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Biomedical subjects

E B Diethrich

Publications and source records attributed to E B Diethrich.

At least 55 records · Page 3Linked to original sources
PubMed1997

Stenting for abdominal aortic occlusive disease. Long-term results.

We report the long-term results of abdominal aortic stenting in 24 patients who underwent stenting for atherosclerotic occlusive disease (16 stenoses, 6 occlusions, and 2 ulcerative plaques). The occlusions were treated initially with thrombolytic therapy, and all lesions were balloon dilated. Indications for stenting were: residual gradient (n = 10); recoil (n = 7); dissection (n = 2); and atherosclerotic debris (n = 5). Thirty-eight Palmaz stents were implanted in the aorta, and 21 were implanted in the common iliac (n = 19) and external iliac (n = 2) arteries. Technical and clinical success was 100%. Over a mean follow-up period of 48 months (range, 1 to 67 months), 2 patients died and 2 were lost to follow-up. Two patients developed symptoms referable to the aorta (at 43 and 67 months), and each was managed successfully via an endovascular approach. There was no in-stent restenosis. Life-table analysis showed a 100% cumulative primary patency at 5 years. We conclude that stenting for abdominal aortic occlusive disease appears to offer long-term patency slightly superior to that of classical surgical intervention. Aortic stents also do not appear to be subject to restenosis. Follow-up in a larger patient cohort is needed to confirm these observations.

Aged↗
PubMed1997

Stenting for occlusion of the subclavian arteries. Technical aspects and follow-up results.

We report the results of stenting in 17 patients who underwent treatment for total occlusions in the subclavian arteries between July 1991 and December 1995. Fourteen of the lesions were located in the left side; 15 patients had a subclavian steal syndrome. The indications for treatment were vertebrobasilar insufficiency (n = 7); arm claudication (n = 5); vertebrobasilar insufficiency and upper-limb ischemia (n = 3); protection of a left internal mammary artery coronary bypass (n = 1); and an isolated subclavian steal syndrome (n = 1). A total of 23 stents were implanted in 17 patients; in 1 patient, 2 stents migrated during deployment, resulting in a 94% procedural success rate. One case of axillary thrombosis was successfully treated with local thrombolysis and balloon angioplasty. There were no postprocedural neurologic complications or deaths. Follow-up over a mean duration of 19.4 months (range, 4 to 56 months) revealed 1 asymptomatic restenosis at 5 months in a patient with 3 stents. Life-table analysis showed an 81% cumulative patency rate at 6 months. We conclude that stenting for occlusion of the subclavian arteries appears feasible and safe; however, further evaluation in a larger group of patients is needed to confirm these results.

Adult↗
PubMed1997

What do we need to know to achieve durable endoluminal abdominal aortic aneurysm repair?

The exclusion of abdominal aortic aneurysms with endoluminal grafts is in its earliest stages, and the technology is in continuous transition. While results with 1st-generation devices have been somewhat discouraging in some cases, lessons learned from these initial attempts have led to considerable improvement in device design and deployment techniques. Lower-profile devices that are smaller and more flexible have made implantation less traumatic, and the incidence of endoleak formation has been reduced to 10% or less in some series. A modified percutaneous approach has also been introduced, and it may reduce the need for open exposure of the femoral artery in endoluminal graft procedures. Treating aneurysm expansion earlier, perhaps at 4 cm, may allow use of simpler, straight-tube prostheses and prevent problems associated with the use of larger, bifurcated endoluminal grafts. Numerous endoluminal graft designs are being tested, including both internally and externally covered prostheses. The success with a covered device may depend upon the type of material used and the extent to which it covers the endoluminal graft; fabric covering over a completely metal structure may allow a high degree of perioperative success and improvement in late outcome. The use of "hooks" to anchor or stabilize the endoluminal graft is also under study but is still controversial. The expense associated with endoluminal graft technology is currently high; therefore, it is likely that cost savings will be the result of shorter hospitalizations, little or no time spent in the intensive care unit, and fewer pre- and postoperative tests.

Angiography↗
PubMed1997

Endoluminal grafting in the treatment of iliac and superficial femoral artery disease.

