[Low flow/low gradient aortic valve stenosis : clinical and diagnostic management]. / "Low-Flow/Low-Gradient"-Aortenklappenstenose : Klinisches und diagnostisches Spektrum.

Low gradient aortic stenoses (AS) represent a special challenge for physicians with respect to an exact diagnosis and optimal therapy. The difficulty lies in the estimation of the severity of AS which is decisive for subsequent treatment and the prognosis. Low flow and low gradient can be due to systolic or diastolic dysfunction by high-grade as well as by medium-grade AS and be of non-valvular origin. The latter group is to be interpreted as pseudoaortic stenosis as long as the low flow can successfully be raised by interventional means. However, only patients in the first group can be expected to profit from valve replacement and for patients in the second group the accompanying diseases must be the focus of therapeutic treatment. Therefore, according to recent European surveys up to 30% of patients with severe AS are undertreated due to false estimation of the severity of stenosis and perioperative risk stratification. Furthermore, follow-up investigations have shown that patients with low flow/low gradient stenosis and borderline-normal ejection fraction (EF) are in an advanced stage of the disease because they have often developed a severe reduction in longitudinal myocardial function and in addition have pronounced myocardial replacement fibrosis due to cardiac remodelling despite a preserved EF. Therefore, aortic valve area, mean pressure gradient and EF alone cannot be taken into consideration for the management of patients with severe AS but a comprehensive assessment of the hemodynamics, such as stroke volume, special functional parameters as well as individual clinical appearance is essential for precise diagnostic and therapeutic decision making.

[Improved quality of coronary diagnostics and interventions by virtual reality simulation]. / Qualitätsverbesserung von Koronardiagnostik und -intervention durch "Virtual-Reality"-Simulation.

Currently, more than 800,000 diagnostic procedures and 300,000 percutaneous coronary interventions are performed annually in 556 catheter laboratories in Germany. These numbers document the importance of training programs in interventional cardiology. However, this need is in sharp contrast to the time constraints for continuing medical education in Germany due to personnel and financial restrictions. A possible solution for this dilemma could be new training programs which partially supplement conventional clinical training by simulation-based medical education. Currently five virtual reality simulators for diagnostic procedures and percutaneous coronary interventions are available. These simulators provide a realistic hands-on training comparable to flight simulation in aviation.The simulator of choice for a defined training program depending on the underlying learning objectives could either be a simple mechanical model (for puncture training) or even a combination of virtual reality simulator and a full-scale mannequin (for team training and crisis resource management). For the selection of the adequate training program the basic skills of the trainee, the learning objectives and the underlying curriculum have to be taken into account. Absolutely mandatory for the success of simulation-based training is a dedicated teacher providing feedback and guidance. This teacher should be an experienced interventional cardiologist who knows both the simulator and the selected training cases which serve as a vehicle for transferring knowledge and skills.In this paper the potential of virtual reality simulation in cardiology will be discussed and the conditions which must be fulfilled to achieve quality improvement by simulation-based training will be defined.

[Functional cardiac MRI for assessment of aortic valve disease]. / Aortenklappenstenose im MRT mit Dynamik und 3D.

Aortic valve disease shows a rising incidence with the increasing mean age of Western populations. The detection of hemodynamic parameters, which transcends the mere assessment of valve morphology, has an important future potential concerning classification of the severity of disease. MRI allows a non-invasive and a spatially flexible view of the aortic valve and the adjacent anatomic region, left ventricular outflow tract (LVOT) and ascending aorta. Moreover, the technique allows the determination of functional hemodynamic parameters, such as flow velocities and effective orifice areas. The new approach of a serial systolic planimetry velocity-encoded MRI sequence (VENC-MRI) facilitates the sizing of blood-filled cardiac structures with the registration of changes in magnitude during systole. Additionally, the subvalvular VENC-MRI measurements improve the clinically important exact determination of the LVOT area with respect to its specific eccentric configuration and its systolic deformity.

