Guiding catheter inner lumen damage during percutaneous coronary intervention.

Guiding catheter damage and body wire intermingling are uncommon complications of standard operational procedures. Optimal application of this device includes replacing the small guiding catheter upon excessive resistance during stent insertion.

Isolated ascending aorta dilatation is associated with increased risk of abdominal aortic aneurysm.

BACKGROUND: Abdominal aortic aneurysm (AAA) is an asymptomatic condition characterized by progressive dilatation of the aorta. The purpose of this study is to identify important 2D-TTE aortic indices associated with AAA as predictive tools for undiagnosed AAA. METHODS: In this retrospective study, we evaluated the size of the ascending aorta in patients without known valvular diseases or hemodynamic compromise as predictive tool for undiagnosed AAA. We studied the tubular ascending aorta of 170 patients by 2-dimensional transthoracic echocardiography (2D-TTE). Patients were further divided into two groups, 70 patients with AAA and 100 patients without AAA with normal imaging results. RESULTS: Dilatation of tubular ascending aorta was measured in patients with AAA compared to the group with absent AAA (37.5 ± 4.8 mm vs. 31.2 ± 3.6 mm, p < 0.001, respectively) and confirmed by computed tomographic (CT) (35.6 ± 5.1 mm vs. 30.8 ± 3.7 mm, p < 0.001, respectively). An increase in tubular ascending aorta size was associated with the presence of AAA by both 2D-TTE and CT (r = 0.40, p < 0.001 and r = 0.37, p < 0.001, respectively). The tubular ascending aorta (D diameter) size of ≥33 mm or ≥ 19 mm/m2 presented with 2-4 times more risk of AAA presence (OR 4.68, CI 2.18-10.25, p = 0.001 or OR 2.63, CI 1.21-5.62, p = 0.02, respectively). In addition, multiple logistic regression analysis identified tubular ascending aorta (OR 1.46, p < 0.001), age (OR 1.09, p = 0.013), gender (OR 0.12, p = 0.002), and LVESD (OR 1.24, p = 0.009) as independent risk factors of AAA presence. CONCLUSIONS: An increased tubular ascending aortic diameter, measured by 2D-TTE, is associated with the presence of AAA. Routine 2D-TTE screening for silent AAA by means of ascending aorta analysis, may appear useful especially in older patients with a dilated tubular ascending aorta (≥33 mm).

Impact in total ischemic time and ST-segment elevation myocardial infarction admissions during COVID-19.

BACKGROUND: Despite the COVID-19 pandemic, cardiovascular disease is still the main cause of death in developed countries. Of these deaths, acute coronary syndromes (ACS) account for a substantial percentage of deaths. Improvement in ACS outcomes, are achieved by reducing the time from symptom onset until reperfusion or total ischemic time (TIT). Nevertheless, due to the overwhelming reality at the beginning of the pandemic, acute coronary syndrome (ACS) care may have been compromised. OBJECTIVES: We evaluated delays in TIT based on the date and timing of admissions in patients with STEMI, by a timeline follow-up form, before and during the current COVID-19 pandemic. METHODS: Between July 2018 and June 2020, two hundred and twelve patients diagnosed with ST-segment elevation myocardial infarction (STEMI) were admitted to our medical center. Upon presentation, cases were assigned a timeline report sheet and each time interval, from onset of symptoms to the catheterization lab, was documented. The information was later evaluated to study potential excessive delays throughout ACS management. RESULTS: Our data evidenced that during the COVID-19 pandemic ACS admissions were reduced by 34.54%, in addition to several in-hospital delays in patient's ACS management including delays in door-to-ECG time (9.43 ± 18.21 vs. 18.41 ± 28.34, p = 0.029), ECG-to-balloon (58.25 ± 22.59 vs. 74.39 ± 50.30, p = 0.004) and door-to-balloon time (57.41 ± 27.52 vs. 69.31 ± 54.14, p = 0.04). CONCLUSIONS: During the pandemic a reduction in ACS admissions occurred in our hospital that accompanied with longer in-hospital TIT due to additional tests, triage, protocols to protect and prevent infection within hospital staff, and maintenance of adequate standards of care. However, door-to-balloon time was maintained under 90 min.

