Importance of collateral circulation for prevention of left ventricular aneurysm formation in acute myocardial infarction

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.

The Usefulness of Admission Plasma NT-pro BNP Level to Predict Left Ventricular Aneurysm Formation after Acute ST-Segment Elevation Myocardial Infarction

Background

Left ventricular aneurysm (LVA) is an important complication of acute myocardial infarction. In this study, we investigated the role of N- Terminal pro B type natriuretic peptide level to predict the LVA development after acute ST-segment elevation myocardial infarction (STEMI).

Methods

We prospectively enrolled 1519 consecutive patients with STEMI. Patients were divided into two groups according to LVA development within the six months after index myocardial infarction. Patients with or without LVAs were examined to determine if a significant relationship existed between the baseline N- Terminal pro B type natriuretic peptide values and clinical characteristics. A p-value < 0.05 was considered statistically significant.

Results

LVA was detected in 157 patients (10.3%). The baseline N- Terminal pro- B type natriuretic peptide level was significantly higher in patients who developed LVA after acute MI (523.5 ± 231.1 pg/mL vs. 192.3 ± 176.6 pg/mL, respectively, p < 0.001). Independent predictors of LVA formation after acute myocardial infarction was age > 65 y, smoking, Killip class > 2, previous coronary artery bypass graft, post-myocardial infarction heart failure, left ventricular ejection fraction < 50%, failure of reperfusion, no-reflow phenomenon, peak troponin I and CK-MB and NT-pro BNP > 400 pg/mL at admission.

Conclusions

Our findings indicate that plasma N- Terminal pro B type natriuretic peptide level at admission among other variables provides valuable predictive information regarding the development of LVA after acute STEMI.

Early recruitment of coronary collateral circulation: impact in late presentation nonreperfused acute coronary occlusion

BACKGROUND

Debate still remains on whether the presence of early recruited collateral circulation (ERCC) in the setting of an acute coronary occlusion (ACO) has a prognosis benefit. Some previous reports have shown lower mortality and morbidity rates in well-collateralized patients compared with those with poorly recruited collateral circulation (PCC), but others have not. In the primary angioplasty era, the role of collateral circulation in these studies may have been influenced by the effect of early reperfusion. The actual impact of ERCC in ACO can be clarified by studying its effect on nonreperfused patients.

OBJECTIVE

This study aimed to compare the 1-year clinical outcome in nonreperfused late presentation ACO in a major coronary artery with ERCC versus PCC.

PATIENTS AND METHODS

Between 2008 and 2015, we included 164 patients with a nonreperfused late presentation ACO. The patients were divided according to the presence of angiographic ERCC (Rentrop 2-3) or PCC (Rentrop 0-1). ERCC was present in 54% of patients. Patients with ERCC less often presented with cardiogenic shock (P=0.02) and the right coronary artery was the most frequent culprit vessel (P=0.02). The presence of PCC was associated independently with higher 1-year cardiovascular mortality [hazard ratio (HR): 6.92; 95% confidence interval (95%CI): 1.37-34.7; P=0.019], 1-year total mortality (HR: 5.79; 95%CI: 1.95-17.1; P=0.001), and 1-year major adverse cardiac event (HR: 8.05; 95%CI: 1.73-37.4; P<0.01).

CONCLUSION

The presence of angiographically PCC in the setting of late presentation nonreperfused ACO is relatively infrequent (46%) and is associated with worse 1-year major clinical outcomes.

Platelet to Lymphocyte Ratio in Cardiovascular Diseases: A Systematic Review

The platelet to lymphocyte ratio (PLR) is an integrated reflection of 2 opposite thrombotic/inflammatory pathways that are easily calculated from a complete blood count. The PLR initially served as a systemic inflammatory biomarker to predict the prognosis of neoplastic diseases. In recent years, the PLR has been used as a prognostic marker in cardiovascular (CV) conditions. In this review, we consider the evidence regarding the association of the PLR with CV disease (CVD) and its possible use as a prognostic marker of CVD. The role of PLR has been investigated in CV conditions in several studies. We assessed clinical trials using PubMed, EMBASE, and Web of Science (up to April 18, 2018) to evaluate the association between PLR and mortality/major adverse cardiac events in these conditions. Most of these studies reported significant relationships between a high PLR and diverse outcomes. In conclusion, we suggest that PLR is a cheap and easily available systemic inflammatory marker that can predict distinct outcomes in different types of CVD.

Disparate Impact of Ischemic Injury on Regional Wall Dysfunction in Acute Anterior vs Inferior Myocardial Infarction

BACKGROUND

Acute transmural ischemia should induce similar magnitude of wall motion abnormality (WMA) in both anterior myocardial infarction (AMI) and inferior (IMI). However, patients with AMI generally suffer more severe hemodynamic compromise.

METHODS

This retrospective study compared WMA's in ST segment elevation MI patients undergoing primary reperfusion and subsequent cardiac MRI. Regional systolic wall motion and thickening were assessed in all segments throughout the left ventricle (LV).

RESULTS

We analyzed 37 patients (AMI = 24 vs IMI = 13). Reperfusion success was achieved in all and there were no differences between groups in door-to-balloon time (AMI median 77 vs IMI 119 min, p = 0.085). Compared to IMI, in AMI LV ejection fraction was more depressed (37 ± 7.6% vs 51 ± 10.3%, P = 0.0006) and regional WMA more severe (total regional WMA score = 2.63 ± 0.53 vs IMI = 2.1 ± 0.52, P = 0.007). Regional dyskinesis was commonly observed in AMI patients but was rare in IMI (79% vs 7% of cases). Similarly, AMI manifested systolic thinning, whereas thickening was depressed but still present in IMI patients. Strikingly, WMA severity differed downstream relative to the origin of the infarct artery: In all AMI cases, WMA worsened from proximal anterior toward the distal apical zone; in IMI the pattern was reverse, with WMA consistently most severe in the basal segment of the inferior-posterior wall with preservation toward the apical distribution of the infarct vessel.

CONCLUSION

These results demonstrate a disparate impact of ischemic injury on mechanical performance of the anterior vs inferior-posterior walls. These findings may be attributable to differences between the walls in architecture, mechanics and coronary blood flow. These observations may have implications for myocardial salvage, remodeling and prognosis.

Macrophage migration inhibitory factor (MIF) is associated with degree of collateralization in patients with totally occluded coronary arteries

BACKGROUND

Collaterals in patients with coronary artery disease (CAD) limit myocardial infarction and improve survival. Macrophage migration inhibitory factor (MIF) might play a role in collateral development. We aimed this study to evaluate the association of Macrophage migration Inhibitory Factor (MIF) with the extent of collateralization in patients with coronary occlusion.