Implementing artificial insemination as an effective tool for ex situ conservation of endangered avian species.

Approximately 503 of the known species of birds are classified as 'endangered' or 'critical'. Captive propagation programs have proven useful in maintaining genetic diversity and restoring wild populations of certain species, including the Peregrine falcon, California condor and Whooping crane. Artificial insemination (AI) has the potential of solving problems inherent to reproductive management of small, closed populations of endangered birds, including dealing with demographic instability, physical and behavioral disabilities, sexual incompatibility, lack of synchrony, and need to maintain gene diversity. In this review, we address the necessary methods and factors that allow AI to be applied effectively to manage rare bird populations. It is clear that semen availability and quality are the greatest limiting factors to implementing consistently successful AI for birds. Behavioral sensitivity to animal handling and the ability to minimize stress in individual birds also are keys to success. Multiple, deep vaginal inseminations can improve fertility, particularly when semen quality is marginal. Laparoscopic methods of semen transfer also have produced fertile eggs. All of these practices leading to successful AI remain dependent on having adequate basic knowledge on female reproductive status, copulatory behavior, endocrine profiles and duration of fertility, especially as related to oviposition. The overall greatest challenge and highest priority is defining these normative traits, which are highly species-specific.

Contemplative meditation reduces ambulatory blood pressure and stress-induced hypertension: a randomized pilot trial.

A total of 52 pharmacologically untreated subjects with essential hypertension were randomly allocated to either 8 weeks of contemplative meditation combined with breathing techniques (CMBT) or no intervention in this observer-blind controlled pilot trial. CMBT induced clinically relevant and consistent decreases in heart rate, systolic and diastolic blood pressure if measured during office readings, 24-h ambulatory monitoring and mental stress test. Longer-term studies should evaluate CMBT as an antihypertensive strategy.

Use of intravascular ultrasound to compare effects of different strategies of lipid-lowering therapy on plaque volume and composition in patients with coronary artery disease.

BACKGROUND: We studied whether lipid-lowering therapy with atorvastatin (target LDL cholesterol [LDL-C] <100 mg/dL) compared with a moderate treatment regimen that used other lipid-lowering drugs led to a lesser progression of atherosclerosis and to different changes in plaque echogenicity in patients with coronary artery disease. METHODS AND RESULTS: This study was a 12-month, open-label, randomized, multicenter trial, which used serial 3D intracoronary ultrasound to calculate plaque volume and plaque echogenicity. After transcatheter therapy, 131 patients were randomized (atorvastatin n=65, usual care n=66). The target plaque had to be a minor lesion (ie, a diameter stenosis of <50% on angiography). After 12 months, mean LDL-C was reduced from 155 to 86 mg/dL in the atorvastatin group and from 166 to 140 mg/dL in the usual care group. Mean absolute plaque volume showed a larger increase in the usual care group compared with the atorvastatin group (usual care 9.6+/-28.1 mm(3), atorvastatin 1.2+/-30.4 mm(3); P=0.191). The hyperechogenicity index of the plaque increased to a larger extent for the atorvastatin group than for the usual care group, with a significant treatment effect for the percent change (atorvastatin 42.2%, usual care 10.1%; P=0.021). CONCLUSIONS: One year of lipid-lowering therapy to <100 mg/dL LDL-C most likely led to a slowdown of plaque growth of minor lesions. The significantly larger increase in plaque hyperechogenicity is most likely due to a change in plaque composition.

Reliability of quantitative coronary angiography of the target lesion immediately and 1 day after coronary balloon and excimer laser angioplasty.