Treatment of iliac artery disease with stents has been generally successful; however, disease in the smaller arteries below the inguinal ligament has been more resistant to percutaneous intervention techniques. Ongoing research is evaluating the potential value of newer, more flexible stents as well as the use of covered endoluminal grafts to "reline" diseased arterial segments. It is possible that intimal hyperplasia may be reduced by covering the stent on one or both sides with a fabric such as polytetrafluoroethylene, yielding improvements in long-term patency. A number of device manufacturers have developed Investigational Device Exemption protocols with the Food and Drug Administration to allow randomized comparison of covered grafts and uncovered stents. The use of endoluminal grafts in the treatment of large aneurysms involving the common and internal iliac arteries and the origin of the external iliac artery is also under investigation; this application may prove advantageous, since operative intervention in these locations is often difficult. In addition, the endoluminal graft has been used to manage traumatic or iatrogenic rupture of an iliac artery, and the use of systems incorporating nitinol stents for an "internal" femoropopliteal bypass procedure is also being studied. Although aneurysmal disease in the superficial femoral artery is uncommon, the use of endoluminal grafts now makes it possible to treat these lesions percutaneously with an intraluminal approach; endoluminal graft exclusion of aneurysmal disease in the popliteal artery is also promising.

Aneurysm↗
PubMed1996

Long-term gene transfer in porcine myocardium after coronary infusion of an adeno-associated virus vector.

BACKGROUND: Viral vector-mediated gene transfer into the heart represents a potentially powerful tool for studying both cardiac physiology as well as gene therapy of cardiac disease. We report here the use of a defective viral vector, which expresses no viral gene products, for gene transfer into the mammalian heart. Previous studies have used recombinant viral vectors, which retained viral genes and yielded mostly short-term expression, often with significant inflammation. METHODS: An adeno-associated virus vector was used that contains no viral genes and is completely free of contaminating helper viruses. The adeno-associated virus vector was applied to rat hearts by direct intramuscular injection; adeno-associated virus was also infused into pig hearts in vivo via percutaneous intraarterial infusion into the coronary vasculature using routine catheterization techniques. RESULTS: Gene transfer into rat heart yielded no apparent inflammation, and expression was observed for at least 2 months after injection. Infusion into pig circumflex coronary arteries resulted in successful transfer and expression of the reporter gene in cardiac myocytes without apparent toxicity or inflammation; gene expression was observed for at least 6 months after infusion. CONCLUSIONS: We report the use of adeno-associated virus vectors in the cardiovascular system as well as successful myocardial gene transfer after percutaneous coronary artery infusion of viral vectors in a large, clinically relevant mammalian model. These results suggest that safe and stable gene transfer can be achieved in the heart using standard outpatient cardiac catheterization techniques.

Animals↗
PubMed1996

Stenting in the carotid artery: initial experience in 110 patients.

PURPOSE: To evaluate the feasibility, safety, and efficacy of intravascular stents in the treatment of extracranial carotid artery occlusive disease. METHODS: According to protocol, stent therapy was offered to symptomatic patients with > or = 70% arteriographically defined carotid stenoses or ulcerative lesions and, after September 1994, to asymptomatic patients with > or = 75% stenoses. From April 1993 to September 1995, 110 nonconsecutive patients (79 males; mean age 72 years, range 45 to 85) consented to participate in the study. The majority (79 [72%]) were asymptomatic. Lesions meeting the treatment criteria were in the proximal common (n = 3); mid common (n = 12); distal common (n = 8); internal (ICA) (n = 92); and external (n = 2) carotid arteries. Seven patients had bilateral ICA stenoses, and 17 patients were treated for postsurgical recurrent disease. The mean lesion length and diameter stenosis for all lesions were 12.4 +/- 9.2 mm and 86.5% +/- 10.6%, respectively. The procedures were performed either via direct percutaneous access to the cervical common carotid artery or through a retrograde femoral artery approach. Standard balloon dilation preceded deployment of balloon-expandable stents in most cases. No postprocedural anticoagulation was used (aspirin only). RESULTS: In 110 patients (117 arteries) intended for treatment, 109 (99.0%) (116 arteries [99.1%]) were successfully treated with 129 stents (128 Palmaz, 1 Wallstent). One percutaneous procedure failed (0.9%) for technical reasons (stent could not be deployed) and was converted to carotid endarterectomy. Minor complications included 4 cases of spasm (successfully treated with papaverine); 1 flow-limiting dissection (stented); and 6 access-site problems. There were 7 strokes (2 major, 5 reversible) (6.4%) and 5 minor transient events (4.5%) that resolved within 24 hours. Three patients were converted to endarterectomy (2.7%) prior to discharge; 1 stroke patient expired (0.9%), and another patient died of an unrelated cardiac event in hospital. In the 30-day postprocedural period, 2 ICA stents occluded (patients asymptomatic). Clinical success at 30 days (no technical failure, death, endarterectomy, stroke, or occlusion) was 89.1% (98/110). Over a mean 7.6-month follow-up (range 2 to 31), no new neurological symptoms developed. Another stent occlusion at 2 months and one case of flow-limiting intimal hyperplasia at 7 months were detected on routine duplex scanning in asymptomatic patients. Life-table analysis shows an 89% cumulative primary patency rate. CONCLUSIONS: Based on this early experience, carotid stenting appears feasible from a technical standpoint, with good midterm patency. However, the incidence of neurological sequelae is a serious problem. Technical enhancements and a more aggressive antiplatelet regimen may have a positive impact on these events.

