The Human Coronary Collateral Circulation, Its Extracardiac Anastomoses and Their Therapeutic Promotion

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.

Comprehensive Strategies for Metabolic Syndrome: How Nutrition, Dietary Polyphenols, Physical Activity, and Lifestyle Modifications Address Diabesity, Cardiovascular Diseases, and Neurodegenerative Conditions

Several hallmarks of metabolic syndrome, such as dysregulation in the glucose and lipid metabolism, endothelial dysfunction, insulin resistance, low-to-medium systemic inflammation, and intestinal microbiota dysbiosis, represent a pathological bridge between metabolic syndrome and diabesity, cardiovascular, and neurodegenerative disorders. This review aims to highlight some therapeutic strategies against metabolic syndrome involving integrative approaches to improve lifestyle and daily diet. The beneficial effects of foods containing antioxidant polyphenols, intestinal microbiota control, and physical activity were also considered. We comprehensively examined a large body of published articles involving basic, animal, and human studie, as well as recent guidelines. As a result, dietary polyphenols from natural plant-based antioxidants and adherence to the Mediterranean diet, along with physical exercise, are promising complementary therapies to delay or prevent the onset of metabolic syndrome and counteract diabesity and cardiovascular diseases, as well as to protect against neurodegenerative disorders and cognitive decline. Modulation of the intestinal microbiota reduces the risks associated with MS, improves diabetes and cardiovascular diseases (CVD), and exerts neuroprotective action. Despite several studies, the estimation of dietary polyphenol intake is inconclusive and requires further evidence. Lifestyle interventions involving physical activity and reduced calorie intake can improve metabolic outcomes.

The comparison of adipose-derived stromal cells (ADSCs) delivery method in a murine model of hindlimb ischemia

BACKGROUND

Adipose-derived stromal cells (ADSCs) demonstrate ability to promote tissue healing and down-regulate excessive inflammation. ADSCs have been used to treat critical limb ischemia in preclinical and clinical trials, but still, there is little known about their optimal delivery strategy. To date, no direct analysis of different methods of ADSCs delivery has been performed in the hindlimb ischemia model. Therefore, in this study we focused on the therapeutic efficacy of different ADSCs delivery methods in a murine model of hindlimb ischemia.

METHODS

For the hADSCs isolation, we used the subcutaneous adipose tissue collected during the surgery. The murine hindlimb ischemia was used as a model. The unilateral femoral artery ligation was performed on 10-12-week-old male C57BL/6. ADSCs were delivered directly into ischemic muscle, into the contralateral muscle or intravenously. 7 and 14 days after the surgery, the gastrocnemius and quadriceps muscles were collected for the immunohistochemical analysis. The results were analyzed with relevant tests using the Statistica software.

RESULTS

Our research revealed that muscle regeneration, angiogenesis, arteriogenesis and macrophage infiltration in murine model of hindlimb ischemia differ depending on ADSCs delivery method. We have demonstrated that intramuscular method (directly into ischemic limb) of ADSCs delivery is more efficient in functional recovery after critical limb ischemia than intravenous or contralateral route.

CONCLUSIONS

We have noticed that injection of ADSCs directly into ischemic limb is the optimal delivery strategy because it increases: (1) muscle fiber regeneration, (2) the number of capillaries and (3) the influx of macrophages F4/80+/CD206+.

Elevated uric acid/albumin ratio as a predictor of poor coronary collateral circulation development in patients with non-ST segment elevation myocardial infarction

BACKGROUND

Uric acid/albumin ratio (UAR) is a novel composite biomarker with superior predictive value for cardiovascular disease.

OBJECTIVE

To investigate the relationship between UAR and coronary collateral circulation (CCC) in patients with non-ST segment elevation myocardial infarction (NSTEMI).

METHODS

A total of 205 NSTEMI patients who underwent coronary arteriography with at least one major coronary stenosis, 95% were included. Patients were divided into two groups according to CCC development: poorly-developed CCC group (Rentrop 0-1) and well-developed CCC (Rentrop 2-3). Univariate analysis and logistic regression analysis were utilized to investigate the factors influencing adverse CCC formation in NSTEMI patients. The receiver operating characteristic (ROC) curve was plotted to evaluate the predictive value of UAR, C-reactive protein (CRP), uric acid, and albumin for patients with poorly developed CCC, and the area under the curve (AUC) was compared.

