Angiographic Collaterals Research Articles

Abstract WP5: Collaterals in the Interventional Management of Stroke (IMS) III Trial

Background: Collateral circulation may exert an influential effect on arterial recanalization, downstream angiographic and tissue reperfusion and ensuing clinical outcomes after revascularization for acute ischemic stroke. Endovascular strategies provide unique opportunity to correlate definitive angiographic measures of collaterals at the time of interventional therapy. We conducted a systematic analysis of collaterals on conventional angiography in the endovascular treatment arm of the Interventional Management of Stroke (IMS) III trial. Methods: Prospective evaluation of angiographic collaterals was conducted via central review of all cases enrolled and treated in the endovascular arm of IMS III. Collateral grade was assessed with the ASITN/SIR scale on angiography at procedure start and immediately prior to intra-arterial treatment (time 0), blind to all other data. Statistical analyses investigated the association between collateral grade with baseline clinical data, angiographic measures of recanalization (AOL), angiographic reperfusion (TICI), and clinical outcomes. Results: From 2006-2012, 380 cases were prospectively evaluated for collateral grade at start of procedure and time 0 prior to treatment. Adequate collateral views were available in 283/380 (75%) cases at baseline, and 277/380 (73%) cases at time 0 and after subsequent treatment with intra-arterial tPA, EKOS, MERCI, Penumbra, and Solitaire devices. Detailed results will be presented at ISC in coordination with release of the primary trial results. The relationships between collateral flow grade and baseline clinical features (NIHSS and age), location of vascular occlusion at cerebral angiography, AOL recanalization and TICI reperfusion, and mROS of 0-2 at 90 days will be presented. Analyses will explore potential interactions between collateral flow grade with recanalization, angiographic reperfusion, and clinical outcome. Conclusions: Collateral circulation was available and prospectively evaluated in the largest endovascular therapy trial for stroke conducted to date. The role of collaterals may be an important consideration in the design of future endovascular trials.

Angiographic Features, Collaterals, and Infarct Topography of Symptomatic Occlusive Radiation Vasculopathy

Occlusive radiation vasculopathy (ORV) predisposes head-and-neck cancer survivors to ischemic strokes. We analyzed the digital subtraction angiography acquired in 96 patients who had first-ever transient ischemic attack or ischemic strokes attributed to ORV. Another age-matched 115 patients who had no radiotherapy but symptomatic high-grade (>70%) carotid stenoses were enrolled as referent subjects. Digital subtraction angiography was performed within 2 months from stroke onset and delineated carotid and vertebrobasilar circulations from aortic arch up to intracranial branches. Two reviewers blinded to group assignment recorded all vascular lesions, collateral status, and infarct pattern. ORV patients had less atherosclerotic risk factors at presentation. In referent patients, high-grade stenoses were mostly focal at the proximal internal carotid artery. In contrast, high-grade ORV lesions diffusely involved the common carotid artery and internal carotid artery and were more frequently bilateral (54% versus 22%), tandem (23% versus 10%), associated with complete occlusion in one or both carotid arteries (30% versus 9%), vertebral artery (VA) steno-occlusions (28% versus 16%), and external carotid artery stenosis (19% versus 5%) (all P<0.05). With comparable rates of vascular anomaly, ORV patients showed more established collateral circulations through leptomeningeal arteries, anterior communicating artery, posterior communicating artery, suboccipital/costocervical artery, and retrograde flow in ophthalmic artery. In terms of infarct topography, the frequencies of cortical or subcortical watershed infarcts were similar in both groups. ORV angiographic features and corresponding collaterals are distinct from atherosclerotic patterns at initial stroke presentation. Clinical decompensation, despite more extensive collateralization, may precipitate stroke in ORV.

