Site Of Stenosis Research Articles

Impaired Apoptosis of Pulmonary Endothelial Cells Is Associated With Intimal Proliferation and Irreversibility of Pulmonary Hypertension in Congenital Heart Disease

This study sought to assess the cellular and histologic basis of irreversible pulmonary hypertension (PHT) in the clinical setting of congenital heart disease (CHD). Although many children with CHD develop pulmonary vascular disease, it is unclear why this complication is reversible after complete repair in some cases but irreversible in others. Because failure of endothelial cell apoptosis might lead to intimal proliferation and lack of reversibility of PHT, we investigated this and other key markers of vasoactivity and angiogenesis in subjects with PHT and CHD. We assessed antiapoptotic and proapoptotic markers in vascular and perivascular cells in lung biopsy samples from 18 patients with CHD, 7 with reversible and 11 with irreversible PHT, and 6 control patients. Immunostaining for endothelial nitric oxide synthase, vascular endothelial growth factor, and CD34 (markers of vasoactivity and neoangiogenesis) was also performed. The antiapoptotic protein Bcl-2 was highly expressed by pulmonary endothelial cells in all cases of irreversible PHT but in no cases of reversible PHT, nor in control patients (p < 0.001). Intimal proliferation was present in 10 of 11 irreversible PHT cases, but never observed in reversible PHT (p < 0.001). Similarly, perivascular inflammatory T-cells expressed more antiapoptotic proteins in irreversible PHT (p < 0.01). Irreversible PHT cases were also more likely to show compensatory upregulation of vascular endothelial growth factor and new small vessel formation at the sites of native vessel stenosis or occlusion (p < 0.001). Irreversible PHT is strongly associated with impaired endothelial cell apoptosis and antiapoptotic signaling from perivascular inflammatory cells. These changes are associated with intimal proliferation and vessel narrowing, and thereby may contribute to clinical outcomes associated with pulmonary hypertension.

Postlaminectomy Spinal Stenosis after Lumbar Discectomy

Study Design: Retrospective study Objectives: To investigate the type of postsurgical spinal stenosis in patients who had undergone a primary laminectomy and discectomy for a herniated lumbar disc, and to evaluate the clinical outcomes of the revision operation. Summary and Literature Review: Spinal stenosis occurs frequently after a laminectomy and discectomy. Facet joint arthritis, hypertrophy of the ligamentum flavum, iatrogenic instability, postsurgical scarring or any combination of these conditions can cause spinal stenosis. Materials and Methods: Twenty-four patients, who had postsurgical spinal stenosis were reviewed. Patients with a simple recurrent disc herniation without a spinal stenosis were excluded. The mean age was 52.5 years (range 31~70). There were 19 males and 5 females. The primary discectomy were performed at L4-5 in 21 patients, L5-1 in 2 patients, and both L4-5 and L5-1 in 1 patient. The mean interval between the first discectomy and revision surgery was 11.6 years (range 2.7~40). The anatomical site of the spinal stenosis, combined herniated disc, height of the disc space, segmental instability, hypertrophy of facet joint and thickening of the ligamentum flavum in radiographs was evaluated. The clinical outcome was measured using the Oswestry disability index. Results: Lateral spinal stenosis was observed in all patients. Eight patients showed both central and lateral stenosis. The lateral stenosis was caused by hypertrophy of the facet joint in 20 patients and a thickening of the ligamentum flavum in 8 patients. Nineteen patients showed herniated lumbar disc, including disc protrusion in 8 patients, disc extrusion in 9 patients, and disc sequestration in 2 patients. A loss of disc height was observed in 12 patients, segmental instability in 5 patients, and spondylolisthesis in 3 patients. All the patients received posterior decompression and posterolateral fusion with pedice screw instrumentation. Eighteen patients received a discectomy simultaneously. The average Oswestry score at the last visit was 24.4. Conclusions: Postlaminectomy spinal stenosis resulted from a lateral spinal stenosis associated with facet joint hypertrophy. Recurrent disc herniation also contributed to the novel development of symptoms. A wide decompression and fusion provided good clinical outcomes.

