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Coronary flow reserve (CFR) represents entire coronary compensatory capacity, while fractional flow reserve (FFR) is a standard to evaluate functional severity of epicardial coronary artery disease (CAD). ΔFFR, a decrease in a ratio of mean distal coronary pressure to aortic pressure (Pd/Pa) at rest to FFR, is conceptually associated with coronary microvascular function. This study aimed to evaluate the relation of ΔFFR to CFR in patients with stable CAD.We performed resting Pd/Pa and FFR measurements in a total of 309 vessels with intermediate coronary artery stenosis in 242 patients. ΔFFR was defined as (resting Pd/Pa - FFR), and pressure bounded-CFR was calculated to estimate low CFR. Vessels were divided as the low CFR and non-low CFR groups.Of 309 vessels, low CFR was observed in 101 (32.7 %). While FFR values were similar (0.78 ± 0.11 vs. 0.78 ± 0.09, p = 0.84), resting Pd/Pa (0.85 ± 0.08 vs. 0.93 ± 0.04, p 0.001) and ΔFFR (0.07 ± 0.06 vs. 0.15 ± 0.06, p 0.001) were significantly lower in the low CFR group than in the non-low CFR group. The receiver operating characteristic curve analysis indicated that ΔFFR was predictive for low CFR (area under the curve 0.84, best cut-off value 0.08, p 0.001). Multivariable analysis identified lower ΔFFR, the left anterior descending coronary artery, and lower hemoglobin and higher brain natriuretic peptide levels as factors associated with low CFR.In patients with stable CAD, lower ΔFFR was significantly associated with low CFR in intermediate coronary stenosis in patients with stable CAD. ΔFFR may be a simple, practical, and useful surrogate to identify patients with impaired CFR.

Resting full-cycle ratio (RFR), a non-hyperemic pressure ratio, is alternative to fractional flow reserve (FFR) for the evaluation of coronary artery stenoses. Although FFR and RFR results are often discordant using the cut-off values (0.80 and 0.89), factors associated with the discordance are unclear. The aim of this study was to explore factors related to the discordant results.We performed FFR and RFR measurements in a total of 408 vessels with intermediate coronary artery stenosis in 277 patients. Positive FFR and RFR were defined based on the cut-off values of 0.80 and 0.89. The discordance was determined as positive FFR and negative RFR (FFR ≤0.80 and RFR0.89) or negative FFR and positive RFR (FFR0.80 and RFR ≤0.89).Overall, FFR and RFR were significantly correlated (r = 0.76, p 0.001), while positive FFR and negative RFR and negative FFR and positive RFR were observed in 44 (10.8%) and 45 (11.0%) of 408 vessels, respectively. Smaller body surface area, diabetes, chronic kidney disease including hemodialysis, severe aortic stenosis, higher E/e', and lower left ventricular ejection fraction on echocardiography, and lower hemoglobin and higher brain natriuretic peptide levels were identified as factors associated with the negative FFR and positive RFR discordance.Discordant results between FFR and RFR were often found in more than 20% of vessels with intermediate coronary stenosis. Clinical characteristics such as renal function, heart failure, and anemia may be considered in clinical decision-making when using FFR and RFR.

Uric acid, the end-product of purine metabolism in humans, is not only a cause of gout, but also may play roles in developing cardiovascular diseases such as hypertension, atrial fibrillation, chronic kidney disease, heart failure, coronary artery disease, and cardiovascular death. Several clinical investigations have reported serum uric acid as a predictive marker for cardiovascular outcomes. Although the causal relationship of hyperuricemia to cardiovascular diseases remains controversial, there has been a growing interest in uric acid because of the increased prevalence of hyperuricemia worldwide. This review article summarizes current evidence concerning the relation between hyperuricemia and cardiovascular diseases.

Owing to recent advances in early reperfusion strategies, pharmacological therapy, standardized care, and the identification of vulnerable patient subsets, the prognosis of acute myocardial infarction has improved. However, there is still considerable room for improvement. This review article summarizes the latest evidence concerning clinical diagnosis and treatment of acute myocardial infarction.

