Collateralization and the response to obstruction of epicardial coronary arteries

Epistaxis After Orthognathic Surgery: Literature Review and Three Case Studies

Study Design

This is a literature review with 3 case studies.

Objective

Intraoperative and postoperative bleeding are the most common complications of orthognathic surgery and have the potential to become life-threatening. The rarity of severe postoperative epistaxis has resulted in limited characterization of these cases in the literature. The purpose of this study is to 1) differentiate various presentations of epistaxis following orthognathic surgery in the literature, 2) identify management approaches, and 3) to synthesize a treatment algorithm to guide future management of postoperative epistaxis.

Methods

A literature search of PubMed was conducted and 28 cases from 17 studies were assessed.

Results

Bleeding within the first week may indicate isolated epistaxis, often resolved with local tamponade. Half of cases were attributed to pseudoaneurysm rupture (n = 14), with epistaxis onset ranging from postoperative day 6 to week 9. Angiography was used in most cases (n = 17), often as the primary imaging modality (n = 11). Nasal endoscopy is a less invasive and effective alternative to angiography with embolization. Proximal vessel ligation was used in 3 cases but is not preferred because collaterals may reconstitute flow through the defect and cause rebleeding. Repeat maxillary down-fracture with surgical exploration was described in 4 cases.

Conclusions

As outlined in our management algorithm, nasal packing and tamponade should be followed by either local electrocautery or vascular imaging. Angiography with embolization is the preferred approach to diagnosis and management, whereas surgical intervention is reserved for cases of embolization failure or unavailability.

The Syndrome of Large Healed Single Discrete Myocardial Infarct with Severe Narrowing of Only One Major Epicardial Coronary Artery and Leading to Severe Chronic Heart Failure and Orthotopic Heart Transplantation

Described herein are clinical and cardiac morphologic findings in 12 patients (age 43 to 70 years) (7 men) who underwent orthotopic heart transplantation (OHT) because of severe heart failure (HF) resulting from a single large discrete acute myocardial infarct that healed and was associated with severe narrowing of only one major epicardial coronary artery. Most myocardial infarcts are associated with severe narrowing of >1 major epicardial coronary artery and result in smaller myocardial infarcts. Another unusual feature was the total infarction of the ventricular septum in 3 of the 12 patients.

<p>Chronic Total Occlusion of the Left Main Coronary Artery in an HIV-Infected Patient</p>

Coronary artery disease (CAD) is amongst the leading causes of death in human immunodeficiency virus (HIV)-infected persons. Severe left main disease (LMD) occurs in approximately five percent of HIV-infected patients, with chronic total occlusion (CTO) of this vessel being an even rarer phenomenon. We describe a non-adherent HIV-infected patient with a left main coronary artery (LMCA) CTO that presented with heart failure with mildly reduced ejection fraction (HFrEF) and ventricular tachycardia (VT).

Lipoprotein(a) as a predictor of poor collateral circulation in patients with chronic stable coronary heart disease

As a mechanism compensating for obstructive coronary artery disease, coronary collateral circulation (CCC) has attracted cardiologists for a long time to explore its potential impact. In the present study, Chinese patients suffering from ≥95% coronary stenosis, as diagnosed by angiography, have been investigated for the correlation between CCC and lipoprotein(a) [Lp(a)] levels. A cohort of 654 patients was divided into four categories according to Rentrop grades 0, 1, 2, and 3. Lp(a) levels were divided into model 1, discretized with critical values of 33 and 66%, and model 2, discretized with a cutoff value of 30.0 mg/dL. Furthermore, we evaluated the correlation between CCC and serum Lp(a) levels. The four groups had significantly different Lp(a) levels (25.80±24.72, 18.99±17.83, 15.39±15.80, and 8.40±7.75 mg/dL; P<0.001). In model 1, concerning R0, the risk in the third Lp (a) tertile (OR=3.34, 95%CI=2.32-4.83) was greater than that in the first tertile. In model 2, concerning R0, the risk in Lp(a) >30.0 group (OR=6.77, 95%CI=4.44-10.4) was greater than that of Lp(a) <30.0 mg/dL. The worst condition of CCC can be predicted independently by Lp(a) levels. In addition to clinical usage, Lp(a) levels can also be utilized as biological markers.