Frequency of Myocardial Infarction and Its Relationship to Angiographic Collateral Flow in Territories Supplied by Chronically Occluded Coronary Arteries

Despite complete interruption of antegrade coronary artery flow in the setting of a chronic total occlusion (CTO), clinical recognition of myocardial infarction is often challenging. Using cardiac MRI, we investigated the frequency and extent of myocardial infarction in patients with CTO, and assessed their relationship with regional systolic function and the extent of angiographic collateral flow. We included 170 consecutive patients (median age, 62 years) with angiographically documented CTO. Regional late gadolinium enhancement and wall motion score index were assessed by cardiac MRI with the use of a 17-segment model. Angiographic collateral flow was assessed by the collateral connection grade and the Rentrop score. Evidence of previous myocardial infarction was found in 25% of patients by ECG Q waves, in 69% by regional wall motion abnormality, and in 86% of patients by late gadolinium enhancement. Increased angiographic collateral flow was associated with a lower frequency of Q waves on ECG, and a lower regional wall motion score index, late gadolinium enhancement volume (%), and degree of late gadolinium enhancement transmurality (all P<0.001), as well. The frequency of myocardial infarction in territories subtended by CTO is significantly higher than previously recognized. The degree of myocardial injury downstream epicardial CTO is inversely correlated with the degree of angiographic collaterals.

Abstract 2458: Admission Hyperglycemia Causes Infarct Volume Expansion In Patients With ICA And MCA Occlusion: Association Of Collateral Grade On Cerebral Angiography.

Background: The collateral circulation sustains the ischemic penumbra to limit growth of infarct volume. Recent study showed hyperglycemia was associated with infarct volume expansion in acute ischemic stroke patients. The aim of present study is to investigate whether admission hyperglycemia is related with enlargement of infarct volume and poor outcome based on the collateral circulation grade. Methods: From April 2004 to July 2011, acute ischemic stroke patients with ICA and MCA occlusion on cerebral angiography within 24 h of onset were retrospectively studied. We excluded the patients treated with iv t-PA or endovascular therapy. Hyperglycemia was defined as admitting blood glucose value&gt;140mg/dl. Angiographic collateral was evaluated with the ASITN/SIR collateral flow grading system. Grade 0 to 1 was designated as poor collateral and grade 2 to 4 as good collateral. Infarct volume was measured on admission and follow-up (&lt;7days after admission) diffusion weighted imaging on MRI. We compared Δinfarct volume (follow-up-baseline) and patient outcome between hyperglycemic (HG) group and non-HG group according to each collateral grade. Results: 93 patients (65 males, 67.7±13.3 years old, ICA occlusion in 52 and MCA in 41 patients) were enrolled in the present study. Collateral grade was poor in 34 patients (36.6%) and good in 59 patients (63.4%).In poor collateral grade (16 patients in HG group and 18 patients in non-HG group) , there was no significant difference in baseline infarct volume (66.2±93.7 mL vs. 61.8±81.5 mL, P=0.746). However, Δinfarct volume was markedly larger in HG group than non-HG group (106.0±101.4 mL vs. 22.7±54.9 mL, P=0.002). Poor outcome (mRS 5 to 6) at discharge was more frequent in HG group than non-HG group, but the differences were not significantly (56.3% vs. 27.8%, P=0.163). In good collateral grade (34 patients in HG group and 25 patients in non-HG group), the baseline infarct volume did not differ between HG group and non-HD group (17.1±39.2 mL vs. 17.9±37.2 mL, P=0.569). However, Δinfarct volume was more larger in HG group than non-HG group (53.3±74.1 mL vs. 10.9±24.3 mL, P=0.047). Moreover, poor outcome at discharge was frequently observed in HG group than non-HG group (38.2% vs. 12.0%, P=0.038). Conclusion: In patients with ICA and MCA occlusion, admission hyperglycemia should affect infarct volume expansion in poor as well as good collateral circulation.

