Balloon-expandable Stent Implantation Research Articles

Percutaneous Balloon-Expandable Stent Implantation to Treat Transverse Aortic Arch Obstruction: Medium- to Long-Term Outcomes of a Retrospective Multicenter Study.

Transverse aortic arch obstruction is a challenging lesion for which stent implantation provides a potentially important alternate therapy. The objectives were to evaluate the technical, procedural, and medium-to-long-term clinical outcomes of percutaneous stent implantation of transverse aortic arch obstruction. This is a retrospective, multicenter study of transverse aortic arch stent implantation. Univariable and multivariable analyses were performed. Index catheterization included 187 stent implants in 146 patients. The median age is 14.3 years (interquartile range, 9.3-19), weight is 53 kg (30-69), and follow-up is 53 months (12-120). The most common stent design was open cell (n=90, 48%). Stents overlapped 142 arch vessels (37 carotid arteries) in 118 (81%) cases. Technical and procedural success rates were 100% and 88%, respectively. Lower weight (P=0.018), body surface area (P=0.013), and minimum-to-descending aortic diameter ratio (P<0.001) were associated with higher baseline aortic gradient. The residual gradient was inversely associated with implant and final dilation diameters (P<0.001). The combined incidence of aortic injury and stent-related complications was 14%. There were no reports of abnormal brain scans or stroke. Blood pressure cuff gradient, echocardiographic arch velocity, and hypertension rates improved within 1-year follow-up with increased antihypertensive medication use. Reintervention was reported in 60 (41%) patients at a median of 84 (22-148) months to first reintervention. On multivariable logistic regression, residual aortic gradient >10 mm Hg was associated with increased odds of reintervention at all time points when controlling for each final dilation diameter, weight, and minimum-to-descending aortic diameter ratio. Transverse aortic arch stent implantation has high rates of technical, procedural, and medium-to-long-term clinical success. Aortic gradient >10 mm Hg is associated with increased odds of reintervention at 1-year and most recent follow-ups. Open cell stent design was frequently used for its advantages in conformability, perfusion of arch vessels, low fracture rate, and the ability to perform effective angioplasty of side cells.

Midterm Outcomes of Antegrade In Situ Laser Fenestration of Polyester Endografts for Urgent Treatment of Aortic Pathologies Involving the Visceral and Renal Arteries

Aortic endografting and antegrade in situ laser fenestration of visceral arteries (LFEVAR) may be considered as an alternative to open surgery for repair of emergent complex abdominal aortic aneurysms (AAA) in fragile patients. The aim of this article is to evaluate the midterm results of LFEVAR performed with polyester endografts. From August 2015 to December 2020, all consecutive LFEVAR performed for non-deferrable treatment of complex AAA were analysed. Polyester endografts were deployed and subsequently fenestrated using an atherectomy laser probe; the fenestrations were enlarged using cutting and semicompliant balloons before implantation of balloon expandable bridging stents into the target vessels. Prospectively collected midterm survival, patency, and re-intervention rates were analysed. Forty four procedures were performed for 11 T1a endoleaks, five thoracoabdominal aneurysms, 20 pararenal aneurysms, four segmental renal artery (RA) preservations, three anastomotic aneurysms, and one aortic dissection. One hundred and eight laser fenestrations were performed (26 for the superior mesenteric artery [SMA], 13 for the coeliac trunk, 33 and 31 for the right and left RA, respectively). Median ischaemia duration was 7, 48, 48, and 45 minutes, respectively. Technical success rate was 97%, with no open surgical conversions. The 30 day mortality was 4.5% (n = 2). No spinal cord events were observed nor early stent related complications. Kaplan-Meier overall survival at two years was 73%, the aortic related re-intervention free survival was 70%, and the stent related re-intervention free survival was 90.6%. Four target vessel thromboses were detected, of which three were rescued. Three type IIIC endoleaks, one RA false aneurysm, and one SMA stenosis, required re-intervention during a median follow up of 24.7 months. Antegrade LFEVAR is feasible, safe, and provides satisfactory early and midterm outcomes for non-deferrable treatment of aortic pathologies involving the visceral segment. Long term data are mandatory to confirm the usefulness of this promising off label technique.