METHODS AND RESULTS

We consecutively enrolled: a) 40 patients undergoing PCI of a chronic coronary total occlusion (CTO); b) 26 patients with ST-elevation myocardial infarction (STEMI) undergoing primary PCI (pPCI) of the infarct-related artery (IRA); c) 12 control patients undergoing angiography without significant coronary artery disease (CTRL). CTO patients were grouped in high (HCG) or low collateralization group (LCG). STEMI patients were grouped in COLL+ or COLL- group depending on the presence of collaterals to the IRA. Blood sampling was performed from the arterial sheath (SYSTEMIC), and distal to the occlusion (LOCAL). SYSTEMIC and LOCAL levels were significantly different between the 3 groups. A progressive increase in MIF ratio (defined as: % (LOCAL-SYSTEMIC)/SYSTEMIC) was observed (CTRL: -0.5[-23;28] vs. CTO: 4[-19;32] vs. STEMI: 55[37;87], p < 0.01). In CTO, MIF ratio was significantly higher in HCG vs. LCG (68 [45;120] vs. 46 [29;66], p = 0.02). In STEMI, MIF ratio was not different between COLL+ and COLL- patients; however, in COLL+, LOCAL was significantly higher as compared with SYSTEMIC (83 ng/ml [63;100] vs. 67 ng/ml [40;79], p = 0.04).

CONCLUSIONS

Local MIF is significantly associated with the extent of collateralization in both acute and chronic total coronary occlusions.

Effect of Coronary Collaterals on Prognosis in Patients Undergoing Primary Percutaneous Coronary Intervention for Acute ST-Segment Elevation Myocardial Infarction: A Meta-Analysis

The impact of coronary collaterals on the prognosis in patients with acute ST-segment elevation myocardial infarction (STEMI) in the era of coronary revascularization remains controversial. The purpose of this meta-analysis was to investigate the effect of coronary collateral on clinical outcomes, especially mortality (≥6 months), in patients undergoing primary percutaneous coronary intervention (PCI) for STEMI. Eligible observational studies were selected by searching PubMed, EMBASE, and Cochrane Library up to August 9, 2017. Overall, 14 observational studies involving 10 411 patients were included. Coronary collaterals were found to reduce the risk of long-term mortality (≥6 months; risk ratio [RR]: 0.65, 95% confidence interval [CI]: 0.55-0.76) as well as in-hospital plus 30-day mortality (RR: 0.61, 95% CI: 0.47-0.78) in patients undergoing PCI for STEMI. In addition, pooling the risk-adjusted or propensity-matched data showed a significant reduction in long-term mortality (RR: 0.68, 95% CI: 0.49-0.95) and in-hospital plus 30-day mortality (RR: 0.27, 95% CI: 0.13-0.55) in patients with collateral circulation. However, no significant difference was found in the risk of recurrent myocardial infarction and target vessel revascularization between the 2 groups. Therefore, it was found that coronary collaterals have a beneficial effect on long-term survival (≥6 months) as well as in-hospital plus 30-day survival in patients undergoing primary PCI for STEMI.

The role of coronary artery collaterals in the preservation of left ventricular function: a study to address a long-standing controversy

Introduction:

The functional significance of coronary artery collateral (CAC) vasculature in humans has been debated for decades and this has been compounded by the lack of a standard, systematic, objective method of grading and documenting CAC flow in man. CACs serve as alternative conduits for blood in obstructive coronary artery disease. This study aimed to evaluate the impact of CACs on left ventricular function in the presence of total coronary arterial occlusion.

Methods:

The study group included the coronary angiographic records of 97 patients (mean age: 59 ± 8 years). CACs were graded from 0–3 based on the collateral connection between the donor and recipient arteries. Left ventricular function was computed from the ventriculogram and expressed as ejection fraction (EF).

Results:

The mean EF of the patients with grades 0, 1, 2 and 3 CACs were calculated as 50.4, 47, 60.5 and 70%, respectively. A significant difference was recorded in the mean EF calculated for the different CAC grades (p = 0.001). There was a significant positive correlation (p < 0.001; r = 0.478) between the mean EF and the CAC grades.

Conclusion:

The patients with better coronary collateral grades had a higher mean EF. Therefore, as the grade of CACs increased, there was an improvement in their ability to preserve left ventricular function.

PreSERVE-AMI: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial of Intracoronary Administration of Autologous CD34+ Cells in Patients With Left Ventricular Dysfunction Post STEMI

RATIONALE

Despite direct immediate intervention and therapy, ST-segment-elevation myocardial infarction (STEMI) victims remain at risk for infarct expansion, heart failure, reinfarction, repeat revascularization, and death.

OBJECTIVE

To evaluate the safety and bioactivity of autologous CD34+ cell (CLBS10) intracoronary infusion in patients with left ventricular dysfunction post STEMI.

METHODS AND RESULTS

Patients who underwent successful stenting for STEMI and had left ventricular dysfunction (ejection fraction≤48%) ≥4 days poststent were eligible for enrollment. Subjects (N=161) underwent mini bone marrow harvest and were randomized 1:1 to receive (1) autologous CD34+ cells (minimum 10 mol/L±20% cells; N=78) or (2) diluent alone (N=83), via intracoronary infusion. The primary safety end point was adverse events, serious adverse events, and major adverse cardiac event. The primary efficacy end point was change in resting myocardial perfusion over 6 months. No differences in myocardial perfusion or adverse events were observed between the control and treatment groups, although increased perfusion was observed within each group from baseline to 6 months (P<0.001). In secondary analyses, when adjusted for time of ischemia, a consistently favorable cell dose-dependent effect was observed in the change in left ventricular ejection fraction and infarct size, and the duration of time subjects was alive and out of hospital (P=0.05). At 1 year, 3.6% (N=3) and 0% deaths were observed in the control and treatment group, respectively.

CONCLUSIONS

This PreSERVE-AMI (Phase 2, randomized, double-blind, placebo-controlled trial) represents the largest study of cell-based therapy for STEMI completed in the United States and provides evidence supporting safety and potential efficacy in patients with left ventricular dysfunction post STEMI who are at risk for death and major morbidity.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01495364.

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.

The relation of platelet-lymphocyte ratio and coronary collateral circulation in patients with non-ST segment elevation myocardial infarction

Introduction

Recently, platelet-to-lymphocyte ratio (PLR) has emerged as a significant inflammatory marker and a novel predictor of major adverse consequences in cardiovascular disease.

Aim

In this study, we aimed to explore the relationship between PLR and coronary collateral circulation (CCC) in patients with non-ST elevation myocardial infarction (NSTEMI).

Material and methods

Clinical and laboratory data of 386 patients who underwent coronary angiography were evaluated retrospectively. The patients were classified into 2 groups as follows: poor CCC (group 1: Rentrop grades 0–1) and good CCC (group 2: Rentrop grades 2–3). The PLR was calculated from the complete blood count.

Results

The PLR values of the patients with poor CCC were significantly higher than those of patients with good CCC (153.9 ±26.6 vs. 129.8 ±23.5, p < 0.001). In the multiple logistic regression tests, PLR (odds ratio: 1.51, 95% confidence interval: 1.27–1.74; p < 0.001) and hs-CRP (odds ratio: 1.56, 95% CI: 1.03–2.11; p < 0.001) were found to be independent predictors of poor CCC. The receiver operating characteristic (ROC) curve analysis yielded a cutoff value of 140.5 for PLR to predict poor CCC with 79% sensitivity and 71% specificity, with the area under the ROC curve being 0.792 (95% CI: 0.721–0.864).

