Biomedical subjects
E B Diethrich
Publications and source records attributed to E B Diethrich.
Endovascular techniques in adult aortic coarctation: the use of stents for native and recurrent coarctation repair.
PURPOSE: To report initial experiences with stent implantation in the treatment of native and recurrent aortic coarctation in adults. METHODS: Two adult patients were diagnosed with aortic coarctation: in one, the native aorta was involved, and in the other, the stenosis involved a prior coarctation repair. Both patients were offered and selected angioplasty with possible stent implantation as an alternative to surgery. RESULTS: In the patient with recurrent narrowing, thrombolysis and balloon dilation preceded the successful deployment of three Palmaz stents along the grafted segment. In the case of native disease, one Palmaz stent was implanted primarily at the site of a critical, focal stenosis. No complications were encountered, and recovery was uneventful. Follow-up at 12 and 6 months, respectively, showed sustained clinical improvement with resolution of symptoms and excellent hemodynamic values. CONCLUSIONS: The positive outcome in these early cases supports further evaluation of the efficacy of adjunctive or primary stenting for treatment of native or recurrent aortic coarctation in adults.
Endoluminal grafting for aneurysmal and occlusive disease in the superficial femoral artery: early experience.
PURPOSE: To examine whether endoluminal grafts (ELGs) of radically expandable polytetrafluoroethylene (PTFE) can successfully form durable internal conduits to revascularize lengthy occlusive disease and exclude aneurysms in the femoropopliteal (FP) arteries. METHODS: Under protocol, implantation of an unpredilated PTFE tube ELG anchored with Palmaz stents using a low-profile percutaneous delivery system was attempted in 50 symptomatic patients for a variety of pathologies: (1) restenosis; (2) complex lesions unlikely to be treated successfully with other endoluminal therapies; (3) acute angioplasty failure; and (4) aneurysms. There were 37 occlusions, 14 stenoses, and 2 long, combined stenotic-aneurysmal lesions in 47 native arteries, 5 FP grafts, and 1 femorotibial (FT) vein graft. Thirty-two percent of the patients had < or = vessel runoff. The average lesion length was 20.4 +/- 11.4 cm (range 1.5 to 40), and the mean preoperative ankle-brachial index (ABI) at rest was 0.53 +/- 0.14. RESULTS: In a 20-month period through April 1995, 50 patients (34 males, 16 females; mean age 69.5 years, range 45 to 87) underwent 54 procedures in 53 limbs; 55 ELGs were successfully deployed in 51 limbs; 2 patients were converted to FP bypass owing to technical problems (96% procedural success). There were 18 inhospital complications: 1 distal wire dissection repaired with an additional ELG; 2 hematomas requiring surgical repair; 1 graft collapse; 1 pseudoaneurysm at the site of a mid-ELG leak; 7 minor access sequelae; and 6 acute ELG thromboses, 4 treated with lytic therapy and balloon dilation, 1 with open thrombectomy, and 1 with bypass grafting. The mean postoperative ABI was 1.01 +/- 0.10. During the 30-day postprocedure period, 2 ELGs rethrombosed and 2 other limbs (3 ELGs) occluded; 1 thrombosis and 1 rethrombosis were lysed successfully, but the other 2 patients had an FP bypass. Over the mean 8.3 +/- 5.5 month follow-up, 6 additional ELGs occluded and 1 reoccluded; 4 were successfully treated by endovascular techniques for a primary patency of 72% and secondary patency of 84% by life-table analysis. CONCLUSIONS: Endovascular grafting is a conceptually attractive technique that has the potential to expand the current boundaries of interventional treatment. This preliminary experience attests to the feasibility and safety of ELG deployment in the superficial femoral arteries. Whether such a device can match the durability of classical revascularization techniques remains to be determined in clinical trials when device configurations and deployment techniques have been standardized.
Angioscopic evaluation of an endoluminal aortic graft: the first clinical experience.