Which Coronary Lesions Are More Prone to Cause Acute Myocardial Infarction?

Background

According to common belief, most myocardial infarctions (MIs) are due to the rupture of nonsevere, vulnerable plaques with < 70% obstruction. Data from recent trials challenge this belief, suggesting that the risk of coronary occlusion is, in fact, much higher after severe stenosis. The aim of this study was to investigate whether or not acute ST-elevation MIs result from high-grade stenoses by evaluating the presence of coronary collateral circulation (CCC).

Methods

We retrospectively included 207 consecutive patients who had undergone primary percutaneous coronary intervention for acute ST-elevation MI. Collateral blood flow distal to the culprit lesion was assessed by two investigators using the Rentrop scoring system.

Results

Out of the 207 patients included in the study, 153 (73.9%) had coronary collateral vessels (Rentrop 1-3). The Rentrop scores were 0, 1, 2, and 3 in 54 (26.1%), 50 (24.2%), 51 (24.6%), and 52 (25.1%) patients, respectively. Triglycerides, mean platelet volume (MPV), white cell (WBC) count, and neutrophil count were significantly lower in the group with good collateral vessels (p = 0.013, p = 0.002, p = 0.003, and p = 0.021, respectively).

Conclusion

More than 70% of the patients with acute MI had CCC with Rentrop scores of 1-3 during primary coronary angiography. This shows that most cases of acute MI in our study originated from underlying high-grade stenoses, challenging the common believe. Higher serum triglycerides levels, greater MPV, and increased WBC and neutrophil counts were independently associated with impaired development of collateral vessels.

Plasma endothelin-1 level as a predictor for poor collaterals in patients with ≥95% coronary chronic occlusion

BACKGROUND

Coronary collateral circulation (CCC) plays an important role in protecting myocardium from ischemic damage. The studies on factors which impact on CCC might be of great clinical interest. The aim of the present study was to evaluate endothelin-1 (ET-1) as a potential predictor for poor or good CCC in patients with angiography-proven ≥95% coronary occlusion.

METHODS

We screened 1038 consecutive patients with ≥95% occlusion in at least one major epicardial coronary artery detected by coronary angiography. Of these, 663 patients were classified into the poor CCC group with Rentrop 0-2 grade collateral circulation and 375 patients into the good CCC group with Rentrop 3 grade. The association of plasma ET-1 levels with collateral status was assessed.

RESULTS

We found that patients in the poor CCC group had a higher ET-1 level than those in the good CCC group (0.59±0.48 vs. 0.39±0.32pmol/L, p<0.001), and the ET-1 values increased with the descent of the Rentrop grades (p for trend<0.001). Moreover, multivariate logistic regression analysis revealed an independent association between ET-1 and collateral status (odds ratio [95% CI] for poor CCC 2.27 [1.60-3.22], p<0.001). Additionally, the association presented significance in both men (odds ratio [95% CI] for poor CCC 3.18 [2.20-4.74], p<0.001) and women (odds ratio [95% CI] for poor CCC 3.10 [1.36-7.85], p=0.011) when the sex-specific analysis was performed.

CONCLUSIONS

Plasma ET-1 level may be a useful, easily available marker for predicting the degree of CCC in patients with ≥95% coronary chronic occlusion.

C-reactive protein as a predictor for poor collateral circulation in patients with chronic stable coronary heart disease

AIM

To investigate the association between serum C-reactive protein (CRP) levels and coronary collateral circulation (CCC) in Chinese patients with angiography-proven ≥95% coronary stenosis.

