Vasopressor use in the critical care unit for treatment of persistent post-carotid artery stent induced hypotension

INTRODUCTION

Hypotension is common following carotid artery stenting (CAS), and may be mediated by vagal stimulation and/or suppression of spinal sympathetic outflow. Both mixed alpha/beta agonists (dopamine (DA)), and more selective alpha- agonists (norepinephrine (NE) and phenylephrine (PE)), have been used, but the most effective treatment of post-CAS hypotension is unknown.

MATERIALS AND METHODS

We analyzed data for consecutive patients requiring vasopressor treatment of post-CAS hypotension. The treating physician made choice of vasopressor. Endpoints included infusion duration, coronary care unit (CCU) length of stay (LOS), and any major adverse events (death, stroke, myocardial infarction, arrhythmia).

RESULTS

During the study period, CAS stenting was performed in 623 patients. CCU admission in atropine non-responders for vasopressor treatment was required in 42 patients (6.7%). DA was used in 20 patients (48%), NE in 13 patients (31%), and PE in nine patients (21%). Vasopressor infusion time was 31.8 +/- 10.6 h for DA, compared with 23.8 +/- 8.1 h for NE (P = 0.052) and 22.1 +/- 6.1 h (P = 0.028) for PE. CCU LOS was 46.5 +/- 14.1 h for DA compared with 36.9 +/- 9.1 h for the NE and PE groups combined (P = 0.056). Major adverse events were more common in patients receiving DA than among patients receiving NE or PE (P = 0.04).

CONCLUSIONS

Compared with DA, treatment of post-CAS hypotension with a selective alpha-agonist (NE or PE) is associated with shorter drug infusion time, shorter CCU LOS, and fewer major adverse events.

Use of stent grafts and coils in vessel rupture and perforation

Vessel rupture and perforation are important complications of percutaneous treatment of coronary and peripheral arterial disease. These complications can result in abrupt vessel closure, distal organ injury, bleeding into the surrounding tissue, and death. Prompt management of such complications is therefore critically important. This paper reviews the management of vessel rupture and perforation, including the use of different types of covered stents (balloon-expandable and self-expanding), as well as the various types of embolization coils. Particular focus will be placed on percutaneous coronary artery and peripheral arterial interventions.

Limitations of percutaneous transluminal angioplasty and stenting for the treatment of disease of the superficial femoral and popliteal arteries

The long-term primary patency rates for percutaneous transluminal angioplasty (PTA) and stenting in treatment of disease of the superficial femoral and popliteal arteries have been disappointing. Three-year primary patency rates of approximately 50% have been reported for PTA and first-generation stents. Early results with newer nitinol stents appear promising; however, long-term data are lacking. One- and 2-year primary patency rates of 76% to 97% and 60% to 84%, respectively, have been reported with nitinol stents. An emerging concern with nitinol stents is the frequency of stent fracture (> or = 25%) after interventions for long-segment disease. A recent study has shown that stent fractures are associated with in-stent restenosis and with significantly lower primary patency at 1 year. The therapeutic success of PTA and stenting correlates with the complexity of the underlying disease. The best results are achieved when treating focal stenoses in patients with good distal runoff. Because endovascular interventions are preferred by patients, can be repeated, and preserve the option of bypass surgery, PTA and stenting are increasingly employed for diffuse and complex SFA disease. Clarifying the role of PTA and stenting in the treatment of complex SFA disease will require future studies that stratify results by both lesion anatomy and treatment indication.

Limb Salvage Following Laser-Assisted Angioplasty for Critical Limb Ischemia:Results of the LACI Multicenter Trial

PURPOSE

To evaluate the effectiveness of laser-assisted angioplasty for patients with critical limb ischemia (CLI) who were poor candidates for surgical revascularization.

METHODS

A prospective registry at 14 sites in the US and Germany enrolled 145 patients with 155 critically ischemic limbs; the patients were poor candidates for bypass surgery owing to inadequate target vessel or saphenous vein, prohibitive cardiac disease, or significant comorbidities (ASA class 4). Additional comorbid risk factors included diabetes in 66%, hypertension in 83%, previous stroke in 21%, and myocardial infarction in 23%. Endovascular treatment included guidewire traversal and excimer laser angioplasty followed by balloon angioplasty with optional stenting.

RESULTS

Occlusions were present in 92% of limbs. A mean of 2.7+/-1.4 lesions were treated per limb; the total median treatment length was 11 cm (mean 16.2, range 0.2-123). Stents were implanted in 45% of limbs. Procedural success, defined as <50% residual stenosis in all treated lesions, was seen in 86% of limbs. At 6-month follow-up, limb salvage was achieved in 110 (92%) of 119 surviving patients or 118 (93%) 127 limbs.

CONCLUSION

Excimer laser-assisted angioplasty for CLI offers high technical success and limb salvage rates in patients unfit for traditional surgical revascularization.

Perforation complicating carotid artery stenting: The use of a covered stent

Carotid artery angioplasty and stenting has emerged as an effective strategy for the treatment of significant carotid artery stenosis. Perforation during carotid artery stenting is a very rare potential complication of the procedure. We describe a case of carotid artery perforation that occurred during postdilation of the carotid artery stent. In our case this potentially serious complication was successfully treated with a covered stent-graft.

Internet-based teleangiography: an indispensable tool for the interventional cardiologist

Efficient and effective communication of specific patient information between referring and consulting physicians has become increasingly important with the need to evaluate a variety of treatment strategies, including coronary bypass surgery, coronary intervention, and medical therapy, without prolonging hospital stay. Until recently, the options available were either slow (mail or courier) or costly and cumbersome (hardware-based digital solutions). eMedcon, a new, easy-to-install Internet-based software solution described in this article, offers a quick and inexpensive solution to image digital cine transfer. eMedcon was tested at our institution, Washington Hospital Center, and was found to transmit images effectively and rapidly between physicians at any Internet-accessible site and Washington Hospital Center. Our data indicate that use of eMedcon led to an increase in repeat referrals and an increase in the number of physicians choosing to refer their patients to our institution.