A calcified chronic total occlusion preclinical model.

OBJECTIVE: To create an experimental chronic total occlusion (CTO) model with calcification by dietary modification (cholesterol, calcium carbonate, vitamin D) and local injection of pro-calcification factors (dipotassium phosphate, calcium chloride, and bone morphogenetic protein-2 [BMP-2]). BACKGROUND: Percutaneous revascularization of CTOs frequently fails in heavily calcified occlusions. Development of novel approaches requires a reproducible preclinical model of calcified CTO. METHODS: CTOs were created in 18 femoral arteries of 9 New Zealand White rabbits using the thrombin injection model. Dietary interventions included a high cholesterol diet (0.5% or 0.25%), calcium carbonate (150 mg × 3-5 days/week), and vitamin D (50,000 U × 3-5 days/week). In selected animals, BMP-2 (1-4 µg), dipotassium phosphate, and calcium chloride were injected locally at the time of CTO creation. Animals were sacrificed at 2 weeks (n = 4 arteries), 6 weeks (n = 4 arteries), and 10-12 weeks (n = 14 arteries). RESULTS: CTOs showed evidence of chronic lipid feeding (foam cells) and chronic inflammation (intimal/medial fibrosis and microvessels, inflammatory cells, internal elastic lamina disruption). In calcium/vitamin D supplemented rabbits, mineralization (calcification and/or ossification) was evident as early as 2 weeks post CTO creation, and in 78% of the overall arteries. Mineralization changes were not present in the absence of calcium/vitamin D dietary supplements. Mineralization occurred in 85% of BMP-treated arteries and 60% of arteries without BMP. CONCLUSIONS: Complex mineralization occurs in preclinical CTO models with dietary supplementation of cholesterol with vitamin D and calcium.

Difference in left atrial appendage remodeling between diabetic and nondiabetic patients with atrial fibrillation.

BACKGROUND: Diabetes mellitus (DM) is a common and increasingly prevalent condition in patients with atrial fibrillation (AFib). The left atrium appendage (LAA), a small outpouch from the LA, is the most common location for thrombus formation in patients with AFib. HYPOTHESIS: In this study, we examined LAA remodeling differences between diabetic and nondiabetic patients with AFib. METHODS: This retrospective study analyzed data from 242 subjects subdivided into two subgroups of 122 with DM (diabetic group) and 120 without DM (nondiabetic group). The study group underwent real-time 3-dimensional transesophageal echocardiography (RT3DTEE) for AFib ablation, cardioversion, or LAA device closure. The LAA dimensions were measured using the "Yosefy rotational 3DTEE method." RESULTS: The RT3DTEE analysis revealed that diabetic patients display larger LAA diameters, D1-lengh (2.09 ± 0.50 vs 1.88 ± 0.54 cm, P = .003), D2-width (1.70 ± 0.48 vs 1.55 ± 0.55 cm, P = .024), D3-depth (2.21 ± 0.75 vs 1.99 ± 0.65 cm, P = .017), larger orifice areas (2.8 ± 1.35 and 2.3 ± 1.49 cm2 , P = .004), and diminished orifice flow velocity (37.3 ± 17.6 and 43.7 ± 19.5 cm/sec, P = .008). CONCLUSIONS: Adverse LAA remodeling in DM patients with AFib is characterized by significantly LAA orifice enlargement and reduced orifice flow velocity. Analysis of LAA geometry and hemodynamics may have clinical implications in thrombotic risk assessment and treatment of DM patients with AFib.

Low High-Density Lipoprotein Cholesterol Predisposes to Coronary Artery Ectasia.

