Burkhard Sievers

Myocardial late gadolinium enhancement: prevalence, pattern, and prognostic relevance in marathon runners.

PURPOSE To prospectively analyze the myocardial distribution of late gadolinium enhancement (LGE) with delayed-enhancement cardiac magnetic resonance (MR) imaging, to compare the prevalence of this distribution in nonprofessional male marathon runners with that in asymptomatic control subjects, and to examine the prognostic role of LGE. MATERIALS AND METHODS Institutional review board and ethics committee approval were obtained for this study, and all subjects provided written informed consent. Two-dimensional inversion-recovery segmented k-space gradient-echo MR sequences were performed after administration of a gadolinium-containing contrast agent in 102 ostensibly healthy male runners aged 50-72 years who had completed at least five marathons during the past 3 years and in 102 age-matched control subjects. Predominantly subendocardial regions of LGE typical of myocardial infarction (hereafter, coronary artery disease [CAD] pattern) were distinguished from a predominantly midmyocardial patchy pattern of LGE (hereafter, non-CAD pattern). Marathon runners with LGE underwent repeat cardiac MR imaging and additional adenosine perfusion imaging. Runners were followed up for a mean of 21 months +/- 3 (standard deviation) after initial presentation. The chi(2), Fisher exact, and McNemar exact tests were used for comparisons. Event-free survival rates were estimated with the Kaplan-Meier method, and overall group differences were evaluated with log-rank statistics. RESULTS Of the 102 runners, five had a CAD pattern of LGE, and seven had a non-CAD pattern of LGE. The CAD pattern of LGE was located in the territory of the left anterior descending coronary artery more frequently than was the non-CAD pattern (P = .0027, Fisher exact test). The prevalence of LGE in runners was higher than that in age-matched control subjects (12% vs 4%; P = .077, McNemar exact test). The event-free survival rate was lower in runners with myocardial LGE than in those without myocardial LGE (P < .0001, log-rank test). CONCLUSION Ostensibly healthy marathon runners have an unexpectedly high rate of myocardial LGE, and this may have diagnostic and prognostic relevance.

Impact of papillary muscles in ventricular volume and ejection fraction assessment by cardiovascular magnetic resonance.

Cardiovascular magnetic resonance (CMR) is an accurate tool for the determination of right and left ventricular volumes and ejection fractions. However, the current standard short-axis technique is time-consuming and thus, often not practicable for routine daily use, because papillary muscles and trabeculations have to be marked and their volumes subtracted from the total ventricular volume. To reduce calculation time we evaluated the volumetric data that included papillary muscle and trabecular volumes and compared the outcome with the results of the standard technique. Thirty patients (17 healthy, 13 with coronary heart disease) were examined by CMR using TrueFISP (Magnetom, Siemens, Erlangen, Germany). Right and left ventricular volumes and ejection fractions were calculated using the standard short-axis technique and then again without subtracting papillary and trabecular volumes. The two methods were compared by determining the differences in results for ventricular volumes and ejection fractions. Statistically significant differences were found between the two methods for right and left ventricular stroke volumes and end-systolic volumes, and left ventricular end-diastolic volumes (EDV) (p < or = 0.011). No significant difference was found for right ventricular end-diastolic volumes (p > or = 0.149) or left or right ventricular ejection fraction (p > or = 0.130). Except in the case of left ventricular EDV, the deviations in the results of method 1 and method 2 did not vary significantly with the presence or absence of heart disease. Measurements were obtained considerably more quickly with the modified method than with the standard short-axis method (25 +/- 4 min vs. 13 +/- 3 min, p = 0.000). Although systematic differences were found when papillary and trabecular volumes were not subtracted, these differences are small and may not be of clinical relevance in healthy subjects or patients with coronary heart disease. Not subtracting the volumes of these structures enables faster determination of right and left ventricular volumes and ejection fractions without loss of the accuracy associated with the standard short-axis technique.

Rapid Detection of Myocardial Infarction by Subsecond, Free-Breathing Delayed Contrast-Enhancement Cardiovascular Magnetic Resonance

