Coronary Artery Chronic Total Occlusion Research Articles

Activation of Hypoxia-Inducible Factor by Di-Methyl Oxalyl Glycine (DMOG) Increases Neovascularization within Ischaemic Myocardium in a Porcine Coronary Artery Occlusion Model

Introduction: Chronic total coronary artery occlusion (CTO) in man remains a significant challenge for percutaneous coronary intervention (PCI) and a common reason for coronary artery bypass surgery, as often the CTO cannot be crossed. This study investigated whether a potential angiogenic treatment, the prolyl-4-hydroxylase inhibitor, di-methyl oxalyl glycine (DMOG), would increase collateral vessel formation and myocardial perfusion without opening the CTO in a porcine model of coronary CTO. Methods: We assessed the effect of DMOG upon tube formation of HUVEC in a matrigel assay in vitro. DMOG was loaded onto a polymer-coated coronary stent. Copper-coated stents were used to produce a coronary CTO in 20 pigs. DMOG-loaded or control stents were implanted in an alternating, blinded manner at day 28, proximal to the CTO. Angiographic and physiological flow data were collected at day 56, when the animals were sacrificed and the collateral vessels counted. Results: DMOG increased tubule formation in vitro by 77% compared with control (p<0.0001). DMOG was successfully loaded onto the polymer coated stent, as evidenced by the same assay. A CTO was present at angiography in all animals 28 days. At 56 days there was a trend towards a greater increase in angiographic collateral vessel area around the CTO in the DMOG group compared with controls +84.5% vs. +16.5%, respectively, p=0.057). Histology revealed a significant increase in the number of collateral vessels around the site of occlusion in the DMOG group vs control (29.9?2.6 vs 18.4?3.1, respectively; p=0.01). There was no difference between the groups in terms of collateral flow index at day 56. Conclusion: DMOG, delivered on a polymer-coated stent, proximal to an occluded porcine coronary artery, increased the number of collateral vessels seen at the site of vessel occlusion but not to a level sufficient to increase measures of functional flow.

Use of the venture wire control catheter for the treatment of coronary artery chronic total occlusions

The Venture catheter (St Jude, Minneapolis, MN) has a deflectable tip for facilitating wire steering and a stiff body. Both properties can be useful in percutaneous coronary interventions (PCI) of coronary chronic total occlusions (CTOs). We reviewed 26 consecutive patients in whom the Venture catheter was utilized during coronary CTO PCI at our institution between May 2008 and September 2009. Mean age was 63 ± 9 years and 96% of the patients were men. The CTO target lesion was located in the right coronary artery (35%), left anterior descending artery (27%), circumflex (27%) or a saphenous vein graft (4%). A prior attempt for CTO PCI had been done in 19%. The primary CTO PCI approach was antegrade in 92% and retrograde in 8%, but a retrograde approach was used in an additional 27% of the patients after antegrade approach failed. The Venture catheter was used to overcome vessel tortuosity (73%), for CTOs with side branch at the occlusion site (15%), to facilitate collateral branch wiring during retrograde PCI (8%), and to provide extra support (4%). The overall CTO PCI success rate was 77% and was 92% in patients with upfront Venture catheter use and in 64% of patients in whom the Venture was used after PCI attempts using other equipment failed. Procedural failure was due to inability to cross the lesion in all cases. The Venture catheter can facilitate CTO PCI, especially in patients with marked coronary tortuosity or when additional support is required.

Blocking Interferon β Stimulates Vascular Smooth Muscle Cell Proliferation and Arteriogenesis

Increased interferon (IFN)-β signaling in patients with insufficient coronary collateralization and an inhibitory effect of IFNβ on collateral artery growth in mice have been reported. The mechanisms of IFNβ-induced inhibition of arteriogenesis are unknown. In stimulated monocytes from patients with chronic total coronary artery occlusion and decreased arteriogenic response, whole genome expression analysis showed increased expression of IFNβ-regulated genes. Immunohistochemically, the IFNβ receptor was localized in the vascular media of murine collateral arteries. Treatment of vascular smooth muscle cells (VSMC) with IFNβ resulted in an attenuated proliferation, cell-cycle arrest, and increased expression of cyclin-dependent kinase inhibitor-1A (p21). The growth inhibitory effect of IFNβ was attenuated by inhibition of p21 by RNA interference. IFNβ-treated THP1 monocytes showed enhanced apoptosis. Subsequently, we tested if collateral artery growth can be stimulated by inhibition of IFNβ-signaling. RNA interference of the IFNβ receptor-1 (IFNAR1) increased VSMC proliferation, cell cycle progression, and reduced p21 gene expression. IFNβ signaling and FAS and TRAIL expression were attenuated in monocytes from IFNAR1(-/-) mice, indicating reduced monocyte apoptosis. Hindlimb perfusion restoration 1 week after femoral artery ligation was improved in IFNAR1(-/-) mice compared with wild-type mice as assessed by infusion of fluorescent microspheres. These results demonstrate that IFNβ inhibits collateral artery growth and VSMC proliferation through p21-dependent cell cycle arrest and induction of monocyte apoptosis. Inhibition of IFNβ stimulates VSMC proliferation and collateral artery growth.