Balloon-expandable stents for native coarctation of the aorta in children and adolescents.

Although balloon-expandable stent implantation for native aortic coarctation is a preferred method in the adolescent age group, there are insufficient data about indications for and the efficacy of the procedure in a younger age group. The aim of this study was to compare and evaluate the data of young pediatric and adolescent patients who underwent balloon-expandable stent implantation because of native aortic coarctation. The retrospective analysis included the demographic characteristics and data related to the procedure and follow-up of patients who underwent stent implantation for native aortic coarctation between August 2010 and November 2017. Patients with re-coarctation were excluded from the study. The patients were separated into 2 groups as the adolescent group (Group I: 10-18 years) and the pediatric group (Group II: ≤ 9.9 years). Group-I comprised of 18 patients and Group-II, 32 patients. Covered stent was implanted to 32 (73%) patients and uncovered stent to 12 (27%) patients. The procedural success rate was 100%. Following stent implantation, peak systolic gradient decreased significantly in both groups (P < .0001) (Group-I: from 35.9 ± 16.6 mm Hg-2.2 ± 3.4 mm Hg, Group II: from 34 ± 13.3 mm Hg-3 ± 4.09 mm Hg). Complications developed in 3 patients, and all in Group I. Femoral hematoma developed in 1 patient, balloon rupture occurred during the procedure in 1 patient, and there was temporary loss of pulse in 1 patient. All the complications were treated successfully. All the patients were taking anti-hypertensive drugs before intervention and during the mean 23-month follow-up period (range, 2-84 months), hypertension recovered in 35 (80%) patients and drugs were terminated. Stent implantation for aortic coarctation in the pediatric age group may provide pleasing results, reducing the coarctation gradient, providing effective dilatation in the lesion area and eliminating hypertension.

Long term follow-up after balloon expandable covered stents implantation for management of transcatheter aortic valve replacement related vascular access complications.

To report the experience of a high-volume center with balloon-expandable (BE) stents implantation to manage vascular complications after transcatheter aortic valve replacement (TAVR). Despite increased operator experience and better devices, vascular complications after TAVR are still a major issue and covered stent implantation is often required. We retrospectively collected baseline and procedural data about 78 consecutive patients who underwent BE stent implantation to manage a vascular complication after transfemoral TAVR. Primary endpoints were technical success, incidence of new-onset claudication and need for vascular interventions during long-term follow-up. Secondary endpoints included length of hospitalization, in-hospital and 30-day mortality, and major postoperative complications. BE stents implantation to manage vascular complications after TAVR was successfully performed in 96.2% of the cases, with bailout surgery required in two cases. One patient suffered in-hospital death. Predischarge Doppler Ultrasound revealed no cases of in-stent occlusion or fracture. At a median follow-up of 429 days (interquartile range, 89-994 days), no cases of symptomatic leg ischemia were reported and only one patient experienced new-onset claudication. Our experience showed good periprocedural and long-term results of BE covered stent implantation to manage vascular complication after TAVR. Their great radial outward force may guarantee effective hemostasis without necessarily being associated with stent deformation/fracture resulting in restenosis or further interventions. More research is needed to define the role of BE covered stents in this setting.