RESULTS

The UAR values of NSTEMI patients were significantly higher in the poorly developed CCC group than those in the well-developed CCC group (10.19 [8.80-11.74] vs. 7.79 [6.28-9.55], p < .001). In the multiple logistic regression tests, UAR (odds ratio [OR]: 1.365, 95% confidence interval [CI]: 1.195-1.560, p < .001), CRP (OR: 1.149, 95% CI: 1.072-1.231, p < .001), and diabetes (OR: 2.924, 95% CI: 1.444-5.920, p = .003) were independent predictors of poorly developed CCC. The ROC curve analysis showed that the optimal cut-off value of UAR was 8.78 in predicting poorly developed CCC with a sensitivity of 76.8% and specificity of 62.4%, with the AUC of 0.737 (95% Cl: 0.668-0.805, p < .001).

CONCLUSION

Elevated UAR may be an independent and effective biomarker for predicting poorly-developed CCC development in NSTEMI patients.

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.

Refractory angina pectoris: a 20-year (2003-2022) bibliometric analysis

Background

The increasing number of patients with refractory angina pectoris, combined with the aging population and improved survival rates among coronary heart disease patients, presents a significant challenge in contemporary cardiovascular medicine. The treatment of refractory angina has been an ongoing area of exploration, yet a comprehensive analysis of the existing literature on this topic is currently lacking. Therefore, this study aims to provide the first bibliometric analysis of publications related to refractory angina.

Methods

A systematic search was conducted in the Web of Science database to identify articles related to refractory angina published between 2003 and 2022. The inclusion criteria were limited to articles and reviews written in English. CiteSpace software was utilized to conduct a collaborative network analysis of countries/regions, institutions and authors, co-occurrence analysis of keywords, and co-citation analysis of authors and references.

Results

A total of 1,386 publications were identified, with an annual publication volume exhibiting fluctuation over time. American and European countries and institutions demonstrated a leading position in terms of research output. Henry TD emerged as the most prolific researcher in the field, while Mannheimer C received the highest number of citations. The primary research hotspot within this field focused on the treatment of refractory angina, with recent emphasis on emerging treatments such as stem cell therapy and the coronary sinus reducer. A significant number of clinical trials have been conducted, with a continuous focus on patient benefits, quality of life, and survival prognosis.

Conclusion

Significant progress has been made in the field of refractory angina pectoris in recent years. Novel treatment methods, including spinal cord stimulation, enhanced external counterpulsation, stem cell therapy, and the coronary sinus reducer, hold promising therapeutic prospects. However, further high-quality evidence-based research is essential to support these emerging interventions. Additionally, the development of comprehensive evidence-based guidelines for refractory angina treatment is crucial. Such guidelines would provide clinicians with a framework to navigate the complexities of treatment choices and optimize patient care in this challenging condition.

Coronary steal: how many thieves are out there?

The colorful term "coronary steal" arose in 1967 to parallel "subclavian steal" coined in an anonymous 1961 editorial. In both instances, the word "steal" described flow reversal in the setting of an interconnected but abnormal vascular network-in one case a left subclavian stenosis proximal to the origin of the vertebral artery and in the other case a coronary fistula. Over time, the term has morphed to include a larger set of pathophysiology without explicit flow reversal but rather with a decrease in stress flow due to other mechanisms. This review aims to shed light on this phenomenon from a clinical and a pathophysiological perspective, detailing the anatomical and physiological conditions that allow so-called steal to appear and offering treatment options for six distinct scenarios.

Hyperinsulinemia Impaired Coronary Collateral Circulation in Patients with Chronic Total Coronary Occlusion

Background and Objectives

Hyperinsulinemia impaired cardiovascular system and endothelial function in the population. The purpose of this study was to explore the relationship between hyperinsulinemia and coronary collateral circulation in patients with chronic total coronary occlusion.

Methods

Patients with stable angina and at least one total coronary occlusion were enrolled in this study. Collateral grade was determined according to Rentrop's classification. Patients were divided into a good coronary collateral circulation (CCC) group (grade 2 or 3 collateral vessels, n = 223) and a poor CCC group (grade 0 or 1 collateral vessels, n = 115). Fasting insulin level (FINS) and fasting glucose level (FBS) were measured. Endothelial function evaluated by flow-mediated dilation (FMD).