E0480 Longterm clinical outcome of patients undergoing successful percutaneous coronary intervention for chronic total coronary artery occlusion

IntroductionThere are limited data on the impact of successful chronic total occlusion (CTO) revascularisation by percutaneous coronary intervention (PCI) on long-term outcomes.MethodsBetween June 1993 and December 2006, a total of...

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

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. A total of 83 patients with mild to moderate loss of renal function (30mL/min/1.73m(2)≤eGFR<90mL/min/1.73m(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). 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.

TCT-27: Improved Cardiac Survival and Quality of Life after Successful Percutaneous Recanalisation of Coronary Artery Chronic Total Occlusions: a Single-Centre Experience

TCT-27: Improved Cardiac Survival and Quality of Life after Successful Percutaneous Recanalisation of Coronary Artery Chronic Total Occlusions: a Single-Centre Experience

Computed tomography angiography-guided percutaneous coronary intervention in chronic total occlusion

The aim of this study is to investigate if dual-source computed tomography (DSCT) could guide the percutaneous coronary intervention (PCI) of chronic total occlusion (CTO). We enrolled patients who were confirmed to have at least one native coronary artery CTO by DSCT before they underwent selective PCI in the period from December 2007 to October 2008. A CTO was defined as an obstruction of a native coronary artery with no luminal continuity. The CT-guided PCI procedure involved placing CT and fluoroscopic images side-by-side on the screen. DSCT images were analyzed for location, segment, plaque characteristics, calcification, and proximal lumen diameter of the CTO before PCI. The guidewire was advanced and manipulated under CT guidance. The PCI was carried out and the results were compared. Seventy-four CTOs were assessed. PCI was successful in 57 cases of CTOs (77.0%). According to the results, CTOs were divided into two groups: successful-PCI and failed-PCI. All coronary artery paths of CTOs were clearly recognized by DSCT. In the successful-PCI group, soft plaques were detected much more often than those in the failed-PCI group, but fibrous and calcified plaques were seen more often in the failed-PCI group. Calcification severity in CTO segments showed a significant difference between the groups (P=0.014). Calcified plaques were detected in 20 (35.1%) lesions in the successful-PCI group. More than 70% of the failures were calcified plaques, of which there were two arc-calcified and one circular-calcified lesions. Occlusions were longer in the failed-PCI group than those in the successful-PCI group [(38.8+/-25.0) vs. (18.0+/-15.3) mm, respectively, P<0.01]. Fewer guidewires were used in the successful-PCI group compared with the failed-PCI group (1.7+/-1.0 vs. 2.5+/-0.9, respectively, P<0.01). The logistic regression analysis indicated that predictors of recanalization of CTOs included occlusion length (P=0.0035, risk ratio (RR)=0.93) and calcification severity (P=0.05, RR=0.27). Multi-linear trends analysis showed that the factors affecting procedural time were CTO location (P=0.0141) and occlusion length (P=0.0035). DSCT could delineate the path of CTOs and characterize plaques. The outcomes of PCI were related to thrombolysis in myocardial infarction (TIMI) flow grade, CTO characteristics, severity of calcified plaques, and the length of occlusive segments. Occlusion length and calcification severity were independent predictors of CTOs. Occlusion length and CTO segments could also help to estimate the duration of interventional procedures.

