Larger Luminal Diameter Research Articles

Drosophila renal stem cells enhance fitness by delayed remodeling of adult Malpighian tubules.

Drosophila renal stem cells (RSCs) contradict the common expectation that stem cells maintain tissue homeostasis. RSCs are abundant, quiescent, and confined to the peri-ureter region of the kidney-like Malpighian tubules (MTs). Although derived during pupation-like intestinal stem cells, RSCs initially remodel the larval MTs only near the intestinal junction. However, following adult injury to the ureter by xanthine stones, RSCs remodel the damaged region in a similar manner. Thus, RSCs represent stem cells encoding a developmental redesign. The remodeled tubules have a larger luminal diameter and shorter brush border, changes linked to enhanced stone resistance. However, RSC-mediated modifications also raise salt sensitivity and reduce fecundity. Our results suggest that RSCs arose by arresting developmental progenitors to preserve larval physiology until a time in adulthood when it becomes advantageous to complete the development by RSC activation.

Direct aspiration thrombectomy experience with the SOFIA 6F catheter in acute ischemic stroke.

As the SOFIA (Soft torqueable catheter Optimized For Intracranial Access) 6F catheter has a large luminal diameter, it can be used as an aspiration catheter. Furthermore, it may function as an intermediate catheter when a stent retriever is required. We aimed to evaluate the usefulness of the SOFIA 6F catheter in mechanical thrombectomy with the direct aspiration first pass technique. Patients who had undergone mechanical thrombectomy (September 2017-January 2019) using the SOFIA 6F catheter in two centers were retrospectively analyzed. We used the thrombolysis in cerebral infarction (TICI) scale to evaluate the success of recanalization. National Institutes of Health Stroke Scale scores on admission and discharge were used together with the modified Rankin Scale (mRS) scores at 90days. In 132 (89.1%) of the 148 cases, the thrombus was in the anterior system. The SOFIA 6F catheter reached the thrombus site in 130 (87.8%) cases. The rate of successful recanalization (TICI ≥ 2b) was 89.1%. The targeted clinical outcome (mRS score ≤ 2 at 90th days) was achieved in 49.3% of cases. Symptomatic intracranial hemorrhage occurred in 5.4%. The rate of emboli to new vascular territories was 5.4%. Mortality was 14.1%. In the majority of our cases, the SOFIA 6F catheter provided effective and rapid recanalization with aspiration thrombectomy.

Development and in vivo Assessment of a Rapidly Collapsible Anastomotic Guide for Use in Anastomosis of the Small Intestine: A Pilot Study Using a Swine Model.

Various conditions in human and veterinary medicine require intestinal resection and anastomosis, and complications from these procedures are frequent. A rapidly collapsible anastomotic guide was developed for small intestinal end-to-end anastomosis and was investigated in order to assess its utility to improve the anastomotic process and to potentially reduce complication rates. A complex manufacturing method for building a polymeric device was established utilizing biocompatible and biodegradable polyvinylpyrrolidone and polyurethane. This combination of polymers would result in rapid collapse of the material. The guide was designed as a hollow cylinder composed of overlaying shingles that separate following exposure to moisture. An in vivo study was performed using commercial pigs, with each pig receiving one standard handsewn anastomosis and one guide-facilitated anastomosis. Pigs were sacrificed after 13 days, at which time burst pressure, maximum luminal diameter, and presence of adhesions were assessed. Burst pressures were not statistically different between treatment groups, but in vivo anastomoses performed with the guide withstood 10% greater luminal burst pressure and maintained 17% larger luminal diameter than those performed using the standard handsewn technique alone. Surgeons commented that the addition of a guide eased the performance of the anastomosis. Hence, a rapidly collapsible anastomotic guide may be beneficial to the performance of intestinal anastomosis.

Measurement of the Internal Carotid Artery Cross-Sectional Area: Systematic Differences Depending on Grayscale, Power Doppler, and Color Doppler Techniques.

