Heterogeneous and overlapping mechanisms of myocardial ischemia in patients with ischemia and non-obstructive coronary arteries. Preliminary results from the MOSAIC-COR Registry

Background

Patients with ischemia and non-obstructive coronary arteries (INOCA) account for 30–70% of all patients undergoing elective coronary angiography for angina. In these group of patients various mechanisms may be responsible for myocardial ischemia, including increased microvascular resistance, epicardial spasm or microvascular spasm. There are limited data on the prevalence and coexistence of different mechanisms in patients with INOCA.

Purpose

The primary objective was to assess the occurrence of coronary microcirculatory disease (CMD), epicardial vasospastic angina (EVSA), microvascular vasospastic angina (MVSA) and their coexistance in patients with INOCA. The secondary objective was the analysis of subgroups' clinical characteristics.

Methods

This was a single-center, prospective, observational study. In the absence of significant coronary artery stenosis, a complex functional coronary assessment was performed. Values of fractional flow reserve (FFR), RFR, coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) were determined. Coronary artery and microvascular vasoreactivity was tested using the provocative acetylcholine test.

Results

We enrolled 90 consecutive patients with INOCA. Overlapping of CMD and CMD/EVSA phenomenon was observed. Accordingly, we distinguished 6 subgroups of INOCA patients in comparison to the CorMicA trial. Mixed pathophysiology (CMD+EVSA and CMD+MVSA) was diagnosed in 33% of patients. In the CMD+EVSA subgroup, 73% of subjects were male, while in the CMD+MVSA only 7.1% were male (p=0.005). Typical cardiovascular risk factors were common in the whole INOCA group.

Conclusions

The INOCA population is a heterogeneous group with various pathophysiology of myocardial ischemia. Overlapping of different pathomechanisms is a frequent phenomenon, which has to be consider for treatment optimization and future research.

Funding Acknowledgement

Type of funding sources: None.

Correlations between fractional flow reserve and a novel non-hyperemic index: resting full-cycle ratio in patients with an ambiguous coronary artery stenosis

Background

Fractional flow reserve (FFR) measurement has been the gold standard for invasive assessment of coronary ischemia. Resting full cycle ratio (RFR) is a new non-hyperemic index used to define physiologic significance of coronary artery stenosis. However, there are limited data available to establish optimal cut-off value of RFR for decision making on revascularization.

Aim

The aim of our study was to assess optimal cut-off value of RFR at which to predict FFR of 0.8.

Methods

The RFR and FFR values were recorded during invasive coronary angiography in vessels with angiographic stenosis 40–70% according to visual assessment. Maximum hyperemia for FFR measurement was achieved with adenosine iv. infusion at 140 μg/kg/min. Left main disease, acute myocardial infarction and systolic left ventricular dysfunction (EF <40%) were the main exclusion criteria.

Results

We evaluated 332 vessels, including 189 (56.9%) left anterior descending arteries, 77 (23.2%) left circumflex arteries and 66 (19.9%) right coronary arteries. Median diameter stenosis as assed by QCA was 45% (IQR 40; 50). Median RFR and FFR values were 0.90 [IQR 0.85; 0.94] and 0.86 [IQR 0.81; 0.92] respectively, with significant correlation (p<0.001, Figure 1, panel A). Optimal cut-off value for RFR to detect FFR 0.80 was 0.90 with area under the curve of 90.3%, sensitivity of 81.4% and specificity 88.0% (Figure 1, panel B).

Conclusions

Our data confirm RFR cut-off value ≤0.90 as an optimal threshold to detect ischemic lesions with good sensitivity and specificity in comparison to FFR assessment. Further research is necessary to assess outcomes of RFR-guided revascularization strategy.