Percutaneous treatment of the superior vena cava syndrome via an excimer laser sheath in a patient with a single chamber atrial pacemaker

A 21-year-old woman presented with a pacemaker-associated superior vena cava (SVC) syndrome refractory to medical therapy. In the past, treatment of this condition has involved surgical exploration which is invasive. With the evolution of percutaneous techniques, treatment has included venoplasty and stenting over the pacemaker lead. There is limited experience with a more advanced percutaneous technique in which the lead is extracted by an excimer laser sheath. The extraction is immediately followed by venoplasty and stenting at the site of stenosis with subsequent implantation of a new permanent pacemaker at the previously occluded access site. The patient underwent this procedure which proved to be safe, minimally invasive, and an efficient method of treating SVC syndrome secondary to a single chamber atrial pacemaker.

Outcome of Endoscopic Management of Extensive Laryngotracheal Stenosis

When performing endotracheal intubation or tracheotomy in unconscious patients in emergent situations, one should consider the possibility of the later complication of laryngotracheal stenosis, which can result in difficulties with decannulation. We analyzed the clinical features of laryngotracheal stenosis to search for its possible etiologic factors and its proper preventive methods. The medical records of 249 cases of laryngotracheal stenosis out of 2,208 patients who underwent tracheotomy in our hospital during the past 12 years were retrospectively reviewed regarding several parameters, such as the duration of endotracheal intubation, site of tracheostoma, site of stenosis, treatment method, and so forth. Non-otolaryngologists had a tendency to place the tracheostoma at a higher level of the trachea. We identified technical precautions that should be taken into consideration in performing an emergency tracheotomy. Bronchoscopic evaluation and tracheal stent insertion was the most commonly used treatment method. Successful decannulation was achieved in about 70%, and was especially frequent in patients whose endotracheal intubation was less than 20 days. It is desirable that the duration of endotracheal intubation be limited to less than 20 days. A database of patients who undergo tracheotomy should be submitted to careful follow-up to diagnose early development of laryngotracheal stenosis and to prevent long-term complications.

Left Ventricular Outflow Obstruction

Left ventricular outflow tract obstructions (LVOTOs) encompass a series of stenotic lesions starting in the anatomic left ventricular outflow tract (LVOT) and stretching to the descending portion of the aortic arch (Figure 1). Obstruction may be subvalvar, valvar, or supravalvar. These obstructions to forward flow may present alone or in concert, as in the frequent association of a bicuspid aortic valve with coarctation of the aorta. All of these lesions impose increased afterload on the left ventricle and, if severe and untreated, result in hypertrophy and eventual dilatation and failure of the left ventricle. LVOTOs are congenital in the vast majority of individuals younger than 50 years in the United States; some variants of subaortic obstruction are the exception. It is imperative to consider all patients with LVOTO at a high risk for developing infective endocarditis, and one should always institute appropriate measures for prophylaxis. The present article is intended as a contemporary review of the causes, manifestations, treatments, and outcomes of LVOTO; it will not address LVOTO in the pediatric population or genetic hypertrophic cardiomyopathy but will focus strictly on congenital malformations in the adult. Figure 1. Artist’s rendering of the LVOTO lesions in sequence as viewed from a superolateral orientation. A, Gradient echo cardiac MR image as viewed from the frontal projection demonstrating flow acceleration at a site of supravalvar aortic stenosis (white arrow) in a patient with Williams syndrome. The black arrow identifies the level of the unrestricted aortic valve. B, Classic radiological signs of coarctation of the aorta: rib notching (white arrows) as seen on a posteroanterior chest x-ray in a patient with coarctation of the aorta. The rib notching is caused by erosion of the inferior rib margins by dilated pulsatile posterior intercostals collateral arteries. The black arrow points to the Figure 3 silhouette that …