Coronary Artery Ectasia (CAE) is a phenomenon characterized by locally or diffuse coronary artery dilation of one or more coronary arteries. In the present study, the prevalence of acquired coronary ectasia and coronary risk factors for CAE was analyzed in patients undergoing cardiac catheterization for suspected ischemic heart disease. We retrospectively analyzed 4000 patients undergoing coronary angiography for suspected coronary artery disease at our cardiac catheterization unit, and a total of 171 patients were selected. The study group was divided into three groups, 65 patients with CAE, 62 patients with significant obstructive coronary artery disease, and 44 patients with normal coronary angiograms as a control group. A negative correlation was observed between high-density lipoprotein cholesterol (HDL-C) and the presence of CAE (r = -0.274, p < 0.001). In addition, HDL-C (OR, 0.858; CI, 0.749-0.984; p = 0.029), low-density lipoprotein cholesterol (LDL-C)/HDL-C ratio (OR, 1.987; CI, 1.542-2.882; p = 0.034), and hemoglobin (OR, 2.060; CI, 1.114-3.809; p = 0.021) were identified as independent risk factors for the development of CAE. In fact, we observed that a one-unit increase in HDL-C corresponded to a 15% risk reduction in CAE development and that each unit increase in hemoglobin could potentially increase the CAE risk by 2-fold. Low HDL-C could significantly increase the risk of developing CAE in healthy individuals. Elevated hemoglobin could predispose to subsequent dilation and aneurysm of the coronary artery. This work suggests that disordered lipoprotein metabolism or altered hemoglobin values can predispose patients to aneurysmal coronary artery disease.

Reduction in operator radiation exposure during transradial coronary procedures using a simple lead rectangle.

OBJECTIVES: Transradial access for percutaneous coronary intervention (PCI) reduces procedural complications however, there are concerns regarding the potential for increased exposure to ionizing radiation to the primary operator. We evaluated the efficacy of a lead-attenuator in reducing radiation exposure during transradial PCI. METHODS AND RESULTS: This was a non-randomized, prospective, observational study in which 52 consecutive patients were assigned to either standard operator protection (n = 26) or the addition of the lead attenuator across their abdomen/pelvis (n = 26). In the attenuator group patients were relatively older with a higher prevalence of peripheral vascular disease (67.9 vs 58.7 p = 0.0292 and 12% vs 7.6% p < 0.001 respectively). Despite similar average fluoroscopy times (12.3 ± 9.8 min vs. 9.3 ± 5.4 min, p = 0.175) and average examination doses (111866 ± 80790 vs. 91,268 ± 47916 Gycm2, p = 0.2688), the total radiation exposure to the operator, at the thyroid level, was significantly lower when the lead-attenuator was utilized (20.2% p < 0.0001) as compared to the control group. Amongst the 26 patients assigned to the lead-attenuator, there was a significant reduction in measured radiation of 94.5% (p < 0.0001), above as compared to underneath the lead attenuator. CONCLUSIONS: Additional protection with the use of a lead rectangle-attenuator significantly lowered radiation exposure to the primary operator, which may confer long-term benefits in reducing radiation-induced injury. ADVANCES IN KNOWLEDGE: This is the first paper to show that a simple lead attenuator almost completely reduced the scattered radiation at very close proximity to the patient and should be considered as part of the standard equipment within catheterization laboratories.

Site localization of painful lesions during radiofrequency ablation of pulmonary veins using circular multi-electrode catheters.

PURPOSE: Previous data showed that pain sensation was common during pulmonary vein isolation (PVI) using an 8-mm radiofrequency (RF) ablation catheter. Pain was more common in the left pulmonary veins (PVs). We characterized the location of pain during PVI using circular multi-electrode ablation catheters. METHODS: Included are all consecutive patients with atrial fibrillation (AF) who underwent PVI using the phased RF PVAC® catheter (Medtronic) or the irrigated nMARQ™ catheter (Biosense Webster) under conscious sedation between July 2011 and March 2015. Site of pain reaction was marked for each patient. RESULTS: A total of 251 patients (141 PVAC®, 110 nMARQ™) were studied; 214 (85 %) had at least one lesion associated with pain. Gender (r = 0.084, p = 0.186), type of AF (r = 0.048, p = 0.452), age (r = 0.078, p = 0.216), and repeat procedure (r = 0.018, p = 0.78) were not correlated with pain. There was no association between site of pain and catheter type; only 33% of the painful PVs were also the largest ones (p = 0.5, kappa = 0.03, R = -0.083). One-year freedom from AF was similar for patients with and without painful PVs (p = 0.6). The distribution of pain was as follows: 126 (59%) left superior PV (LSPV), 28 (13%) left inferior, 28 (13%) all PVs, 12 (5.6%) right superior, 12 (5.6%) right inferior, 18 (8.4%) left common, and 2 (0.9%) right common PV. CONCLUSIONS: PVI using multi-electrode catheters more commonly caused pain sensation in LSPV. There was no influence of catheter type or PV size on pain localization. Our findings, which are similar to those using an 8-mm ablation catheter, imply that location of pain is not catheter dependent but rather a reflection of autonomic physiology.

