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Objectives: This prospective cohort study in patients with aortic stenosis (AS) aimed to identify surrogates of myocardial fibrosis that are easy to derive in clinical practice, allow the differentiation of low-gradient severe AS from moderate AS, and have an impact on clinical outcome., Background: In patients with symptomatic aortic AS, a characteristic subgroup (i.e., up to one-third) exhibits severe AS with a concomitant low mean valve gradient either with preserved or reduced ejection fraction (EF). It is hypothesized that these patients tend to have an advanced stage of myocardial fibrosis and poor clinical outcome., Methods: Eighty-six patients with moderate or severe AS were examined by echocardiography including conventional aortic valve assessment, mitral ring displacement, and strain-rate imaging. Replacement fibrosis was quantified by late-enhancement magnetic resonance imaging. Biopsy samples were taken from patients with severe AS (n = 69) at aortic valve replacement. All patients were followed for 9 months., Results: Patients were divided into 4 groups according to aortic valve area (<1.0 cm(2)), mean valve gradient ≥40 mm Hg, and EF (<50%): group 1, moderate AS (n = 17); group 2, severe AS/high gradient (n = 49); group 3, severe AS/low gradient/preserved EF (n = 11); and group 4, severe AS/low gradient/decreased EF (n = 9). At baseline, a significant decrease in mitral ring displacement and systolic strain rate was detected in patients with low-gradient AS. In low-gradient groups, a higher degree of interstitial fibrosis in biopsy samples and more late-enhancement magnetic resonance imaging segments were observed. A close inverse correlation was found between interstitial fibrosis and mitral ring displacement (r = -0.79, p < 0.0001). Clinical outcome was best for patients in group 1, whereas mortality risk increased substantially in groups 2 through 4., Conclusions: In severe AS, a low gradient is associated with a higher degree of fibrosis, decreased longitudinal function, and poorer clinical outcome despite preserved EF. Mitral ring displacement differentiates between moderate AS and low-gradient/severe AS with preserved EF., (Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The Troponin in Planned PTCA/Stent Implantation With or Without Administration of the Glycoprotein IIb/IIIa Receptor Antagonist Tirofiban (TOPSTAR) trial investigated: 1) the amount of troponin T (TnT) release after nonacute, elective percutaneous coronary intervention (PCI) in patients pretreated with aspirin and clopidogrel; and 2) the effect of additional glycoprotein (GP) IIb/IIIa receptor inhibiton on postinterventional TnT release., Background: No data are available yet as to whether additional administration of a GP IIb/IIIa receptor antagonist might be beneficial in patients undergoing elective PCI already pretreated with aspirin and clopidogrel., Methods: After bolus application of the study medication (tirofiban [T] or placebo [P]), PCI was performed followed by an 18-h continuous infusion of T/P. Primary end point of the study was incidence and amount of TnT release after elective PCI after 24 h., Results: A total of 12 h after PCI troponin release was detected in 63% of the patients receiving P and in 40% of the patients receiving T (p < 0.05), after 24 h in 69% (P) and 48% (T) (p < 0.05) and after 48 h in 74% (P) versus 58% (T) (p < 0.08) of the patients. No differences were observed regarding major bleeding, intracranial bleeding or nonhemorrhagic strokes. After nine months a reduction of combined death/myocardial infarction/target vessel revascularization could be observed in the tirofiban group ([T] 2.3% vs. [P] 13.04%, p < 0.05)., Conclusions: Troponin T release occurs after successful intervention in 74% of the patients undergoing elective PCI after 48 h even after pretreatment with aspirin and clopidogrel. The GP IIb/IIIa receptor antagonist tirofiban is able to decrease the incidence of troponin release significantly in this patient population.

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.

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.

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.

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.

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.