Percutaneous Continuous Aortic Flow Augmentation for Cardiac Recovery in a Chronic Heart Failure Patient With Peripheral Vascular Disease

Peripheral vascular disease is an obstacle to the use of continuous aortic flow augmentation (CAFA). The authors used CAFA in a patient with a 50% stenosis of the left iliac artery. Five hours after initiating therapy, flow rates dropped from 1.47 L/min to 0.2 L/min, possibly due to obstruction around the inflow cannula near the site of the iliac artery stenosis. Flow was stabilized by adequate fluid infusion and successfully restored by slightly withdrawing the tip of the inflow catheter. This finding suggests that peripheral vascular disease is a relative-not an absolute-contraindication for CAFA, but requires close monitoring of flow during CAFA therapy.

A numerical study of non-Newtonian blood flow in stenosed coronary artery bypass with grafts

We investigate the behaviour of the pulsatile blood flow in a stenosed right coronary artery with a bypass graft. The human blood is assumed as a non-Newtonian fluid and its viscous behaviour is described by the Carreau model. The transient phenomena of blood flow through the stenosed region and the bypass graft are simulated for five cardiac cycles by solving the three dimensional unsteady Navier--Stokes equations coupled with the non-Newtonian model. Effects of the time variations of pulsatile velocity and pulse pressure are taken into account. The influence of the bypass angle on the flow interaction between the jet flow from the native artery and the flow from the bypass graft is investigated. Distributions of velocity, pressure and wall shear stresses are determined under various conditions. The results show that the blood pressure in the stenosed artery drops dramatically in the stenosis area and that high wall shear stresses occur around the stenosis site.

How much can we learn from long-term extension trials in multiple sclerosis?

<h3>Summary</h3> <h3>Background and objectives</h3> Given different sites of stenosis and access blood flow rates (Qa), the criteria for diagnosing fistula stenosis might vary according to anastomotic site. To test this, we analyzed the database of a prospective blinded study seeking an optimal bedside screening program for fistula stenosis. <h3>Design, setting, participants, &amp; measurements</h3> Several methods used during dialysis (physical examination [PE], dynamic and derived static venous pressure [VAPR], dialysis blood pump flow/arterial pressure ratio, and Qa measurement) to diagnose angiographically-proven &gt;50% stenosis were assessed in an unselected population of hemodialysis patients with mature fistulae (43 at the wrist [distal fistulae], 76 at mid-forearm or the elbow [proximal fistulae]). <h3>Results</h3> Prevalence of inflow stenosis was uninfluenced by anastomotic site, whereas outflow stenoses were more prevalent in proximal fistulae. The best test for inflow stenosis was Qa &lt;650 ml/min in distal fistulae and a combination of a positive PE and Qa &lt;900 ml/m in proximal fistulae. In proximal fistulae, PE and VAPR &gt;0.5 were both equally highly diagnostic of outflow stenosis. Tailoring choice of test to site of the anastomosis may also contain the screening-associated workload, by reducing the need to perform PE and measure VAPR, compared with a screening approach regardless of the access location. <h3>Conclusions</h3> Our study shows that an effective bedside screening program with ≥85% accuracy for fistula stenosis can be tailored to the site of the anastomosis, Qa being the tool of choice for the wrist, and PE alone or combined with Qa and VAPR measurements for more proximally-located accesses.

