Search PubMed⌕ Search

Biomedical subjects

Frank A Flachskampf

Publications and source records attributed to Frank A Flachskampf.

At least 19 recordsLinked to original sources
PubMed2006

Do women have impaired regional systolic function in hypertensive heart disease? A 3-dimensional echocardiography study.

AIMS: In pressure overload left ventricular (LV) hypertrophy, gender-related differences in global LV systolic function have been previously reported. The goal of this study was to determine regional systolic function of the left ventricle in male and female patients with hypertensive heart disease. METHODS AND RESULTS: Regional LV function was analyzed from multiplane transesophageal echocardiography with three-dimensional (3D) reconstruction of the left ventricle. In 24 patients (13 males and 11 females), four parallel (2 basal and 2 apical) equidistant short axis cross-sections from base to apex were obtained from the reconstructed LV. In each short axis 24 wall-thickness measurements were carried out at 15 degrees intervals at end-diastole and end-systole. Thus, a total of 192 measurements were obtained in each patient. Wall thickening was calculated as difference of end-diastolic and end-systolic wall thickness, and fractional thickening as thickening divided by end-diastolic thickness. Fractional thickening and wall stress were inversely related to end-diastolic wall thickness in both, males and females. Females showed less LV systolic function when compared to males (p<0.001). However, when corrected for wall stress, which was higher in females, there was no gender difference in systolic function. CONCLUSION: There are regional differences in LV systolic function in females and males which are directly related to differences in wall stress. Thus, gender-related differences in LV regional function are load-dependent and not due to structural differences.

Female↗
PubMed2006

Recommendations for chamber quantification.

Quantification of cardiac chamber size, ventricular mass and function ranks among the most clinically important and most frequently requested tasks of echocardiography. Over the last decades, echocardiographic methods and techniques have improved and expanded dramatically, due to the introduction of higher frequency transducers, harmonic imaging, fully digital machines, left-sided contrast agents, and other technological advancements. Furthermore, echocardiography due to its portability and versatility is now used in emergency rooms, operating rooms, and intensive care units. Standardization of measurements in echocardiography has been inconsistent and less successful, compared to other imaging techniques and consequently, echocardiographic measurements are sometimes perceived as less reliable. Therefore, the American Society of Echocardiography, working together with the European Association of Echocardiography, a branch of the European Society of Cardiology, has critically reviewed the literature and updated the recommendations for quantifying cardiac chambers using echocardiography. This document reviews the technical aspects on how to perform quantitative chamber measurements of morphology and function, which is a component of every complete echocardiographic examination.

Cardiac Volume↗
PubMed2006

The standard TEE examination: procedure, safety, typical cross-sections and anatomic correlations, and systematic analysis.

Multiplane transesophageal echocardiography (TEE) is a semi-invasive, very low-risk imaging procedure utilizing the upper gastric and esophageal echo windows to image the heart with the use of high-frequency transducers. It allows for high spatial resolution and access to structures that are routinely not well seen by transthoracic echocardiography, such as the left atrial appendage, the thoracic aorta, and the pulmonary veins, or where transthoracic imaging may be insufficient to answer a specific question, such as the presence of small vegetations, endocarditic abscesses, abnormalities of the interatrial septum, and others. Another important indication is the ventilated patient or the patient in the operating room, where transthoracic echocardiography is unrewarding or impossible. A particular role has emerged for TEE for identifying candidates for mitral valve repair by providing detailed functional and morphologic information on the diseased valve and by checking intraoperatively the results of surgery. A set of cross-sections, defined by anatomic landmarks, has been compiled, which can be systematically sought, evaluated, and modified according to the clinical question in order to extract the maximal information from TEE.

Echocardiography, Transesophageal↗
PubMed2006

Assessment of aortic dissection and hematoma.

Aortic dissection and aortic intramural hematoma are highly lethal diseases occurring mostly in patients with arterial hypertension or Marfan syndrome. Transesophageal echocardiography (TEE) is the diagnostic imaging procedure of choice in the unstable patient. Hallmarks of dissection are the presence of an intimal membrane, or flap, dividing a true and a false lumen, entry and reentry tears, periaortic hematoma, pericardial effusion or tamponade, and aortic regurgitation in dissection of the ascending aorta. TEE allows detection of involvement of the ascending aorta, which places the patient in an extremely high-risk group and necessitates urgent operation. The accuracy of TEE is similar to computed tomography and magnetic resonance imaging, with the added benefit of being feasible at the bedside or in the operating room. Precautions have to be taken during TEE to avoid an abrupt rise in blood pressure. Aortic intramural hematoma is often a precursor of classic dissection or accompanies it and can also be diagnosed by TEE, although the diagnosis is frequently difficult.