OBJECTIVES: This prospective trial was performed to evaluate the impact of the morphologic complications of angioplasty on the reliability and results of quantitative angiographic assessment of the residual stenosis. BACKGROUND: Postintervention quantitative coronary analysis is limited by a variety of such complications. METHODS: In 199 patients undergoing an early control angiographic study within 24 h after coronary balloon or excimer laser angioplasty (24-h study), detailed quantitative angiographic measurements were performed on the target lesion immediately after intervention and at the 24-h study. Reproducibility of quantitative arteriography was determined by repeat measurements on the same angiogram. RESULTS: Intraobserver/interobserver variability was significantly higher (p < 0.0001/p < 0.03) for the postintervention angiogram than for the 24-h angiogram. Patients were classified into three subgroups with respect to the occurrence of angiographic complications or chest pain after intervention. In patients with angiographic complications after balloon angioplasty alone/stand-alone laser angioplasty/laser angioplasty with adjunctive balloon dilation, a significant difference in mean minimal lumen diameter (p = 0.0001/p = 0.03/p = 0.035) was observed between the immediate postintervention and 24-h angiogram. In patients without angiographic complications or patients with recurrent chest pain undergoing balloon angioplasty, stand-alone or adjunctive laser angioplasty, mean minimal lumen diameter remained nearly unchanged (p = NS). CONCLUSIONS: Angiographic measurements of the target lesion immediately after angioplasty were significantly less reliable than measurements obtained at 24 h after angioplasty in patients with angiographic complications. The occurrence of postintervention vascular complications was associated with significant early lesion changes between the immediate postangioplasty and the 24-h angiogram.

Influence of sampling site and flow area on cardiac output measurements by Doppler echocardiography.

In 40 patients cardiac output was simultaneously determined by pulsed Doppler echocardiography and thermodilution (range 4.0 to 10.2 liters/min). The sample volume was located in the center of the mitral anulus, at the tips of the mitral leaflets and in the center of the aortic anulus. Circular cross-sectional areas of the mitral anulus, aortic anulus and aortic bulbus were calculated from M-mode and two-dimensional echocardiographic diameters. The varying short axis of the elliptical mitral opening area was obtained from the diastolic leaflet separation in the M-mode, and the long axis was derived from the maximal mitral orifice area or mitral anulus diameter. Cardiac output was calculated by multiplying time-velocity integrals with the different areas and heart rate. Doppler flow measurements correlated significantly with the thermodilution method (r = 0.79 to 0.93). Flow measurements at the aortic anulus were most accurate (r = 0.93, SEE = 0.589 liter/min) if the annular area was derived from the M-mode tracing. Measurement of the anulus in the apical five chamber view yielded a significant underestimation and the area of the aortic bulbus provided an overestimation of cardiac output. Left ventricular inflow was underestimated at the mitral leaflet tips and overestimated at the mitral anulus. The accuracy of pulsed Doppler cardiac output measurements strongly depends on the assumed flow area and sampling site. Both should be determined at the same level in the inflow or outflow tract of the left ventricle. Measurement of cardiac output in the center of the aortic anulus provided the highest accuracy.

Accuracy of Doppler echocardiography in quantification of left to right shunts in adult patients with atrial septal defect.

In previous experimental and pediatric studies, the ratio of pulmonary to systemic flow (Qp/Qs) was accurately estimated by Doppler echocardiography in various cardiac shunt lesions. The purpose of this study was to assess the accuracy of pulsed Doppler echocardiography in determining the magnitude of shunt flow in adult patients with an ostium secundum type atrial septal defect. In 32 patients with high quality echocardiograms and excellent Doppler signals, blood flow was measured in the right and left ventricular outflow tract by Doppler echocardiography. In 16 patients without heart disease, the correlation (r) between systemic (Qs) and pulmonary (Qp) blood flow was 0.96 (SEE = 0.417 liter/min, y = 1.05x - 0.21) and the mean Qp/Qs ratio was 1.01 +/- 0.09. In 16 patients with an atrial septal defect, the Qp/Qs ration measured by oximetry ranged from 1.34 to 4.61 and by pulsed Doppler echocardiography from 1.31 to 4.46 (p = NS). In these 16 patients, the correlation between the Qp/Qs ratio determined by oximetry and pulsed Doppler echocardiography was significant (r = 0.82, SEE = 0.54). In the total group of 32 patients, the correlation was stronger (r = 0.93, SEE = 0.37). Systematic differences between the invasive and noninvasive shunt calculations did not occur. Thus, in adult patients with an atrial septal defect of the secundum type and high quality echocardiograms, the magnitude of left to right shunt can be accurately assessed by pulsed Doppler echocardiography. In the absence of pulmonary hypertension, pulsed Doppler echocardiography provides precise information for the decision to undertake conservative or operative treatment.