Endovascular Treatment of Subclavian Artery Stenosis: Single-Center Experience

Introduction The aetiology of subclavian artery stenosis can be very different, but typically the most common form is due to atherosclerotic disease. Interventional treatment is generally indicated for upper limb ischemia, vertebrobasilar symptoms and subclavian steal syndrome, coronary steal syndrome. Endovascular stenting is preferred over surgery because of its high success rate, less invasive nature, and minimal complication rate. In this study the characteristics of patients treated endovascularly due to subclavian artery stenosis in our centre and their procedural details will be examined. Methods: We retrospectively analyzed patients with subclavian artery stenosis treated by endovascular techniques in our centre between January 2019 and January 2021. Result Twelve (80%) of 15 patients with stenotic subclavian arteries were successfully treated with endovascular techniques. In 3 patients, the procedure was terminated with failure.The mean age of the patients was 64.66 years old and 3(20%) of the patients were female. All of the patients were receiving antihypertensive treatment with the diagnosis of hypertension, and 4 (26.66%) patients had Diabetes mellitus, 13 (86.66%) patients had hyperlipidemia, 13 (86.66%) patients had coronary artery disease. In 2 patients, the lesion was diagnosed in the right subclavian artery. In 7 patients, the procedure was performed with the telescopic method from a transfemoral approach. In 5 patients, the transradial approach was used. In 3 patients, the procedure was performed directly over the transbrachial approach. Balloon expandable stent implantation was performed in 10 (66.66%) patients at the end of the procedure, and self-expandable stent implantation was performed in 1 patient. Conclusion In conclusion, signs and symptoms can be managed effectively with endovascular techniques in patients with significant subclavian artery disease. In this study, we shared our real-life data on subclavian artery endovascular treatment.

Balloon expandable stent implantation for superior vena caval obstruction following surgical repair of partial anomalous pulmonary venous drainage: Medium term follow-up

BackgroundObstruction to the superior vena cava (SVC) is a well described complication of surgical repair of right sided partial anomalous pulmonary venous drainage. MethodsReview of the surgical, catheter and cardiology databases at three institutions over 10 year period. ResultsSeven patients were identified with SVC obstruction at a median of 0.6 years (range 0.3–3.3) after surgical repair of right sided anomalous pulmonary venous drainage to the SVC or SVC/right atrial junction. All were symptomatic and had undergone either standard repair or the ‘Warden procedure’. Bare metal stents were implanted percutaneously in all patients via the right femoral vein. Mean pullback pressure gradients fell from a median of 11 mmHg (Range 7–20) to 1 mmHg (Range 0–2 mmHg) and minimum caval diameter increased from a median of 5 mm (Range 2.4–6) to 13 mm (Range 7.6–16). At median follow-up interval of 9.1 years (5.8–10) all remain well although one patient had developed stent fractures necessitating further stent implantation and three patients required further balloon dilation of the stent. All remain in sinus rhythm with no PR interval prolongation. ConclusionStent implantation offers effective medium-term relief of acquired superior vena caval obstruction after surgical repair of right sided anomalous pulmonary venous repair.

Midterm to long-term safety and efficacy of self-expandable nitinol stent implantation for coarctation of aorta in adults.

Endovascular treatment of coarctation of aorta (CoA) by self-expandable Nitinol stents is one of the recognized treatment methods and may be an alternative to surgery or balloon-expandable stent implantation for CoA but there is little information about midterm to long term results of self-expandable stents. Sixty-two patients with CoA (40 men), with a mean age of 30.7 ± 11 years, (range 17-63 years) underwent stent implantation with Optimed self-expandable Nitinol stents between 2005 and 2014. Successful outcome was defined as peak systolic pressure gradient ≤20 mmHg after stent implantation. The patients were followed-up clinically and by echocardiography and in patients, in whom there was suspicion of recoarctation, CT angiography or recatheterization was performed. 65 stents were successfully implanted in all 62 patients. Peak systolic pressure gradient decreased from mean 62.4 ± 18 mmHg (range 35-100 mmHg) to mean 2.8 ± 5 mmHg (range 0-15 mmHg; P < 0.001). Stent displacement occurred in 3 patients during the procedure. These were managed successfully by an overlapping second stent. None of the patients had major complications such as aortic dissection, rupture, or vascular access problems. In follow up, only three patients had recoarctation, and two of these were managed successfully by balloon redilation or further stenting 16 and 18 months after the first procedure and one patient refused reintervention. There were two deaths, unrelated to the procedure, 12 and 78 months after the initial intervention. Follow-up of a mean of 45.5 ± 17 months (range 12-105 months) demonstrated no evidence of aneurysm formation or stent fracture. Self-expandable nitinol stents for the treatment of native and recurrent CoA is safe and has good efficacy with acceptable midterm to long-term outcome.

