Research Update

The following research abstracts are reprinted with permission from The Journal of Invasive Cardiology, Vol. 17, No. 9 (September 2005)
The following research abstracts are reprinted with permission from The Journal of Invasive Cardiology, Vol. 17, No. 9 (September 2005)
Adjunctive Therapy Angiographic and Intravascular Ultrasound Findings of the Late Catch-Up Phenomenon after Intracoronary Beta-Radiation for the Treatment of In-Stent Restenosis Authors: Fausto Feres, Juan Munoz, Alexandre Abizaid, Rodolfo Staico, Mirtes Kuwabara, Luiz Mattos, Marinella Centemero, Galo Maldonado, Mariano Albertal, Vinicius D. Vaz, Eduardo Ferreira, Luiz F. Tanajura, Aurea Chaves, Amanda Sousa, J. Eduardo Sousa We report one-year angiographic and intravascular ultrasound (IVUS) outcomes of in-stent restenosis (ISR) patients treated with intravascular brachytherapy (IVBT). The benefit of IVBT for treating ISR is well documented. However, few data exist on significant angiographic and intravascular ultrasonic in-stent lumen deterioration beyond the habitual 6-month analysis after the index radiation procedure or so-called late catch-up process in the treatment of ISR. Twenty-five consecutive patients with ISR were treated with IVBT using the Beta-Cath System (a 40 mm 90 Sr/90 gamma source). Quantitative angiographic and IVUS analysis was performed in all of them at 6 and 12 months. IVBT was successful in all patients. Four patients (16%) developed recurrent angiographic binary restenosis at 6-month follow-up, all located within the adjacent reference segments, with 2 being associated with geographical miss. An additional 4 patients (16%) presented with recurrent ISR at 12-month follow-up, all within the stented segment. Significant in-stent lumen loss (0.16 ± 0.42 mm to 0.34 ± 0.46 mm; p = 0.008) and in-stent intimal hyperplasia growth (+11.2 ± 0.48 mm3; p = 0.03) was observed between 6 and 12 months. Intracoronary beta-radiation for the treatment of ISR was associated with significant luminal deterioration (late catch-up) within the stents between 6 and 12 months due to an important late progression of in-stent intimal hyperplasia. (J Invasive Cardiol 2005;17:473-477) Contrast Media Efficacy and Safety of Contrast Injection Beyond Total Occlusions in Acute Cardiac Patients: A Method to Confirm Balloon Position within Coronary Lumen Authors: Simcha R. Meisel, Aaron Frimerman, Aya Osipov, Avraham Shotan, David S. Blondheim, Benny Pelled, Jacob Shani Objectives: To evaluate the sensitivity and safety of contrast injection beyond total occlusions in acute cardiac patients in order to ensure balloon position within the coronary lumen and occasionally to enable the estimate of occlusion length. Background: Percutaneous therapy of total coronary occlusions is generally more challenging than the treatment of stenotic lesions. It more frequently entails the risk of irreversibly disrupting a protruding plaque, of advancing the wire through a false route, or rarely, of causing coronary perforation. Therefore, ascertaining intraluminal position prior to inflation is important. Methods: In a large group of consecutive acute cardiac patients undergoing percutaneous coronary intervention (PCI) we employed a technique of crossing the lesion with a soft-tipped guidewire supported by an over-the-wire (OTW) balloon catheter, and then injecting dilute contrast through the balloon under fluoroscopy to achieve distal lumen visualization. Results: In 106 patients, this technique yielded a sensitivity of 94%, a specificity of 70%, a positive predictive accuracy of 97%, and a negative predictive accuracy of 54% for intraluminal position of the balloon. Conclusions: The technique of lumen demonstration by contrast injection through an OTW balloon beyond acute or subacute total obstructions was shown to be a safe and effective method to ascertain proper position of the angioplasty balloon. Occasionally, it enabled the estimation of lesion length or the identification of lesions distal to the obstruction. This technique was found to be valuable in doubtful situations where the determination of wire position was crucial for achieving procedural success. (J Invasive Cardiol 2005;17:455-458) Hemostasis Hemostatic Efficacy of Hydrophilic Wound Dressing after Transradial Catheterization Authors: Eui-Young Choi, Young-Guk Ko, Jin-Bae Kim, Jihyuk Rhee, Sungha Park, Donghoon Choi, Yangsoo Jang, Won-Heum Shim, Sueng-Yun Cho Here, we evaluate the efficacy of the Clo-Sur PAD nonwoven hydrophilic wound dressing (HWD) on hemostasis in an arterial-access site after transradial percutaneous coronary angiography compared with the RadiStop compression device (CD). Eighty patients who had undergone transradial coronary angiography with or without intravascular ultrasound were randomly assigned to the HWD or CD group. The time required to achieve