Influence on collateral flow of recanalising chronic total coronary occlusions: a case-control study

Relationship of mean platelet volume to lymphocyte ratio and coronary collateral circulation in patients with stable angina pectoris

BACKGROUND

In patients with coronary artery disease, coronary collateral circulation (CCC) develops as an adaptation to ischemia and contributes toward reduction of cardiovascular events. Recently, the mean platelet volume-to-lymphocyte ratio (MPVLR) has emerged as a novel and readily available marker of inflammation and thrombosis. This study aimed to investigate the relationship between MPVLR and development of CCC.

PATIENTS AND METHODS

A total of 332 patients with stable angina pectoris undergoing coronary arteriography were enrolled and divided on the basis of the development of CCC into two groups: group with adequate CCC (n=243) and group with impaired CCC (n=89). Routine complete blood count parameters and high-sensitivity C-reactive protein (hsCRP) were measured before coronary arteriography.

RESULTS

Both MPVLR and hsCRP levels were higher in the impaired CCC group (P<0.001 and P=0.007, respectively). Multivariate logistic regression analysis indicated that MPVLR was associated independently with impaired CCC [odds ratio (OR): 1.706, 95% confidence interval (CI): 1.328-2.192, P<0.001]. In addition to MPVLR, hsCRP (OR: 1.144, P=0.030) and fasting blood glucose (OR: 1.007, P=0.049) were also associated independently with impaired CCC. In receiver operating characteristics curve analysis, an optimal cut-off point for MPVLR (4.47) was found to predict the presence of good CCC with a sensitivity of 75.3% and a specificity of 71.2% (P<0001).

CONCLUSION

Our findings suggest that measurement of MPVLR may predict the development of CCC in patients with stable coronary artery disease. An increased MPVLR is associated independently with impaired CCC in these patients.

Endocan Levels and Coronary Collateral Circulation in Stable Angina Pectoris: A Pilot Study

We investigated the relationship between endocan (a marker of systemic inflammation) and the development of coronary collateral circulation (CCC) as evaluated by coronary angiography in patients with chronic stable angina pectoris. A total of 90 patients (32 poor CCC and 58 good CCC) were included in this study. Endocan levels were determined using a commercially available sandwich enzyme-linked immunosorbent assay kit with high sensitivity and specificity for detection of human endocan. In multivariate logistic regression analysis, low endocan levels were independently associated with good CCC ( P < .001). Moreover, low high-sensitivity C-reactive protein levels were also independently associated with good CCC ( P = .020). We found an optimal cutoff point for endocan of 1.7 ng/mL; it predicted the presence of good CCC with a sensitivity of 72.4% and specificity of 65.6% ( P < .001). The results of the present study suggest that measurement of endocan level may help clinicians to predict the development of CCC in patients with stable coronary artery disease.

Pathophysiology of coronary collaterals

While the existence of structural adaptation of coronary anastomoses is undisputed, the potential of coronary collaterals to be capable of functional adaptation has been questioned. For many years, collateral vessels were thought to be rigid tubes allowing only limited blood flow governed by the pressure gradient across them. This concept was consistent with the notion that although collaterals could provide adequate blood flow to maintain resting levels, they would be unable to increase blood flow sufficiently in situations of increased myocardial oxygen demand.

However, more recent studies have demonstrated the capability of the collateral circulation to deliver sufficient blood flow even during exertion or pharmacologic stress. Moreover, it has been shown that increases in collateral flow could be attributed directly to collateral vasomotion.

This review summarizes the pathophysiology of the coronary collateral circulation, ie the functional adapation of coronary collaterals to acute alterations in the coronary circulation.

The collateral circulation of the heart in coronary total arterial occlusions in man: systematic review of assessment and pathophysiology

BACKGROUND

Anatomical and functional assessment of the collateral circulation of the heart in total arterial occlusions is challenging, and this is particularly true of the microcirculation. The pathophysiology of the collateral circulation has historically been and remains of considerable research focus but with diverging and sometimes conflicting results. Our purpose was to conduct a systematic review on the assessment and pathophysiology of the collateral circulation of the heart in total coronary arterial occlusions.

METHODS

We extracted data from Pubmed, Ovid, EMBASE, and Cochrane database from 1966 to December 2012. Two investigators independently reviewed the identified articles for eligibility and extracted the data.

RESULTS

Seventy-seven studies met inclusion criterion. An invasive assessment of the collateral circulation with pressure and/or Doppler wires is the gold standard in the assessment of collateral physiology and anatomy, although this can only be undertaken after successful passage of the sensor in the true lumen of the occluded vessel. A collateral circulation can provide resting metabolic requirements for the heart but invariably cannot meet demands on stress irrespective of the degree of collateralization as assessed by coronary angiography. In the case of myocardium subtending a totally occluded epicardial artery coronary collateral grading systems or physiological assessment of collateral flow is only moderately sensitive and poorly specific at predicting viability. Regression of collaterals seems more profound in totally occluded arteries versus nonoccluded lesions postrevascularization.