To determine how measurements of the internal carotid artery (ICA) cross-sectional area will differ systematically when obtained by grayscale, color Doppler, and power Doppler imaging. A total of 451 patients had greater than 40% diameter stenosis in at least a single ICA. Anteroposterior and transverse luminal diameters were measured in 609 arteries on grayscale, color, and power Doppler transverse images of the carotid bulb and proximal and distal ICAs. Cross-sectional areas were calculated and compared by a repeated-measures analysis of variance model to assess for significant differences. Mean ICA cross-sectional areas ± SDs as measured by grayscale, power Doppler, and color Doppler imaging were 122 ± 81, 122 ± 79, and 125 ± 79 mm2 , respectively. The mean ICA area estimated by color Doppler imaging was significantly greater than that estimated by power Doppler imaging (P < .0001) and grayscale imaging (P = .02). Area estimates on grayscale and power Doppler images were not significantly different (P = .99). After accounting for the correlation of repeated measurements within single vessels, color Doppler estimates of the luminal area were on average 3.44 and 9.5 mm2 greater than grayscale and power Doppler estimates. Relative cross-sectional area estimates were on average 9.4% greater with color Doppler imaging at smaller luminal diameters (<60 mm2 ) compared with larger luminal diameters. Measurements of the ICA cross-sectional area by color Doppler imaging were significantly greater than those obtained by power Doppler or grayscale imaging. This difference should be considered when stenosis estimates are confirmed or graded by luminal measurements.

Predictors of no-Reflow in Patients with ST-Segment Elevation Acute Myocardial Infarction after Primary Percutaneous Coronary Intervention

Background: Primary percutaneous coronary intervention (PCI) is the preferred method of ST-segment elevation acute myocardial infarction (STEMI) management but no-reflow phenomenon is one of its major complications that affects patient's outcome. Objective: Identification of possible clinical, angiographic and procedural predictors for no-reflow in patients with AMI after primary percutaneous coronary intervention (PCI). Methods: A total of hundred patients with AMI who had been treated by primary PCI at the National heart institute (NHI) and cardiology department, Menoufia University hospital were enrolled in this study, according to thrombolysis in myocardial infarction (TIMI) flow grade, patients were divided into a reflow group (TIMI 3) and a no-reflow group (TIMI ≤ 2). The clinical, angiographic and procedural data were compared between both groups. Discussion: Sixteen patients (16%) developed no-reflow phenomenon after primary PCI. Statistical analysis showed that time from onset to reperfusion, low initial TIMI flow grade, high thrombus burden, long lesion length and large reference luminal diameter were correlated with no-reflow (P < 0.05 for all) and were considered to be independent predictors of no-reflow. Conclusion: The occurrence of no-reflow after primary PCI for acute myocardial infarction can be predicted by certain clinical, angiographic and procedural features.

Long-term function and optimization of mouse and human islet transplantation in the subcutaneous device-less site

ABSTRACTClinical islet transplantation has routinely been demonstrated to be an efficacious means of restoring glycemic control in select patients with autoimmune diabetes. Notwithstanding marked progress and improvements, the broad-spectrum application of this treatment option is restricted by the complications associated with intrahepatic portal cellular infusion and the scarcity of human donor pancreata. Recent progress in stem cell biology has demonstrated that the potential to expand new β cells for clinical transplantation is now a reality. As such, research focus is being directed toward optimizing safe extrahepatic transplant sites to house future alternative β cell sources for clinical use. The present study expands on our previous development of a prevascularized subcutaneous device-less (DL) technique for cellular transplantation, by demonstrating long-term (>365 d) durable syngeneic murine islet graft function. Furthermore, histological analysis of tissue specimens collected immediately post-DL site creation and acutely post-human islet transplantation demonstrates that this technique results in close apposition of the neovascularized collagen to the transplanted cells without dead space, thereby avoiding hypoxic luminal dead-space. Murine islets transplanted into the DL site created by a larger luminal diameter (6-Fr.) (n = 11), reversed diabetes to the similar capacity as our standard DL method (5-Fr.)(n = 9). Furthermore, glucose tolerance testing did not differ between these 2 transplant groups (p > 0 .05). Taken together, this further refinement of the DL transplant approach facilitates a simplistic means of islet infusion, increases the transplant volume capacity and may provide an effective microenvironment to house future alternative β cell sources.

