The impact of the coronary collateral circulation on mortality: a meta-analysis

Clinical Efficacy of Permanent Internal Mammary Artery Occlusion in Chronic Coronary Syndrome: A Double-Blind, Randomized, Sham-Controlled Trial

The Clinical Efficacy of Permanent Internal Mammary Artery Occlusion in Chronic Coronary Syndrome (CLIMACCS) trial, a randomized, sham-controlled trial, tested the clinical efficacy of permanent internal mammary artery (IMA) device occlusion on symptoms in patients with chronic coronary syndrome (CCS), coronary artery occlusive blood supply, and myocardial ischemia. This was a prospective trial in 101 patients with CCS randomly allocated (1:1) to IMA device occlusion (verum group) or to IMA sham intervention (placebo group). The primary study end point was the change in treadmill exercise time (ET) (ΔET in seconds) at 6 weeks after trial intervention. Secondary study end points were the changes in collateral flow index (CFI) and angina pectoris during a simultaneous 1-minute proximal balloon occlusion of a coronary artery. CFI is the ratio between simultaneous mean coronary occlusive, divided by mean aortic pressure, both subtracted by central venous pressure. In the verum and placebo groups, the ET changed from 398 ± 176 seconds to 421 ± 198s in the verum group (p = 0.1745) and from 426 ± 162 seconds to 430 ± 166 seconds in the placebo group (p = 0.55); ΔET amounted to +23 ± 116s and +4 ± 120 seconds, respectively (p = 0.44). CFI change during follow-up equaled +0.022 ± 0.061 in the verum and -0.039 ± 0.072 in the placebo group (p <0.0001). Angina pectoris at follow-up during the coronary balloon occlusion for CFI measurement had decreased or disappeared in 20 of 48 patients in the verum group and in 9 of 47 patients in the placebo group (p = 0.0242). In conclusion, permanent IMA device occlusion tends to augment treadmill ET in response to increased coronary artery occlusive blood supply, which is reflected by mitigated symptoms and signs of myocardial ischemia.

Association between the atherogenic index of plasma and coronary collateral circulation in patients with chronic total occlusion

BACKGROUND

The atherogenic index of plasma (AIP) is considered an independent risk factor for coronary artery disease (CAD). The present study investigated whether AIP correlates with the formation of coronary collateral circulation (CCC) in CAD patients with chronic total occlusion (CTO).

METHODS

This retrospective study included 1093 CAD patients with CTO confirmed by coronary angiography from January 2020 to December 2020 at Beijing Anzhen Hospital. Based on the Rentrop scoring system, the patients were divided into the good CCC group and the poor CCC group. AIP was calculated by log (triglyceride/high-density lipoprotein cholesterol). Meanwhile, the study population was further divided into four groups according to the quartiles of AIP.

RESULTS

Patients in the poor CCC group exhibited significantly higher AIP compared to those in the good CCC group (0.31 ± 0.27 vs. 0.14 ± 0.24, p < 0.001). Multivariate logistic regression analysis revealed an independent association between AIP and poor CCC, regardless of whether AIP was treated as a continuous or categorical variable (p < 0.001), after adjusting for confounding factors. Besides, this association remained consistent across most subgroups. The incorporation of AIP into the baseline model significantly enhanced the accuracy of identifying poor CCC [area under the curve (AUC): baseline model, 0.661 vs. baseline model + AIP, 0.721, p for comparison < 0.001].

CONCLUSIONS

Elevated AIP is independently associated with an increased risk of poor CCC in CAD patients with CTO, and AIP may improve the ability to identify poor CCC in clinical practice.

The Importance of Pan-Immune Inflammation Value (PIV) in Predicting Coronary Collateral Circulation in Stable Coronary Artery Patients

In this study, the correlation between pan-immune-inflammation value (PIV) and coronary collateral circulation (CCC) in patients with chronic coronary syndrome (CCS) was analyzed. The study included 663 patients with CCS who underwent coronary angiography and had coronary stenosis of ≥95% in at least one major coronary vessel. The participants were divided into two groups: good CCC (Rentrop score 2-3) and poor CCC (Rentrop score 0-1). PIV score was calculated as monocyte x platelet x neutrophil/lymphocyte count. When the patient groups who developed good and poor CCC were compared, neutrophil/lymphocyte ratio (NLR) (P < .001), C-reactive protein (CRP) levels, CRP/albumin ratio (CAR) (P < .001), systemic immune-inflammation index (SII) (P < .001), and PIV (P < .001) were higher in patients with poor CCC. In multivariate logistic regression analysis, age, SII, NLR, CRP, CAR, and PIV were found to be independent predictors of poor CCC (P < .001, for all). Receiver operating characteristic (ROC) analysis demonstrated that a cut-off value of 442.2 for PIV predicted poor CCC slightly better compared to other markers, with 76.8% sensitivity and 70.1% specificity (area under ROC curve = 0.808 (95% CI: 0.764-0.851), P < .001). These findings suggest that PIV can be used as an independent predictor of CCC development.

Vascular Endothelial Growth Factor (VEGF) and Its Role in the Cardiovascular System

Cardiovascular diseases remain the leading cause of death worldwide, with ischemic heart disease (IHD) as the most common. Ischemia-induced angiogenesis is a process in which vascular endothelial growth factor (VEGF) plays a crucial role. To conduct research in the field of VEGF's association in cardiovascular diseases, it is vital to understand its role in the physiological and pathological processes in the heart. VEGF-based therapies have demonstrated a promising role in preclinical studies. However, their potential in human therapies is currently under discussion. Furthermore, VEGF is considered a potential biomarker for collateral circulation assessment and heart failure (HF) mortality. Additionally, as VEGF is involved in angiogenesis, there is a need to elucidate the impact of VEGF-targeted therapies in terms of cardiovascular side effects.

Prognostic Nutritional Index is Associated with the Degree of Coronary Collateral Circulation in Stable Angina Patients with Chronic Total Occlusion

BACKGROUND

Coronary collateral circulation (CCC) can effectively improve myocardial blood supply to the area of CTO (chronic total coronary occlusion) and can, thus, improve the prognosis of patients with stable coronary syndrome (SCS). The degree of inflammation and some inflammation markers were associated with the development of collaterals.

OBJECTIVE

To investigate whether prognostic nutritional index (PNI) has an association with the development of CCC in patients with SCS.

METHODS

A total of 400 SCS patients with the presence of CTO in at least one major epicardial coronary artery were included in this study. The patients were divided into two groups according to the Rentrop score. Scores of 0 to 1 were considered poor developed CCC, and scores of 2 to 3 were accepted as good developed CCC. Statistical significance was set as a p-value < 0.05 for all analyses.

RESULTS

The mean age of the study cohort was 63±10 years; 273 (68.3%) were males. The poor-developed CCC group had a significantly lower PNI level compared with the good-developed CCC group (38.29±5.58 vs 41.23±3.85, p< 0.001). In the multivariate analysis, the PNI (odds ratio 0.870; 95% confidence interval 0.822-0.922; p< 0.001) was an independent predictor of poorly developed CCC.

CONCLUSION

The PNI can be used as one of the independent predictors of CCC formation. It was positively associated with the development of coronary collaterals in SCS patients with CTO.

Transcoronary Gradients of Mechanosensitive MicroRNAs as Predictors of Collateral Development in Chronic Total Occlusion

Background and Objectives: In this present study, we investigated the impact of mechanosensitive microRNAs (mechano-miRs) on the collateral development in 126 chronic total occlusion (CTO) patients, selected from 810 undergoing angiography. Materials and Methods: We quantified the collateral blood supply using the collateral flow index (CFI) and assessed the transcoronary mechano-miR gradients. Results: The patients with favorable collaterals had higher CFI values (0.45 ± 0.02) than those with poor collaterals (0.38 ± 0.03, p < 0.001). Significant differences in transcoronary gradients were found for miR-10a, miR-19a, miR-21, miR-23b, miR-26a, miR-92a, miR-126, miR-130a, miR-663, and let7d (p < 0.05). miR-26a and miR-21 showed strong positive correlations with the CFI (r = 0.715 and r = 0.663, respectively), while let7d and miR-663 were negatively correlated (r = -0.684 and r = -0.604, respectively). The correlations between cytokine gradients and mechano-miR gradients were also significant, including Transforming Growth Factor Beta with miR-126 (r = 0.673, p < 0.001) and Vascular Endothelial Growth Factor with miR-10a (r = 0.602, p = 0.002). A regression analysis highlighted the hemoglobin level, smoking, beta-blocker use, miR-26a, and miR-663 as significant CFI determinants, indicating their roles in modulating the collateral vessel development. Conclusions: These findings suggest mechanosensitive microRNAs as predictive biomarkers for collateral circulation, offering new therapeutic perspectives for CTO patients.

Hemoglobin in large vessel occlusion: Look further than collaterals

BACKGROUND

Abnormal hemoglobin (Hb) levels lead to poorer outcomes in ischemic stroke, though the mechanisms remain elusive. We aimed to study the role of Hb on imaging and clinical outcomes, namely on collaterals as it is a known mediator of infarct growth.

METHODS

Retrospective cohort study of patients with large vessel occlusion ischemic stroke admitted to our center. Demographics, clinical and imaging variables were collected, particularly baseline hemoglobin, presence of anemia and collateral score. Collaterals were scored from 0 to 3 and defined as poor if 0-1. Multivariable analyses were performed for collateral score and clinical outcomes (3-month mortality and good prognosis).

RESULTS

We included 811 patients, 215 (26.5 %) with anemia. Patients with anemia were older, had more comorbidities and more severe strokes. Hemoglobin levels and anemia were not associated with collateral score (OR 0.97, 95 % CI 0.89-1.05, p = 0.414 and OR 0.89, 95 % CI 0.64-1.24, p = 0.487, respectively) nor with poor collaterals (OR 0.96, 95 % CI 0.88-1.05, p = 0.398 and OR 0.86, 95 % CI 0.60-1.23, p = 0.406, respectively). Hb levels were associated with 3-month mortality (OR 0.85, 95 % CI 0.76-0.96, p = 0.008).