Results

Serum FINS level was significantly increased in the poor CCC group (P < 0.01). Patients in the poor CCC group had higher levels of FBS, HbA1C, and homeostasis model assessment for insulin resistance (HOMA-IR) than patients in the good CCC group. The poor CCC group also had lower levels of FMD, lower LVEF and higher syntax scores than the good CCC group. Hyperinsulinemia (T3, FINS ≥15.22 μIU/mL) increased OR for the incidence of the poor CCC group (OR 2.419, 95% CI 1.780-3.287) in multivariate analysis. Multivariate logistic regression also revealed that diabetes, HbA1c, HOMA-IR, HDL-C and Syntax score were independent predictors of poor CCC (all P < 0.05).

Conclusion

Hyperinsulinemia is a valuable predictor of poor collateral formation in patients with chronic total coronary occlusion.

The Relationship Between Coronary Collateral Circulation and Serum Adropin Levels

Objective Coronary collateral circulation (CCC) are vascular structures that limit the infarct area, protect left ventricular function, and reduce the frequency of arrhythmia and mortality during myocardial ischemia and infarction. In this study, we examined the relationship between the development of CCC and serum adropin levels, which has been shown in previous studies to regulate endothelial functions and increase endothelial nitric oxide synthesis, in patients with acute myocardial infarction. Methods This study included 41 patients with insufficient CCC and 43 patients with well-developed CCC who were hospitalized for acute myocardial infarction and underwent coronary angiography. The Cohen-Rentrop classification was used to grade the CCC. The patients were divided into two groups according to Rentrop grades: those with a 0-1 stage were considered as insufficient and those with grades of 2-3 were considered as well-developed CCC. We took blood samples to measure the adropin levels within the first 24 hours of hospitalization. Results The mean age was 59.1±11.9 years and 62 (73.8%) were male. The right coronary artery was the most frequently target vessel (n: 51, 60.7%), and the majority of the patients presented with ST-segment elevation myocardial infarction (STEMI) (n:58, 69%). The median interval between the severe chest pain and the intervention was significantly higher in patients with well-developed CCC (p=0.042). The serum adropin levels in patients with insufficient CCC were significantly lower than in those with well-developed CCC (196.3 [131.5 - 837.0] pg/mL vs. 235.5 [171.9 - 1124.2] pg/mL, p<0.001). Logistic regression analysis revealed that the circumflex artery as the target vessel, NSTEMI (non-STEMI) as the type of myocardial infarction, and serum adropin level were the independent risk factors for the prediction of poor coronary collateral vessel formation (p<0.05). Conclusions In this study, we found that in patients with acute myocardial infarction, those with well-developed CCC had higher adropin levels.

Well-Developed Coronary Collateral Circulation Is Associated With Higher Thrombus Burden in the Setting of ST-Segment Elevation Myocardial Infarction

Background

This study investigated the relationship between coronary collateral circulation (CCC) and intracoronary thrombus burden in patients undergoing primary percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI). CCC and thrombus burden are predictive of clinical outcomes in patients with STEMI.

Methods

Patients with STEMI undergoing primary percutaneous coronary intervention were enrolled (n = 172). CCC was graded according to the Cohen–Rentrop classification. Patients were classified as insufficient (grade 0 or 1, n = 134) or well-developed (grade 2 or 3; n = 38) CCC. The Thrombolysis in Myocardial Infarction scale was used to evaluate intra-coronary thrombus burden. The low-thrombus-burden group comprised those with grades 0 to 2, and the high-thrombus-burden group comprised those with grades 3 or 4.

Results

Right coronary artery infarcts had a 13.830-fold higher chance of having well-developed CCC than did left anterior descending artery infarcts (P &lt; .001). Circumflex artery infarcts had a 7.904-fold higher chance of well-developed CCC than did left anterior descending artery infarcts (P = .016). High thrombus burden was associated with a 4.393-fold higher chance for well-developed CCC than was low thrombus burden (P = .030). Low albumin levels were related to a greater chance of having well-developed CCC (P = .046).