hemostasis was measured, and the incidence of vascular complications was assessed. No significant differences in clinical and procedural characteristics were observed between the HWD group (n = 40) and the CD group (n = 40). A significant reduction in the time required to achieve hemostasis (58.7 ± 32.6 minutes versus 131.3 ± 59.1 minutes; p J Invasive Cardiol 2005;17:459-462) Chronic Total Occlusions A New Percutaneous Porcine Coronary Model of Chronic Total Occlusion Authors: Woohyuk Song, Jaeung Lee, Hyunjoong Kim, Jinho Shin, Dongjoo Oh, Fermin Tio, S. Chiu Wong, Mun K. Hong Objective: Chronic total occlusion (CTO) of coronary arteries represents a challenge for percutaneous treatment. Although ameroid constrictors have been used to create CTOs from extrinsic compression of coronary arteries, this model is not suitable for evaluation of novel angioplasty equipment. Thus, the objective of this study was to create a new percutaneous animal model of CTO. Methods: To create an animal model of CTO, we implanted copper-plated stents in the left circumflex coronary arteries of 18 pigs, and assigned the pigs to early group (n = 6; sacrifice at 1 week), intermediate group (n = 6; sacrifice at 4 weeks), and late group (n = 6; sacrifice at 8 weeks). Results: Follow-up angiography prior to sacrifice revealed complete occlusion in 14/17 animals, with the subtotal occlusive lesions (mean 60% stenosis) only in the early group. Most of the pigs with total occlusions (12/14) showed bridging collateral flow ? grade 2 (grade 2: 4; grade 3: 8). Histology revealed organizing thrombus in the early group with persistent inflammation, and organized thrombus with fibrosis and calcification in the intermediate and late groups. Interestingly, there were fibrotic components in the proximal and distal edges of the occlusions with softer, organizing thrombus in the middle of the CTO in the late group, suggesting that the major areas of difficulty are at the entrance and exit segments of the CTO with percutaneous recanalization. Conclusion: This study shows the feasibility and reproducibility of a new porcine coronary percutaneous CTO model. This model may be useful in improving our percutaneous treatment of CTO. (J Invasive Cardiol 2005;17:452-454) Peripheral Vascular Disease The SPIDER Embolic Protection Device Performance Evaluation in the Carotid Artery During Percutaneous Transluminal Angioplasty and/or Stenting Author: Alberto Cremonesi Recently completed studies have compared carotid endarterectomy with carotid artery stenting, a nonsurgical method of improving blood flow in the carotid arteries. Embolic protection devices can prevent particles dislodged during carotid artery stenting from causing stroke or death. An ev3 Inc.-sponsored trial (PROTECT) evaluated the performance requirements of the SPIDER Embolic Protection Device in the carotid artery for CE Marking. Patients who were candidates for percutaneous transluminal angioplasty (PTA) and/or stenting were enrolled. Performance was assessed by determining the incidence of major adverse neurological events (MANE) through 30 days postprocedure in 74 patients, along with the successful placement and recovery rates of the filter. MANE was defined as stroke and death. There were a total of 5 MANE events reported in 5 patients, 1 major stroke and 4 minor strokes. There were no deaths. The total MANE event rate was 6.8% (5/73). The overall SAE rate was 8.2% (6/73). An SAE was defined as an event that resulted in the hospitalization or prolongation of hospitalization due to potential disability, or due to danger of life that resulted in an intervention or that was terminal. Technical success of the SPIDER device was defined as placement of the filter at the distal edge of the lesion in the carotid artery, placement of the recovery catheter and successful retrieval of the filter with the recovery catheter. An inability to place or retrieve the filter was concluded to be a system failure. The SPIDER device was successfully placed in the carotid artery and retrieved with an overall successful placement rate of 88.1% (74/84), and a retrieval rate of 98.6% (73/74). In conclusion, the PROTECT Trial demonstrated that the performance of the SPIDER device in the carotid artery complied with the relevant Product Directives for CE Marking. The incidence of MANE was low and comparable to what has been reported in recently published literature. (J Invasive Cardiol 2005;17:463-467) Arterial Kink and Damage in Normal Segments of the Superficial Femoral and Popliteal Arteries Abutting Nitinol Stents A Common Cause of Late Occlusion and Restenosis? A Single-Center Experience Author: Frank J. Arena Objective: To identify a new angiographic parameter associated with poor short- and long-term outcomes with nitinol stenting in the larger infrainguinal arteries. Background: Nitinol stents have proven