Abstract O.58: Medium-term Outcomes of Coronary Artery Aneurysms after Kawasaki Disease: A Study from the North American Kawasaki Disease Registry

Background: One of the main impediments to conceiving and planning studies in children with coronary artery aneurysms (CAA) after Kawasaki disease (KD) is the lack of normative data regarding the prevalence of outcomes over time and risk factors. Methods: The North American Kawasaki Disease Registry was used to determine the prevalence of multiple clinically important outcomes of CAA after KD. All analyses were stratified by severity of CAA (small CAA with z-score = 2.5-5, medium with z-score = 5-10 and giant with z-score &gt;10). All analyses were performed using non-parametric survival analysis. Results: n=621 patients submitted to the Registry had complete follow-up data and were included in the analysis (280 [45%] small CAA, 139 [22%] medium and 202 [33%] giant). Time-related freedom from multiple outcomes stratified by type of CAA are reported in the Table. Reduction in z-scores was strongly associated with the initial size of the lesion, with smaller lesions being more likely to decrease to a normal dimension over time. Thrombosis and stenosis were infrequent in patients without giant CAA. For those patients with giant CAA, the risk of thrombosis, myocardial infarction, angiographically-confirmed stenosis and revascularization was substantial and persisted up to 10 years after diagnosis. In addition to larger luminal diameter, other factors associated with increased risk of adverse outcomes included larger CAA longitudinal area and complex CAA (vs. isolated lesions). Conclusions: Only patients with giant CAA are at substantial risk of adverse clinical outcomes; future trials of pharmacological therapy targeting thrombosis and stenosis risk should focus on these patients.

Abstract T P419: Pathological Arterial Wall Correlates of Lumen-based Remodeling: Results From the Brain Arterial Remodeling Study

Background: There is paucity of data about arterial wall characteristics of the smallest and largest caliber cerebral vessels. Determining the relationship between the lumen and the wall might shed new insights into cerebral artery remodeling. Objective: To test the hypotheses that arteries with larger luminal diameters have a thinner wall and that arteries with the smallest lumina have thicker walls. Methods: Cross-sectional segments from large arteries (N=1392) were obtained from the circle of Willis in 196 autopsied brains (mean age 55 ± 17 yrs, 39% with hypertension, 15% with diabetes and 20% with dyslipidemia). Lumen diameter, stenosis percentage, and thicknesses of intima, media, and adventitia were calculated in digital microphotography after staining. Atheromas and internal elastic lamina (IEL) disruption were rated visually. Arteries were categorized into the top 5% (“dilated”) and bottom 5% (“narrowed”) of the luminal diameters, as well as an intermediate category (90% of sample as reference). We used logistic regression to obtain the odds of association (OR, 95% CI) after adjusting for demographic and vascular variables. Results: Narrowed arteries were more frequently found in men (OR 2.7, 95%CI 1.3-5.9) and with dyslipidemia (4.2, 1.6-11.1) while dilated arteries were more frequently found in women (5.6, 2.2-14.0), in smokers (2.6, 1.0-6.5) and those with prior MI (7.7, 1.2-48.7). Narrowed arteries were more likely to have atheromas (20.8, 4.8-90.3), greater luminal stenosis (per %, 1.1, 1.1-1.2), thicker vessel walls (1.3, 1.2-1.4), but thinner medias (0.9, 0.8-1.0). Conversely, larger arteries exhibited less IEL disruption (0.3, 0.1-0.9), atheromas (0.34, 0.1-0.9) and stenosis (0.8, 0.8-0.9), their walls were thinner (0.8, 0.8-0.9) but the media was thicker (1.1, 1.1-1.2). Conclusions: Narrowed cerebral arteries were more likely to have atheromas while dilated arteries had thinner walls and were more frequent in subjects with prior MI. These findings suggest that both extremes of the arterial spectrum might be differentially related with vascular disease, underscoring the need to revisit whether standard preventive measures for vascular disease are equally effective in patients harboring such disparate arterial phenotypes.