104 Upregulation of hypoxia-inducible factor 1α by di-methyl oxalyl glycine promotes angiogenesis within ischaemic myocardium in a porcine coronary occlusion model

Introduction Chronic total coronary artery occlusion (CTO) remains a significant challenge for percutaneous coronary intervention (PCI), a frequent cause of angina pectoris and a common reason for referral for coronary bypass surgery. The purpose of this study was to investigate a potential alternative treatment strategy for promotion of angiogenesis and collateral blood flow. To this end we investigated the effect of the prolyl-4-hydroxylase inhibitor di-methyl oxalyl glycine (DMOG) on collateral vessel formation in an entirely endovascular porcine model of coronary occlusion. Method DMOG was loaded onto a polymer-coated coronary stent. A percutaneous model employing copper-coated stents was used to produce CTO in 20 Yorkshire white pigs. Coronary occlusions were present in all animals at 28 days. DMOG stents were implanted at day 28 and angiographic and physiological data collected on distal coronary and collateral flow. At day 56 the animals were sacrificed and histological analysis performed. Results A complete total coronary occlusion was present in all animals at day 28 following implantation of a copper stent. (Abstract 104 Figure 1) At 56 days there was a trend to a greater increase in angiographic collateral volume in the DMOG group (10±4.1 mm2 increase vs 3.6±1.5 mm 2 ; 84.5% increase vs 16.5%, p=0.057). There was no difference in collateral flow index between the groups at day 56. Histology revealed an increase in total number of collateral vessels seen around the site of occlusion in the DMOG group (29.9±2.6 vs 18.4±3.1, p=0.01) with similar distal collateral vessel density. (Abstract 104 Figure 2) Conclusions Implantation of a copper stent provides a reliable endovascular method of producing a CTO. DMOG increases the number of collateral vessels seen at the site of vessel occlusion in this endovascular model of CTO but did not increase neovascularisation in distal tissue. At baseline distal myocardium was subtended by extensive antegrade collaterals. The effect of DMOG in increasing neovascularisation appeared to be restricted to ischaemic tissue.

Right coronary artery chronic total occlusion revascularization by knuckle technique through right gastroepiploic artery graft

Sirs:Angina pectoris following bypass surgery is caused bygraft failure or new lesions developing in the native coro-nary artery. Right gastroepiploic artery (RGEA) has beenshown to have a good short- and long-term patency whenanastomosed to the right coronary artery (RCA). Long-term patency is 80–90% at 5 years; however, it decreasesto approximately 62% at 10 years [1].Many reports suggest that successful revascularizationof chronic total occlusion (CTO) subtending viable myo-cardium determines a more favorable long-term outcomewith survival enhancement and improvement in quality oflife [2, 3].We present a case of RCA CTO recanalization usingretrograde approach through RGEA graft.Case reportA 64-year-old man ex smoker with hypercholesterolemia,type II diabetes mellitus, mild hypertension underwentcoronary artery bypass graft (CABG) surgery for anteriormyocardial infarction in 1997 with left internal mammaryartery (LIMA) on left anterior descending (LAD) andRGEA on posterior descending artery (PDA). Since 2003the patient referred onset of angina at medium workload;he performed an exercising test which was interrupted at75 W for V3–V6 down-sloping ST depression and non-sustained ventricular tachycardia. For this reason thepatient was referred for a new coronary angiography(CAG) which showed: LIMA patent, distal LAD withsevere stenosis, RCA proximal occlusion, RGEA patentwith disease at the anastomosis and in native distal RCA(crux) (Fig. 1a–b). The patient was referred for a newCABG in 2004; however, he refused this treatment and hestarted optimal medical therapy. After 5 years, due tosymptoms worsening, the patient underwent CAG (May2009) which showed a comparable angiographic pattern tothe previous one. Thus, the patient underwent a stressmyocardial scintigraphy which showed severe reversibleinfero-lateral hypoperfusion with a normal left ventricularfunction. Thereafter it was decided to attempt RCA per-cutaneous revascularization in June 2009.Unfractionated heparin (5,000 units intravenously) wasadministered. A 7 French Amplatz left and a 7 FrenchJudking right guiding catheter were used to engage RCAostium and RGEA graft, respectively. Contrast meaninjection from RGEA confirmed severe disease at theanastomosis and distally native RCA. The lesion was firstapproached by antegrade with a soft-tapered polymericguidewire (Fielder XT, Asahi) and a microcatheter (Fine-cross, Terumo) which was advanced up to the mid-RCA.As this guidewire was not able to progress any further, itwas exchanged using the microcatheter with an interme-diate-stiffness one (Medium guidewire, Asahi). The Med-ium guidewire was able to advance up to the mid-distal partof the vessel where it stopped due to severe calcifications.Thus, a soft-tapered polymeric guidewire (Fielder XT,Asahi) was inserted with a Corsair microcatheter (Asahi)through RGEA by retrograde. This wire got through thesevere disease at the anastomosis; however, it stuck in the

Right coronary artery chronic total occlusion in presence of anomalous origin of left coronary artery

Right sinus origin of left coronary artery is a very uncommon congenital coronary anomaly. The presence of an associated totally occluded right coronary artery represents an exceedingly rare picture. An accurate morphologic identification of anomalous arteries, by multi-detector computed tomography, is mandatory before planning any therapeutic intervention. We report an interesting case of chronic total occlusion of the right coronary artery in a young patient with anomalous left coronary artery.

