Ball, T., Foerst, J., & Vorpahl, M. (2010, May). Vascular insights into the treatment of acute myocardial infarction by post-mortem in situ microcomputed tomography and histology. European Heart Journal.
This study summarized a novel process of treatment for ventricular tachycardia in a 62 year old male patient with severe pancreatitis. After completely cardiac angiography, it was revealed that a arterial occlusion existed in the left anterior descending artery. After undergoing Thrombectomy, Two bare metal stents were implanted to ensure arterial integrity. One hour post operation the patient developed severe cardiac trauma and died. The cause of death was assumed to be a result of acute stent thrombosis resulting from calcification of the arterial wall.
Ball,, T., Foerst,, J., Vorpahl, M., Powell, R., Virmani, R., & Kaplan, A. (2010, August 2). Embolic Stroke after Carotid Stenting: Microscopic Computed Tomography Analysis of En Bloc Surgical Specimen Demonstrating Ulceration. Circulation.
This study analyzed the exact physiological factors involved in the development of carotid plaque, a major factor in the failure of stent devices as it causes ischemic strokes and on occasion propagation of the carotid bifurcation. Taking a 79 year old female patient as a model of device failure resulting from plaque development,it was revealed that severe calcification and several ulcers existed within the stent implant site. They exhibited signs of stent mitigation and in several areas, completely blocked strut interaction with the arterial wall, an important factor in the release of anti-inflammatory and anti-clotting agents. Overall, this study revealed a common case of plaque interference with device operation within an in-vivo environment, giving an example of which future can be based.
Foerst,, J., Ball, T., & Kaplan, A. (2010). Postmortem In Situ Micro-CT Evaluation of Coronary Stent Fracture. Catheterization and Cardiovascular Interventions.
This paper explained a new method used in the application of a non-invasive Micro-ct Scan. Using this new and improved method, researchers were able to better asses the cause of death of a 43 year old male who had undergone stent implantation. Allowing them to see more detailed images revealing several micro-fractures, the scan's increased precision enabled far better accuracy in terms of diagnosing the patients cause of death. The stent section (a compilation of two overlapping sirolimus stents) was then analyzed strut by strut through new methods of schematic representation, allowing researchers to better understand the various mechanical failures leading to the collapse of the stent.
Foerst, J., Ball, T., Vorpahl, M., Virmani, R., & Kaplan, A. (2010, August). Post-Mortem Micro Computed Tomography Evaluation of Very Late Stent Thrombosis. Journal of the American College of Cardiology.
This study followed the treatment of a 71 year old man with severe myocardial infarction. After Percutaneous intervention consisting of implantation of paclitaxel eluting stents in the left Main, Left anterior descending, diagonal, and circumflex and bare metal implantation in the marginal, the patient was maintained on a minimal dose of anti-clotting medication. After 2.5 years, the Patient encountered sudden death, resulting from acute stent thrombosis. A Biopsy later reported the existence of poor endothealization over the stent struts, explaining development of stent thrombosis through the continued development of arterial inflammation.
Farb, A., Weber, D. K., Kolodgie, F. D., Burke, A. P., & Virmani, R. (n.d.). Morphological Predictors of Restinosis After Coronary Stenting in Humans.
This study focused on the growth of neointimal (inside the stent) tissue after stent implantation. Correlating increased irritation of the arterial surface as a result of surgical implantation with such growth and in-stent restinosis, this project concluded that by decreasing damage (both penetration and irritation) to the surrounding tissue of a stent during insertion, the probability of in-stent restinosis could be reduced, eliminating a common clinical problem in today's field of cardiovascular interventional therapeutics.
Ino, Y., Toyoda, Y., Tanaka, A., Ishii, S., Kusuyama, Y., Kubo, T., . . . Akasaka, T. (n.d.). Predictors and Prognosis of Stent Fracture After Sirolimus-Eluting Stent Implantation.
Investigating the predictors and post-operative aspects of stent fracture, this study aimed to discover the causes and signs of in-stent restinosis. By evaluating 273 patients for biological and mechanical indicators, data was collected and analyzed for correlations in stent failure.
Karanian, J. W., Chiesa, O. A., Desai, P., Seward, K. P., Kreitz, M., Virmani, R., & Pritchard, W. F. (n.d.). Drug Retention in the Coronary and Femoral Arteries is Dependent on the Route of Administration in Swine: Assessment of Intimal and Adventitial Intro-Vascular and Systemic Pharmacokinetics and Toxicology with Nanopartical Albumin Bound-Paclitaxel.
This study reported the results of a experiment studying the effects of varying coronary delivery on nanoparticle retention, highlighting its effectiveness in adventitial delivery versus luminal and intimal pathways. This study then continued to suggest the application of the latter in determining the efficiency of delivering anti-restenotic drugs and the resulting pharmokinetic and toxicity profiles.
Karanian, J. W., Lopez, O., Rad, D., McDowell, B., Kreitz, M., Esparza, J., . . . Pritchard, W. F. (n.d.). Quantitative Mapping of Vascular Geometry for Implant Sites.
