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Carotid plaque vulnerability features beyond the degree of stenosis may play a key role in the pathogenesis and recurrence of ischemic cerebrovascular events. This study sought to compare intraplaque hemorrhage (IPH) as a marker of plaque vulnerability in symptomatic patients with mild ( We included patients who experienced ischemic cerebrovascular events with no other identifiable sources and underwent carotid endarterectomy for mild (n=32), moderate (n=47), and severe (n=58) carotid artery stenosis. The degree of stenosis and imaging hallmarks were assessed by computed tomography angiography or magnetic resonance angiography. Plaque specimens were stained with hematoxylin and eosin and Movat pentachrome staining. Carotid plaques of patients with mild stenosis had a higher extent of IPH (%) on tissue analysis compared with patients with moderate (mild, 15.7% [interquartile range, 7.8%–26.7%]; moderate, 3.9% [0.0%–9.2%]; P P P Our major finding is the association of IPH with mild carotid artery stenosis based on histological analysis. The current study may suggest that IPH potentially plays a role in the mechanism of stroke in patients with nonobstructive carotid stenosis.

In order to understand the irregular flow conditions of blood in a locally constricted blood vessel, analytical results are obtained for a porous effect on oscillatory blood flow that acts as a Newtonian flow. Compared to the radius of the unconstricted tube, the surface roughness is presumed to be cosine-shaped and the maximum height of the roughness is very small. The main focus of investigation of the porous effect on oscillatory arterial blood flow with mild stenosis, a mathematical model has been developed.

Arterial stenosis is an abnormal condition in arteries due to the deposition of fats and other substances, called atherosclerosis. As it restricts the blood flow, it may induce a heart attack. Employing the Navier-Stokes equations, we consider the blood flow in an artery with the presence of a stenosis in an axisymmetric shape. We analyze the blood flow dynamics in cylindrical form by evaluating pressure, pressure drop against the wall, shear stress on the wall. We also analyze the dynamics by evaluating the ratio of pressure drop with stenosis to the pressure drop without stenosis against the wall, and the ratio of maximum to minimum shear stresses with the ratios of various thicknesses of stenosis to radius of the artery.

A 52-year-old man, with a history of allergic rhinitis and without coronary risk factors, transferred to our hospital because of cardiac arrest. Coronary angiography revealed no significant stenosis in left coronary arteries ([Figure 1A][1]), and mild stenosis in right coronary artery ([Figure 1B

As the degree of luminal narrowing increases, shear stress increases, and high shear stress is known to activate platelets. However, the relationship between the degree of luminal narrowing and the composition of thrombus in patients with plaque erosion has not been studied. A total of 148 patients with plaque erosion and thrombus detected by optical coherence tomography were divided into tertiles based on the minimum lumen area (MLA) at the culprit lesion. Thrombus was categorized as platelet-rich or fibrin-rich. Among 148 patients, 50 (34%) were in the mild stenosis group, 49 (33%) were in the moderate stenosis group, and 49 (33%) were in the severe stenosis group. The composition of thrombus was significantly different among the 3 groups (prevalence of platelet-rich thrombus was 60% in the mild stenosis group; 78% in the moderate stenosis group; and 84% in the severe stenosis group; P = 0.021). The pattern of fibrin-rich thrombus showed the opposite: 40%, 22%, and 16%, respectively. In the multivariate analysis, current smoking was independently associated with fibrin-rich thrombus (odds ratio [OR] 2.364 [95% CI 1.004–5.567], P = 0.049). This study demonstrated that platelet-rich thrombus was the predominant type of thrombus in plaque erosion. The prevalence of fibrin-rich thrombus was highest in the mild stenosis group.