METHODS

In this study, 1158 patients with angiography-proven ≥95% occlusion in ≥1 major epicardial coronary artery were enrolled, and then classified into two groups: poor CCC (Rentrop grades 0-1) and good CCC (Rentrop grades 2-3). CRP levels were grouped using the following two models: Model 1 discretized CRP group with 33.33% and 66.66% as the critical values and Model 2 with 1.0 and 3.0 mg/L as the cut off values.

RESULTS

There were significant differences in serum CRP levels between the two groups (5.76 ± 3.45 vs. 3.49 ± 2.44 mg/L, respectively; p < 0.001), and compared with the first CRP tertile, the risks of poor CCC were higher in the second and third CRP tertiles (OR 2.31, 95%CI [1.67-3.19], OR 6.25, 95%CI [4.52-8.62], respectively). The receiver operating characteristic curve analysis indicated that the optimal cutoff value of CRP to predict poor CCC was 4.21 mg/L with 59.6% sensitivity and 74.33% specificity.

CONCLUSIONS

CRP levels are an independent predictor for poor CCC and might supply a useful biomarker in clinical applications. Key messages C-reactive protein (CRP) is a non-specific inflammatory marker that is regarded as an independent risk and prognostic factor for individuals who suffer from coronary artery disease (CAD) and cardiovascular disorders. In a Chinese cohort of patients with coronary artery occlusion or stenosis of ≥95% TIMI grade 1 anterograde-flow, the relationship between CRP concentrations and angiographically visible coronary collateral (CC) was assessed. Our data indicated that elevated CRP associated with a significant impairment in CC development, and might supply a useful biomarker in clinical applications.

Study of Third Coronary Artery in Adult Human Cadaveric Hearts

INTRODUCTION

Third coronary artery (TCA) is a direct branch arising from the anterior aortic sinus (right aortic sinus) which supplies right ventricular outflow tract. It is found frequently and may be an important source for collateral coronary blood flow through a vascular anastomotic bridge (circle of Vieussens) between the right and left coronary systems.

AIM

To evaluate the gross anatomy of third coronary artery in terms of their number, origin, extent and distribution.

MATERIALS AND METHODS

After an ethical approval, 150 formalin fixed adult human cadaveric hearts were collected from Department of Anatomy, BVDU Medical College and Hospital, Sangli and Pune over the period of six years. The careful dissection was carried out to note details about third coronary artery and data was analysed using SPSS computer software.

RESULTS

The TCA was present in 32% of the heart specimens. In 42 hearts (28%) single TCA and in 6 hearts (4%) double TCA were noted. It was found to be variably distributed to conus arteriosus, anterior wall of the right ventricle, interventricular septum and the apex of the heart. TCA was larger than right coronary artery in 8 hearts and later ended at inferior border of heart. Myocardial bridge was noted over large third coronary artery in one specimen.

CONCLUSION

TCA is present frequently. It anastomoses with branches of left anterior descending artery (LADA) and contributes to apical and septal perfusion. Hence role of TCA should always be considered during diagnostic and therapeutic interventions.

The Fibrin Matrix Regulates Angiogenic Responses within the Hemostatic Microenvironment through Biochemical Control

Conceptually, premature initiation of post-wound angiogenesis could interfere with hemostasis, as it relies on fibrinolysis. The mechanisms facilitating orchestration of these events remain poorly understood, however, likely due to limitations in discerning the individual contribution of cells and extracellular matrix. Here, we designed an in vitro Hemostatic-Components-Model (HCM) to investigate the role of the fibrin matrix as protein factor-carrier, independent of its cell-scaffold function. After characterizing the proteomic profile of HCM-harvested matrix releasates, we demonstrate that the key pro-/anti-angiogenic factors, VEGF and PF4, are differentially bound by the matrix. Changing matrix fibrin mass consequently alters the balance of releasate factor concentrations, with differential effects on basic endothelial cell (EC) behaviors. While increasing mass, and releasate VEGF levels, promoted EC chemotactic migration, it progressively inhibited tube formation, a response that was dependent on PF4. These results indicate that the clot’s matrix component initially serves as biochemical anti-angiogenic barrier, suggesting that post-hemostatic angiogenesis follows fibrinolysis-mediated angiogenic disinhibition. Beyond their significance towards understanding the spatiotemporal regulation of wound healing, our findings could inform the study of other pathophysiological processes in which coagulation and angiogenesis are prominent features, such as cardiovascular and malignant disease.

