Residual functional SYNTAX score by quantitative flow ratio and improvement of exercise capacity after revascularization in patients with stable ischemic heart disease

Background

In patients with stable ischemic heart disease (SIHD), the efficacy of percutaneous coronary intervention (PCI) in improving exercise capacity has been under debate and the differential effect of PCI for exercise capacity, according to functional completeness of revascularization, has not been evaluated.

Purpose

This study aimed to evaluate the association between improvement in exercise capacity and functional completeness of revascularization, determined by residual functional SYNTAX score (rFSS), which is the sum of residual SYNTAX score of the vessels with post-PCI quantitative flow ratio (QFR)≤0.80.

Methods

Among patients enrolled in the QFR multicenter registry, 110 patients who underwent prespecified routine exercise treadmill tests before and after PCI were analyzed. Patients were classified into functional complete revascularization (CR) group (rFSS=0) and functional incomplete revascularization (IR) group (rFSS≥1). Increase of exercise time after PCI was compared between the 2 groups. Improvement of exercise capacity was defined as ≥10% increase of exercise time after PCI.

Results

Functional CR was achieved in 79 patients (71.8%), otherwise classified as functional IR in 31 patients (18.2%). There were no significant differences in baseline characteristics including medication profiles. Increase of exercise time was significantly associated with increase of 3-vessel QFR (r=0.198, P=0.038) and rFSS (r=−0.312, P<0.001), but not with decrease of SYNTAX score (r=0.097, P=0.313). The rFSS showed significantly higher c-index to predict the improvement of exercise capacity after PCI than increase of 3-vessel QFR or decrease of SYNTAX score (0.722 vs. 0.627 vs. 0.492, respectively, P<0.001). Patients with functional CR, defined by rFSS, showed significantly higher increase of exercise time than those with functional IR (97.7 sec vs. 12.5 sec, P<0.001). Functional CR was an independent predictor of the improvement of exercise capacity after PCI (adjusted odds ratio 4.656, 95% CI 1.678–12.920, P=0.002).

Conclusions

Integrated anatomic and functional scoring system (rFSS) was significantly associated with improvement of exercise capacity after PCI. SIHD patients with functional CR, defined by rFSS, showed significantly higher exercise capacity after PCI than those with functional IR.

Summarizing Figure

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): SaeHan NK & D and Medis Corporation

Correlation of coronary microvascular function and diastolic dysfunction

Background

Coronary microvascular dysfunction (CMD) is an important mechanism for heart failure with preserved ejection fraction (HFpEF) which is closely related with diastolic dysfunction on transthoracic echocardiography (TTE).

Purpose

The aim of this study was to evaluate the association of CMD with echocardiographic parameters of diastolic dysfunction.

Methods

Total 385 patients with chest discomfort in the absence of significant coronary artery obstruction were enrolled to this study and underwent invasive coronary physiologic assessment including index of microcirculatory resistance (IMR), and coronary flow reserve (CFR). Echocardiographic parameters for diastolic dysfunction - left atrial volume index (LAVI) and left ventricular filling pressure (E over e') were compared in patients with true CMD (CFR<2.5 with IMR ≥20), mismatched CMD (CFR≥2.5 with IMR ≥20 or CFR<2.5 with IMR <20), and no CMD (CFR≥2.5 with IMR <20).

Results

Among the study population, 55 patients (14.3%) were true CMD, 162 patients (42.1%) were mismatched CMD and 168 patients (43.6%) were no CMD. Age (62.9±10.5 vs. 61.1±9.9 vs. 61.7±10.5, p=0.522) and left ventricular ejection fraction (63.9±8.1 vs. 63.9±6.2 vs. 63.0±6.7, p=0.414) was not different between groups. Patients with true CMD showed significantly larger left atrial size (LAVI: 34.7±18.2 mL/m2 vs. 26.8±10.7 mL/m2, p=0.005) and trend towards higher LV filling pressure (E/e': 10.8±3.5 vs. 9.9±3.5, p=0.073) compared with no CMD. In subgroup analysis, younger patients showed more pronounced increase of LAVI (Age <65: 39.6±22.6 vs. 26.1±11.6, p=0.003; Age ≥65: 28.0±9.13 vs. 28.8±8.2, p=0.266; p for interaction 0.043) in true CMD compared to no CMD. Non-diabetic patients also showed more pronounced increase of E/e' in true CMD (Non-diabetes: 10.2±2.7 vs. 9.2±2.6, p=0.002; Diabetes: 12.1±4.5 vs. 11.9±5.1, p=0.197; p for interaction 0.015).

Conclusions

Coronary microvascular dysfunction is significantly related with echocardiographic parameters of diastolic dysfunction. The effect of CMD on diastolic dysfunction is more prominent in low-risk patients.

Figure 1

Funding Acknowledgement

Type of funding source: None

Coronary circulatory indices in non-infarct related vascular territories in a porcine acute myocardial infarction model

Background

There has been debate on the reliability of fractional flow reserve (FFR) or resting pressure-derived indices in non-IRA of patients with acute ST-segment elevation myocardial infarction.

Purpose

This study aimed to evaluate temporal changes of coronary hemodynamic and physiologic indices in non-infarct related artery (non-IRA), which might be affected by adjacent infarcted myocardium, using an experimental animal model of acute myocardial infarction (AMI).