The Angiomax Peripheral Procedure Registry of Vascular Events Trial (APPROVE): in-hospital and 30-day results

BACKGROUND

High-risk patient characteristics and complexity of percutaneous peripheral intervention (PPI) procedures suggest a need for predictable and reliable anticoagulation. We undertook this study to assess the safety and efficacy of bivalirudin as the procedural anticoagulant in patients undergoing PPI of the renal, iliac, or femoral artery.

METHODS

This was a prospective, open-label, single arm study inpatients undergoing PPI of the renal, iliac, or femoral vessels to assessbivalirudin as the sole procedural anticoagulant (0.75 mg/kg bolus/1.75 mg/kg/hr infusion). The primary endpoint was procedural success defined as residual stenosis < 20%. Secondary endpoints included ischemic events (death, myocardial infarction, unplanned revascularization, and amputation), and bleeding complications, as well as ACT values and times to sheath removal, ambulation, and discharge.

RESULTS

505 patients were enrolled at 26 sites. Procedural success was achieved in 95.0% of patients. Ischemic events were low (1.4%) and similar between vessel types. Protocol-defined major hemorrhage and TIMI major hemorrhage rates were 2.2% and 0.4%, respectively. Mean ACTs were similar among treatment groups (renal 353.8 seconds(s); iliac 335.9s, femoral, 343.5s).

CONCLUSION

Bivalirudin provided consistent anticoagulation and similar outcomes in all vessel types treated at the dose tested. Ischemic and bleeding event rates were low, demonstrating the safe use of bivalirudin as a procedural anticoagulant in PPI.

Usefulness of optical coherent reflectometry with guided radiofrequency energy to treat chronic total occlusions in peripheral arteries (the GRIP trial)

Optical coherent reflectometry, a forward-looking, fiberoptic-guided device was used in 72 patients to direct radiofrequency energy across the central intraluminal portion of 75 chronic total occlusions in peripheral arteries (iliac, femoral, and popliteal) that failed attempts with conventional guidewires. The system was successful in crossing 76% of the chronic total occlusions with no clinical perforations or distal embolizations, and complications consisted of a single dissection greater than or equal to grade C.

Renal Artery Stenting Using Gadodiamide Arteriography in Patients with Baseline Renal Insufficiency

PURPOSE

To investigate whether a contrast agent containing gadodiamide can reduce the incidence of contrast-induced nephropathy associated with renal artery stenting in patients with preexisting renal insufficiency.

METHODS

Between 1999 and 2002, gadodiamide-based arteriography was used in 20 patients (12 men; mean age 69 years) with significant baseline renal insufficiency (creatinine > or =1.7 mg/dL) undergoing renal artery stenting for > or =70% stenoses in 25 renal arteries. Baseline creatinine levels were compared to postprocedure and midterm follow-up levels.

RESULTS

Procedural success was 100%. An average of 74 mL of gadodiamide contrast was used per case. Four patients received an additional 30 mL (mean) of iodinated contrast due to poor image quality with gadodiamide alone. There was no significant change in mean creatinine levels at discharge (2.9 mg/dL) compared to baseline (3.0 mg/dL, p=0.72). At midterm follow-up, mean creatinine levels (2.4 mg/dL) were significantly lower compared to baseline (p=0.004).

CONCLUSIONS

Gadodiamide-based arteriography can be effectively used during RAS in patients with baseline renal insufficiency. This technique may enhance the renal-protective effect of renal artery stenting in this high-risk population with renal artery stenosis.

Excimer laser assisted angioplasty for the treatment of critical limb ischemia

Two decades after the clinical introduction of percutaneous transluminal angioplasty (PTA), controversy still exists about the role of PTA for the treatment of occlusive disease in the femoropopliteal and infragenicular arteries. For the patient with critical limb ischemia (CLI), where diffuse disease and long occlusions are the rule, the results with PTA have not been optimal. Surgical revascularization has long been considered the gold standard for this patient population, but this procedure is associated with significant morbidity and mortality and up to 37% of patients may be poor surgical candidates. With advances in laser catheter design and refinement of recanalization techniques, improved results have been seen with laser assisted angioplasty of complex peripheral arterial disease. There has been renewed interest in excimer laser angioplasty for the treatment of patients with long total occlusions and diffuse disease who otherwise would have limited options for treatment. Excimer laser assisted angioplasty has been shown to be a successful approach to the treatment of long occlusions in the superficial femoral artery. Data from the recently completed Laser Angioplasty for Critical Limb Ischemia Phase 2 Trial (LACI) suggest that this is a viable treatment strategy for patients with CLI who are otherwise not good candidates for bypass surgery.

Intravascular ultrasound analysis of infarct-related and non-infarct-related arteries in patients who presented with an acute myocardial infarction

BACKGROUND

Previous studies have reported diffuse destabilization of atherosclerotic plaques in acute myocardial infarction (AMI).