CONCLUSION

Hemoglobin or anemia were not found to be associated with collateral status. Our results raise further questions regarding the pathophysiology of anemia and outcomes in ischemic stroke, highlighting the need for future research.

Promoting collateral formation in type 2 diabetes mellitus using ultra-small nanodots with autophagy activation and ROS scavenging

BACKGROUND

Impaired collateral formation is a major factor contributing to poor prognosis in type 2 diabetes mellitus (T2DM) patients with atherosclerotic cardiovascular disease. However, the current pharmacological treatments for improving collateral formation remain unsatisfactory. The induction of endothelial autophagy and the elimination of reactive oxygen species (ROS) represent potential therapeutic targets for enhancing endothelial angiogenesis and facilitating collateral formation. This study investigates the potential of molybdenum disulfide nanodots (MoS2 NDs) for enhancing collateral formation and improving prognosis.

RESULTS

Our study shows that MoS2 NDs significantly enhance collateral formation in ischemic tissues of diabetic mice, improving effective blood resupply. Additionally, MoS2 NDs boost the proliferation, migration, and tube formation of endothelial cells under high glucose/hypoxia conditions in vitro. Mechanistically, the beneficial effects of MoS2 NDs on collateral formation not only depend on their known scavenging properties of ROS (H2O2, •O2-, and •OH) but also primarily involve a molecular pathway, cAMP/PKA-NR4A2, which promotes autophagy and contributes to mitigating damage in diabetic endothelial cells.

CONCLUSIONS

Overall, this study investigated the specific mechanism by which MoS2 NDs mediated autophagy activation and highlighted the synergy between autophagy activation and antioxidation, thus suggesting that an economic and biocompatible nano-agent with dual therapeutic functions is highly preferable for promoting collateral formation in a diabetic context, thus, highlighting their therapeutic potential.

Correlation between triglyceride glucose index and collateral circulation formation in patients with chronic total occlusion of coronary arteries in different glucose metabolic states

BACKGROUND

To investigate the correlation between triglyceride glucose index (TyG) and collateral circulation in patients with chronic total occlusion (CTO) of coronary arteries in different glucose metabolic states.

METHODS

A total of 681 patients who underwent coronary angiography between January 2020 and December 2021 to determine the presence of CTO lesions in at least one major coronary artery were retrospectively included in this study. Patients were categorized into a group with poor collateral circulation formation (Rentrop grade 0-1, n = 205) and a group with good collateral circulation formation (Rentrop grade 2-3, n = 476) according to the Rentrop scale. They were also categorized according to their glucose metabolism status: normal glucose regulation (NGR) (n = 139), prediabetes mellitus (Pre-DM) (n = 218), and diabetes mellitus (DM) (n = 324). Correlation between TyG index and collateral circulation formation was analyzed by logistic regression analysis and receiver operating characteristic (ROC) curves.

RESULTS

Among patients with CTO, TyG index was significantly higher in the group with poor collateral circulation formation than in the group with good collateral circulation formation. Logistic regression analysis showed that TyG index was an independent risk factor for poor collateral circulation formation (OR 5.104, 95% CI 3.323-7.839, P < 0.001). The accuracy of TyG index in predicting collateral circulation formation was evaluated by the ROC curve, which had an area under the curve of 0.779 (95% CI 0.738-0.820, P < 0.001). The restrictive cubic spline curves showed that the risk of poor collateral circulation formation in the Pre-DM and DM groups was initially flat and finally increased rapidly, except for the NGR group. TyG index was significantly associated with an increased risk of poor collateral circulation formation in the Pre-DM and DM groups.

CONCLUSIONS

TyG index was significantly associated with the risk of poor collateral circulation formation in patients with CTO, especially those with Pre-DM and DM.

Circulating secretoneurin level reflects angiographic coronary collateralization in stable angina patients with chronic total occlusion

OBJECTIVE

To investigate the association between circulating secretoneurin (SN) and angiographic coronary collateralization in stable angina patients with chronic coronary total occlusion (CTO).

METHODS

SN concentrations in serum were measured in 641 stable angina patients with CTO by radioimmunoassay. The status of coronary collaterals from the contra-lateral vessel was visually estimated using the Rentrop grading system, and was categorized into poor (grade 0 or 1) or good (grade 2 or 3) collateralization.

RESULTS

Serum SN levels were significantly higher in patients with good coronary collaterals compared to those with poor collaterals (175.23 ± 52.09 pmol/L vs. 143.29 ± 42.01 pmol/L, P < 0.001). Serum SN increased stepwise across Rentrop score 0 to 3 (P < 0.001), and increasing SN tertiles were associated with higher proportion of good coronary collateralization (OR, 1.907; 95% CI, 1.558 ~ 2.335, P < 0.001). After adjustment for confounding variables, serum SN (per tertile) remained an independent factor for predicting good coronary collaterals (OR, 1.870; 95% CI, 1.515 ~ 2.309; P < 0.001). Moreover, the diagnostic value of serum SN (per tertile) was consistent after stratifying patients based on gender, age, body mass index, hypertension, diabetes, history of smoking, severity of coronary artery disease and kidney function (OR: 1.511 ~ 2.680, P interaction ≥ 0.327).

CONCLUSION

Elevated circulating SN reflects good angiographic coronary collaterals in stable angina patients with CTO. The findings may provide insight into decision-making for these patients.

Effect of Fibroblast Growth Factor-21 Molecule on Coronary CollateralDevelopment

BACKGROUND

Collateral arteries provide an alternative source to the myocardium resulting from ischemia due to occlusive coronary artery disease and may help preserve myocardial function in the case of coronary artery disease (CAD). Although collateral development is so important, its pathophysiology has not been fully elucidated. Till now, no study has investigated the relationship between Fibroblast growth factor-21(FGF-21) and coronary collateral.

OBJECTIVE

This study aims to investigate the pathophysiology of coronary collateral development.

METHODS

In our study, which we planned as a case-control, 60 consecutive patients with ≥90 stenosis in at least one large coronary artery as a result of coronary angiography (CAG) and 30 patients with normal coronary angiography were included in the study cross-sectional. Demographic, echocardiographic and laboratory data were recorded. Coronary collateral circulation was evaluated using the Rentrop-Cohen method. FGF-21 levels were measured in all individuals.

RESULTS

In the analysis, no significant difference was observed between the two groups in basic biochemical parameters other than HDL (p>0.05 for all). FGF-21 level was statistically significantly higher in the patient group compared to the control group (p: 0.003). Also, the FGF-21 level was found to be statistically significantly higher in the good collateral circulation group than the poor (p:0.006). Univariate and multivariate logistic regression analysis was performed to predict the presence of collateral. We found that FGF-21(p=0.006), and C-reactive protein (p=0.020) predicted the presence of collateral independently.

CONCLUSION

Collateral formation and cardiac prognosis are closely related. Our study is the first to investigate the relationship between collateral formation and FGF-21. Our study showed that the FGF-21 level is an independent predictor of collateral formation. In addition, there was a significant difference between bad and good collateral formation regarding FGF-21 levels.

Microvascular Complications Are Associated With Coronary Collateralization in Type 2 Diabetes and Chronic Occlusion

CONTEXT

Coronary collateral (CC) vessel development appears to be protective with regard to adverse cardiovascular events and survival in patients with coronary chronic total occlusion (CTO). The influence of type 2 diabetes mellitus (T2DM) on CC growth has been controversial. In particular, the role of diabetic microvascular complications (DMC) in determining coronary collateralization has not been elucidated.

OBJECTIVE

To investigate whether patients with DMC presented differences in CC vessel presence and grading as compared with patients without DMC.

METHODS

We conducted a single-center observational study, including consecutive T2DM patients, without previous cardiovascular history, undergoing a clinically indicated coronary angiography for chronic coronary syndrome (CCS) and angiographic evidence of at least one CTO. Patients were subdivided into 2 study groups according to the presence/absence of at least one DMC (neuropathy, nephropathy, or retinopathy). The presence and grading of angiographically visible CC development from the patent vessels to the occluded artery were assessed using the Rentrop classification.

RESULTS

We enrolled 157 patients (mean age 68.6 ± 9.8 years; 120 [76.4%] men). Patients with DMC (75 [47.8%]) had a higher prevalence of CC (69 [92.0%] vs 62 [75.6%], P = .006) and high-grade CC (55 [73.3%] vs 39 [47.6%], P = .001) compared with those without, and we found a positive association between the number of DMC in each patient and the prevalence of high-grade CC.

CONCLUSION

Among T2DM patients with coronary CTO, the presence of DMC was associated with a high CC development.

Association of Coronary Collaterals and Myocardial Salvage Measured by Serial Cardiac Magnetic Resonance Imaging after Acute Myocardial Infarction

BACKGROUND

Coronary collateral flow in angiography has been linked with lower mortality rates in patients with coronary artery disease. However, the relevance of the underlying mechanism is sparse. Therefore, we tested the hypothesis that in patients with acute myocardial infarction (AMI), relevant coronary collateral flow is associated with more salvaged myocardium and lower risk of developing heart failure.

METHODS AND RESULTS

Patients with first AMI who received a percutaneous coronary intervention within 24 h after symptom onset were classified visually by assigning a Cohen-Rentrop Score (CRS) ranging between 0 (no collaterals) and 3 (complete retrograde filling of the occluded vessel). All 36 patients included in the analysis underwent cardiac magnetic resonance examination within 3 to 5 days after myocardial infarction and after 12 weeks. Patients with relevant collateral flow (CRS 2-3) to the infarct-related artery had significantly smaller final infarct size compared to those without (7 ± 4% vs. 20 ± 12%, p < 0.001). In addition, both groups showed improvement in left ventricular ejection fraction early after AMI, whereas the recovery was greater in CRS 2-3 (+8 ± 5% vs. +3 ± 5%, p = 0.015).

