Coronary Guidewire Research Articles

Index of Microcirculatory Resistance Measured during Intracoronary Adenosine-Induced Hyperemia.

Background The index of microcirculatory resistance is an invasive measure of coronary microvascular function that has to be calculated during maximal hyperemia, classically achieved with intravenous adenosine (IV). The aim of this study was to evaluate the use of intracoronary (IC) adenosine for the calculation of IMR. Methods and Results 31 patients with stable coronary artery disease were included in the study. Coronary pressure and thermodilution measurements were obtained at rest and during maximal hyperemia using a pressure-temperature sensor-tipped coronary guidewire. Duplicate measurements were performed using first IC and then IV adenosine. Dispersion of transit times was comparable for IC and IV adenosine. IMR values based on IC vs IV adenosine showed a high level of agreement and an intraclass correlation coefficient of 0.90. Applying an upper normal limit of 25, misclassification of IMR using IC adenosine was seen in just one patient in whom IC adenosine resulted in a lower value. A simplified procedure based on a single bolus dose of saline did not change the level of agreement or the rate of misclassification. Conclusions We found an excellent agreement between IMR values measured during hyperemia induced by IC as compared to IV adenosine. The use of IC adenosine may facilitate invasive assessment of microvascular function and is potentially time- and cost-saving with less patient discomfort as compared to IV infusion. The trail is registered with NCT03369184.

A way to find of the hard-to-reach and Risky Locations Arrhythmia Focus: Double Coronary Guidewire Mapping Technique.

A way to find of the hard-to-reach and Risky Locations Arrhythmia Focus: Double Coronary Guidewire Mapping Technique.

Induction of left ventricular hypoplasia by occluding the foramen ovale in the fetal lamb

Disturbed fetal haemodynamics often affects cardiac development and leads to congenital cardiac defects. Reduced left ventricular (LV) preload in the fetus may result in hypoplastic LV, mitral and aortic valve, mimicking a moderate form of hypoplastic left heart complex. We aimed to induce LV hypoplasia by occluding the foramen ovale (FO) to reduce LV preload in the fetal sheep heart, using percutaneous trans-hepatic catheterisation. Under maternal anaesthesia and ultrasound guidance, hepatic venous puncture was performed in six fetal lambs (0.7–0.75 gestation). A coronary guidewire was advanced into the fetal inferior vena cava, right and left atrium. A self-expandable stent was positioned across the FO. An Amplatzer Duct Occluder was anchored within the stent for FO occlusion. Euthanasia and post-mortem examination was performed after 3 weeks. Nine fetuses were used as age-matched controls. Morphometric measurements and cardiac histopathology were performed. Compared with controls, fetal hearts with occluded FO had smaller LV chamber, smaller mitral and aortic valves, lower LV-to-RV ratio in ventricular weight and wall volume, and lower number of LV cardiomyocyte nuclei. We conclude that fetal FO occlusion leads to a phenotype simulating LV hypoplasia. This large animal model may be useful for understanding and devising therapies for LV hypoplasia.

Rationale and design of the British Heart Foundation (BHF) Coronary Microvascular Function and CT Coronary Angiogram (CorCTCA) study