Conclusion

Patients with well-developed CCC have higher thrombus burden than do those with insufficient CCC. Because well-developed CCC is an indicator of more severe underlying lesions, we speculate that patients with severe lesions are more prone to experience more complicated STEMI with high thrombus burden.

Diabetic dyslipidemia impairs coronary collateral formation: An update

Coronary collateralization is substantially impaired in patients with type 2 diabetes and occlusive coronary artery disease, which leads to aggravated myocardial ischemia and a more dismal prognosis. In a diabetic setting, altered serum lipid profiles and profound glycoxidative modification of lipoprotein particles induce endothelial dysfunction, blunt endothelial progenitor cell response, and severely hamper growth and maturation of collateral vessels. The impact of dyslipidemia and lipid-lowering treatments on coronary collateral formation has become a topic of heightened interest. In this review, we summarized the association of triglyceride-based integrative indexes, hypercholesterolemia, increased Lp(a) with its glycoxidative modification, as well as quantity and quality abnormalities of high-density lipoprotein with impaired collateral formation. We also analyzed the influence of innovative lipid-modifying strategies on coronary collateral development. Therefore, clinical management of diabetic dyslipidemia should take into account of its effect on coronary collateralization in patients with occlusive coronary artery disease.

The Central Nervous System and Psychosocial Factors in Primary Microvascular Angina

Patients diagnosed with ischemia without obstructive coronary artery disease (INOCA) comprise the group of patients with primary microvascular angina (MVA). The pathophysiology underlying ischemia and angina is multifaceted. Differences in vascular tone, collateralization, environmental and psychosocial factors, pain thresholds, and cardiac innervation seem to contribute to clinical manifestations. There is evidence suggesting potential interactions between the clinical manifestations of MVA and non-cardiac conditions such as abnormal function of the central autonomic network (CAN) in the central nervous system (CNS), pain modulation pathways, and psychological, psychiatric, and social conditions. A few unconventional non-pharmacological and pharmacological techniques targeting these psychosocial conditions and modulating the CNS pathways have been proposed to improve symptoms and quality of life. Most of these unconventional approaches have shown encouraging results. However, these results are overall characterized by low levels of evidence both in observational studies and interventional trials. Awareness of the importance of microvascular dysfunction and MVA is gradually growing in the scientific community. Nonetheless, therapeutic success remains frustratingly low in clinical practice so far. This should promote basic and clinical research in this relevant cardiovascular field investigating, both pharmacological and non-pharmacological interventions. Standardization of definitions, clear pathophysiological-directed inclusion criteria, crossover design, adequate sample size, and mid-term follow-up through multicenter randomized trials are mandatory for future study in this field.

The Role of Angiogenesis and Arteriogenesisin Myocardial Infarction and Coronary Revascularization

Surgical myocardial revascularization is associated with long-term survival benefit in patients with multivessel coronary artery disease. However, the exact biological mechanisms underlying the clinical benefits of myocardial revascularization have not been elucidated yet. Angiogenesis and arteriogenesis biologically leading to vascular collateralization are considered one of the endogenous mechanisms to preserve myocardial viability during ischemia, and the presence of coronary collateralization has been regarded as one of the predictors of long-term survival in patients with coronary artery disease (CAD). Some experimental studies and indirect clinical evidence on chronic CAD confirmed an angiogenetic response induced by myocardial revascularization and suggested that revascularization procedures could constitute an angiogenetic trigger per se. In this review, the clinical and basic science evidence regarding arteriogenesis and angiogenesis in both CAD and coronary revascularization is analyzed with the aim to better elucidate their significance in the clinical arena and potential therapeutic use.