Abstract No. 417: Endovascular treatment for acute carotid blow-out with massive hemorrhage

Carotid blowout is a devastating complication in patients who have had trauma, radiation induced necrosis, recurrent head and neck malignancy, wound complications or pharyngo-cutaneous fistulas. A covered stent offers an alternative to treatment of a carotid blowout patient thought to be at high risk for surgery or carotid occlusion. Stent placement in the common carotid artery or carotid bulb is a technically challenging because of large luminal diameter and luminal caliber discrepancy between internal carotid artery and common carotid artery. We present four patients with common carotid rupture and massive bleeding who were treated with self-expanding covered stents and coiling. A 44 year old male patient presenting with profuse internal and external bleeding from a right carotid blow-out due to metastatic infiltration secondary to primary squamous cell carcinoma of the tongue. A 69 year old female patient presenting with acute bleeding from the neck with skin erosins. A 20-year-old male presenting with a stab wound to the neck. And finally a 57 year old male presenting with acute bleeding secondary to treated squamous cell carcinoma. The main indications for the type of treatment of Carotid blow-out Syndrome are location, cause, hemorrhage and angiography. Patients with negative angiography need only appropriate wound care. However patients with positive angiography are candidates for vessel occlusion, stent graft, embolization or anti-coagulation. Indications for treating Carotid blow-out syndrome complicated by dissection are also different. The placement of stent grafts or embolization in patients with active bleeding from Carotid Blow-out is a feasible and successful approach to ending acute bleeding with minimal morbidity compared to ligation of the artery. We have developed an algorithm for the proper treatment of the different types of Carotid blow-out syndrome.

Circulating levels of matrix metalloproteinase-9 and abdominal aortic pathology: from the Dallas Heart Study.

Prior reports have associated increased circulating levels of matrix metalloproteinase-9 (MMP-9), an endopeptidase active in the extracellular matrix, with the formation and rupture of aortic aneurysms, raising the possibility that MMP-9 may be a useful diagnostic or therapeutic target for aortic pathology. However, associations between MMP-9 and pathological abdominal aortic phenotypes in the general population have not been reported. In the Dallas Heart Study, a population-based sample of Dallas County residents (n = 2304), we measured MMP-9 and performed magnetic resonance imaging (MRI) of the abdominal aorta, measuring aortic compliance, plaque, wall thickness and luminal diameter. After adjustment for traditional cardiac risk factors and body size, higher MMP-9 quartiles were independently associated with higher aortic wall thickness and larger luminal diameter (p < 0.0001 for each), but not abdominal aortic plaque (p = 0.08), coronary artery calcium (p = 0.20) or the aortic luminal diameter/aortic wall thickness ratio (p = 0.37), supporting the hypothesis that therapies targeting MMP-9 may affect the abdominal aortic wall and modify aortic pathology.

Feasibility and Accuracy of Capsule Endoscopy Used as a “Retroeye” for the Diagnosis of Lesions in a Colonic Model

Purpose: Despite efforts to modify optics of the colonoscope, there remains a remarkable inability to identify all colonic pathology during colonoscopy. Some lesions can truly “hide” from current technology (proximal haustral folds, curves, etc.). The introduction of the “retroeye” accessory is an attempt to improve the yield of endoscopy in these difficult-to-see anatomical areas. Aim: To assess the feasibility of the capsule endoscopy device used as a “retroeye” to aid in identifying lesions in a colonic model in vitro. Methods: We attached a capsule endoscopy device to the side of an endoscope tip to allow simultaneous, real time, forward (conventional endoscope), and backward (capsule) views of the lumen of a simulated colon model. A colonic model from Boston Scientific was modified to allow a larger luminal diameter and exaggerated folds. A total of 50 “lesions” (pins) of different sizes (2 to 4 mm) and colors were placed (see image), at least 10 of which were truly hidden to the conventional forward viewing endoscope. An experienced endoscopist performed the procedure using only the forward view, followed by simultaneous use of the capsule real time images. Finally, real time images were read collaboratively with a fellow physician. They were unaware of the number and location of the lesions and were instructed to identify all lesions by color and location during the insertion and withdrawal phases of the procedure. The capsule monitor was placed beside the conventional endoscope monitor and projected the images in real time.FigureResults: Both with and without the capsule device attached, an average of 40 lesions (80%) were identified with the conventional forward viewing endoscope. With the aid of the capsule, up to 8 additional lesions were identified, for a cumulative detection rate as high as 96%. Lesions consistently not identified were a small lesion located on a distal haustral fold and a larger lesion found at the corner of a proximal haustral fold. Conclusion: Capsule endoscopy attached to the conventional endoscope enabled the detection of a majority of the lesions which were hidden from the forward view.