to be useful and safe, but imperfect, tools for treating claudication and limb-threatening ischemia. Primary and secondary patency in superficial femoral artery (SFA) occlusions treated with nitinol stents are up to 80% at 1 year, but restenosis is between 40-50% at 2 years. The causes of SFA and popliteal restenosis remain unclear. Stent fracture has been implicated in some cases of restenosis, but this is clearly the minority. Chronic mechanical trauma to the arteries caused by native vessel-stent interaction, intensified by limb motion over time, appears to be a more plausible explanation. Methods: Presented here are 2 cases of restenosis apparently caused by acute and chronic trauma to the native vessel from interaction of the artery with the ends of relatively rigid nitinol stent systems. Results: The source of some future restenotic and occlusive events are not apparent using routine angiography techniques. Conclusion: The additional step of an on-table leg bend test at 80-90 degrees will allow the interventionalist to visualize many cases of negative interaction between the native artery and the stents that will occur during routine movement. This allows the operator to potentially avoid stent-induced arterial trauma. (J Invasive Cardiol 2005;17:482-486) Imaging Routine Visualization of the Left Internal Mammary Artery Before Bypass Surgery: Is It Necessary? Authors: Pragnesh Patel, Nicolas W. Shammas, Matthew J. Kapalis, Eric J. Dippel, Jon Lemke, Catherine Harb The left internal mammary (LIMA) is an ideal conduit for bypassing the left anterior descending artery (LAD) during coronary artery bypass surgery (CABG). In this study, we evaluate the frequency of significant disease in the LIMA prior to CABG and describe associated significant lateral costal branches (> 1.5 mm), subclavian disease and vertebral disease. In 115 consecutive patients referred to CABG, 101 patients met the inclusion criteria. All patients who underwent routine visualization of the LIMA. vessels were reviewed and quantitatively analyzed by an independent reader. Disease in the LIMA, left subclavian and vertebral arteries were graded and considered significant if lesions were > 50%. Lateral costal branches of the LIMA were also noted for their presence and size. Of the 101 patients, 87.1% of the LIMAs prior to surgery were without any disease. One LIMA had a 25-50% narrowing and the remaining LIMAs showed 0-25% disease. Of the LIMAs, 48.5% had lateral costal branches with diameters > 1.5 mm. The incidence of significant left vertebral disease and proximal subclavian disease was 37.6% and 5%, respectively. Cardiolite stress imaging post-CABG (n = 75) showed that when ischemia persisted in the anterior wall in patients with a LIMA to the LAD, this was not associated with the presence of significant LIMA disease, lateral costal branches, or subclavian disease identified pre-operatively. We conclude that the LIMA rarely shows significant disease on routine visualization prior to CABG. Asymptomatic subclavian artery disease and the presence of lateral costal branches pre-operatively did not correlate with post-CABG ischemia in the LAD territory. (J Invasive Cardiol 2005;17:479-481) Electrophysiology A Novel Radiation Protection Drape Reduces Radiation Exposure during Fluoroscopy-Guided Electrophysiology Procedures Authors: Joseph J. Germano, Gina Day, David Gregorious, Venkataraman Natarajan, Todd Cohen Objective: The purpose of this study was to evaluate a novel disposable lead-free radiation protection drape for decreasing radiation scatter during electrophysiology procedures. Background: In recent years, there has been an exponential increase in the number of electrophysiology (EP) procedures exposing patients, operators and laboratory staff to higher radiation doses. Methods: The RADPAD® was positioned slightly lateral to the incision site for pectoral device implants and superior to the femoral vein during electrophysiology studies. Each patient served as their own control and dosimetric measurements were obtained at the examiner's elbow and hand. Radiation badge readings for the operator were obtained three months prior to RADPAD use and three months after introduction. Results: Radiation dosimetry was obtained in twenty patients: 7 electrophysiology studies, 6 pacemakers, 5 catheter ablations, and 2 implantable cardioverter-defibrillators. Eleven women and nine men with a mean age of 63 ± 4 years had an average fluoroscopy time of 2.5 ± 0.42 minutes/case. Mean dosimetric measurements at the hand were reduced from 141.38 ± 24.67 to 48.63 ± 9.02 milliroentgen (mR)/hour using the protective drape (63% reduction; p Conclusion: The use of a novel radiation protection surgical drape can significantly reduce scatter radiation exposure to staff and operators during a variety of EP procedures. (J Invasive Cardiol 2005;17:469-472)