Distal coronary embolization following acute myocardial infarction increases early infarct size and late left ventricular wall thinning in a porcine model.

BACKGROUND: Distal coronary embolization (DCE) of thrombotic material occurs frequently during percutaneous interventions for acute myocardial infarction and can alter coronary flow grades. The significance of DCE on infarct size and myocardial function remains unsettled. The aims of this study were to evaluate the effects of DCE sufficient to cause no-reflow on infarct size, cardiac function and ventricular remodeling in a porcine acute myocardial infarction model. METHODS AND RESULTS: Female Yorkshire pigs underwent 60 min balloon occlusion of the left anterior descending coronary artery followed by reperfusion and injection of either microthrombi (prepared from autologous porcine blood) sufficient to cause no-reflow (DCE), or saline (control). Animals were sacrificed at 3 h (n = 5), 3 days (n = 20) or 6 weeks (n = 20) post-AMI. Cardiovascular magnetic resonance (CMR), serum troponin-I, and cardiac gelatinase (MMP) and survival kinase (Akt) activities were assessed. At 3d, DCE increased infarct size (CMR: 18.8% vs. 14.5%, p = 0.04; serum troponin-I: 13.3 vs. 6.9 ng/uL, p < 0.05) and MMP-2 activity levels (0.81 vs. 0.49, p = 0.002), with reduced activation of Akt (0.06 versus 0.26, p = 0.02). At 6 weeks, there were no differences in infarct size, ventricular volume or ejection fraction between the two groups, although infarct transmurality (70% vs. 57%, p< 0.04) and ventricular thinning (percent change in mid anteroseptal wall thickness:-25.6% vs. 0.7%, p = 0.03) were significantly increased in the DCE group. CONCLUSIONS: DCE increased early infarct size, but without affecting later infarct size, cardiac function or ventricular volumes. The significance of the later remodelling changes (ventricular thinning and transmurality) following DCE, possibly due to changes in MMP-2 activity and Akt activation, merits further study.

Perlecan heparan sulfate proteoglycan is a critical determinant of angiogenesis in response to mouse hind-limb ischemia.

BACKGROUND: Perlecan is a heparan sulfate proteoglycan (HSPG) constituent of the extracellular matrix with roles in cell growth, differentiation, and angiogenesis. The role of the HS side chains in regulating in vivo angiogenesis after hind-limb ischemia is unknown. METHODS: Heparan sulfate (HS)-deficient perlecan (Hspg2(Δ3/Δ3)) mice (n = 35), containing normal perlecan core protein but deficient in HS side chains, and wild-type (n = 33) littermates underwent surgical induction of hind-limb ischemia. Laser Doppler perfusion imaging (LDPI) and contrast-enhanced ultrasonography (CEU) provided serial assessment of hind-limb perfusion. Harvested muscles underwent immunostaining for endothelial cell density (CD31), real-time reverse transcription polymerase chain reaction RT-PCR for vascular endothelial growth factor (VEGF) mRNA expression and western blot analysis for VEGF and fibroblast growth factor (FGF)2 protein expression at days 2 and 28. RESULTS: Serial LDPI showed significantly greater perfusion recovery in ischemic limbs of wild-type compared with Hspg2(Δ3/Δ3) mice. CEU showed that normalized microvascular perfusion was increased in wild-type compared with Hspg2(Δ3/Δ3) mice at day 28 (0.67 ± 0.12 vs 0.26 ± 0.08; P = 0.001). CD31-positive cell counts were significantly higher in wild-type compared with Hspg2(Δ3/Δ3) mice on day 28 (122 ± 30 cells vs 84 ± 34 cells per high-power field [HPF]; P < 0.05). Endogenous VEGF mRNA expression (P < 0.05) and VEGF protein expression (P < 0.002) were significantly decreased in the ischemic limbs of Hspg2(Δ3/Δ3) mice compared with wild-type mice at day 2 and day 28, respectively. FGF2 protein expression showed no significant differences. CONCLUSIONS: These results suggest that the HS side chains in perlecan are important mediators of the angiogenic response to ischemia through a mechanism that involves upregulation of VEGF expression.