Objective Measurement of the degree of stenosis is not enough to decide on the treatment strategy for patients with carotid stenosis. Plaque morphology examination is needed for such a decision-making. Thus, we evaluated the usefulness of plaque magnetic resonance imaging (MRI) to decide on the modality of treatment for patients with carotid atherosclerotic plaques. Materials and Methods Fifteen patients presenting with carotid stenosis between 2014 and 2016 were included. They underwent angiography for measurement of the degree of stenosis. Carotid plaques were visualized using MRI. Results There were six (40%) stable and nine (60%) unstable plaques. Seven symptomatic patients (77.7%) had unstable lesions and two symptomatic patients (33.3%) had stable lesions (p = 0.096). There were six (40%) intraplaque hemorrhage (IPH) cases. There were six symptomatic patients (100%) in the IPH group and three symptomatic patients (33.3%) in the non-IPH group (p = 0.013). The mean stenosis degree was 58.9% in the IPH group and 70.4% in the non-IPH group (p = 0.094). Symptoms occurred irrespective of the degree of the stenosis in the IPH groups. In the IPH group, the recurrent ischemic cerebrovascular event rate was 33.3%. Particularly, the recurrent ischemic cerebrovascular event rate was 66.7% in the IPH group with mild stenosis treated with medications. Conclusion IPH in plaque MRI is significantly associated with ischemic symptoms and has a high risk for subsequent ischemic cerebrovascular events irrespective of the degree of stenosis. Plaque MRI is a useful tool in predicting symptomatic risks for carotid stenosis irrespective of the degree of such stenosis.

Objectives This study sought to obtain in vivo data to confirm assumptions on device loading conditions and assess procedural feasibility, safety, and valve performance. Background The Harmony transcatheter pulmonary valve (Medtronic, Minneapolis, Minnesota) was designed for patients with severe pulmonary regurgitation who require pulmonary valve replacement. Methods Three sites participated in this first Food and Drug Administration–approved early feasibility study using an innovative device design to accommodate the complex anatomy of the right ventricular outflow tract. Potentially eligible patients underwent review by a screening committee to determine implant eligibility. Six-month outcomes are reported. Results Between May 2013 and May 2015, 66 subjects were enrolled, and 21 were approved for implant and underwent catheterization; 20 were implanted. Catheterized patients had a median age of 25 years, were predominantly diagnosed with tetralogy of Fallot (95%), had severe pulmonary regurgitation (95%), and had trivial or mild stenosis. The device was delivered in the desired location in 19 of 20 (95%) patients. Proximal migration occurred in 1 patient during delivery system removal. Two devices were surgically explanted. Premature ventricular contractions related to the procedure were reported in 3 patients; 2 were resolved without treatment. One patient had ventricular arrhythmias that required treatment and later were resolved. At 1 month, echocardiography revealed none or trivial pulmonary regurgitation in all and a mean right ventricular outflow tract gradient of 16 ± 8 mm Hg (range 6 to 31 mm Hg). Conclusions In this feasibility study of the Harmony transcatheter pulmonary valve device, there was high procedural success and safety, and favorable acute device performance.

We report the case of a young boy with a history of total occlusion of the superior caval vein, diagnosed early after complex neonatal cardiac surgery, who developed severe protein-losing enteropathy. Protein-losing enteropathy was precipitated by a relatively mild stenosis at the junction of the inferior caval vein with the right atrium. Percutaneous stent dilation of the veno-atrial junction definitively relieved the stenosis, and the protein-losing enteropathy subsequently resolved.

Mitral valve construction using decellularized bovine pericardium is a new procedure. A 10-month-old infant with neonatal Marfan syndrome underwent mitral valve replacement due to severe mitral regurgitation with a cylinder valve constructed from decellularized bovine pericardium. Nineteen months postoperatively the patient is clinically well with trivial mitral regurgitation, mild stenosis, and without need for anticoagulation.

Supplemental Digital Content is available in the text., Background— Patients with nonobstructive coronary artery disease (NOCAD; wall irregularities, stenosis

ObjectiveThe majority of acute coronary syndromes occur in the absence of obstructive coronary artery disease (CAD), and the underlying biobehavioral processes are not well understood. Depressive symptoms and anxiety are predictive of prognosis, and have been associated with markers of inflammation that play a role in atherosclerosis. This study examines whether depressive symptoms and anxiety are associated with higher levels of high-sensitive C-reactive protein (hs-CRP) and fibrinogen in patients with non-obstructive CAD.MethodsPatients with non-obstructive CAD (“wall irregularities”, stenosis < 60%, N = 414, mean age 62.1 ± 9.3 years, 52% women) in the TweeSteden Mild Stenosis (TWIST) observational cohort study completed the Hospital Anxiety and Depression Scale (HADS). Blood samples were analyzed for hs-CRP and fibrinogen. The cross-sectional association of anxiety and depressive symptoms with hs-CRP and fibrinogen, adjusting for covariates, was examined by multivariate regression analysis.ResultsDepressive symptoms were positively associated with hs-CRP level (β = .135, p = .009), but not fibrinogen (β = .075, p = .153), adjusted for age and sex. Additional adjustments for sociodemographic, disease severity and lifestyle factors rendered the association non-significant. In the fully adjusted model, depressive symptoms were not associated with hs-CRP (β = .036, p > 0.10) and BMI was the only variable that was independently associated with hs-CRP (β = .203, p < .001). No associations were observed for anxiety with either hs-CRP or fibrinogen (p > 0.10).ConclusionAmong patients with non-obstructive CAD, depressive symptoms and anxiety were not independently associated with hs-CRP and fibrinogen.Keywords: Non-obstructive coronary artery disease, Depression, Anxiety, hs-CRP, Fibrinogen, BMI, Lifestyle