CONCLUSIONS

Key controversies in the assessment and pathophysiology of the collateral circulation of the heart in total coronary arterial occlusions are systematically evaluated.

The relation of platelet-lymphocyte ratio and coronary collateral circulation in patients with stable angina pectoris and chronic total occlusion

OBJECTIVES

We aimed to investigate the relationship between the platelet-lymphocyte ratio (PLR) and coronary collateral circulation (CCC) in patients with stable angina pectoris (SAP) and chronic total occlusion (CTO).

METHODS

A total of 294 patients with both SAP and CTO were classified according to their Rentrop collateral grades as either poor (Rentrop grades/0-1) or good (Rentrop grades/2-3).

RESULTS

The PLR values were significantly higher in patients with poor CCC than in those with good CCC (156.8 + 30.7 vs 132.1 + 24.4, P < 0.001). In regression analysis, PLR (unit = 10) [odds ratio 1.48, 95% confidence interval (CI) 1.33 -1.65; P < 0.001] and high-sensitivity C-reactive protein were found to be the independent predictors of poor CCC. In receiver operator characteristic curve analysis, optimal cut-off value of PLR to predict poor CCC was found as 138.1, with 76% sensitivity and 65% specificity.

CONCLUSION

PLR may be an important, simple, and cost effective tool predicting the degree of collateralization in patients with SAP and CTO.

The relationship between diastolic pressure and coronary collateral circulation in patients with stable angina pectoris and chronic total occlusion

BACKGROUND

The most important biomechanical source of activation of the coronary collateral circulation (CCC) is increased tangential fluid shear stress at the arterial endothelial surface. The coronary circulation is unique in that most coronary blood flow occurs in diastole. Consequently, the diastolic blood pressure (DBP) may influence the tangential fluid shear stress on the arterial endothelial surface in diastole, therebyaffecting development of the CCC.

METHODS

To investigate this, we conducted a study of 222 patients with stable angina pectoris and chronic total occlusion of coronary arteries. All of the patients had no history of coronary artery interventional therapy, coronary artery bypass surgery, cardiomyopathy, or congenital heart disease. The extent of the collateral vasculature of the area perfused by the artery affected by chronic total occlusion was graded as poor or well-developed according to Rentrop's classification.

RESULTS

Univariate analysis showed a significant difference between the study subgroup with poorly developed collaterals and that with well-developed collaterals in terms of high diastolic blood pressure (DBP) and mean DBP. Multivariate analysis revealed high DBP as the only independent positive predictor of a well-developed collateral circulation.

CONCLUSIONS

High DBP is positively related to a well-developed CCC. Differences in development of the CCC may be one of the pathophysiologic mechanisms responsible for the J-curve phenomenon in the relationship between DBP and cardiovascular risk.

Coronary Collaterals Remain Recruitable After Percutaneous Intervention

Background— Rapid loss of collateral support has been reported after percutaneous coronary intervention (PCI), leaving the myocardium susceptible to subsequent infarction. However, well-developed collaterals have been found in normal hearts, suggesting that collaterals exist even in the absence of an ischemic stimulus. We assessed the plasticity and determinants of collateral supply after PCI.

Methods and Results— Collateral flow index (CFI) was calculated in 60 patients as (P w −P v )/(P a −P v ) by measurement of aortic (P a ), central venous (P v ), and coronary wedge (P w ) pressures. CFI was reassessed during transient balloon occlusion 5 minutes and 24 hours after PCI in the first 29 patients and at 6 months in the subsequent 25 patients. We also evaluated the relationship between collateral supply, lesion characteristics, and circulating hemopoietic cells numbers before and after successful PCI. CFI at baseline was 0.23±0.10, with no change 5 minutes and 1 day later (0.21±0.12, P =0.62; and 0.22±0.11, P =0.96, respectively). At 6 months, CFI was 0.14±0.07 or 63±27% of the baseline value ( P <0.001). CFI was proportional to severity of the coronary lesion at baseline ( r =0.63, P <0.0001) but not 6 months after PCI ( r =−0.04, P =0.87). The number of circulating CD133 + and CD34 + cells was associated with CFI 6 months after PCI (CD133, r =0.59, P =0.035; CD34, r =0.63, P =0.037).

Conclusions— Coronary collateral flow remains undiminished for at least 24 hours after successful PCI. Functional collateral support subsequently declines but does not regress completely.

The role of collateral circulation in preserving myocardial function

The coronary collateral circulation is an alternative source of blood supply to the myocardium jeopardized by the failure of the original stenotic or occluded vessel to provide adequate blood flow to this region. One hundred coronary angiograms and left ventriculograms of patients with coronary artery disease from the Cardiology Department of University Clinics Centre in Sarajevo were reviewed. The role of collateral circulation in preserving myocardial function was assessed by comparing regional left ventricular contractility in 34 instances of total arterial occlusion and adequate colateral circulation with that in 34 instances of total arterial occlusion and inadequate collateral circulation. Among the group with adequate collaterals, regional left ventricular contraction was normal in 41%, hypokinetic in 53% and akinetic or dyskinetic in only 5%. Among the group with inadequate collaterals, regional contraction was normal in 9%, hypokinetic in 20 % and akinetic or dyskinetic in 70%. These data indicate that collateral circulation plays an important role in preserving myocardial contractility in patients with coronary artery disease.