Progressive epicardial coronary blood flow reduction fails to produce ST-segment depression at normal heart rates

ST-segment depression is commonly seen in patients with acute coronary syndromes. Most authors have attributed it to transient reductions in coronary blood flow due to nonocclusive thrombus formation on a disrupted atherosclerotic plaque and dynamic focal vasospasm at the site of coronary artery stenosis. However, ST-segment depression was never reproduced in classic animal models of coronary stenosis without the presence of tachycardia. We hypothesized that ST-segment depression occurring during acute coronary syndromes is not entirely explained by changes in epicardial coronary artery resistance and thus evaluated the effect of a slow, progressive epicardial coronary artery occlusion on the ECG and regional myocardial blood flow in anesthetized pigs. Slow, progressive occlusion over 72 min (SD 27) of the left anterior descending coronary artery in 20 anesthetized pigs led to a 90% decrease in coronary blood flow and the development of ST-segment elevation associated with homogeneous and transmural myocardial blood flow reductions, confirmed by microspheres and myocardial contrast echocardiography. ST-segment depression was not observed in any ECG lead before the development of ST-segment elevation. At normal heart rates, progressive epicardial stenosis of a coronary artery results in myocardial ischemia associated with homogeneous, transmural reduction in regional myocardial blood flow and ST-segment elevation, without preceding ST-segment depression. Thus, in coronary syndromes with ST-segment depression and predominant subendocardial ischemia, factors other than mere increases in epicardial coronary resistance must be invoked to explain the heterogeneous parietal distribution of flow and associated ECG changes.

Inflow Stenoses in Dysfunctional Hemodialysis Access Fistulae and Grafts

The aim of the study is to prospectively determine the incidence of inflow stenoses in dysfunctional hemodialysis access arteriovenous fistulae (AVFs) and grafts (AVGs). Contrast-enhanced magnetic resonance angiography (CE-MRA) was performed of 66 dysfunctional AVFs and 35 AVGs in 56 men and 45 women (mean age, 62 years; age range, 31 to 86 years). Complete inflow (from the subclavian artery), shunt region, and complete outflow (including subclavian vein) were shown at CE-MRA. In addition to standard digital subtraction angiography (DSA) of the shunt region and outflow, DSA of the complete inflow was obtained through access catheterization of all cases in which CE-MRA showed an inflow stenosis. Vascular stenosis is defined as greater than 50% decrease in luminal diameter compared with an uninvolved vascular segment located adjacent to the stenosis. Endovascular intervention of stenoses was performed in connection with DSA. CE-MRA showed 19 arterial stenoses in 14 patients (14%). DSA confirmed 18 of these lesions in 13 patients and showed no additional inflow lesions. Of the 13 patients, 7 patients had arterial stenoses only and 6 patients had accompanying stenoses in the shunt region and/or outflow. Referral criteria for the 13 patients to undergo access evaluation had been decreased flow rates (9 patients), steal symptoms (2 patients), and insufficient access maturation (2 patients). Access flow of the 9 patients with a low-flow access improved from 477 +/- 74 mL/min to 825 +/- 199 mL/min after angioplasty. One patient with steal symptoms became symptom free after angioplasty. Endovascular intervention in 3 patients proved to be unsuccessful. Inflow stenoses are not uncommon in dysfunctional hemodialysis access shunts. We suggest that radiological evaluation comprise assessment of the complete arterial inflow.

Simulation of Pulsatile Flow of Blood in Stenosed Coronary Artery Bypass with Graft

In this paper, we investigate the behavior of the pulsatile blood flow in a stenosed right coronary artery with a bypass graft. The human blood is assumed to be a non-Newtonian fluid and its viscous behavior is described by the Carreau model. The transient phenomena of blood flow though the stenosed region and the bypass grafts are simulated by solving the three dimensional unsteady Navier-Stokes equations and continuity equation. The influence of the bypass angle on the flow interaction between the jet flow from the native artery and the flow from the bypass graft is investigated. Distributions of velocity, pressure and wall shear stresses are determined under various conditions. The results show that blood pressure in the stenosed artery drops dramatically in the stenosis area and that high wall shear stresses occur around the stenosis site.