Conclusions

Our study revealed that high PLR is independently associated with poor coronary collateral circulation in patients with NSTEMI.

Impact of coronary collaterals on in-hospital and 5-year mortality after ST-elevation myocardial infarction in the contemporary percutaneous coronary intervention era: a prospective observational study

OBJECTIVES

To evaluate the short-term and long-term prognostic impacts of acute phase coronary collaterals to occluded infarct-related arteries (IRA) after ST-elevation myocardial infarction (STEMI) in the percutaneous coronary intervention (PCI) era.

DESIGN

A prospective observational study.

SETTING

Osaka Acute Coronary Insufficiency Study (OACIS) in Japan.

PARTICIPANTS

3340 patients with STEMI from the OACIS database who were admitted to hospitals within 24 hours from the onset and who had a completely occluded IRA.

INTERVENTIONS

Patients were divided into 4 groups according to the Rentrop collateral score (RCS) by angiography on admission (RCS-0, no visible collaterals; RCS-1, collaterals without IRA filling; RCS-2, collaterals with partial IRA filling; and RCS-3, collaterals with complete IRA filling).

PRIMARY OUTCOME MEASURES

In-hospital and 5-year mortality.

RESULTS

Patients with RCS-0/3 were older than patients with RCS-1/2, and the prevalence of previous myocardial infarction was highest in patients with RCS-3. Median peak creatinine phosphokinase levels decreased as RCS increases (p<0.001), suggesting the acute cardioprotective effects of collaterals. Although RCS-1 and RCS-2 collaterals were associated with better in-hospital mortality (adjusted OR 0.48, p=0.046 and 0.38, p=0.010 for RCS-1 and RCS-2, respectively) and 5-year mortality (adjusted HR 0.53, p=0.004 and 0.46, p<0.001 for RCS-1 and RCS-2, respectively) as compared with R-0, presence of RCS-3 collaterals was not associated with improved in-hospital (adjusted OR 1.35, p=0.331) and 5-year mortality (adjusted HR 0.98, p=0.920), possibly because worse clinical profiles in patients with RCS-3 may mask mortality benefit of coronary collaterals.

CONCLUSIONS

Presence of acute phase coronary collaterals such as RCS-1 and RCS-2 were associated with better in-hospital and 5-year mortality after STEMI in the contemporary PCI era.

Vascular endothelial growth factor and hypoxia-inducible factor-1α gene polymorphisms and coronary collateral formation in patients with coronary chronic total occlusions

Introduction:

We evaluated the association between two single nucleotide polymorphisms of the vascular endothelial growth factor gene and one of the hypoxia-inducible factor-1α gene and the degree of coronary collateral formation in patients with a coronary chronic total occlusion.

Methods:

Totally, 98 patients with symptomatic coronary artery disease and a chronic total occlusion observed during coronary angiography were recruited. Genotyping of two vascular endothelial growth factor promoter single nucleotide polymorphisms (−152G>A and −165C>T) and the C1772T single nucleotide polymorphism of hypoxia-inducible factor-1α were performed using polymerase chain reaction and restriction fragment length polymorphism analysis. The presence and extent of collateral vessel filling was scored by blinded observers using the Rentrop grade.

Results:

We found no association between the vascular endothelial growth factor −152G>A, −165C>T and hypoxia-inducible factor-1α −1772C>T with the presence and filling of coronary collateral vessels. A history of percutaneous coronary intervention and transient ischaemic attack/cerebrovascular accident were associated with the presence of enhanced collateral vessel formation following binary logistic regression analysis.

Conclusion:

The study findings suggest that coronary collateral formation is not associated with the tested polymorphic variants of vascular endothelial growth factor and hypoxia-inducible factor-1α in patients with symptomatic coronary artery disease and the presence of a chronic total occlusion.

Emerging importance of chemokine receptor CXCR3 and its ligands in cardiovascular diseases

The CXC chemokines, CXCL4, -9, -10, -11, CXCL4L1, and the CC chemokine CCL21, activate CXC chemokine receptor 3 (CXCR3), a cell-surface G protein-coupled receptor expressed mainly by Th1 cells, cytotoxic T (Tc) cells and NK cells that have a key role in immunity and inflammation. However, CXCR3 is also expressed by vascular smooth muscle and endothelial cells, and appears to be important in controlling physiological vascular function. In the last decade, evidence from pre-clinical and clinical studies has revealed the participation of CXCR3 and its ligands in multiple cardiovascular diseases (CVDs) of different aetiologies including atherosclerosis, hypertension, cardiac hypertrophy and heart failure, as well as in heart transplant rejection and transplant coronary artery disease (CAD). CXCR3 ligands have also proven to be valid biomarkers for the development of heart failure and left ventricular dysfunction, suggesting an underlining pathophysiological relation between levels of these chemokines and the development of adverse cardiac remodelling. The observation that several of the above-mentioned chemokines exert biological actions independent of CXCR3 provides both opportunities and challenges for developing effective drug strategies. In this review, we provide evidence to support our contention that CXCR3 and its ligands actively participate in the development and progression of CVDs, and may additionally have utility as diagnostic and prognostic biomarkers.

Impact of Coronary Collateral Circulation on In-Hospital Death in Patients with Inferior ST Elevation Myocardial Infarction

Objectives. Coronary collateral circulation (CCC) may limit the size of right ventricular (RV) infarcts but does not fully explain the relationship between CCC and clinical adverse events in patients with inferior STEMI. In this study, it was aimed to assess the relationship between preintervention angiographic evidence of CCC and clinical outcomes in patients with inferior STEMI who have undergone percutaneous coronary intervention. Methods. A total of 235 inferior STEMI patients who presented within the first 12 hours from the symptom onset were included. CCC to the right coronary artery (RCA) before angioplasty were angiographically assessed, establishing two groups: 147 (63%) patients without CCC and 88 (37%) with CCC according to presence of CCC. Results. RV infarction, complete atrioventricular block, VT/VF, cardiogenic shock, and in-hospital death were noted less frequently in patients with CCC than in those without CCC. Absence of CCC to RCA was found to be the independent predictor for in-hospital death among them (odds ratio 4.0, 95% CI 1.8-12.6; p = 0.03). Conclusion. Presence of angiographically detectable CCC was associated with better in-hospital outcomes including RV infarction, complete AV block, cardiogenic shock, and VT/VF in patients with inferior STEMI.

Collateral Circulation in Chronic Total Occlusions – an interventional perspective

Human coronary collaterals are inter-coronary communications that are believed to be present from birth. In the presence of chronic total occlusions, recruitment of flow via these collateral anastomoses to the arterial segment distal to occlusion provide an alternative source of blood flow to the myocardial segment at risk. This mitigates the ischemic injury. Clinical outcome of coronary occlusion ie. severity of myocardial infarction/ischemia, impairment of cardiac function and possibly survival depends not only on the acuity of the occlusion, extent of jeopardized myocardium, duration of ischemia but also to the adequacy of collateral circulation. Adequacy of collateral circulation can be assessed by various methods. These coronary collateral channels have been used successfully as a retrograde access route for percutaneous recanalization of chronic total occlusions. Factors that promote angiogenesis and further collateral remodeling ie. arteriogenesis have been identified. Promotion of collateral growth as a therapeutic target in patients with no suitable revascularization option is an exciting proposal.