This study aimed to characterize the deformations and changes that occur in arterial vasculature as a result of changes in patient position. Applying novel geometric modeling devices and algorithms to identify changes in arterial vasculature, clinical trials were then completed to identify how certain deformations affect stent efficiency and structural integrity. Applying 3-D modeling systems to the data collected, this study concluded that further must be done to determine the affects of vascular change on stent action within a target vessel.
Karanian, J. W., PhD., Jaoudeh, N. A., MD., Glossop, N., PhD., Cleary, K., PhD., Chiesa, O. A., DVM, PhD., Dreher, M., PhD., . . . Wood, B. J., MD. (n.d.). Translational Technologies in EVAR: Multimodality Interventions. Endovascular Today.
Discussing the wide range of technologies available today in the fight against aortic disease, this article covers a wide a range of devices used in diagnosing and treating cardiovascular ailments. Discussing such scanning devices as EM tracking, ultrasound, fluoroscopy, and computed tomography, the ability of doctors to assess and intervene in cardiovascular deformations has increased and now includes a wide range of possibilities.
Pritchard, W. F., Kreitz, M., Lopez, O., Rad, D., McDowell, B., Nagaraja, S., . . . Karanian, J. W. (n.d.). The role of Imaging Tools in Biomedical Research: Preclinical Stent Implant Study.
In this study, the role of advanced imaging technology in stent implantations is discussed, following their individual roles in providing scans through which stents could be implanted. This study also assessed the ability of multi-modality approaches in diagnosing problems to insure the highest level of assurance and post-operative patient health. Highlighting the need for the use of clinical imaging devices in pre-clinical trials, this study emphasizes the need for more reliable data in the device development and evaluation process.
Mentorship References: 10-20
TL, P., & R, W. (2006, December 19). Clinical applications of optical coherence tomography. J Interv Cardiol.
This paper covered the various current clinical applications of Optical Coherence Tomography (OCT) and emphasized its role as a precise and highly accurate imaging device. Describing its use in the detection of atherosclerotic plaque, it is maintained that its resolution is a several magnitudes greater than that possible through the use of intravascular ultrasound, rendering it the best imaging modality currently available for in-vivo stent analysis. This study gave me a greater degree of insight into the current clinical applications of OCT technology and its position as the best scanning modality available.
E, R., G, V. S., N, B., A, C. A., RJ, C. G., Giessen, V. D., & PW, S. (2010, May 6). Optical coherence tomography in patients with acute coronary syndrome. EuroIntervention.
This study described the application of OCT scanning equitment in the analysis of vascular lesions in patients suffering from Acute Coronary Syndrome (ACS). This study developmed new data on the interaction of atheroscerotic plaque within ACS patients, especially in highliting the differnces found between patients suffering from acute myocardial infarction, versus those with stable angina. The application of OCT remained a crucial tool in further understanding ACS due to its immense detail. Overall, this study once again defined the role of OCT technology in providing high resolution in-vivo images for the use of research and experimentation.
JS, M., CS, N., E, Y., M, U., TJ, P., JC, G., & Phillips, H. R. (2009, December).
Preliminary observations using optical coherence tomography to assess neointimal coverage of a metal stent in a porcine model. Cardiovasc Revasc Med.
Late stent Thrombosis remains a potent problem in the long term survivability and treatment of patients suffering from vascular deformation. This study evaluated neointimal coverage within a porcine model through the use of OCT technology, procuring data on neointimal thickness and coverage of stent struts. Early neointimal coverage data was concluded to be accurate and on par with pathological correlations, testifying to the accuracy and practical use of OCT scanning modalities. This study could be applied in the future in helping to identify forms of inflammation that occur as a result of stent implantation and represent a experimental model off which future OCT testing could be based.
Guagliumi, G., Sirbu, V., Musumeci, G., Bezerra, H., Aprile, A., Fiocca, L., . . . Costa, M. (2010, August).Strut coverage and vessel wall response to a new-generation paclitaxel-eluting stent with an ultrathin biodegradable abluminal polymer: Optical Coherence Tomography Drug-Eluting Stent Investigation (OCTDESI). Circ Cardiovasc Interv.
Polymer based drug eluting stents have long been known to be a possible cause of delayed healing and loss of neointimal coverage, a important step in assuring vessel integrity and health. This study compared the effectiveness of abluminal coated stents versus a basic bare strut design in order to asess the polymers ability to inhibit restinosis. Using 60 patients as a data set, OCT scanning was used to collect neointimal and strut coverage data. It was found the the use of a polymer coating did not increase stent coverage and had no visible affect on vessel performance. This study’s analysis of the affects various stent combinations have on neointimal tissue thickness and vessel integrity reflects my goals to pursue correlations present between stent design and its resulting interaction with a vessel environment.
Murakami,, D., Takano,, M., Yamamoto,, M., Inami, S., Ohba,, T., Seino,, Y., & Mizuno,, K. (2009, September). Advanced Neointimal Growth is Not Associated With a Low Risk of In-Stent Thrombus. Cardiovascular Intervention, 73, 1627-1634.