METHODS AND RESULTS

We used intravascular ultrasound (IVUS) to assess 78 coronary arteries (38 infarct-related arteries [IRAs] with culprit and nonculprit lesions and 40 non-IRAs) from 38 consecutive AMI patients. IVUS analysis included qualitative and quantitative measurements of reference and lesion external elastic membrane (EEM), lumen, and plaque plus media (P&M) area. Positive remodeling was defined as lesion/mean reference EEM >1.0. Culprit lesions were identified by a combination of ECG, wall motion abnormalities (ventriculogram or echocardiogram), scintigraphic perfusion defects, and coronary angiogram. Culprit lesions contained more thrombus (23.7% versus 3.4% in nonculprit IRA plaques and 3.1% in non-IRA plaques; P=0.0011). Culprit lesions were predominantly hypoechoic (63.2% versus 37.9% of nonculprit IRA plaques and 28.1% of non-IRA plaques; P=0.0022). Culprit lesions were longer (17.5+/-10.1, 9.8+/-4.0, and 10.3+/-5.7 mm, respectively; P<0.0001), had larger EEM area (15.0+/-6.0, 11.5+/-5.7, and 12.6+/-5.6 mm2, respectively; P=0.0353) and P&M area (13.0+/-6.0, 7.5+/-3.7, 9.3+/-4.3 mm2, respectively; P<0.0001), smaller lumens (2.0+/-0.9, 4.1+/-3.1, and 3.4+/-2.5 mm2, respectively; P=0.0009), and more positive remodeling (79.4%, 59.0%, and 50.8%, respectively; P=0.0155). The frequency of plaque rupture/dissection was greater in culprit, nonculprit IRA, and non-IRA plaques in AMI patients than in a control group of chronic stable angina patients with multivessel IVUS imaging.

CONCLUSIONS

Culprit plaques have more markers of instability (thrombus, positive remodeling, and large plaque mass); however, these markers of instability are not typically found elsewhere. This suggests that the vascular event in AMI patients is determined by local pre-event lesion morphologies.

Mechanism of lumen enlargement with direct stenting versus predilatation stenting: influence of remodelling and plaque characteristics assessed by volumetric intracoronary ultrasound

OBJECTIVE

To compare the effects of arterial remodelling and plaque characteristics on the mechanisms of direct stenting and predilatation stenting. Direct stenting has become routine in some laboratories and differs technically from predilatation stenting.

METHODS

Pre- and post-interventional volumetric intravascular ultrasound (IVUS) was undertaken in 30 patients with direct stenting and in 30 with predilatation stenting of non-calcified native coronary lesions, using the same stent design and stent length. Lumen, vessel (external elastic membrane (EEM)), and plaque (plaque + media) volumes were calculated. Remodelling was determined by comparing the EEM area at the centre of the lesion with the EEM areas at proximal and distal reference sites. Plaque eccentricity was defined as the thinnest plaque diameter to the thickest plaque diameter ratio. Plaque composition was characterised as soft, mixed, or dense.

RESULTS

All volumetric IVUS changes were similar in the two groups. Pre-intervention remodelling remained uninfluenced after direct stenting, but was neutralised after predilatation stenting. Eccentric lesions responded to intervention by a greater luminal gain owing to greater vessel expansion in direct stenting. Plaque composition influenced luminal gain in direct stenting, the gain being greatest in the softest plaques; in predilatation stenting, luminal gain was equivalent but vessel expansion was greater for "dense" plaque and plaque reduction greater for "soft" plaque.

CONCLUSIONS

In non-calcified lesions, the mechanisms of lumen enlargement after direct or predilatation stenting are significantly influenced by atherosclerotic remodelling, plaque eccentricity, and plaque composition.

Complex endovascular treatment for critical limb ischemia in poor surgical candidates: a pilot study

PURPOSE

To evaluate the effectiveness of complex endovascular treatment for limb salvage in patients with critical limb ischemia.

METHODS

In a prospective study, 23 patients (13 men; mean age 70 +/- 11 years, range 44-87) with ischemic ulceration or gangrene of 25 lower limbs were enrolled at 4 sites to evaluate treatment with excimer laser recanalization followed by balloon angioplasty with optional stenting in the superficial femoral, popliteal, and/or tibial arteries.

RESULTS

Multiple lesions (mean 3.1, range 1-8) were treated in most cases. Reduction of stenosis/occlusion to <50% was achieved in 22 (88%) limbs. Individual cases of vessel perforation, inability to cross the lesion, and excessive residual stenosis accounted for the 3 failures. Over a 6-month period, 4 patients died of cardiac comorbidity and 1 was lost to follow-up. Adverse events included 4 minor and 2 below-knee amputations, 4 secondary angioplasties, and 4 femorodistal bypasses. The mean wound area reduction was 70% at 3 months, increasing to 89% at 6 months. According to life table analysis, the limb salvage rate was 90% with bypass and 69% without in the successfully treated patients (corresponding intention-to-treat rates were 79% and 61%).

CONCLUSIONS

Complex endovascular treatment combining laser debulking and angioplasty/stenting offers an alternative for patients with critical limb ischemia who lack good surgical options.

Morphologic and angiographic features of coronary plaque rupture detected by intravascular ultrasound

OBJECTIVES

This study was designed to report the clinical and angiographic correlates of plaque rupture detected by intravascular ultrasound (IVUS).

BACKGROUND

Acute coronary syndromes result from spontaneous plaque rupture and thrombosis.

METHODS

We report 300 plaque ruptures in 257 arteries in 254 patients. Plaque ruptures were detected during pre-intervention IVUS. Standard clinical, angiographic, and IVUS parameters were collected and/or measured. One lesion per patient was analyzed.

RESULTS

Multiple ruptures were observed in 39 of 254 patients (15%), 36 in the same artery. Plaque rupture occurred not only in patients with unstable angina (46%) or myocardial infarction (MI, 33%), but also stable angina (11%) or no symptoms (11%). The tear in the fibrous cap could be identified in 157 of 254 patients; 63% occurred at the shoulder of the plaque and 37% in the center of the plaque. Thrombi were more common in patients with unstable angina or MI (p = 0.02) and in multiple ruptures (p = 0.04). The plaque rupture site contained the minimum lumen area (MLA) site in only 28% of patients; rupture sites had larger arterial and lumen areas and more positive remodeling than MLA sites. Intravascular ultrasound plaque rupture strongly correlated with complex angiographic lesion morphology: ulceration in 81%, intimal flap in 40%, thrombus in 7%, and aneurysm in 7%.