P-403 Efficacy and Safety of Primary Stenting in Takayasu Arteritis: Report of Four Cases

Background � Takayasu arteritis (TA), an inflammatory disease of unknown origin, frequently affects major aortic branch vessels and causes many symptoms, including brain and retinal ischemia and hypertension. Methods � Four patients with Takayasu arteritis (TA) underwent angioplasty and stent placement in the renal arteries due to uncontrolled hypertension. Complications of the procedure include transient bradycardia and mild hypotension, probably due to contrast agent; however, there was no major complication. Results � No restenosis has been reported in the six-month follow up of the patients with angiography. Serum creatinine levels remained unchanged in the four patients. The difference between pre- and post- interventional arterial blood pressures was measured. Mean systolic blood pressure changed from 227.5 mmHg to 150mmHg and mean diastolic pressure dropped from 122mmHg to 85 mmHg. Conclusion � The stenotic lesions in TA can be managed successfully with angioplasty and stent placement. Short-term follow up showed stenting had increased the success rate of the procedure, achieved larger luminal diameters and it seemed to decrease the incidence of restenosis. However long-term follow up is suggested to determine the restenosis rate.

Abstract 2955: Increased Luminal Diameter With Drug-eluting Versus Bare-metal Stenting Of The Piglet Ductus Arteriosus

Introduction: Maintaining ductus arteriosus (DA) patency by stent implantation may be advantageous in congenital heart disease management algorithms. Rapamycin, an immuno-suppressant drug, has anti-proliferative properties, inhibits smooth muscle cell (SMC) migration and may deter intimal hyperplasia occurring during spontaneous closure and post stent implantation of the DA. Methods: 16 Yorkshire piglets (age 7–11 days old, weight 2.2– 4.9 kg) underwent stent implantation of the DA (rapamycin-eluting (n = 8), bare metal (n = 8) stents, (3.5 mm diameter) and were sacrificed at 2, 4 and 6 weeks. Dissected DA were analyzed for SMC and extracellular matrix components (elastin, collagen and glycosaminoglycans). External diameter, wall thickness and lumen diameter were analyzed by morphometric software. DA-derived SMC were isolated and cultured for 7 days in the presence or absence of 100mM of rapamycin. Cellular proliferation rates were assessed by proliferative antigen Ki-67 detection and [ 3 H]-thymidine incorporation. Specific antibodies to elastin, collagen type I, and chondroitin sulfate-containing glycosaminoglycans were analyzed. Results: Rapamycin-eluting stents significantly inhibited neointimal formation compared with bare metal stents at 4 and 6 weeks resulting in larger luminal diameters (p&lt;0.001). The in vitro studies demonstrated rapamycin-treated cultures of the DA-derived SMC had 50% lower proliferation rates (p&lt;0.001). Conclusions : Rapamycin has anti-proliferative actions on the DA. Drug-eluting stents may be a more efficient tool for prolonging patency of the DA in neonates palliated for future correctional surgery.

In Vitro and In Vivo Biocompatibility Testing of Absorbable Metal Stents

AbstractSummary: Permanent metallic stent implants are the most frequently applied treatment option in angioplastic interventions. Here we report in vitro and in vivo characteristics of the newly developed absorbable metal stent (AMS), consisting of magnesium (Mg) with yttrium and rare earth additives, in comparison to the clinically applied steel stent (316L). Viability and proliferation of smooth muscle cells (SMC) and endothelial cells (EC) exposed to various Mg‐alloys were analyzed. AMS and 316L were implanted into coronary arteries of Göttingen minipigs (n = 17) and explanted after 28 and 56 days. Stented arterial segments were analyzed prior to explantation by angiography and ex vivo by micro‐computer tomography (micro‐CT), by histology, and by immunohistochemistry. Exposure to the alloy in vitro resulted in reduced viability and proliferation of smooth muscle cells. Consistently, larger luminal diameter and less neointimal formation were found in AMS both 28 and 56 days after implantation. Histological analysis revealed no significant differences in the number of macrophages and Ki‐67 positive cells, yet a significantly higher number of proliferating cells around 316L struts at the earlier time point. The reduction in neointima formation and a larger vessel lumen indicates the superiority of the recently developed AMS over commercial available steel stents. Furthermore, AMS is absorbable, and thus will not cause stress to the stented vessel for the lifetime of the recipient.