Pressure recovery in aortic stenosis: an in vitro study in a pulsatile flow model.

OBJECTIVES: This study was designed to study pressure recovery in various models of aortic valve stenosis by performing hemodynamic measurements under physiologic conditions in a pulsatile aortic flow circuit. The results were used to validate calculations of pressure recovery based on theoretic considerations derived from fluid dynamics. BACKGROUND: Pressure recovery in aortic stenosis has not been systematically analyzed. METHODS: Stenoses varying in size, shape (circular, Y-shaped, slitlike) and inlet configuration (sharp-edged, nozzle-shaped inlet, artificially stenosed bioprostheses) were used. Aortic pressures were measured at multiple sites distal to the stenotic orifice to determine pressure gradients and recovery. RESULTS: With decreasing orifice area (2, 1.5, 1 and 0.5 cm2) pressure recovery increased (5, 7, 10 and 16 mm Hg, respectively) and the index pressure recovery to maximal peak to peak gradient decreased (56%, 37%, 24% and 14%, respectively). For a given orifice size of 0.5 cm2, this index ranged between 12% for a Y-shaped orifice and 15% for a circular orifice with a nozzle (cardiac output 4 liters/min). Increasing the cardiac output increased pressure recovery, whereas the ratio of pressure recovery to maximal pressure gradient remained constant. CONCLUSIONS: The index pressure recovery to transvalvular pressure gradient, which expresses the hemodynamic relevance of pressure recovery, decreases with increasing severity of aortic stenosis but is independent of transvalvular flow. Thus, pressure recovery is of minor importance in severe aortic stenosis but may account for discrepancies between Doppler and manometric gradients observed in patients with mild to moderate aortic stenosis or a prosthetic valve in the aortic position.

Effect of exercise on valvular resistance in patients with mitral stenosis.

OBJECTIVES: This exercise study assessed the relation between valvular resistance and flow in patients with mitral stenosis. BACKGROUND: Valvular resistance has been proposed as an alternative measure of stenotic valvular lesions, which is speculated to remain stable under changing hemodynamic conditions. METHODS: In 35 of 40 patients with pure or predominant mitral stenosis, continuous wave Doppler measurements of the mitral stenotic jet were possible at rest and during supine bicycle ergometry. Simultaneously, transvalvular flow was assessed by thermodilution technique. For calculation of valvular resistance, the mean mitral valve pressure gradient was determined according to the simplified Bernoulli equation and divided by transvalvular flow. Additionally, effective mitral valve area was calculated according to the continuity equation method, dividing flow by the mean diastolic flow velocity. RESULTS: Valvular resistance was 65 +/- 32 dynes.s.cm-5 at rest and increased to 82 +/- 43 dynes.s.cm-5 at 25 W (p < 0.001). The most prominent increase in valvular resistance (rest to 25 W 63 +/- 28 to 95 +/- 48 dynes.s.cm-5, p < 0.001) was found in those patients who had no or only a moderate (< 20%) change in effective mitral valve area. In contrast, valvular resistance remained constant (67 +/- 36 vs. 70 +/- 32 dynes.s.cm-5) in patients with a significant (> or = 20%) increase in mitral valve area with exercise. CONCLUSIONS: In patients with mitral stenosis, the exercise-induced changes in valvular resistance are heterogeneous. This is the result of the variable response of mitral valve area to an increase in flow. In the individual patient, mitral valve area can significantly increase, a factor that has to be taken into account when interpreting the hemodynamic relevance of the obstruction. Calculated valvular resistance is flow dependent and has no advantage over valve area calculations for quantifying mitral stenosis.