Aortic Dissection↗
PubMed2005

Three-dimensional echocardiography: rational mode of component images for left ventricular volume quantitation.

Three-dimensional echocardiography (3DE) improves the accuracy of left ventricle (LV) volumetry compared with the two-dimensional echocardiography (2DE) approach because geometric assumptions in the algorithms may be eliminated. The relationship between accuracy of mode (short- versus long-axis planimetry) and the number of component images versus time required for analysis remains to be determined. Sixteen latex models simulating heterogeneously distorted (aneurysmatic) human LVs (56-303 ml; mean 182+/-82 ml) were scanned from an 'apical' position (simultaneous 2DE and 3DE). For 3DE volumetry, the slice thickness was varied for the short (C-scan) and long axes (B-scan) in 5-mm steps between 1 and 25 mm. The mean differences (true-echocardiographic volumes) were 16.5+/-44.3 ml in the 2DE approach (95% confidence intervals -27.8 to +60.8) and 0.6+/-4.0 ml (short axis; 95% confidence intervals -3.4 to +4.6) as well as 2.1+/-9.9 ml (long axis; 95% confidence intervals -7.8 to +12.0) in the 3DE approach (in both cases, the slice thickness was 1 mm). Above a slice thickness of 15 mm, the 95% confidence intervals increased steeply; in the short versus long axes, these were -6.5 to +8.5 versus -7.0 to +10.6 at 15 mm and -10.1 to +15.7 versus -11.3 to +10.9 at 20 mm. The intra-observer variance differed significantly (p<0.001) only above 15 mm (short axis). Time required for analysis derived by measuring short-axis slice thicknesses of 1, 15, and 25 mm was 58+/-16, 7+/-2 and 3+/-1 min, respectively. The most rational component image analysis for 3DE volumetry in the in vitro model uses short-axis slices with a thickness of 15 mm.

Cardiac Volume↗
PubMed2005

Transradial stenting of the iliac artery: a case report.

In this case report, stenting of the common iliac artery via the radial access route with 6 Fr equipment, including an extra long multipurpose catheter, is presented. Radial access avoids bleeding and ischemia that may complicate retrograde or crossover access to the iliac artery.

Angioplasty, Balloon↗
PubMed2005

Influence of ultrasound operating parameters on ultrasound-induced thrombolysis in vitro.

The effect of operating parameters on the thrombolytic potency of ultrasound (US) is important for potential therapeutic applications, but is not fully understood. Fresh human whole-blood thrombi were exposed in vitro to focused US from a diagnostic transducer driven by an impulse generator via an amplifier to vary duration (10 to 60 min), intensity (7 to 90 W/cm(2)), frequency (2 to 4.5 MHz), pulsed wave duty cycle (1:5 to 1:100 and continuous wave mode) and pulse length (100 to 400 micros). Segments of thrombi (498 +/- 73 mg) were submersed and insonated in saline solution. Thrombolytic efficiency was expressed as percentage loss of mass compared with controls (noninsonified thrombi). Ultrasound exposure achieved a significantly higher thrombolysis than no US, 56 +/- 16 % vs. 29 +/- 11 % (n = 232, p < 10(-6)). There was an exponential saturation-type correlation with duration of insonation (r(2) = 0.64) and intensity (r(2) = 0.97), an inverse correlation with US frequency at matched intensities (r(2) = 0.76, p < 10(-5)), a logarithmic relationship with duty cycle in pulsed mode (r(2) = 0.86) and a modest direct effect of pulse length (r(2) = 0.57, p < 10(-5)). Thus, thrombolytic efficiency of US depends directly on duration, intensity, duty cycle and pulse length and inversely, on frequency.

Case-Control Studies↗
PubMed2004

Assessment of coronary remodeling in stenotic and nonstenotic coronary atherosclerotic lesions by multidetector spiral computed tomography.