Life-threatening common carotid artery blowout: rescue treatment with a newly designed self-expanding covered nitinol stent

Carotid blowout is a devastating complication in patients with head and neck malignancy. A covered stent offers an alternative to treatment of a carotid blowout patient thought to be at high risk for surgery or carotid occlusion. Stent placement in the common carotid artery or carotid bulb is a technical challenge because of large luminal diameter and luminal calibre discrepancy between internal carotid artery and common carotid artery. We present four patients with common carotid rupture and massive bleeding who were treated with self-expanding covered stents, among them, two cases were treated with newly designed self-expanding polytetrafluoroethylene (PTFE)-covered nitinol stents.

Miscellaneous 03

Background: Studies in hyperhidrosis have demonstrated that eccrine glands express all the signs of chronically activated normal glands but that the glands are otherwise morphologically normal. This study is the first to compare the morphology of normal and hyperhidrotic apocrine sweat glands. Methods: Apocrine sweat glands were isolated from the axilla of normal patients and hyperhidrotic individuals undergoing thoracic sypathectomy. Glands were wax embedded, sectioned (5 µm) and digital images analysed using analysis digital imaging software. All data are represented as mean ± s.e. from ≥30 observations. All tests of significance are Students t-test. Results: Hyperhidrotic glands were 30 per cent larger than normal in both length and width (length – normal 906 ± 71 µm versus 1173 ± 88 µm, P < 0.03: width – normal 613 ± 55 µm versus 811 ± 49 µm, P < 0.02). The tubule of the hyperhidrotic glands was significantly thicker (106.2 ± 2.6 µm versus 93.5 ± 4.9 µm; P < 0.03), whereas the hyperhidrotic lumen was 40 per cent wider than normal (56.6 ± 2.7 µm versus 40.6 ± 4.4 µm, P < 0.002). Excessive collagen matrix was excluded by measuring tubule area which was 60 per cent larger for hyperhidrotic glands compared to normal (257 575 ± 18 338 µm2versus 162 304 ± 12 971 µm2, P < 0.01) indicating that the hyperhidrotic glands were more tightly wound than normal. Conclusions: Apocrine sweat glands are not anatomically different in hyperhidrosis but are significantly larger, more coiled and have a larger luminal diameter. The cells also appear degranulated and more squamous suggesting increased activity. Hyperhidrosis is associated not only with increased eccrine activity but also affects apocine function.

High versus low-pressure balloon inflation during Multilink? stent implantation: Acute and long-term angiographic results

We compared the impact of low and high-pressure balloon inflation on acute and late angiographic results of Multilink stent. Low-pressure balloon inflation (9.5 +/- 1.9 atm) was used in 43 stents and high pressure (17.1 +/- 1.5 atm) in 44. A larger immediate luminal gain was achieved in stents with high-pressure balloon inflation (1.80 +/- 0.26 vs. 1.47 +/- 0.62; P = 0.002), resulting in a larger mean diameter in this group (2.71 +/- 0.37 vs. 2.48 +/- 0.47; P = 0.017). At follow-up, a larger luminal diameter was achieved in the high pressure group (1.93 +/- 0.72 vs. 1.45 +/- 0.66; P = 0.002) and a trend to a lower rate of angiographic restenosis (15% vs. 38%, P = 0.08).

Comparison of Conventional and Wire Mesh Expandable Prostheses and Surgical Bypass in Patients With Malignant Esophagorespiratory Fistulas

Background. Patients who present with malignant esophagorespiratory fistula continue to provide a significant palliative challenge to gastroenterologists and surgeons. Methods. This retrospective series reviewed 29 patients treated with conventional prostheses (13 patients), expandable wire mesh-coated prostheses (12 patients), and surgical bypass with esophageal exclusion (4 patients) between 1982 and 1995. Results. Improvement in dysphagia scores were comparable in all three groups. Fistula occlusion was more successful with expandable prostheses (92%) compared conventional prostheses (77%); however, reinterventions were required more commonly with expandable prostheses, which were also significantly more expensive on a unit cost basis. In selected patients in whom prosthesis placement either was inappropriate or failed, surgical bypass and esophageal exclusion was undertaken. These patients demonstrated good palliation with minimal morbidity and no mortality. Conclusions. Both conventional and expandable prostheses are safe and reasonably straightforward treatment modalities for patients with esophagorespiratory fistulas. Because of ease of insertion and large luminal diameter, expandable metal prostheses will see increasing use in treatment of these difficult patients; however, conventional prostheses will remain a good alternative, especially in patients with extrinsic esophageal compression. When stent placement is either unsuccessful or inadvisable, physiologically fit patients can undergo surgical bypass and esophageal exclusion with good palliation and minimal morbidity and mortality.