CONCLUSION

In patients with first AMI, relevant collateral flow to the infarct-related artery was associated with more salvaged myocardium at 12 weeks, translating into greater improvement of systolic left ventricular function. The protective effect of coronary collaterals and the variance of infarct location should be further investigated in larger studies.

Rag1 Deficiency Impairs Arteriogenesis in Mice

Increasing evidence suggests that lymphocytes play distinct roles in inflammation-induced tissue remodeling and tissue damage. Arteriogenesis describes the growth of natural bypasses from pre-existing collateral arteries. This process compensates for the loss of artery function in occlusive arterial diseases. The role of innate immune cells is widely understood in the process of arteriogenesis, whereas the role of lymphocytes remains unclear and is the subject of the present study. To analyze the role of lymphocytes, we induced arteriogenesis in recombination activating gene-1 (Rag1) knockout (KO) mice by unilateral ligation of the femoral artery. The lack of functional lymphocytes in Rag1 KO mice resulted in reduced perfusion recovery as shown by laser Doppler imaging. Additionally, immunofluorescence staining revealed a reduced vascular cell proliferation along with a smaller inner luminal diameter in Rag1 KO mice. The perivascular macrophage polarization around the growing collateral arteries was shifted to more pro-inflammatory M1-like polarized macrophages. Together, these data suggest that lymphocytes are crucial for arteriogenesis by modulating perivascular macrophage polarization.

Coronary Collateral Circulation: A New Predictor of Mortality in Heart Transplant Recipients With Allograft Vasculopathy

Coronary collateral arteries (CCAs) are anastomotic channels between vessels; although beneficial in atherosclerosis, their role in heart transplantation (HT) recipients is underinvestigated. CCAs initially develop as microcirculation and cardiac allograft vasculopathy (CAV), promoting immune-dependent proliferative angiogenic response, and play a role in their development. In our hypothesis, ischemia induced by coronary microvascular dysfunction (CMD) triggers the development of CCAs, which are, in turn, less functional as affected by CAV themselves.

Methods

One hundred twenty-one patients receiving HT at our institution were retrospectively evaluated and were included if transthoracic echocardiography with coronary flow velocity reserve (CFVR) assessment and coronary angiography were performed. CMD was defined as CFVR of ≤2.5. Patients with CAV were enrolled, and their angiograms were reviewed to evaluate the presence of CCAs. Cardiovascular mortality was assessed as the main clinical outcome.

Results

Forty patients were found to have CCAs. Patients with CCAs have lower CFVR than those without CCAs (2.22 ± 0.72 versus 2.69 ± 0.92;P = 0.003), reflecting in different rates of CMD in the 2 groups (72.5% versus 37%; P < 0.001). CMD is associated with higher CAV grades (P < 0.001), which are also associated with CCAs (P < 0.001). Patients with poorly developed CCAs have lower CFVR (P < 0.001). At multivariable analysis, CMD (P = 0.008) and higher CAV grades (P = 0.005) are independent predictors of CCAs. During the median follow-up time of 10.2 (6.6-13.3) y, patients with CCAs have been found to have higher mortality than those without CCAs (57.5% versus 32.1%; P = 0.007). CCAs are associated with a lower probability of survival also in patients with CMD (P < 0.001) and are independent predictors of mortality (P < 0.001).

Conclusions

Our results demonstrate an interplay between CAV, CMD, and CCAs. We confirm that CAV is associated with CMD, and we show, for the first time, that CMD is associated with CCAs. CCAs are pathophysiologically associated with more severe graft vasculopathy and independently predict mortality after HT.

The association of serum uric acid/albumin ratio with the development of coronary collateral circulation in patients with chronic total occluded coronary arteries

Introduction: Coronary collateral circulation (CCC) develops in chronic total occluded (CTO) vessels and protects the myocardium against ischemia in addition to the improvement of cardiac functions. Poor CCC is related to adverse cardiac events as well as poor prognosis. Serum uric acid/albumin ratio (UAR) has emerged as a novel marker associated with poor cardiovascular outcomes. We aimed to investigate whether there was an association between UAR and poor CCC in CTO patients. Methods: This study was comprised of 212 patients with CTO (92 with poor CCC and 120 with good CCC). All patients were graded based on Rentrop scores to poor CCC (Rentrop scores 0 and 1) and good CCC (Rentrop scores 2 and 3). Results: Poor CCC patients had higher frequencies of diabetes mellitus, triglyceride levels, Syntax and Gensini scores, uric acid, and UAR and lower lymphocyte, high-density lipoprotein cholesterol, and ejection fraction when compared to good CCC patients. UAR was an independent predictor of poor CCC in CTO patients. Furthermore, UAR had a better discriminative ability for patients with poor CCC from good CCC compared to serum uric acid and albumin. Conclusion: Based on the results of the study, the UAR could be used to detect poor CCC in CTO patients.

Past Myocardial Infarctions and Gender Predict the LVEF Regardless of the Status of Coronary Collaterals: An AI-Informed Research

BACKGROUND: The degree of the development of coronary collaterals is long considered an alternate – that is, a collateral – source of blood supply to an area of the myocardium threatened with vascular ischemia or insufficiency. Hence, the coronary collaterals are beneficial but can also promote harmful (adverse) effects. For instance, the coronary steal effect during the myocardial hyperemia phase and that of restenosis following coronary angioplasty. OBJECTIVES: Our study explores the contribution of coronary collaterals – if any exist – while considering other potential predictors, including demographics and medical history, toward the left ventricular (LV) dysfunction measured through the LV ejection fraction (LVEF). METHODS: Our cross-sectional design study used convenience sampling of 100 patients (n = 100; a male-to-female ratio of 4:1). We conducted frequentist inference statistics using IBM-SPSS version 24 and Microsoft Office Excel 2016 with the analysis ToolPak plugin; we ran parallel neural networks (supervised machine learning (ML)) and a two-step clustering (non-supervised ML) for robust conjoint inference with frequentist statistics. RESULTS: The past incidents of myocardial infarction (p = 0.036) and gender (p = 0.072) influenced the LVEF; both are significant predictors at a 90% confidence interval. We found that gender and past incidents of MI influenced the LVEF regardless of the status of coronary collaterals. Our study did not yield any positive or significant findings concerning the status of coronary collaterals or the coronary circulation dominance patterns. CONCLUSION: Regardless of the status of coronary collaterals, we verified that the female gender is protective of the LV function, contrary to the past infarction incidents that predispose to a deteriorated LV function. Our study’s innovation relates to its status as the first study from India to explore the coronary collaterals and the ejection fraction while incorporating frequentist statistics and narrow artificial intelligence to infer reliable results.

Study of blood rheological parameters and NO in coronary artery disease patients with and without collaterals

BACKGROUND

In coronary artery disease (CAD), an alternative way of improvement of blood circulation in the ischemic area of the myocardium is coronary collateral circulation. Our study aimed to investigate the rheological parameters of blood and nitric oxide (NO) content in patients with various degrees of collateral development and the likelihood of the influence of blood fluidity on collateral angiogenesis.

METHODS

We studied patients with stable CAD who underwent elective coronary angiography and a control group with the same mean age. We investigated patients with different degrees of developing collaterals and those without them. In studied patients, the blood plasma viscosity, aggregability, and deformability of erythrocytes, as the main indicators of blood rheology. We recorded content of stable metabolic end products of nitric oxide (NOx).

RESULTS

Results of the studies showed that in the blood of studied patients with CAD erythrocyte aggregation was increased and NO content decreased compared to the control level; NO content was as lower, as less was the number of developed collaterals was recorded.

CONCLUSION

In this work, the role of the aggregation ability of erythrocytes and the endothelial origin of NO in the direct and feedback regulatory mechanism of angiogenesis in patients with CAD are discussed.

Good coronary collateral circulation is not associated with better prognosis in patients with chronic total occlusion, regardless of treatment strategy

OBJECTIVE

This study aimed to assess the effects of coronary collateral circulation (CCC) on the prognosis of patients with chronic total occlusion (CTO) under different treatment strategies.

METHODS

We analyzed a total of 1124 patients who were diagnosed with CTO and divided them into groups with good CCC (grade 2 to 3, n = 539) or poor CCC (grade 0 to 1, n = 531). The primary outcome was cardiac death during follow-up; the secondary outcome was major adverse cardiovascular events (MACEs). We also performed subgroup analyses in groups with and without CTO revascularization (CTO-R and CTO-NR, respectively), and sensitivity analyses excluding patients who received failed CTO-PCI to further investigate the effect of CCC.

RESULTS

During a median follow-up duration of 23 months, we did not detect any significant differences between the good CCC group and the poor CCC group in terms of cardiac death (4.2% vs 4.1%; adjusted hazard ratio [HR], 1.01; 95% confidence interval [CI], 0.56-1.83; p = 0.970) and MACEs (23.6% vs 23.2%; adjusted HR, 1.07; 95% CI, 0.84-1.37; p = 0.590). Subgroup analyses according to CTO revascularization showed similar results. In addition, we observed no differences in sensitivity analyses when patients who received failed CTO-PCI were excluded.

CONCLUSION

Good CCC was not associated with a lower risk of cardiac death or MACEs among patients with CTO, regardless of whether the patients received CTO revascularization treatment.

C1q/TNF-related protein-2 improved angiogenesis to protect myocardial function during ischaemia‒reperfusion

BACKGROUND

Collateral growth plays an important role in the recovery of acute myocardial infarction. C1q/TNF-related protein-2 (CTRP2), a CTRP family member, showed some protective effects on cell survival. In this study, the relationship between CTRP2 and collateral growth was examined.