Abstract 1905: Arterial Spin-Labeled MRI of Leptomeningeal Collateral Perfusion in Acute Ischemic Stroke

Background: Leptomeningeal collaterals and associated cortical perfusion downstream from a proximal arterial occlusion or stenosis are potent predictors of outcome in acute stroke. Arterial spin-labeled (ASL) MRI may depict delayed arterial transit effects (DATE) of these collaterals and cerebral blood flow (CBF), utilizing noninvasive techniques without the use of contrast. We conducted a prospective validation study of ASL DATE and CBF as biomarkers of leptomeningeal collateral perfusion compared to digital subtraction angiography (DSA) and dynamic susceptibility contrast (DSC) perfusion MRI in acute ischemic stroke. Methods: Consecutive anterior circulation acute ischemic stroke patients admitted during a 1-year period were evaluated with pseudo-continuous ASL, DSA and DSC perfusion MRI within 12 hours of symptom onset. ASL DATE extent was scored using a 3-point scale and angiographic collaterals on the DSA graded using the ASITN/SIR collateral score. ASL CBF and DSC CBF maps were co-registered to derive comparative ROI statistics on perfusion in the symptomatic territory. ASL CBF lesions &lt; 15 mL/100 g/min were used to measure DSC CBF values within coregistered ROIs. Results: Among 39 patients meeting entry criteria, mean age was 66±19 years and 51% were male. All 39 patients were imaged with ASL and DSA, with DSC perfusion MRI in a subset of 27. Sites of vascular occlusion or stenosis were: terminal ICA - 10, M1 MCA - 20, M2 MCA - 5 and more distal MCA - 4. ASL DATE scores ranged from 0-2, with a median of 1. DSA collateral grade ranged from 0-4, with a median of 2. Overall, there was strong correlation (r=0.702, p&lt;0.001) between the ASL and DSA measures of leptomeningeal collateral supply. In the downstream territory from these leptomeningeal collaterals, ASL CBF and DSC CBF maps both revealed hypoperfusion in regions that closely matched. Only limited correlation, however, was noted between exact ASL CBF and DSC CBF values within the co-registered ROIs. Conclusions: ASL MRI provides an accurate, noninvasive measure of leptomeningeal collateral perfusion in acute ischemic stroke due to anterior circulation stenosis or occlusion. ASL CBF measures of collateral perfusion likely are arterially weighted, like DSA collateral grades, and unlike conventional DSC perfusion MRI CBF values.

Timing of coronary collateral appearance during ST-elevation myocardial infarction

Objective: The appearance of collaterals during ST-elevation myocardial infarction (STEMI) and clinical factors potentially associated with their early appearance were studied. Background: The appearance of collaterals is associated with the duration of chronic coronary occlusion. Nevertheless, the question remains as to whether collaterals are already apparent shortly after an acute coronary occlusion. Results: The appearance of collaterals was studied during STEMI, in 187 patients who underwent angiography at various times after the onset of symptoms. For the onset-to-angiography groups of 0–6 h, >6–9 h, >9–24 h, >1–7 days, >7–14 days and >14 days, the prevalence of angiographic collaterals (Rentrop classification 2–3) were 19, 31, 41, 40, 50 and 68%, respectively (p < 0.001). Among the clinical factors, preinfarction angina was the only independent determinant (odds ratio 3.1; 95% CI: 1.2–8.5). Conclusion: As in chronic coronary occlusion, after acute occlusion the appearance of angiographic visible co...

Plasma Chemokine Levels Are Associated with the Presence and Extent of Angiographic Coronary Collaterals in Chronic Ischemic Heart Disease

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

Reply to Letter Regarding Article, “The 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”

We are grateful to Drs Meier and Seiler for their comments. This gives us an opportunity to reiterate our interpretation. As already stated in our discussion,1 there is a host of data that demonstrate that the presence of collaterals during acute myocardial infarction is associated with a reduction in infarct size and improved left ventricular function. However, while we agree that coronary collaterals appear to protect the myocardium against ischemia durin g an evolving acute myocardial infarction, the presence of angiographically visible collaterals after the acute phase of myocardial infarction was not an independent predictor of clinical outcomes, once infarction was completed. In addition, there was no interaction between the presence or absence of collaterals and percutaneous coronary intervention (PCI) on the occluded infarct-related artery. Therefore, decisions regarding revascularization of the occluded infarct artery performed after the acute phase should not be based on the presence or absence of angiographically visible …

Leukoaraiosis and collaterals in acute ischemic stroke.