BackgroundMicrovascular and/or vasospastic anginas are relevant causes of ischemia with no obstructive coronary artery disease (INOCA) in patients after computed tomography coronary angiography (CTCA).ObjectivesOur research has 2 objectives. The first is to undertake a diagnostic study, and the second is to undertake a nested, clinical trial of stratified medicine.DesignA prospective, multicenter, randomized, blinded, sham-controlled trial of stratified medicine (NCT03477890) will be performed. All-comers referred for clinically indicated CTCA for investigation of suspected coronary artery disease (CAD) will be screened in 3 regional centers. Following informed consent, eligible patients with angina symptoms are enrolled before CTCA and remain eligible if CTCA excludes obstructive CAD.Diagnostic study: Invasive coronary angiography involving an interventional diagnostic procedure (IDP) to assess for disease endotypes: (1) angina due to obstructive CAD (fractional flow reserve ≤0.80); (2) microvascular angina (coronary flow reserve <2.0 and/or index of microvascular resistance >25); (3) microvascular angina due to small vessel spasm (acetylcholine); (4) vasospastic angina due to epicardial coronary spasm (acetylcholine); and (5) noncoronary etiology (normal coronary function). The IDP involves direct invasive measurements using a diagnostic coronary guidewire followed by provocation testing with intracoronary acetylcholine. The primary outcome of the diagnostic study is the reclassification of the initial CTCA diagnosis based on the IDP.Stratified medicine trial: Participants are immediately randomized 1:1 in the catheter laboratory to therapy stratified by endotype (intervention group) or not (control group). The primary outcome of the trial is the mean within-subject change in Seattle Angina Questionnaire score at 6 months.Secondary outcomes include safety, feasibility, diagnostic utility (impact on diagnosis and certainty), and clinical utility (impact on treatment and investigations). Health status assessments include quality of life, illness perception, anxiety-depression score, treatment satisfaction, and physical activity. Participants who are not randomized will enter a follow-up registry. Health and economic outcomes in the longer term will be assessed using electronic patient record linkage.ValueCorCTCA will prospectively characterize the prevalence of disease endotypes in INOCA and determine the clinical value of stratified medicine in this population.

Retained Coronary Guidewire Extending to the Right Axillary Artery

This is a case of a 56-year-old female who presented with inferior ST segment elevation myocardial infarction (STEMI), treated with percutaneous intervention (PCI), which was complicated by a retained guidewire extending from left circumflex artery (at location of obtuse marginal (OM) stent) through the ascending aorta, the right brachiocephalic artery and into the right axillary artery. Patient underwent cardiac CT, with maximum intensity projection image showing the course of the retained guidewire. Percutaneous retrieval was deferred due to risk of damaging the stent, and the patient initially deferred coronary artery bypass (CABG) and surgical retrieval as. She was discharged on triple therapy with Aspirin, Clopidogril and Apixaban for 3 months with no bleeding or thromboembolic complications on a 3-month follow up with cardiology clinic, during which rediscussion of risks and benefits of CABG and surgical retrieval or retained wire took place with the patient. Patient agreed to undergo the procedure and guidewire was retrieved surgically and CABG was done. [Display omitted]

P1769Microvascular resistance increases with left ventricular mass in hypertrophic cardiomyopathy

Abstract Introduction Hypertrophic cardiomyopathy is often associated with myocardial ischemia despite lack of focal epicardial coronary stenoses and this is partially attributable to microvascular dysfunction. The index of microvascular resistance (IMR) is a hemodynamic index that is independent of epicardial stenoses and reflects coronary microvascular function. Purpose To investigate the relationship between microvascular dysfunction and the degree of hypertrophy in hypertrophic cardiomyopathy patients. Methods We performed a prospective study to assess epicardial and microvascular coronary hemodynamics in 12 subjects with hypertrophic cardiomyopathy undergoing diagnostic coronary angiography. A pressure-temperature sensor coronary guidewire was used with intracoronary injections of room-temperature saline to measure mean coronary transit time during rest and hyperemia induced with intravenous adenosine. IMR was calculated by multiplying mean coronary transit time during hyperemia by distal coronary pressure in each subject. Left ventricular mass was calculated from baseline echocardiographic studies using established methods. Continuous variables are shown as mean ± standard deviation. Results Six subjects were male; mean age was 59.8±11.6 years. Baseline body mass index was 30.5±6.1 kg/m2 and left ventricular ejection fraction was 76.7% ± 11.0% with mean left ventricular mass 230.1±76.6 grams by echocardiography. Ten subjects had asymmetric septal hypertrophy; one subject had marked apical hypertrophy and one subject had asymmetric septal and inferolateral hypertrophy. Resting left ventricular outflow tract gradient was 59.4±37.8 mmHg and increased to 90.0±54.1 mmHg with Valsalva maneuver. Systolic anterior motion of the mitral valve was present in 10 subjects. Hemodynamic variables included coronary flow reserve (2.1±1.2); hyperemic mean transit time (0.29±0.15 sec.), and IMR (21.7±10.2). Index of microvascular resistance was strongly positively correlated with left ventricular mass (Figure 1; Pearson r=0.68, p=0.021). Figure 1. IMR is correlated with LV mass Conclusion(s) Microvascular dysfunction as assessed by IMR is strongly correlated with left ventricular mass and may contribute to symptoms in patients with hypertrophic cardiomyopathy.