Background— An ultrafast, delayed contrast-enhancement cardiovascular magnetic resonance technique that can acquire subsecond, “snapshot” images during free breathing (subsecond) is becoming widely available. This technique provides myocardial infarction (MI) imaging with complete left ventricular coverage in <30 seconds. However, the accuracy of this technique is unknown. Methods and Results— We prospectively compared subsecond imaging with routine breath-hold delayed contrast-enhancement cardiovascular magnetic resonance (standard) in consecutive patients. Two cohorts with unambiguous standards of truth were prespecified: (1) patients with documented prior MI (n=135) and (2) patients without MI and with low likelihood of coronary disease (lowest Framingham risk category; n=103). Scans were scored masked to identity and clinical information. Sensitivity, specificity, and accuracy of subsecond imaging for MI diagnosis were 87%, 96%, and 91%, respectively. Compared with the standard technique (98%, 100%, 99%), the subsecond technique had modestly reduced sensitivity (P=0.0001), but specificity was excellent. Missed infarcts were generally small or subendocardial (87%). Overall, regional transmural extent of infarction scores were highly concordant (2083/2294; 91%); however, 51 of 337 regions (15%) considered predominantly infarcted (>50% transmural extent of infarction) by the standard technique were considered viable (≤25% transmural extent of infarction) by the subsecond technique. Quantitative analysis demonstrated moderately reduced contrast-to-noise ratios for subsecond imaging between infarct and remote myocardium (12.0±7.2 versus 20.1±6.6; P<0.0001) and infarct and left ventricular cavity (−2.5±2.7 versus 3.6±3.7; P<0.0001). Conclusions— MI can be rapidly detected by subsecond delayed contrast-enhancement cardiovascular magnetic resonance during free breathing with high accuracy. This technique could be considered the preferred approach in patients who are more acutely ill or unable to hold their breath. However, compared with standard imaging, sensitivity is mildly reduced, and the transmural extent of infarction may be underestimated.

Revival of an old method with new techniques: balloon aortic valvuloplasty of the calcified aortic stenosis in the elderly.

Balloon aortic valvuloplasty (BAV), introduced since almost 20 years, has experienced a revival for its use in the treatment of elderly patients with severe calcified aortic stenosis that are associated with high operative risk and co-morbidities. This is due to the introduction of new balloon catheters and techniques. This study reports about 75 such cases performed within the past 28 months. The mean age of our patient group was 78 ± 7 years (median = 80 years). Risk calculation with the EuroSCORE demonstrated an average value of 24.4 ± 19.5%. BAV was performed along with burst pacing to reduce transvalvular blood flow for stabilization of the balloon catheter until blood pressure dropped to less than 50 mmHg. BAV was performed in 72 patients with a procedural success rate of 73%. There was a decrease of 31 mmHg peak-to-peak gradient across the aortic valve from 63 ± 35 to 32 ± 22 mmHg (P < 0.0001). Mean gradient was reduced from 51 ± 24 to 27 ± 15 mmHg (P < 0.0001). Aortic valve area increased by 49% from 0.84 ± 0.33 to 1.25 ± 0.45 cm2 (P < 0.0001). Serious adverse events (SAE) occurred in 17% of the 75 BAV procedures. Follow-up revealed a significant improvement in 6-month and 1-year survival. The improved technology of BAV makes this technique attractive for elderly patients who are at high operative risk or in cases where valve replacement was refused for any reason.

Assessment of left atrial volumes in sinus rhythm and atrial fibrillation using the biplane area-length method and cardiovascular magnetic resonance imaging with TrueFISP.

OBJECTIVES To determine whether the biplane area-length method can be used for the evaluation of left atrial volumes and ejection fraction with cardiovascular magnetic resonance imaging (CMR) by TrueFISP in normal subjects and patients with atrial fibrillation. BACKGROUND Atrial fibrillation is the most common arrhythmia in elderly patients. Left atrial size and volumes play an important role in predicting short and long-term success after cardioversion. METHODS Fifteen healthy subjects (mean age 65.6+/-6.4 years) and 18 patients (mean age 67.2+/-8.8 years) with atrial fibrillation were examined by CMR (Magnetom, Siemens, Erlangen, Germany). Images were acquired by TrueFISP using the horizontal and vertical long-axis plane to measure left atrial end-diastolic and end-systolic areas and longitudinal dimensions. Volumes were determined with commercially available software. Left atrial end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) were determined by the biplane area-length method and compared to findings obtained by the standard short-axis method. Images were acquired and analyzed a second time in the patients with atrial fibrillation. RESULTS There was no difference in age between men and women (p=0.147) and healthy subjects and patients (p=0.128) included in the study. EDV and ESV were significantly higher and SV and EF significantly lower in patients with atrial fibrillation than in healthy subjects (p < or = 0.009), regardless of the method used. The values obtained for EDV and ESV by the biplane area-length method were significantly higher in both healthy subjects (p<0.001) and patients with atrial fibrillation (p<0.001) than those obtained by the standard short-axis approach, whereas SV (p> or = 0.057) and EF (p> or = 0.118) did not differ significantly. In the second investigation in patients with atrial fibrillation, ESV, SV, and EF did not differ significantly between the two methods (p> or =0.481). Assessment of interobserver variability revealed good agreement in the findings of the two observers, both in normal sinus rhythm and atrial fibrillation (overall variability 0.8+/-6.5%). CONCLUSIONS The biplane area-length method can be used in CMR images obtained by TrueFISP to assess left atrial volumes and ejection fraction in normal subjects and patients with varying cardiac cycle length, as in atrial fibrillation.

