Preliminary marked increase in the national organ donation rate in Israel following implementation of a new organ transplantation law.

Israel's organ donation rate has always been among the lowest in Western countries. In 2008 two new laws relevant to organ transplantation were introduced. The Brain-Respiratory Death Law defines the precise circumstances and mechanisms to determine brain death. The Organ Transplantation Law bans reimbursing transplant tourism involving organ trade, grants prioritization in organ allocation to candidates who are registered donors and removes disincentives for living donation by providing modest insurance reimbursement and social supportive services. The preliminary impact of the gradual introduction and implementation of these laws has been witnessed in 2011. Compared to previous years, in 2011 there was a significant increase in the number of deceased organ donors directly related to an increase in organ donation rate (from 7.8 to 11.4 donors per million population), in parallel to a significant increase in the number of new registered donors. In addition the number of kidney transplantations from living donors significantly increased in parallel to a significant decrease in the number of kidney transplantations performed abroad (from 155 in 2006 to 35 in 2011). The new laws have significantly increased both deceased and living organ donation while sharply decreasing transplant tourism.

Determinants of micro-embolic signals in patients with atherosclerotic plaques of the internal carotid artery.

BACKGROUND AND PURPOSE: This study aimed to investigate the embolic potential of carotid plaques, employing both the presence and the rate of micro-embolic signals (MESs), based on the presence and timing (current or past) of symptoms, degree of stenosis and ultrasonic characteristics of plaques. METHODS: We used the transcranial Doppler (TCD) to monitor MES and the Doppler ultrasound to classify carotid plaques in newly symptomatic (acute stroke or transient ischaemic attack (TIA)), formerly symptomatic (relevant stroke or TIA per anamnesis) and asymptomatic patients with internal carotid artery (ICA) stenosis. RESULTS: Stroke-related arteries evidenced a significantly greater presence of MES than the TIA-related and asymptomatic arteries (p=0.04), with no significant difference found between the latter two groups (stroke: 42/90, 46.7%; TIA: 15/49, 30.6%; asymptomatic: 40/130, 30.8%). Adjustment for anti-platelet treatment did not change this finding. The degree of stenosis, ultrasonic characteristics of texture and the density of plaques were not found to be associated with the presence or quantity of MES. CONCLUSION: MESs are present significantly more often in stenosed, stroke-related carotid arteries as compared with TIA-related or asymptomatic arteries. Neither the ultrasonic characteristics nor the degree of stenosis were found to influence the presence or rate of MES.

Multicenter evaluation of a self-expanding carotid stent system with distal protection in the treatment of carotid stenosis.

PURPOSE: Carotid artery stent placement may be limited by the embolization of atheromatous material. We evaluated the safety and feasibility of the Medtronic Self-Expanding Carotid Stent (Exponent) in combination with the Medtronic Interceptor Carotid Filter System for the treatment of carotid stenosis among patients at high risk for carotid endarterectomy. METHODS: Patients at high risk for carotid endarterectomy but amenable to percutaneous treatment with stent placement were enrolled. Clinical follow-up was performed at 30 days and 6 and 12 months postprocedure. The National Institutes of Health Stroke Scale was assessed before and within 3 days postprocedure and at 30 days and 6 months postprocedure. Angiography was performed pre- and postprocedure, and carotid duplex scans were performed at baseline and at 30 days and 6 months. RESULTS: Fifty-two carotid procedures were performed in 51 patients (mean age, 69 years; 84% of patients were men). The major adverse event (MAE) rate (death, stroke, and myocardial infarction [MI]) at 30 days was 5.9%: 2 strokes and a single death from periprocedural MI. MAE rates after 6 and 12 months were 5.9% and 11.8%, respectively. The delivery success rate was 94.2% (49/52) for the Interceptor Filter System and 95.9% (47/49) for the Exponent Stent. The mean diameter stenosis of the target lesion was reduced from 62.4% preprocedure to 21.2% postprocedure. CONCLUSION: High delivery success rates were achieved with a low rate of MAE (death, stroke, or MI) in a high-risk population. Treatment of carotid artery disease with the Exponent Carotid Stent combined with distal protection from the Interceptor Filter System is effective and safe.