Heat and mass transfer effects on Newtonian biomagnetic fluid of blood flow through a tapered porous artery with a stenosis is investigated. Governing equations have been modeled by treating blood as Newtonian biomagnetic fluid. The governing equations are simplified under the assumption of mild stenosis. Exact solutions have been evaluated for velocity, temperature, and concentration profiles. The effects of Newtonian nature of blood on velocity, temperature, concentration profile, wall shear stress, shearing stress at the stenosis throat and impedance of the artery are discussed graphically. Stream lines have been presented in last section of the article.

One hundred patients with infrarenal abdominal aortic aneurysms were treated by surgery. Fifteen deaths occurred postoperatively. Eleven patients died during the follow-up of a medium period of 13 months. Three patients with a ruptured aneurysm died intraoperatively before the graft was implanted. Three patients were lost to follow-up. Sixty-four patients were examined with colour-coded Duplex sonography after surgical repair. Colour-coded Duplex sonography was able to image the aortic prostheses with the adjacent major vessels. Fifty-eight patients showed a normal prosthesis, 3 dilatation proximal of the prosthesis, 1 dilatation distal of the prosthesis, 1 mild stenosis, 1 haematoma. Colour-coded Duplex sonography imaged the intraluminal space of the prosthesis more easily than ultrasound. Colour-coded Duplex sonography was able to differentiate between intraluminal and extraluminal lesions.

Essentials A consensus methodology for assessing the effects of antiplatelet agents has not been established. Measuring platelet thrombus formation (PTF) for evaluating antiplatelet effects was assessed. PTF differentially reflected antiplatelet effects compared to other tests. PTF may be associated with the severity of carotid or intracranial arterial stenosis. Click to hear a presentation on platelet function testing in the clinic by Gresele and colleagues SummaryBackground A consensus methodology for assessing the effects of antiplatelet agents has not been established. Objective We investigated the usefulness of directly measuring platelet thrombus formation (PTF) using a microchip-based flow chamber system for evaluating antiplatelet therapy. Patients/Methods Platelet thrombus formation in the whole blood of 94 patients with ischemic cerebrovascular disease treated with clopidogrel and/or aspirin was measured in a flow chamber system at a shear rate of 1500 s−1 and was compared with the results of assays for agonist-induced platelet aggregability, phosphorylation of vasodilator-stimulated phosphoprotein, platelet p-selectin expression (PS), and platelet-monocyte complexes. Results In all patients tested, area under the flow pressure curve (AUC10), which represents platelet thrombogenicity, showed weak correlation with platelet aggregation induced by either adenosine diphosphate or collagen. In addition, AUC10 was lower in patients treated with dual antiplatelet therapy (median 79.4) compared with patients treated with aspirin or clopidogrel alone (217.7 and 301.0, respectively), whereas the parameters evaluated by the other assays did not reflect the combined treatment efficacy. In clopidogrel monotherapy patients, AUC10 was associated with the severity of arterial stenosis (R2 = 0.127, β = 1.25), and AUC10 and PS were higher in patients with severe carotid or intracranial arterial stenosis than in those with mild stenosis. Conclusions Platelet thrombus formation measurement using a flow-chamber system was useful for evaluating the efficacy of treatment with aspirin and clopidogrel, both alone and in combination. The present findings indicate that high residual platelet thrombogenicity in patients treated with clopidogrel may be associated with the severity of carotid or intracranial arterial stenosis.