Epicardial adipose tissue is related to coronary collateral vessel formation in patients with acute coronary syndrome

OBJECTIVES

Epicardial adipose tissue (EAT) is the ectopic fat surrounding the heart, and it may contribute to coronary collateral vessel (CCV) formation. We aimed to evaluate the association of EAT with the presence of CCV in patients with acute coronary syndrome (ACS).

DESIGN

A total of 230 patients with ACS were included. The CCVs were graded according to the Rentrop scoring system, and a Rentrop grade 0-1 was accepted as low-grade CCV group, Rentrop grade 2-3 was accepted as high-grade CCV group.

RESULTS

According to angiography, 70 (30%) patients constituted the high-grade CCV group and 160 (70%) constituted the low-grade CCV group. The high-grade CCV group had thicker EAT than the low-grade CCV group (6.1 ± 1.4 vs. 5.3 ± 1.4 mm; p = 0.001). Multivariate logistic regression analysis showed that presence of CCV was independently associated with EAT thickness, ejection fraction, presenting with ST-segment elevation myocardial infarction, and presence of angina on admission. EAT thickness of > 5.7 mm can independently predict high-grade CCV with 73% sensitivity and 69% specificity (area under the curve or AUC: 0.65; 95% confidence interval or CI: 0.57-0.72).

CONCLUSIONS

EAT thickness on admission was associated with the presence of CCVs in patients with ACS.

Sensitivity analysis and parameter estimation of a coronary circulation model for triple-vessel disease

Mathematical models of the coronary circulation have been shown to provide useful information for the analysis of intracoronary blood flow and pressure measurements acquired during coronary artery bypass graft (CABG) surgery. Although some efforts towards the patient-specific estimation of model parameters have been presented in this context, they are based on simplifying hypotheses about the collateral circulation and do not take advantage of the whole set of data acquired during CABG. In order to overcome these limitations, this paper presents an exhaustive parameter sensitivity analysis and a multiobjective patient-specific parameter estimation method, applied to a model of the coronary circulation of patients with triple vessel disease. The results of the sensitivity analysis highlighted the importance of capillary and collateral development. On the other hand, the estimation method was applied to intraoperative clinical data from ten patients obtained during CABG, which permitted to assess patient-specific collateral vessel situations. These approaches provide new insights regarding the heterogeneous configuration of the collateral circulation.

Left ventricular aneurysm repair with use of a bovine pericardial patch

Left ventricular aneurysm, which can impair systolic function, has a reported incidence of 10% to 35% in patients after myocardial infarction. In a 58-year-old woman who had a history of myocardial infarction, we excised a large left ventricular aneurysm and restored left ventricular geometry with use of a bovine pericardial patch. The aneurysm's characteristics and the patient's preoperative left ventricular ejection fraction of 0.25 had indicated surgical intervention. The patient had an uneventful postoperative course, and her left ventricular ejection fraction was 0.50 to 0.55 on the 4th postoperative day. This case illustrates the value of surgical treatment for patients who have a debilitating left ventricular aneurysm.

Effects of the coronary collateral circulation on the Tp-e interval and Tp-e/QT ratio in patients with stable coronary artery disease

BACKGROUND

The clinical utility of the Tp-e interval and Tp-e/QT ratio in the risk stratification of ventricular arrhythmic events is controversial. Therefore, we investigated the impact of CCC on these electrocardiographic indexes in the course of stable CAD.

METHODS

Two hundred three consecutive patients with stable CAD who underwent coronary angiography and had documented total occlusion of one of the major coronary arteries were enrolled in this prospective cross-sectional study. The Tp-e interval and Tp-e/QT ratio were measured by 12-lead electrocardiogram.

RESULTS

The Tp-e interval, cTp-e interval, Tp-e/QT ratio, and cTp-e/QT ratio were lower in the grade 3 CCC group compared with the others in all leads. Multivariate linear regression analyses was performed to identify the clinical factors affecting the cTp-e interval and was indicated that age (β = 0.261, P < 0.001), male sex (β = 0.334, P < 0.001), poor Rentrop grade (β = -0.228, P < 0.001), and NLR (β = 0.137, P = 0.027) were independent predictors of a prolonged cTp-e interval.

CONCLUSION

It could be concluded that the decreased dispersion of ventricular repolarization might contribute to the lower incidence of ventricular arrhythmias and SCD in CAD patients with a good CCC.

Coronary collateral circulation: Effects on outcomes of acute anterior myocardial infarction after primary percutaneous coronary intervention

Background

To investigate the effects of collateral coronary circulation on the outcome of the patients with anterior myocardial infarction (MI) with left anterior desending artery occlusion abruptly.

Methods

Data of 189 patients with acute anterior MI who had a primary percutaneous coronary intervention (PCI) in the first 12 h from the onset of symptoms between January 2004 and December 2008 were retrospective analyzed. Left anterior descending arteries (LAD) of all patients were occluded. LADs were reopened with primary PCI. According to the collateral circulation, all patients were classified to two groups: no collateral group (n = 111), patients without angiographic collateral filling of LAD or side branches (collateral index 0) and collateral group (n = 78), and patients with angiographic collateral filling of LAD or side branches (collateral index 1, 2 or 3). At one year's follow-up, the occurrence of death, reinfarction, stent thrombosis (ST), target vessel revascularization and readmission because of heart failure were observed.

Results

At one year, the mortality was lower in patients with collateral circulation compared with those without collateral circulation (1% vs. 8%, P = 0.049), whereas there were no differences in the occurrence of reinfarction, ST, target vessel revascularization and readmission because of heart failure. The occurrence of composite of endpoint was lower in patients with collateral circulation compared with those without collateral circulation (12% vs. 26%; P = 0.014).

Conclusions

Pre-exist collateral circulation may prefigure the satisfactory prognosis to the patients with acute anterior MI after primary PCI in the first 12 h of MI onset.

Wound healing gene therapy: cartilage regeneration induced by vascular endothelial growth factor plasmid

AIMS

The identification of growth factors and cytokines with angiogenic activity has enabled new therapeutic treatments for a variety of diseases; this concept is called therapeutic angiogenesis. The vascular endothelial growth factor (VEGF) is the most critical regulator of vascular formation. In the present study, we were interested in the therapeutic angiogenesis effect using plasmid transfer of human complementary DNA VEGF(165) (phVEGF(165)) in experimental skin and cartilage trauma.

METHODS

Ten BALB/c mice were used for cartilage injury model. At 6 weeks of age, all mice were ear-punched, resulting in 2-mm-diameter puncture through the center of both pinnae. Each mouse got phVEGF(165) injection into the first ear and vector without insert or saline injection into the second one. The healing process was followed. The hollow diameter was measured on days 0, 14, and 42. Histological sections of experimental and control pinnae were taken from days 1, 3, 5, 7, 9, 11, 13, 15, 20, and 30 after experimental injury for hematoxylin and eosin and periodic acid Schiff staining and for human VEGF immunocytochemistry. The expression of human VEGF was also checked by real-time polymerase chain reaction in formalin-fixed, paraffin-embedded tissue sections.

