Clinical Investigations Impact of Lesion Length on Functional Significance in Intermediate Coronary Lesions
Address for correspondence: Tomokazu Iguchi, MD Department of Internal Medicine and Cardiology Osaka City University 1-4-3 Asahi-machi, Abeno-ku Osaka 545-8585, Japan
[email protected]
Tomokazu Iguchi, MD; Takao Hasegawa, MD; Satoshi Nishimura, MD, PhD; Shinji Nakata, MD, PhD; Toru Kataoka, MD, PhD; Shoichi Ehara, MD, PhD; Akihisa Hanatani, MD, PhD; Kenei Shimada, MD, PhD; Minoru Yoshiyama, MD, PhD Department of Internal Medicine and Cardiology, Graduate School of Medicine, Osaka City University, Osaka, Japan
Background: Myocardial fractional flow reserve (FFR) is useful in the evaluation of coronary lesion ischemia. However, the impact of lesion length on FFR has not been adequately assessed. Hypothesis: We hypothesized that lesion length would influence functional significance in intermediate coronary lesions. Methods: FFR measurements were assessed in 136 patients (163 lesions) with stable angina who had >40% stenotic coronary lesion by quantitative coronary angiography (QCA). One hundred sixty-three lesions were classified as intermediate (40%–70% stenosis; n=107; group I) or significant (≥70%; n=56; group S) by QCA. We assessed the relationships between lesion length, coronary stenosis, and FFR in these 163 lesions. Results: Regression analysis revealed an inverse correlation between the percentage of diameter stenosis (%DS) and FFR in group S (r = −0.83, P < 0.0001). In group I, no significant correlation was found between %DS and FFR (r = −0.06, P = 0.55), whereas lesion length was significantly inversely correlated with FFR (r = −0.79, P < 0.0001). Receiver operating characteristic curve analysis demonstrated that the best cutoff value for predicting an FFR value 16.1 mm in group I (sensitivity, 86%; specificity, 94%). Conclusions: These study findings suggest that lesion length has a physiologically significant impact on intermediate-grade coronary lesions.
Introduction Coronary lesion severity can be assessed using both anatomical (morphology) and physiological myocardial ischemia methods. Although coronary angiography (CAG) is the conventional gold standard anatomical evaluation method, intravascular ultrasound (IVUS) has markedly improved evaluation accuracy.1 – 3 Optical coherence tomography, which can provide a detailed evaluation of the plaque nature, has also been developed.4,5 Although physiological assessment, including stress electrocardiogram, echocardiography, and single-photon emission computed tomography (SPECT) cannot be performed simultaneously with anatomical assessment, the assessment of physiological indicators by fractional myocardial flow reserve (FFR) using a pressure wire in recent years has allowed simultaneous evaluation with CAG. An FFR value 90%.6,7 The recent remarkable development of multidetectorrow computed tomography has facilitated noninvasive assessments in outpatients with coronary artery disease (CAD), but techniques for the physiological assessment of ischemia (such as SPECT) are not often performed when patients undergo invasive CAG. FFR has been
The authors have no funding, financial relationships, or conflicts of interest to disclose.
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Clin. Cardiol. 36, 3, 172–177 (2013) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI:10.1002/clc.22076 © 2012 Wiley Periodicals, Inc.
used to assess revascularization indications. Several studies have suggested that, compared with angiography-guided percutaneous coronary intervention (PCI), FFR-guided PCI is associated with reduced major adverse cardiac events in patients with multivessel CAD.8 – 11 Although it is recommended that myocardial ischemia in CAD be determined using both physiological and morphological evaluation methods,12,13 it is often assessed visually from CAG findings in daily clinical practice. However, visual estimation of coronary lesions is inaccurate.14 – 16 Results obtained from quantitative coronary analysis (QCA) are often misread compared to those obtained from other modalities with regard to functional myocardial ischemia, particularly intermediate coronary lesions (40%–70% stenosis).15,17 Although lesion length is an important geometric parameter in addition to the degree of lesion stenosis in the morphological assessment of coronary ischemia, the impact of lesion length on FFR has never been adequately assessed. The purpose of this study was to investigate the relationships between FFR and lesion length, or coronary stenosis.
Methods Study Population The study population comprised 165 consecutive patients (199 lesions) with CAD who had at least 1 de novo lesion Received: August 17, 2012 Accepted with revision: October 5, 2012
Table 1. Patient and Lesion Characteristics Total N=163
Group I n=107
Group S n=56
P Value (I vs S)
Age, y
69.0 ± 9.1
69.0 ± 9.4
68.8 ± 8.6
0.90
Men, n (%)
126 (77.3)
83 (77.6)
43 (76.8)
0.91
Body mass index
23.7 ± 3.5
23.3 ± 3.5
24.3 ± 3.6
0.09
Hypertension, n (%)
124 (76.1)
80 (74.8)
44 (78.6)
0.59
Diabetes, n (%)
99 (60.7)
62 (57.9)
37 (66.1)
0.31
Dyslipidemia, n (%)
99 (60.7)
64 (59.8)
35 (62.5)
0.74
Current smoker, n (%)
78 (47.9)
51 (47.7)
27 (48.2)
0.95
Family history, n (%)
31 (19.0)
20 (18.7)
11 (19.6)
0.88
CKD, n (%)
29 (17.8)
19 (17.8)
10 (17.9)
0.99
Previous PCI, n (%)
51 (31.3)
36 (33.6)
15 (26.8)
0.37
56.5 ± 7.5
56.4 ± 7.4
56.7 ± 7.6
0.77
LVEF, % Target vessel, n (%)
0.66
LAD
95 (58.3)
64 (60.8)
31 (55.4)
LCx
33 (20.3)
20 (18.7)
13 (23.2)
RCA
33 (20.3)
21 (19.6)
12 (21.4)
2 (1.2)
2 (1.9)
0 (0)
66 (40.5)
47 (43.9)
19 (33.9)
LMCA ACC/AHA classification B2+C, n (%)
0.22
QCA and FFR Proximal RD (mm)
2.89 ± 0.67 2.92 ± 0.70 2.83 ± 0.60
0.39
Distal RD (mm)
2.62 ± 0.65 2.57 ± 0.67 2.70 ± 0.62
0.25
RD (mm)
2.85 ± 2.52 2.91 ± 3.08 2.73 ± 0.60
0.68
MLD (mm)
1.00 ± 0.43 1.24 ± 0.30 0.55 ± 0.25