Collateral circulation in human heart

The aim of the investigations was to demonstrate different types of collaterals of coronary arteries using the method of coronary angiography and injection-corrosion method. The investigations were carried out on 30 human cadaveric hearts from the Department of Anatomy, and 30 angiograms of patients from the Cardiology Department of Clinics Centre in Sarajevo. Clinical investigations were retrospective and prospective on patients that were treated in hospital, and on patients that just arrived in hospital (based on findings of coronary angiography). The results show the existence of different types of collaterals: intercoronary and intracoronary. We established collaterals in a case with occlusion of the right coronary artery and left coronary artery in which better development of collaterals was established. Our patients were classified in two groups: 1) Patients with good collaterals and good left ventricular function; 2) Patients with good collaterals and impaired left ventricular function. On the anatomical material we found different types of collaterals as well. Our results show that coronary angiography is useful diagnostic method for the demonstration of coronary collaterals.

Collateralization and the response to obstruction of epicardial coronary arteries

Occlusive coronary disease is an important cause of global morbidity and mortality. While mechanical revascularization is effective, some individuals are not amenable to such interventions, and have a poorer prognosis. However, collateral circulation can protect and preserve myocardium around the time of coronary occlusion, contribute to better residual myocardial contractility, and lessen symptoms. We describe the anatomy and physiology of coronary collateralization, its component parts (angiogenesis and arteriogenesis), the current methods for definition of the collateral response and how this might be manipulated. The manipulation of this process is a realistic possibility for future adjuvant treatment of coronary artery disease.

Regression of Collateral Function After Recanalization of Chronic Total Coronary Occlusions

BACKGROUND

Collaterals can maintain myocardial function or preserve viability in chronic total coronary occlusions (CTOs). It is unknown whether and to what extent collaterals regress after successful recanalization of a CTO.

METHODS AND RESULTS

In 103 patients with successful recanalization of a CTO collateral function was assessed by intracoronary Doppler and pressure recordings before and after recanalization, and again after 5.0+/-1.3 months. Doppler (CFI) and pressure-derived collateral function indexes (CPI) and collateral (RColl) and peripheral resistance indexes (RP) were calculated. In 10 patients with reocclusion, all without myocardial infarction during follow-up, collateral function had reached a similar level as before the first recanalization. In the other 93 patients with or without restenosis, collateral function was attenuated during follow-up. CPI had decreased by 23% immediately after recanalization (P<0.001) and decreased further by another 23% at follow-up (P<0.001). The RColl increased immediately after recanalization by 82% (P<0.001) and by a further 273% at follow-up (P<0.001). In contrast, RP increased only by 22% after recanalization (P<0.001) and by an additional 12% at follow-up (P<0.05). The initial size of the collaterals but not the incidence of a restenosis influenced the collateral regression. Only 18% of patients at follow-up had collaterals with a CPI >0.30, presumably sufficient to prevent ischemia during acute occlusion.

CONCLUSIONS

Collateral function regresses during long-term follow-up, especially in collaterals with a small diameter. In the majority of patients, collaterals are not readily recruitable in the case of acute occlusion. However, collaterals have the potential to recover in the case of chronic reocclusion.

Angiographic assessment of collateral connections in comparison with invasively determined collateral function in chronic coronary occlusions

BACKGROUND

The evaluation of new therapeutic modalities to induce collateral growth in coronary artery disease require improved methods of angiographic characterization of collaterals, which should be validated by quantitative assessment of collateral function.

METHODS AND RESULTS

In 100 patients with total chronic occlusion of a major coronary artery (duration >2 weeks) collaterals were assessed angiographically by the Rentrop grading, by their anatomic location, and by a new grading of collateral connections (CC grade 0: no continuous connection, CC1: threadlike continuous connection, CC2: side branch-like connection). The interobserver variability was 10%. Collateral function was assessed by Doppler flow (average peak velocity) and pressure recordings distal to the occlusion before recanalization. A collateral resistance index (RColl) was calculated. Recruitable collateral flow was measured during a final balloon inflation >30 minutes after the baseline measurement. The comparison of the anatomic location, the Rentrop, and the collateral connection grade showed only for the latter an independent and significant relation with RColl. CC2 collaterals preserved regional left ventricular function better than did CC1 collaterals and provided a higher collateral flow reserve during adenosine infusion. CC0 collaterals were predominantly observed in recent occlusions of 2 to 4 weeks' duration, with the highest RColl. During balloon reocclusion, recruitable collateral function was best preserved with CC2 and least with CC0.

CONCLUSIONS

The angiographic grading of collateral connections in total chronic occlusions could differentiate collaterals according to their functional capacity to preserve regional left ventricular function and was closely associated with invasively determined parameters of collateral hemodynamics.