KEY FINDINGS

In BALB/c mouse strain, a significant angiogenesis promotion and cartilage repair were observed after phVEGF(165) injection into the punched ear area.

SIGNIFICANCE

We suggest that administering phVEGF(165) leads to faster cartilage regeneration even if not only on the angiogenic basis.

Mildly decreased glomerular filtration rate is associated with poor coronary collateral circulation in patients with coronary artery disease

BACKGROUND

The aim of this study was to evaluate the association between mildly decreased glomerular filtration rate (GFR) and coronary collateral circulation (CCC).

HYPOTHESIS

There would be an association between mildly decreased GFR and CCC.

METHODS

Patients who had an occlusion in at least 1 major coronary artery were included in this study. Patients with severely and moderately decreased GFR were excluded. Patient data were obtained from their files. To classify CCC, we used the Rentrop classification. Patients were classified as having poor CCC (Rentrop grades 0 to 1) or good CCC (Rentrop grades 2 to 3). We used the Modification of Diet in Renal Disease (MDRD) equation to calculate GFR. Mildly decreased GFR was defined as 60 mL/min per 1.73 m(2) ≥ eGFR ≤89 mL/min per 1.73 m(2) according to the MDRD definition. Multivariate logistic regression analysis was performed to determine independent variables.

RESULTS

The study group consisted of 299 patients. Ninety-three patients had poor CCC and 206 patients had good CCC. The frequency of mildly decreased GFR was higher in the poor CCC group than in the good CCC group (P<0.001). Also, the frequency of diabetes and dyslipidemia, and the plasma high sensitive C-reactive protein levels, were higher in the poor CCC group (P = 0.003, P = 0.018, P<0.001, respectively). Logistic regression analysis revealed that eGFR is an independent predictor of CCC (B = 1.68; odds ratio = 5.4; P<0.001; 95% confidence interval, 3.1-9.4).

CONCLUSIONS

We found that CCC was worse in patients with mildly decreased GFR compared to patients with normal GFR in patients with coronary artery disease.

Plasma chemokine levels are associated with the presence and extent of angiographic coronary collaterals in chronic ischemic heart disease

BACKGROUND

In patients with chronic ischemic heart disease (IHD), the presence and extent of spontaneously visible coronary collaterals are powerful determinants of clinical outcome. There is marked heterogeneity in the recruitment of coronary collaterals amongst patients with similar degrees of coronary artery stenoses, but the biological basis of this heterogeneity is not known. Chemokines are potent mediators of vascular remodeling in diverse biological settings. Their role in coronary collateralization has not been investigated. We sought to determine whether plasma levels of angiogenic and angiostatic chemokines are associated with of the presence and extent of coronary collaterals in patients with chronic IHD.

METHODOLOGY/PRINCIPAL FINDINGS

We measured plasma concentrations of angiogenic and angiostatic chemokine ligands in 156 consecutive subjects undergoing coronary angiography with at least one ≥90% coronary stenosis and determined the presence and extent of spontaneously visible coronary collaterals using the Rentrop scoring system. Eighty-eight subjects (56%) had evidence of coronary collaterals. In a multivariable regression model, the concentration of the angiogenic ligands CXCL5, CXCL8 and CXCL12, hyperlipidemia, and an occluded artery were associated with the presence of collaterals; conversely, the concentration of the angiostatic ligand CXCL11, interferon-γ, hypertension and diabetes were associated with the absence of collaterals (ROC area 0.91). When analyzed according to extent of collateralization, higher Rentrop scores were significantly associated with increased concentration of the angiogenic ligand CXCL1 (p<0.0001), and decreased concentrations of angiostatic ligands CXCL9 (p<0.0001), CXCL10 (p = 0.002), and CXCL11 (p = 0.0002), and interferon-γ (p = 0.0004).

CONCLUSIONS/SIGNIFICANCE

Plasma chemokine concentrations are associated with the presence and extent of spontaneously visible coronary artery collaterals and may be mechanistically involved in their recruitment.

Poor coronary collateral vessel development in patients with mild to moderate renal insufficiency

BACKGROUND

The development of coronary collaterals is crucial to survival through acute ischemia. Mild to moderate loss of renal function has been suggested to play a role in this event, but evidential data are scarce. The aim of this study was to investigate the relationship between mild to moderate renal insufficiency and coronary collateral development in patients with chronic total coronary artery occlusion.

METHODS AND RESULTS

A total of 83 patients with mild to moderate loss of renal function (30 mL/min/1.73 m(2) ≤ eGFR < 90 mL/min/1.73 m(2)) with chronic total coronary artery occlusion were included in our study. The collateral circulation was graded according to Rentrop classification and the function of collateral circulation was graded according to Werner collateral connection (CC) grades. Compared to patients with good collateral circulation (Rentrop = 2,3), eGFR was found to be lower in those patients with poor coronary collateral circulation (Rentrop = 0,1) (63.30 ± 10.51 vs. 54.13 ± 10.56, P = 0.02). eGFR was also found to be lower in poorly functioning coronary collateral circulation (CC = 0,1) than in efficiently functioning coronary collateral circulation (CC = 2) (55.22 ± 9.98 vs. 66.28 ± 9.16, P = 0.03). Multiple logistic regression analysis showed that low eGFR was independently associated with poor coronary collateral circulation (Rentrop = 0,1, 95% CI, 0.09-1.09, P = 0.044) and poor function of coronary collateral circulation (CC = 0,1, 95% CI, 0.02-0.17, P = 0.02).

CONCLUSIONS

Lower eGFR is associated with poorer coronary collateral vessel development in patients experiencing mild to moderate renal insufficiency. Moreover, eGFR represents an independent factor affecting coronary collateral vessel development.

Impact of collateral flow to the occluded infarct-related artery on clinical outcomes in patients with recent myocardial infarction: a report from the randomized occluded artery trial

BACKGROUND

Collateral flow to the infarct artery territory after acute myocardial infarction may be associated with improved clinical outcomes and may also impact the benefit of subsequent recanalization of an occluded infarct-related artery.

METHODS AND RESULTS

To understand the association between baseline collateral flow to the infarct territory on clinical outcomes and its interaction with percutaneous coronary intervention of an occluded infarct artery, long-term outcomes in 2173 patients with total occlusion of the infarct artery 3 to 28 days after myocardial infarction from the randomized Occluded Artery Trial were analyzed according to angiographic collaterals documented at study entry. There were important differences in baseline clinical and angiographic characteristics as a function of collateral grade, with generally lower-risk characteristics associated with higher collateral grade. Higher collateral grade was associated with lower rates of death (P=0.009), class III and IV heart failure (P<0.0001) or either (P=0.0002) but had no association with the risk of reinfarction. However, by multivariate analysis, collateral flow was neither an independent predictor of death nor of the primary end point of the trial (composite of death, reinfarction, or class IV heart failure). There was no interaction between angiographic collateral grade and the results of randomized treatment assignment (percutaneous coronary intervention or medical therapy alone) on clinical outcomes.