INVASIVE ASSESSMENT OF MICROVASCULAR RESISTANCE IN HYPERTROPHIC CARDIOMYOPATHY WITH ECHOCARDIOGRAPHIC CORRELATES

Introduction Hypertrophic cardiomyopathy (HCM) is often associated with ischaemia despite lack of focal epicardial coronary stenosis. Our aim was to assess invasive coronary microvascular circulation and correlate findings with echocardiography. Methods We prospectively enrolled patients with HCM and controls who were referred for diagnostic coronary angiography. A pressure-temperature sensor coronary guidewire was used with intracoronary injections of room-temperature saline to measure mean coronary transit time during rest and hyperaemia induced with intravenous adenosine. The index of microvascular resistance (IMR) was calculated. Left ventricular mass was calculated during echocardiographic studies. Results Patients with HCM (n=12) and controls (n=7), had similar demographics. Left ventricular ejection fraction was higher in HCM (76.7%±11.0% vs 55.0%±15.9%, p=0.003). IMR was non-significantly higher in HCM (21.7±10.2 vs 15.3±4.8, p=0.16). Only patients with HCM had abnormal IMR (>25). Coronary flow reserve was non-significantly higher in HCM (2.7±1.6 vs 2.1±1.2, p=0.34). IMR correlated with left ventricular mass in hypertrophic cardiomyopathy subjects (Pearson r=0.68, p=0.02). Conclusions Microvascular dysfunction as assessed by IMR may be abnormal in HCM and is correlated with left ventricular mass.

Teknik Rapor: Koroner Teller Kullanılarak Kalbin Değişik Bölgelerinden Temiz ve Gürültüsüz Bipolar Kayıtlar Alınması

Teknik Rapor: Koroner Teller Kullanılarak Kalbin Değişik Bölgelerinden Temiz ve Gürültüsüz Bipolar Kayıtlar Alınması

Ultra-low-contrast angiography in patients with advanced chronic kidney disease and previous coronary artery bypass surgery.

We sought to describe a technique for ultra-low-contrast angiography (ULCA) in patients with advanced chronic kidney disease (CKD) and previous coronary artery bypass surgery (CABG). Patients with advanced CKD and previous CABG are at high risk of developing contrast-induced nephropathy (CIN) because of the additional contrast often required to identify bypass grafts. Apart from hydration, reduced contrast administration is the only established method to minimize the risk of CIN. Ten patients underwent ULCA, whereby an intracoronary injection of saline and coronary guidewires were used instead of test injections of contrast for engagement of bypass grafts with catheters. Estimated glomerular filtration rate (eGFR) before and 30 days following angiography were recorded as was the need for renal replacement therapy 1 year after the procedure. All patients completed a diagnostic angiogram without complications. The median volume of contrast delivered was 13.5 ml (interquartile range: 10.5-17.8). The median eGFR was 18.3 ml/min/1.73 m (interquartile range: 16.5-28.2). There was no statistically significant difference in eGFR before the procedure and 30 days after the procedure (P=0.79). No patient required dialysis 30 days after the procedure. Two patients required initiation of dialysis at 1 year after the procedure. In patients with advanced CKD and previous CABG, ULCA may be performed with high procedural success and without complications, minimizing the risk of CIN in these high-risk patients.