We examined the correlation of angiographic collaterals in acute stroke with the presence, extent, and distribution of white matter changes, so-called Leukoaraiosis, in an effort to determine if Leukoaraiosis indicates chronic cerebral hypoperfusion and/or is associated with the development of cerebral collateral circulation. Consecutive acute strokes due to large-vessel occlusion on angiography had preprocedure CT or MRI white matter changes graded utilizing the Fazekas scale incorporating deep and periventricular components. Angiographic collaterals evaluated with a 5-point scale were correlated with leukoaraiosis. Collaterals were evaluated in 102 cases (51 men, 51 women; mean age 66 (SD 18) years with acute occlusions of the proximal middle cerebral artery (MCA) (47%), distal internal carotid artery (ICA) (28%), distal MCA (9%), basilar (7%), proximal ICA (7%), vertebral (1%), posterior cerebral artery (PCA) (1%), and common carotid artery (CCA) (1%). Collateral grade was well distributed across the scale. Periventricular and deep white matter changes were evident in 34% and 51% of cases, respectively. Collateral grade exhibited no relationship with either the presence or extent of periventricular disease (P= .772, r= .029) or deep white matter changes (P= .559, r=-.059). Leukoaraisosis exhibits no overt relationship with the extent of collaterals measured at angiography in acute ischemic stroke. Chronic small-vessel disease may be a distinct pathophysiologic entity unrelated to arteriogenesis and compensatory aspects of collateral flow.

Assessment of the Human Coronary Collateral Circulation

Cardiovascular disease is the leading cause of death in industrialized countries and may become the most important reason for mortality worldwide.1 In patients suffering from coronary artery disease (CAD), the size of myocardial infarction mainly determines outcome.2 Accordingly, the primary strategy to reduce cardiovascular mortality is by shrinking infarct size (IS) (Figure 1A).3 In the clinical setting of acute myocardial infarction, Antoniucci et al4,5 documented in 1164 patients undergoing primary percutaneous coronary intervention (PCI) that the presence of angiographic collaterals before PCI purported a survival benefit compared with the situation without them (Figure 2). As a surrogate for IS, studies on the effect of myocardial salvage procedures have employed the magnitude of ECG ST-segment elevation during coronary balloon occlusion (Figure 3).6,7 IS, measured as the degree of ECG ST-segment elevation during a 1-minute coronary occlusion, is influenced by the following factors: duration of occlusion, ischemic area at risk for myocardial infarction (AR), collateral blood supply to the ischemic zone, ischemic preconditioning, and myocardial oxygen consumption.8 In the context of a single brief artificial coronary occlusion of uniform duration without preceding bouts of ischemia (Figure 3),6 ECG signs of ischemia are influenced predominantly by the AR and by collateral supply to this region. Furthermore, Figure 1B3 illustrates that AR and collateral supply are inversely related to each other (ie, AR tends to shrink toward zero in the presence of well-functioning collaterals). They are termed sufficient if they prevent an ECG ST-segment elevation of ≥0.1 mV during a 1-minute coronary balloon occlusion; otherwise, they are termed insufficient collaterals. Figure 1. Schematic drawing of the coronary artery circulation without (A) and with interarterial anastomoses (B) between the right coronary artery and the occluded left anterior descending artery (occluded downstream …

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

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. 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. 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.

Angiography Reveals That Fluid-Attenuated Inversion Recovery Vascular Hyperintensities Are Due to Slow Flow, Not Thrombus

Fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) are commonly encountered on MR imaging studies performed shortly after the onset of acute ischemic stroke. Prior reports have speculated regarding the pathogenesis of this finding, yet definitive correlative angiographic studies have not been performed. We studied the pathophysiologic and hemodynamic correlates of FVH on conventional angiography and concurrent MR imaging sequences. Retrospective review of FLAIR and gradient-refocused echo MR imaging sequences acquired immediately before conventional angiography for acute stroke was conducted in a blinded fashion. The presence, location, and morphology of FVH were noted and correlated with markers of thrombotic occlusion and collateral flow on angiography. Angiographic collaterals were graded on a 5-point scale incorporating extent and hemodynamic aspects. A prospective ischemic stroke registry of 632 patients was searched to identify 74 patients (mean age, 63.4 +/- 20 years; 48% women) having undergone FLAIR sequences immediately before angiography. Median time from FLAIR to angiography was 2.9 hours (interquartile range, 1.1-4.7 hours). FVH were present in 53/74 (72%) of all acute stroke cases with subsequent angiography. FVH distal to an arterial occlusion were associated with a high grade of leptomeningeal collateral blood flow. FVH are observed in areas of blood flow proximal and distal to stenosis or occlusion and are noted with more extensive collateral circulation.