Retrograde Angioplasty: An Option for Total Coronary Artery Occlusions

The safety and effectiveness of angioplasty for chronic total occlusions of the coronary arteries have been demonstrated in several studies, but the success rate is less than for conventional interventions. The complexity of the procedures presents a major challenge. In selected cases, performing angioplasty of the occlusion via a retrograde approach has been used as an alternative. We present the first published Spanish series, comprising 11 procedures in 9 patients, in which a retrograde approach was used to eliminate obstructions caused by chronic total coronary artery occlusions. The characteristics, outcomes and complications of the procedure were assessed.

PERCUTANEOUS INTERVENTION OF ACUTELY OCCLUDED SAPHENOUS VEIN GRAFTS: CONTEMPORARY TECHNIQUES AND OUTCOMES

OBJECTIVES To examine the contemporary acute and long-term outcomes after percutaneous coronary interventions (PCI) of acutely occluded saphenous vein grafts (SVGs). BACKGROUND PCI of acutely thrombosed SVGs carries low success rates. It is unknown whether outcomes have improved with contemporary PCI techniques. METHODS We reviewed the acute and long-term outcomes of 34 consecutive patients who underwent PCI of 36 acutely occluded SVGs at our institution between 2003 and 2009. RESULTS Mean patient age was 70 +/- 10 years and 39% had stent thrombosis. Mean SVG age was 14 +/- 6 years. SVG PCI was successful in 81%. In 3 patients, PCI of the target vessel native chronic total occlusion (CTO) was attempted after SVG PCI failed and was successful in 2, increasing the overall target myocardial territory revascularization success rate to 86%. Adjunctive PCI techniques were used as follows: mechanical thrombectomy (69%), rheolytic thrombectomy (39%), embolic protection devices (25%) and laser (14%). Stents (61% drug-eluting) were implanted in 78% of the treated lesions. Mean follow up was 2.3 +/- 1.9 years. At 1 and 3 years, mortality was 8% and 42%, an acute coronary syndrome occurred in 15% and 41% and repeat coronary revascularization was required in 28% and 38%, respectively. CONCLUSIONS In this particular population of thrombosed SVG PCIs, a high incidence of stent thrombosis was observed and procedural success rate was 81% with an additional 5% undergoing successful native coronary artery CTO PCI. Patients presenting with thrombosed SVGs were at high risk for recurrent events.

Current considerations regarding the percutaneous revascularization of chronic total coronary occlusions

Chronic total coronary artery occlusions are commonly encountered, occurring in 15–33% of patients in the angiography suite. Reasons to consider percutaneous coronary revascularization of these lesions include the relief of angina, enhancement of left ventricular ejection fraction and the potential for improved survival. Owing to the complex nature of these lesions, attempts at percutaneous revascularization have traditionally been infrequent (≤12%of encountered cases). Advances in technique and equipment have resulted in improved success rates that now approach 90% at specialized centers. It remains to be seen if these positive results can be achieved by the interventional cardiology community at large.

Successful treatment of a proximal right coronary artery chronic total occlusion using 5F IKARI guide catheter via transradial approach

Successful treatment of a proximal right coronary artery chronic total occlusion using 5F IKARI guide catheter via transradial approach

Intravascular Ultrasound Comparison of the Retrograde Versus Antegrade Approach to Percutaneous Intervention for Chronic Total Coronary Occlusions