Extracardiac coronary steal induced by upper limb hyperemia: a feature of internal mammary artery arteriogenesis

Function of naturally existing internal mammary artery (IMA)-to-coronary artery anastomoses has been shown by augmented blood supply to the coronary collateral circulation in response to IMA occlusion. Theoretically, this beneficial functional connection is invertible and can be linked to coronary steal, the verification of whose hypothesis would provide alternate proof to the mentioned functional evidence. This was an observational study including 40 patients with chronic coronary syndrome, distal IMA occlusion, and upper limb hyperemia (verum group), and 40 propensity score matched controls (placebo group) without IMA occlusion or hyperemia. Primary study end point was the intergroup difference and temporal development in coronary collateral function (i.e., collateral flow index; CFI) as obtained at 30, 45, and 60 s following a proximal coronary artery balloon occlusion. CFI is the ratio between simultaneous mean coronary occlusive pressure divided by mean aortic pressure both subtracted by central venous pressure. To provoke a steal phenomenon, upper limb hyperemia was induced by upper arm blood pressure cuff deflation following a 5-min suprasystolic inflation ipsilateral to the sensor-wired coronary artery with release immediately after the first CFI measurement. Between the first and the second CFI measurement, CFI change (i.e., CFI@45s - CFI@30s) was absent in the verum group whereas there was CFI recruitment in the placebo group: 0.000 ± 0.023 and +0.009 ± 0.013, respectively; P = 0.032. Among patients with artificial distal IMA occlusion, induction of ipsilateral upper limb hyperemia provokes extracardiac coronary steal as expressed by temporarily absent collateral recruitment as it normally takes place without upper limb hyperemia.NEW & NOTEWORTHY Induction of ipsilateral upper limb hyperemia provokes extracardiac coronary steal among patients with artificial distal internal mammary artery occlusion. Coronary steal via the occluded internal mammary arteries serves as alternate proof of concept of the already existing evidence of their functional extracoronary collateral supply.

Contradictory Effect of Coronary Collateral Circulation on Regional Myocardial Perfusion That Assessed by Quantitative Myocardial Perfusion Scintigraphy

Background

Previous studies showed conflicting results about the contribution of coronary collateral circulation (CCC) to myocardial perfusion and function. The aim of this study was to investigate these contradictory problems by gated myocardial perfusion scintigraphy (gated MPS) for the first time.

Methods

The current cohort was retrospectively selected among patients who underwent gated MPS and coronary angiography within 2 months. Two different groups including 96 patients were assessed by gated MPS to detect the understanding of the miscellaneous effect of CCC on myocardial perfusion. Group 1 consisted of those who had collateral arteries that were not-well-developed (Rentrop grade 0 - 1) (n = 58), while group 2 consisted of those who had collateral arteries that were well-developed (Rentrop grade 2 - 3) (n = 38).

Results

There was no statistically significant difference between groups 1 and 2 in terms of perfusion and functional parameters obtained from gated MPS. Furthermore, no statistically significant difference was found in the phase analysis parameters which is a novel technique to evaluate left ventricular synchronization. On the other hand the left ventricular mass index values were high and quite close to the statistically significant value (P = 0.059) in group 2.

Conclusions

The current results that obtained by using the gated MPS technique for the first time in the evaluation of CCC showed that the well-developed collateral circulation has a positive effect on myocardial perfusion and function, but this effect was not statistically significant. Results need to be supported by large scale of patients’ size.

Decreased inspired oxygen stimulates de novo formation of coronary collaterals in adult heart

RATIONALE

Collateral vessels lessen myocardial ischemia when acute or chronic coronary obstruction occurs. It has long been assumed that although native (pre-existing) collaterals enlarge in obstructive disease, new collaterals do not form in the adult. However, the latter was recently shown to occur after coronary artery ligation. Understanding the signals that drive this process is challenged by the difficulty in studying collateral vessels directly and the complex milieu of signaling pathways, including cell death, induced by ligation. Herein we show that hypoxemia alone is capable of inducing collateral vessels to form and that the novel gene Rabep2 is required.

OBJECTIVE

Hypoxia stimulates angiogenesis during embryonic development and in pathological states. We hypothesized that hypoxia also stimulates collateral formation in adult heart by a process that involves RABEP2, a recently identified protein required for formation of collateral vessels during development.

METHODS AND RESULTS

Exposure of mice to reduced FiO2 induced collateral formation that resulted in smaller infarctions following LAD ligation and that reversed on return to normoxia. Deletion of Rabep2 or knockdown of Vegfa inhibited formation. Hypoxia upregulated Rabep2, Vegfa and Vegfr2 in heart and brain microvascular endothelial cells (HBMVECs). Knockdown of Rabep2 impaired migration of HBMVECs. In contrast to systemic hypoxia, deletion of Rabep2 did not affect collateral formation induced by ischemic injury caused by LAD ligation.