Collateral Function in Patients with Coronary Occlusion Evaluated by 201Thallium Scintigraphy

The present study evaluated the impact of the angiographically documented collaterals on regional myocardial perfusion measured by 201thallium scintigraphy in patients with a chronic total occlusion. The study included 60 patients with chronic total occlusion who underwent rest-stress myocardial perfusion scintigraphy and coronary angiography. All patients had angiographic evidence of coronary collaterals. Patients were divided into two groups: group one had well-developed coronary collateral vessels (n=35) and group II had poor coronary collateral development (n=25). Patients with chronic total occlusion had severe and extensive stress-induced myocardial perfusion defects regardless of the grade of angiographic coronary collaterals. The perfusion defects in the group with good collaterals were predominantly reversible, suggesting that coronary collaterals preserved myocardial viability in the regions subtended by a total coronary occlusion. A significant correlation between good collaterals with complete protection and poor collaterals with no protection was noted. Our results demonstrate a protective effect of collaterals on myocardial perfusion during coronary occlusion. The effective angiographic collaterals may prevent resting regional wall motion abnormalities but do not appear to protect against stress-induced perfusion defect.

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

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. 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. 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. 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.

Good Collaterals Predict Viable Myocardium

The authors undertook this study to see whether highly developed coronary collaterals at an area shed by a totally occluded coronary artery predicts myocardial viability. Percutaneous coronary intervention (PCI) of a totally occluded coronary artery has been debated since its introduction. It is recommended to search for viable myocardium before opening a totally occluded coronary artery; however, there is no practical yet sensitive method of assessing myocardial viability in the catheterization laboratory. Forty-seven consecutive patients (12 women, 25.5%; 35 men, 74.5%), each with 1 totally occluded coronary artery, were prospectively enrolled to the study. After the diagnostic coronary angiography, all patients underwent dobutamine stress echocardiography to determine viable myocardium at the territory of the totally occluded coronary artery, and the status of angiographic coronary collaterals was assessed. Patients were then divided into 2 groups according to the presence (Group A) or absence (Group B) of viable myocardium by stress echocardiography. Eighteen patients (38.3%) had viable myocardium (Group A) in the area shed by the totally occluded coronary artery and 29 patients (61.7%) had nonviable myocardium (Group B). The incidences of significant coronary collateral circulation to the viable (Group A) and nonviable (Group B) areas were 66.7% (12 patients) and 20.7% (6 patients), respectively (p = 0.002). Logistic regression analysis was used to evaluate the independent factors for viable myocardium, and only significant coronary collateral circulation was found to be an independent factor for the detection of viable myocardium (p = 0.006, OR 16.7, 95% CI 2.25 to 124.4). The sensitivity and specificity of good collateral circulation for the detection of viable myocardium were 75% and 65.7%, respectively. The positive predictive and negative predictive values of the good coronary collateral circulation in detecting viable myocardium were 75% and 79%, respectively. The authors conclude that good coronary collaterals have a high sensitivity and positive predictive value for the prediction of viability as shown by dobutamine echocardiography, and only by assessing the coronary collateral circulation can one decide for percutaneous coronary revascularization, if not for coronary artery bypass surgery.