METHODS

C57BL/6 mice were subjected to myocardial ischaemia/reperfusion (I/R), and the expression of CTRP2 and the effect of CTRP2 on infarction size, cardiac function and angiogenesis were examined. The ischaemic hindlimb model was also used to examine the effect of CTRP2. In vitro, CTRP2-mediated regulation of angiogenesis, AKT activation and VEGFR2 expression in endothelial cells was examined. The CTRP2 level associated with good collateral growth was observed in a cohort.

RESULTS

I/R reduced CTRP2 expression, and intraperitoneal injection of recombinant CTRP2 protein improved infarction size, cardiac function and angiogenesis. Overexpression of CTRP2 promoted blood refusion and collateral growth in ischaemic hindlimb mice. In vitro, CTRP2 enhanced tube formation and migration in a dose-dependent manner, while CTRP2 increased AKT phosphorylation and VEGFR2 expression. In an observational clinical cohort, CTRP2 levels were significantly increased in patients with good collateral growth, and CTRP2 was negatively associated with poor collateral growth in patients.

CONCLUSION

CTRP2 improved cardiac function by promoting collateral growth by promoting AKT-VEGFR2.

The relationship between mean platelet volume lymphocyte ratio and collateral circulation in patients with chronic total coronary occlusion

Objective

To correlate mean platelet volume lymphocyte ratio (MPVLR) and coronary collateral circulation (CCC) in patients with chronic total occlusion (CTO).

Materials and methods

A total of 643 patients who were hospitalized at a single large academic medical center from January 2020 to October 2021 and had CTO lesions in at least one major coronary artery confirmed by coronary angiography were retrospectively analyzed. Patients were divided according to the Rentrop criteria into poorly formed CCC (Rentrop grade 0–1, n = 235) and well-formed CCC (Rentrop grade 2–3, n = 408) groups. Mean platelet volume lymphocyte ratio (MPVLR) was calculated from routine laboratory data (MPV divided by lymphocyte count). The clinical data of the two groups were compared, and relationships between MPVLR and CCC formation were analyzed.

Results

The MPVLR of patients with poorly formed CCC was significantly higher than that of patients with well-formed CCC (7.82 ± 3.80 vs. 4.84 ± 1.42, P &lt; 0.01). The prevalence of diabetes mellitus and C-reactive protein levels were significantly higher in the poor CCC group than in the good CCC group (P &lt; 0.01), while the proportions of patients with CTO or multivessel lesions in the right coronary artery were significantly lower in the poor CCC group than in the good CCC group (P &lt; 0.01). Multivariate logistic regression analysis identified MPVLR (OR: 2.101, 95% CI: 1.840–2.399, P &lt; 0.01), C-reactive protein level (OR: 1.036, 95% CI: 1.008–1.064, P &lt; 0.05), a history of diabetes mellitus (OR: 2.355, 95% CI: 1.532–3.621, P &lt; 0.01), and right coronary CTO ratio (OR: 0.313, 95% CI: 0.202–0.485, P &lt; 0.01) as independent risk factors for CCC formation. The area under the ROC curve of MPVLR for predicting poorly formed CCC was 0.82 (95% CI: 0.784–0.855, P &lt; 0.01), the best cut-off point was 6.02 and the sensitivity and specificity of MPVLR for predicting poorly formed CCC were 72.3 and 82.4%, respectively.

Conclusion

In patients with coronary CTO, MPVLR was negatively correlated with CCC and a high MPVLR level was an independent predictor of poorly formed CCC.

Early recruitable coronary collaterals preserve miocardial viability in late presentation infarctions

BACKGROUND

Previous studies showed conflicting results regarding the contribution of coronary collateral circulation (CCC) to myocardial perfusion and function in the setting of myocardial infarction (MI). In the primary angioplasty era, the role of CCC in these studies may have been influenced by the effect of early reperfusion. The true impact of CCC could be clarified by studying its effect on nonreperfused patients. The aim of our study was to evaluate the effect of CCC on myocardial viability of late presentation MI.

METHODS AND RESULTS

Between 2008 and 2019, we included 167 patients with a late presentation MI who had a complete angiographic occlusion in a major coronary artery in which myocardial viability of the culprit territory was assessed. Patients were divided according to the presence of angiographic early recruited CCC (ERCC) (Rentrop 2-3) or poor CCC (PCC) (Rentrop 0-1). A lower left ventricular ejection function (LVEF) at discharge (54.2 ± 9 vs. 47.9 ± 12; <0.01) and a more severe left ventricular wall motion abnormalities in the culprit territory were observed in PCC patients. The presence of ERCC was the main independent predictor of myocardial viability in late presentation MI (hazard ratio, 4.24; 95% confidence interval, 1.68-10.6; P < 0.001). At follow-up, wall motion score increased significantly (2.05 ± 0.16; P = 0.02) in patients with ERCC but not in PCC patients (0.07 ± 0.16; P = 0.4), and LVEF improvement was significantly higher in ERCC than in PCC patients (9.7 ± 2.6 vs. 3.8 ± 4.2; P = 0.02).

CONCLUSION

The presence of ERCC was the main independent predictor of myocardial viability in late presentation MI.

Relação entre o Índice Imune-inflamação Sistêmico e Circulação Colateral Coronariana em Pacientes com Oclusão Total Crônica

Fundamento

Objetivos

Métodos

Resultados

Conclusões

Are There Any Cardioprotective Effects or Safety Concerns of Erythropoietin in Patients With Myocardial Infarction? A Systematic Review

Myocardial infarction (MI) is a global cause of morbidity and mortality. MI is the outcome of a chronic process termed atherosclerosis, a buildup of fatty and other substances called plaques inside the coronary vessels, causing hardening and thickening of the arterial wall. Erythropoietin (EPO) is a pleiotropic cytokine released mainly by the kidneys in adults. Besides its well-known erythropoietic functions, EPO possesses anti-apoptotic, mitogenic, and angiogenic effects. This review aims to analyze the strength of any therapeutic or protective value of EPO on the heart and safety concerns regarding its administration in MI individuals.

This systematic review was performed based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Four databases (PubMed, PubMed Central, Google Scholar, and Sciences Direct) were employed to search for articles published in the last 10 years. Focused studies were relevant articles in the English language, trials, reviews, meta-analyses, and studies with a control group. Following the quality assessment process, nine studies were eligible and hence were included in the review consisting of six randomized controlled trials and three systematic reviews and meta-analyses. Contrary to preclinical studies, EPO administration did not significantly have notable effects on mortality, major adverse cardiovascular events, or infarction size reduction. Significant left ventricle ejection fraction amelioration was not appreciated either. However, EPO seems to reduce the incidence of post-MI arrhythmias.

Cardiac pericyte reprogramming by MEK inhibition promotes arteriologenesis and angiogenesis of the ischemic heart

Pericytes (PCs) are abundant yet remain the most enigmatic and ill-defined cell population in the heart. Here, we investigated whether PCs can be reprogrammed to aid neovascularization. Primary PCs from human and mouse hearts acquired cytoskeletal proteins typical of vascular smooth muscle cells (VSMCs) upon exclusion of EGF/bFGF, which signal through ERK1/2, or upon exposure to the MEK inhibitor PD0325901. Differentiated PCs became more proangiogenic, more responsive to vasoactive agents, and insensitive to chemoattractants. RNA sequencing revealed transcripts marking the PD0325901-induced transition into proangiogenic, stationary VSMC-like cells, including the unique expression of 2 angiogenesis-related markers, aquaporin 1 (AQP1) and cellular retinoic acid-binding protein 2 (CRABP2), which were further verified at the protein level. This enabled us to trace PCs during in vivo studies. In mice, implantation of Matrigel plugs containing human PCs plus PD0325901 promoted the formation of αSMA+ neovessels compared with PC only. Two-week oral administration of PD0325901 to mice increased the heart arteriolar density, total vascular area, arteriole coverage by PDGFRβ+AQP1+CRABP2+ PCs, and myocardial perfusion. Short-duration PD0325901 treatment of mice after myocardial infarction enhanced the peri-infarct vascularization, reduced the scar, and improved systolic function. In conclusion, myocardial PCs have intrinsic plasticity that can be pharmacologically modulated to promote reparative vascularization of the ischemic heart.

The prognostic value of the CHA2DS2-VASc score in coronary collateral circulation and long-term mortality in coronary artery disease

BACKGROUND

The CHA2DS2-VASc score is used to determine thromboembolic risk in cases of atrial fibrillation. The predictive value of this score in predicting coronary collateral circulation in chronic total occlusion is unknown.

OBJECTIVE

The aim of this study was to investigate the relationship between the CHA2DS2-VASc score and coronary collateral circulation in patients with chronic total occlusion.

METHODS

A total of 189 patients, who underwent coronary angiography and had a chronic total occlusion in at least one coronary artery, were enrolled in this study. The Rentrop scoring system was used for grouping the patients, and patients were classified as having poorly developed coronary collateral circulation (Rentrop grade 0 or 1) or well-developed coronary collateral circulation (Rentrop grade 2 or 3).

RESULTS

The CHA2DS2-VASc score of the good coronary collateral circulation group was significantly lower than the other group (3.1±1.7 vs. 3.7±1.7, p=0.021). During the follow-up period, 30 (32.2%) patients in the poorly developed coronary collateral circulation group and 16 (16.7%) patients in the well-developed coronary collateral circulation group died (p=0.028). According to the multivariable Cox regression model, the CHA2DS2-VASc score [hazard ratio (HR): 1.262, p=0.009], heart rate (HR: 1.049, p=0.003), LVEF (HR: 0.975, p=0.039), mean platelet volume (HR: 1.414, p=0.028), and not taking acetylsalicylic acid during admission (HR: 0.514, p=0.042) were independently associated with a higher risk of mortality.