Heparan sulfate side chains have a critical role in the inhibitory effects of perlecan on vascular smooth muscle cell response to arterial injury.

Perlecan is a proteoglycan composed of a 470-kDa core protein linked to three heparan sulfate (HS) glycosaminoglycan chains. The intact proteoglycan inhibits the smooth muscle cell (SMC) response to vascular injury. Hspg2(Δ3/Δ3) (MΔ3/Δ3) mice produce a mutant perlecan lacking the HS side chains. The objective of this study was to determine differences between these two types of perlecan in modifying SMC activities to the arterial injury response, in order to define the specific role of the HS side chains. In vitro proliferative and migratory activities were compared in SMC isolated from MΔ3/Δ3 and wild-type mice. Proliferation of MΔ3/Δ3 SMC was 1.5× greater than in wild type (P < 0.001), increased by addition of growth factors, and showed a 42% greater migratory response than wild-type cells to PDGF-BB (P < 0.001). In MΔ3/Δ3 SMC adhesion to fibronectin, and collagen types I and IV was significantly greater than wild type. Addition of DRL-12582, an inducer of perlecan expression, decreased proliferation and migratory response to PDGF-BB stimulation in wild-type SMC compared with MΔ3/Δ3. In an in vivo carotid artery wire injury model, the medial thickness, medial area/lumen ratio, and macrophage infiltration were significantly increased in the MΔ3/Δ3 mice, indicating a prominent role of the HS side chain in limiting vascular injury response. Mutant perlecan that lacks HS side chains had a marked reduction in the inhibition of in vitro SMC function and the in vivo arterial response to injury, indicating the critical role of HS side chains in perlecan function in the vessel wall.

Therapeutic angiogenesis with VEGF164 for facilitation of guidewire crossing in experimental arterial chronic total occlusions.

AIMS: Percutaneous revascularisation of chronic total occlusions (CTO) is limited by failure of guidewire crossing. Neovascularisation within the proximal CTO segment may be important for guidewire crossing and dramatically declines in CTO beyond six weeks of age. The aims of the current study were to determine whether local delivery of a pro-angiogenic growth factor increases neovascularisation in mature CTO and facilitates guidewire crossings. METHODS AND RESULTS: CTO (n=51) were created in the femoral arteries of 44 New Zealand white rabbits using the thrombin injection model. At 12 weeks, CTO were treated with poly-lactic-glycolic-acid (PLGA) microspheres containing either bovine serum albumin (BSA) (n=15) or recombinant mouse VEGF164 (n=14), or received no intervention (controls, n=12). Contrast-enhanced magnetic resonance angiography (CEMRA) was performed prior to treatment and at three weeks post treatment. Animals were sacrificed at three weeks post treatment and arterial samples were excised for micro-computed tomography imaging (µCT) and histologic morphometric analysis. Guidewire crossing was assessed at three weeks post treatment in an additional 10 VEGF164-treated CTO. In comparison to BSA-treated and control non-intervened CTO, VEGF164-treated CTO showed a significant increase in relative blood volume index in the proximal segment of the CTO lesion as determined by CEMRA and by µCT. Histologic measurements of microvessel area were also higher in VEGF164-treated CTO. Guidewire crossing across the proximal fibrous cap was successful in eight out of 10 VEGF164-treated CTO. CONCLUSIONS: Angiogenic therapy appears to be a promising strategy to improve neovascularisation and guidewire crossing rates in CTO.

Statin therapy prevents expansive remodeling in venous bypass grafts.