Transesophageal Doppler Echocardiographic Detection of Intramyocardial Collateral Flow to the Right Coronary Artery and Changes in the Flow to the Inferior Left Ventricular Wall Immediately After Coronary Artery Bypass Grafting

This study examined the feasibility of Doppler transesophageal echocardiography (TEE) to detect collateral flow to the myocardium supplied by the right coronary artery (RCA) in the inferior left ventricular wall. Forty-four patients who underwent elective coronary artery bypass grafting (CABG) were prospectively studied. Presence of collateral flow to the RCA was diagnosed on preoperative angiography using the Rentrop score and by intraoperative Doppler TEE. Agreement of the 2 methods was analyzed by calculating the kappa coefficient. Collateral flow was present on preoperative angiography in 19 patients and absent in 25 patients. Intraoperative TEE detected collateral flow in the inferior wall in 15 patients (79%) with and 3 patients (12%) without angiographic collaterals, resulting in a kappa coefficient for agreement of 0.67 (95% confidence interval 0.45 to 0.90). Baseline collateral flow disappeared after CABG in 12 of 14 patients with grafting of the RCA but persisted in all patients without such grafting. Physiologic flow in the inferior wall was detected by TEE in a total of 27 patients at baseline and in 38 patients after CABG (p = 0.0018); its peak velocity increased after surgery only in the subgroup of patients with grafting of the RCA. In conclusion, these findings indicate that Doppler TEE may detect collateral flow in the inferior left ventricular wall, and that there are typical changes in collateral and physiologic flow after CABG.

Role of angiographic coronary artery collaterals in transient ischemic left ventricular cavity dilatation during stress echocardiography

The role of coronary artery collaterals in transient ischemic left ventricular (LV) dilatation (TID) during stress echocardiography is not well defined. Transient ischemic LV dilatation is a marker for extensive and severe coronary artery disease and represents patients without good collaterals. We evaluated 212 consecutive patients (57 +/- 16 years, 70% male) who had coronary angiography and stress echocardiography within a 3-month period. This cohort of patients was divided into three groups based on type of collaterals: Group A: no collaterals; Group B: collaterals supplied by vessels without flow-limiting stenosis (good collaterals); Group C: collaterals supplied by vessels with flow-limiting stenosis (bad/jeopardized collaterals). In all patients, angiographic jeopardy score (AJS), ejection fraction (EF), and wall motion score index (WMSI) at rest and during stress were evaluated. Transient ischemic LV dilatation was defined as transient increase in the end-systolic dimensions from rest to peak stress. Transient ischemic LV dilatation was present in 42 (20%) patients. Patients with TID had a lower EF, higher AJS, greater number of ischemic segments, and higher peak WMSI. Patients with TID in Group A (no collaterals) and Group C (jeopardized collaterals) had a greater percentage of multivessel disease than those in Group B (good collaterals). Presence of Group A or Group C collaterals was a predictor of TID even after controlling for multivessel disease, rest and peak WMSI, and left anterior descending artery disease. Transient ischemic LV dilatation on stress echocardiography is a marker for extensive and severe coronary artery disease and represents patients with angiographically absent collaterals or those with jeopardized coronary collaterals.

Patterns of portal vein occlusion and their aetiological significance.

Clinical and angiographic findings in 53 patients with portal vein occlusion were reviewed to determine the relationship between the pattern of venous occlusion and its aetiology. Five major patterns were identified. Group 1 comprised three children with idiopathic intrahepatic portal vein occlusion alone (hepatoportal sclerosis). Those in group 2 (25 patients), with occlusion of the main portal vein, accounted for almost half the total number and for most of those with a probable congenital aetiology. The ten patients in group 3 had angiographic occlusion and collateralization of the main portal and superior mesenteric veins. Intra-abdominal sepsis, other than that from pancreatic disease, was associated with this pattern of venous occlusion in which the splenic vein is spared. No patients with isolated portal and splenic vein occlusion (group 4) were recorded. Widespread thrombosis throughout the portal venous system (group 5; 15 patients) had a multifactorial aetiology but was typically observed in hypercoagulable states that were also associated with hepatic vein occlusion or other deep vein thromboses.