Six‐month Follow‐up of Successful Stenting for Acute Dissection After Coronary Angioplasty: Comparison Between Slotted Tube (Palmaz‐Schatz) and Flexible Coil (Gianturco‐Roubin) Stent Designs

The aim of this study was to evaluate the influence that two different stent designs may have in late outcome following successful coronary stent implantation for acute dissection after balloon angioplasty. In the present study, 50 consecutive patients were matched to compare late outcome between the use of slotted tube (Palmaz‐Schatz) and flexible coil (Gianturco‐Roubin) stent designs (25 in each group). Group matching was performed according to vessel size, location of target lesion, and dissection type among patients undergoing successful coronary stenting to treat an acute dissection following balloon coronary angioplasty. Poststent minimal luminal diameter (2.46 ± 0.49 mm vs 2.35 ± 0.47 mm, not significant [NS]) and acute luminal gain (2.02 ± 0.61 mm vs 1.85 ± 0.56 mm, NS) were similar in slotted tube and flexible coil stent groups, respectively. However, at 6‐month follow‐up, late loss in luminal diameter was larger in lesions treated with a flexible coil stent (0.96 ± 0.75 mm vs 0.62 ± 0.55 mm, P = 0.05), and minimal luminal diameter was smaller in those lesions treated with a flexible coil stent (1.38 ± 0.87 mm vs 1.84 ± 0.63 mm, P &lt; 0.05). Angiographic restenosis (&gt; 50% diameter narrowing) occured in four lesions treated with a slotted tube stent (16%) compared to ten lesions treated with a flexible coil stent (40%, P &lt; 0.05). The design of the coronary stent may have significant influence in the late lesion outcome. In patients with acute dissection following balloon coronary angioplasty, use of a slotted tube stent design (Palmaz‐Schatz) may result in lower late loss and larger luminal diameter at 6‐month follow‐up than use of a flexible coil stent design (Gianturco‐Roubin).

Early and Late Clinical Outcomes after Directional Coronary Atherectomy

Background：Restenosis is a major limitation of balloon angioplasty. Recently, new angiop-lasty devices have been used in an attempt to reduce the restenosis compared with coronary balloon angioplasty. Directional coronary atherectomy effectively dilated the lesion by removal of the atherosclerotic plaque. Therefore, we tried to evaluate immediate and late clinical outcomes after directional coronary atherectomy in the 57 patients with coronary artery disease. Methods：From October 1991 to March 1997, fifty seven consecutive patients with 69 lesions were treated with directional coronary atherectomy. The patients underwent coronary angiography at pre-intervention, immediately after intervention and at 6 months post-interven-tion. Restenosis was assessed clinically and by computer-assissted quantitative measurements of luminal dimensions. Patients were requested to undergo coronary angiography at 6 months after directional coronary atherectomy. Angiographic restenosis was defined as more than 50% diameter stenosis by quantitative coronary angiographic analysis. Results：Successful results were achieved in 61 of the 69 lesions(88% and mean stenosis was reduced from 78.0±13.0% to 10.0±5.0%. Atherectomy resulted in an increase in minimal lumen diameter from 0.8±0.3mm to 3.0±0.6mm. Six months follow-up angiogram was obtained in 68% of 50 eligible lesions. The overall angiographic restenosis rate was 32%. Six-month clinical follow-up was obtained in 94% of the eligible lesions. The clinical recurrence occured in 38% of the patients. The target lesion revascularization rate was 17%. Conclusions：Removal of coronary artery plaque with directional atherectomy led to large luminal diameter and six months follow-up angiography shows an overall restenosis rate of 32%. However, further clinical study is warranted to evaluate the efficacy of atherectomy with larger numbers of patients.