CONCLUSIONS

In recent myocardial infarction, angiographic collaterals to the occluded infarct artery are correlates but not independent predictors of major clinical outcomes. Late recanalization of the infarct artery in addition to medical therapy shows no benefit compared with medical therapy alone, regardless of the presence or absence of collaterals. Therefore, revascularization decisions in patients with recent myocardial infarction should not be based on the presence or grade of angiographic collaterals. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00004562.

The relation between endothelial dependent flow mediated dilation of the brachial artery and coronary collateral development - a cross sectional study

BACKGROUND

Endothelial dysfunction is thought to be a potential mechanism for the decreased presence of coronary collaterals. The aim of the study was to investigate the association between systemic endothelial function and the extent of coronary collaterals.

METHODS

We investigated the association between endothelial function assessed via flow mediated dilation (FMD) of the brachial artery following reactive hyperemia and the extent of coronary collaterals graded from 0 to 3 according to Rentrop classification in a cohort of 171 consecutive patients who had high grade coronary stenosis or occlusion on their angiograms.

RESULTS

Mean age was 61 years and 75% were males. Of the 171 patients 88 (51%) had well developed collaterals (grades of 2 or 3) whereas 83 (49%) had impaired collateral development (grades of 0 or 1). Patients with poor collaterals were significantly more likely to have diabetes (p = 0.001), but less likely to have used statins (p = 0.083). FMD measurements were not significantly different among good and poor collateral groups (11.5 +/- 5.6 vs. 10.4 +/- 6.2% respectively, p = 0.214). Nitroglycerin mediated dilation was also similar (13.4 +/- 5.9 vs. 12.8 +/- 6.5%, p = 0.521).

CONCLUSION

No significant association was found between the extent of angiographically visible coronary collaterals and systemic endothelial function assessed by FMD of the brachial artery.

The effect of thrombolytic therapy on left ventricular aneurysm formation in acute myocardial infarction: relationship to successful reperfusion and vessel patency

BACKGROUND

Although there is increasing evidence for the beneficial effect of thrombolytic therapy on global left ventricular (LV) function in acute myocardial infarction (AMI), the data concerning the early effect of thrombolytic therapy on the incidence of left ventricular aneurysm (LVA) formation and its relationship to clinical and angiographic determinants are limited.

HYPOTHESIS

The study aimed to determine the independent factors involved in the development of LVA and to evaluate whether thrombolytic therapy has any preventive effect on the development of LVA in AMI.

METHODS

In all, 350 consecutive patients suffering from a first attack of AMI were included. Of these, 205 who arrived within 12 h of onset of symptoms received thrombolytic therapy (thrombolytic group) and the remaining 145 patients served as control group. All patients received aspirin and maximal-dose anticoagulation with intravenous heparin therapy. Early successful reperfusion was assessed by enzymatic and electrocardiographic evidence, and late vessel patency was evaluated according to Thrombolysis in Myocardial Infarction (TIMI) classification. Patients with TIMI grade 2 or 3 flow were considered to have vessel patency.

RESULTS

The overall incidence of LVA was 11.7% (41/350), and no statistical difference was found between the incidence of LVA between the two groups (11.7 vs. 11.7%, p>0.05). However, the patients receiving thrombolytic therapy and exhibiting a patent infarct-related artery (PIRA) (n = 125, 61%), had a significantly reduced incidence of LVA compared with those who did not (7.2 vs. 18.8%, p= 0.015). In univariate analysis, vessel patency, proximal left anterior descending artery (LAD) stenosis, total LAD occlusion, multivessel disease, and hypertension were found to be important factors in LVA formation after AMI. After adjustment for other clinical and angiographic variables, total LAD occlusion (odds ratio [OR] 3.62,95% confidence interval [CI] 2.45-8.42, p = 0.0014), absence of PIRA (OR 2.92, 95% CI 1.41-09, p = 0.0037) and proximal LAD stenosis (OR 2.11, 95% CI 1.05-4.71, p = 0.045) remained the independent determinants of LVA formation after AMI.

CONCLUSION

Our data indicate that not all patients who received thrombolytic therapy, but only those with PIRA had evidently reduced the incidence of LVA. Patients with total LAD occlusion, with proximal LAD stenosis, and without PIRA were found to have increased risk for formation of LVA after AMI. These findings indicate that the presence of vessel patency has a preventive effect on LVA formation in AMI.

Appraising the pathophysiologic impact of coronary collaterals as measured by fractional flow reserve on symptoms and signs of myocardial ischemia

BACKGROUND

The purpose of coronary revascularization in stable patients is anginal relief, yet there is no linear relationship between stenosis severity and clinical significance. A major factor in this complex lesion-myocardium interaction is collateral flow. We aimed to define which collateral flow cut-offs separate asymptomatic from symptomatic patients during coronary occlusion.

METHODS

Patients undergoing percutaneous transluminal coronary angioplasty for a single stenotic lesion were selected, collaterals were appraised angiographically, and fractional flow reserve was used during prolonged balloon occlusion to measure collateral flow index (FFRcoll). Changes in anginal symptoms, ST-T segment, and left ventricular wall motion were appraised before and during/shortly after balloon dilation. Receiver-operating-characteristic curves and area under the curve were computed to identify the most appropriate FFRcoll cut-offs.

RESULTS

Twenty consecutive patients were enrolled. At baseline, 10 patients had angiographic evidence of collaterals, whereas 10 had no angiographic evidence of collateral flow distal to the target lesion. FFRcoll had an excellent discriminatory performance for the presence of angiographic collaterals (area under the curve = 0.90, P = 0.003), a good discriminatory performance for the occurrence of angina (area under the curve = 0.80, P = 0.025), and a trend toward a good discriminatory performance for the occurrence of asynergy (area under the curve = 0.81, P = 0.06). On the basis of receiver-operating-characteristic curves, an FFRcoll cut-off greater than 0.26 could reliably distinguish patients with adequate collaterals (sensitivity = 0.90, specificity = 0.80), whereas a greater than 0.41 cut-off distinguished patients having angina or wall motion abnormalities from those remaining asymptomatic.

CONCLUSION

This study shows that distal collateral pressure greater than 41% of proximal perfusion pressure protects from anginal symptoms or regional systolic dysfunction during coronary occlusion, whereas a greater than 26% cut-off is more appropriate to identify angiographically evident collaterals ensuring distal myocardial viability.

Coronary collaterals improve prognosis in patients with ischemic heart disease

BACKGROUND

The recruitment of coronary collateral vessels results from an endogenous adaptation to ischemic heart disease (IHD). Presence of collaterals may exert protection at the time of acute or chronic obstructive coronary disease. The protective role of collaterals in patients with extensive coronary artery disease however, has been disputed. We examined the effects of coronary collateral circulation on cardiovascular outcomes, with an emphasis on clinical prognostic value and on a putative role of IHD burden.

METHODS

Data analyzed were obtained in the REGRESS study, involving 879 male participants undergoing coronary angiography and being followed for 24 months. Presence of coronary collaterals spontaneously visible on angiography was assessed. Events included: myocardial infarction (MI), coronary heart disease death and percutaneous or surgical coronary intervention. Estimates of relative risks of outcome events were calculated using proportional hazard analysis, with adjustments for confounding factors and stratification for initial revascularization strategy and factors reflecting extent of IHD burden.