Interindividual heterogeneity in the hypoxic regulation of VEGF: significance for the development of the coronary artery collateral circulation.

BACKGROUND: The coronary artery collateral circulation may be beneficial in protecting against myocardial ischemia and necrosis. However, there is a tremendous interindividual variability in the degree of new collateral formation in patients with coronary artery disease. The basis for this interindividual heterogeneity is not understood. In this study we test the hypothesis that failure to generate collateral vessels is associated with a failure to appropriately induce with hypoxia or ischemia the angiogenic factor, vascular endothelial growth factor (VEGF). METHODS AND RESULTS: We correlated the VEGF response to hypoxia in the monocytes harvested from patients with coronary artery disease with the presence of collaterals visualized during routine angiography. We found that there was a highly significant difference in the hypoxic induction of VEGF in patients with no collaterals compared with patients with some collaterals (mean fold induction 1.9+/-0.2 versus 3.2+/-0.3, P<0.0001). After subjecting the data to ANCOVA, using as covariates a number of factors that might influence the amount of collateral formation (ie, age, sex, diabetes, smoking, hypercholesterolemia), patients with no collaterals still have a significantly lower hypoxic induction of VEGF than patients with collaterals. CONCLUSIONS: This study provides evidence in support of the hypothesis that the ability to respond to progressive coronary artery stenosis is strongly associated with the ability to induce VEGF in response to hypoxia. The observed interindividual heterogeneity in this response may be due to environmental, epigenetic, or genetic causes. This interindividual heterogeneity may also help to explain the variable angiogenic responses seen in other conditions such as diabetic retinopathy and solid tumors.

Bypass surgery versus stenting for the treatment of multivessel disease in patients with unstable angina compared with stable angina.

BACKGROUND: Earlier reports have shown that the outcome of balloon angioplasty or bypass surgery in unstable angina is less favorable than in stable angina. Recent improvements in percutaneous treatment (stent implantation) and bypass surgery (arterial grafts) warrant reevaluation of the relative merits of either technique in treatment of unstable angina. Methods and Results- Seven hundred fifty-five patients with stable angina were randomly assigned to coronary stenting (374) or bypass surgery (381), and 450 patients with unstable angina were randomly assigned to coronary stenting (226) or bypass surgery (224). All patients had multivessel disease considered to be equally treatable by either technique. Freedom from major adverse events, including death, myocardial infarction, and cerebrovascular events, at 1 year was not different in unstable patients (91.2% versus 88.9%) and stable patients (90.4% versus 92.6%) treated, respectively, with coronary stenting or bypass surgery. Freedom from repeat revascularization at 1 year was similar in unstable and stable angina treated with stenting (79.2% versus 78.9%) or bypass surgery (96.3% versus 96%) but was significantly higher in both unstable and stable patients treated with stenting (16.8% versus 16.9%) compared with bypass surgery (3.6% versus 3.5%). Neither the difference in costs between stented or bypassed stable or unstable angina ($2594 versus $3627) nor the cost-effectiveness was significantly different at 1 year. CONCLUSIONS: There was no difference in rates of death, myocardial infarction, and cerebrovascular event at 1 year in patients with unstable angina and multivessel disease treated with either stented angioplasty or bypass surgery compared with patients with stable angina. The rate of repeat revascularization of both unstable and stable angina was significantly higher in patients with stents.

Aortic diameter and pressure-flow sequence identify mechanism of blood flow during external chest compression in dogs.