CONCLUSIONS

The CHA2DS2-VASc score is closely related to coronary collateral development and predicts mortality in patients with chronic total occlusion.

Increased estimated remnant-like particle cholesterol is associated with impaired coronary collateralization in patients with coronary chronic total occlusions

AIMS

This study intends to explore whether, or to what extent, the estimated remnant-like particle cholesterol was associated with coronary collateralization in patients with chronic total occlusion lesions.

METHODS

792 patients with at least one coronary chronic total occlusion lesion were enrolled. Serum level of lipid profiles were determined and the estimated remnant-like particle cholesterol was calculated. The development of coronary collateralization was graded as low (Rentrop score 0-1) or high (Rentrop score 2-3) collateralization according to the Rentrop classification system and then the association between the estimated remnant-like particle cholesterol and collateralization was assessed.

RESULTS

222 participants were classified into low collateralization group. The estimated remnant-like particle cholesterol level was significantly higher in low collateralization (P < 0.001) and type 2 diabetes mellitus (P = 0.009) group. To further explore the association between the estimated remnant-like particle cholesterol and the development of coronary collateralization, these patients were divided into 3 groups based on the estimated remnant-like particle cholesterol tertiles. The prevalence of low collateralization increased stepwise with the tertile groups (T1 12.5% vs. 27.1% vs. 45.3%, P < 0.001). Multivariate logistic regression analysis showed that the estimated remnant-like particle cholesterol was independently associated with the under-developed collateralization, with an OR and 95%CI of 2.34 (1.46-3.74) and 4.91 (3.01-8.02) in the T2 and T3 group, respectively. The following receiver-operating characteristic analysis indicated that the diagnostic value of estimated remnant-like particle cholesterol for the low collateralization was 0.696, with a cut-off value of 0.485, and its sensitivity was 82.88%. Besides, the addition of the estimated remnant-like particle cholesterol into the baseline model consisting of traditional risk factors could improve the incremental value of the discrimination of impaired collateralization only in overall and type 2 diabetes mellitus populations.

CONCLUSIONS

The increased estimated remnant-like particle cholesterol is independently associated with impaired collateralization in patients with coronary chronic total occlusion lesions. Therapies targeting at remnant-like particle cholesterol may be needed in advanced coronary artery disease patients with type 2 diabetes mellitus not suitable for vascular revascularization.

With a Little Help From My Friends: the Role of the Renal Collateral Circulation in Atherosclerotic Renovascular Disease

The collateral circulation can adapt to bypass major arteries with limited flow and serves a crucial protective role in coronary, cerebral, and peripheral arterial disease. Emerging evidence indicates that the renal collateral circulation can similarly adapt and thereby limit kidney ischemia in atherosclerotic renovascular disease. These adaptations predominantly include recruitment of preexisting microvessels for arteriogenesis, with de novo vessel formation playing a limited role. Yet, adaptations of the renal collateral circulation in renovascular disease are often insufficient to fully compensate for the limited flow within an obstructed renal artery and may be hampered by the severity of obstruction or patient comorbidities. Experimental strategies have attempted to circumvent limitations of collateral formation and improve the prognosis of patients with various ischemic vascular territories. These have included pharmacological approaches such as endothelial growth factors, renin-angiotensin-aldosterone system blockade, and If-channel-blockers, as well as interventions like preconditioning, exercise, enhanced external counter-pulsation, and low-energy shock-wave therapy. However, few of these strategies have been implemented in atherosclerotic renovascular disease. This review summarizes current understanding regarding the development of renal collateral circulation in atherosclerotic renovascular disease. Studies are needed to apply lessons learned in other vascular beds in the setting of atherosclerotic renovascular disease to develop new treatment regimens for this patient group.

Simultaneous Upregulation of Elastolytic and Elastogenic Factors Are Necessary for Regulated Collateral Diameter Expansion

Background: During arteriogenesis, outward remodeling of the arterial wall expands luminal diameter to produce increased conductance in developing collaterals. We have previously shown that diameter expansion without loss of internal elastic lamina (IEL) integrity requires both degradation of elastic fibers and LOX-mediated repair. The aim of this study was to investigate the expression of genes involved in remodeling of the extracellular matrix (ECM) using a model of arteriogenesis. Methods: Sprague-Dawley rats underwent femoral artery ligation with distal arteriovenous fistula (FAL + AVF) placement. Profunda femoral arteries (PFA) were harvested for analysis at various time points. Serum desmosine, an amino acid found exclusively in elastin, was evaluated with enzyme-linked immunosorbent assay (ELISA) as a marker of tissue elastolysis. Tissue mRNA isolated from FAL + AVF exposed PFAs was compared to the contralateral sham-operated using qPCR. HCAECs were cultured under low shear stress (8 dyn·s/cm 2) for 24 h and then exposed to high shear stress (40 dyn·s/cm 2) for 2-6 h. Primers used included FBN-1, FBN-2, Timp-2, LOX-1, Trop-E, Cath-K, Cath-S, MMP-2, MMP-9, FBLN-4, and FBLN-5 and were normalized to GAPDH. mRNA fold changes were quantified using the 2-ΔΔCq method. Comparisons between time points were made with non-parametric ANOVA analysis with Bonferroni adjustment. Results: PFAs showed IEL reorganization during arteriogenesis. Serum desmosine levels are significantly elevated at 2 days and one week, with a return to baseline thereafter (p < 0.01). Expression of ECM structural proteins (FBN-1, FBN-2, FBLN-4, FBLN-5, Tropoelastin, TIMP-2, LOX-1) and elastolytic proteins (MMP-2, MMP-9, Cathepsin S, Cathepsin K) exhibited an early peak (p < 0.05) relative to sham PFAs. After two weeks, expression returned to baseline. HCAECs demonstrated upregulation of FBN-2, FBLN-5, LOX-1 and Trop-E at 4 h of high shear stress, as well as elastolytic protein MMP-2. Conclusions: Elastin degradation begins early in arteriogenesis and is mediated by local upregulation of elastolytic genes. Elastolysis appears to be simultaneously balanced by production of elastic fiber components which may facilitate stabilization of the IEL. Endothelial cells are central to initiation of arteriogenesis and begin ECM remodeling in response to altered shear stress.

The essential role for endothelial cell sprouting in coronary collateral growth

RATIONALE

Coronary collateral growth is a natural bypass for ischemic heart diseases. It offers tremendous therapeutic benefit, but the process of coronary collateral growth isincompletely understood due to limited preclinical murine models that would enable interrogation of its mechanisms and processes via genetic modification and lineage tracing. Understanding the processes by which coronary collaterals develop can unlock new therapeutic strategies for ischemic heart disease.

OBJECTIVE

To develop a murine model of coronary collateral growth by repetitive ischemia and investigate whether capillary endothelial cells could contribute to the coronary collateral formation in an adult mouse heart after repetitive ischemia by lineage tracing.

METHODS AND RESULTS

A murine model of coronary collateral growth was developed using short episodes of repetitive ischemia. Repetitive ischemia stimulation resulted in robust collateral growth in adult mouse hearts, validated by high-resolution micro-computed tomography. Repetitive ischemia-induced collateral formation compensated ischemia caused by occlusion of the left anterior descending artery. Cardiac function improved during ischemia after repetitive ischemia, suggesting the improvement of coronary blood flow. A capillary-specific Cre driver (Apln-CreER) was used for lineage tracing capillary endothelial cells. ROSA mT/mG reporter mice crossed with the Apln-CreER transgene mice underwent a 17 days' repetitive ischemia protocol for coronary collateral growth. Two-photon and confocal microscopy imaging of heart slices revealed repetitive ischemia-induced coronary collateral growth initiated from sprouting Apelin⁺ endothelial cells. Newly formed capillaries in the collateral-dependent zone expanded in diameter upon repetitive ischemia stimulation and arterialized with smooth muscle cell recruitment, forming mature coronary arteries. Notably, pre-existing coronary arteries and arterioles were not Apelin⁺, and all Apelin⁺ collaterals arose from sprouting capillaries. Cxcr4, Vegfr2, Jag1, Mcp1, and Hif1⍺ mRNA levels in the repetitive ischemia-induced hearts were also upregulated at the early stage of coronary collateral growth, suggesting angiogenic signaling pathways are activated for coronary collaterals formation during repetitive ischemia.

CONCLUSIONS

We developed a murine model of coronary collateral growth induced by repetitive ischemia. Our lineage tracing study shows that sprouting endothelial cells contribute to coronary collateral growth in adult mouse hearts. For the first time, sprouting angiogenesis is shown to give rise to mature coronary arteries in response to repetitive ischemia in the adult mouse hearts.

Association of Visceral Obesity-Related Indices With Coronary Collateralization in Patients With Chronic Total Occlusion

Background: Obesity is an independent risk factor for cardiovascular disease. We investigated whether and to what extent visceral obesity-related indices were associated with coronary collateralization (CC) in chronic total occlusion (CTO) patients.

Methods: This retrospective cohort study involved 1,008 consecutive patients with CTO who underwent CTO-percutaneous coronary artery intervention (PCI). CC was graded according to the Rentrop scoring system. Data on demographic and clinical characteristics were collected by cardiovascular doctors. Logistic regression, receiver operating characteristic (ROC) curve and Kaplan-Meier analyses were performed to assess the predictive value of visceral obesity-related indices for CC.