Novel porcine model of acute myocardial infarction using polyethylene terephthalate

Acute myocardial infarction (AMI) is considered the major cause of mortality in the world. Tremendous animal studies are performed to develop novel therapeutics, and this study aimed to induce porcine myocardial infarction model by using polyethylene terephthalate (PET). Coronary guidewire was placed in left anterior descending artery (LAD). The balloon angioplasty catheter was inserted at the back of the PET. The balloon catheter was carefully pushed forward, until the balloon marker was located in mid-LAD. Coronary angiography was performed pre- and post-occlusion at 28 days by C-arm. Histologic analysis of heart tissue was performed 28 days after inducing AMI. Thirty three pigs were anesthetized and underwent percutaneous coronary catheterization. All pigs were successfully embolized in mid-LAD by PET. Fifteen pigs died due to ventricular fibrillation during post-anesthetic recovery time, and overall experiment mortality was 45.5%. In 2,3,5-triphenyl tetrazolium chloride staining, gross finding of the ischemic heart lesion showed firm and white area of infarction associated with the apex and left ventricular posterior wall. Infarct on H&amp;E-stained sections demonstrated a region without myocytes and rich with cardiomyocyte with atypical nuclei. Successful induction of AMI by using PET may provide the pathophysiological information of ischemic heart disease and improvement of therapy development for AMI.

Microcatheter-assisted stenting of the tortuous vertical ductus arteriosus via femoral access in a duct-dependent pulmonary circulation

BackgroundStenting of the patent ductus arteriosus (PDA) has been accepted as alternative option to surgical shunting to enable additional pulmonary blood flow or for palliation of patients with a truly duct-dependent pulmonary circulation. The procedure can be challenging given the variable and often tortuous anatomy of the PDA and various technical approaches are reported. ObjectiveTo report an alternative technique to treat tortuous ducts with microcatheter assistance and by transfemoral approach. MethodsWe applied this technique of PDA stenting in 5 consecutive patients (4/5 age < 1 week, weight 2,7–3,2 kg; 1/5 re-do PDA stenting at 6,5 month and 5,9 kg). A soft coronary guidewire was advanced by microcatheter assistance into the branch pulmonary arteries and thereafter replaced by an extrastiff guidewire to enable the placement of long coronary stents. ResultsSuccessful PDA stenting with this stepwise approach and with femoral access only could be achieved in all patients (n = 5/5). A single stent was used in 2 patients (one with re-do stenting and previous stents). 3/5 patients had 2 stents implanted by telescopic technique. Stent sizes used were 4,5 × 15 mm (n = 2) and 4,5 × 18 mm (n = 6). No guide wire or stent dislodgement appeared through all procedures with microcatheter assistance. ConclusionsThis technique enables PDA stenting via transfemoral approach in complex and tortuous ducts and thereby offers an attractive addition to the interventional management of truly duct-dependent pulmonary circulation.

P022] Assessment of the detectability of a moving guidewire in fluoroscopically-guided procedures using a mathematical model observer