Predictors of coronary collaterals in patients with non ST-elevated acute coronary syndrome: the paradox of the leukocytes

Aim of the study

Atherosclerosis represents active inflammation in which leukocytes play significant role. Coronary collateral development is a response to myocardial ischaemia. In this study we aimed to investigate the association of the leukocytes with coronary collateral development in patients with non ST-elevated acute coronary syndromes (NST-ACS).

Material and methods

A total of 251 consecutive patients were hospitalized in our hospital with a diagnosis of NST-ACS. The blood samples were collected 1-hour after admission to the hospital and peripheral leukocytes (neutrophils, monocytes and lymphocytes) were examined. All patients underwent coronary angiography. The coronary collateral vessels (CCV) are graded according to the Rentrop scoring system.

Results

Group 1 consisted of 146 patients with Rentrop 0 and Group 2 consisted of 105 patients with Rentrop 1, 2 and 3. The presence of CCV was significantly associated with neutrophil count, lymphocyte count, monocyte count and neutrophil-lymphocyte ratio (NLR). In subgroup analyses, higher NLR was significantly associated with good CCV development in patients with NST-ACS.

Conclusions

Higher neutrophil count, monocyte count and NLR and lower lymphocyte count on admission, were associated with the presence of CCV in patients with NST-ACS. High NLR may predict good collateral development in patients with NST-ACS.

Coronary collateral circulation in patients of coronary ectasia with significant coronary artery disease

Objectives

Patients with coronary ectasia (CE) usually have coexisting coronary stenosis resulting in myoischemia. Coronary collateral plays an important role in protecting myocardium from ischemia and reducing cardiovascular events. However, limited studies investigate the role of CE in coronary collaterals development.

Methods

We evaluated 1020 consecutive patients undergoing coronary angiography and 552 patients with significant coronary artery disease (SCAD), defined as diameter stenosis more than 70%, were finally analyzed. CE is defined as the ectatic diameter 1.5 times larger than adjacent reference segment. Rentrop collateral score was used to classify patients into poor (grades 0 and 1) or good (grades 2 and 3) collateral group.

Results

73 patients (13.2%) had CE lesions which were most located in the right coronary artery (53.4%). Patients with CE had a lower incidence of diabetes (43.8% vs 30.1%, p = 0.03), higher body mass index (25.4±3.5 vs 26.7±4.6, p = 0.027) and poorer coronary collateral (58.2% vs 71.2%, p = 0.040). Patients with poor collateral (n = 331) had a higher incidence of CE (15.7% vs 9.5%, p = 0.040) and fewer diseased vessels numbers (1.96±0.84 vs 2.48±0.69, p<0.001). Multivariate analysis showed diabetes (odd ratio (OR) 0.630, p = 0.026), CE (OR = 0.544, p = 0.048), and number of diseased vessels (OR = 2.488, p<0.001) were significant predictors of coronary collaterals development.

Conclusion

The presence of CE was associated with poorer coronary collateral development in patients with SCAD.

Predictor of poor coronary collaterals in elderly population with significant coronary artery disease

BACKGROUND

Coronary collateral circulation plays an important role in protecting myocardium from ischemia and reducing cardiovascular events. Advanced age might be associated with poor coronary collateral development and cardiovascular outcome. However, limited studies investigate the predictors for collateral development in the elderly population.

METHODS

The authors evaluated 950 consecutive patients undergoing coronary angiography and finally analyzed 207 patients of 65 years or more. The collateral scoring system developed by Rentrop was used to classify patients into those with poor or good collateral formation.