Results: Overall, 1,008 inpatients were assigned to the poor CC group (n = 592) and good CC group (n = 416). In multivariate-adjusted logistic regression analyses, all visceral obesity-related indices (P-value < 0.001) were significantly associated with CC. After ROC analysis and the Delong test, the Chinese visceral adiposity index (CVAI) had the largest area under the curve (AUC) of 0.741 (0.711–0.771). Further analysis revealed that CVAI quartile remained a risk factor for poor CC in all groups, CVAI was associated with a 1.018-fold higher risk of poor CC (OR = 1.018, 95% CI: 1.014–1.021, P < 0.001). Individuals in the top CVAI quartile group had the highest risk of poor CC (OR = 10.657, 95% CI: 6.492–17.493, P < 0.001). Subgroup analyses showed similar results, and CVAI quartile remained a risk factor for poor CC. Moreover, increased CVAI predicted poor prognosis in CTO patients.

Conclusion: In summary, this study indicated that all the increased visceral obesity-related indices were significantly associated with increased poor CC risk. After adjusting for potential risks, CVAI had the best performance for estimating CC and predicting prognosis in CTO patients.

Structural Remodeling of the Extracellular Matrix in Arteriogenesis: A Review

Lower extremity arterial occlusive disease (AOD) results in significant morbidity and mortality for the population, with up to 10% of patients ultimately requiring amputation. An alternative method for non-surgical revascularization which is yet to be fully understood is the optimization of the body's own natural collateral arterial network in a process known as arteriogenesis. Under conditions of conductance vessel stenosis or occlusion resulting in increased flow, shear forces, and pressure gradients within collaterals, positive remodeling occurs to increase the diameter and capacity of these vessels. The creation of a distal arteriovenous fistula (AVF) will drive increased arteriogenesis as compared to collateral formation with the occlusion of a conductance vessel alone by further increasing flow through these arterioles, demonstrating the capacity for arteriogenesis to form larger, more efficient collaterals beyond what is spontaneously achieved after arterial occlusion. Arteries rely on an extracellular matrix (ECM) composed of elastic fibers and collagens that provide stability under hemodynamic stress, and ECM remodeling is necessary to allow for increased diameter and flow conductance in mature arterial structures. When positive remodeling occurs, digestion of lamella and the internal elastic lamina (IEL) by matrix metalloproteinases (MMPs) and other elastases results in the rearrangement and thinning of elastic structures and may be replaced with disordered elastin synthesis without recovery of elastic function. This results in transmission of wall strain to collagen and potential for aneurysmal degeneration along collateral networks, as is seen in the pancreaticoduodenal artery (PDA) after celiac occlusion and inferior mesenteric artery (IMA) with concurrent celiac and superior mesenteric artery (SMA) occlusions. Further understanding into the development of collaterals is required to both better understand aneurysmal degeneration and optimize collateral formation in AOD.

Predictors of Adverse Events Among Chronic Total Occlusion Patients Undergoing Successful Percutaneous Coronary Intervention and Medical Therapy

Objective

Limited data are available on the predictors of major adverse cardiac events (MACE) after a successful coronary chronic total occlusion (CTO) percutaneous coronary intervention (PCI) and medical therapy. This study aimed to identify predictors of MACE in CTO patients undergoing successful recanalization and medical therapy.

Methods

A total of 2015 patients with CTOs were enrolled. About 718 patients underwent successful CTO recanalization, and 1297 patients received medical therapy. The primary outcome was the frequency of MACE, defined as a composite of cardiac death, myocardial infarction, and target-vessel revascularization. Multivariate models were used to determine predictors of MACE.

Results

In successful CTO recanalization group, MACE occurred in 123 (17.1%) patients. In multivariate analysis, heart failure (hazard ratio [HR] 1.77, 95% confidence interval [CI]: 1.04–3.04, p = 0.036) was identified as independent predictors for MACE in successful CTO recanalization. Additionally, in medical therapy group, the significant predictors of MACE were male gender (HR 1.53, 95% CI: 1.13–2.05, p = 0.005), diabetes mellitus (HR 1.39, 95% CI: 1.11–1.74, p = 0.003), heart failure (HR 1.44, 95% CI: 1.10–1.87, p = 0.007), J-CTO score (HR 1.17, 95% CI: 1.07–1.28, p = 0.001) and multivessel disease (HR 2.20, 95% CI: 1.42–3.39, p < 0.001).

Conclusion

Heart failure was predictor for composite cardiovascular events in patients with CTO after successful recanalization. Male gender, diabetes mellitus, heart failure, J-CTO score and multivessel disease were predictors of MACE in CTO patients with medical therapy.

The association of interferon-alpha with development of collateral circulation after artery occlusion

Background

Previous studies have demonstrated that interferon (IFN) signaling is enhanced in patients with poor collateral circulation (CC). However, the role and mechanisms of IFN‐alpha in the development of CC remain unknown.

Methods

We studied the serum levels of IFN‐alpha and coronary CC in a case–control study using logistics regression, including 114 coronary chronic total occlusion (CTO) patients with good coronary CC and 94 CTO patients with poor coronary CC. Restricted cubic splines was used to flexibly model the association of the levels of IFN‐alpha with the incidence of good CC perfusion restoration after systemic treatment with IFN‐alpha was assessed in a mice hind‐limb ischemia model.

Results

Compared with the first IFN‐alpha tertile, the risk of poor CC was higher in the third IFN‐alpha tertile (OR: 4.79, 95% CI: 2.22–10.4, p < .001). A cubic spline‐smoothing curve showed that the risk of poor CC increased with increasing levels of serum IFN‐alpha. IFN‐alpha inhibited the development of CC in a hindlimb ischemia model. Arterioles of CC in the IFN‐alpha group were smaller in diameter than in the control group.

Conclusion

Patients with CTO and with poor CC have higher serum levels of IFN‐alpha than CTO patients with good CC. IFN‐alpha might impair the development of CC after artery occlusion.

Financial Estimation of the Uncertainty in Medicine Using Present Value of Medical Fees and a Mortality Risk Prediction Model: a Retrospective Cohort Study

This study aimed to develop a method to enable the financial estimation of each patient’s uncertainty without focusing on healthcare technology. We define financial uncertainty (FU) as the difference between an actual amount of claim (AC) and the discounted present value of the AC (DAC). DAC can be calculated based on a discounted present value calculated using a cash flow, a period of investment, and a discount rate. The present study considered these three items as AC, the length of hospital stay, and the predicted mortality rate. The mortality prediction model was built using typical data items in standard level electronic medical records such as sex, age, and disease information. The performance of the prediction model was moderate because an area under curve was approximately 85%. The empirical analysis primarily compares the FU of the top 20 diseases with the actual AC using a retrospective cohort in the University of Miyazaki Hospital. The observational period is 5 years, from April 1, 2013, to March 31, 2018. The analysis demonstrates that the proportion of FU to actual AC is higher than 20% in low-weight children, patients with leukemia, brain tumor, myeloid leukemia, or non-Hodgkin’s lymphoma. For these diseases, patients cannot avoid long hospitalization; therefore, the medical fee payment system should be designed based on uncertainty. Our method is both practical and generalizable because it uses a small number of data items that are required in standard electronic medical records. This method contributes to the decision-making processes of health policymakers.

Hypoxia Inducible Factors as Central Players in the Pathogenesis and Pathophysiology of Cardiovascular Diseases

Cardiovascular (CV) diseases are the major cause of death in industrialized countries. The main function of the CV system is to deliver nutrients and oxygen to all tissues. During most CV pathologies, oxygen and nutrient delivery is decreased or completely halted. Several mechanisms, including increased oxygen transport and delivery, as well as increased blood flow are triggered to compensate for the hypoxic state. If the compensatory mechanisms fail to sufficiently correct the hypoxia, irreversible damage can occur. Thus, hypoxia plays a central role in the pathogenesis and pathophysiology of CV diseases. Hypoxia inducible factors (HIFs) orchestrate the gene transcription for hundreds of proteins involved in erythropoiesis, glucose transport, angiogenesis, glycolytic metabolism, reactive oxygen species (ROS) handling, cell proliferation and survival, among others. The overall regulation of the expression of HIF-dependent genes depends on the severity, duration, and location of hypoxia. In the present review, common CV diseases were selected to illustrate that HIFs, and proteins derived directly or indirectly from their stabilization and activation, are related to the development and perpetuation of hypoxia in these pathologies. We further classify CV diseases into acute and chronic hypoxic states to better understand the temporal relevance of HIFs in the pathogenesis, disease progression and clinical outcomes of these diseases. We conclude that HIFs and their derived factors are fundamental in the genesis and progression of CV diseases. Understanding these mechanisms will lead to more effective treatment strategies leading to reduced morbidity and mortality.

Non-high-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio serve as a predictor for coronary collateral circulation in chronic total occlusive patients

Objective

The present study investigated the potential correlation between non-high-density lipoprotein cholesterol/high-density lipoprotein cholesterol ratio (non-HDL-C/HDL) and the formation of coronary collateral circulation (CCC) in coronary artery disease cases with chronic total occlusive (CTO) lesions.

Methods

Two experienced cardiologists identified and selected patients with CTO lesions for retrospective analysis. The 353 patients were divided into a CCC poor formation group (Rentrop 0–1 grade, n = 209) and a CCC good formation group (Rentrop 2–3 grade, n = 144) based on the Cohen-Rentrop standard. A comparison of non-HDL-C/HDL ratios between the two groups was performed. The Spearman test was used to obtain the correlation between the cholesterol ratio and Rentrop grade. Independent predictors of CCC were analyzed using logistic regression. Receiver operating characteristic (ROC) curve analysis was also performed to quantify the predictive value of research indicator.

Results

The non-HDL-C/HDL ratio in the CCC poor formation group was elevated markedly compared to the CCC good formation group [( 3.86 ± 1.40) vs ( 3.31 ± 1.22), P = 0.000]. The Spearman test results indicated that non-HDL-C/HDL negatively correlated with Rentrop grade (r = − 0.115, P = 0.030). Multivariate logistic regression analysis showed that non-HDL-C/HDL ratio was an independent predictor of CCC formation (OR = 1.195, 95%CI = 1.020–1.400, P = 0.027). The area under the curve of ROC for detecting CCC poor formation was 0.611 (95% CI: 0.551–0.671, P = 0.000) with an optimal cut-off value of 2.77.