Purpose Fluoroscopically-guided procedures are among the most irradiating medical interventions. Thus, a fair amount of pressure is put on reducing patient exposure. This can be achieved by adapting the unit’s protocols, and by using technical upgrades. However, it is important to check if any image information content is lost. To our knowledge, there is no existing metric able to objectively assess the detectability of moving structures in fluoroscopic images. This work proposes a new method to assess image quality for a clinically relevant detection task in dynamic conditions using a mathematical observer. Methods A thin PMMA plate, supporting a 0.014” guidewire, was attached to a motion simulation engine via a cantilever, allowing motion with velocities and amplitudes representative of coronary arteries. The guidewire was placed at the unit’s isocenter, while 20 cm of PMMA around it simulated a patient. Images were acquired using pre-defined fluoroscopy quality levels (low, medium, and high) on two different units: One dedicated for interventional cardiology (IC), (Philips AlluraClarity FD10) the other for a broader purpose range (Philips Veradius Neo). Regions of interest were extracted from the images, either in the homogenous zones (signal-absent), or along the guidewire (signal-present). A mathematical model observer computed a decision variable for each signal-absent and signal-present image. The signal-to-noise ratio (SNR) between both decision variable distributions was taken as the figure of merit of the guidewire detectability. Dose rates were measured at the entrance of the PMMA using a pencil ionisation chamber. Results Preliminary results show that, for the IC unit, the SNR is equal to 3.5, 4.1 and 4.9 for respectively low (reference dose rate), medium (×1.6 rate) and high (×3.7 rate) quality fluoroscopy settings. In comparison, the same measurement on the non IC-dedicated unit yields a SNR of only 2.0 (high quality setting), at a dose rate comparable (11.5 vs. 12.2 mGy min−1) to medium quality fluoroscopy on the IC unit. Conclusions We have shown the feasibility of using a model observer to assess the detectability of a moving coronary guidewire. Further developments will include the fine tuning of the model, and matching between human observer results.

The effects of types of guidewires and pressure applied during stent implantation in the main vessel on the incidence of damage to coronary guidewires during angioplasty of coronary bifurcation lesions-Wide Beast study.

We evaluated the impact of stent inflation pressure and type of guidewire on "jailed" coronary guidewire damage occurring during bifurcation angioplasty. Despite new techniques and treatment options during percutaneous coronary intervention (PCI) we still observe peri- and postoperative complications for to various known and unknown reasons. Patients undergoing PCI within the coronary bifurcation were randomly assigned to one of four groups: Pilot 50 or BMW guidewire and pressure ≤12 or >12 atm. After PCI each "jailed" guidewire was evaluated under an optical microscope. The Wide Beast Scale (WBS) was developed for the internal purposes of the study and was used for qualitative assessment. Also, the inflation pressure, the patients' characteristics and the technical parameters of the procedure were recorded. The clinical characteristics were similar in all the groups. There was no statistical significance of the degree of damage, rated on the WBS, for either guidewire group with respect to inflation pressure (P = 0.49). The prevalence of guidewire damage was higher in the BMW versus the Pilot 50 group (98.4% vs 67.4% respectively, P = 0.00001) as was the severity of the damage (grades 3 and 4) in BMW versus Pilot 50 (55.6% vs 13.0% respectively, P = 0.00001). The inflation pressure during stent implantation had no impact on "jailed" guidewire damage. The difference in the prevalence of serious damage and total damage number was statistically significant for the BMW guidewire compared to the Pilot50. The BMW guidewire was an independent predictor of the degree of damage to the guidewire.

The relationship between segmental wall shear stress and lipid core plaque derived from near-infrared spectroscopy

Background and aimsWall shear stress (WSS) has an important role in the natural history of coronary atherosclerosis. The aim of this study is to investigate the relationship between WSS and the lipid content of atherosclerotic plaques as assessed by near-infrared spectroscopy (NIRS). MethodsWe performed serial NIRS and intravascular ultrasound (IVUS) upon Doppler coronary flow guidewire of coronary plaques at baseline and after 12–18 months in 28 patients with <30% angiographic stenosis, who presented with coronary artery disease. Segmental WSS, plaque burden and NIRS-derived lipid rich plaque (LRP) were evaluated at both time-points in 482 consecutive 2-mm coronary segments. ResultsSegments with LRP at baseline (n = 106) had a higher average WSS (1.4 ± 0.6 N/m2), compared to those without LRP (n = 376) (1.2 ± 0.6 N/m2, p<0.001). In segments without baseline LRP, WSS was higher in those who subsequently developed new LRP (n = 35) than those who did not (n = 341) (1.4 ± 0.8 vs. 1.1 ± 0.6 N/m2, p=0.002). Conversely, in segments with baseline LRP, WSS was lower in those who had regression of lipid content (n = 41) than those who did not (n = 65) (1.2 ± 0.4 vs. 1.6 ± 0.7 N/m2, p=0.007). Segments with the highest tertile of WSS displayed greater progression of LCBI irrespective of baseline lipid content (p<0.001). Multivariate analysis revealed that baseline WSS (p=0.017), PAV (p<0.001) and LCBI (p<0.001) were all independent predictors of change in LCBI over time. ConclusionsCoronary segments with high WSS associate with progression of lipid content over time, which may indicate transformation to a more vulnerable phenotype.