Myocardial properties of the new dihydropyridine calcium antagonist isradipine compared to nifedipine with or without additional beta blockade in coronary artery disease.

Isradipine is a new dihydropyridine calcium antagonist with myocardial effects significantly different from those of nifedipine, as shown by in vitro and animal experimental data. Isradipine selectively inhibits the sinus node but not the atrioventricular conduction and its negative inotropic action is much less if administered in a dose of comparable peripheral effects. To study these effects in man, 40 patients with coronary artery disease were divided into 2 groups receiving either a continuous 30-minute intravenous infusion of 2 mg of nifedipine or 0.5 mg of isradipine, doses that resulted in a comparable afterload reduction (decrease of systemic vascular resistance: nifedipine -22.1%, isradipine -25%, p less than 0.001). Ten patients in each group received an additional intravenous bolus of 5 mg of propranolol at the end of the calcium antagonist administration to antagonize its induced adrenergic reflex mechanisms. The heart rate significantly increased after nifedipine only (+9.2%, p less than 0.001), experienced no change after isradipine and the nifedipine and propranolol combination and decreased after the combination of isradipine and propranolol (-9.6%, p less than 0.001). This resulted in a significant decrease of the rate pressure product with isradipine (-12.5%, p less than 0.001) but not with nifedipine. As a result of the afterload-induced adrenergic reflex mechanisms, the maximal derivative of the left ventricular pressure increased after isradipine administration (+13.5%, p less than 0.001) and was unchanged after nifedipine, which demonstrates the significantly less negative inotropic properties of isradipine as compared with nifedipine.

Initial angiographic results in ablation of atherosclerotic plaque by percutaneous coronary excimer laser angioplasty without subsequent balloon dilatation.

Percutaneous transluminal coronary excimer laser angioplasty was performed in 15 patients using a 1.3-mm diameter laser catheter. The catheter consists of 20 concentric quartz fibers of 100 microns diameter each located around a central lumen suitable for a 0.014-inch flexible guidewire. The catheter was coupled to an excimer laser delivering energy at a wavelength of 308 nm and at a pulsewidth of 60 ns. Quantitative analysis of the angiograms documented a decrease from 77 +/- 15% diameter stenosis before intervention to 40 +/- 22% after the first irradiation cycle and to 21 +/- 17% after termination of laser ablation. The minimal lumen diameter increased from 0.4 +/- 0.2 to 1.3 +/- 0.4 and to 1.6 +/- 0.4 mm, respectively. Vessel reocclusion was seen in 2 patients at 24-hour control angiography. No procedure-related major complications such as vessel perforation occurred. In 8 patients, however, intraluminal lucencies were seen, which were persistently visualized 24 hours after intervention in 6 patients. Despite pretreatment with intracoronary nitroglycerin, coronary spasm occurred in 8 patients and was reversible after additional sublingual vasodilator therapy. The results of this pilot study suggest that percutaneous coronary excimer laser angioplasty is feasible and effective for ablation of coronary lesions in selected patients and can be performed without subsequent conventional balloon angioplasty. The clinical impact of this new interventional technique, however, remains to be assessed.

Comparison of two mechanical ultrasound devices with and without echogenic contrast dye.