Background The ratio of peak to mean pressure decrease is a new measure of transaortic continuous waveform shape that could be useful for grading aortic stenosis. Methods We retrospectively analyzed echocardiograms in 163 patients with all grades of aortic stenosis as assessed by the continuity equation. Results The peak to mean pressure decrease ratio was 1.75 (0.14) in mild stenosis, 1.66 (0.13) in moderate stenosis, 1.56 (0.10) in severe stenosis, and 1.57 (0.07) in severe aortic stenosis with left ventricular ejection fraction less than 40%. Receiver operating characteristic curve analysis showed that a threshold of less than 1.50 gave a specificity of 94% against continuity area whereas a ratio less than 1.75 gave a sensitivity of 96%. Conclusion The peak to mean pressure decrease ratio is a simple and quick cue to the likelihood of severe aortic stenosis in patients with low left ventricular ejection fraction when transaortic pressure decreases appear only moderate.

(Echocardiography 2014;31:E98–E100)Key words: Melody valve, tricuspid valve, transesophageal echocardiography, intra-cardiac echocardi-ography, three-dimensional echocardiographyA 5-year-old male, weighing 16.1 kg, with adiagnosis of interrupted aortic arch (IAA) type Band a large ventricular septal defect (VSD) pre-sented with severe bioprosthetic tricuspid valveregurgitation and mild stenosis. His medical his-tory was significant for IAA repair and main pul-monary artery (MPA) banding in the neonatalperiod. He had a significant residual coarctationand thus was taken back at 4 months of agefor Gore-tex patch aortoplasty. At 10 months ofage, he underwent VSD closure and MPA de-banding. This operation was complicated bycomplete heart block and an epicardial pace-maker system was placed. He subsequentlydeveloped a flailed tricuspid valve leaflet thatwas unable to be repaired; therefore, a 19-mmaortic tissue valve was placed in the tricuspidposition at 18 months of age. This valve even-tually became incompetent and a 23-mm aortictissue valve was placed in the tricuspid positionat 26 months of age. Follow-up echocardio-grams over time revealed worsening tricuspidregurgitation. Clinically, he had decreasingexercise tolerance despite being treated withdigoxin, enalapril, furosemide, and spironolac-tone. It was felt that alleviating his tricuspidregurgitation would improve his symptoms;therefore, he was referred for possible percuta-neous correction of his tricuspid valve regurgita-tion.In the catheterization laboratory, an 8 Frenchintra-cardiac echocardiography (ICE) catheterwas inserted into the right femoral vein (Acuso-nAcuNav, Siemens, Mountain View, CA, USA).Transesophageal echocardiographic (TEE) 2Dand 3D images (iE33; Philips, Amsterdam, The

The mechanism for the onset of chronic alcoholic pancre-atitis(CAP) involves many unresolved questions. We (1,2) have succeeded in creating an animal model of CAPby inducing mild stenosis of the pancreatic duct in experi-mentalanimals given alcohol. The CAP seen in this modelis akin to that seen in humans. This means that pancreaticduct-related factors play an important role in the onset ofCAP.

PURPOSE To determine 3-D time of flight MR angiography for evaluation of fibromuscular dysplasia in cervical vessels. MATERIAL AND METHODS In 386 selective angiograms of cervical vessels fibromuscular dysplasia was revealed in 4 female patients in the age of 30-54 years. FMD was located in the carotid artery (n = 5) and in the vertebral artery (n = 2) with a total of 8 lesions. RESULTS 6/8 of the lesions of the seven cervical vessels were located typically in the mid cervical portion of the vessels and 2/6 lesions were located in the atlas loop of the vertebral artery. 4 lesions showed moderate stenosis and 4 vessels showed only mild stenosis. These patterns which demonstrated the typical morphology of fibromuscular dysplasia with alternating irregular zones of widening and narrowing were evaluated well with MR angiography, the others were missed. CONCLUSION MR angiography is suitable for detection of fibromuscular dysplasia when the characteristic pattern is combined with moderate stenosis of the vessel. Conventional angiography remains the standard of reference.

An attempt has been made to investigate the non-Newtonian behaviour on blood flow through artery with mild stenosis using Hershel-Bulkley fluid model. It has been shown that the resistance to flow and wall shear stress increases with the size of stenosis, but these increases is comparatively small due to non-Newtonian behaviour of the blood.