RESULTS

The patients with poor collateral were older age, had lower incidence of smoking, more male sex, had fewer diseased vessels and had a trend to be diabetic. Multivariate analysis showed age (odds ratio (OR) = 1.068; P = 0.019), diabetes (OR = 2.681; P = 0.003) and diseased vessels numbers (OR = 0.337; P < 0.001) were significant predictors of poor collaterals development. Furthermore, age and diabetes have a synergistic effect on poor collateral development (P = 0.041 for interaction).

CONCLUSIONS

Even in the elderly population, age and diabetes might negatively influence the coronary collaterals development.

Influence of high-density lipoprotein cholesterol on coronary collateral formation in a population with significant coronary artery disease

Background

Coronary collateral circulation plays an important role in protecting myocardium from ischemia and reducing cardiovascular events. Low High-density lipoprotein cholesterol (HDL-C) level is a strong risk factor for coronary artery disease (CAD) and is associated with poor cardiovascular outcome. It was recently reported to be associated with poor coronary collateral development in Turkish population. Hence, we investigated the influence of HDL-C on coronary collateral formation in Chinese population.

Methods

We evaluated 970 consecutive patients undergoing coronary angiography, and 501 patients with significant coronary artery disease (SCAD) were finally analyzed. The collateral scoring system developed by Rentrop was used to classify patient groups as those with poor or good collaterals.

Results

The patients with poor collaterals had fewer diseased vessels (1.97 ± 0.84 vs 2.47 ± 0.68, p < 0.001) and lower diffuse score (2.65 ± 1.63 vs 3.76 ± 1.78, p < 0.001). There was no significant difference in HDL-C and other variables between good and poor collaterals. Multivariate analysis showed only number of diseased vessels (odd ratio 0.411, p < 0.001) was a significant predictor of poor collateral development.

Conclusions

The extent of CAD severity but not HDL-C level was the most powerful predictor of coronary collateral formation in our Chinese population with SCAD.

Non-invasive imaging in coronary artery disease including anatomical and functional evaluation of ischaemia and viability assessment

Coronary artery disease has an important impact on the morbidity and mortality statistics and health economics worldwide. Diagnosis of coronary artery disease is important in risk stratification and guides further management. Invasive coronary angiography is the traditional method of imaging the coronary arteries and remains the gold standard. It detects luminal stenosis but provides little information about the vessel wall or plaques. Besides, not all anatomical lesions are functionally significant. This has lent itself to a wide variety of imaging techniques to identify and assess a flow-limiting stenosis. The approach to diagnosis of coronary artery disease is broadly based on anatomical and functional imaging. Coronary CT and MRI of coronary arteries provide an anatomical assessment of coronary stenosis. Coronary calcium score and coronary CT assess subclinical atherosclerosis by assessing the atherosclerotic plaque burden. The haemodynamic significance of a coronary artery stenosis can be assessed by stress radioisotope studies, stress echocardiography and stress MRI. The more recent literature also focuses on plaque assessment and identification of plaques that are likely to give rise to an acute coronary syndrome. There is an explosion of literature on the merits and limitations of the different imaging modalities. This review article will provide an overview of all the imaging modalities in the diagnosis of coronary artery disease.

Predictor of poor coronary collaterals in chronic kidney disease population with significant coronary artery disease

BACKGROUND

Coronary collateral circulation plays an important role to protect myocardium from ischemia, preserve myocardial contractility and reduce cardiovascular events. Chronic kidney disease (CKD) is associated with poor coronary collateral development and cardiovascular outcome. However, limited research investigates the predictors for collateral development in the CKD population.

METHODS

We evaluated 970 consecutive patients undergoing coronary angiography and 202 patients with CKD, defined as a glomerular filtration rate less than 60 ml/min/1.73 m2, were finally analyzed. The collateral scoring system developed by Rentrop was used to classify patients into poor (grades 0 and 1) or good (grades 2 and 3) collateral group.