CONCLUSIONS

Plaque ruptures occur with varying clinical presentations, strongly correlate with angiographic complex lesion morphology, may be multiple, and usually do not cause lumen compromise.

Incidence, morphology, angiographic findings, and outcomes of intramural hematomas after percutaneous coronary interventions: an intravascular ultrasound study

BACKGROUND

Intramural hematomas during percutaneous coronary intervention (PCI) have not been well studied.

METHODS AND RESULTS

We used intravascular ultrasound to determine the incidence, morphology, and clinical features of post-PCI intramural hematomas. In 905 patients with 1025 consecutive native coronary artery, non-in-stent restenosis lesions undergoing PCI, 72 hematomas were detected in 69 arteries in 68 patients. The incidence of intramural hematomas per artery was 6.7% (69 of 1025); 36% (26 of 72) involved the proximal reference artery, 18% (13 of 72) were confined to the lesion, and 46% (33 of 72) involved the distal reference artery. The entry site from the lumen into the hematoma was identified in 86% of hematomas (62 of 72) and had the appearance of a dissection into the media. Conversely, a re-entry site was identifiable in only 8% (6 of 72). The axial extension of the hematoma was distal in 63% and proximal in 37%. In 60% of the hematomas (42 of 72) the angiogram had the appearance of a dissection; in 11% (8 of 72), it appeared to be a new stenosis; and in 29% (22 of 72), no significant abnormality was detected. Non-Q-wave myocardial infarctions occurred in 26% of patients (17 of 65). In 3 patients, the creatine kinase-MB was not measured during the hospital stay. Repeat revascularization occurred in 2 patients in-hospital, 2 additional patients at 1 month, and 8 additional patients at 1 year. There were 3 sudden deaths at 1 year.

CONCLUSIONS

Intravascular ultrasound identified intramural hematomas after 6.7% of PCIs. The mechanism appeared to be a dissection into the media where blood accumulated because of a lack of re-entry. A third of ultrasound-identified hematomas showed no angiographic abnormalities. There was a high rate of non-Q-wave myocardial infarction, need for repeat revascularization, and sudden death in patients with hematomas.

Prognostic value of cardiac troponin I elevation after percutaneous coronary intervention in patients with chronic renal insufficiency: a 12-month outcome analysis

Serum cardiac troponin I (cTnI) is a highly specific marker for myocardial damage in patients with chronic renal insufficiency (CRI), unlike creatine kinase myocardial band fraction (CK-MB), which may be elevated in the absence of myocardial injury in patients with CRI. We studied 116 consecutive CRI patients (serum creatinine +/- 1.8 mg/dL, not on dialysis) with normal baseline cTnI levels who underwent successful percutaneous coronary intervention (PCI). Patients were divided into two groups: group 1, elevated postprocedural cTnI (n = 50), and group 2, normal cTnI (n = 66). Patients with elevated cTnI were older and had a higher incidence of postinfarction angina and lower creatinine clearance compared to patients who did not have cTnI elevation. Atheroablative devices (rotational and directional atherectomy and excimer laser coronary angioplasty) were more frequently used in group 1 patients (27.1% vs. 18.5%; P = 0.04). In-hospital mortality, cardiac mortality, and Q-wave myocardial infarction rates did not differ between the two groups. At 12-month follow-up, total mortality rates were significantly higher in group 1 (28.0% vs. 9.9%; P = 0.002). Multivariate analysis showed that cTnI was an independent predictor of late mortality (OR = 2.26; CI = 1.07-4.77; P = 0.03). Thus, in patients with CRI, elevated cTnI levels after successful PCI is an important predictor of poor long-term outcome. Our data suggest that patients with cTnI elevation > 3 times above normal values are particularly at higher risk.

Transient contrast encephalopathy after carotid artery stenting

PURPOSE

To report an unusual case of transient contrast encephalopathy arising after carotid artery stenting.

CASE REPORT

An 82-year-old right-handed man with a recent history of transient ischemic events was admitted to the hospital for evaluation of carotid artery disease. During cerebral angiography, which identified a 90% right internal carotid artery stenosis, the patient received 25 mL of an ionic, low-osmolar contrast agent (ioxaglate) in each carotid artery. The following day he underwent successful carotid stenting, during which 180 mL of ioxaglate were used. He developed rapidly worsening confusion and left hemiparesis on the table. Noncontrast computed tomography showed marked cortical enhancement and edema of the right cerebral hemisphere in the distribution of the right anterior and middle cerebral arteries. The patient improved rapidly and by day 2 was completely recovered; magnetic resonance imaging documented no cortical edema and normal sulci. One month after the procedure, he was well, with patent carotid arteries.

CONCLUSIONS

Transient neurotoxicity after carotid interventions must be differentiated from massive cerebral infarction and hyperperfusion syndrome, but the prognosis is excellent. However, subsequent contrast studies in a patient with this complication should be undertaken with extreme caution.

The management of acute limb ischemia: techniques for dealing with thrombus

Acute limb ischemia (ALI) has long been a major clinical problem, producing significant risks for limb loss and death. It is most commonly caused by arterial thrombosis in the setting of underlying atherosclerotic peripheral vascular disease or by arterial embolism, usually of cardiac origin. Over the past several decades, preferred treatment options for ALI have alternated between medical and surgical approaches. More recently, direct intra-arterial thrombolysis became the standard of care after several randomized trials demonstrated the benefit of this approach as compared with acute surgical intervention. Despite all of the experience with direct intra-arterial thrombolysis for the treatment of ALI, the optimal thrombolytic approach not been clearly established. Current investigation is directed at identifying the ideal thrombolytic agent for this purpose and the appropriate dosing regimen. In addition, there is interest in the newer mechanical thrombectomy devices and the use of platelet glycoprotein IIb/IIIa inhibitors to speed the time to reperfusion of the acutely ischemic limb.