BACKGROUND: Venous grafts (VG) have high failure rates by 10 years in aortocoronary bypass surgery. We have previously shown that expansive remodeling followed by increased LDL retention are early atherosclerotic changes in experimental VG placed in the arterial circulation. The objective of this study was to determine whether statin therapy prevents these expansive remodeling changes. METHODS AND RESULTS: Reversed jugular vein-to-common carotid artery interposition graft was constructed in 27 cholesterol-fed (0.5%) rabbits. Rabbits were randomized either to control or atorvastatin (5 mg/kg/day) groups, starting two weeks prior to vein graft implantation and continuing until sacrifice at 1 or 12 weeks post-surgery. Ultrasound measurements of arterial luminal cross-sectional area (CSA) were done at day 3 and at 4, 8 and 12 weeks post-surgery. Histomorphometric measurements were performed following sacrifice at 12 weeks. Atorvastatin treatment significantly decreased total plasma cholesterol levels at 4, 8 and 12 weeks (12 weeks: 6.7 ± 4.2 mmol/L versus control 38.7 ± 10.6 mmol/L, p<0.0002). Atorvastatin significantly reduced expansive remodeling at 4, 8 and 12 weeks (lumen CSA: 44.6 ± 6.6 mm(2) versus control 77.6 ± 10.7 mm(2), p<0.0001). Intimal CSA by histomorphometry was also significantly reduced by atorvastatin at 12 weeks (5.59 ± 2.19 mm(2) versus control 9.57 ± 2.43 mm(2), p<0.01). VG macrophage infiltration, MMP-2 activity and metalloelastase activity were reduced in the atorvastatin treated group. CONCLUSION: Atorvastatin inhibits both expansive remodeling and intimal hyperplasia in arterialized VG, likely through inhibition of macrophage infiltration and reduction of tissue proteolytic activity. The mechanism proposed above may be important for preventing VG atherosclerosis and late VG failure.

Characterisation of a novel porcine coronary artery CTO model.

AIMS: To create a large animal coronary chronic total occlusion (CTO) model. Presence of microvessels within the CTO lumen facilitates guidewire crossing. The patterns and time profiles of matrix changes and microvessel formation during coronary CTO maturation are unknown. METHODS AND RESULTS: CTO were created in 15 swine by percutaneous deployment of a collagen plug. Matrix changes were assessed by histology. Intraluminal neovascularisation was assessed by histology and several imaging modalities, including conventional and 3D spin angiography, micro-computed tomography (micro-CT) imaging, and contrast-enhanced magnetic resonance imaging (MRI), at six and 12 weeks following CTO creation. Matrix changes included an intense inflammatory reaction at six weeks which had partially abated by 12 weeks. A proteoglycan-rich matrix at six weeks was partially replaced with collagen by 12 weeks. Similar changes were noted in the proximal cap which was acellular. Three patterns of microvessel formation were identified and defined based on the presence and extent of a "lead" neovessel. No major differences in pattern or extent of neovascularisation were noted between six and 12 weeks. CONCLUSIONS: Heterogeneity in neovascularisation patterns occurs during coronary CTO development in a porcine model. Non-invasive imaging to determine the predominant type of neovascularisation prior to and during CTO revascularisation may improve guidewire crossing success rates. This model may be useful for further exploration of CTO pathophysiology, and may aid in further refinements of in vivo imaging of CTO and development of novel therapeutic approaches to revascularisation of CTO, such as manipulations of the proximal cap, matrix composition, neovessel induction, and device testing.

Current perspectives on coronary chronic total occlusions: the Canadian Multicenter Chronic Total Occlusions Registry.

OBJECTIVES: The purpose of this study was to determine the prevalence, clinical characteristics, and management of coronary chronic total occlusions (CTOs) in current practice. BACKGROUND: There is little evidence in contemporary literature concerning the prevalence, clinical characteristics, and treatment decisions regarding patients who have coronary CTOs identified during coronary angiography. METHODS: Consecutive patients undergoing nonurgent coronary angiography with CTO were prospectively identified at 3 Canadian sites from April 2008 to July 2009. Patients with previous coronary artery bypass graft surgery or presenting with acute ST-segment elevation myocardial infarction were excluded. Detailed baseline clinical, angiographic, electrocardiographic, and revascularization data were collected. RESULTS: Chronic total occlusions were identified in 1,697 (18.4%) patients with significant coronary artery disease (>50% stenosis in ≥1 coronary artery) who were undergoing nonemergent angiography. Previous history of myocardial infarction was documented in 40% of study patients, with electrocardiographic evidence of Q waves corresponding to the CTO artery territory in only 26% of cases. Left ventricular function was normal in >50% of patients with CTO. Half the CTOs were located in the right coronary artery. Almost half the patients with CTO were treated medically, and 25% underwent coronary artery bypass graft surgery (CTO bypassed in 88%). Percutaneous coronary intervention was done in 30% of patients, although CTO lesions were attempted in only 10% (with 70% success rate). CONCLUSIONS: Chronic total occlusions are common in contemporary catheterization laboratory practice. Prospective studies are needed to ascertain the benefits of treatment strategies of these complex patients.