Figure 1. RFR–FFR correlation and ROC analysis

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Jagiellonian University statutory grant

The role of chemokine CCL5/RANTES and metalloproteinase-9 as inflammatory modulators in symptomatic internal carotid artery stenosis

Up to 80% of all ischemic strokes (IS) attributed to internal carotid athero-occlusive artery stenosis (ICAS) are related to a thromboembolic mechanism. One athero-occlusive ischemic event increases the risk for ischemia in another vascular territory, resulting from inflammation within the atherosclerotic plaque induced by cytokines. Thus, ultrasonographic characteristics of vulnerable plaques in ICAS, including plaque echolucency and ulceration might correspond to cytokine activity. The present study aimed to investigate the associations between serum cytokines and atherosclerotic plaque characteristics and the 3-year risk of a major adverse coronary and carotid ischemic event (MACCE) in symptomatic patients treated for ICAS. Plaque characteristics on ultrasonography, serum levels of C-C motif chemokine ligand 5 (CCL5)/regulated on activation, normal T-cell expressed and secreted (RANTES), metalloproteinase-9 (MMP-9), interleukin-6 (IL-6), transforming growth factor beta (TGF-β), C-X-C motif chemokine ligand 16 (CXCL16), FAS ligand (FASL) and high sensivity C-reactive protein (hs-CRP) were analyzed in 103 symptomatic patients with ICAS prior to carotid revascularization. The incidence of MACCE: cardiovascular death (CVD), myocardial infarction (MI) and recurrent ischemic stroke (IS) were recorded prospectively for up to 5 years (median 37; IQR 21 - 40 months). Echolucent plaques, in comparison to echogenic plaques, displayed lower median levels of RANTES (P = 0.042) but higher median levels of IL-6 (P = 0.039). There was no relationship between plaque characteristics and median levels of MMP-9, TGF β, CXCL16, FASL, or hs-CRP (P = NS). During follow-up, MACCE occurred in 15 (14.6%) patients. Univariate Cox proportional hazard analysis indicated median RANTES levels < 45.5ng/mL (hazard ratio (HR) = 3.95; 95%CI = 1.10 - 14.2; P = 0.035), MMP-9 > 0.6 μg/mL (HR 4.5; 95%CI = 1.4 - 13.9; P = 0.009), renal impairment (HR 3.48; 95%CI = 1.29 - 9.34; P = 0.013) as potential MACCE risk factors. On multivariate Cox proportional hazard analysis, MMP-9 > 0.6 μg/mL and RANTES < 45.5 ng/ml were associated with a 4.72-fold (95%CI = 1.3 - 17.0; P = 0.017) and a 3.8-fold risk increase (95%CI = 1.07 - 13.89; P = 0.038) of MACCE. Kaplan-Meier analysis showed significant differences in MACCE-free survival rates depending on RANTES and MMP-9 median levels. We conclude that serum RANTES, IL-6, and MMP-9 were associated with plaque vulnerability and predicted adverse MACCE in patients treated for ICAS.

Serum rantes, transforming growth factor-β1 and interleukin-6 levels correlate with cardiac muscle fibrosis in patients with aortic valve stenosis

Regulated on Activation Normal T Expressed and Secreted (RANTES) chemokine is involved in the initiation of inflammation and immune-cell recruitment. Interleukin -6 (IL-6) is used as a general index of severity of the chronic inflammatory process. Finally, transforming growth factor-β (TGF-β) is an immune biomarker potentially involved in the regulation of valve fibrosis and calcification. The aim of this study was to analyze selected biomarkers associated with the different stages of immune-pathogenesis in aortic stenosis. Forty consecutive patients with moderate to severe aortic stenosis (AS) and without previous myocardial infarction history were included in the study and divided into two groups. Two imaging techniques, echocardiography and magnetic resonance, were used to estimate the degree of AS and left ventricular muscle function. Inflammatory biomarker serum levels including CCL5/RANTES, IL-6, and TGF-β1 were determined based on ELISA measurements. Mean levels of RANTES, IL-6, and TGF-β1 did not significantly differ between both groups. A negative correlation was found between RANTES serum level and left ventricle (LV) mass as assessed by MRI (r = -0.3358, P = 0.0341). A positive correlation (r = 0.3283, P = 0.0387) was found between IL-6 serum levels and LV mass as measured by MRI. In addition, a positive correlation (r = 0.6803, P = 0.01) was seen between IL-6 serum levels and LV muscle mass with positive late gadolinium enhancement (LGE). There was a positive correlation between TGF-β1 serum level and ejection fraction as measured by echocardiography (r = 0.3217, P = 0.043). The relationship between selected inflammatory biomarkers, LV ejection fraction, LV mass, and LV muscle mass with LGE appeared to be independent of valvular pathobiologic process severity, as we did not observe differences in IL-6, RANTES, or TGF-β1 between groups differing in severity. On the contrary, these markers appear to be linked to myocardial function and remodeling, which may provide valuable insights into the pathobiology of AS and provide a basis for future detection strategies of AS.