İliyak Arter Stentlemenin Nadir Bir Komplikasyonu: Erken Dönem Stent Kırılmasına Bağlı Akut Alt Ekstremite İskemisi

A 57 years old male patient with Fontain class 2b symptoms is diagnosed with iliac artery stenosis and was treated with a balloon expandable stent implantation in his right common iliac artery. After 10 days of the intervention he came to our hospitals emergency department with complaints of pain and coldness in his right leg. Arteriography showed stent fracture, in the right iliac artery. Rupture and thrombosis in the iliac artery distal to the stent was also detected. We attempted to implant a stent in the previously implanted stent but the leakage due to rupture still present. Therefore a aorto biiliac stent graft was implanted with success.

Multi-modality imaging for stent edge assessment

Optical coherence tomography (OCT) has a sufficiently high resolution to allow assessment of stent edge dissection (ED). The aims of the present study were as follows: (1) evaluation of the frequency of stent ED using OCT; (2) comparison of stent ED detection rates obtained using angiography, intravascular ultrasound (IVUS), and OCT; and (3) IVUS-Virtual Histology (IVUS-VH) evaluation of plaque composition at the site of stent EDs detected by OCT after percutaneous coronary intervention (PCI). Fifty-eight consecutive patients (59 lesions, 100 stent edges) who underwent balloon-expandable stent implantation and post-stent assessment with OCT and IVUS-VH were included. OCT revealed stent ED in 24.0 % (24 of 100) of stent edges after PCI with a balloon-expandable stent. In contrast, ED was detected in only 3.0 % (3 of 100) of stent edges using angiography and 4.0 % (4 of 100) of stent edges using IVUS. Plaque evaluation using IVUS-VH showed that the percent necrotic core (21.2 ± 8.3 vs. 13.4 ± 10.7 %, p = 0.001) and absolute dense calcium (2.9 ± 2.4 vs. 1.3 ± 2.2 mm(3), p = 0.0104) and dense calcium (13.8 ± 9.3 vs. 5.4 ± 5.8 %, p < 0.001) volumes were greater in the ED group than in the non-ED group. Thus, OCT is superior to conventional coronary angiography and IVUS in the identification of stent ED. In addition, the plaque composition at the ED site is characterized by a necrotic core and greater dense calcium levels than those observed at the non-ED site.

Experimental investigation of the stent–artery interaction

It is well acknowledged that stent implantation causes abnormal stretch and strains on the arterial wall, which contribute to the formation and progression of restenosis. However, the experimental characterization of the strain field on the stented vessel is scant. In this work, the balloon-expandable stent implantation inside an artery analogue was captured through two high-speed CCD cameras. The surface strain maps on the stented tube were quantified with a 3-D digital image correlation technique. The strain history at one specific reference point illustrated three stenting phases, including balloon inflation, pressurization and deflation. The surface strain distributions along one axial path were obtained at various time points to demonstrate the stent–vessel interactions. The radial wall thickness reduction history was used to evaluate the pressure–diameter relationship for the balloon. Results indicated that the expansion process of the balloon was significantly altered by the external loadings from both the stent and artery analogue. In addition, the repeatability of the stenting experiments was demonstrated through two tests with a change of 5% in the stent-induced maximum first principal strain. Moreover, a computational model of the stenting procedure was developed to recapture the stenting experiments. Comparison between experiments and simulation showed a difference of 7.17% in the first principal strain averaged over the high strain area. This indicated the validation of the computational framework, which can be used to investigate the strain or stress field throughout the computational domain, a feature that is not affected by experimental techniques.

Treatment of type I endoleak in an iliac aneurysm with balloon expandable palmaz stent

Endovascular exclusion of the peripheral arterial aneurysms with covered stent grafts have been used to decrease the operative morbidity and mortality in comorbid old patients. However, endoleaks remain a problem. The authors present a case of left common iliac artery aneurysm, which was treated by endovascular therapy. Initially, internal iliac artery was occluded with coil embolization to prevent type II endoleak. A covered self-expandable stent was used for exclusion of the aneurysm. A proximal perigraft leak was detected in control contrast injection. Palmaz balloon expandable stent was used for treatment of proximal perigraft leak. The control angiography showed complete exclusion of the aneurysm and no perigraft leak was detected in the aneurysm sac. Proximal balloon expandable stent implantation as an addition to covered stent in short and angulated necked aneurysms is technically feasible, and this technique provide a good treatment method for proximal perigraft leak.

