Search

Purpose: To describe a new method of endovascular aneurysm exclusion using a Wallstent-PTFE vascular prosthesis in patients at high risk for surgery., Methods and Results: Two patients with significant comoribidities refused surgery in favor of endoluminal grafting for treatment of aneurysms in the abdominal aorta and popliteal artery, respectively. Both endovascular procedures were performed percutaneously with local anesthesia using a low-profile customized endograft constructed of thin-walled, predilated polytetrafluoroethylene (PTFE) graft mounted on a Wallstent. In both cases, the aneurysm was excluded from the arterial circulation; there were no postprocedural complications. Follow-up evaluation with appropriate imaging at 8 months (popliteal aneurysm) and 2 months (abdominal aneurysm) revealed no endoleaks., Conclusions: Our preliminary results indicate that the Wallstent-PTFE graft, with its smaller diameter and flexible design, offers significant advantages over currently available devices for repair of arterial aneurysms. This method obviates the need for general anesthesia or surgical exposure for arterial repair, which would increase the risk of the procedure in these patients.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Purpose: To report the results of the FDA phase II, multicenter trial of the Wallstent in the iliac and femoral arteries., Patients and Methods: Two hundred twenty-five patients entered the trial. Stents were placed in the iliac system in 140 patients and in the femoral system in 90 (five patients required both iliac and femoral stents). Clinical patency was measured over 2 years by means of life-table analysis with use of clinical and hemodynamic data and the Rutherford scale. Angiographic patency was measured at 6 months., Results: In the iliac system the primary clinical patency was 81% at 1 year and was 71% at 2 years. The secondary clinical patency was 91% and 86%, respectively. The 6-month angiographic patency was 93%. In the femoral system the primary clinical patency was 61% at 1 year and 49% at 2 years. The secondary patency was 84% and 72%, respectively. The 6-month angiographic patency was 80%., Conclusions: The results are similar to those with the Palmaz stent in the iliac system and with angioplasty alone in the iliac and femoral systems.

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.

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.

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.

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.

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.

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.

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.

Today's vascular surgeons are no longer confined to the time-honored progressive triad of exercise, medication, and bypass surgery for the treatment of peripheral vascular disease. Our options have expanded to include primary therapy using thrombolysis, laser angioplasty, atherectomy, balloon dilation, and intravascular stents, most of these tecnological categories featuring several devices from which to select. Coupled with the concomitant development of intraluminal assessment and guidance technologies, namely, intravascular ultrasound (IVUS) and angioscopy, today's vascular specialists can evaluate atherosclerotic disease with greatly enhanced accuracy, deriving far more specific information about an obstruction than was ever required for classical vascular reconstruction. In the end, this new specialty of endovascular surgery will provide results equal to those methods used in the past but with less invasiveness. All these options and a more complex diagnostic database require coordination if these new resources are to be used to their fullest advantage for maximal revascularization. It is now incumbent upon vascular surgeons to appreciate the strategies for selecting endovascular interventions based upon lesion pathology and desired outcome.

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.

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.

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 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.

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.

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.

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.

Late failure of peripheral bypass grafts has been treated primarily by secondary reconstruction. Laser-assisted angioplasty is an optional therapy that the authors investigated in 28 prosthetic grafts over a two-year period. Twenty-five symptomatic patients with 28 peripheral prosthetic arterial bypass grafts (25 polytetrafluoroethylene [PTFE] grafts and 1 each of knitted Dacron, Teflon, and umbilical vein) demonstrated graft occlusion (25) or high-grade stenoses (3). All patients underwent standard laser-assisted angioplasty using a continuous wave Nd:YAG laser source and hybrid probe. Twenty-one grafts (75%) were successfully recanalized with adequate restoration of flow through the conduit. All 7 failures were in occluded PTFE grafts that presented with either recalcitrant lesions (5) or perforations (2) at the distal anastomoses. There have been 3 long-term failures (14%) to date in the successfully treated group, all in PTFE grafts. Two patients suffered recurrent thrombosis and 1 developed an inexplicable graft infection five months after laser treatment. Laser-assisted angioplasty appears to be a clinically viable alternative treatment for prosthetic graft stenosis and recanalization of grafts occluded at their distal anastomosis.

To determine whether foot transcutaneous oxygen tension (TcPO2) and ankle systolic blood pressure (SBP) measure similar aspects of peripheral vascular occlusive disease (PVOD), the authors examined their relationship at rest and following treadmill exercise. Thirty-seven PVOD patients (mean age 69.2 +/- 0.8 years) rested supine for twenty minutes, followed by a progressive treadmill walking test at a constant speed of 2 mph. The initial grade was 0%; this increased 2% every two minutes until maximal claudication pain (n = 19) or until the occurrence of such limiting symptoms as volitional fatigue (n = 6), ST segment depression (n = 4), dyspnea (n = 3), multiple premature ventricular contractions (n = 2), and angina (n = 2). Patients then rested supine for fifteen minutes. Foot TcPO2 was recorded before, during, and after exercise, whereas ankle SBP was measured before and after exercise. At rest, a curvilinear relationship was found between foot TcPO2 and ankle SBP (foot TcPO2 = 41.89 + 0.22(ankle SBP) + 0.0005 (ankle SBP2); SEE = 9.2, R = 0.64, R2 = 0.41, p less than 0.001). In contrast, the relationship was stronger and more linear during recovery, particularly at the sixth minute (foot TcPO2) = 8.33 + 0.35 (ankle SBP); SEE = 13.6, R = 0.86, R2 = 0.73, p less than 0.001). At rest, foot TcPO2 and ankle SBP characterized different aspects of PVOD because they shared only 41% common variance. During recovery, they provided similar information because up to 73% of the variance was shared. It is concluded that foot TcPO2 should also be used to assess PVOD patients because unique information is obtained at rest and values can be recorded during exercise.