CONCLUSIONS

Hypoxia induced formation of coronary collaterals by a process that required VEGFA and RABEP2, proteins also required for collateral formation during development. Knockdown of Rabep2 impaired cell migration, providing one potential mechanism for RABEP2's role in collateral formation. This appears specific to hypoxia, since formation after acute ischemic injury was unaffected in Rabep2-/- mice. These findings provide a novel model for studying coronary collateral formation, and demonstrate that hypoxia alone can induce new collaterals to form in adult heart.

A Review of Mechanisms on the Beneficial Effect of Exercise on Atherosclerosis

Cardiovascular disease has affected a large percentage of the world, and as a result, we have had major advancements in pharmacological and procedural intervention of this disease. With the increased burden of rising healthcare costs, alternative treatment with exercise has shown to be much more cost effective and just as beneficial to patients compared to pharmacological and procedural treatment. We highlight some of the major mechanisms behind the beneficial effect of exercise on atherosclerosis and hope to encourage patients and providers to attempt to adopt this form of treatment that has not only shown to be beneficial to heart disease, but diseases such as diabetes and obesity as well.

Incomplete protective effect of coronary collateral circulation for acute myocardial infarction patients

The short-term and long-term effects of coronary collateral circulation (CCC) discovered after acute myocardial infarction (AMI) are still debatable. This retrospective cohort study aimed to explore the clinical significance of CCC for AMI patients.A consecutive series of 323 AMI patients with CCC and 1339 AMI subjects without CCC were enrolled, most of them received percutaneous coronary intervention after AMI. Comparisons between CCC subjects and non-CCC population and between CCC sub-groups were applied regarded to basic clinical characteristics, stenosis extent indicated by Gensini score, myocardial infarction size estimated by peak concentration of troponin I (TnI), and left ventricular function evaluated by peak value of N-terminal pro-brain natriuretic peptide (NT-proBNP). Multiple linear regressions for NT-proBNP and TnI, and Kaplan-Meier curves for 5-years' main cardiovascular event (MACE) were also analyzed.CCC might provide incomplete protection by preventing excessive myocardial infarction but not a poorer heart function during AMI and CCC had no obvious protective effect on 5-years' MACE for AMI patients. More attentions should be paid to heart function for CCC patients during AMI.

From Increased Fluid Shear Stress to Natural Bypass Growth

This Special Issue enqueues a series of publications dealing with arteriogenesis, which is the growth of a natural bypass from pre-existing arteriolar connections, as defined by Wolfgang Schaper, Werner Risau and Ramon Munoz-Chapuli in the late nineties of the last century [...].

Invasive Assessment of the Myocardial Microcirculation during Beating Heart Coronary Artery Bypass Grafting

Coronary artery bypass grafting may be associated with several cardiac complications, including ischemia, acute myocardial infarction, arrhythmias, or hemodynamic instability. Accumulating evidence suggests that well-developed coronary collateral circulation may protect against adverse effects, including myocardial ischemia. Assessment of myocardial microvascular perfusion is, therefore, of great clinical interest in beating heart surgery. In this paper, myocardial microvascular perfusion is continuously assessed on the beating heart using laser Doppler flowmetry in consecutive patients who underwent coronary artery bypass grafting procedures. No significant (p = 0.110) differences were found between the averaged perfusion signal (n = 42) at the baseline, during artery occlusion, or after reperfusion (732.4 ± 148.0 vs. 711.4 ± 144.1 vs. 737.0 ± 141.2, respectively). In contrast, significantly different (p < 0.001) mean perfusion signals (n = 12) were found (805.4 ± 200.1 vs. 577.2 ± 212.8 vs. 649.3 ± 220.8) in a subset of patients who presented with hemodynamic instability and myocardial ischemia. Additionally, a strong positive correlation between the plasma levels of high-sensitivity troponin I and perfusion decrease level after artery occlusion was found (r = 0.854, p < 0.001). This study argues that myocardial microvascular perfusion remains constant during coronary artery bypass grafting on the beating heart in advanced coronary artery disease. This phenomenon is most likely due to an extensive coronary collateral circulation.