Aged↗
PubMed1996

Percutaneous techniques for endoluminal carotid interventions.

PURPOSE: To describe the evolving techniques for stent implantation in the proximal and cervical carotid arteries. METHODS AND RESULTS: Percutaneous access to proximal and cervical carotid lesions is either via direct puncture of the common carotid artery or through the more familiar retrograde common femoral (RCF) artery approach. Both techniques and their variations are described in detail, along with their benefits, disadvantages, and possible complications. Dual lesions at the arch and higher up the neck can be treated either from the RCF route or, if the cervical lesion requires endarterectomy, with open exposure at the bifurcation and stenting of the proximal lesion. CONCLUSIONS: While the RCF route is more familiar to the majority of interventionists and provides adequate access in most situations, traversing the arch and negotiating acute angles at the ostia of the great vessels may render this method infeasible. The direct puncture technique is a useful alternative; however, it requires more expertise to prevent potentially disastrous access-site complications. One further caveat must be stated: regardless of the access approach selected, the opportunity for serious, debilitating-and lethal-complications is always present in cerebrovascular interventions. At this earliest phase in our experience with carotid stenting, cautious investigative methodologies must prevail.

Angioplasty, Balloon↗
PubMed1996

Intravascular ultrasound assessment in carotid interventions.

PURPOSE: To demonstrate the clinical value of intravascular ultrasound (IVUS) imaging in monitoring stent deployment in the cervical carotid arteries. METHODS AND RESULTS: Two-dimensional (2D) and three-dimensional (3D) IVUS imaging has been used routinely in more than 100 patients following carotid stenting and the completion angiogram to detect evidence of inaccurate stent deployment. Axial 2D views were used to measure diameters and cross-sectional areas and provide the basis for 3D reconstruction. These composited images produced single-frame views of entire vascular segments, with definition of vessel wall morphology, stent placement, and angioplasty-induced defects. This information was used in the decision to apply further treatment to the area in order to maximize luminal diameter and/or correct defects. CONCLUSIONS: IVUS imaging is an important component of carotid artery stent procedures. It more accurately visualizes stent placement and vessel wall morphology than arteriography, information critical to the intraprocedural assessment process.

Angioplasty, Balloon↗
PubMed1995

Major determinants of survival and nonsurvival of intraaortic balloon pumping.

The purpose of this study was to find the major determinants of survival and nonsurvival after intraaortic balloon pump (IABP) support. One hundred twenty-nine consecutive patients with IABP support from January 1988 to January 1992 were analyzed retrospectively. Differences between the survival and nonsurvival groups were tested with the Student's t test, chi-squared test, and frequency analysis. The overall survival rate was 50.4% (65 of 129). Nonsurvivors (64 of 129, 49.6%) had higher rates of chronic heart failure (21.9% vs 9.2%, p < 0.05), acute myocardial infarction (53.1% vs 24.6%, p < 0.01), cardiomyopathy (9.4% vs 1.5%, p < 0.05), New York Heart Association functional class IV (51.6% vs 13.9%, p < 0.01), and depressed left ventricular ejection fraction (29.38% +/- 8.99% vs 42.88% +/- 5.24%, mean +/- SD, p < 0.01). The nonsurvival group also had longer duration of cardiopulmonary bypass (115.80 +/- 24.43 vs 78.34 +/- 3.81 min, mean +/- SEM, p < 0.02) and aortic occlusion (57.55 +/- 13.03 vs 41.00 +/- 2.79 min, mean +/- SEM, p < 0.05) than the survival group. The major determinants of death after IABP are acute myocardial infarction, left ventricular ejection fraction < 30%, New York Heart Association functional class IV, and longer duration of cardiopulmonary bypass and aortic occlusion. IABP is effective in sustaining hemodynamics, but severe myocardial pump failure portends a poor treatment outcome.

