Ji-Hyun Jung

Coronary Flow Reserve and Microcirculatory Resistance in Patients With Intermediate Coronary Stenosis.

BACKGROUND The prognostic impact of microvascular status in patients with high fractional flow reserve (FFR) is not clear. OBJECTIVES The goal of this study was to investigate the implications of coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) in patients who underwent FFR measurement. METHODS Patients with high FFR (>0.80) were grouped according to CFR (≤2) and IMR (≥23 U) levels: group A, high CFR with low IMR; group B, high CFR with high IMR; group C, low CFR with low IMR; and group D, low CFR with high IMR. Patient-oriented composite outcome (POCO) of any death, myocardial infarction, and revascularization was assessed. The median follow-up was 658 days (interquartile range: 503.8 to 1,139.3 days). RESULTS A total of 313 patients (663 vessels) were assessed with FFR, CFR, and IMR. Correlation (r = 0.201; p < 0.001) and categorical agreement (kappa value = 0.178; p < 0.001) between FFR and CFR were modest. Low CFR was associated with higher POCO than high CFR (p = 0.034). There were no significant differences in clinical and angiographic characteristics among groups. Patients with high IMR with low CFR had the highest POCO (p = 0.002). Overt microvascular disease (p = 0.008), multivessel disease (p = 0.033), and diabetes mellitus (p = 0.033) were independent predictors of POCO. Inclusion of a physiological index significantly improved the discriminant function of a predictive model (relative integrated discrimination improvement 0.467 [p = 0.037]; category-free net reclassification index 0.648 [p = 0.007]). CONCLUSIONS CFR and IMR improved the risk stratification of patients with high FFR. Low CFR with high IMR was associated with poor prognosis. (Clinical, Physiological and Prognostic Implication of Microvascular Status; NCT02186093).

Comparison Among Drug-Eluting Balloon, Drug-Eluting Stent, and Plain Balloon Angioplasty for the Treatment of In-Stent Restenosis : A Network Meta-Analysis of 11 Randomized, Controlled Trials

OBJECTIVES A Bayesian network meta-analysis was performed comparing the efficacy and safety of drug-eluting balloons (DEB), drug-eluting stents (DES), or plain old balloon angioplasty (POBA) for treatment of in-stent restenosis (ISR). BACKGROUND Optimal treatment options for ISR have not been well established. METHODS Randomized, controlled trials comparing DEB, DES, and POBA for the treatment of ISR after percutaneous coronary intervention with bare metal stent or DES were included. The primary outcome was target lesion revascularization (TLR). The pairwise posterior median odds ratio (OR) with 95% credible interval (CrI) was the effect measure. RESULTS This analysis included 2,059 patients from 11 RCTs. The risk of TLR was markedly lower in patients treated with DEB (OR: 0.22, 95% CrI: 0.10 to 0.42) or DES (OR: 0.24, 95% CrI: 0.11 to 0.47) than in those treated with POBA in a random-effects model. In a comparison of DEB and DES, the risk of TLR (OR: 0.92, 95% CrI: 0.43 to 1.90) was similar. The risk of MI or all-cause mortality was lowest in the DEB group compared with the DES and POBA groups, which did not meet statistical significance. The risk of major adverse cardiac events, which was mainly driven by TLR, was also significantly lower in the DEB or and DES group (OR: 0.28, 95% CrI: 0.14 to 0.53) than in the POBA group, but it was similar between the DEB and DES groups (OR: 0.84, 95% CrI: 0.45 to 1.50). The probability of being ranked as the best treatment was 59.9% (DEB), 40.1% (DES), and 0.1% (POBA) in terms of TLR, whereas it was 63.0% (DEB), 35.3% (POBA), and 1.7% (DES) in terms of MI. CONCLUSIONS Local drug delivery by DEB or DES for ISR lesions was markedly better than POBA in preventing TLR, but not for MI or mortality. Among the 2 different strategies of drug delivery for ISR lesions, treatment with DEB showed a trend of less development of MI than did treatment with DES.