RESULTS

Event-free survival after two years was 84% in patients without collaterals, and 92% in patients with collaterals (p=0.0020). The crude HR was 0.48 (95% CI: 0.30-0.77), and 0.38 (0.23-0.65) after adjustment for confounders and cardiovascular risk factors. The protective effect of coronary collaterals was not modified by the extent of IHD burden (interaction p=0.99).

CONCLUSION

The angiographical presence of coronary collaterals is a clinical predictor of cardiovascular prognosis. Collaterals exert a protective effect on outcome in a broad spectrum of patients. Our data suggest that this protective effect is independent of disease burden, and remains present in patients with extensive IHD.

Relationship Between Aortic Stiffness and the Development of Coronary Collateral in Patients With Coronary Artery Disease

Large artery stiffness is an independent predictor of cardiovascular mortality and a major determinant of pulse pressure. The stiff aorta may result in greater systolic, lower diastolic, and wider pulse pressures, which may decrease coronary artery perfusion. Shear stress has been implicated in the development of coronary collateral. Decreased coronary perfusion may reduce shear stress and thus collateral formation. The goal of this study was to assess the relationship between the development of coronary collateral and aortic stiffness in patients with coronary artery disease. In 106 patients with at least one coronary artery stenosis of 90% or greater, collateral vessels were assessed angiographically by the Rentrop grading (grade 0—3), establishing two groups: 50 patients with poor collateral vessels (Rentrop grade 0 or 1), and 56 patients with good collateral vessels (Rentrop grade 2 or 3). Internal aortic root diameters were measured at 3 cm above the aortic valve by use of two-dimensional guided M-mode transthoracic echocardiography, and arterial pressure was measured simultaneously at the brachial artery by sphygmomanometry. Two indexes of the aortic elastic properties were measured: aortic distensibility index was calculated by use of the formula: 2 × (systolic diameter — diastolic diameter)/(diastolic diameter) × (pulse pressure) in cm— 2dyn—110—6. The aortic stiffness index was calculated by: (systolic blood pressure/diastolic blood pressure)/pulsatile change in diameter/diastolic diameter. The aortic distensibility index and the aortic stiffness index were not significantly different between the patients with poor collateral vessels and those with good collateral vessels (5.1 ±2.3 vs 5.7 ±3.3 cm—2dyn —110—6, p = 0.31; 4.02 ±2.3 vs 4.43 ±3.7, p = 0.49, respectively). There were no significant differences regarding the aortic elastic properties between the patients with poor collateral vessels and those with good collateral vessels, suggesting that collateral formation is a complex phenomenon consisting of several distinct processes.

Surgery for myocardial salvage in acute myocardial infarction and acute coronary syndromes

This article addresses the pathophysiology, the treatment options, and their rationale in the setting of life-threatening acute myocardial infarction and acute on chronic ischemia. Although biases may exist between cardiologists and surgeons, with this review, we hope to provide the reader with information that will shed light on the options that best suit the individual patient in a given set of circumstances.

Sympathetic overactivity in patients with left ventricular aneurysm in early period after anterior myocardial infarction: does sympathetic activity predict aneurysm formation?

Left ventricular aneurysm (LVA) is an important complication of acute transmural myocardial infarction (MI) that bears great clinical significance because of high mortality. Heart rate variability (HRV) analysis is extensively used to evaluate autonomic modulation of sinus node and to identify patients at risk for an increased cardiac mortality. In this study, the authors evaluated HRV in patients with LVA in the early period after acute anterior wall MI. They compared 18 patients (7 men, 11 women, with an average age of 56.1 +/-8.2 years) with LVA and 46 patients (34 men, 12 women, with an average age of 56.4 +/-5.9 years) without LVA. Mean heart rate, low frequency (LF) and low-frequency/high-frequency (LF/HF) ratio were significantly higher and standard deviation of normal-to-normal RR intervals (SDNN), root mean square of successive differences (RMSSD), number of NN intervals that differed by more than 50 ms from adjacent interval divided by the total number of all NN intervals (PNN50), and HF were lower in the patients with LVA. A SDNN <78 ms separated the patients with aneurysm from those without aneurysm with a sensitivity of 78%, specificity of 83%, positive predictive accuracy of 79%; a LF/HF ratio >2.4 with a sensitivity of 92%, specificity of 88%, and positive predictive accuracy of 92%. Single-vessel disease increased the left ventricular aneurysm formation by 5.1 fold, total left anterior descending artery (LAD) occlusion by 3.1 fold, mean heart rate >75 beats/minute by 2.3 fold, SDNN <78 ms by 7.9 fold, and LF/HF ratio >2.4 by 12.9 fold, but well-developed collaterals decreased the aneurysm formation by 4.4 fold. As a result, HRV analysis supplies parameters with high predictive value for LVA formation in the early period after acute anterior MI. The higher sympathetic activity and reduced heart rate variability may be associated with a higher incidence of complications such as ventricular arrhythmias and increased mortality in patients with LVA.

Coronary collaterals—insights in molecular determinants and prognostic relevance

In the field of molecular cardiology, recently several determinants of coronary collateral circulation have been identified. Knowing these factors may aid risk-stratification and put forward targets for intervention by stimulating development of collateral blood vessels (arteriogenesis). However, prognostic importance of coronary collaterals is not yet beyond debate, and seems to be modified by the extent of atherosclerotic burden. Combining these insights is essential to increase our understanding of these mechanisms and to proceed with developing strategies for risk-stratification and therapeutic stimulation of arteriogenesis.

Impact of coronary collateral circulation on QT dispersion in patients with coronary artery disease

OBJECTIVE

The aim of this study was to assess the effect of coronary collateral circulation (CCC) on QT dispersion (QTD) in coronary artery disease.

BACKGROUND

A prolonged QTD has been linked to increased heterogeneity of ventricular repolarization implicated in the genesis of ventricular arrhythmias and has been associated with an adverse prognosis in patients with coronary artery disease.

METHOD

CCC and corrected QTD (QTcD) were established in patients who had at least 85% stenosis in the left anterior descending coronary artery or in proximal part or in the body of the right coronary artery. Furthermore, left ventricular function score was determined for all the patients.

RESULTS

While CCC was not present (CCC grade 0) in 32 patients, 68 patients were observed with CCC (CCC grade > or =1). Mean QTcD was higher in patients who had CCC grade > or =1 than in patients with grade 0 (64.3+/-3.5 and 46.8+/-2.7, respectively, P=0.002). We detected a significant correlation between the collateral score and QTcD (r=0.354, P=0.001). CCC grade > or =1 patients had higher mean left ventricular function scores than grade 0 patients (P=0.048). Left ventricular function score and QTcD were observed to be correlated (r=0.200, P=0.046).

CONCLUSION

CCC in chronic coronary artery disease was not established to have a positive decreasing effect on QTcD. On the contrary, QTcD values were observed to be even higher in patients with well developed CCC. Further research including larger series and long-term follow-up is required to investigate this issue.