To evaluate the impact and limitations of intracoronary ultrasound, 64 segments of 13 isolated coronary arteries were examined and 2 mechanical devices (device A, 30 MHz 5Fr [CVIS] and device B, 20 MHz 4.8Fr [Diasonics/Boston Scientific] were compared with the corresponding histologic specimens. Luminal dimensions were assessed with and without echogenic contrast dye (Laevovist, Schering AG, Germany). After application of contrast dye, correlation of luminal area between histology and ultrasound was improved from r = 0.62 to r = 0.77 (device B; p < 0.05) and from r = 0.82 to r = 0.88 (device A; p = NS). Low accuracy of lumen measurements in segments < 2.5 mm could be improved by application of contrast dye. The number of quadrants in which wall thickness measurements were impossible was significantly higher for device B (n = 56; 22%) than for device A (n = 28; 11%); p < 0.01. This may be due to the different ringdown diameters of both systems (B, 2.6 mm; A, 2.0 mm; p < 0.0001). In assessing wall thickness only in segments of > 2.5 mm, a reliable correlation between ultrasound and histology was found (A, r = 0.80; B, r = 0.60). Sensitivity of plaque (n = 51) detection was lower for device B (63%) than for device A (82%, p < 0.05), and measurements correlated with histology only for device A. There are considerable differences in the accuracy of ultrasound measurements between mechanical systems. Nevertheless, additional application of contrast dye can improve accuracy of luminal measurements, especially in smaller vessels.

Evaluation of systolic performance by automated impedance cardiography.

Impedance cardiography (ICG) is a noninvasive method for evaluating cardiac function. Left ventricular stroke volume (SV) is the basic hemodynamic parameter derived from thoracic bioimpedance curves. Issues of our study were to investigate the diagnostic value of other indices of left ventricular systolic performance, such as ejection fraction (EF), index of contractility (IC), peak flow index (PFI), and acceleration index (ACI), which can also be calculated by ICG. Forty patients (PTS) with suspected coronary artery disease (CAD) were monitored by automated ICG during pharmacologic stress testing with dobutamine. All PTS underwent subsequent cardiac catheterization. In PTS with single vessel disease, the dobutamine-induced changes of SV, EF, IC, PFI, and ACI were comparable to those of PTS without CAD. In PTS with multivessel disease, the impaired systolic performance during dobutamine stimulation could be clearly demonstrated. We conclude that automated ICG is a useful method for monitoring SV and other indices of left ventricular systolic performance for detecting PTS with ischemic left ventricular dysfunction during cardiovascular stress.

Determination of right ventricular ejection fraction by thermodilution technique--a comparison to biplane cineventriculography.

Determination of right ventricular ejection fraction (RVEF) provides information about global right ventricular function, which may be important for the management of patients with various heart diseases. Right ventricular ejection fraction can be determined by new thermodilution techniques using fast-response thermistors. To evaluate the validity of these methods, thermodilution measurements were compared with biplane cineventriculography in 22 patients undergoing cardiac catheterization. In all patients standard deviation of RVEF was below 5%. Mean RVEF, determined by thermodilution, was 52% +/- 9%, ranging from 32% to 71% and correlated significantly with the results of angiography (RVEF: 52% +/- 9%) (r = 0.80, SEE +/- 5%, n = 22, p less than 0.001). Correlation was good especially in patients with small right ventricles (less than 160 ml) (r = 0.91, SEE +/- 5%, n = 13, p less than 0.001), lower heart rates (less than 65/min) (r = 0.84, SEE = +/- 6%, n = 12, p less than 0.001) and cardiac output below 5.51/min (r = 0.88, SEE +/- 6%, n = 11, p less than 0.001). Thus, if valid catheter placement is possible, right ventricular ejection fraction can be determined by thermodilution technique with good reproducibility and sufficient accuracy compared to biplane angio. Validation of this method in larger patient populations with various heart diseases is necessary.

Myocardial bridges at multiple sites over the left coronary artery in a patient with hypertrophic cardiomyopathy.

In a 47-year-old male with hypertrophic cardiomyopathy, coronary angiography revealed three myocardial bridges associated with significant systolic narrowing of the left coronary artery. Measurements during pacing and exercise demonstrated no sign of myocardial ischemia. Ten-year follow-up was uneventful. Thus, the prognosis of myocardial bridges, even when located at multiple sites across the left coronary artery, seems benign.