OBJECTIVES: This study was designed to investigate whether contrast-enhanced multidetector spiral CT (MDCT) permits assessment of remodeling in coronary atherosclerotic lesions. BACKGROUND: With sufficient image quality, MDCT permits noninvasive visualization of the coronary arteries, but its ability to assess remodeling has not been evaluated. METHODS: Out of 102 patients in whom MDCT (16-slice scanner, intravenous contrast, 0.75-mm collimation, 420 ms rotation) was performed before invasive coronary angiography, 44 patients with high-quality MDCT data sets showing atherosclerotic plaque in a proximal coronary artery segment were chosen for evaluation. In multiplanar reconstructions orthogonal to the coronary artery, the cross-sectional vessel area was measured for the respective lesion and for a reference segment proximal to the lesion. The "Remodeling Index" was calculated by dividing the vessel area in the lesion by the reference segment. Results were correlated to the presence of stenosis (>50% diameter reduction) in invasive angiography. In a subset of 13 patients, MDCT measurements were verified by IVUS. RESULTS: Reference vessel area was not significantly different between nonstenotic versus stenotic lesions (20 +/- 8 mm(2), n = 23 vs. 22 +/- 8 mm(2), n = 21). The mean Remodeling Index was significantly higher in nonstenotic than in stenotic lesions (1.3 +/- 0.2 vs. 1.0 +/- 0.2, p < 0.001). In five stenotic lesions, "negative remodeling" (Remodeling Index < or = 0.95) was observed. Cross-sectional vessel areas and Remodeling Indices measured by MDCT correlated closely to IVUS (r(2) = 0.77 and r(2) = 0.82, respectively). CONCLUSIONS: Multidetector spiral CT may permit assessment of remodeling of coronary atherosclerotic lesions in selected data sets of sufficient quality.

Coronary Angiography↗
PubMed2004

Are there sex differences in regional systolic function and wall stress in hypertrophic obstructive cardiomyopathy? A three-dimensional echocardiography study.

OBJECTIVES: Sex-related differences in left ventricular (LV) systolic function have been previously reported in patients with aortic stenosis and hypertensive heart disease. The goal of this study was to determine systolic function of the LV in male and female patients with hypertrophic obstructive cardiomyopathy and to relate it to wall thickness and wall stress, respectively. BACKGROUND: Wall thickening, a parameter of regional systolic function, is determined by wall thickness and wall stress. A comprehensive analysis of regional LV function was performed from multiplane transesophageal echocardiography with 3-dimensional reconstruction of the LV. METHODS: In 21 patients (11 men and 10 women) 4 parallel (2 basal and 2 apical) equidistant short-axis cross sections from base to apex were obtained from the reconstructed LV. In each short axis, 24 wall-thickness measurements were carried out in 15-degree intervals at end-diastole (ED) and end-systole. Thus, a total of 192 measurements were obtained in each patient. Wall thickening, a parameter of regional systolic function, was calculated as the difference of ED and end-systolic wall thickness, and fractional thickening as thickening divided by ED thickness. RESULTS: Fractional thickening and wall stress were inversely related to ED wall thickness in both men and women. Women showed better LV systolic function when compared with men (P <.001). However, when corrected for wall stress, which was lower in women, there was no sex difference in systolic function. CONCLUSIONS: There are regional differences in LV systolic function in men and women that depend on regional wall thickness and wall stress.

Cardiomyopathy, Hypertrophic↗
PubMed2004

Comparison of deformation imaging and velocity imaging for detecting regional inducible ischaemia during dobutamine stress echocardiography.

AIMS: To determine whether Doppler based myocardial tissue velocity imaging (TVI) or strain rate imaging (SRI) is more accurate in detecting stress-induced ischaemia during dobutamine stress echocardiography (DSE). METHODS AND RESULTS: Regional myocardial velocity, displacement, strain rate and strain patterns during DSE were investigated in 44 routine patients with known or suspected coronary artery disease. Simultaneous perfusion scintigraphy defined regional ischaemia. Curves and curved-M-mode patterns were analysed and receiver-operating-characteristics of TVI and SRI parameters were compared by their area under the curve (AUC) in the receiver-operating-characteristics. In non-ischaemic segments, peak systolic velocity and strain rate increased significantly. Unlike SRI, TVI parameters had higher values in basal than in apical segments. In 47 segments of 19 segments DSE-induced ischaemia, which was proven by scintigraphy. In ischaemia, velocity and strain rate increased less. Post-systolic shortening (PSS) was always seen in SRI but not regularly in TVI. Peak systolic velocity and systolic displacement were the best TVI-parameters of stress-induced ischaemia (AUC 0.68 and 0.77, respectively.), in SRI it was the ratio of PSS and maximal segmental deformation (AUC=0.95, p < 0.0001). CONCLUSION: Compared to TVI, SRI parameters showed no major apico-basal gradient and had significantly higher diagnostic accuracy, comparable to conventional reading. SRI thus appears superior to TVI for regional ischaemia detection during DSE and may be preferred to support conventional DSE reading.

Blood Flow Velocity↗
PubMed2003

Strain-rate imaging during dobutamine stress echocardiography provides objective evidence of inducible ischemia.