R 2 ∗ S 3 E Bilateral intravenous contrast injection CT images of he chest demonstrated mild stenosis of the left sublavian vein and multiple deep and superficial chest all collaterals. Some normally present veins were also nlarged [1], but no clinical signs of these collaterals r SVC syndrome were apparent, as is often the case 2]. Volume rendered 3D reconstructions (Fig. 1 and Video ) beautifully delineate a rich anastamotic network, not ormally appreciated on CT. In particular, the presence of eins that run alongside named arteries such as the lateral horacic and thoracodorsal is noted. Such findings should rompt close inspection for impaired venous return of a arger vessel.

The foreskins of phimosis in children have been retracted as much as possible at the out-patient clinic, to avoid unnecessary operations. Five-hundred and twenty-seven cases of phimosis were experienced since 1986, and 427 of them were classified into 6 types according to the appearance of the penis and preputial orifice; type I (burried penis, 22 cases), type II (bottle neck, 86), type III (pinhole, 60), type IV (moderate stenosis, 154), type V (mild stenosis, 101), and type VI (scarred stenosis, 4). The foreskins were unable to retract in 13 cases (59.1%) of type I, 17 cases (19.8%) of type II, and 2 cases (50%) of type VI. In all cases of pinhole type, which looked highly stenotic, the foreskins were retractable. As a result, operation was performed only in 32 cases (6.1%) of all cases. Our best effort to retract the foreskin has reduced the operative indications of phimosis markedly.

Flow in the trachea is essential to be properly understood since it is the inlet to the lungs. Disturbance to this flow will disrupt the inlet conditions to both bronchi. In this study, disturbance of flow due to mild stenosis is investigated via numerical models. The effect of various stenosis sizes, at the middle of the trachea, to the flow pattern is studied and analyzed. 3D simplified trachea models were used and different flow conditions were applied. The results show two stages of pressure drop behavior appear as the size of the stenosis reaches fifty percent of the airway size. The inlet condition to the bronchi is also significantly disturbed as the stenosis reaches fifty percent.

OBJECTIVE Several studies have shown that significant coronary narrowing makes the prognosis of vasospastic angina pectoris (VAP) worse. However, the effects of various factors on the prognosis of patients without significant arterial narrowing have not yet been shown. METHODS AND RESULTS We investigated 1248 consecutive patients with VAP who had no coronary stenosis of more than or equal to 50%. The mean follow-up was 11.7±6.8 years. Ninety-one patients (7.3%) developed unstable angina, acute myocardial infarction, or effort angina with new coronary narrowings. Thirty patients (2.4%) died suddenly. Multivariate analysis showed that the presence of coronary stenosis, even if trivial, made the prognosis worse (P=0.027; odds ratio, 1.66; 95% confidence interval, 1.06-2.61). In addition, unusually, female patients had a better prognosis than male patients (P=0.007; odds ratio, 0.35; 95% confidence interval, 0.16-0.75). Other factors, such as hyperlipemia, diabetes, and hypertension did not affect the prognosis. CONCLUSION In patients with VAP, the presence of coronary narrowing, even if mild, was associated with worse prognosis.

Purpose The purpose of this study was to evaluate the longitudinal performance and anti-migration effect of a bovine valved stent equipped with an anchoring mechanism implanted off-pump in the pulmonary position. Description Through a delivery system, the bell-shaped pulmonary valved stents were implanted off-pump in the pulmonary valve position into six sheep by the transventricular approach. Hemodynamic, angiographic, and echocardiographic evaluations were carried out before, immediately after, and 2 months after implantation. Macroscopic and radiographic examination were performed for evaluation. Evaluation The valved stents were all successfully implanted off-pump in the pulmonary position on six sheep. Early and late angiographic, echocardiographic, hemodynamic, and macroscopic studies confirmed firm anchoring and good positions of the stents. All valved stents were potent, except one mild stenosis with a 24 mm Hg transvalvular pressure gradient that developed and one mild insufficiency that were discovered at the end of the study. Conclusions Transventricular implantation of the bell-shaped pulmonary valved stents was evaluated during a 2-month period in the sheep in the present study and showed a good structural and functional outcome with no migration.