Integrated Physiologic Assessment of Ischemic Heart Disease in Real-World Practice Using Index of Microcirculatory Resistance and Fractional Flow Reserve Insights From the International Index of Microcirculatory Resistance Registry

Background—The index of microcirculatory resistance (IMR) is a quantitative and specific index for coronary microcirculation. However, the distribution and determinants of IMR have not been fully investigated in patients with ischemic heart disease (IHD). Methods and Results—Consecutive patients who underwent elective measurement of both fractional flow reserve (FFR) and IMR were enrolled from 8 centers in 5 countries. Patients with acute myocardial infarction were excluded. To adjust for the influence of collateral flow, IMR values were corrected with Yong’s formula (IMRcorr). High IMR was defined as greater than the 75th percentile in each of the major coronary arteries. FFR⩽0.80 was defined as an ischemic value. 1096 patients with 1452 coronary arteries were analyzed (mean age 61.1, male 71.2%). Mean FFR was 0.84 and median IMRcorr was 16.6 U (Q1, Q3 12.4 U, 23.0 U). There was no correlation between IMRcorr and FFR values (r=0.01, P=0.62), and the categorical agreement of FFR and IMRcorr was low (kappa value=−0.04, P=0.10). There was no correlation between IMRcorr and angiographic % diameter stenosis (r=−0.03, P=0.25). Determinants of high IMR were previous myocardial infarction (odds ratio [OR] 2.16, 95% confidence interval [CI] 1.24–3.74, P=0.01), right coronary artery (OR 2.09, 95% CI 1.54–2.84, P<0.01), female (OR 1.67, 95% CI 1.18–2.38, P<0.01), and obesity (OR 1.80, 95% CI 1.31–2.49, P<0.01). Determinants of FFR ⩽0.80 were left anterior descending coronary artery (OR 4.31, 95% CI 2.92–6.36, P<0.01), angiographic diameter stenosis ≥50% (OR 5.16, 95% CI 3.66–7.28, P<0.01), male (OR 2.15, 95% CI 1.38–3.35, P<0.01), and age (per 10 years, OR 1.21, 95% CI 1.01–1.46, P=0.04). Conclusions—IMR showed no correlation with FFR and angiographic lesion severity, and the predictors of high IMR value were different from those for ischemic FFR value. Therefore, integration of IMR into FFR measurement may provide additional insights regarding the relative contribution of macro- and microvascular disease in patients with ischemic heart disease. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT02186093.

Efficacy of Short-Term High-Dose Statin Pretreatment in Prevention of Contrast-Induced Acute Kidney Injury: Updated Study-Level Meta-Analysis of 13 Randomized Controlled Trials

Background There have been conflicting results across the trials that evaluated prophylactic efficacy of short-term high-dose statin pre-treatment for prevention of contrast-induced acute kidney injury (CIAKI) in patients undergoing coronary angiography (CAG). The aim of the study was to perform an up-to-date meta-analysis regarding the efficacy of high-dose statin pre-treatment in preventing CIAKI. Methods and Results Randomized-controlled trials comparing high-dose statin versus low-dose statin or placebo pre-treatment for prevention of CIAKI in patients undergoing CAG were included. The primary endpoint was the incidence of CIAKI within 2–5days after CAG. The relative risk (RR) with 95% CI was the effect measure. This analysis included 13 RCTs with 5,825 total patients; about half of them (n = 2,889) were pre-treated with high-dose statin (at least 40 mg of atorvastatin) before CAG, and the remainders (n = 2,936) pretreated with low-dose statin or placebo. In random-effects model, high-dose statin pre-treatment significantly reduced the incidence of CIAKI (RR 0.45, 95% CI 0.35–0.57, p<0.001, I2 = 8.2%, NNT 16), compared with low-dose statin or placebo. The benefit of high-dose statin was consistent in both comparisons with low-dose statin (RR 0.47, 95% CI 0.34–0.65, p<0.001, I2 = 28.4%, NNT 19) or placebo (RR 0.34, 95% CI 0.21–0.58, p<0.001, I2 = 0.0%, NNT 16). In addition, high-dose statin showed significant reduction of CIAKI across various subgroups of chronic kidney disease, acute coronary syndrome, and old age (≥60years), regardless of osmolality of contrast or administration of N-acetylcystein. Conclusions High-dose statin pre-treatment significantly reduced overall incidence of CIAKI in patients undergoing CAG, and emerges as an effective prophylactic measure to prevent CIAKI.