BACKGROUND: Interpretation of dobutamine stress echocardiography (DSE) is subjective and strongly dependent on the skills of the reader. Strain-rate imaging (SRI) by tissue Doppler may objectively analyze regional myocardial function. This study investigated SRI markers of stress-induced ischemia and analyzed their applicability in a clinical setting. METHODS AND RESULTS: DSE was performed in 44 patients with known or suspected coronary artery disease. Simultaneous perfusion scintigraphy served as a "gold standard" to define regional ischemia. All patients underwent coronary angiography. Segmental strain and strain rate were analyzed at all stress levels by measuring amplitude and timing of deformation and visual curved M-mode analysis. Results were compared with conventional stress echo reading. In nonischemic segments, peak systolic strain rate increased significantly with dobutamine stress (-1.6+/-0.6 s-1 versus -3.4+/-1.4 s-1, P<0.01), whereas strain during ejection time changed only minimally (-17+/-6% versus -16+/-9%, P<0.05). During DSE, 47 myocardial segments in 19 patients developed scintigraphy-proven ischemia. Strain-rate increase (-1.6+/-0.8 s-1 versus -2.0+/-1.1 s-1, P<0.05) and strain (-16+/-7% versus -10+/-8%, P<0.05) were significantly reduced (both P<0.01 compared with nonischemic). Postsystolic shortening (PSS) was found in all ischemic segments. The ratio of PSS to maximal segmental deformation was the best quantitative parameter to identify stress-induced ischemia. Compared with conventional readings, SRI curved M-mode assessment improved sensitivity/specificity from 81%/82% to 86%/90%. CONCLUSIONS: During DSE, SRI quantitatively and qualitatively differentiates ischemic and nonischemic regional myocardial response to dobutamine stress. The ratio of PSS to maximal strain may be used as an objective marker of ischemia during DSE.

Coronary Angiography↗
PubMed2003

Practicability and limitations of enhanced external counterpulsation as an additional treatment for angina.

BACKGROUND: An increasing number of clinical studies indicates reduction of angina and myocardial ischemia by enhanced external counterpulsation (EECP) therapy. However, given the wide range of contraindications and the long duration of treatment, eligibility and practicality issues have not been addressed systematically. HYPOTHESIS: Of all candidates for EECP (patients with drug-refractory angina without possibility of revascularization), the majority either have contraindications or have practical problems complying with the time demands that this therapy imposes. In the rest, EECP leads to satisfactory results. METHODS: During 18 months, every consecutive patient with angina despite medical and interventional therapy was evaluated for EECP at one center. Treated patients underwent a bicycle exercise test and perfusion imaging before and after the standard course of 35 h of EECP. In addition, patients were asked about frequency of angina and nitroglycerin usage before and after EECP, and all patients filled out a final questionnaire 1 year after the end of therapy. RESULTS: Overall, 48 patients were considered candidates for EECP. Of these, 24 were excluded for medical reasons: poor ejection fraction (4), peripheral artery disease (4), anticoagulation (4), and atrial fibrillation (3). Eight further patients declined EECP for lack of time or accommodation. Another 3 of the 16 remaining patients dropped out because of side effects. In the 13 patients who finished the treatment course, weekly anginal episodes were reduced by 48% (p < 0.05), on-demand nitroglycerin puffs were reduced by 51% (p < 0.05), work capacity was improved by 22% (p < 0.05), and the number of reversible perfusion defects in perfusion scans decreased nonsignificantly (-28%). However, 4 of 13 treated patients determined 1 year later that the detriment of loss of time exceeded the benefits of EECP. CONCLUSION: Similar to previous reports, our study confirms the reduction of angina and improvement of work capacity after EECP. However, using established contraindications, approximately two-thirds of patients considered to be candidates had to be excluded, and one-third of the treated patients regarded EECP therapy retrospectively as too time consuming.

Angina Pectoris↗
PubMed2003

Incidence and characteristics of segmental postsystolic longitudinal shortening in normal, acutely ischemic, and scarred myocardium.