RESULTS

The patients with poor collateral (n = 122) had a higher incidence of hypertension (82% vs 63.8%, p = 0.005), fewer diseased vessels numbers (2.1 ± 0.9 vs 2.6 ± 0.6, p < 0.001) and a trend to be diabetic (56.6% vs. 43.8%, p = 0.085) or female sex (37.7% vs. 25.0%, p = 0.067). Multivariate analysis showed hypertension (odd ratio (OR) 2.672, p = 0.006), diabetes (OR 1.956, p = 0.039) and diseased vessels numbers (OR 0.402, p < 0.001) were significant predictors of poor coronary collaterals development. Furthermore, hypertension and diabetes have a negative synergistic effect on collateral development (p = 0.004 for interaction).

CONCLUSIONS

In the CKD population hypertension and diabetes might negatively influence the coronary collaterals development.

Theoretical models for coronary vascular biomechanics: progress & challenges

A key aim of the cardiac Physiome Project is to develop theoretical models to simulate the functional behaviour of the heart under physiological and pathophysiological conditions. Heart function is critically dependent on the delivery of an adequate blood supply to the myocardium via the coronary vasculature. Key to this critical function of the coronary vasculature is system dynamics that emerge via the interactions of the numerous constituent components at a range of spatial and temporal scales. Here, we focus on several components for which theoretical approaches can be applied, including vascular structure and mechanics, blood flow and mass transport, flow regulation, angiogenesis and vascular remodelling, and vascular cellular mechanics. For each component, we summarise the current state of the art in model development, and discuss areas requiring further research. We highlight the major challenges associated with integrating the component models to develop a computational tool that can ultimately be used to simulate the responses of the coronary vascular system to changing demands and to diseases and therapies.

The association of circulating monocyte count with coronary collateral growth in patients with diabetes mellitus

The status of inflammation may affect the collateral development in patients with diabetes mellitus (DM). Monocytes were found to have an important role in collateral growth in animal studies. We aimed to investigate the possible association of circulating monocyte count with collateral development in patients with DM and severe coronary artery disease (CAD). We enrolled 134 consecutive patients with DM who had > or =95 stenosis in at least one major coronary artery and investigated the relationship between circulating monocyte count and collateral growth. When we analyzed the coronary angiograms of eligible patients, we found that 64 of them had good collateral growth and 70 had poor collateral growth according to the Cohen-Rentrop method. The monocyte count was significantly different between good and poor collateral growth groups (643 +/- 184 vs. 479 +/- 143 per mm(3), P < 0.001). In the analysis comparing the Rentrop score with the Gensini score and circulating monocyte count, we found significant correlations (r = 0.293, P = 0.001 and r = 0.455, P < 0.001, respectively). The duration of ischemic symptoms tended to be longer in the good collateral group (1.9 +/- 4.1 vs. 0.8 +/- 1.3 years, P = 0.079). The Gensini score was also correlated with the duration of myocardial ischemic symptoms (r = 0.299, P = 0.004). Multivariate analysis revealed an increased monocyte count in the good collateral group [odds ratio (OR), 5.726; 95% confidence interval (CI), 1.817-18.040, P = 0.003, the cut-off value for monocyte was defined as 550 cell/mm(3)]. The increased circulating monocyte count in diabetic patients was evidently related to good coronary collateral growth. This finding may be potentially important in clinical and basic cardiovascular medicine.

Myocardial Perfusion in Patients With a Totally Occluded Left Anterior Descending Coronary Artery Reinjected by a Normal Right Coronary Artery: The Role of Collateral Circulation

In this article, myocardial perfusion in patients with a totally occluded left anterior descending artery reinjected by a normal right coronary artery is assessed using stress single photon emission computed tomography (SPECT). In all, 20 patients, with a totally occluded left anterior descending artery reinjected by normal right coronary artery, underwent myocardial single photon emission computed tomography imaging within 60 days of angiography. All patients had abnormal perfusion single photon emission computed tomography results and 70% had reversible defects. Perfusion defects at rest were present in 75% of patients, with perinecrotic residual ischemia in 45% of patients whereas for 30% of patients, no viable myocardium was detected in the collateral-dependent segments. In all, 25% of patients had no resting perfusion defects but all are presented with stress-induced ischemia. Collaterals are not protective against stress-induced ischemia, but they can preserve myocardial viability. This conclusion is highly supported by the presence of residual ischemia in the collateral-dependent segments.