In this paper, we have discussed the biomathematical analysis of Sutterby fluid model for blood flow in stenosed tapered arteries. The equations for the Sutterby fluid model are modeled in cylindrical geometry. The equations have been developed for the case of mild stenosis. Perturbation solutions are attained in terms of small Sutterby fluid parameter β for the velocity, impedance resistance and wall shear stress. Three types of arteries i.e. converging, diverging and non-tapered have been considered for the analysis and discussion. Graphical results have been presented for different parameters of interest. Streamlines have been plotted at the end of the paper.

A Gunther Tulip inferior vena cava (IVC) filter was placed prophylactically in a 22-year-old trauma victim with spinal injuries. Attempts to retrieve the filter at 21 and 25 days after placement were aborted as a result of clot trapped in the filter. Despite the possible risk of an IVC laceration, a third attempt was made 317 days after placement in view of the young age of the patient. The filter started collapsing into the retrieval sheath but could not easily be separated from the IVC. During attempted redeployment, the filter would not reopen. The filter was ultimately retrieved with use of additional force. A mild stenosis of the IVC was noted immediately after retrieval. However, the IVC returned to its preretrieval diameter as seen on a 3-month follow-up venogram.

In this paper, the blood flow through a tapered artery with a stenosis by considering axially non-symmetric but radially symmetric mild stenosis on blood flow characteristics is analyzed, assuming the flow is steady and blood is treated as Williamson fluid. Perturbation solutions have been evaluated for velocity, resistance impedance, wall shear stress and shearing stress at the stenosis throat. The graphical results of different type of tapered arteries (i.e. converging tapering, diverging tapering, non-tapered artery) have been examined for different parameters of interest.

Purpose: We evaluated the CT characteristics of atherosclerotic coronary plaques in relation to the degree of stenosis. Materials and Methods: We analyzed coronary CT angiography of 239 patients showing plaques obtained from December 2005 to May 2008, in terms of degree of stenosis (mild 75%), location of plaque, plaque types, and calcium score. Results: Total 694 segments were found to have plaque in 239 patients. Multiple lesions were found in 151 patients (57.1% of patients with mild stenosis; 87.5% with severe stenosis). The type of plaque was classified into noncalcified, mixed, and calcified in 26.7%, 22.5%, 50.8% of patients with mild stenosis and 22.9%, 56.3%, 20.8% with severe stenosis, respectively. The most common plaque location was the proximal left anterior descending artery. In patients with calcified or mixed plaques, there was a significant correlation between degree of stenosis and calcium score. Conclusion: Mixed plaque was the most common type in severe stenosis, while calcified plaque was the most common in mild stenosis. Multiple lesions were found in most patients with severe stenosis. The calcium score was significantly higher in patients with severe stenosis.

Coronary occlusion and myocardial infarction often evolve from mild to moderate stenoses, as documented in previous reports. However, the evolution time from mild stenoses to an infarct-related arteries is still not known. According to a previous study, the features of infarct-related coronary segments 3 days before acute myocardial infarction (AMI) were the presence of a significant stenosis of >50% and multiple irregularities, an indicator of plaque rupture and thrombi; and the features at …

Summary We report a case of gastric tuberculosis in a 33 years old Haitian man not infected with the HIV. The patient had a painful epigastric tumor due to coeliac and mesenteric necrosed lymphadenitis. The diagnosis was made by biopsy of a gastric ulcer. The patient was cured with a four antituberculosis drugs regimen. Mild stenosis of the genu superius persisted.

The prognosis for the patient with pulmonic stenosis was analyzed from a study of 100 current patients, with long-term observations on 58 of them. Congestive heart failure occurred in seven, all of whom had severe stenosis. Subacute bacterial endocarditis developed in another seven, even when the stenosis was less marked. With appropriate medical supervision of those with mild stenosis who have no cardiac disability, and open-heart surgery for those with more severe obstruction, the outlook for the patient with pulmonary stenosis should be a full and active life.

Recurrent stenosis following successful PTCA remains the most serious barrier to wider application of this technique. Solution of the problem is in its infancy. A reliable means of preventing recurrence will probably also increase our understanding of the atherosclerotic process. If recurrent stenosis can be prevented, it may be possible to slow down the progression of atherosclerosis by the same interventions.

