Interventional Technologies Research Articles

Arterial remodeling after experimental percutaneous injury is highly dependent on adventitial injury and histopathology

Background: The extent and nature of unfavorable geometric remodeling, especially related to the adventitia, has not been studied previously. The purpose of this study was to examine two methods of experimental arterial injury, characterize the extent of remodeling, and determine if remodeling is injury-specific. Methods: Two methods for producing coronary stenoses in pigs were used: heat injury using thermal balloon angioplasty (resulting in adventitial fibrosis), and copper stent implantation (resulting in intense inflammation). Histomorphometric parameters included changes in neointimal thickness (delta neointima) from uninjured to injured sections, and differences in area circumscribed by the internal and external elastic laminas (delta internal elastic lamina area and delta external elastic lamina area, respectively). Remodeling was calculated for each lesion as the enlargement of the external elastic lamina area or internal elastic lamina area for incremental neointimal thickening, expressed as the slopes delta external elastic lamina area/delta neointima and delta internal elastic lamina area/delta neointima. Results: Remodeling indices for the heat lesions were negative (delta internal elastic lamina area/delta neointima=−0.15, delta external elastic lamina area/delta neointima=−0.64) and indicated little remodeling in contrast to copper stent injury (delta internal elastic lamina area/delta neointima=0.95, delta external elastic lamina area/delta neointima=1.20). Conclusions: Remodeling in fibrotic compared to inflammatory lesions differs markedly, and may explain increased restenosis rates observed in thermal balloon angioplasty in patients. This formulation may be useful to study remodeling and restenosis following other interventional technologies.

Reply

We appreciate the thoughtful letter from Dr. Kügler in response to our cautions about the potential role of P300 testing in the treatment of vascular dementias. Clearly Dr. Kügler is just the type of careful researcher and worker who will be able to shepherd a technology such as the P300 into clinical practice when its “clinical utility… prove(s) useful in defining high-risk patients, evaluating their clinical course, and in targeting preventive and therapeutic measures.” We are especially pleased that he sees the role of the P300 in terms of careful control of risk factors. These are exciting times for those involved in the treatment of neurological disease because both dramatic advances in neuropathological understanding and interventional technologies are rapidly making their way from the laboratory into the clinical setting. All of us involved in driving this revolution must be dedicated to providing the clinician with the tools necessary to safely and reliably determine the best diagnostic and treatment options for each patient. Dr. Kügler and his coworkers are clearly dedicated to reaching for this holy grail and we look forward with anticipation to a future that includes the P300.

New Interventional Technology

New Interventional Technology

760-1 The Precision Guided Directional Laser Atherectomy Catheter: A New Approach to Percutaneous Coronary Revascularisation

Directional coronary atherectomy has been shown to be a successful method of percutaneous coronary revascularisation, particularly in large vessels with eccentric stenoses. The application of laser technology to coronary revascularisation has not been as successful, mainly because of a relatively high rate of vessel wall perforation. We describe a combination endovascular imaging/laser atherectomy catheter (Precision Guided Directional Laser Atherectomy Catheter, PGDLAC) that may overcome these shortcomings by allowing precision guided intervention. The catheter consists of a laser cutting device with an integrated imaging system (fiberoptic or ultrasound). Fiberoptic imaging allows exact positioning and orientation of the laser tipped catheter within the vessel lumen, and visual control of plaque excision. In the second step, the vessel wall morphology is demonstrated using ultrasound, and the result of the intervention assessed without removing the catheter. Excised plaque fragments are extracted by way of the catheter, Preliminary results of in vitro experimental application of this device in human coronary arteries is promising and confirms the technical feasibility. Such a device potentially offers the advantages of effective, precision guided atherectomy in plaques of variable constitution, with a potential reduction in procedure time and radiation dose. By combining state of the art imaging and interventional technology, we have developed a precision guided directional laser atherectomy system that may provide more effective percutaneous coronary revascularisation than previously developed techniques.