Anticorps recombinants antithrombotiques

Coronary syndromes, stroke and other ischaemic arterial diseases are the leading cause of death in the world and will probably remain it at least until 2020. Cardiovascular diseases kill 17 million people each year with an expected increase to 20 million in 2020 and 24 million in 2030. The global impact of recurrence and death during the 6 months following an acute coronary syndrome remains at 8-15% in the present state of medical practice. Acute ischaemic syndromes have a common aetiology that is the formation of a platelet-rich clot at the site of severe coronary stenosis and of eroded atherosclerotic plaques. Therapy consists of medical treatments associating thrombolysis, antiplatelet drugs, and the re-opening of the coronary artery by angioplasty. But these treatments do not prevent morbidity and mortality reaching 15% at 6 months. Finally the treatment of stroke is very limited. There is thus a real clinical need to improve existing treatments and to discover new molecules. Platelet activation is a critical step in ischaemic cardiovascular diseases. This is the reason why antiplatelet drugs are most often prescribed in these cases. Currently, only one recombinant antithrombotic antibody is used in therapy. This is a chimeric Fab, c7E3 or abciximab, which inhibits the final phase of platelet aggregation. Abciximab is prescribed in acute coronary syndromes treated by angioplasty. However, treatment by abciximab can induce severe complications, principally, hemorrages and thrombopenia. Other platelet receptors involved in the earlier steps of platelet activation, such as the phases of contact with and of activation by the subendothelium matrix, have been identified as potential targets for the development of antithrombotic antibodies and are described in this revue.

Percutaneous Treatment of a Large Vein Graft Aneurysm With Covered and Conventional Stents

A 75-year-old man presented with typical angina 13 years after coronary artery bypass grafting. Angiography demonstrated a patent internal mammary graft to the left anterior descending artery and vein graft to the obtuse marginal branch of the left circumflex artery. The large-caliber right coronary graft had a large false aneurysm in its midportion, at the site of a severe stenosis. The aneurysm …

Comparison of X‐ray fluoroscopy and interventional magnetic resonance imaging for the assessment of coronary artery stenoses in swine

The accuracy of a two-step interventional MRI protocol to quantify coronary artery disease was compared to the clinical gold standard, X-ray angiography. Studies were conducted in nine swine with a surgically induced stenosis in the proximal left circumflex coronary artery. The two-step protocol consisted of catheter-directed magnetic resonance angiography (MRA), which was first used to localize the stenosis, followed by MRI cross-sectional images to quantify the degree of stenosis without the use of contrast agent. Line signal intensity profiles were drawn across the vessel diameter at the stenosis site and proximal to the stenosis for each data set to measure percentage stenosis for each animal. Catheter-directed MRA successfully detected eight of nine stenoses. Cross-sectional MRI accurately quantified each stenosis, with strong agreement to the measurements made using X-ray fluoroscopy (intraclass correlation coefficient = 0.955; P < 0.05). This study demonstrates that in the future interventional MRI may be an alternative to X-ray angiography for the detection and quantification of coronary artery disease.

Effects of sumatriptan and eletriptan on diseased epicardial coronary arteries

Triptans are contraindicated in patients with known or suspected coronary artery disease (CAD); however, few studies have evaluated triptans in patients with obstructive CAD to quantify the vasoconstrictive effect on diseased coronary vessels. Patients undergoing percutaneous transluminal coronary angioplasty for symptomatic single-vessel CAD were randomised to one of three parallel cohorts to receive (1) 6 mg intravenously (IV) infused eletriptan plus subcutaneous (SC) placebo, (2) IV infused placebo plus 6 mg SC sumatriptan or (3) IV infused placebo plus SC placebo, as simultaneous administrations in a double-blind manner. Serial arteriograms, hemodynamic indices, electrocardiography and triptan plasma concentrations were obtained. . Fifteen minutes after triptan challenge, median (95% confidence interval) changes in coronary artery diameter (CADM) at the focal point of the stenosed segment were: dilation of 2.6% (-5.0, 11.4), eletriptan 6 mg IV (n = 18); constriction of 6.8% (-12.6, 0.4), sumatriptan 6 mg SC (n = 17), and constriction of 4.5% (-7.0, 7.9), placebo (n = 10). One patient had angiographic evidence of a new thrombus at the stenosis site, necessitating termination of study infusion and successful stenting of the lesion. There was no correlation between effects on CADM and triptan concentration, or between hemodynamic or electrocardiograph changes and the presence (n = 13) or absence (n = 33) of chest pain. Triptans had very little effect on diseased epicardial coronary arteries in a small group of angina sufferers with established CAD. Results should be interpreted cautiously since there may be instances where even modest triptan-associated epicardial constriction is sufficient to precipitate myocardial ischemia in patients with severe obstructive CAD.