This study covered research involving analysis of long term affects associated with sirolumus and paclitaxel eluting stents, specifically late stent thrombosis (LST) and incomplete endothelialization. OCT scanning was used in order to obtain stent strut images and measurements of neointimal thickness, a indicator of delayed endothelialization and LST. Through this, PES and SES stents were compared, analyzing for everything from tissue thickness and health, to occlusion measurments and thrombus detection.
Kim,, J.-S., Kim, J.-S., Kim, T. H., Fan, C., Lee, J. M., Ko, Y.-G., . . . Jang, Y. (2010, February). Comparison of Neointimal Coverage of Sirolimus-Eluting Stents and Paclitaxel-Eluting Stents Using Optical Coherence Tomography at 9 Months After Implantation. Circulation , 74.
This study strove to compare Sirolimus and Paclitaxel Eluting stents through the use of OCT imaging for neointimal coverage. Implanted for 9 months, these stents were analyzed thoroughly for endothelial coverage, demonstrated by a recent autopsy study to be the most powerful histological predictor of Late stent Thrombosis. Concluding that the rate of uncovered stents was negligible and that a longer study would be needed to obtain any definitive results, this project effectively applied the use of OCT imaging in the analysis of stent design and corresponding vessel interaction. Overal, this study represents a possible model upon whicha future study could be based and relates greatly to my current research on the importance of re-endothelilization in vessel recovery.
Shin, E.-S., Garcia, H., Okamura, T., Wykrzykowska, J., Gonzalo, N., Shen, Z., . . . Serruys, P. (2010, September 8). Comparison of Acute Vessel Wall Injury After Self-Expanding Stent and Conventional Balloon-Expandable Stent Implantation: A Study with Optical Coherence Tomography. J INVASIVE CARDIOL, 22(9), 435-439.
This study evaluated the affects of both self expanding and traditional Balloon-Expandable Stent Implantation techniques through the use of Optical Coherence Tomography to attain a greater degree of accuracy and precision. Two groups, representing both implantation methods, were utilized in order to minimize statistical deviation and attain a greater depth of understanding. It was concluded that Self-expanding stents exhibited a smaller degree of intrastent dissection than the traditional angioplasty method. This experiment only attests to the detail and precision with which OCT technology operates. In the future, experiments such as this will remain helpful in dissociating what implantation methods operate most effectively, as well as how to best implement OCT scanning within a research environment.
Agostoni, P., Van Belle, E., & Stella, P. (2010, September 8). Optical Coherence Tomography Assessment of a Coronary Bare Cobalt Chromium Stent Deformed by the Removal of an Entrapped “Jailed” Guidewire. J INVASIVE CARDIOL, 22(9), 453-455.
This study documents a procedure involving the removal of a deformed cobalt chromium stent’s guide wire. Treating a 64 year old patient with acute coronary syndrome with a occlusion in the first diagonal branch, a stent was implanted using traditional guide wire techniques. After becoming caught due to a deformation within the stent, attempted removal only resulted in the threat of complete arterial dissection. As a result, a separate micro catheter was used instead, leading to successful removal. The stent was later verified to be deformed through the use of OCT scanning equipment, but it was determined that the resulting inflammation did not cause flow-threatening stenosis, so medical treatment continued as normal. Overall, this study represents a excellent example of the application of OCT technology within a surgical environment, and serves as a excellent model upon which further research could be based.
T, O., JL, G.-C., PW, S., N, B., S, D. W., J, D., . . . E, R. (2010, August 6).
Reproducibility of coronary Fourier domain optical coherence tomography: quantitative analysis of in vivo stented coronary arteries using three different software packages. EuroIntervention.
This study employed the use of advanced Fourier Domain Optical Coherence Tomography in order to image longer vessel segments. Using high data acquisition rates and automated catheter retraction, various quantitative analysis algorithms were compared in order to find the best possible solution exhibiting reproducible and accurate in-vivo scans. Fourier domain OCT was found to produce excellent rates of reproducibility and precise in-vivo images. Overall, this study exhibits the wide range of OCT modalities available and could be applied in future investigations to assist in collecting the best possible results.
P, T., G, F., C, M.-A., N, K., P, B., E, P., . . . C, D. M. (2010, August). Simple versus complex approaches to treating coronary bifurcation lesions: direct assessment of stent strut apposition by optical coherence tomography. Rev Esp Cardiol.
This study analyzed the best possible approaches to treating lesions located within coronary bifurcations. Indicating that methods involving malapposition of stent struts lead to an increased risk of failure, the best possible method of treatment was discussed, from simple straightforward stent implantations to Culottes method. OCT scanning was used to asess the differing methods and their resulting degrees of stent malapposition, concluding that both exhibited almost identical results. This study could be applied in future experiments to assist in the determination of the most effective implantation technique when dealing with bifurcated vessel environments.
Kume, T., & Yoshida, K. (2005, November). Visualization of Neointima Formation by Optical Coherence Tomography. Int Heart.
Coletta, J., & Costa, M. A. (2008, October 31). Use of Optical Coherence
Tomography for Accurate Characterization of Atherosclerosis. Arq Bras
Bouma, B. E., & Jang, I.-K. (2003). Evaluation of intracoronary stenting by
intravascular optical coherence tomography. Heart.