Aortic flow and pressure relations and aortic diameter were examined during sinus rhythm, internal cardiac massage, vest cardiopulmonary resuscitation, conventional manual cardiopulmonary resuscitation and high impulse manual cardiopulmonary resuscitation in 14 anesthetized large dogs. During sinus rhythm and during internal cardiac massage, ascending aortic flow and pressure increased simultaneously and the rise in ascending aorta pressure preceded the rise in descending aortic pressure by (mean +/- SEM) 28 +/- 4 and 30 +/- 1 ms, respectively. In contrast, during vest, conventional and high impulse cardiopulmonary resuscitation, ascending aortic flow lagged behind the initial rise in aortic pressure by 40 +/- 4 to 46 +/- 4 ms and ascending and descending aortic pressure increased simultaneously (p less than 0.001 for each external compression mode versus sinus rhythm and internal massage). The ratio of pulse pressure to stroke volume increased by an order of magnitude during all modes of external chest compression (p less than 0.001 versus sinus rhythm and internal massage) and aortic diameter decreased during vest and high impulse cardiopulmonary resuscitation (p less than 0.05 versus sinus rhythm and internal massage). The hemodynamics of external chest compression depart from the normal physiologic sequence of stroke volume-induced increase in aortic pressure and diameter. The rise in aortic pressure precedes flow into the aorta, stroke volume does not fully account for pulse pressure, and aortic diameter decreases during chest compression. These data support the hypothesis that blood flow is due to fluctuations in intrathoracic pressure for high impulse as well as vest and conventional cardiopulmonary resuscitation.

Intrathoracic and abdominal pressure variations as an efficient method for cardiopulmonary resuscitation: studies in dogs compared with computer model results.

Intrathoracic pressure variations are currently proposed as the main flow-generation mechanisms in standard and modified cardiopulmonary resuscitation (CPR) techniques. A method of changing pressure within the thorax and abdomen without any degree of heart compression was developed and tested in dogs. Intrathoracic and abdominal pressure waves were induced by cyclic inflation and deflation of the lungs and of perithoracic and periabdominal balloons. Various modes of CPR, depending on the rate of cycling, the use of a periabdominal balloon inflation, and a delay between the abdominal and thoracic pressure waves, were studied during ventricular fibrillation. During artificial systole (high intrathoracic pressure phase), the pressure which developed in the right ventricle (96.7 +/- 20.5 mmHg) was higher than the pressure in the aorta (89.3 +/- 20.5 mmHg, p less than 0.001). In artificial diastole (low intrathoracic pressure phase), the right ventricular pressure (11.7 +/- 2.6 mmHg) was lower than the aortic pressure (17.5 +/- 3.3 mmHg, p less than 0.001). The average flow in the carotid artery was 21.7 +/- 7.8 ml . min-1, which was 18 +/- 6% of the baseline carotid flow before CPR. Three different factors were found to improve the efficiency of CPR: periabdominal balloon inflation simultaneous with the intrathoracic pressure waves; increased frequency of the pressure waves from 60 to 100 cycles per minute; and inflation of the periabdominal balloon 50 to 100 ms before the thoracic balloon. Blood-gas and acid-base balance analysis during CPR revealed well-oxygenated arterial blood with a marked respiratory alkalosis and a slowly developing metabolic acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Augmentation of cardiac output and carotid blood flow by chest and abdomen phased compression cardiopulmonary resuscitation.

Phased compression cardiopulmonary resuscitation, whereby the chest and abdomen are compressed sequentially, is a new approach to the classical cardiopulmonary resuscitation technique, which is based on the compression of the chest alone. Six dogs with cardiac arrest were treated by external chest and abdominal compression using a rigid plexiglas suit lined with flexible perithoracic and periabdominal bladders. Fast inflation and deflation of the two independent bladders, together with forced ventilation of the lung, generated phased pressure pulses. The physiological variables monitored throughout the experiment included central venous, left ventricular, and central arterial pressures, carotid blood flow, cardiac output, and acid base balance. The phased compression technique was performed with phased time lags of 0, 150, 300, 400, 600, 700, and 850 ms between the abdominal and thoracic pressure pulses. A random sequence of the different phased compression modes, each lasting for 3-10 minutes, was applied during the prolonged resuscitation procedure that lasted for up to 70 minutes. By starting the abdominal compression 300-400 ms before the thoracic compression the carotid flow index improved by 77% (from 13% with simultaneous compression to 23% with phased compression) and the cardiac output index increased by 65% (from 7.8% with simultaneous compression to 12.5%). The results provide insight into the chest pump concept and the role of intrathoracic and intra-abdominal pressures in generating improved blood circulation during cardiopulmonary resuscitation, and show the advantages of phased compression over chest compression alone and simultaneous chest and abdominal compression.

Effect of interconnecting collagen fibres on left ventricular function and intramyocardial compression.