PURPOSE: Balloon aortoscopy has been described for viewing aortic endoluminal anatomy and guiding aortic stent placement in animals. We report the first clinical use of this technique to visually inspect the proximal portion of a 1-year-old endovascular aortic graft, its proximal fixation stent, and its relationship to the renal arteries. METHODS: The aortoscope is a modified fiber-optic endoscope that is fitted over the lens with a transparent, saline-filled balloon for blood displacement. Its performance was evaluated in a 62-year-old woman who had a Parodi-type Dacron/modified Palmaz stent endoluminal graft implanted to exclude an infrarenal aortic aneurysm in 1994. One year later, during an angioplasty procedure for symptomatic left subclavian and left common iliac artery stenoses, the 1-year-old endoluminal graft was inspected with the balloon-tipped angioscopic assembly. RESULTS: Introduced via the left brachial artery, the aortoscope provided a panoramic view of the endoluminal surface through the solution-filled balloon. The endoluminal aortic graft was clearly identified, as were both renal artery orifices proximal to the graft. The surface of the proximal stent was smooth and without exposed metal. No complications occurred with the angioscopy technique. CONCLUSIONS: Aortic angioscopy can be used to evaluate endoluminal aortic grafts and endoluminal anatomy. It provides clear, magnified views that may be useful for guiding precise placement and assessing the function and healing of endoluminal devices in the aorta.
Polymeric covers and coats for metallic stents: microporous PTFE and the inhibition of intimal hyperplasia.
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The clinical value of three-dimensional intravascular ultrasound imaging.
Two-dimensional (2D) intravascular ultrasound (IVUS) imaging can now be reconstructed into three dimensions from serial 2D images captured following a "pullback" of the IVUS catheter through the target site. Three-dimensional (3D) reconstructions provide "longitudinal" and "volume" images. The former is similar to an angiogram and can be examined in three dimensions by rotating the image around its longitudinal axis, providing clinically useful information during endovascular procedures. The volume view takes longer to create and is not an exact reconstruction, but it provides images that can be rotated into any spatial position. It visualizes the luminal aspect of the vessel particularly well. The clinical value of 3D IVUS is in the diagnosis of vascular disease and the assessment of endovascular interventions. Three-dimensional IVUS, which provides better, more informative images than 2D IVUS, can be particularly useful intraprocedurally in detecting inaccurate deployment of intravascular stents and endoluminal grafts.
Classical and endovascular surgery: indications and outcomes.
For more than 40 years, endarterectomy and bypass grafting have been the primary means of surgically revascularizing peripheral vessels threatened by atherosclerotic disease. However, with today's endovascular technology, stenoses and occlusions in nearly every circulatory system can be approached intraluminally with a wide variety of techniques: thrombolysis, laser angioplasty, atherectomy, balloon dilation, and intravascular stents. Just as exciting is the newer technique of endoluminal grafting, which has extended percutaneous therapy to aneurysmal disease in the thoracic and abdominal aorta and distal arteries, as well as to long-segment occlusive disease. Today's vascular surgeon is in a unique position to combine his or her classical surgical training with these catheter-based interventions. Certainly, the potential advantages of percutaneous therapy as compared to surgical reconstruction are significant: no general anesthesia or lengthy incisions, shorter hospitalization, lower morbidity and mortality, earlier intervention in the course of the disease, and less complicated reapplication in the event of disease recurrence. Undoubtedly, endovascular techniques will become a major component of the vascular surgeon's armamentarium, and as we approach the year 2000, they will be the treatment of choice in nearly every vascular pathology and circulatory system.
The sternal saw: a historical note with a modern message.
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Preliminary observations on the use of the Palmaz stent in the distal portion of the abdominal aorta.
The opportunities to avoid surgical treatment of distal abdominal aortic occlusive disease are expanding because of the proliferation in catheter-based techniques. Since January 1990, 24 symptomatic patients with distal abdominal disorders have been treated percutaneously with balloon angioplasty and intraluminal stenting. A total of 38 Palmaz stents were deployed at distal abdominal aortic sites; 21 additional iliac stents were implanted. After the procedure all patients improved clinically, and 83% (21/24) improved by objective measurement (average ABI 0.93 +/- 0.21). Three access-related complications occurred (two hematomas, one thrombus), but no complications were related to the stents. At up to 29 months of follow-up (average 10.3 +/- 6.7 months), clinical improvement persists in all patients (average ABI 0.93 +/- 0.22). In 11 patients eligible for follow-up aortography, all aortic stents are patent without evidence of restenosis. With the low likelihood for restenosis in the abdominal aorta, the long-term outcome of aortic stenting looks promising and may equal or surpass that found in the iliac region.