In acute myocardial infarction (MI), the prognosis has been improved, and the length of hospital stay has been shortened. In the present study, we aimed to evaluate the potential of identifying low-risk patients for early discharge after acute MI using the GRACE and CADILLAC risk scores.This bi-center registry included 797 patients with acute MI undergoing primary percutaneous coronary intervention. Patients were divided into 3 groups according to the tertiles and pre-defined thresholds of the GRACE and CADILLAC scores. The primary endpoint was a composite of in-hospital major adverse events (all-cause death, sustained ventricular arrhythmia, recurrent MI, heart failure requiring intravenous treatment, stroke, and major bleeding events).Of 797 patients, 271 (34.0%) and 316 (39.7%) had low GRACE and CADILLAC risk scores. During the hospitalization, 251 (31.5%) patients had major adverse events. Higher GRACE and CADILLAC scores were associated with longer length of stay and higher in-hospital adverse event rates. In patients with low GRACE and/or CADILLAC risk scores, 16 (5.9%) and 16 (5.1%) had in-hospital adverse events, most of which occurred within 3 days. Only 1 (0.4% and 0.3%) patient had major adverse events on day 4 or later in the low GRACE and CADILLAC risk score groups.In patients with acute MI with low GRACE and/or CADILLAC risk scores who were free from acute events within 3 days, early discharge after primary percutaneous coronary intervention may be feasible and safe.

Background Previous studies have reported that glucose variability leads to endothelial dysfunction and progression of coronary atherosclerosis. However, few studies have directly evaluated the relation between glucose variability and coronary endothelial function in patients with coronary artery disease (CAD). Methods A total of 38 patients with chronic CAD and a history of coronary drug-eluting stent implantation were enroled. Coronary endothelial function was evaluated by measuring the coronary vasoreactivity using quantitative coronary angiography in the segment distal to implanted stent in response to intracoronary acetylcholine (ACh) infusion (10−7 mol/l). Peripheral endothelial function was also assessed with reactive hyperemia index (RHI). The mean amplitude of glycemic excursion (MAGE) was calculated as a primary metric of glucose variability using a flash glucose monitoring system. Results Of 38 patients, 17 (45%) had diabetes mellitus. The mean levels of glycated hemoglobin, MAGE, and RHI were 6.3 ± 0.8%, 71.4 ± 29.8 mg/dl, and 1.85 ± 0.63. In the distal segment to coronary stent, lumen diameter was constricted by 0.6 ± 7.3% in response to intracoronary ACh infusion compared to that at baseline. While peripheral endothelial function assessed with RHI was not significantly associated with MAGE (r = −0.16, p = 0.35), coronary endothelial function was correlated with MAGE (r = −0.38, p = 0.02). Conclusion Greater glucose variability was significantly associated with coronary rather than peripheral endothelial dysfunction in patients with CAD, suggesting an impact of glucose variability on coronary atherosclerosis. Endothelial function; Coronary artery disease; Acetylcholine; Glucose variability

Background Recent guidelines recommend risk stratification using objective scoring systems in patients with acute coronary syndrome. In this context, the CADILLAC (Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications) and GRACE (Global Registry of Acute Coronary Events) risk scores were both originally established to predict short-term mortality. However, their impact on short- and long-term clinical outcomes in a contemporary cohort of patients with acute myocardial infarction (MI) is unclear. Methods This bi-center registry included 809 patients with acute MI undergoing primary percutaneous coronary intervention. Patients were divided into three groups according to the pre-defined thresholds and tertiles of the CADILLAC and GRACE scores. The study endpoints included all-cause death and major adverse cardiovascular events (MACE) during the index hospitalization and after discharge. Results Of 809 patients, 323 (39.9%) and 255 (31.5%) had high CADILLAC and GRACE risk scores. During the index hospitalization, 61 (7.5%) patients died and 262 (32.4%) had MACE. Both CADILLAC and GRACE risk scores were associated with in-hospital mortality and MACE rates. After discharge, out of 683 patients with available follow-up information who survived to discharge, 42 (6.1%) died and 123 (18.0%) had MACE during the median follow-up period of 632 days. Significantly higher incidence of MACE in higher CADILLAC and GRACE risk scores was observed in a stepwise manner. Conclusion Both CADILLAC and GRACE risk scores were predictive for short- and long-term mortality and MACE rates in a contemporary cohort of acute MI patients undergoing primary percutaneous coronary intervention.