Increased circulating monocyte count is related to good collateral development in coronary artery disease

Monocytes have been shown to take an important role in collateral growth in animal studies. The aim of the study was to investigate the relation of circulating monocyte count with collateral development in patients with severely stenotic CAD. Patients who had > or =95% stenosis in at least one major coronary artery were included in the study. Coronary angiograms of 210 eligible patients from our database were analyzed again and 103 of them had good and 107 had poor collateral development according to Cohen-Rentrop method. Only the monocyte count was found to be significantly different between two groups (671+/-218 mm(-3) versus 522+/-195 mm(-3), p<0.001) when multivariate analysis was performed and an increased monocyte count was observed in the good collateral group (Odds ration [OR], 2.918; 95% confidence interval [CI], 1.281-6.648, p=0.011). This study in which the relationship between monocyte count in blood and collateral development was disclosed has a potential importance in clinical and basic cardiovascular medicine.

Proteomic analysis of left ventricular tissues following intermittent myocardial ischemia during coronary collateralization in rabbits

BACKGROUND

Repeated transient myocardial ischemia may offer favorable effects to coronary perfusion via collateral circulation, although the underlying molecular mechanisms still remain unclear. This study was designed to evaluate the proteomic changes during this process.

METHODS

Rabbits were randomly divided into sham-operated and ischemic groups (5 each) and were subjected to intermittent myocardial ischemia by inflation or deflation of pneumatic occluders for 4 weeks to establish a controlled myocardial ischemic model. Isolated hearts were subjected to histological observation, microspheric detection, capillary counting and proteomic analysis.

RESULTS

Elevation of ST segment or back to normal in Lead-II electrocardiogram could be induced by occluders without overt histological and cardiac troponin I alterations. Regional coronary collateral blood flow exhibited a remarkable increase following intermittent inflation of occluders in the ischemic group (P<0.01). Simultaneously, capillary numbers per unit area were significantly different between groups (P<0.01). Twenty-three differentially expressed protein spots were separated by two-dimensional gel electrophoresis and 13 out of them were identified by MALDI-TOF-MS.

CONCLUSION

The present study indicates that the differentially expressed proteins involved in proliferation, growth and energy metabolism following intermittent myocardial ischemia without ischemia-reperfusion injury are likely associated with the development of collateralization beneficial to coronary circulation.

Transcriptional profiling in coronary artery disease: indications for novel markers of coronary collateralization

BACKGROUND

The development of collateral circulation plays an important role in protecting tissues from ischemic damage, and its stimulation has emerged as one of principal approaches to therapeutic angiogenesis. Clinical observations have documented substantial differences in the extent of collateralization among patients with coronary artery disease (CAD), with some individuals demonstrating marked abundance and others showing nearly complete absence of these vessels. Recent studies have suggested that circulating monocytes play a major role in collateral growth. The present study was undertaken to determine transcriptional profiles of circulating monocytes in CAD patients with different extents of collateral growth.

METHODS AND RESULTS

Monocyte transcriptomes from CAD patients with and without collateral vessels were obtained by use of high-throughput expression profiling. Using a newly developed redundancy-based data mining method, we have identified a set of molecular markers characteristic of a "noncollateralgenic" phenotype. Moreover, we show that these transcriptional abnormalities are independent of the severity of CAD or any other known clinical parameter thought to affect collateral development and correlated with protein expression levels in monocytes and plasma.

CONCLUSIONS

Monocyte transcription profiling identifies sets of patients with extensive versus poorly developed collateral circulation. Thus, genetic factors may heavily influence coronary collateral vessel growth in CAD and affect prognosis and response to therapeutic interventions.