Cardiovascular - Interventional Technology Exam ReviewCardiovascular - Interventional Technology Exam Review, by Richard R. Carlton and Deborah Philpot. J. B. Lippincott Company. 1992. US $15.95. ISBN: 0-397-54945-8

Book ReviewCardiovascular - Interventional Technology Exam Review Mohd R. ArafahFRCP(C), FACP, FACC Mohd R. Arafah Search for more papers by this author Published Online:1 Jul 1994https://doi.org/10.5144/0256-4947.1994.355aSectionsPDF ToolsAdd to favoritesDownload citationTrack citations ShareShare onFacebookTwitterLinked InRedditEmail AboutIntroductionThe book contained 500 multiple choice questions with 3 full length simulated exams and provided explanation for each answer. As well, it has full references for further study and 5 reference tables in appendix.The book has been written by an experienced team who has been involved in interventional procedures over one decade. It is directed mainly to junior fellows and nurses who are involved in these interventional procedures.To prepare for an exam like the one held by the American Registry of Radiologic Technologists, it is advisable to read over a textbook and then try to go over such exam review.The book is easy to review anytime. The questions tend to be practical and of clinical significance. A few points have been mentioned which one cannot learn from any textbook but only from being in the laboratory doing procedures.I think it will be a very useful review book to have in each technician’s library. Previous article FiguresReferencesRelatedDetails Volume 14, Issue 4July-August 1994 Metrics History Published online1 July 1994 InformationCopyright © 1994, Annals of Saudi MedicineThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.PDF download

Clinical success, complications and restenosis rates with excimer laser coronary angioplasty

The role of excimer laser angioplasty in treating complex coronary artery disease remains uncertain. A randomized trial comparing this new technology with balloon angioplasty cannot be designed until systematic analysis identifies the lesion types that are likely to benefit from treatment with excimer laser angioplasty. In a cohort of 764 patients who had 858 coronary stenoses treated with excimer laser-facilitated angioplasty, relative risk analysis was used to examine acute success, complications and restenosis rates, and the results were compared with those of balloon angioplasty to identify the lesion types that show the greatest benefit with the new treatment. Clinical success was achieved in 657 patients (86%), as indicated by ≤50% residual stenosis and no in-hospital complication. A major in-hospital complication (death, bypass surgery, or Q-wave or non-Q-wave myocardial infarction) occurred in 58 patients (7.6%). Follow-up angiography was obtained in 70% of eligible patients. Combining angiographic and noninvasive restenosis rates yielded an overall restenosis rate of 46%. Relative risk analysis showed that major complications occurred frequently in lesions at an arterial bifurcation (odds ratio [OR] 5.96 [2.76, 12.6]; p = 0.001). However, certain complex lesions that are difficult to treat with balloon angioplasty (saphenous vein graft lesions, lesions >10 mm, ostial lesions, calcified stenoses, total occlusions and unsuccessful balloon dilatations), analyzed together as a group, had lower complication rates by univariate (OR 0.59 [0.35, 1.00]; p = 0.051) and multivariate logistic regression (p = 0.006) analyses. Restenosis rates were higher for lesions >10 mm in length (OR 1.28 [1.02, 2.29]; p = 0.014) and for those treated with laser alone (OR 1.69 [1.02, 2.88]; p = 0.049). In conclusion, the use of excimer laser-facilitated angioplasty to treat many lesion types will be limited by significant restenosis, despite acceptable initial clinical results. Favorable success rates with this new technology were found for a group of 6 lesions that comprise the “alpha class” (saphenous vein graft lesions, long lesions, ostial lesions, calcified stenoses, total occlusions and unsuccessful balloon dilatations). Direct, controlled comparison with other interventional technologies will define the ultimate role of the excimer laser angioplasty procedure.