Adaptation of the Folts and electrolytic methods of arterial thrombosis for the study of anti-thrombotic molecules in small animals

Introduction Animal preparations of arterial thrombosis play a crucial role in the discovery and validation of novel drug targets in vivo, aiding in the selection of new drugs for clinical evaluation. The Folts and electrolytic methods of arterial thrombosis are two of the most commonly used techniques to investigate drugs with novel anti-thrombotic potential. However, these techniques often involved the use of large animals such as dogs, and their application to small animals was limited. The aim of the present study was to adapt the Folts and electrolytic methods previously described in large animals to create highly reproducible, quantitative models of arterial thrombosis in mice, rats and rabbits. Methods Carotid artery blood flow was measured in anaesthetised mice, rats and rabbits. In the Folts-like method, a silk suture was tied around one carotid artery distal to a flow probe and tightened to cause a concentric stenosis sufficient to decrease blood flow by 50%. Intimal damage was induced by pinching the artery at the site of stenosis using forceps. The sequential formation and mechanical dislodgement of the resultant platelet-rich occlusive thrombus caused cyclic carotid artery flow reductions. In the electrolytic method in mice, a platinum hook electrode was placed distal to a flow probe on one carotid artery. The artery was clamped distally to the electrode to cause stasis and an electrical current (4 mA for 1.25 min) was applied before clamp release. This induced vascular injury resulting in occlusive thrombus (platelet- and fibrin-rich) formation. Conclusion The Folts-like method of arterial thrombosis was successfully adapted for use in mice, rats and rabbits, and the electrolytic technique for use in mice. Compared with larger animals, these methods are highly reproducible and ideal for pre-clinical, cost-effective, low-cost routine screening of novel anti-thrombotic drugs.

Combined pulmonary stenosis and insufficiency preserves myocardial contractility in the developing heart of growing swine at midterm follow-up

This study was conducted to determine the effects of chronic combined pulmonary stenosis and pulmonary insufficiency (PSPI) on right (RV) and left ventricular (LV) function in young, growing swine. Six pigs with combined PSPI were studied, and data were compared with previously published data of animals with isolated pulmonary insufficiency and controls. Indexes of systolic function (stroke volume, ejection fraction, and cardiac functional reserve), myocardial contractility (slope of the end-systolic pressure-volume and change in pressure over time-end-diastolic volume relationship), and diastolic compliance were assessed within 2 days of intervention and 3 mo later. Magnetic resonance imaging was used to quantify pulmonary insufficiency and ventricular volumes. The conductance catheter was used to obtain indexes of the cardiac functional reserve, diastolic compliance, and myocardial contractility from pressure-volume relations acquired at rest and under dobutamine infusion. In the PSPI group, the pulmonary regurgitant fraction was 34.3 +/- 5.8%, the pressure gradient across the site of pulmonary stenosis was 20.9 +/- 20 mmHg, and the average RV peak systolic pressure was 70% systemic at 12 wk follow-up. Biventricular resting cardiac outputs and cardiac functional reserves were significantly limited (P < 0.05), LV diastolic compliance significantly decreased (P < 0.05), but RV myocardial contractility significantly enhanced (P < 0.05) compared with control animals at 3-mo follow-up. In the young, developing heart, chronic combined PSPI impairs biventricular systolic pump function and diastolic compliance but preserves RV myocardial contractility.