Percutaneous arterial aortoiliac intervention

Historically reconstructive vascular surgery, has been a cornerstone of treatment for symptomatic obliterative aortoiliac disease. Surgical results include a reported aortobifemoral bypass 5-year patency rate from 85% to 90% and a 10-year patency rate of 70% to 75%. Operative mortality for aortoiliac reconstruction ranges from 1.6% to 3.3%, with an aggregated systemic morbidity of 8.3%. Clinical indications for surgical intervention are well-established and are limited primarily to severe claudication and limb-threatening ischemia. Broader application of surgical intervention is not recommended because of significant morbidity and mortality associated with the procedure. As balloon angioplasty and endovascular stenting technologies evolve, they are proving to be an effective modality for the treatment of aortoiliac disease. These lower risk procedures have allowed expansion of traditional indications for intervention. Treatment is recommended presently for patients with clinical symptoms that impact lifestyle and professional requirements. Less conventional indications include allowing access for coronary intervention or for placement of an intra-aortic balloon pump, or improving inflow prior to a distal surgical bypass procedure. Results of aortoiliac percutaneous interventions are difficult to compare with surgical data since methods and technology continue to improve and evolve, and randomized studies are limited. It is clear that as long as outcomes of percutaneous interventions are predictable and secondary patency rates acceptable, the low complication rates of a percutaneous intervention are clearly preferable to a riskier surgical alternative.

Intravascular radiation therapy after balloon angioplasty of narrowed femoropopliteal arteries to prevent restenosis: results of the PARIS feasibility clinical trial

PURPOSE

To conduct a feasibility study to assess the feasibility, safety, and outcome of endoluminal gamma radiation therapy after balloon angioplasty of superficial femoral artery (SFA) lesions.

MATERIALS AND METHODS

Forty patients with claudication were enrolled in the study and underwent percutaneous transluminal angioplasty (PTA) of SFA lesions with a mean lesion length of 9.8 cm +/- 3.0 and a mean reference vessel diameter of 5.2 mm +/- 3.1. After successful PTA, a segmented centering balloon catheter was positioned to cover the PTA site. The patients were then transported to the radiation oncology suite and treated with a microSelectron HDR afterloader with use of an Ir-192 source with a prescribed dose of 14 Gy, 2 mm into the vessel wall. Ankle-brachial index (ABI) and Rutherford score were evaluated at 1, 6, and 12 months after the procedure and angiographic follow-up was conducted at 6 months.

RESULTS

Radiation was delivered successfully to 35 of 40 patients. There were no procedural complications. Exercise and rest ABI were higher at 1 year (0.72 +/- 0.26 and 0.89 +/- 0.18, respectively) compared to baseline (0.51 +/- 0.25 and 0.67 +/- 0.17, respectively). Maximum walking time on a treadmill increased from 3.41 min +/- 2.41 to 4.43 min +/- 2.49 at 30 days and was 4.04 min +/- 2.8 at 12 months. The angiographic binary restenosis rate at 6 months was 17.2% and the clinical restenosis rate at 12 months was 13.3%. There were no angiographic or clinical adverse events related to the radiation therapy.

CONCLUSIONS

Intraarterial radiation after PTA of SFA lesions with use of high-dose rate gamma radiation is feasible and safe. The angiographic and clinical improvements are sustainable at 1 year and represent a potent antirestenotic therapy for the treatment of narrowed peripheral arteries.

Intravascular ultrasound assessment of the stenoses location and morphology in the left main coronary artery in relation to anatomic left main length

Eighty-seven left main stenoses were evaluated by angiography and intravascular ultrasound. Intravascular ultrasound analysis included left main length (bifurcation to ostium), stenosis location, stenosis length, stenosis external elastic membrane, lumen, plaque & media cross-sectional area (CSA), plaque burden (plaque & media/external elastic membrane CSA), calcium arc, calcium length, eccentricity, and remodeling index (stenosis/reference external elastic membrane CSA). Long anatomic left main arteries (length > or =10 mm, n = 43) were compared with short anatomic left main arteries (length <10 mm, n = 44) regarding stenosis location. Ostial (proximal third of left main artery) (n = 32) and nonostial (midthird and distal third) stenoses (n = 55) were compared regarding stenosis morphology. Short anatomic left main arteries developed stenoses more frequently near the ostium (ostium 55%, bifurcation 38%). Conversely, long anatomic left main arteries developed stenoses more frequently near the bifurcation (ostium 18%, bifurcation 77%, p = 0.001). Ostial left main stenoses were more common in women (44% vs 20%, p = 0.02), had larger lumen area (6.2 +/- 2.2 vs 4.6 +/- 2.3 mm(2), p = 0.002), less plaque burden (62 +/- 15% vs 80 +/- 9%, p <0.0001), less calcification (arc = 78 +/- 65 degrees vs 195 +/- 101 degrees, p <0.0001), and more negative remodeling (remodeling index = 0.87 +/- 0.19 vs 1.01 +/- 0.21, p = 0.005) than nonostial left main stenoses. Most ostial left main stenoses were categorized as eccentric (97% vs 76%, p = 0.01). Short and long left main arteries develop stenoses at different locations. Stenosis morphology was significantly different in these 2 locations.

Intravascular ultrasound-guided renal artery stenting

PURPOSE

To evaluate the clinical outcomes of patients undergoing renal artery stenting with intravascular ultrasound (IVUS) guidance and compare measurements between IVUS and angiography.