Ticagrelor and prasugrel are novel and potent P2Y12 inhibitors. Ticagrelor 90mg or 60mg twice daily is known to reduce ischemic events but be associated with an increased risk of bleeding in patients with prior myocardial infarction in Western countries. Although ticagrelor 90mg twice daily was tested in a randomized clinical trial in East Asia, the clinical significance of ticagrelor 60mg twice daily is unclear. This study aimed to evaluate platelet inhibition of low-dose ticagrelor compared to prasugrel in Japanese patients.A total of 33 patients with prior myocardial infarction (3 months) who received aspirin and prasugrel 3.75mg once daily were enrolled. Prasugrel was switched to ticagrelor 60mg twice daily. Platelet inhibition was assessed by VerifyNow assay (Accumetrics, San Diego, CA, USA) at baseline and 14 days after switching to ticagrelor. P2Y12 reaction unit (PRU) ≤95 was defined as low on-treatment platelet reactivity (LPR) and PRU≥262 as high on-treatment platelet reactivity.Ticagrelor treatment resulted in significantly lower PRU [10 (7-39) vs. 143 (102-201), p0.001] and a higher rate of LPR (94% vs. 24%, p0.001), compared to prasugrel treatment. Neither patients treated with ticagrelor nor prasugrel had high on-treatment platelet reactivity. During 2-week follow-up on ticagrelor therapy, no major bleeding occurred in both groups, while four minor bleeding events were observed.In Japanese patients with prior myocardial infarction, significantly lower PRU and a higher rate of LPR were observed on ticagrelor 60mg twice daily compared to prasugrel 3.75mg once daily.

Approximately 50% of patients with acute myocardial infarction including ST segment elevation myocardial infarction and non-ST segment elevation myocardial infarction have multivessel (MV) coronary artery disease. Recently, the evidence for beneficial outcomes associated with MV percutaneous coronary intervention (PCI) compared with culprit-only PCI has increased. However, optimal timing of non-culprit revascularization, appropriate lesion assessment in non-culprit vessels, and the best treatment strategy for patients with cardiogenic shock remain unclear. This review summarizes current evidence and focuses on the PCI strategies in patients with acute myocardial infarction and MV disease.

Background Prevalence of myocardial bridging of the left anterior descending coronary artery (LAD) in patients with takotsubo syndrome (TTS) has been demonstrated. However, the impact of myocardial bridging on in-hospital outcome has not been fully evaluated. Methods A total of 144 consecutive patients with TTS were enrolled. Coronary angiography and left ventriculography were performed in all patients and absence of obstructive coronary disease explaining the left ventricular contraction abnormality was confirmed. Myocardial bridging was diagnosed when a dynamic compression in systole, so-called “milking effect”, was observed in the LAD. We evaluated differences in the clinical characteristics and in-hospital outcome between patients with and without myocardial bridging. Furthermore, multiple logistic regression analysis was performed to predict in-hospital death. Results Myocardial bridging was observed in 33 patients (23%). In-hospital death was more frequent in patients with myocardial bridging (21% vs. 6%, p = 0.02), which was due mainly to a higher non-cardiac death in those patients (15% vs. 5%, p = 0.049). Multiple logistic regression analysis demonstrated myocardial bridging (odds ratio = 12.0, 95% CI = 2.52–78.5, p Conclusion Myocardial bridging is an independent predictor of in-hospital death in patients with TTS.