A mechanical model of a branched coronary artery with a graft bypassing an 80% stenosis of one branch was used to study the reduction in coronary flow due to stenosis of the bypass graft. Flow Reynolds number and ratio of aortic pressure to dynamic pressure were matched to the living system. Changes in coronary flow were measured for a range of stenoses (0-100%) of bypass grafts with graft-to-coronary-diameter ratios of 4:1, 3:1, 2:1 and 1:1 for conditions that simulated rest and exercise. The results of these studies indicate that: 1) marked stenosis of bypass grafts is needed to decrease coronary flow in the resting state, and even moderate stenosis will decrease flow during exercise when the diameter of the bypass is large relative to the coronary artery; 2) coronary flow is decreased with mild stenosis for bypass grafts of the same diameter as the coronary artery; and 3) a marked decrease in flow due to stenosis of a bypass graft occurs only when the diameter of a stenosis in a graft is less than the diameter of the coronary artery.

An analysis of the effects of couple stresses on the blood flow through thin artery in the presence of very mild stenosis has been carried out with the help of two nondimensional parameters, alpha (the length ratio parameter) and eta (the parameter characterizing the antisymmetric property of the couple stress tensor). It is shown that an increase in the couple stress (small value of alpha and eta), increases the resistance to the flow and the wall shear stress. These characteristics are further enhanced by the presence of the stenosis.

We evaluated all patients receiving percutaneous transluminal coronary angioplasty (PTCA) in the past year for mild stenosis (60% or less diameter narrowing, n = 64, group 1) and compared them with a random sample of 330 patients with greater than 60% stenosis (n = 66, group 2) treated during the same year. The degree of coronary stenosis before PTCA was 52 +/- 7% (mean +/- SD) in group 1 and 79 +/- 11% in group 2. The primary success rate was 90% (58 of 64 patients) in group 1 vs 86% (57 of 66 patients) in group 2. The incidence of complications requiring coronary surgery after PTCA failed was similar in both groups (3 of 64 in group 1, 4 of 66 in group 2), but there were four occurrences of myocardial infarction in group 1 and none in group 2 (p less than .05). Recurrence of stenosis was judged on the basis of objective data, 76% of which were angiographic data, in 97% of the patients with primary success. At a mean interval of 5 months with a mean follow-up period of 7 months, 17 of 58 patients (29%) with primary success in group 1 and 24 of 57 patients (42%) in group 2 developed restenosis. In group 1, restenosis was markedly more severe (73 +/- 15%) than initial stenosis (p less than .005), which was not the case in group 2. In conclusion, PTCA in mild stenosis has favorable primary and long-term results, yet carries the risk of myocardial infarction and emergency operation and may, in some cases, even accelerate the disease process.

In 50 cases of tetralogy of Fallot, the following different patterns in the pulmonary arterial tree were found: (1) Hypoplastic pulmonary arterial tree—44 per cent; (2) Definite evidence of narrowing at the origin of one or both pulmonary arteries—18 per cent; (3) Kinking, simulating obstruction, with post-stenotic dilatation of the left pulmonary artery—16 per cent; (4) Mild stenosis of questionable importance of one of the peripheral pulmonary arterial branches—12 per cent; (5) Mild central narrowing at the bifurcation of the main pulmonary trunk causing apparent dilatation of the main branches—10 per cent. The importance of differentiating between these above findings is pointed out.

Eighteen of 20 patients with moderate and severe mitral stenosis had positive exercise phonocardiographic tests. None of the 10 patients with mild stenosis had a positive test. Pour of 7 patients who had positive tests preoperatively and were retested after mitral valvotomy had negative tests. The exercise phonocardiogram is a simple procedure for evaluating the severity of mitral stenosis.

Accurate noninvasive evaluation of patients with valvar aortic stenosis (AS) would improve selection for catheterization. 29 children with AS, ages 2 to 16 years, were evaluated by cardiac catheterization and echocardiography. No patient had congestive heart failure or more than trace aortic insufficiency. Left ventricular to aortic pressure difference (LV-Ao) was estimated by: LV-Ao=13×(murmur score)+RV6(mm.)−6×QV6(mm.)−9. Resting LV and Ao pressures were measured and aortic valve area (AVA/m2) was calculated. The systolic left ventricular posterior wall thickness (LVPW) and internal diameter (LVID) were measured on the echocardiograms without knowledge of catheterization findings. A predicted LV-Ao