Balloon expandable stent implantation for native and recurrent coarctation of the aorta—prospective computed tomography assessment of stent integrity, aneurysm formation and stenosis relief

Balloon expandable stent implantation for native and recurrent coarctation of the aorta—prospective computed tomography assessment of stent integrity, aneurysm formation and stenosis relief

Safety and feasibility of balloon-expandable stent implantation for the treatment of type I endoleaks following endovascular aortic abdominal aneurysm repair

The occurrence of type I endoleaks represent an ominous sign after endovascular aneurysms repair (EVAR). We report our experience using balloon-expandable stents (BES) for the treatment of proximal Type I endoleaks at five high-volume hospitals in Argentina. Of 1,395 patients who underwent EVAR, we retrospectively collected data of 29 (2%) consecutive patients who underwent additional BES to repair proximal type I endoleaks. The mean age was 75.8 years old (range 63-87) and 93% were male. A hostile anatomy was found in 89.6% of the cases. BES oversize (balloon/neck diameter ration ≥ 30%) was frequent (69%); whereas, BES/prosthesis diameter ratio was less than 1 in 79% of the cases. Complete and partial sealing was obtained 72 and 28% of the cases, respectively. There were no immediate or late surgical conversion or major complications related with stent implantation. At a median time follow-up of 14.9 months (25-75% interquartiles: 4.5-17.5 months), there were no cardiovascular deaths, evidence of aneurysm sac enlargement or need for re-intervention. Our preliminary results suggest that BES implantation for the treatment of proximal type I endoleaks is feasible and safe with favourable mid-term results and may preclude the need for surgical conversion.

Balloon expandable stent implantation for native and recurrent coarctation of the aorta—prospective computed tomography assessment of stent integrity, aneurysm formation and stenosis relief

BackgroundStenting for aortic coarctation is known to be effective in the medium term. Aneurysm formation following stent implantation is a recognised complication. However, data regarding aortic wall injury and stent...

Percutaneous Transluminal Angioplasty (PTA) Alone versus PTA with Balloon-expandable Stent Placement for Short-segment Femoropopliteal Artery Disease: A Metaanalysis of Randomized Trials

To evaluate and compare the results of percutaneous transluminal angioplasty (PTA) and stent placement to treat femoropopliteal artery occlusive disease. Published data of randomized clinical trials comparing the results of PTA and stent placement for femoropopliteal artery occlusive disease were analyzed. Proportions were combined, and the odds ratio (OR) with its 95% CI was used as the effect size estimate. Seven studies published in 1999 or later (614 limbs in 519 patients) were included in this metaanalysis, in which 323 limbs underwent PTA and 291 limbs underwent PTA followed by balloon-expandable stent placement. In the combined results of PTA versus PTA plus stent placement, a significant difference in primary patency at 6 months (OR, 0.47; 95% CI, 0.27-0.84; P < .05) was found, but no significant difference could be found in primary patency at 12 months (OR, 1.27; 95% CI, 0.87-1.86; P > .05) or 24 months (OR, 1.22; 95% CI, 0.81-1.82; P > .05) or in secondary patency at 12 months (OR, 1.34; 95% CI, 0.78-2.30; P > .05). In the treatment of femoropopliteal artery occlusive disease (< or =10 cm), higher primary patency rates can be expected at 6 months with PTA followed by implantation of balloon-expandable stents versus PTA alone, but PTA with stent placement does not produce better long-term primary results and secondary patency rates than PTA alone.