Intracoronary ultrasound evaluation of interventional technologies

The feasibility and applicability of intravascular ultrasound (IVUS) of the coronary arteries were evaluated in 65 patients undergoing 70 coronary interventional procedures. Morphologic and quantitative analyses were performed with a mechanically rotated IVUS catheter (4.8Fr, 20 MHz) and with orthogonal view cineangiography. A semiautomated edge-detection algorithm was used for cineangiographic quantification. Coronary interventions included 45 percutaneous transluminal coronary angioplasties, 9 excimer lasers, 11 directional coronary atherectomies, 3 rotational atherectomies and 2 stents. Most lesions consisted of a mixture of plaque composition (hard, n = 30; soft, n = 64). Other unique morphologic data by IVUS were plaque topography (eccentric, n = 34; concentric, n = 36) and vessel dissection (IVUS [n = 29] versus angiography [n = 14], p < 0.05). Postprocedure minimal lumen diameter and cross-sectional area measured by IVUS were larger and poorly correlated with angiography (r = 0.28, standard error of the estimate = 0.52 mm; r = 0.08, standard error of the estimate = 1.0 cm 2, respectively). IVUS is more sensitive than angiography when assessing postintervention lesion characteristics including vessel dissection and plaque morphology. Catheter-based ultrasound appears to be a useful adjunct to contrast angiography when evaluating and comparing the therapeutic impact of conventional percutaneous transluminal coronary angioplasty with new technologies.

Interventional Cardiology Techniques for Coronary Artery Disease

This review updates and extends observations made in this journal in March 1988. The focus then was on percutaneous transluminal coronary angioplasty and the clinical results of its practical application. A concern was expressed that science lagged in solving the major problems of rethrombosis and restenosis. The NHLBI Bypass Angioplasty Revascularization Investigation (BARI) study was still in the planning phase. In 1991, the scene has changed. Interventional cardiology now embraces a multitude of different catheter devices--angioplasty, atherectomy, laser, stents. Basic scientists are increasingly involved in addressing the restenosis issue. Our national heart meetings are increasingly oriented towards molecular biology approaches to solving the remaining problems. The BARI trial has nearly completed patient entry, and we eagerly await its results. The cardiologist and surgeon are faced with increasingly complex decisions with respect to interventional technologies, involving not only whether to use them, but which ones.

Importance of the Functional Integrity of the Endothelium in Coronary Vasomotion in Humans

Although our understanding of endothelial functon has been substantially expanded by numerous experimental studies since the discovery of endothelium-derived relaxing factor (EDRF), the functional significance of endothelial function in humans, in particular in the coronary circulation, remained elusive. Recently, the application of new interventional catheter technology and accurate quantitative coronary angiogrphy has set the stage for evaluating the potential importance of the endothelium of coronary arteries in humans.

Importance of the Functional Integrity of the Endothelium in Coronary Vasomotion in Humans

Summary: Although our understanding of endothelial function has been substantially expanded by numerous experimental studies since the discovery of endothelium-derived relaxing factor (EDRF), the functional significance of endothelial function in humans, in particular in the coronary circulation, remained elusive. Recently, the application of new interventional catheter technology and accurate quantitative coronary angiography has set the stage for evaluating the potential functional importance of the endothelium of coronary arteries in humans. Intracoronary application of acetylcholine has been shown to provide a useful tool for identifying coronary endothelial dysfunction, i.e., modest coronary vasodilatation in normal subjects but paradoxical vasoconstriction in atherosclerosis. Sympathetic stimulation by cold pressor test exactly mirrors the response to acetylcholine in normal and atherosclerotic coronary arteries but not in hypercholesterolemia. Flow-dependent dilation can be demonstrated in human coronary arteries in vivo and may play a modulatory role in coronary vasomotor tone; however, this dilation in response to increased flow is impaired in angiographically visible atherosclerosis. By measuring the blood flow response to acetylcholine (and papaverine as a nonspecific dilator), the endothelial function of the coronary microvasculature can be assessed, demonstrating that endothelial function of the coronary microvas-culature is substantially depressed in hypercholesterolemia. This may impair coronary perfusion and could facilitate platelet aggregation in the microcirculation. Thus, evaluation of endothelial function provides a useful tool for identification of early functional vascular abnormalities (both of epicardial coronary arteries and the microcirculation) at a stage not detectable by coronary angiography. This should allow the elucidation of therapeutic interventions that are able to prevent the progression of atherosclerosis at an early stage rather than late, when the efficacy of such a treatment appears to be limited.