OBJECTIVE: The aim was to study the effects of the collagen mesh that interconnects the myocardial fibres on left ventricular mechanics and intramyocardial pressure. METHODS: An earlier model which integrates a symmetrical left ventricular geometry and transmural muscle fibre structure with muscle fibre mechanics was expanded to include radial stiffness generated by dynamically stretched radial collagen fibres. The calculated end systolic pressure-volume relationship (ESPVR) was compared to left ventricular pressure and volume data from six open chest dogs, obtained over a wide load range. Midwall intramyocardial pressure measurements by flat intramyocardial transducer in six different dogs were also used. RESULTS: Consistent with the experiments, inclusion of radial stiffness yielded an ESPVR that was more curvilinear than the collagen-free model, and modified global left ventricular function in that the end systolic volume increased. A diastolic suction effect, manifested by a negative pressure with a steep diastolic pressure-volume relationship at low end systolic volumes, was predicted. The intramyocardial pressure was higher than the left ventricular pressure at the end of isovolumetric relaxation, when radial stretch is maximal and fibre stresses are relaxed. This is attributed to the radial fibre stress component. Intramyocardial pressure was only weakly dependent on left ventricular cavity pressure under wide load manipulations at constant contractility. The experiments also confirmed model predictions that (1) peak intramyocardial pressure is insensitive to load, (2) intramyocardial pressure is markedly higher than left ventricular pressure at the end of isovolumetric relaxation, and (3) intramyocardial pressure continues to rise during ejection towards a maximum value near end ejection. CONCLUSIONS: The transverse radial stiffness due to radial collagen interconnections between myocardial fibrils affects the global systolic left ventricular function, the diastolic suction effect, and the mechanism of systolic coronary compression.

Effect of hyper- and hypovolaemia on regional myocardial oxygen consumption.

STUDY OBJECTIVE - The purpose of the investigation was to study the effect of preload on coronary blood flow and myocardial oxygen consumption in subendocardial and subepicardial regions of left ventricular free wall. DESIGN - Ventricular volume in anaesthetised open chest dogs was altered over a range of 20% to produce hypovolaemia (10-15% exsanguination) or hypervolaemia (colloid infusion), allowing measurements of regional blood flow and oxygen consumption with varying preloads. beta Adrenergic blockade was used to limit changes in inotropy, and heart rate was kept constant by pacing at 150 beats.min-1. SUBJECTS - 9 mongrel dogs of either sex weighing 24.9 (SEM 4.1) kg were studied. MEASUREMENTS and RESULTS - Left ventricular volume was calculated from ultrasonic measurements of long and short axis end diastolic diameters and wall thickness. Regional myocardial blood flow was estimated using radioactive microspheres, and oxygen consumption in each region was determined from microspectrophotometric measurements of oxygen saturations in small arteries and veins. Hypervolaemia increased subepicardial blood flow from 66.8(6.9) (normovolaemic) to 114.1(13.5) ml.min-1.100 g-1, and regional oxygen consumption from 4.08(0.57) to 6.44(1.08) ml.min-1.100 g-1. Values in the subendocardium were similar, except for oxygen consumption, which increased less than in the subepicardium. Left ventricular end diastolic volume, pressure, and output were each increased in hypervolaemia, but not dP/dt and systolic aortic pressure. Hypovolaemia reduced blood pressures without reducing end diastolic volume. CONCLUSIONS - Augmented flow work produced by increased preload (even in the absence of changes in pressure work) increases myocardial oxygen supply equally in the subepicardium and the subendocardium, while oxygen extraction and consumption are preferentially augmented in the subepicardium.

Radionuclide ventriculography and central aorta pressure change in noninvasive assessment of myocardial performance.