METHODS

One hundred thirty-one patients (71 women; mean age 71 +/- 8 years) underwent IVUS-guided Palmaz stent implantation in 153 stenotic renal arteries at a single center. The indications for stenting were uncontrolled hypertension (102, 77.9%), renal insufficiency (10, 7.6%), and both conditions (19, 14.5%). The majority of lesions were ostial (114, 74.5%); the remainder occupied the proximal renal artery (39, 25.5%). The mean lesion length and diameter stenosis were 6.5 +/- 3.0 mm and 74% +/- 10%, respectively, as measured by angiography. Data were recorded in a prespecified database; angiographic and IVUS images were analyzed at dedicated core laboratories and compared.

RESULTS

Angiographic success was achieved in all patients, but IVUS indicated the need for additional intervention in 36 (23.5%) cases. There was strong correlation between the angiographic and IVUS measurements of lesion length (r = 0.60, p < 0.0001) and pre-/postprocedural minimal luminal diameter (r = 0.72 and 0.63, respectively; p < 0.0001). The mean contrast volume was 74 +/- 18 mL per case. In-hospital renal failure occurred in 8 (6.1%) patients; 2 (1.5%) required transient hemodialysis. At a mean 15-month follow-up, patients were treated with fewer antihypertensive medications (p = 0.05), and systolic and diastolic arterial blood pressures had decreased (p = 0.001); no significant change was noted in serum creatinine.

CONCLUSIONS

IVUS-guided stenting facilitates safe renal artery revascularization. IVUS imaging may complement angiography in certain cases, which should be studied further in prospective studies with iodinated or noniodinated contrast agents.

Carotid artery stenting in patients with high-risk anatomy for carotid endarterectomy

PURPOSE

To report the results of carotid artery stenting (CAS) in patients considered to have high-risk anatomical characteristics for carotid endarterectomy.

METHODS

CAS was performed in 39 carotid arteries of 37 consecutive patients (26 men; mean age 72 +/- 8 years, range 56-88) who met the criteria for high-risk surgical anatomy: previous ipsilateral carotid endarterectomy (20/39, 51.3%), common carotid bifurcation above the mandibular angle (5/39, 12.8%), contralateral carotid artery occlusion (15/39, 38.5%), or previous radiation therapy to the neck (1/39, 2.6%). Palmaz, Integra, or Wallstents were deployed via a percutaneous femoral artery access. Independent neurological evaluation was performed at specified time points, and a dedicated committee adjudicated all clinical events.

RESULTS

Procedural success was 100%, with no major in-hospital complications. Neurological events were rare. Only 1 (2.6%) transient ischemic attack occurred prior to discharge; at 30 days, 1 (2.6%) additional minor stroke had been observed, giving a 2.6% cumulative 30-day "death plus any stroke" rate. Over a mean 11 +/- 6-month follow-up, 2 (5.4%) patients died of nonneurological causes, but there were no strokes.

CONCLUSIONS

CAS is a viable endovascular revascularization technique that can be performed safely and effectively in patients with high-risk anatomy for carotid endarterectomy.

Postprocedural hypotension after carotid artery stent placement: predictors and short- and long-term clinical outcomes

PURPOSE

To describe the predictors of persistent hypotension after carotid artery stent (CAS) placement and define the clinical outcome of patients with this hemodynamic disturbance.

MATERIALS AND METHODS

One hundred forty CAS procedures were performed in 133 consecutive patients. Post-CAS hypotension-defined as a greater than 40 mm Hg decrease in arterial pressure without evidence of hypovolemia, with a systolic pressure lower than 90 mm Hg at the end of CAS and lasting at least 1 hour-was observed in 25 patients (group 1); 108 patients did not have hypotension (group 2).

RESULTS

Post-CAS hypotension developed in 33.9% of cases after balloon-expandable stent placement versus in 13.6% of cases after self-expanding stent placement (P =.04). In-hospital minor ipsilateral strokes occurred in 16% of cases in group 1 versus in 3% of cases in group 2 (P =.03). There was one (0.9%) major stroke (transient) and three (2.6%) transient ischemic attacks, all of which occurred in group 2 (not significant vs group 1 for both conditions). At 10 months +/- 4 (SD) of follow-up, there was greater total mortality in group 1 than in group 2 (20% vs 4%, P =.02), whereas neurologic events did not differ significantly between the groups.

CONCLUSION

Hypotension due to carotid sinus stimulation is frequent after CAS with balloon-expandable stents. This phenomenon correlates with increased in-hospital complications and long-term risk of death.

Intra-arterial reteplase for the treatment of acute limb ischemia

The removal of urokinase from the market has created a dilemma for interventionists and vascular surgeons treating patients with acute limb threatening ischemia due to arterial thrombosis or embolization. Reteplase is a newer, fibrin-specific thrombolytic agent with properties that make it an attractive alternative to urokinase. We report two cases of successful treatment of acute, limb threatening ischemia with intra-arterial Reteplase therapy.

Treatment of symptomatic cervical carotid dissections with endovascular stents

OBJECTIVE

Symptomatic dissections of the cervical carotid artery (CCA) can be spontaneous or secondary to trauma and may be associated with pseudoaneurysms. Surgical treatment is often difficult or unavailable. We report the successful use of endovascular stents in the treatment of symptomatic dissection of the CCA.

METHODS

Five consecutive patients with symptomatic CCA dissection were seen at our institution. There were four female patients and one male patient, ranging in age from 19 to 56 years. One dissection was spontaneous. The others were secondary to a gunshot wound (one patient), blunt neck trauma (two patients), and endovascular treatment of atherosclerotic carotid bifurcation disease (one patient). Balloon-expandable and self-expanding stents were placed via a transfemoral approach.