Comparison of the vascular responses to balloon-expandable stenting in the coronary and peripheral circulations: Long-term results in an animal model using the TriMaxx stent

The clinical results after stenting in the coronary and peripheral circulations are vastly different. Possible explanations for this discrepancy include generally longer and more complex lesions in the periphery, variable vascular responses to injury according to anatomic location, disparate blood flow rates, and impedance in coronary vs skeletal smooth muscle beds, or phenotypic differences in neointimal hyperplasia and remodeling. This study examined the long-term results (6 months) after implantation of phosphorylcholine-coated balloon-expandable stents in a porcine model of experimental in-stent coronary and peripheral arterial restenosis. Forty-eight stainless steel-tantalum-stainless steel composite balloon-expandable stents coated with phosphorylcholine (TriMaxx stent, Abbott Laboratories, Abbott Park, Ill) were implanted in the coronary (3.0 x 15 mm) or larger femoral arteries (4.0 x 38 mm) of Yorkshire crossbred swine to achieve a 1.1:1 stent-to-artery ratio. After 28, 90, or 180 days, the arteries were excised, perfusion-fixed at 100 mm Hg, sectioned, and stained with hematoxylin and eosin for morphometric evaluation. One animal did not survive to euthanasia; all arteries in surviving animals were patent. No significant differences were found in mean injury or inflammation scores among the groups or time points. The larger femoral arteries generated more neointimal area over time than the coronary arteries. The neointimal area in coronary arteries was 2.76 +/- 0.71, 1.75 +/- 0.42, and 1.83 +/- 0.19 mm(2) at 28, 90, and 180 days, respectively, and 5.20 +/- 0.97, 3.11 +/- 0.53, and 5.10 +/- 0.80 mm(2) in the femoral arteries (P < .05 coronary vs femoral at 180 days). This led to statistically significantly increased percent area stenosis at 180 days (coronary 27% +/- 4% vs femoral 45% +/- 5%; P < .05). The vascular response to balloon-expandable stenting in the coronary and peripheral circulations is different. After 6 months, neointimal hyperplasia and stent-induced stenosis were increased in peripheral porcine arteries compared with coronary arteries.

Aortoiliac Kissing Stents:Long-term Results and Analysis of Risk Factors Affecting Patency

To present the early and long-term results of aortoiliac kissing stents implantation and evaluate the risk factors affecting patency. The data were retrospectively reviewed on 68 patients (64 men; mean age 55+/-11, range 32-77) who underwent kissing stents implantation during a 12-year period. The majority of patients (64, 94%) had claudication; 4 patients had rest pain. All were smokers. There were bilateral or unilateral stenoses in 42 (62%) patients, and unilateral occlusion and contralateral stenosis in 26 (38%). Lesions were treated with simultaneous implantation of self-expanding (n=52) or balloon-expandable (n=16) stents. After the procedure, patency was determined with Doppler ultrasonography or angiography at 1, 3, 6, and 12 months and annually thereafter. Primary, assisted primary, and secondary patency rates were calculated with Kaplan-Meier analysis on an intention-to-treat basis, and risk factors affecting the patency rates were determined with the Cox regression analysis. All procedures were technically and clinically successful. Complications occurred in 12%, but none required surgery. The follow-up period was 35+/-31 months. Primary, assisted primary, and secondary patency rates, respectively, were 76%, 90%, and 94% at 1 year; 63%, 86%, and 92% at 3 years; and 63%, 64%, and 81% at 5 years. In multivariate analysis, age <50 years and presence of iliac occlusion were identified as risk factors for reduced primary and assisted primary patency; a crossed configuration of kissing stents was identified as a risk factor for reduced primary patency. Implantation of kissing stents is a safe and effective alternative in the treatment of aortoiliac obstructions. However, overall primary and assisted primary patency rates are inferior to those reported for surgery. Long-term patency comparable to surgery may be obtained in patients >50 years and in those without an iliac occlusion, particularly if a favorable stent configuration is achieved.

Self- and balloon-expandable stent implantation for severe native coarctation of aorta in adults