Electrocardiogram-synchronized pulsatile extracorporeal life support preserves left ventricular function and coronary flow in a porcine model of cardiogenic shock.

IntroductionVeno-arterial extracorporeal life support (ECLS) is increasingly being used to treat rapidly progressing or severe cardiogenic shock. However, it has been repeatedly shown that increased afterload associated with ECLS significantly diminishes left ventricular (LV) performance. The objective of the present study was to compare LV function and coronary flow during standard continuous-flow ECLS support and electrocardiogram (ECG)-synchronized pulsatile ECLS flow in a porcine model of cardiogenic shock.MethodsSixteen female swine (mean body weight 45 kg) underwent ECLS implantation under general anesthesia and artificial ventilation. Subsequently, acute cardiogenic shock, with documented signs of tissue hypoperfusion, was induced by initiating global myocardial hypoxia. Hemodynamic cardiac performance variables and coronary flow were then measured at different rates of continuous or pulsatile ECLS flow (ranging from 1 L/min to 4 L/min) using arterial and venous catheters, a pulmonary artery catheter, an LV pressure-volume loop catheter, and a Doppler coronary guide-wire.ResultsMyocardial hypoxia resulted in declines in mean cardiac output to 1.7±0.7 L/min, systolic blood pressure to 64±22 mmHg, and LV ejection fraction (LVEF) to 22±7%. Synchronized pulsatile flow was associated with a significant reduction in LV end-systolic volume by 6.2 mL (6.7%), an increase in LV stroke volume by 5.0 mL (17.4%), higher LVEF by 4.5% (18.8% relative), cardiac output by 0.37 L/min (17.1%), and mean arterial pressure by 3.0 mmHg (5.5%) when compared with continuous ECLS flow at all ECLS flow rates (P<0.05). At selected ECLS flow rates, pulsatile flow also reduced LV end-diastolic pressure, end-diastolic volume, and systolic pressure. ECG-synchronized pulsatile flow was also associated with significantly increased (7% to 22%) coronary flow at all ECLS flow rates.ConclusionECG-synchronized pulsatile ECLS flow preserved LV function and coronary flow compared with standard continuous-flow ECLS in a porcine model of cardiogenic shock.

TCTAP C-197 Optical Coherence Tomography Defined Plaque Erosion After Removal of Coronary Guidewire

### Patient Initials or Identifier Number CGP ### Relevant Clinical History and Physical Exam A 45 years-old man visited outpatient room with exercise induced chest pain. Chest pain developed during climbing 3 months ago and occurred during exercise for 30 minutes on the day of visit. He had no

Transcatheter pledget-assisted suture tricuspid annuloplasty (PASTA) to create a double-orifice valve.