Decreased risk of stent fracture-related restenosis between paclitaxel-eluting stents and sirolimus eluting stents: results of long-term follow-up.

OBJECTIVE: To compare the outcomes between paclitaxel-eluting stents (PES) and sirolimus-eluting stents (SES) for the treatment of drug-eluting stent (DES) fracture. BACKGROUND: DES fracture is considered as an important predictor of in-stent restenosis (ISR). However, little data are available evaluating the optimal treatment for this complication of coronary stenting. METHODS: From January 1, 2004 to December 31, 2008, patients with DES ISR treated with a second DES were identified and evaluated for stent fracture. Stent fracture was defined by the presence of strut separation in multiple angiographic projections, assessed by two independent reviewers. Target lesion revascularization (TLR) at 6 and 12 months were the primary end points. RESULTS: Of 131 lesions with DES ISR treated with a second DES, we found 24 patients (24 lesions, 18.2%) with angiographically confirmed stent fracture. Of these, 20 patients (20 lesions) treated with either PES (n = 11/55%) or SES (n = 9/45%) were included in the study. TLR at 6 months occurred in 9% of patients treated with PES and 22% of those treated with SES (P = 0.41). After 12 months, TLR was 9% and 55.5%, respectively (P = 0.024). CONCLUSIONS: This study demonstrates a high incidence of stent fracture in patients presenting with DES ISR in need of further treatment with another DES. The suggested association between treatment of stent fracture-associated DES ISR with PES as compared with SES, and better long-term outcomes, is in need of confirmation by larger prospective registries and randomized trials.

Collagenase Total Occlusion-1 (CTO-1) trial: a phase I, dose-escalation, safety study.

BACKGROUND: Percutaneous interventions for chronic total occlusions have low success rates, primarily because of failure of guide wire crossing. Collagen-rich matrix constitutes the main barrier to chronic total occlusion crossing. In preclinical studies, local delivery of a bacterial collagenase formulation improved guide wire crossing. The Collagenase Total Occlusion-1 (CTO-1) Trial is a phase I, dose-escalation trial to assess the safety and efficacy of collagenase therapy to facilitate guide wire crossing in coronary artery chronic occlusions. METHODS AND RESULTS: Twenty subjects with ≥1 previous failure of chronic total occlusion guide wire crossing were enrolled at 2 sites. Subjects were treated in 4 distinct cohorts of 5 patients, with escalation of collagenase dose in each cohort from 300 to 1200 µg. Collagenase was locally delivered into the occlusions with either an over-the-wire balloon system (n=8) or a fine-cross microcatheter (n=12) for a period of 30 minutes. Subjects were brought back to the catheterization laboratory for guide wire crossing and angioplasty the next day. Guide wire crossing was successfully achieved in 15 subjects (75%). A soft-tip guide wire (Whisper, Pilot-50, Fielder XT) was either the sole or predominant guide wire used in 75% of successful crossings. Non-ST-segment-elevation myocardial infarctions occurred in 3 patients as a result of side-branch ischemia during stenting. Computed tomographic angiography at 3 months showed no late complications and patent stents in successfully treated chronic total occlusion. Anginal improvement occurred with a reduction in Canadian Cardiovascular Society class from baseline to 3 months (2.5±0.6 versus 0.9±0.9; P<0.001). CONCLUSION: Local delivery of collagenase into coronary chronic total occlusion is feasible and safe with encouraging guide wire crossing results in previously failed cases. Larger clinical trials are required to determine efficacy. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01271335.