Systolic pressure-volume diagrams were obtained noninvasively by measuring the systolic central aortic pressure with a new device and by combining the pressure measurements, thus obtained, with absolute volume measurements obtained by radionuclide ventriculography during ejection. By dividing the peak power by the time elapsed from the beginning of ejection to the peak power point, the ejection rate of change of power (ERCP) was calculated. The ability of this index to assess left ventricular function at rest and exercise was evaluated in ten healthy subjects. ERCP proved to be more sensitive than global left ventricular ejection fraction increasing fivefold from rest to exercise compared with only 20% increase in global ejection fraction. ERCP increased dramatically postexercise from 3411 +/- 2173 to 18,162 +/- 14,633 gm/sec2, median 12,750, 95% confidence interval 9700-29,600, in healthy, while in patients it increased twofold from 2637 +/- 824 to 5062 +/- 1897 gm/sec2, median 4070, 95% confidence interval 2800-7030, p less than 0.001. ERCP had an excellent discriminative power in differentiating healthy subjects from patients, having 100% sensitivity, 90% specificity, 95% accuracy, 95% positive predictive value, and 90% negative predictive value. Thus, this noninvasive index seems to have a more comprehensive ability to evaluate changes in left ventricular function and shows a promising potential for clinical applications.

Acute and 30-day results of the serpentine balloon expandable stent implantation in simple and complex coronary arterial narrowings.

We report the acute and 30-day results with a new serpentine-design, tubular, stainless steel, balloon-expandable stent (beStent) in the first 100 patients. One hundred forty-eight stents were used to treat 103 narrowings in the left anterior descending (n = 46), left circumflex (n = 20), and right coronary (n = 37) arteries. There were 85 de novo and 18 restenotic lesions (lesion length: < 10 mm [31], 10 to 20 mm [43] > 20 mm [29]; lesion type: A [10] B1 [29], B2 [20], C [44]; total occlusions, 23. More than 1 stent was used in 31 patients for treatment of long lesions that could not be covered by 1 stent. The stents used were 15-mm (n = 106), 25-mm (n = 38), or 35-mm (n = 4) long. Stent implantation strategy involved predilatation, deployment, and high-pressure dilatation, using the same balloon if possible. Clinical in-hospital success was 97% (2 patients had stent thrombosis that was recanalyzed, with myocardial infarction developing in 1, and 1 patient died on day 14 from retroperitoneal bleeding treated with surgery and complicated by sepsis). One-month event-free survival was 96%, with 1 death on day 21 due to hypertensive crisis. There were no other major adverse cardiac events in this first complex cohort of patients. In conclusion, the initial experience with this stent demonstrates its safety and efficiency for treating simple and complex coronary disease, with a relatively low rate of complications. Long-term clinical follow-up awaits further investigation.

Haptoglobin phenotype as a predictor of restenosis after percutaneous transluminal coronary angioplasty.

We have demonstrated that a genetic polymorphism in the antioxidant protein haptoglobin is important in determining which patients develop restenosis after percutaneous transluminal coronary angioplasty. Knowledge of the haptoglobin phenotype may be useful in the assessment and utilization of new therapies to reduce restenosis, particularly in patients who are homozygous for the haptoglobin 2 allele.

Magnetic resonance imaging as a noninvasive standard for the quantitative evaluation of left ventricular mass, ischemia, and infarction.

Because magnetic resonance imaging (MRI) acquires data in a spatially unambiguous fashion and the three-dimensional interrelationships of one image plane to another are easily ascertained, there are far fewer technical restrictions imposed on this method than on other imaging techniques. Furthermore, the multiplanar nature of MRI image acquisition, in any plane desired, is a feature unique to this imaging technology. MRI is thus well suited to the highly accurate quantification of global and regional left ventricular (LV) size and function, and can be used as a standard for comparison to other techniques, once validated. Because the determination of LV mass by MRI requires no assumptions about ventricular shape, it should be well suited to the evaluation of both normal hearts and those distorted by infarction. We performed gated MRI on 15 dogs before and after myocardial infarction. LV mass was calculated with 5 short axis planes. The correlation was excellent between actual mass before infarction and after MI. Accuracy was similar for both end-diastole and end-systole. Thus, MRI accurately determines LV mass in both distorted and normal hearts. We have also developed a method for quantification and mapping of regional wall thickening throughout the LV as an index of regional ischemia by utilizing the 3D geometry to calculate the perpendicular wall thickness of a 3D volume element of tissue. This 3D volume element results in less variability of normal wall thickening and provides a better discriminator of ischemic from nonischemic zones in a canine model of acute ischemia, whereas there is considerably greater overlap between ischemic and normal zones with standard planar MRI techniques. The 3D method is more accurate than planar methods in avoiding biases resulting from the oblique course of an image plane through the LV wall, resulting in better distinction of ischemic from nonischemic tissue. Finally, the accurate assessment of regional LV function for the identification of ischemic or infarcted myocardium has been enhanced greatly by a new technique, myocardial tissue tagging, in which an electronic marker is applied to the myocardium which persists through ejection, enabling the accurate tracking of specific areas of the heart as they move and rotate through the cardiac cycle.