Conclusion

Non-HDL-C/HDL negatively correlated with the formation of CCC and served as an independent predictor of CCC formation, which may be used as a biomarker for the evaluation of CCC.

N-terminal pro-brain natriuretic peptide and coronary collateral formation in patients undergoing primary percutaneous coronary intervention

There is insufficient information on the relationship between the N-terminal pro-brain natriuretic peptide (NT-proBNP) level and collateral circulation (CC) formation after primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction. We analyzed 857 patients who underwent primary PCI. The serum NT-proBNP levels were measured on the day of admission, and the CC was scored according to Rentrop’s classification. Log-transformed NT-proBNP levels were significantly higher in patients with good CC compared to those with poor CC (6.13 ± 2.01 pg/mL versus 5.48 ± 1.97 pg/mL, p < 0.001). The optimum cutoff value of log NT-proBNP for predicting CC was 6.04 pg/mL. Log NT-proBNP ≥ 6.04 pg/mL (odds ratio 2.23; 95% confidence interval 1.51–3.30; p < 0.001) was an independent predictor of good CC. CC development was higher in patients with a pre-TIMI flow of 0 or 1 than those with a pre-TIMI flow of 2 or 3 (22.6% versus 8.8%, p = 0.001). The incidence of left ventricular (LV) dysfunction (< 50%) was greater in patients with a pre-TIMI flow of 0 or 1 (49.8% versus 35.5%, p < 0.001). The release of NT-proBNP was greater in patients with LV dysfunction (34.3% versus 15.6%, p < 0.001). The incidence of good CC was greater in patients with log NT-proBNP levels ≥ 6.04 pg/ml (16.8% versus 26.2%, p = 0.003). The association between NT-proBNP and collateral formation was not influenced by pre-TIMI flow and LV function. NT-proBNP appears to reflect the degree of collateral formation in the early phase of STEMI and might have a new role as a useful surrogate biomarker for collateral formation in patients undergoing primary PCI.

Systemic immune inflammation index: a novel predictor for coronary collateral circulation

AIM

Recently, a new inflammatory and prognostic marker has emerged called as Systemic Immune Inflammation Index (SII). In the current study, we searched the relation between SII and Coronary Collateral Circulation (CCC) formation in stable Coronary Artery Disease (CAD).

MATERIALS & METHODS

449 patients with stable CAD who underwent coronary angiography and documented coronary stenosis of 95% or more in at least one major coronary vessel were included in the study. The study patients were divided into two groups according to the Rentrop score as well CCC (Rentrop 2-3) and bad CCC (Rentrop 0-1). Blood samples for SII and other laboratory parameters were gathered from all the patients on admission. The SII score was formulized as platelet × neutrophil/lymphocyte counts.

RESULTS

Patients, who had developed bad CCC had a higher C-reactive protein (CRP), neutrophil/lymphocyte ratio (NLR), platelets/lymphocyte ratio (PLR) and SII levels compared to those who had developed well CCC (p < 0.001, for all). Multivariate logistic regression analysis showed that high levels of SII was an independent predictor of bad CCC (OR: 1.005, 95% confidence interval (CI): 1.003-1.006, p < 0.001) together with dyslipidemia, high levels of CRP and NLR. In Receiver Operator Characteristic curve (ROC) analysis, the optimal cutoff value of SII to predict poor CCC was found to be 729.8, with 78.4% sensitivity and 74.6% specificity (area under ROC curve = 0.833 (95% CI: 0.777-0.889, p < 0.001).

CONCLUSION

We have demonstrated that SII, a novel cardiovascular risk marker, might be used as one of the independent predictors of CCC development.

Relationship Between C-Reactive Protein to Albumin Ratio and Coronary Collateral Circulation in Patients With Stable Coronary Artery Disease

We investigated the relationship between the C-reactive protein (CRP) to albumin ratio (CAR) and coronary collateral circulation (CCC) in stable coronary artery disease (CAD). Patients with stable CAD (n = 354) who underwent coronary angiography for suspected CAD and had a total occlusion ≥1 major coronary artery were included in the study. The participants were divided into 2 groups according to the Rentrop score as satisfactory CCC (Rentrop 2-3) and poor CCC (Rentrop 0-1). Patients who had poor CCC had a higher CRP, neutrophil/lymphocyte ratio (NLR), and CAR levels compared with those who had satisfactory CCC (P < .001, P = .046, P < .001, respectively). The CAR (odds ratio: 3.522, 95% CI: 2.515-4.932, P < .001), CRP, NLR, and diabetes mellitus were independent predictors of poor CCC. In receiver operator characteristic curve (ROC) analysis, the optimal cutoff value of CAR to predict poor CCC was 1.27 (area under ROC curve = 0.735 [95% CI: 0.667-0.803], P < .001). A raised CAR may be an independent predictor of poor CCC.

Coronary Collateral Flow Index Is Correlated With the Palmar Collateral Flow Index: Indicating Systemic Collateral Coherence in Individual Patients-Brief Report

[Figure: see text].

Cholesterol Efflux and Collateral Circulation in Chronic Total Coronary Occlusion: Effect-Circ Study

Background

The mechanism through which high‐density lipoprotein (HDL) induces cardioprotection is not completely understood. We evaluated the correlation between cholesterol efflux capacity (CEC), a functional parameter of HDL, and coronary collateral circulation (CCC). We additionally investigated whether A1BP (apoA1‐binding protein) concentration correlates with CEC and CCC.

Methods and Results

In this case‐control study, clinical and angiographic data were collected from 226 patients (mean age, 58 years; male, 72%) with chronic total coronary occlusion. CEC was assessed using a radioisotope and J774 cells, and human A1BP concentration was measured using enzyme‐linked immunosorbent assay. Differences between the good and poor CCC groups were compared, and associations between CEC, A1BP, and other variables were evaluated. Predictors of CCC were identified by multivariable logistic regression analysis. The CEC was higher in the good than in the poor CCC group (22.0±4.6% versus 20.2±4.7%; P=0.009). In multivariable analyses including age, sex, HDL‐cholesterol levels, age (odds ratio [OR], 0.96; P=0.003), and CEC (OR, 1.10; P=0.004) were identified as the independent predictors of good CCC. These relationships remained significant after additional adjustment for diabetes mellitus, acute coronary syndrome, and Gensini score. The A1BP levels were not significantly correlated with CCC (300 pg/mL and 283 pg/mL in the good CCC and poor CCC groups, respectively, P=0.25) or CEC.

Conclusions

The relationship between higher CEC and good CCC indicates that well‐functioning HDL may contribute to CCC and may be cardioprotective; this suggests that a specific function of HDL can have biological and clinical consequences.

The Effects of Preoperative Coronary Collateral Circulation on Cardiac-Related Events after Coronary Artery Bypass Graft Surgery

Introduction

This study aimed to evaluate the effects of coronary collateral circulation (CCC) in patients who had undergone coronary artery bypass grafting (CABG).

Methods

A total of 127 patients who had undergone CABG (2011-2013) were enrolled into this study and follow-up was obtained by phone contact. Patients were categorized into two groups according to preoperative CCC using the Rentrop method. Percutaneous coronary intervention (PCI), recurrent myocardial infarction (MI), stroke, heart failure (HF), and mortality rates were compared between groups. Clinical outcome was defined as combined end point including death, PCI, recurrent MI, stroke, and HF.

Results

Sixty-two of 127 patients had poor CCC and 65 had good CCC. There were no differences in terms of PCI, recurrent MI, and HF between the groups. Stroke (seven of 62 [11.3%] and one of 65 [1.5%], P=0.026) and mortality (19 of 62 [30.6%] and 10 of 65 [15.4%], P=0.033) rates were significantly higher in poor CCC group than in good CCC group. In Kaplan-Meier analysis, survival time was not statistically different between the groups. Presence of poor CCC resulted in a significantly higher combined end point incidence (P=0.011).

Conclusion

Stroke, mortality rates, and combined end point incidence were significantly higher in poor CCC patients than in the good CCC group.

Long-term prognosis of chronic total occlusion treated by successful percutaneous coronary intervention in patients with or without diabetes mellitus: a systematic review and meta-analysis

Background

Diabetes mellitus (DM) is highly prevalent among patients undergoing percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). Therefore, the purpose of our study was to investigate the clinical outcomes of CTO-PCI in patients with or without DM.

Methods

All relevant articles published in electronic databases (PubMed, Embase, and the Cochrane Library) from inception to August 7, 2020 were identified with a comprehensive literature search. Additionally, we defined major adverse cardiac events (MACEs) as the primary endpoint and used risk ratios (RRs) with 95% confidence intervals (CIs) to express the pooled effects in this meta-analysis.

Results

Eleven studies consisting of 4238 DM patients and 5609 non-DM patients were included in our meta-analysis. For DM patients, successful CTO-PCI was associated with a significantly lower risk of MACEs (RR = 0.67, 95% CI 0.55–0.82, p = 0.0001), all-cause death (RR = 0.46, 95% CI 0.38–0.56, p < 0.00001), and cardiac death (RR = 0.35, 95% CI 0.26–0.48, p < 0.00001) than CTO-medical treatment (MT) alone; however, this does not apply to non-DM patients. Subsequently, the subgroup analysis also obtained consistent conclusions. In addition, our study also revealed that non-DM patients may suffer less risk from MACEs (RR = 1.26, 95% CI 1.02–1.56, p = 0.03) than DM patients after successful CTO-PCI, especially in the subgroup with a follow-up period of less than 3 years (RR = 1.43, 95% CI 1.22–1.67, p < 0.0001).