Computational fluid dynamic measures of wall shear stress are related to coronary lesion characteristics

Objective To assess the distribution of pressure and shear-related forces acting on atherosclerotic plaques and their association with lesion characteristics using coronary CT angiography (cCTA)-based computational fluid dynamics (CFD) model of epicardial coronary arteries. Methods Patient-specific models of epicardial coronary arteries were reconstructed from cCTA in 80 patients (12 women, 63.8±9.0 years). The pressure and wall shear stress (WSS) in left anterior descending coronary arteries were assessed using CFD. High-risk plaques were defined as the presence of at least one of the following adverse plaque characteristics: low-density plaque, positive remodelling, napkin-ring sign and spotty calcification. Results At resting condition, 39.5% of stenotic segments (% diameter stenosis 52.3±14.4%) were exposed to high WSS (>40 dyne/cm2). When the stenotic lesion was subdivided into three segments, the distribution of WSS was different from that of pressure change and its magnitude was highest at minimal lumen area (p<0.001). High pressure gradient, proximal location, small lumen and short length were independent determinants of WSS (all p<0.05). The plaques exposed to the highest WSS tertile had a significantly greater proportion of high-risk plaques. The addition of WSS to % diameter stenosis significantly improved the measures of discrimination and reclassification of high-risk plaques (area under the curves from 0.540 to 0.718, p=0.031; net reclassification index 0.827, p<0.001). Conclusions The cCTA-based CFD method can improve the identification of high-risk plaques and the risk stratification for coronary artery disease patients by providing non-invasive measurements of WSS affecting coronary plaques.

The efficacy and safety of mechanical hemodynamic support in patients undergoing high-risk percutaneous coronary intervention with or without cardiogenic shock: Bayesian approach network meta-analysis of 13 randomized controlled trials

BACKGROUND Studies have reported conflicting results regarding efficacy of mechanical hemodynamic support using intra-aortic balloon pump (IABP) or percutaneous ventricular assisted device (pVAD) in patients undergoing high-risk PCI. We performed a Bayesian network meta-analysis comparing the safety and efficacy of mechanical hemodynamic support devices and medical therapy (MT). METHODS AND RESULTS RCTs comparing overall mortality of IABP versus MT or IABP versus pVAD in high-risk PCI populations were included. The primary endpoint was overall mortality, using the longest available follow-up in each study. This analysis included 2843 patients from 13 trials. In network meta-analysis, overall survival benefit was not significant with IABP (RR 0.84, 95% CrI 0.56-1.24) or pVAD (RR 0.95, 95% CrI 0.42-2.06), compared with MT. IABP or pVAD also did not show early survival benefit compared with MT. In terms of bleeding, pVAD was the worst (versus IABP: RR 29.4, 95% CrI 5.99-221.0; versus MT: RR 41.7, 95% CrI 8.19-330.0), which was mainly driven by the higher incidence of bleeding in the ECMO and TandemHeart, while IABP was worse than MT (RR 1.41, 95% CrI 1.01-2.08). The incidence of acute limb ischemia or vascular complication was not different between treatment groups. CONCLUSIONS In this meta-analysis, routine elective use of IABP or pVAD did not reduce mortality, while it increased bleeding, compared with MT in high-risk PCI population or even in the patients with cardiogenic shock. Thoughtful selection of appropriate patients and balancing the risk and benefit should be the prerequisites to the use of mechanical hemodynamic support devices.

Prognostic Value of Cardiac MR Imaging for Preoperative Assessment of Patients with Severe Functional Tricuspid Regurgitation