Notions d’hémodynamique et techniques ultrasonores pour l’exploration des artères

Arterosclerosis is the main cause of arterial lesions and leads to arterial stenoses. In order to preserve distal perfusion, flow velocities increase at the site of stenosis due to reduced peripheral resistance. Doppler sonography (US) allows detection of hemodynamic abnormalities at the site of stenosis and evaluation of its impact on distal flow. Several parameters and imaging features including resistive indices and systolic velocities are measured in order to characterize the degree of stenosis and its impact on perfusion. In addition, B-mode US allows morphologic evaluation of lesions. Doppler US is useful to evaluate lower limb arteries, renal arteries and neck arteries.

Increased internal carotid artery peak systolic velocity is associated with presence of significant atherosclerotic plaque instability independent of degree of ICA stenosis

The aim of our work was to study the relationship between Doppler ultrasound velocity measurements and the presence of histologic features of plaque instability in carotid atherosclerosis, in particular, intraplaque hemorrhage (IPH). Consecutive patients undergoing carotid endarterectomy in a one-year period were included. All patients were examined by duplex ultrasonography and carotid angiography. Endarterectomy specimens were examined histologically for features of plaque instability. The quantity of IPH was measured by digital image analysis. The associations between Peak Systolic Velocity (PSV), end-diastolic velocity (EDV), degree of ICA stenosis, shape and length of the lesion and the features of plaque instability and quantity of IPH were assessed. Seventy-four patients (20 asymptomatic, 54 symptomatic) were included. PSV was independently associated with the presence of significant IPH [p < 0.001, OR = 1.04 (95% CI = 1.01–1.06)], as was the degree of angiographic ICA stenosis [p < 0.05, OR = 0.98 (95% CI = 0.92–1.6)]. Neither EDV nor the shape of the lesion was associated with IPH (p = 0.26 and p = 0.38, respectively). A close correlation was observed between PSV and the quantity of IPH (r 2 = 0.68, p < 0.0001). A significant association was observed between PSV and the presence of plaque ulceration (p < 0.05); however, this was not found to be independent of the quantity of IPH and the degree of ICA stenosis [p = 0.17, OR = 1.28 (95% CI = 0.6–2.44)]. PSV at the site of ICA stenosis appears to be associated with the quantity of intraplaque hemorrhage, independent of the angiographic degree of ICA stenosis. We propose that the role of Doppler velocity measurements extends beyond measurement of the degree of ICA stenosis. Increased ICA peak systolic velocity by itself may be an indicator of atherosclerotic plaque instability.

Topical Mitomycin C in the Prevention of Keloid Scar Recurrence

To assess the ability of mitomycin C to prevent the recurrence of surgically excised keloid scars. Mitomycin C has been successfully used to prevent scar tissue formation at the site of subglottic stenosis in the field of pediatric otolaryngology. It appears that mitomycin C interferes with the ability of fibroblasts to produce a scar without causing changes in epithelialization. We excised keloid scars from various sites in the head and neck and then applied mitomycin C to the resected bed prior to closure of the wound at a concentration of 0.4 mg/mL for 5 minutes. All patients had multiple keloids and acted as their own control. At 1 month after the procedure both wounds were started on a regimen of triamcinolone acetonide, 40 mg/mL injections, repeated every month for 6 months. At the end of the study, photos and measurements were again taken. Fifteen patients (13 female and 2 male) ranging in age from 10 to 55 years enrolled in the study. No infections or nonhealing wounds were seen. There was no difference in postoperative pain. Eight patients completed the triamcinolone injections, 5 had fewer than 6 injections, and 2 patients had no steroid injections. Twelve patients completed follow-up and were evaluated for surgical complications and recurrence of the keloids at either site. Two patients had partial postoperative follow-up in person and then completed follow-up via telephone. One patient could not be found for follow-up. Four patients had recurrence of both excised lesions. Ten patients had no recurrence of their keloids at either site. Mitomycin C made no difference in the prevention of keloid recurrence after excision when topically applied.