RESULTS

Success in restoring the carotid lumen with two to five stents in each patient was angiographically demonstrated. There were no procedure-related complications. All patients experienced significant clinical improvement within the first 24 hours and complete long-term recovery.

CONCLUSION

Symptomatic dissections of the CCA can be successfully treated by using endovascular stents.

Progressive vascular remodeling and reduced neointimal formation after placement of a thermoelastic self-expanding nitinol stent in an experimental model

Despite the improvements afforded by intracoronary stenting, restenosis remains a significant problem. The optimal physical properties of a stent have not been defined. We compared the vascular response to a thermoelastic self-expanding nitinol stent with a balloon-expandable tubular slotted stainless steel stent in normal porcine coronary arteries. Twenty-two stents (11 nitinol and 11 tubular slotted) were implanted in 11 miniature swine. The nitinol stents were deployed using the intrinsic thermal properties of the metal, without adjunctive balloon dilation. The tubular slotted stents were implanted using a noncompliant balloon with a mean inflation pressure of 12 atm. Intravascular ultrasound (IVUS) and histology were used to evaluate the vascular response to the stents. The mean cross-sectional area (CSA) of the nitinol stents (mm2) as measured by IVUS increased from 8.13 +/- 1.09 at implant to 9.10 +/- 0.99 after 28 days (P = 0.038), while the mean CSA of the tubular slotted stents was unchanged (7.84 +/- 1.39 mm2 vs. 7.10 +/- 1.07 mm2, P = 0.25). On histology at 3 days, the tubular slotted stents had more inflammatory cells adjacent to the stent wires (5.7 +/- 1.5 cells/0.1 mm2) than the nitinol (3.9 +/- 1.3 cells/0.1 mm2, P = 0.016). The tubular slotted also had increased thrombus thickness (83 +/- 85 microm) than the nitinol stents (43 +/- 25 microm, P = 0.0014). After 28 days, the vessel injury score was similar for the nitinol (0.6 +/- 0.3) and the tubular slotted (0.5 +/- 0.1, P = 0.73) designs. The mean neointimal area (0.97 +/- 0.46 mm2 vs. 1.96 +/- 0.34 mm2, P = 0.002) and percent area stenosis (15 +/- 7 vs. 33 +/- 7, P = 0.003) were significantly lower in the nitinol than in the tubular slotted stents, respectively. We conclude that a thermoelastic nitinol stent exerts a more favorable effect on vascular remodeling, with less neointimal formation, than a balloon-expandable design. Progressive intrinsic stent expansion after implant does not appear to stimulate neointimal formation and, therefore, may provide a mechanical solution to prevent in-stent restenosis.

Procedural results and late clinical outcomes after placement of three or more stents in single coronary lesions

BACKGROUND

Previous reports have suggested higher procedural and long-term complications among patients treated with multiple stents for diffuse lesions and/or long dissections.

METHODS AND RESULTS

To evaluate procedural success, major complications, and clinical outcomes (> or = 1 year) in a consecutive series of patients treated with multiple (> or = 3) contiguous stents in single lesions, we evaluated in-hospital and long-term (1-year) clinical outcomes in 117 consecutive patients treated with > or = 3 coronary stents compared with a concurrent series of patients treated with 1 or 2 stents (n=1673) between January 1, 1994, and December 31, 1995. Multiple stents were implanted more often in larger vessels, in the right coronary artery or saphenous vein grafts, and for unfavorable lesion characteristics, including long (>20 mm), calcified, ulcerated, thrombotic, and/or flow-obstructing lesions. Overall procedural success was obtained in 97.4% of patients and was similar whether 1 or 2 versus > or = 3 stents were used. Non-Q-wave MI (CK-MB > or = 5 times normal) was more frequent after > or = 3 stents (22.8% versus 13.4%, P=.005). Target lesion revascularization (TLR) was 14.6% for 1 or 2 stents and 13.3% for > or = 3 stents (P=.70). There was no difference in death (2.2% versus 0.9%, P=.34) or Q-wave MI (1.4% versus 0.9%, P=.64) between the two groups (1 or 2 stents versus > or = 3 stents, respectively), and overall cardiac event-free survival was similar during follow-up (P=.70).

CONCLUSIONS

Patients treated with multiple (> or = 3) contiguous stents compared with 1 or 2 stents have (1) similar in-hospital procedural success and major complications despite having more unfavorable lesion characteristics, (2) a higher rate of procedural non-Q-wave MI, and (3) similar TLR and overall major cardiac event rates during 1 year of follow-up.

Lipid-lowering therapy after coronary revascularization: the interventional cardiologist's perspective

Despite the success of coronary interventions in the treatment of stenosis due to coronary atherosclerosis, it behooves cardiologists to treat the underlying disease by decreasing patients' cholesterol levels. Intravascular ultrasound has made it possible to detect plaque accumulation not visible on angiography. Although advanced lesions that are fibrous and calcific can be treated with atherectomy and lasers, it is the soft, lipid-laden plaque that is particularly vulnerable to rupture and leads to coronary events. Therefore, attention must also focus on decreasing atherosclerotic progression in patients who have undergone coronary interventions. Studies have clearly shown the value of cholesterol reduction in decreasing coronary events. However, a review of cardiologists' practices shows that more aggressive lipid-lowering therapy is needed. One way to achieve this goal is to treat and monitor patients who have undergone revascularization procedures and to encourage patients to become more involved in their own care.