Adolescent↗
PubMed1995

Intraluminal Palmaz stent implantation for treatment of recurrent carotid artery occlusive disease: a plan for the future.

While carotid endarterectomy (CEA) has been used commonly and with great effectiveness for de novo carotid occlusive lesions, its success in cases of recurrent disease has been attenuated by a higher incidence of complications and lower durability. Although interventional techniques have been introduced cautiously into the cerebrovascular system, balloon dilation for both primary and recurrent carotid atherosclerotic disease has been successful in establishing an adequate lumen without an increase in embolic complications over surgery. Because the likelihood exists that postdilation restenosis may be as common in the carotid arteries as it is in other vascular segments, the use of intraluminal stenting may mitigate this long-term complication, a benefit that has been demonstrated in other high flow vessels such as the aorta and iliac arteries. To begin an investigation of this hypothesis, we treated a 69-year-old symptomatic man who required a third intervention for recurrent carotid disease. A > 90% stenosis of the distal third of his right common carotid artery was successfully dilated, and a Palmaz stent was deployed without incident. The patient experienced no complications to the percutaneous procedure, and at 15 months posttreatment, he is well and asymptomatic. Although greater clinical experience must be accumulated with this new approach, intraluminal stenting following balloon dilation for recurrent carotid disease may surpass redo CEA in long-term patency and may entail fewer procedural complications.

Aged↗
PubMed1995

Endoluminal grafting for percutaneous aneurysm exclusion in an aortocoronary saphenous vein graft: the first clinical experience.

PURPOSE: Aneurysms develop only rarely in aortocoronary saphenous vein grafts (SVGs), and the usual treatment is surgical replacement of the diseased segment. However, in patients at appreciable risk for redo surgery, alternative therapies are desirable. We report the first compassionate use of a percutaneously delivered endoluminal graft (ELG) for internal exclusion of an SVG aneurysm. METHODS: A 47-year-old male with two coronary bypass procedures and SVG angioplasty presented with an 8-mm diameter aneurysm lying between 80% and 70% stenotic lesions in an SVG to the obtuse marginal branch. The risks of a third bypass operation were considerable, so the decision was made to attempt internal exclusion of the SVG aneurysm. RESULTS: An ELG composed of 2.0-mm diameter unexpanded PTFE graft material with Palmaz stents for fixation was delivered with a low-profile system, but a second ELG was necessary for complete exclusion of the aneurysmal sac. Both ELGs were dilated after initial deployment. The patient was discharged after 9 days without sequelae, and he remains asymptomatic with arteriographically documented ELG patency 5 months after treatment. CONCLUSIONS: In this patient with limited therapeutic options, percutaneous aneurysm exclusion in an SVG was effective in restoring a viable blood conduit. It remains to be seen if ELGs have a potential in aortocoronary SVGs.

Aneurysm↗
PubMed1995

Subclavian stent implantation to alleviate coronary steal through a patent internal mammary artery graft.

PURPOSE: Interventional techniques are rapidly supplanting conventional surgical therapies for the treatment of brachiocephalic occlusive disease. Although coronary-subclavian steal has been successfully alleviated with subclavian angioplasty, we report the first use of a Palmaz stent in the left subclavian artery (SCA) of a patient with a compromised left internal mammary artery (IMA) graft. METHODS AND RESULTS: A 65-year old male patient had undergone triple coronary artery bypass grafting in 1992, but 6 months later, severe narrowing occurred in two of the saphenous vein grafts, and arteriography identified a high-grade stenosis in the SCA supplying the left IMA graft to the left anterior descending coronary artery. Following balloon dilation of one saphenous vein graft stenosis, the left SCA was stented primarily with a P3008 Palmaz stent. Normal hemodynamics were restored, and the patient has been free of coronary steal symptoms for over 1 year. CONCLUSION: This case illustrates yet another aspect to the usefulness of intravascular stents in restoring and maintaining inflow to bypass grafts.

Aged↗