OBJECTIVE: Myocardial longitudinal shortening after aortic valve closure (postsystolic shortening [PSS]) is considered a marker of pathology with diagnostic potential. However, PSS can also occur in healthy subjects. We, therefore, investigated the occurrence and characteristics of PSS in control subjects and patients, and how to distinguish normality from disease. METHODS: In 20 young control subjects, 10 older control subjects, 30 patients with acute myocardial infarction (acute ischemia), and 10 patients with postischemic myocardial scar, longitudinal myocardial deformation was measured with Doppler tissue strain rate (SR) imaging. Segmental SR and strain were visually and quantitatively analyzed and compared. RESULTS: In young control subjects, PSS was found in 98 of 313 segments (31%) and showed gaussian distribution (median 1.3%). During ejection time, median peak SR was -1.4 s(-1) and median strain -16.6%. In older control subjects, parameters differed only slightly. In acutely ischemic and scarred myocardium, both systolic strain and SR were significantly reduced or inverted. In disease, PSS occurred significantly more often (78% and 79%, respectively), was significantly higher in magnitude, and its peak occurred later than in young and older control subjects. CONCLUSION: PSS is a normal finding in healthy subjects occurring in approximately one-third of myocardial segments and, thus, is not always a marker of disease. Our data indicate that pathologic PSS can be detected by coexisting reduction in systolic strain and, second, by exceeding a postsystolic strain magnitude cutoff.

Echocardiography, Doppler, Color↗
PubMed2002

Direct coronary stenting versus predilatation followed by stent placement.

Direct stenting without antecedent dilatation may reduce procedural time, costs, and radiation exposure, and may result in less vessel injury. The purpose of this investigation was to compare immediate and long-term clinical and angiographic outcomes of direct stenting with stent placement after initial balloon dilation. Three hundred thirty-five symptomatic patients with single or multiple coronary lesions (diameter reduction 60% to 95%) of < or =30 mm length and with a vessel diameter of 2.5 to 4.0 mm were randomized either to direct stenting (group A, n = 171) or stenting after predilation (group B, n = 164). Patients with vessels with excessive calcification, severe proximal tortuosity, or occlusion were excluded. All patients were asked to return for routine repeat angiography at 6 months, irrespective of symptoms. Feasibility of direct stenting was 95% in group A, with 5% requiring crossover to predilation. Successful stent placement after predilation was performed in all 164 patients in group B. Direct stenting was associated with less procedural duration (group A 42.1 +/- 18.7 minutes vs group B 51.5 +/- 23.8 minutes, p = 0.004), radiation exposure time (group A 10.3 +/- 7.7 minutes vs group B 12.5 +/- 6.4 minutes, p = 0.002), amount of contrast dye used (group A 163 +/- 69 ml vs group B 197 +/- 84 ml, p <0.0001), and lower procedural costs (group A 845 +/- 167 vs group B 1,064 +/- 175, p <0.0001). Immediate angiographic results and in-hospital clinical outcomes (death, Q-wave myocardial infarction, repeat revascularization) were not significantly different between both strategies. However, at 6-month follow-up, direct stenting was associated with a lower angiographic restenosis (group A 20% vs group B 31%, p = 0.048) and target lesion revascularization rates (group A 18% vs group B 28%; p = 0.03). This study demonstrates the feasibility, safety, and outcomes of direct stenting in eligible coronary lesions. In appropriately selected cases, direct stenting has a lower rate of angiographic restenosis up to 6 months after the procedure, resulting in fewer coronary reinterventions compared with the conventional strategy of stenting with antecedent dilatation.

Aged↗
PubMed2002

Sequential vs. kissing balloon angioplasty for stenting of bifurcation coronary lesions.

Coronary angioplasty of bifurcation lesions remains a technical challenge and is believed to result in low procedural success associated with the risk of side-branch occlusion. Furthermore, long-term results are associated with a high rate of reintervention. The aim of the study was to evaluate the immediate and long-term clinical and angiographic results of sequential vs. simultaneous balloon angioplasty (kissing balloon technique) for stenting of bifurcation coronary lesions. Between December 1999 and January 2001, 59 patients underwent coronary angioplasty because of symptomatic bifurcation lesions type III (i.e., side branch originates from within the target lesion of the main vessel, and both main and side branch are angiographically narrowed more than 50%). Twenty-six patients were treated with simultaneous and 33 patients with sequential balloon angioplasty. Main-vessel stent placement was mandatory; side-branch stenting and platelet IIb/IIIa antagonists were allowed at the discretion of the operator. Kissing balloon technique offered no advantage in terms of procedural success or need for repeat target vessel revascularization due to restenosis at 6-month follow-up. Using sequential balloon angioplasty, permanent or transient side-branch compromise rate (TIMI flow < 3) was significantly higher than after kissing balloon technique (33% vs. 0%, respectively; P = 0.003). Major clinical events in-hospital or at 6-month follow-up, however, showed no significant differences. Kissing balloon angioplasty reduces the rate of transient side-branch occlusion compared to sequential PTCA but does not improve immediate or long-term outcome compared to sequential PTCA for stenting of bifurcation lesions.

Aged↗