We sought to evaluate the results of the antegrade versus retrograde chronic total occlusion (CTO) technique with intravascular ultrasound (IVUS) imaging. The most common failure mode of CTO interventions remains the inability to successfully cross the occlusion with a guidewire. Recently, the retrograde approach through collateral channels has been introduced to cross complex CTOs. Between October 2002 and April 2008, IVUS was performed in 48 de novo CTO lesions after guidewire crossing +/- pre-dilation with a 1.5- to 2.0-mm balloon. Twenty-three lesions were treated via the antegrade approach (Ante), and 25 lesions were treated via the retrograde approach (Retro). Right coronary artery (RCA) CTOs were treated more frequently via the Retro technique. Although the CTO length was much longer in the Retro group (45 +/- 26 mm vs. 18 +/- 9 mm, p < 0.0001), at the end of the procedure Thrombolysis In Myocardial Infarction flow grade 3 was obtained in all patients. There were no significant differences between the 2 groups in minimum stent area and stent expansion. However, the incidence of the composite end point-subintimal wiring, angiographic extravasation, coronary hematoma, or IVUS-detected coronary perforation-was higher in the Retro group (68% vs. 30%, p = 0.01); and the guidewire was more often subintimal in the Retro group (40% vs. 9%, p = 0.02). The retrograde approach is a promising option for complex CTO segments, especially long RCA CTOs. Intravascular ultrasound can be a useful tool for the detection of procedure-related vessel damage and subintimal wire tracking.

Retrograde recanalization of native coronary artery chronic occlusions via acutely occluded vein grafts

Treatment of acutely occluded saphenous vein grafts may be challenging due to large thrombus burden and diffuse disease. We report two cases of thrombotic saphenous vein graft occlusion, in which after percutaneous attempts to recanalize the saphenous vein graft failed, the target native coronary artery chronic total occlusions were successfully treated using a retrograde approach.

Retrograde recanalization of chronic total coronary artery occlusion using a novel “reverse wire trapping” technique

Percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) remains a technical challenge for the interventional cardiologists. Recently, modified techniques based on the retrograde approach have demonstrated that this approach could increase the success rate for PCI of CTO. In the current report, we describe a novel "reverse wire trapping" technique that can help create an antegrade wire route to open CTO after the wire has passed through the CTO retrogradely, even though the retrograde balloon dilatation or antegrade wiring was unapproachable.

Successful Transradial Antegrade Coronary Intervention of a Rare Right Coronary Artery High Anterior Downward Takeoff Anomalous Chronic Total Occlusion by Double-Anchoring Technique and Retrograde Guidance

Percutaneous coronary intervention (PCI) via a transradial approach has become feasible for the treatment of chronic total occlusion (CTO). However, abnormalities such as anomalous origin coronary arteries represent the most technically challenging cases for interventional cardiologists. In this case, we describe a CTO in a rare anomalous right coronary artery (RCA) that originated from a high anterior takeoff with downward direction; transradial recanalization was the second attempt at RCA CTO and was successfully performed by employing a double-anchoring technique with an antegrade and retrograde approach.

Subintimal tracking and re‐entry technique with contrast guidanc: A safer approach

To assess the procedural and clinical outcomes from a modified subintimal tracking and re-entry (STAR) procedure performed using contrast guidance. Previous data showed that recanalizing a chronic total occlusion (CTO) with the STAR technique was possible. However, this technique was considered difficult and therefore has only been adopted by a limited number of experienced operators. Patients (n = 68) with a CTO of a native coronary artery treated by a single operator with this technique were included. The right coronary artery was involved in 79.4%, the morphology was blunt in 77.9%, and CTO length was longer than 20 mm in 67.6%. Angiographic success rate was 80.9% with a 70.6% rate of complete recanalization. Stent implantation was performed in 82.3% of cases, with drug-eluting stents (DES) implanted in the majority (92.7%). Procedural complications occurred in 10.3% of cases. There were no episodes of myocardial infarction during follow-up, with 1 case (1.5%) of cardiac death. There were no cases of definite or probable stent thrombosis, and there was 1 (1.5%) possible stent thrombosis. The overall rate of in-segment binary restenosis was 44.7%, and target lesion revascularization (TLR) was performed in 25% of lesions. The rate of TLR in lesions treated with DES was 29.4% and in those treated with bare-metal stents was 50%. The contrast-guided STAR technique appears to be feasible and relatively safe. However, this procedure is limited by a high rate of restenosis even with DES, and a second procedure may be necessary to obtain a definitive result.

Treatment of chronic total occlusion by retrograde passage of stents through an epicardial collateral vessel

Chronic total occlusion (CTO) may occur in as many as 30-40% of patients with coronary artery disease. Retrograde revascularization through a collateral channel has been described earlier. We report the first case of retrograde passage of a stent through an epicardial collateral to revascularize a right coronary artery CTO.