Conclusions

Compared with CTO-MT alone, successful CTO-PCI was found to be related to a better long-term prognosis in DM patients but not in non-DM patients. However, compared with non-DM patients, the risk of MACEs may be higher in DM patients after successful CTO-PCI in the drug-eluting stent era, especially during a follow-up period shorter than 3 years.

A preoperative modified Allen test result may be associated with long term mortality after hemodialysis access construction

BACKGROUND

The modified Allen test (MAT) is a simple bedside method determining collateral hand circulation prior to hemodialysis (HD) access surgery. Hand ischemia as reflected by low systolic finger pressures (P_dig) is associated with high mortality rates in severe kidney disease (CKD) patients. Aim of the present study was to assess a possible relation between absolute finger pressure drop (∂P_dig) during a preoperative MAT and mortality after a first HD access construction.

METHODS

P_dig (systolic pressure, mmHg) was measured using digital plethysmography following compression of radial and ulnar arteries in CKD patients just before access surgery between January 2009 and December 2018 in one center. The greatest ∂P_dig of both index fingers was used for analysis. Cardiovascular and overall mortality were assessed during the following 4 years using the ERA-EDTA classification system (codes 11, 14-16, 18, 22-26, 29). Cox regression analysis determined possible associations between ∂P_dig and mortality.

RESULTS

Complete data sets were available in 108 patients (male n = 71; age 70 years ±12; mean follow up (FU) 1.6 years ±0.1; FU index 99% ±1). Median ∂P_dig was 31 mmHg (range 0-167 mmHg). Patients having cardiovascular disease (CV+) demonstrated higher ∂P_dig values (CV+ 44 ± 5 mmHg vs CV- 29 ± 3 mmHg, p = 0.012). A total of 26 patients (24%) died during FU (CV+ death, n = 16; 62%). For each 10 mmHg ∂P_dig increase, overall mortality increased by 10%, and CV+ mortality by 15% (overall mortality: HR 1.10 [1.01-1.22], p = 0.048; CV+ mortality: 1.15 [1.03-1.29], p = 0.017). Following correction for age, ∂P_dig remained associated with CV+ mortality (HR 1.13 [1.00-1.26], p = 0.043).

CONCLUSIONS

A large drop in systolic finger pressure during a preoperative MAT is related to mortality after primary HD access surgery. The role of this potential novel risk parameter requires confirmation in a larger population.

Effect of permanent right internal mammary artery occlusion on right coronary artery supply: A randomized placebo-controlled clinical trial

Natural, nonsurgical internal mammary artery (IMA) bypasses to the coronary circulation have been shown to function as extracardiac sources of myocardial blood supply. The goal of this randomized, placebo-controlled, double-blind trial was to test the efficacy of permanent right IMA (RIMA) device occlusion on right coronary artery (RCA) occlusive blood supply and on clinical and electrocardiographic (ECG) signs of myocardial ischemia.

METHODS

This was a prospective superiority trial in 100 patients with chronic coronary artery disease randomly allocated (1:1) to RIMA vascular device occlusion (verum group) or to RIMA sham procedure (placebo group). The primary study end point was RCA collateral flow index (CFI) as obtained during a 1-minute ostial RCA balloon occlusion at baseline before and at follow-up examination 6 weeks after the trial intervention. CFI is the ratio between simultaneous mean coronary occlusive divided by mean aortic pressure both subtracted by central venous pressure. Simultaneously obtained secondary study end points were the registration of angina pectoris and quantitative intracoronary ECG ST-segment shift.

RESULTS

CFI change during the follow-up period was +0.036 ± 0.068 in the verum group and -0.021 ± 0.097 in the placebo group (P = .0011). Angina pectoris during the same RCA balloon occlusions had disappeared at follow-up in 14/49 patients of the verum group and in 4/49 patients of the placebo group (P = .0091). Simultaneous intracoronary ECG ST-segment shift change revealed diminished myocardial ischemia at follow-up in the verum group and more severe ischemia in the placebo group.

CONCLUSIONS

Permanent RIMA device occlusion augments RCA supply to the effect of diminishing clinical and electrocardiographic signs of myocardial ischemia during a brief controlled coronary occlusion.

Association of fibrinogen/albumin ratio and coronary collateral circulation in stable coronary artery disease patients

Aim: To investigate whether fibrinogen/albumin ratio (FAR) has an association with the coronary collateral circulation (CCC) in patients with stable coronary artery disease. Materials & methods: A total of 391 patients with stable coronary artery disease who underwent coronary angiography were included. The patients were divided into two groups according to the Rentrop score. Results: The poorly developed CCC group had a significantly higher FAR level compared with the well-developed CCC group (p < 0.001). In the multivariate analysis, the FAR (odds ratio: 1.700; 95% CI: 1.420-2.036; p < 0.001) was an independent predictor of poorly developed CCC. Conclusion: FAR can be used as one of the independent predictors of CCC formation.

Prognostic impact of collaterals in patients with a coronary chronic total occlusion: A meta-analysis of over 3,000 patients

OBJECTIVES

To assess the prognostic implications of the degree of coronary collaterals on outcomes in patients with a CTO.

BACKGROUND

Coronary chronic total occlusions (CTO) are identified frequently in patients undergoing coronary angiography and have been associated with poorer prognosis. Whether the degree of coronary collaterals, the hallmark of CTOs impacts prognosis, is unknown.

METHODS

A search of EMBASE, MEDLINE, and Cochrane Library was conducted to identify studies reporting on coronary collaterals and risk of all-cause mortality, acute myocardial infarction (AMI) and successful percutaneous coronary intervention (PCI). Patients with Rentrop grade 0 or 1 collaterals were defined as poor collaterals, while Rentrop grade 2 or 3 were defined as robust collaterals.

RESULTS

Twelve studies with a total of 3,369 were included. Patients with robust collaterals did not have lower rates of AMI (OR: 0.89, 95%CI: 0.39-2.04) or lower rates of all-cause mortality (OR: 0.81, 95% CI: 0.42-1.58), however were more likely to have successful PCI (OR: 4.04, 95%CI: 1.10-14.85).

CONCLUSION

The presence of robust collaterals is not associated with lower rates of AMI or mortality, but does increase the likelihood of successful CTO PCI. These results have importance implications with respect to the indications for CTO PCI as well as selecting appropriate patients to undergo the procedure.

Coronary Microvascular Dysfunction

Many patients with chest pain undergoing coronary angiography do not show significant obstructive coronary lesions. A substantial proportion of these patients have abnormalities in the function and structure of coronary microcirculation due to endothelial and smooth muscle cell dysfunction. The coronary microcirculation has a fundamental role in the regulation of coronary blood flow in response to cardiac oxygen requirements. Impairment of this mechanism, defined as coronary microvascular dysfunction (CMD), carries an increased risk of adverse cardiovascular clinical outcomes. Coronary endothelial dysfunction accounts for approximately two-thirds of clinical conditions presenting with symptoms and signs of myocardial ischemia without obstructive coronary disease, termed "ischemia with non-obstructive coronary artery disease" (INOCA) and for a small proportion of "myocardial infarction with non-obstructive coronary artery disease" (MINOCA). More frequently, the clinical presentation of INOCA is microvascular angina due to CMD, while some patients present vasospastic angina due to epicardial spasm, and mixed epicardial and microvascular forms. CMD may be associated with focal and diffuse epicardial coronary atherosclerosis, which may reinforce each other. Both INOCA and MINOCA are more common in females. Clinical classification of CMD includes the association with conditions in which atherosclerosis has limited relevance, with non-obstructive atherosclerosis, and with obstructive atherosclerosis. Several studies already exist which support the evidence that CMD is part of systemic microvascular disease involving multiple organs, such as brain and kidney. Moreover, CMD is strongly associated with the development of heart failure with preserved ejection fraction (HFpEF), diabetes, hypertensive heart disease, and also chronic inflammatory and autoimmune diseases. Since coronary microcirculation is not visible on invasive angiography or computed tomographic coronary angiography (CTCA), the diagnosis of CMD is usually based on functional assessment of microcirculation, which can be performed by both invasive and non-invasive methods, including the assessment of delayed flow of contrast during angiography, measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), evaluation of angina induced by intracoronary acetylcholine infusion, and assessment of myocardial perfusion by positron emission tomography (PET) and magnetic resonance (CMR).

Amelioration of ischemic cardiomyopathy in patients using physiological ischemic training

BACKGROUND

This study aimed to observe the effect and potential mechanism of physiological ischemic training (PIT) in patients with ischemic cardiomyopathy.

METHODS

A total of 165 patients with ischemic cardiomyopathy were randomly selected by the convenience sampling method and were divided into the control and experimental groups. The control group received conventional drug treatment, while the experimental group received additional PIT. All patients were followed up for 6 months and renin-angiotensin-aldosterone system (RAS) activity parameters and myocardial remodeling indicators were recorded.

RESULTS

After the 6‑month intervention, cardiac function indicators in the two groups were significantly improved compared with before intervention (all P < 0.01), but the experimental group showed significantly more improvement compared with the control group (all P < 0.01). Similarly, RAS activity parameters and myocardial remodeling indicators of the two groups were significantly reduced after intervention compared with before intervention (all P < 0.01). However, the experimental group showed significantly lower myocardial remodeling indicators than the control group (all P < 0.01). Vascular endothelial growth factor (VEGF) and nitric oxide (NO) concentrations in peripheral blood in the experimental group were significantly increased after intervention compared with before intervention (both P < 0.01).

CONCLUSIONS

PIT can be applied in patients with ischemic cardiomyopathy on the basis of the original standardized drug treatment. PIT ameliorates cardiac blood flow reserve by increasing VEGF and NO concentrations in the peripheral blood, as well as by inhibiting the RAS system and myocardial remodeling. This ultimately improves the patient's cardiac function to a greater extent.