
(n=133)
Cause of hospital mortality (%)
Pump failure
Mechanical complications
Arrhythmia
Multi-organ failure
Bleeding
GFR: glomerular filtration rate
0.165
52.4
07.3
12.2
11.0
01.8
71.3
04.1
09.0
09.0
01.6
67.6
08.8
11.8
11.8
02.4
Table 5. Multivariate logistic regression analysis of predictors of in-
hospital mortality
Adjusted OR
Estimated GFR
(mL/min/1.73 m2)
≥601.00
30-602.67
<30 4.09
Age (per year)1.06
Killip class ≥32.85
LV ejection fraction0.91
Successful PCI0.39
Diabetes 2.08
Presence of left main
artery stenosis
Stent use0.60
Male gender 0.73
Hypertension1.27
Multivessel disease 0.76
Body mass index1.02
OR: odds ratio, CI: confidence interval, GFR: glomerular filtration
rate, LV: left ventricle, PCI: percutaneous coronary intervention
95% CIp
1.44-4.93
1.48-11.28
1.03-1.09
1.58-5.14
0.89-0.93
0.19-0.81
1.15-3.74
0.002
0.006
<0.001
<0.001
<0.001
0.011
0.015
2.740.86-8.75 0.090
0.22-1.61
0.39-1.36
0.70-2.30
0.38-1.53
0.94-1.11
0.310
0.318
0.427
0.449
0.650
Fig. 2. Incidence of in-hospital mortality according to the levels of
estimated glomerular filtration rate.
30
25
20
15
10
5
0
2.3
13.9
p<0.001
25.6
≥60 mL/min/
1.73 m2 (n=3,515)
<30 mL/min/
1.73 m2 (n=133)
30-60 mL/min/
1.73 m2 (n=894)

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Joon Young Kim, et al. 189
patients with severe RD had a eleven-fold higher in-hospital
mortality rate as compared to the patients with normal RF. In
our study, patients with RD were older, and were more often
women. Although RF decreases with age and women tend to
be older than men at the time of AMI presentation,24) it may
also be an inherent influence of the variables used in the MD-
RD equation. In addition to older age and female gender, RD
was more frequently associated with hypertension, diabetes,
higher Killip class, multivessel disease and low left ventricu-
lar ejection fraction. These findings which have been describ-
ed by other authors13)19)21) predispose to worse clinical out-
comes after AMI. However, after adjustment for baseline dif-
ferences, increased in-hospital mortality persisted in the pa-
tients with RD, suggesting that an increased mortality in
patients with RD was not fully explained by these associated
conditions, and that RD is a strong independent predictor of
in-hospital mortality.
The rate of in-hospital complications was higher in the pa-
tients with RD as compared to the patients with normal RF.
Cardiogenic shock, the most common cause of death in this
study regardless of RF, developed with a three-fold higher
frequency. It may be possible that the high incidence of un-
successful PCI, recurrent ischemia or re-infarction and bleed-
ing may potentiate the already existing weakened ischemic
resistance reflected by high prevalence of diabetes and multi-
vessel disease in the RD group. Also, acute renal failure devel-
oped more frequently in the RD group. After AMI, acute re-
nal failure more commonly developed among those patients
with low left ventricular ejection fraction, higher Killip class,
anterior wall infarction, a hematocrit <30%, congestive heart
failure, cardiogenic shock or stroke during admission.25) The
RD group in our study shared many of these features, and al-
though this study did not assess contrast-induced nephropa-
thy (CIN) it may also contribute to it. Usually, the clinical be-
nefit of primary PCI is accompanied by an increased risk of
bleeding in AMI patients with RD, and a previous study has
reported that RD is independently associated with bleeding
after primary PCI.19) As expected, despite the less frequent
use of heparin and glycoprotein IIb/IIIa inhibitors in the RD
group as compared to the normal RF group, which have a pro-
ven efficacy in the setting of AMI, major bleeding increased
significantly in the RD group as compared to the normal RF
group.
Despite the fact that primary PCI is the most effective AMI
treatment in terms of improvement in survival, this mortality
benefit is attenuated in some patient subgroups, including the
elderly, women, patients with renal insufficiency, heart failure,
diabetes, anaemia, acute hyperglycemia, cardiogenic shock,
and those developing CIN.15) Because the patients with RD
frequently have more than one of these conditions, they might
be at a very high risk of mortality after AMI. Therefore, man-
agement of AMI in patients with RD is particularly problema-
tic. A recent study by Medi et al.26) which investigated the be-
nefit of reperfusion strategies in STEMI patients in the
presence of RD, reported that mortality rates remain high;
they also found that primary PCI was associated with a low-
er adjusted in-hospital mortality than fibrinolytic therapy in
the patients with normal RF and moderate RD. However, in
the patients with severe RD, primary PCI was not associated
with reduced mortality. In conclusion, we have limited know-
ledge on the optimal reperfusion strategy for the severe RD
group.
To improve the survival in AMI patients with RD undergo-
ing primary PCI, more aggressive treatment and meticulous
care are needed. Firstly, the success of primary PCI has spe-
cial importance because a successful PCI is an independent
predictor of in-hospital mortality as shown in our study and
RD was shown to be associated with the risk of unsuccessful
PCI results. Secondly, medications such as aspirin, beta-bl-
ockers, and ACE inhibitors should be administered early af-
ter AMI, so that the patients with RD could gain a similar mor-
tality benefit as their normal RF counterparts.27)28) Thirdly,
reducing bleeding complications29) by using the radial artery
approach and direct thrombin inhibitor during PCI is need-
ed.30) Fourthly, an effort should be made to prevent CIN, in-
cluding adequate hydration, reducing contrast use, use of low-
osmolarity contrast and administration of N-acetylcysteine.19)20)
Because KAMIR is a large multicenter population-based
prospectively-designed study including unselected patients
with AMI, it provides comprehensive information on treat-
ments and outcomes among patients with AMI and RD in the
contemporary PCI era. Because this study included STEMI
patients only, the median pre-hospital delay time in the RD
group was relatively short as compared to that in the previous
studies13)19); this feature could minimize the hemodynamic
compromising effect of AMI on baseline serum creatinine
level.
Limitations
The present study had several limitations. Firstly, we in-
cluded only those individuals who underwent primary PCI.
Similar to a previous study, because the patients with RD un-
derwent PCI less often as compared to those with normal RF,
there might be a selection bias and unidentified confound-
ers, which might limit the generalizability of the data. Second-
ly, we did not collect information on medications relevant
for prognostication, and therefore analyses in this study was
not controlled for the impact of these drugs. Thirdly, there are
inherent limitations of the estimated GFR calculation.17)
Conclusions
Decreased estimated GFR on admission is a strong risk fac-
tor for increased in-hospital complications and mortality in ST-
EMI patients undergoing primary PCI. These risks increased

Page 7

190 Estimated GFR as a Predictor in AMI Patients Undergoing Primary PCI
in a stepwise fashion according to the degree of decreased
estimated GFR. Clinicians should be alert to the increased
mortality in patients with RD and make all the attempts to re-
duce complications of primary PCI and stress intensive medi-
cal management of these high-risk patients.
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