Regarding "Endovascular surgery credentialing and training for vascular surgery".
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Endovascular treatment of abdominal aortic occlusive disease: the impact of stents and intravascular ultrasound imaging.
Distal abdominal aortic occlusive disease has been conventionally treated with endarterectomy or bypass grafting. However, today's expanding spectrum of intraluminal devices and techniques may well replace classical surgery in this arterial region in all but a few instances. Since January 1990, we have investigated the potential for such endovascular therapies as thrombolysis, balloon dilation and intravascular stenting in 29 symptomatic patients with a variety of distal abdominal aortic pathologies. The prudent application of these intraluminal therapies hinges on accurate intra-arterial assessment. Arteriographic data are notably inadequate for most endovascular procedures; however, intravascular ultrasound imaging (IVUS) is a newer diagnostic tool that works particularly well in the aortoiliac region where angioscopy is more difficult to utilize for assessment. Using IVUS as a complement to arteriography, we were able to assess the need for 43 Palmaz stents in these cases of distal abdominal aortic pathologies; 23 additional iliac stents were deemed necessary. Moreover, IVUS was the only tool available to confirm adequate stent deployment. Given the apparent long-term success of stents in large-bore arteries, abdominal aortic stenting may ensure proximal inflow to distal vessels, saving many patients from an intra-abdominal operation. The specific intraluminal and transmural data offered by IVUS facilitates stent application and documents adequate deployment, two vitally important elements in the percutaneous treatment of abdominal aortic occlusive disease.
The treatment of aortic stenosis: is valvuloplasty ever an alternative to surgery?
The desire to extend the principle of balloon angioplasty to cardiac valve disease is understandable and commendable. Aortic valvuloplasty is associated, however, with an excessive complication rate, as reported by the Mansfield Scientific Aortic Valvuloplasty Registry (20.5% overall, including a 4.9% death rate within 24 hours and an additional 2.6% rate within 7 days for a 7.5% 1-week mortality). In contrast, the operative mortality for aortic valve replacement now ranges from 3%-5%, with perioperative complications far less than the one in five associated with valvuloplasty. Even if the two procedures had equivalent morbidity and mortality rates, the high incidence of restenosis (30%-60% range at 6 months) for the balloon technique precludes its widespread use for aortic stenosis. Despite the poor mid- and long-term results for balloon valvuloplasty, the procedure may have limited application in some clinical situations. Indeed, there are patients with concomitant systemic illnesses or advanced age ( greater than 80 years) who would not be good surgical candidates. In particular, valvular balloon dilation may be useful in bridging a seriously ill patient to a condition more favorable for replacement therapy. With few exceptions, however, valve replacement remains the gold standard for treatment of adult aortic stenosis.
Intravascular ultrasound imaging: an essential component of angioplasty assessment and vascular stent deployment.
Potential early complications of balloon angioplasty include occlusion due to vessel wall recoil, medial dissection, creation of intimal flaps, spasm and luminal thrombosis. These features have also been implicated in the development of restenosis and late occlusion. As a possible solution to these problems, an endovascular scaffold (stent) was proposed by Dotter in the 1960s, and initial studies suggested that use of such a device in specific circumstances may reduce complications related to major dissection, vessel recoil and spams. This paper reports the utility of two- and three-dimensional intravascular ultrasound (IVUS) imaging in assessing arterial morphology following balloon angioplasty, and guiding the need for, and adequacy of deployment of intravascular stents. IVUS imaging provides a technique to accurately assess the immediate results of angioplasty and examine both the luminal size and contour following intervention. Accurate imaging such as this is essential for the successful use of balloon expandable stents, by ensuring correct initial positioning and complete deployment at the time of balloon expansion. Two cases are reported which highlight the important issues which are critical to the ongoing development of endovascular therapies: (i) accurate assessment of the angioplasty results, and (ii) selection and confirmation of stent deployment. We conclude that IVUS imaging may provide a new standard for the assessment of angioplasty procedures and will play a pivotal role in identifying failure mechanisms of endovascular interventions.