Atrial natriuretic peptide and brain natriuretic peptide changes after epicardial percutaneous left atrial appendage suture ligation using LARIAT device

Percutaneous left atrial appendage closure is an alternative treatment for stroke and systemic thromboembolism risk reduction in non-valvular atrial fibrillation (AF). However, the neurohormonal impact of epicardial exclusion of the left atrial appendage (LAA) with the LARIAT procedure is unknown. Evaluation of changes in atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels in AF patients underwent percutaneous LAA suture ligation. Sixty six patients underwent successfully percutaneous LAA suture ligation using LARIAT device. The level of ANP and BNP was measured before and 3 months after procedure. Mean ANP level before procedure was 249 ± 77 pg/mL (range from 95 pg/mL to 503 pg/mL) and mean BNP level was 481 ± 517 pg/mL (range from 34 pg/mL to 2508 pg/mL). Three months after procedure mean ANP level was 249 ± 79 pg/mL (range from 98 pg/mL to 492 pg/mL) and mean BNP level was 495 ± 526 pg/mL (range from 52 pg/mL to 2420 pg/mL). At 3 months follow up after percutaneous LAA suture ligation there were no significant differences in ANP and BNP levels.

Chemokine RANTES is increased at early stages of coronary artery disease

Cardiovascular diseases, and in particular coronary artery disease (CAD), are the leading causes of death in Europe and represent around 50% of overall mortality. Numerous cardiovascular markers have been proposed in relation to cardiovascular risk prediction, in relation to cardiac and vascular and cerebral events. Chemokines which regulate immune cell vascular chemotaxis, including CCL5/RANTES are points of great interest. We hypothesized that chemokine RANTES level measured in peripheral blood may be associated with severity of atherosclerosis in patients with stable angina undergoing coronary angiography. RANTES and interleukin 18 (IL-18) levels were measured by ELISA. Classical and novel cardiovascular risk factors like brachial flow mediated dilation and intima-media thickness were analyzed in the context of chemokine levels and severity of atherosclerosis. Study included 62 consecutive patients with coronary atherosclerosis demonstrated by coronary angiography, (mean age 59.3 years (S.D. = 7.4)), divided into two groups: group I with lower severity of atherosclerosis, (n = 45) and group 2 with severe CAD (n = 17) based on coronary angiography. Groups were well balanced for classic risk factors for atherosclerosis. Mean RANTES level were significantly higher in patients in group I (67.9 ng/ml, S.E.M. = 3.97) than in group II (50.5 ng/ml, S.E.M. = 7.49; P = 0.03). In contrast, IL-18 levels were similar in both groups (255 pg/ml in group I and 315 pg/ml, S.E.M. = 40.91 in group I, P = 0.12), as well as hsCRP concentration (3.45 S.E.M. = 2.66 ng/ml and 4.69 ng/ml S.E.M.= 1.64 ng/ml respectively; P = 0.47). Flow-mediated dilatation (FMD) values have been significantly lower in group II than in group I (6.31; S.E.M. = 0.61; vs 4.41; S.E.M. = 0,56, respectively, P = 0.026), while nitroglycerine-mediated dilatation (NMD) did not differ, indicating more pronounced endothelial dysfunction. No significant correlations between chemokine RANTES levels and intima-media thickness (IMT), FMD measurements have been found in the total population studied. Chemokine RANTES level could become a useful marker of severity of coronary artery disease. Its lower levels were observed in patients with more diffuse disease. Elevated level of chemokine RANTES in patients with stable angina pectoris may evaluate patients to high risk group in plaque formation at early stages of atherosclerosis.