The "jaundiced heart": a possible explanation for postoperative shock in obstructive jaundice.

Patients with obstructive jaundice are susceptible to postoperative shock and kidney failure. The cause of these potentially fatal complications has not been fully clarified. The present study was designed to assess the role of myocardial dysfunction in the hemodynamic disturbance of obstructive jaundice. We studied the effect of isolated cholemia on left ventricular performance in five conscious dogs before and 2 weeks after choledochocaval anastomosis by using measurements of systolic time intervals (STIs) and maximal dp/dt. Mean left ventricular ejection tiem (LVET) decreased after cholemia from 159 +/- 2.8 msec to 139 +/- 2.6 msec (p less than 0.005), while mean preejection period (PEP) and mean PEP/LVET were increased from 41 +/- 8.5 msec to 87 +/- 14 msec (p less than 0.05) and from 0.39 +/- 0.06 to 0.62 +/- 0.1 (p less than 0.01), respectively. During cholemia, STIs were unchanged after intravenous administration of ouabain, whereas in the control period, there was shortening of mean PEP from 71 +/- 8.8 msec to 58 +/- 7.6 msec (p less than 0.05) and of Q-S2 from 257 +/- 12 msec to 235 +/- 14 msec (p less than 0.005) in response to ouabain. Maximal dp/dt decreased after choledochocaval anastomosis from 4543 +/- 593 mm Hg/sec to 3666 +/- 648 mm Hg/sec (p less than 0.025). We conclude that cholemia in the dog is clearly associated with impaired left ventricular performance. The present data also support a previously published in vitro study from our laboratory showing that cholemia blunts the myocardial contractile response to sympathomimetic agents. The cardiodepressor effect of cholemia may explain the increased tendency of patients with obstructive jaundice to postoperative shock and renal failure.

Septal/free wall curvature ratio: a noninvasive index of pulmonary arterial pressure.

The leftward septal shift, a well-recognized feature of pulmonary hypertension, was used to quantify right ventricular pressure in 16 patients with pulmonary hypertension and 11 control patients, all with normal left ventricular function. Pulmonary pressure was calculated from the tricuspid regurgitation jet and left ventricular pressure was taken by arm cuff measurements. Short-axis echocardiographic images were obtained and the midwall curvatures of the septum and the left ventricular free wall were measured for each frame from end diastole to end systole and averaged. The septal/free-wall curvature ratio (CR) was 0.37 +/- 0.19 in the study group compared with 0.79 +/- 0.06 in the control group (p < 0.0001). A tight relationship between the CR and the transseptal/transmural pressure ratio (CR = 0.057 + 0.89 x transseptal/transmural pressure ratio; r = 0.98; p < 0.001) was obtained by linear regression. Given the systolic arterial pressure, the pulmonary systolic pressure is given by: systolic arterial pressure x (1.064-1.12 x CR). Therefore the CR can be used as a noninvasive index that reflects the level of pulmonary pressure in relationship to the systolic arterial pressure.

Digital subtraction myocardial contrast echocardiography: design and application of a new analysis program for myocardial perfusion imaging.

Myocardial contrast echocardiography may provide important physiologic information on myocardial perfusion. Most current analysis programs use manual frame grabbing and selecting of the area of interest. This is time-consuming and not highly reproducible. A system for automatic analysis of myocardial contrast echocardiographic studies was developed and evaluated. The program acquires an electrocardiographically gated sequence of end-diastolic images with a frame grabber in a personal computer. The baseline image is subtracted and the videodensity versus time contrast curve parameters are calculated on-line. Fast color-coded analysis is done automatically with a running square window that covers the entire image. A second mode of contrast analysis allows manual selection of multiple regions of interest. The program was evaluated with contrast echo data from open-chest dogs and two demonstrative patients. This myocardial contrast analytic package is an inexpensive, rapid, flexible, convenient, and reproducible on-line method that facilitates myocardial contrast echocardiographic analysis.