Purpose To explore the prognostic value of cardiac magnetic resonance (MR) imaging in predicting postoperative cardiac death in patients with severe functional tricuspid regurgitation (TR). Materials and Methods This study was approved by the institutional review board, and written informed consent was obtained from all patients. Prospectively collected data included cardiac MR images, New York Heart Association (NYHA) functional class, a comprehensive laboratory test, and clinical events over the follow-up period in 75 consecutive patients (61 women and 14 men; mean age ± standard deviation, 59 years ± 9) undergoing corrective surgery for severe functional TR. Cox proportional hazards models were used to assess the association between cardiac MR parameters and outcomes. Results During a median follow-up period of 57 months (range, 21-82 months), cardiac mortality and all-cause mortality were 17.3% and 26.7%, respectively, with a surgical mortality of 6.7%. Cardiac death risk was lower with a higher right ventricular (RV) ejection fraction (EF) on cardiac MR images (hazard ratio per 5% higher EF = 0.790, P = .048). By adjusting for confounding variables, RV EF remained a significant predictor for cardiac death (P < .05) and major postoperative cardiac events (P < .05). The area under the receiver operating characteristic curve (AUC) confirmed the incremental role of RV EF on cardiac MR images in the prediction of postoperative cardiac death (AUC, 0.681-0.771; P = .041) and major postoperative cardiac events (AUC, 0.660-0.745; P = .044) on top of NYHA class. RV end-systolic volume index was also independently associated with these outcomes but failed to increase the AUC significantly. Conclusion Preoperative assessment of cardiac MR imaging-based RV EF provides independent and incremental prognostic information in patients undergoing corrective surgery for severe functional TR. (©) RSNA, 2016 Online supplemental material is available for this article.

Three-Vessel Assessment of Coronary Microvascular Dysfunction in Patients With Clinical Suspicion of Ischemia: Prospective Observational Study With the Index of Microcirculatory Resistance

Background— Difficulty directly visualizing the coronary microvasculature as opposed to the epicardial coronary artery makes its assessment challenging. The goal of this study is to measure the index of microcirculatory resistance (IMR) in all 3 major coronary vessels to identify the clinical and angiographic predictors of an abnormal IMR. Methods and Results— Ninety-three patients who underwent coronary physiological assessment in all 3 major coronary vessels were prospectively enrolled (59.8±9.4 years with 77.4% men). IMR was corrected using Yong’s formula and coronary microvascular dysfunction (CMD) was defined using vessel-specific cutoffs. A global IMR was calculated as the sum of the IMR in all 3 major epicardial vessels. Angiographic epicardial disease severity was assessed with vessel-specific and overall SYNTAX score. Median IMR and fractional flow reserve was 17.2 (Q1–Q3: 13.3–22.9) and 0.92 (0.85–0.97). The majority of patients (59.1%) had no CMD, 23.7% had 1-vessel CMD, 14.0% had 2-vessel CMD, and 3.2% had 3-vessel CMD. CMD was observed at a similar rate in the territories supplied by all 3 major coronary vessels (left anterior descending coronary artery 28.0%, left circumflex artery 19.4%, and right coronary artery 23.7%; P=0.39). Fractional flow reserve had a weak, positive correlation with IMR (&rgr;=0.16; P<0.01). The SYNTAX score had no significant correlation with IMR, both at a patient level (&rgr;=−0.002; P=0.99) and a vessel-specific level (&rgr;=−0.06; P=0.36). By multivariable ordinal logistic regression analysis, no variable was left as an independent predictor of an abnormal IMR. Conclusions— Clinical factors and epicardial coronary disease severity are not predictors of the extent of CMD. Clinical Trial Registration— URL: https://www.clinicaltrials.gov. Unique identifier: NCT01621438.

Response by Kobayashi et al to Letter Regarding Article, “Three-Vessel Assessment of Coronary Microvascular Dysfunction in Patients with Clinical Suspicion of Ischemia: Prospective Observation Study With the Index of Microcirculatory Resistance”

We thank Dr. Smilowitz for his interest in our study.1 In previous studies examining the invasive assessment of the coronary microvasculature, the left anterior descending artery was selected for practical purposes, either because it was the culprit vessel in an acute coronary syndrome or because the anterior wall was felt to be the most important territory.2 As shown in the present study, we do not advocate interrogating only the left anterior descending artery because coronary microvascular dysfunction may occur in …

TCT-522 The Independence of Coronary Microvascular Dysfunction from Epicardial Disease Severity: Three-Vessel Invasive Coronary Physiologic Study

The index of microcirculatory resistance (IMR) is an invasive measure of the coronary microvascular function. To date, little is known about the collinearity in disease progression between microvascular and epicardial coronary artery. This study consisted of 93 patients who underwent three-vessel