Evaluation of signal-averaged cardiokymography for the detection of ischaemic left ventricular dysfunction.

UNLABELLED: Cardiokymography (CKG) is a non-invasive method for the detection of patients with coronary artery disease (CAD). Issues of the present study were to evaluate the feasibility, sensitivity and specificity of a recently developed signal-averaged CKG system for detecting patients with pharmacologically induced ischaemic left ventricular wall motion abnormalities (WMA) during pharmacologic stress echocardiography (SE). Precordial CKG curves were recorded in 100 consecutive patients who underwent dobutamine-SE for suspected CAD. For interpretation, CKG curves were classified into three different types, depending on the degree of systolic outward motion. CKG test results were regarded as positive (indicating myocardial ischaemia) if there was a change of the baseline CKG type at peak pharmacologic stress. The CKG test results were positive in 18 of 27 patients with a pathologic dobutamine-SE (sensitivity 67%), but did not show any change of the prior CKG type in 57 of 69 patients with a normal SE (specificity 83%). Patients with a true positive CKG test had significantly (P<0.05) more echocardiographic segments with WMA than patients with a false negative CKG test. CONCLUSIONS: Signal-averaged CKG can detect patients with ischaemic ventricular dysfunction. Sensitivity of CKG in detecting patients with WMA depends on the extent of left ventricular ischaemia. Further studies are needed to define the diagnostic value of signal-averaged CKG in the non-invasive detection of patients with suspected CAD.

[Transvenous sonography of the peripheral arterial vessels. The initial clinical results]. / Transvenöse Sonographie peripherer arterieller Gefässe. Erste klinische Ergebnisse.

Intravascular ultrasound with 20 MHz/6.2-French transducer systems was used for arterial imaging via a transvenous approach. In 20 patients suffering from chronic arterial occlusive disease, 15 iliac arteries were evaluated during diagnostic angiography and 5 femoropopliteal arteries during balloon angioplasty (n = 3) and laser-assisted angioplasty (n = 2), respectively. Transvenous sonography did not allow differentiation of arterial wall layers and determination of vessel diameters as is usually possible during intraarterial sonography. Visualisation of iliac arteries was incomplete. In femoropopliteal vessels, guide wires could be detected within the arterial lumen but not in complete occlusions. Delivery of pulsed laser energy induced bright echoes near the catheter tip within a distance of 1-2 cm. Transvenous sonography is insufficient for monitoring of peripheral angioplasty; however, improved imaging quality might be possible at lower frequencies.

Long-term clinical course of patients with angina and angiographically normal coronary arteries.

In 88 of 103 consecutive patients with angina and normal coronary arteries, follow-up data could be achieved 6-11 years (9.2 +/- 1.2 years) after diagnostic left heart catheterization. Three of these patients died during follow-up (two noncardiac deaths and one death with no identifiable etiology). One patient suffered a documented myocardial infarction. In 40 patients (47%) chest pain diminished, while symptoms were unchanged in 20 (24%) or even worse in 25 (29%). Resolution or persistence of chest pain could not be predicted either by the character of pain (typical vs. atypical), the presence of hypertension, a left bundle-branch block, a positive exercise electrocardiogram or pathological pulmonary artery pressures during exercise, documentation of myocardial bridges, local wall motion abnormalities, or a left ventricular end-diastolic pressure greater than or equal to 13 mmHg. However, continuing chest pain was significantly more common in patients who revealed a 'slow-flow phenomenon' at initial coronary arteriogram. Thus, in patients with angina and normal coronary arteries the long-term course regarding frequency of morbid cardiac events is benign. However, more than half of the patients reported chest pain to be similar or even worse than at catheterization. Most clinical and invasive results at initial evaluation had no predictive value for the persistence of symptoms. The impact of 'slow-flow' in coronary arteriography, which was a phenomenon almost exclusive to patients with constant or even worse chest pain at follow-up, should be evaluated in larger patient populations.