Discrimination between healthy and diseased hearts by spectra decomposition of their left ventricular three-dimensional geometry.

A quantitative procedure for 3-D shape analysis of human LVs (left ventricles,) studied in vivo by 3-D computed tomography is introduced. The procedure utilizes the geometrical cardiogram signal for characterizing the 3-D shape of the studied LV, and uses spectral decomposition to obtain the corresponding feature vectors needed for automatic classification. It was found that the different pathological states of the LV were associated with characteristic changes in the geometrical spectrum domain. Representing each heart by a feature vector in the spectral domain and applying unsupervised fuzzy clustering of the obtained 27 feature vectors, an overall success of 85% in classification was obtained. These results indicate that an operator-independent shape-based diagnosis is potentially feasible for the four different pathological categories studied.

Acute and chronic effects of self-expanding nitinol stents in porcine coronary arteries.

BACKGROUND: There is a paucity of experimental data regarding self-expanding stents. This study evaluated the acute and chronic effects of CardioCoil, a self-expanding nitinol coil stent, in porcine coronary arteries. METHODS: Twenty-three self-expanding nitinol stents were implanted without associated balloon angioplasty in normal coronary arteries of 12 pigs, which were serially sacrificed up to 6 months. Angiographic and histologic analyses were performed to evaluate the deployment characteristics, patency rates, neointimal response, and unique features of the self-expanding nature of the CardioCoil stent. RESULTS: All stents were successfully deployed and remained patent acutely. Three undersized stents migrated proximally and there was one episode of subacute thrombosis in an oversized stent. The remaining stents were patent throughout the survival period and neointimal responses were favorable for up to 6 months (all mean neointima < 200 microns up to 6 months). There was evidence of continuing stent expansion over time (stent diameter 2.85 +/- 0.78 mm immediately after deployment and 3.24 +/- 0.97 mm at follow-up) and the majority of stent struts were in the adventitia by 6 months. Re-endothelization occurred starting one week after implantation and was complete by 8 weeks. CONCLUSIONS: This study shows that the CardioCoil self-expanding nitinol coil stent, is associated with favorable deployment characteristics and patency rates, although appropriate sizing is more crucial than with balloon-expandable stents. More importantly, there appears to be a "dissociation' between the deep vessel wall injury by the chronic strut expansion process and the neointimal reaction, unlike balloon-expandable stents.

One-year clinical follow-up with the serpentine balloon expandable stent: report of the first 100 patients.

BACKGROUND: We recently reported a high technical and 30-day clinical success rate among the first 100 patients treated with the tubular, serpentine design, stainless steel, balloon-expandable stent (beStent) in Israel. The present study examined the clinical results in these patients after the first year. METHODS: Seventy-eight men and 22 women were included in the study. Previous myocardial infarction, bypass surgery and percutaneous transluminal coronary angioplasty had occurred in 52%, 12% and 26% of the patients, respectively. Diabetes mellitus was present in 30 patients and hypertension in 34 patients. One hundred and forty-eight stents of 15, 25, and 35 mm lengths were used. The indications for stenting were suboptimal results (n = 85), bailout conditions (n = 10) or for the prevention of restenosis (n = 8), and lesion types were A (n = 10), B1 (n = 29), B2 (n = 20), and C (n = 44). All patients were clinically monitored with regular visits at 1, 3, 6, 9 and 12 months. RESULTS: Overall, the 12-month event-free survival rate was 82%. Subacute thrombosis occurred in two patients. There were two non-cardiac deaths, one O-wave myocardial infarction, six elective bypass surgeries and 12 target lesion revascularizations. Event-free survival was significantly higher for those with lesions shorter than 15 mm than for those with lesions longer than 15 mm (90% versus 67%, P = 0.003), and for women compared with men (96% versus 78%, P = 0.02). CONCLUSIONS: The initial experience with the beStent shows favorable long-term results with an overall event rate of 18% for this subset of relatively complex lesions; higher event rates were observed for longer lesions.