Impact of Coronary Collaterals on Outcome Following Percutaneous Coronary Intervention (from the National Heart, Lung, and Blood Institute Dynamic Registry)

Coronary collateral circulation is beneficial in patients with coronary artery disease, but controversy still exists regarding the association between angiographic collaterals and outcome after percutaneous coronary intervention (PCI). We compared the baseline characteristics and cumulative 1-year event rates of consecutive patients undergoing PCI by target vessel collateral status-no angiographic evidence of collateral circulation (NC; n = 5051), treated artery supplied collaterals (SC; n = 239), and treated artery received collaterals (RC; n = 893)-using the National Heart, Lung, and Blood Institute Dynamic Registry. Patients in the SC group were older and had more previous coronary bypass surgery, myocardial infarction, co-morbid illness, and heart failure than the NC and RC groups and had less often undergone revascularization for acute myocardial infarction (p <0.01 for all). The total angiographic PCI success was comparable for the SC and NC groups but higher than for the RC group (94.1% vs 94.4% vs 83.9%, respectively; p <0.001). Overall stent use was 77.5% and was highest in the SC group (82.4%, p <0.001). At 1 year, significant differences in outcome were observed by collateral status. Compared with the NC group, patients with PCI of a SC artery had higher adjusted mortality (relative risk [RR] 1.95, 95% confidence interval [CI] 1.27 to 3.01, p = 0.002) and death/myocardial infarction (RR 1.75, 95% CI 1.26 to 2.45, p <0.001) rates. Patients with PCI of a RC vessel, conversely, had lower adjusted death/myocardial infarction (RR 0.72, 95% CI 0.54 to 0.96, p = 0.02) and repeat revascularization (RR 0.73, 95% CI 0.59 to 0.91, p = 0.005) rates. In conclusion, our results suggest that PCI on collateralized vessels is warranted, but that patients with PCI in arteries that supply collaterals are a high-risk group that may benefit from closer follow-up and complete revascularization.

Plasma Matrix Metalloproteinase-9, Tissue Inhibitor of Metalloproteinase-2, and CD40 Ligand Levels in Patients With Stable Coronary Artery Disease

Endogenous matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitor of metalloproteinases (TIMPs), are important mediators of extracellular matrix remodeling, which is integral to plaque progression in coronary artery disease. In addition, high levels of the soluble fragment of CD40 ligand (sCD40L) have previously been associated with adverse cardiovascular outcomes. We hypothesized that circulating levels of MMP-9, TIMP-1, TIMP-2, and sCD40L were abnormal in patients who had stable coronary artery disease, and these levels were compared with those in matched controls. We also hypothesized correlations of MMPs, TIMPs, and sCD40L to each other and to high-sensitivity C-reactive protein (a proinflammatory marker), white blood cell count, severity of coronary artery disease (based on angiographic measurements of atherosclerotic burden), and coronary collateralization. We studied 204 adult patients who attended our unit for outpatient diagnostic cardiac catheterization for the investigation of suspected coronary artery disease. Coronary angiograms were scored for atheroma burden and stenosis by 2 independent observers. Circulating levels of MMP-9, TIMP-1, TIMP-2, and sCD40L were measured by enzyme-linked immunosorbent assay. Plasma levels of MMP-9 (p = 0.0099), TIMP-2 (p = 0.0019), and sCD40L (p <0.001), but not TIMP-1 (p = 0.463) were high in patients compared with healthy controls. In patients who had coronary artery disease, MMP-9 and high-sensitivity C-reactive protein levels were significantly higher in women than in men. Only MMP-9 correlated modestly with total white blood cell count (Spearman's correlation, r = 0.274, p = 0.002). Logistic regression of cardiovascular risk factors showed that only white blood cell count was independently associated with MMP-9 (p = 0.02). After standardizing for atheroma and stenosis scores, there were no statistically significant differences in our research indexes in patients who had angiographic collaterals compared with those who did not. In conclusion, stable coronary artery disease is associated with abnormal circulating levels of MMP-9, TIMP-2, and sCD40L, which do not appear to related to each other or to severity of coronary artery disease or collateralization. The gender difference in high-sensitivity C-reactive protein and MMP-9 levels may provide insight into the pathophysiology of coronary artery disease in men and women, and further studies are warranted to explore this potential link.