Endovascular techniques for abdominal aortic occlusions.
The application of endovascular interventions is spreading to encompass more anatomic locations and a wider array of vascular pathologies. The combination of thrombolysis with intraluminal devices has been an important factor in applying interventional therapy to abdominal aortic occlusive disease, where such intraluminal options can reduce the need for abdominal surgery. Seven patients with total abdominal aortic occlusions were treated with antegrade, high-dose urokinase infusion delivered to the clot site over a 20-48 hour period prior to balloon dilation and Palmaz stent implantation for unresolved pressure gradients, residual plaque, lesion recoil, or dissection. Lytic therapy cleared the thrombus totally in 6 patients and sufficiently in the 7th to facilitate retrograde iliac artery wire passage. All 7 patients required stent implantation to maximize revascularization (11 stents deployed in the abdominal aorta and 10 in the common iliac arteries). There were 2 instances of post-procedural distal embolization attributable to the thrombolysis, but both were treated satisfactorily. In up to 28 months of follow-up, all patients remain asymptomatic. Combining lytic therapy and stenting extends the applicability of endovascular interventions to patients with aortic occlusion.
Migrated Kimray-Greenfield filter lodged in the right ventricle: surgical removal and transatrial reinsertion.
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Preliminary results of intraoperative excimer laser angioplasty: phase 1: an adjunct to coronary artery bypass surgery.
The excimer laser underwent phase I clinical trials at three centers to determine its safety for intraoperative coronary laser angioplasty as an adjunct to coronary artery bypass grafting. A 308-nm Xenon-Chloride, pulsed-wave excimer laser was used to perform angioplasty in 30 patients undergoing coronary artery bypass surgery. Forty vessels (30 patients) were treated, in which the extent of occlusion ranged from 30% to 100%, with complete occlusion in 40% of all vessels. Improvement in vessel luminal caliber was achieved in 33 (79%) vessels, with perforations occurring in 4 (12%) vessels, 2 of which required surgical repair. The lumens of the remaining 8 (19%) vessels were not enlarged, and 2 (5%) of these vessels were perforated. Luminal enlargement was most often achieved in totalled occluded vessels in which 16/17 (94%) were recanalized. No patients died within 30 days postoperatively. Five patients demonstrated biochemical and electrocardiographic evidence of myocardial injury 48 hr postoperatively, and one patient died of cardiac arrest 139 days postoperatively. On the basis of these results, we believe that excimer laser angioplasty can be performed safely to improve coronary luminal patency, even in totally occluded vessels, in an operative setting. The long-term value of this procedure remains to be elucidated.
Angioscopy in endovascular surgery: recent technical advances to enhance intervention selection and failure analysis.
Recent technical and procedural modifications have greatly enhanced the usefulness of angioscopy during angioplasty. A pulsed irrigation system, proximal and distal blood flow control by pressure, and attention to sheath/vessel diameter ratio were incorporated into a study in which angioscopy was used for pretreatment assessment in 23 patients with symptomatic peripheral vascular disease presenting for initial (8 patients) evaluation or repeat treatment (15 patients) following a previous vascular procedure. Twenty-five lesions were examined with a 2.3 mm flexible angioscope equipped with an irrigating lumen; there were no complications attributable to angioscopy. The angioscope was useful in the characterization of lesions for selection of the recanalization technique. Lesions more amenable to initial atherectomy were visualized in 12 patients; 7 occlusions were successfully treated with laser/balloon angioplasty, with angioscopy assisting in probe and/or wire passage in 4 cases. Three late reocclusions were identified angioscopically as due solely to thrombosis, indicating the need for thrombolytic therapy. Angioscopy also identified 4 cases of incomplete recanalization despite a satisfactory arteriographic image. Angioscopy was also used to evaluate stenotic lesions unaccompanied by thrombus formation in patients previously treated with laser-assisted angioplasty. Histologic evaluation of the biopsied plaques identified intimal hyperplasia as the etiology, matching identically similar specimens harvested from a lesion treated with balloon dilation only.
A double balloon occlusion technique for embolectomy in the trifurcation vessels.
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