Assessment of collateralized myocardium with Cardiac Magnetic Resonance (CMR): transmural extent of infarction but not angiographic collateral vessel filling determines regional function and perfusion in collateral-dependent myocardium

BACKGROUND

Angiographic collateral vessel filling is limited to evaluate collateral-dependent myocardium. We hypothesize, that quantitative assessment of regional myocardial function, perfusion and viability with Cardiac Magnetic Resonance (CMR) adds complementary information to angiography of collateralized myocardium.

METHODS

CMR was performed in 30 patients with one chronic occluded coronary artery and no further flow limiting stenosis to assess transmural extend of infarction (TEI), resting perfusion and perfusion during adenosine-induced hyperemia and regional wall thickening (RWT) in collateral-dependent and antegradely-perfused myocardium. Collateral vessels were evaluated by angiography and the Rentrop grade (0-3).

RESULTS

In 15 patients with < 50% TEI in collateral-dependent myocardium resting perfusion (1.08+/-0.22 ml/min/g), hyperemia (2.21+/-0.73 ml/min/g) and RWT (4.0+/-2.6 mm) were similar to antegradely-perfused myocardium (rest 1.14+/-0.20 and hyperemia 2.46+/-0.82 ml/min/g, RWT 4.3+/-1.7 mm). In 15 patients with > or = 50% TEI in collateral-dependent myocardium resting perfusion and hyperemia as well as RWT were significantly lower (rest 0.84+/-0.19, p<0.001 and hyperemia 1.34+/-0.43 ml/min/g, p<0.001; RWT 1.0+/-1.0 mm, p<0.0001) compared to antegradely-perfused myocardium. There was an inverse correlation between TEI and resting or hyperemic perfusion or RWT. In contrary, resting perfusion and hyperemia as well as RWT in collateral-dependent myocardium were not different between patients with good (2-3) compared to patients with poor Rentrop grade (0-1). There was no correlation between TEI and Rentrop grade.

CONCLUSION

Function and perfusion in collateral-dependent myocardium are preserved, if transmural extent of infarction is limited (< 50%). This is independent of their angiographic collateral vessel filling. Thus, CMR adds complementary information to angiographic standard assessment of collateral vessels.

Usefulness of plasma brain natriuretic peptide concentration for predicting subsequent left ventricular remodeling after coronary angioplasty in patients with acute myocardial infarction

To determine the relation between plasma brain natriuretic peptide (BNP) and remodeling in terms of infarct-related artery (IRA) patency, 106 patients with a first anterior wall acute myocardial infarction with a patent IRA at 1 month were studied. The IRA reoccluded at 6 months in 17 patients (reoccluded IRA) and was patent in 89 patients (patent IRA). The 2 groups did not differ with respect to clinical characteristics, hemodynamic variables, and left ventricular function at 1 month, except for left ventricular end-diastolic and systolic volumes, which were significantly greater in the reoccluded IRA group. Plasma BNP concentration in the reoccluded IRA group (336 +/- 288 pg/ml) was significantly higher than that in the patent IRA group (116 +/- 106 pg/ml) at 1 month. BNP concentration decreased significantly at 6 months in the 2 groups (reoccluded IRA vs patent IRA 152 +/- 162 vs 44 +/- 58 pg/ml, p <0.05). The increase in left ventricular volume from 1 to 6 months was significantly correlated with plasma BNP concentration at 1 month in the patent IRA group (r = 0.314, p < 0.01) and the reoccluded group (r = 0.634, p < 0.01). Linear regression analysis showed that the correlation between the 2 parameters in the 2 groups was similar. Based on stepwise multivariate linear regression analysis, only plasma BNP concentration was significantly correlated with the increase in left ventricular volume from 1 to 6 months in the 2 groups. In conclusion, these results suggest that plasma BNP concentration predicts left ventricular dilation independently of IRA patency.

Determinants and prognostic significance of collaterals in patients undergoing coronary revascularization

There is evidence that coronary collaterals improve the prognosis in patients with acute myocardial infarction (MI). However, there is limited clinical information on the protective role of collaterals in patients with stable coronary artery disease. This information may help risk stratification and the development of novel therapies, such as arteriogenesis and angiogenesis. The relation between collaterals and cardiac death or MI at 1 year after coronary revascularization was studied in 561 patients who were enrolled in a randomized study that compared stent implantation with bypass grafting. Collaterals were assessed on an angiogram using Rentrop's classification and considered present with a Rentrop grade >1. Unadjusted and adjusted odds ratios for cardiac death or MI at 1 year were calculated using univariate and multivariate regression analyses. In addition, determinants of collaterals were assessed using univariate and multivariate analyses. Collaterals were present in 176 patients (31%). The adjusted odds ratio of cardiac death or infarction was 0.18 (95% confidence interval 0.04 to 0.78) in the presence of collaterals. Independent determinants of collaterals were age (odds ratio 0.97, 95% confidence interval 0.95 to 0.99), multivessel disease (odds ratio 1.60, 95% confidence interval 1.02 to 2.51), impaired ventricular function (odds ratio 1.85, 95% confidence interval 1.04 to 3.29), type C lesion (odds ratio 3.72, 95% confidence interval 2.33 to 5.95), and stenosis severity >90% (odds ratio 9.08, 95% confidence interval 4.65 to 17.73). In conclusion, in patients with a low risk profile, the presence of collaterals protects against cardiac death and MI at 1 year after coronary revascularization. Variables that reflect the duration and severity of the atherosclerotic and ischemic burden determine their presence.

Significant correlation of recruitable coronary collateral blood flow determined by coronary wedge pressure with ST-segment elevation during coronary occlusion

OBJECTIVES

Quantitative assessment of coronary collateral blood flow can be archived by measuring coronary pressure. We studied the relationships between recruitable coronary collateral blood flow and electrocardiographic changes during percutaneous coronary intervention (PCI).

METHODS

We measured coronary pressure during coronary occlusion with PCI in 119 patients with left anterior descending coronary artery stenosis. During balloon inflation, the electrocardiogram was continuously recorded. The ST-segment elevation in the most elevated lead was defined as MaxST and the sum of the maximal ST elevation in leads V2-V4 was defined as sumST. Fractional collateral flow (Qc/Q(N)) was calculated as the coronary wedge pressure divided by the mean aortic pressure. Myocardial ischemia was defined as an ST-segment shift >0.1 mV in any of the V2, V3 or V4 leads.

RESULTS

A significant relationship between Qc/Q(N) and MaxST was observed (r=-0.455, P<0.0001). Similarly, Qc/Q(N) was significantly correlated with sumST (r=-0.477, P<0.0001). The receiver operating characteristic curve showed that a cut-off value of 0.27 for Qc/Q(N), with sensitivity of 71.4% and specificity of 76.2%, was an indicator of electrophysiologically sufficient recruitable coronary collateral blood flow for prevention of ischemia during coronary obstruction. Qc/Q(N) values during the first, second, third and fourth inflation were not significantly different.

CONCLUSIONS

Qc/Q(N) could be clinically useful for determining whether there is electrophysiologically sufficient recruitable coronary collateral blood flow for prevention of ischemia during coronary obstruction. Repeat transient coronary occlusion during PCI did not lead to increased collateral blood flow.