Intra-coronary high-dose CD34+ stem cells in patients with chronic ischemic heart disease: A 12-month follow-up

Current stem cell protocols for ischemic heart disease are limited by the small numbers of cells that can be obtained by bone marrow aspirate. To increase myocardial delivery of bone marrow stem cells in patients with chronic ischemic heart disease (CIHD), we used granulocyte colony stimulating factor (G-CSF) for bone marrow mobilization of CD34+ cells, enabling intracoronary infusion of large numbers of CD34+ stem cells. Patients with CIHD (n = 5) demonstrated significantly reduced numbers of CD34+ cells mobilized by G-CSF in comparison to age-matched controls. Sustained reduction in anginal symptoms and improvement in quality of life scores was seen in all patients following infusion of cells. Moreover, mean collateral flow grade at 12-month follow-up angiography significantly improved, indicating sustained myocardial neovascularization. No proliferative retinopathy was induced and no in-stent restenosis seen. However, in two patients with documented increase in collateral flow, complications arose, one developing an acute coronary syndrome and the other a lentigo maligna. These results demonstrate the feasibility of G-CSF mobilization, leukapheresis and intracoronary transfer of CD34+ stem cells in patients with CIHD, but longer-term studies are required to ensure that this protocol is safe and effective.

Catecholamines augment collateral vessel growth and angiogenesis in hindlimb ischemia

Catecholamine stimulation of α1-adrenoceptors exerts growth factor-like activity, mediated by generation of reactive oxygen species, on arterial smooth muscle cells and adventitial fibroblasts and contributes to hypertrophy and hyperplasia in models of vascular injury and disease. Adrenergic trophic activity also contributes to flow-mediated positive arterial remodeling by augmenting proliferation and leukocyte accumulation. To further examine this concept, we studied whether catecholamines contribute to collateral growth and angiogenesis in hindlimb insufficiency. Support for this hypothesis includes the above-mentioned studies, evidence that ischemia augments norepinephrine release from sympathetic nerves, and proposed involvement of reactive oxygen species in angiogenesis and collateral growth. Mice deficient in catecholamine synthesis [by gene deletion of dopamine β-hydroxylase (DBH−/−)] were studied. At 3 wk after femoral artery ligation, increases in adductor muscle perfusion were similar in DBH−/− and wild-type mice, whereas recovery of plantar perfusion and calf microsphere flow were attenuated, although not significantly. Preexisting collaterals in adductor of wild-type mice showed increases in lumen diameter (60%) and medial and adventitial thickness (57 and 119%, P < 0.05 here and below). Lumen diameter increased similarly in DBH−/− mice (52%); however, increases in medial and adventitial thicknesses were reduced (30 and 65%). Leukocyte accumulation in the adventitia/periadventitia of collaterals was 39% less in DBH−/− mice. Increased density of α-smooth muscle actin-positive vessels in wild-type adductor (45%) was inhibited in DBH−/− mice (2%). Although both groups experienced similar atrophy in the gastrocnemius (∼22%), the increase in capillary-to-muscle fiber ratio in wild-type mice (21%) was inhibited in DBH−/− mice (7%). These data suggest that catecholamines may contribute to collateral growth and angiogenesis in tissue ischemia.

Relation of platelet activation to coronary angiographic severity and collateralization

We investigated whether platelet activation can be correlated with angiographic severity and the degree of collateralization in coronary artery disease (CAD), as well as endothelial damage/dysfunction. No studies have attempted to correlate platelet activation status, as measured by soluble plasma markers (soluble CD40 ligand, soluble P-selectin, soluble glycoprotein V), with the appearance of diseased coronary arteries. We found evidence of increased platelet activation in CAD, but a lack of correlation between the degree of platelet activation and the angiographic disease severity, which may reflect the presence of disease elsewhere or the presence of coronary atheroma not detected by angiography.