Methods

In Yorkshire swine, acute myocardial infarction was simulated with selective balloon occlusion at left circumflex artery (LCX) as IRA for 30 minutes. Non-IRA stenosis was created using bare metal stent implantation in left anterior descending artery (LAD) 4 weeks before the experiments. Serial changes of systemic hemodynamics, coronary pressure, and Doppler-derived coronary flow velocity were measured in a non-occluded LAD as non-IRA from baseline, balloon occlusion of LCX, and 15 minutes after reperfusion of LCX.

Results

Among the 6 experimental subjects, the median diameter stenosis of non-IRA was 33.9% (Q1-Q3: 21.7%-46.1%). During balloon occlusion of IRA, there were transient significant changes in both resting and hyperemic aortic pressure (Pa), distal coronary pressure (Pd), averaged peak velocity (APV), trans-stenotic pressure gradient (PG), and microvascular resistance of non-IRA (all P values<0.020). After reperfusion of IRA, the resting APV (P=0.002) and resting trans-stenotic PG (P=0.004) were significantly increased and resting microvascular resistance (P=0.004) was significantly decreased than those in baseline phase. However, the hyperemic APV (P=0.479), hyperemic trans-stenotic PG (P=0.778), and hyperemic microvascular resistance (P=0.816) were not significantly different compared with those in the baseline phase. After reperfusion, the FFR in non-IRA was not significantly different (0.94±0.01 vs. 0.93±0.01, P=0.353), while the CFR (1.93±0.07 vs. 1.36±0.07, P=0.025) and resting Pd/Pa (0.98±0.01 vs. 0.94±0.01, P=0.017) were significantly lower than baseline values.

Conclusions

In a porcine AMI model, occlusion of IRA induced significant changes of systemic hemodynamics and coronary circulatory indices of non-IRA. However, after reperfusion of IRA, FFR did not change significantly, while resting

Summarizing Figure

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): 1. Philips/Volcano, 2. Bio & Medical Technology Development Program of the National Research Foundation of the Korean government

Etoposide induces G2/M arrest and apoptosis in neural progenitor cells via DNA damage and an ATM/p53-related pathway

Etoposide (VP-16), an anti-tumor agent, is a topoisomerase II inhibitor that causes DNA damage. In our previous studies, it was shown that VP-16 induces S-phase accumulation and G2/M arrest, eventually resulting in apoptosis, through p53-related pathway in the mouse fetal brain. We injected 4 mg/kg of VP-16 into pregnant mice on day 12 of gestation, and the fetuses were investigated for the cell cycle checkpoint and mechanism of apoptosis. The transition of the neural progenitor cells in the fetuses was delayed as compared to that in the control, and most of the apoptotic cells were BrdU positive. VP-16-induced S-phase accumulation was brought about by the acceleration of G1/S transition rather than by the inhibition of S-phase progression. Phosphorylation of ataxia telangiectasia-mutated kinase (ATM) at Ser1981 and gammaH2AX after VP-16 treatment showed DNA damage. p53 was phosphorylated at Ser15 and 20 and increased after activation of the ATM kinase pathway. Cdc25A degradation might induce the inhibition of S-phase progression. It is supposed that an increase in cyclin A might accelerate G1/S progression. It is also indicated that VP-16-induced G2/M arrest is caused by p21, which inactivates cyclin B-Cdc2 complex and eventually prevents mitotic entry. In p53-deficient fetal brains, G2/M and apoptosis were almost abrogated, although S-phase accumulation still occurred. It is suggested that VP-16 induced p53-independent S-phase accumulation, and p53-dependent G2/M arrest and apoptosis of the neural progenitor cells in fetal mouse brain.

Histopathological changes in the brain of mouse fetuses by etoposide-administration

Etoposide (VP-16), a topoisomerase II inhibitor, is an anti-tumor agent which is also known to show embryotoxicity, and teratogenicity when administered to pregnant rodents. We examined VP-16-induced histopathological changes in the brain of mouse fetuses. Pregnant mice were intraperitoneally injected with VP-16 (4 mg/kg) on day 12 of gestation (GD 12), and fetuses were collected from 1 to 48 hours after treatment (HAT). Mitotic neuroepithelial cells in the telencephalic wall prominently decreased at 2 HAT, and were hardly observed at 4 HAT. The number of pyknotic neuroepithelial cells in the fetal brain began to increase at 4 HAT, and became prominent from 8 to 24 HAT. These pyknotic cells were also positively stained by TUNEL method, which can detect fragmented DNA, and showed ultrastructural characteristics of apoptosis. Additionally, these cells were also positive for cleaved caspase-3, an essential executioner of apoptosis. This indicated that excessive neuroepithelial cell apoptosis was induced in the brain of mouse fetuses following VP-16 treatment on GD 12.

Anti-acne effects of Oriental herb extracts: a novel screening method to select anti-acne agents

The acne-therapeutic effects of Oriental herb extracts were investigated in terms of antichemotactic effect on polymorphonuclear leucocytes, antilipogenic actions, antibacterial activity against Propionibacterium acnes and resistance induction potency in the bacteria. The ethanol extract (0.01%) of Angelica dahurica markedly suppressed neutrophil chemotaxis, comparable to the effect of erythromycin (0.01%), whereas a strong antilipogenic effect was obtained with rhizoma coptidis (Coptis chinensis) extract (0.01%), leading to a higher efficacy than that of retinoic acid (0.01%). Interestingly, only Glycyrrhiza glabra showed a remarkable antibacterial activity against P. acnes, resulting in negligible induction of resistance, in comparison with a marked development of resistance in the bacteria treated with erythromycin. We suggest that an appropriate formulation containing A. dahurica, rhizoma coptidis and G. glabra could be helpful for the prevention and treatment of acne lesions.