Background Balloon angioplasty for native coarctation of the aorta (CoA) in adults, though promising, is sometimes limited by significant residual gradient (>20 mm Hg). Few studies available have reported on use of balloon-expandable stents in such a situation. We evaluated the use of self- and balloon-expandable stents in patients with suboptimal response to balloon angioplasty (BA). Methods Twenty-one hypertensive patients (age, 18 to 61 years; mean, 28.6 ± 11.2 years) with native CoA and in whom results of BA were suboptimal (ie, residual peak systolic gradient [PSG] >20 mm Hg) underwent stent implantation. Balloon-expandable Palmaz stents were implanted in 5 patients (group A) and self-expandable nitinol aortic stents in the remaining 16 patients (group B). Results In group A, PSG decreased from 62.8 ± 10.6 (53 to 80) mm Hg to 28.1 ± 6.3 (22 to 39) mm Hg after BA. Systolic gradient further decreased to 8.3 ± 3.9 (2 to 16) mm Hg ( P < .001) after implantation of the balloon-expandable Palmaz stent. In group B, PSG decreased from 70.2 ± 24.6 (40 to 110) mm Hg to 28.4 ± 9.8 (22 to 42) mm Hg after BA and further reduced to 9.0 ± 5.5 (4 to 16) mm Hg ( P < .001). One of these patients had a nitinol self-expandable stent implanted after a Palmaz stent embolized immediately after deployment. Nitinol stents were easier to deploy and conformed better to aortic anatomy compared with balloon-expandable stents. In group A, the diameter of the coarcted segment increased from 3.8 ± 0.8 mm to 13.3 ± 0.8 mm ( P < .001) after stent implantation and in group B it increased from 4.5 ± 1.1 mm to 14.1 ± 2.1 mm ( P < .001). There was no significant difference between the two groups in the PSG and diameter of the coarcted segment before and after stent implantation. With the exception of one case, in which a Palmaz stent embolized, there was no other complication in our series. On follow-up of 12 to 71 months (mean, 40.7 ± 5.8 months) all the implanted stents remained in their original position and none showed evidence of fracture. Improvement in hypertension was seen in 20 of 21(95.2%) of the patients. On recatheterization and angiography 1.2 ± 0.6 years after implantation in 19 patients, one patient showed an increase in PSG to 27 mm Hg across the nitinol stent and underwent successful redilation. No increase in gradient was seen in other patients. Beneficial late remodeling was seen in 10 of 14(71.4%) of patients restudied after implantation of self-expandable stent. None of the patients showed aneurysm formation. Conclusions Stent implantation is safe and effective in improving suboptimal results after BA for CoA. Self-expandable stents were easier to implant, adapted better to the wall of the aorta, and in most patients had similar efficacy in reducing coarctation as balloon-expandable stents.

Impact of moderate lesion calcium on mechanisms of coronary stenting as assessed with three-dimensional intravascular ultrasound in vivo

Axial plaque redistribution is an important mechanism of lumen enlargement after stenting of noncalcified lesions. To assess effects of lesion calcification on mechanisms of coronary stenting, we analyzed 55 lesions with noncircumferential calcification with 3-dimensional intravascular ultrasound (IVUS) (standard qualitative and quantitative analyses) before and after implantation of balloon-expandable stents. Thirty-two plaques (58%) showed arcs of calcium <120° of vessel circumference (group A), whereas 23 lesions (42%) contained arcs of calcium ≥120° of vessel circumference (group B). In the entire cohort of 55 lesions, as well as groups A and B, which were studied separately, both single-slice IVUS analysis (performed at minimum lumen site before intervention) and mean stented segment IVUS analysis showed an increase in lumen and vessel area and a decrease in plaque area (p <0.001). The magnitude of lumen and vessel increase and of plaque decrease was similar in both groups. Group A lesions showed significant plaque extrusion into the distal reference segment that was not observed in group B (increase in plaque area of 1.3 ± 1.9 vs 0.1 ± 2.0 mm 2, p <0.04). Stenting did not alter plaque area of the proximal reference segment in either group. In addition, there was an increase in vessel area of the distal reference of both groups, indicating that stent-induced vessel expansion observed within the lesion also affected the distal reference. Thus, longitudinal plaque redistribution and vessel expansion contribute to increased lumen dimensions during stenting of lesions with varying amounts of calcium; however, marked plaque extrusion was found only in lesions with a calcium arc of <120°.

Descending aortic doppler velocities after balloon-expandable stent implantation for coarctation of the aorta: are they related to pressure changes by the Bernoulli Equation?

Descending aortic doppler velocities after balloon-expandable stent implantation for coarctation of the aorta: are they related to pressure changes by the Bernoulli Equation?