Coronary Microvascular Resistance Index Immediately After Primary Percutaneous Coronary Intervention as a Predictor of the Transmural Extent of Infarction in Patients With ST-Segment Elevation Anterior Acute Myocardial Infarction
Hironori Kitabata, MD,
Toshio Imanishi, MD, PhD,
Takashi Kubo, MD, PhD,
Shigeho Takarada, MD, PhD,
Manabu Kashiwagi, MD,
Hiroki Matsumoto, MD,
Hiroto Tsujioka, MD,
Hideyuki Ikejima, MD,
Yu Arita, MD,
Keishi Okochi, MD,
Akio Kuroi, MD,
Satoshi Ueno, MD,
Hideaki Kataiwa, MD,
Takashi Tanimoto, MD,
Takashi Yamano, MD,
Kumiko Hirata, MD, PhD,
Nobuo Nakamura, MD,
Atsushi Tanaka, MD, PhD,
Masato Mizukoshi, MD, PhD,
Takashi Akasaka, MD, PhD*
Department of Cardiovascular Medicine, Wakayama Medical University, Wakayama, Japan
* Reprint requests and correspondence: Dr. Takashi Akasaka, Department of Cardiovascular Medicine, Wakayama Medical University, 811-1 Kimiidera, Wakayama 641-8509, Japan (Email: akasat{at}wakayama-med.ac.jp).
Objectives: The purpose of this study was to investigate whether microvascular resistance index (MVRI) immediately after primary percutaneous coronary intervention (PCI) can predict the transmural extent of infarction (TEI) defined by contrast-enhanced cardiac magnetic resonance (ce-CMR) in patients with anterior acute myocardial infarction (MI).
Background: The degree of microvascular damage is an important determinant of myocardial viability and clinical outcomes in acute MI. A novel dual-sensor (pressure and Doppler velocity) guidewire has the ability to evaluate microvascular damage. ce-CMR can accurately discriminate transmural from nontransmural MI, and the TEI by ce-CMR can predict future improvement in contractile function.
Methods: In 27 patients immediately after primary PCI for a first anterior acute MI, MVRI, coronary flow reserve (CFR), deceleration time of diastolic velocity (DDT), and zero flow pressure (Pzf) were measured with a dual-sensor guidewire. TEI was graded from 1 to 4 based on the transmural extent of hyperenhanced tissue (1 = 0% to 25% of left ventricular wall thickness, 2 = 26% to 50%, 3 = 51% to 75%, and 4 = 76% to 100%). Infarct size by ce-CMR was also calculated.
Results: Peak creatine kinase-myocardial band values were significantly correlated with MVRI (r = 0.77, p < 0.0001), CFR (r = –0.69, p < 0.0001), DDT (r = –0.75, p = 0.0001), and Pzf (r = 0.75, p < 0.0001). Also, infarct size by ce-CMR was significantly correlated with MVRI (r = 0.78, p < 0.0001), CFR (r = –0.67, p < 0.0001), DDT (r = –0.70, p < 0.0001), and Pzf (r = 0.72, p = 0.0002). Receiver-operating characteristic curve analyses of MVRI, CFR, DDT, and Pzf for predicting transmural MI (TEI-grade 4) demonstrated that the area under the curve tended to be higher for MVRI (0.885) than those for CFR (0.848), DDT (0.862), and Pzf (0.853). The best cut-off value for MVRI was 3.25 mm Hg·cm–1·s (sensitivity 75%, specificity 89%). Moreover, increased MVRI was significantly related to increased TEI-grade (p < 0.0001).
Conclusions: MVRI measured immediately after primary PCI is a useful predictor for the TEI in patients with anterior acute MI.
Key Words: acute myocardial infarction • microcirculation • physiology • cardiac magnetic resonance
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Abbreviations and Acronyms
| | ce-CMR = contrast-enhanced cardiac magnetic resonance | | CFR = coronary flow reserve | | CK-MB = creatine kinase-myocardial band | | DDT = diastolic deceleration time | | FFR = fractional flow reserve | | MI = myocardial infarction | | MVRI = microvascular resistance index | | PCI = percutaneous coronary intervention | | Pzf = zero flow pressure | | TEI = transmural extent of infarction | | TIMI = Thrombolysis In Myocardial Infarction |
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