Comparative early and nine-month results of rotational atherectomy, stents, and the combination of both for calcified lesions in large coronary arteries

The aim of this study was to determine the preferred treatment modality for calcified lesions in large (> or = 3 mm) coronary arteries, resulting in the largest lumen dimensions and the most favorable late clinical responses. Three hundred six lesions in 306 patients (223 men, mean age 66 +/- 11 years) were treated with either rotational atherectomy plus adjunct balloon angioplasty (n = 147), Palmaz-Schatz stents (n = 103), or a combination of rotational atherectomy plus adjunct Palmaz-Schatz stents (n = 56). The procedural success rate was 98.0% to 98.6% for each treatment modality. Minimal lumen diameter (MLD) before therapy was similar for all therapies. Final MLD after combination of rotational atherectomy plus Palmaz-Schatz stents was larger than after stent therapy or rotational atherectomy plus balloon angioplasty (3.21 +/- 0.49 mm, 2.88 +/- 0.51 mm, and 2.29 +/- 0.55 mm, respectively, p <0.0001). Correspondingly, final percent diameter stenosis was lowest after the combination of rotational atherectomy plus stent therapy, and significantly higher for stents or rotational atherectomy plus balloon angioplasty (4.2 +/- 15.3%, 14.1 +/- 13.3%, and 26.7% +/- 16.9%, respectively, p <0.0001). Event-free survival at 9 months was higher for patients treated with the combination of rotational atherectomy plus stents than either stent therapy or rotational atherectomy alone (85%, 77%, and 67%, respectively, log-rank p = 0.0633). The only significant independent predictor of an event during the 9-month follow-up period was the MLD after intervention (odds ratio 0.495, 95% confidence interval 0.308 to 0.796, p = 0.0037). We conclude that preatheroablation using rotational atherectomy, followed by adjunct stent placement for calcified lesions in large arteries, is associated with infrequent complications, the largest acute angiographic results, and the most favorable late clinical event rates.

Effects of endovascular radiation from a beta-particle-emitting stent in a porcine coronary restenosis model. A dose-response study

BACKGROUND

Neointimal formation causes restenosis after intracoronary stent placement. Endovascular radiation delivered via a stent has been shown to reduce neointimal formation after placement in porcine and rabbit iliac arteries. The objective of this study was to evaluate the dose-related effects of a beta-particle-emitting radioactive stent in a porcine coronary restenosis model.

METHODS AND RESULTS

Thirty-seven swine underwent placement of 35 nonradioactive and 39 beta-particle-emitting stents with activity levels of 23.0, 14.0, 6.0, 3.0, 1.0, 0.5, and 0.15 microCi of 32P. Treatment effect was assessed by histological analysis 28 days after stent placement. Neointimal and medial smooth muscle cell density were inversely related to increasing stent activity. The neointima of the high-activity (3.0- to 23.0-microCi) stents consisted of fibrin, erythrocytes, occasional inflammatory cells, and smooth muscle cells with partial endothelialization of the luminal surface. In the 1.0-microCi stents, the neointima was expanded and consisted of smooth muscle cells and a proteoglycan-rich matrix. The neointima of the low-activity (0.15- and 0.5-microCi) stents was composed of smooth muscle cells and matrix with complete endothelialization of the luminal surface. At low and high stent activities, there was a reduction in neointimal area (low, 1.63 +/- 0.67 mm2 and high, 1.73 +/- 0.97 mm2 versus control, 2.40 +/- 0.87 mm2) and percent area stenosis (low, 26 +/- 7% and high, 26 +/- 12%) compared with control stents (37 +/- 12%, P < or = .01). The 1.0-microCi stents, however, had greater neointimal formation (4.67 +/- 1.50 mm2) and more luminal narrowing (64 +/- 16%) than the control stents (P < .0001).

CONCLUSIONS

The differential response to the doses of continuous beta-particle irradiation used in this experimental model suggests a complex biological interaction of endovascular radiation and vascular repair after stent placement. Further study is required to determine the clinical potential for this therapy to prevent stent restenosis.

Experimental results with endovascular irradiation via a radioactive stent

PURPOSE

The objective of this article is to describe the methods used to manufacture a radioactive stent and to review the experimental data on this therapy designed to improve arterial patency rates after stent placement.

MATERIALS AND METHODS

Surface activation in a cyclotron and ion implantation techniques are used to render commercially available vascular stents radioactive. beta-Particle-emitting stents, most commonly 32P, were employed because of their short half-life (14.3 days) and limited range of tissue penetration (3-4 mm). The function and vascular response to these 32P radioactive stents with varying activities (range 0.14-23 microCi) was evaluated in several animal models of arterial injury and restenosis.

RESULTS

In porcine iliac arteries, beta-particle-emitting stents with an initial activity of 0.14 microCi reduced neointimal formation 37% at 28 days after implant. On histology, the neointima consisted of smooth muscle cells and a proteoglycan-rich matrix. Scanning electron microscopy demonstrated complete endothelialization of the stent. beta-Particle-emitting stents with an initial activity of 3-23 microCi inhibited neointimal smooth muscle cell proliferation at 28 days in a porcine coronary restenosis model. The neointima within these high-activity stents consisted of fibrin, erythrocytes, and only rare smooth muscle cells. Studies with 1-year follow-up after implantation of a radioactive stent with a composition of gamma- and beta-particle-emitting radionuclides 55,56,57Co, 52Mg, and 55Fe and an initial activity of 17.5 microCi demonstrated almost complete inhibition of neointimal proliferation in a rabbit model.

CONCLUSION

Endovascular irradiation delivered via a radioactive stent reduces neointimal formation and improves luminal patency without increasing the risk for stent thrombosis in experimental models of restenosis. The optimal radiation dose is unknown. At stent activities >3 microCi of 32P, the inhibition of neointimal formation is due to direct radiation affects on proliferating smooth muscle cells. At ultra-low activities (0.14 microCi), beta-particle irradiation reduces neointimal formation possibly by impairing cell proliferation or migration. This novel therapy may have a significant impact on preventing stent restenosis, and requires further investigation.