Pledget-assisted suture tricuspid valve annuloplasty (PASTA) is a novel technique using marketed equipment to deliver percutaneous trans-annular sutures to create a double-orifice tricuspid valve. Tricuspid regurgitation is a malignant disease with high surgical mortality and no commercially available transcatheter solution in the US. Two iterations of PASTA were tested using trans-apical or trans-jugular access in swine. Catheters directed paired coronary guidewires to septal and lateral targets on the tricuspid annulus under fluoroscopic and echocardiographic guidance. Guidewires were electrified to traverse the annular targets and exchanged for pledgeted sutures. The sutures were drawn together and knotted, apposing septal and lateral targets, creating a double orifice tricuspid valve. Twenty-two pigs underwent PASTA. Annular and chamber dimensions were reduced (annular area, 10.1 ± 0.8 cm2 to 3.8 ± 1.5 cm2 (naïve) and 13.1 ± 1.5 cm2 to 6.2 ± 1.0 cm2 (diseased); septal-lateral diameter, 3.9 ± 0.3 mm to 1.4 ± 0.6 mm (naïve) and 4.4 ± 0.4 mm to 1.7 ± 1.0 mm (diseased); and right ventricular end-diastolic volume, 94 ± 13 ml to 85 ± 14 ml (naïve) and 157 ± 25 ml to 143 ± 20 ml (diseased)). MRI derived tricuspid regurgitation fraction fell from 32 ± 12% to 4 ± 5%. Results were sustained at 30 days. Pledget pull-through force was five-fold higher (40.6 ± 11.7N vs 8.0 ± 2.6N, P < .01) using this strategy compared to single puncture techniques used to anchor current investigational devices. Serious complications were related to apical access. PASTA reduces annular dimensions and tricuspid regurgitation in pigs. It may be cautiously applied to selected patients with severe tricuspid regurgitation and no options. This is the first transcatheter procedure, to our knowledge, to deliver standard pledgeted sutures to repair cardiac pathology.

Surgical retrieval of entrapped coronary guidewire remnant - 3-year angiographic evaluation.

Surgical retrieval of entrapped coronary guidewire remnant - 3-year angiographic evaluation.

PULL STRAIGHTEN AND PUSH TECHNIQUE: A SIMPLE SOLUTION FOR GUIDEWIRE REALIGNMENT TO FACILITATE STENT AND DEVICE DELIVERY IN CORONARY ANGIOPLASTY

Coronary guidewire bias prevents easy passage of interventional devices such as stents and balloons during percutaneous coronaryintervention (PCI). Realigning guidewire into the central part of the lumen, away from the coronary wall helps the tracking devicesin situations with significant guidewire bias. There are several available techniques to facilitate stent delivery in tortuous vessel;however, these techniques have their own limitations and can be expensive and time-consuming. A new maneuver for easy passageof stents and balloons in these situations by guidewire realignment is described in this report. This maneuver namely “pull straightenand push technique” demonstrated an easy procedure to successfully execute stents or devices deployment in challenging PCIs.

Spontaneous rotation of the monorail-type guide extension support catheter during advancement of a curved guiding catheter: the potential hazard of twisting with the coronary guidewire

The extension support guiding catheter has been used to perform complex percutaneous coronary intervention to increase back-up support for the guiding catheter or to ensure deep intubation for device delivery. However, because of its monorail design, advancement of the stent into the distal extension tubing segment is sometimes problematic. Although this problem is considered due to simple collision of the stent, operators have observed tangling between a monorail extension catheter and coronary guidewire in some patients. To examine movement of the collar of the extension guide catheter during advancement of the guiding catheter, we set up an in vitro model in which the guiding catheter had two curves. Rotation of the extension guide catheter was examined by both fluoroscopic imaging and movement of the hub of the proximal end of the catheter. During advancement in the first curve, the collar moved toward the outer side of the curve of the guiding catheter as the operator pushed the shaft of the extension guiding catheter, which overrode the guidewire. After crossing the first curve, the collar moved again to the outer side of the second curve (the inner side of the first curve) of the mother catheter, and then, another clockwise rotation was observed in the proximal hub. Consequently, the collar and tubing portion of the extension guide catheter rotated 360° around the coronary guidewire, and the monorail extension catheter and guidewire became tangled. There is a potential risk of unintentional twisting with the guidewire during advancement into the curved guiding catheter because of its monorail design.