New interventional technology for the management of multivessel coronary artery disease

New interventional technology for the management of multivessel coronary artery disease

Comment on the Clinical Appropriateness of an Emerging Technology

HomeRadiologyVol. 172, No. 3 PreviousNext 25th Anniversary of Transluminal AngioplastyEditorialsComment on the Clinical Appropriateness of an Emerging TechnologyGordon K. McLean, Dana R. Burke, David L. MarinelliGordon K. McLean, Dana R. Burke, David L. MarinelliAuthor AffiliationsAddress reprint requests to G.K.M.Gordon K. McLeanDana R. BurkeDavid L. MarinelliPublished Online:Sep 1 1989https://doi.org/10.1148/172.3.941MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Article HistoryReceived: May 22 1989Accepted: May 24 1989Published in print: Sept 1989 FiguresReferencesRelatedDetailsCited ByJournal of Vascular and Interventional Radiology, Vol. 14, No. 9Journal of Vascular and Interventional Radiology, Vol. 8, No. 1General Principles for Evaluation of New Interventional Technologies and DevicesJournal of Vascular and Interventional Radiology, Vol. 8, No. 1Catheterization and Cardiovascular Diagnosis, Vol. 27, No. 1Emergency Medicine Clinics of North America, Vol. 10, No. 1Review of Laser Assisted AngioplastyAustralasian Radiology, Vol. 35, No. 2Journal of Vascular and Interventional Radiology, Vol. 2, No. 4, Vol. 7Lasers in Medical Science, Vol. 5, No. 3Journal of Vascular and Interventional Radiology, Vol. 1, No. 1Recommended Articles RSNA Education Exhibits RSNA Case Collection Vol. 172, No. 3 Metrics Altmetric Score PDF download

Strategies for developing innovative programs in international medical education. Identification of educational needs

A U.S. medical educator noted that the needs of developing countries are not necessarily addressed by traditional methods of medical education in the United States, involving high-technology education, technology transfer, development of academic personnel, and the like. In many developing nations, where there may be a surplus of doctors and many unemployed doctors, there is also a vast population of underserved people. Many of the physicians may have been trained inappropriately, or they were not comfortable in certain environments. In order to have an impact on the vast population, that kind of anachronism must be addressed. He inquired whether there is a role for the United States in addressing the health of communities rather than the sickness of individuals. It was observed that the health needs of developing countries are often thought to relate to the issues of hygiene, sanitation, and prevention and that these needs are homogeneous. The needs for interventional technology and preventive primary care should be differentiated, and the requirements at both levels of assistance should be heeded, be it at a primary and preventive level or at the level of specialist-oriented technological intervention. There was discussion about the dichotomy that exists between schools of public health in the United States and the medical schools with which they are associated. They were referred to as "two separate cultures." Thus, some suggested that U.S. physicians involved in curative medicine need to be exposed to community-based medicine in other countries, and many questioned whether other countries should seek to model their systems after those in the United States.(ABSTRACT TRUNCATED AT 250 WORDS)

Congenital arteriovenous malformation of the female pelvis: A gynecologic perspective

Nine female patients with the rare congenital arteriovenous malformation of the pelvis were treated at New York University Medical Center in the past 8 years. The patients varied significantly in the anatomic location of the arteriovenous malformation, clinical presentation, and natural course of disease. A gynecologic perspective on the management of this condition is presented, which ranges from a conservative approach with preservation of childbearing potential to extensive pelvic surgery. The important role of modern interventional radiology technology and the multidisciplinary approach are stressed. The unpredictable course of disease after any intervention should be emphasized in planning the management of pelvic arteriovenous malformation.

New interventional technology

New interventional technology

Mousetraps, Developmental Research, and Social Work Education

As inquiry directed toward the development of interventional and other social technology for social work, developmental research involves those methods by which interventional innovations and other aspects of social technology are analyzed, designed, created, and evaluated. Interventional innovation in developmental research is a very different paradigm from the more familiar behavioral science model of research oriented toward knowledge building. The purposes and outcomes of inquiry and the phases, operations, methods, and sources of data of developmental research are highlighted by contrasting this new model of research with more conventional methods. The introduction of developmental research into social work increases the number of available research methods and promises to strengthen its technical capability to accomplish its objectives. Developmental research may be the single most appropriate model of research for social work; this and other implications for graduate education in social work are di...