Factors Associated with Impaired Resistive Reserve Ratio and Microvascular Resistance Reserve

Factors Contributing to Coronary Microvascular Dysfunction in Patients with Angina and Non-Obstructive Coronary Artery Disease

BACKGROUND

Coronary microvascular dysfunction (CMD), characterised by a reduced coronary flow reserve (CFR) or an increased index of microcirculatory resistance (IMR), has received considerable attention as a cause of chest pain in recent years. However, the risks and causes of CMD remain unclear; therefore, effective treatment strategies have not yet been established. Heart failure or coronary artery disease (CAD) is a risk factor for CMD, with a higher prevalence among women. However, the other contributing factors remain unclear. In this study, we assessed the risk in patients with angina and non-obstructive coronary artery disease (ANOCA), excluding those with heart failure or organic stenosis of the coronary arteries. Furthermore, we analysed whether the risk of CMD differed according to component factors and sex.

METHODS

This study included 84 patients with ANOCA (36 men and 48 women; mean age, 63 years) who underwent coronary angiography and functional testing (CFT). The CFT included a spasm provocation test (SPT), followed by a coronary microvascular function test (CMVF). In the SPT, patients were mainly provoked by acetylcholine (ACh), and coronary spasm was defined as >90% transient coronary artery constriction on coronary angiography, accompanied by chest pain or ischaemic changes on electrocardiography. In 15 patients (18%) with negative ACh provocation, ergonovine maleate (EM) was administered as an additional provocative drug. In the CMVF, a pressure wire was inserted into the left anterior descending coronary artery using intravenous adenosine triphosphate, and the CFR and IMR were measured using previously described methods. A CFR < 2.0 or IMR ≥ 25 was indicative of CMD. The correlations between various laboratory indices and CMD and its components were investigated, and logistic regression analysis was performed, focusing on factors where p < 0.05.

RESULTS

Of the 84 patients, a CFR < 2.0 was found in 22 (26%) and an IMR ≥ 25 in 40 (48%) patients, with CMD identified in 46 (55%) patients. CMD was correlated with smoking (p = 0.020) and the use of EM (p = 0.020). The factors that correlated with a CFR < 2.0 included the echocardiograph index E/e' (p = 0.013), which showed a weak but positive correlation with the CFR (r = 0.268, p = 0.013). Conversely, the factors correlated with an IMR ≥ 25 included RAS inhibitor usage (p = 0.018) and smoking (p = 0.042). Assessment of the risk of CMD according to sex revealed that smoking (p = 0.036) was the only factor associated with CMD in men, whereas the left ventricular mass index (p = 0.010) and low glycated haemoglobin levels (p = 0.012) were associated with CMD in women.

CONCLUSIONS

Our results indicated that smoking status and EM use were associated with CMD. The risk of CMD differed between the two CMD components and sex. Although these factors should be considered when treating CMD, smoking cessation remains important. In addition, CMD assessment should be performed carefully when EM is used after ACh provocation. Further validation of our findings using prospective studies and large registries is warranted.

Thrombolysis in Myocardial Infarction Frame Count for Coronary Blood Flow Evaluation during Interventional Diagnostic Procedures

Background and Objectives: An interventional diagnostic procedure (IDP), including intracoronary acetylcholine (ACh) provocation and coronary physiological testing, is recommended as an invasive diagnostic standard for patients suspected of ischemia with no obstructive coronary arteries (INOCA). Recent guidelines suggest Thrombolysis In Myocardial Infarction frame count (TFC) as an alternative to wire-based coronary physiological indices for diagnosing coronary microvascular dysfunction. We evaluated trajectories of TFC during IDP and the impact of ACh provocation on TFC. Materials and Methods: This was a single-center, retrospective study. Patients who underwent IDP to diagnose INOCA were included and divided into two groups according to the positive or negative ACh provocation test. Wire-based invasive physiological assessment was preceded by ACh provocation tests and intracoronary isosorbide dinitrate (ISDN). We evaluated TFC at three different time points during IDP; pre-ACh, post-ISDN, and post-hyperemia. Results: Of 104 patients, 58 (55.8%) had positive ACh provocation test. In the positive ACh group, resting mean transit time (Tmn) and baseline resistance index were significantly higher than in the negative ACh group. Post-ISDN TFC was significantly correlated with resting Tmn (r = 0.31, p = 0.002). Absolute TFC values were highest at pre-ACh, followed by post-ISDN and post-hyperemia in both groups. All between-time point differences in TFC were statistically significant in both groups, except for the change from pre-ACh to post-ISDN in the positive ACh group. Conclusions: In patients suspected of INOCA, TFC was modestly correlated with Tmn, a surrogate of coronary blood flow. The positive ACh provocation test influenced coronary blood flow assessment during IDP.

Feeling connected to nature: validation of the connectedness to nature scale in the Italian context

Environmental issues are at the center of the political and cultural debate, representing one of the greatest challenges of our century. Sustainability and pro-environmental conducts are recognized as increasingly urgent to address the decay of ecosystems. To support the acquisition of attitudes that give greater consideration to environmental issues, experiencing a sense of connection with nature has been acknowledged in psychology as a particularly relevant individual component. Among the most commonly used scales in Anglo-Saxon context to analyses this feeling is the Connectedness to Nature Scale (CNS) assessing the emotional and experiential bond between humans and nature. To examine the reliability and validity of this scale in the Italian context, a study including 271 Italian adults (44,3% female; 55% males; Mean age = 34.70; SD = 13.584; age-range = 18-65 years) was conducted to establish evidence supporting the internal consistency of the CNS, as well as its ability to measure convergent, discriminant, and predictive validity. A Confirmatory Factor Analysis showed that CNS in Italian has a single-factor structure as reported in the original version by Mayer and Frantz. Furthermore, as expected, positive correlations were observed between the CNS and pro-environmental attitudes and negative correlations with civic moral disengagement. Finally, as assumed, the CNS positively correlated with mental well-being. A broad vision of this study concerns the idea that individuals who have a stronger connection with nature are likely to exhibit reduced tendencies to cause harm to it.