Right Ventricular Wall Motion Abnormalities Found in Healthy Subjects by Cardiovascular Magnetic Resonance Imaging and Characterized with a New Segmental Model

AIM To evaluate right ventricular wall motion abnormalities in healthy subjects using a new segmental model for the right ventricle. METHODS AND RESULTS 29 healthy subjects (9 female, 20 male, mean age 48.9+/-15 years) underwent cardiovascular magnetic resonance imaging (CMR; 1.5-Tesla Sonata, Siemens, Erlangen, Germany) for the evaluation of cardiac function and right ventricular wall motion. A steady-state free precession gradient-echo sequence (TrueFISP) was used. Right ventricular wall motion was analyzed, and the site of areas of disordered motion was classified according to the new segmental model. Such areas were seen in 27 (93.1%) of the 29 subjects. Dyskinesia was found in 22 subjects (75.9%), hypokinesia in 11 (37.9%), and bulging in 8 (27.6%). The number of wall motion abnormalities diagnosed was significantly higher in the transverse plane (86.2%) than in the short-axis plane (13.8%) and the horizontal longitudinal plane (41.4%; p = 0.000). CONCLUSION Right ventricular wall motion abnormalities are one of the criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy. However, our findings indicate that they may also be seen around the insertion of the moderator band in healthy subjects, so that the significance of their presence at this site in patients undergoing diagnostic investigations for this disease should be interpreted with caution.

Single and biplane TrueFISP cardiovascular magnetic resonance for rapid evaluation of left ventricular volumes and ejection fraction.

INTRODUCTION Cardiovascular magnetic resonance (CMR) allows very accurate, but time-consuming, volume assessment by the short-axis slice summation technique. The single and biplane methods of volume assessment are used less, partly because FLASH cine imaging provides poor blood-myocardium contrast in long-axis views. TrueFISP gives excellent blood-myocardium contrast, even in patients with heart failure. We hypothesized that the single plane and biplane methods of volume assessment in TrueFISP images might provide an acceptable degree of accuracy and be quicker than the short axis method, and that single and biplane left ventricular volume assessment would be more accurate with TrueFISP than with FLASH in patients with impaired ventricular function. METHODS Short- and long-axis CMR images were obtained by FLASH and TrueFISP with a 1.5-T scanner. We determined the accuracy of both single and biplane long-axis methods for left ventricular volume and ejection fraction (EF) measurements compared with the conventional short-axis method in 10 heart failure patients using both FLASH and TrueFISP and in 9 healthy subjects using TrueFISP. RESULTS No difference in volumes and EF was found between the single plane method, the biplane method, and the short-axis method using TrueFISP for image acquisition, in both patients and healthy subjects. The same was true of the results obtained by FLASH in the patients with heart failure. CONCLUSIONS The single and biplane methods, regardless of whether TrueFISP or FLASH is used, are a reasonable and rapid alternative to the conventional short-axis approach for left ventricular volume and EF assessment in patients with heart failure and impaired ventricular function.

Reference Right Atrial Function Determined by Steady-State Free Precession Cardiovascular Magnetic Resonance

BACKGROUND There is agreement that measurements of atrial volumes and ejection fraction (EF) are superior to atrial diameters for accurate determination of atrial size, follow up studies and prognosis. However, reference values for right atrial volumes and EF for cardiovascular magnetic resonance (CMR) have not been established but are crucial to identify patients with impaired right atrial function. METHODS AND RESULTS Atrial function was studied in 70 healthy subjects (52+/-16 years, 38 male) with both the standard short axis method (SA) and the area-length method (AL) using steady-state free precession gradient-echo cine imaging (SSFP). Intraobserver, interobserver (n=70) and interstudy (n=10) variability was assessed for both methods. Maximal volumes, minimal volumes and EF for SA and AL were 101.0+/-30.2 mL, 50.3+/-19 mL and 47.2+/-8.3%, and 103.2+/-32.6 mL, 50.8+/-20.2 mL and 51.4+/-9.2%, respectively. Maximal volumes, minimal volumes and EF were higher with AL than with SA (mean difference: 2.2+/-4.6 mL, 3.5+/-3.5 mL and 2.8+/-2.8%, respectively). Atrial function measurements were not related to gender (p>or=0.387) and age (rho<or=0.16) with either method. Intraobserver, interobserver and interstudy variability for volumes and EF was lower for SA compared to AL, with narrower limits of agreement. Analysis was faster with AL than with SA (62+/-18 s versus 7+/-2 minutes). CONCLUSION Normal ranges for right atrial function vary significantly between methods. AL is faster, but less reproducible than SA. Appropriate reference ranges should be used to differentiate normal from abnormal right atrial function.

Impact of the ECG gating method on ventricular volumes and ejection fractions assessed by cardiovascular magnetic resonance imaging

PURPOSE Most MRI centers currently use prospective ECG triggering and fast gradient-echo sequences for image acquisition. Retrospectively gated sequences allow the coverage of the entire cardiac cycle. There is concern about whether ventricular volumes and ejection fraction (EF) differ according to the gating method used for image acquisition. We sought to evaluate the impact of the gating method on measurements of right and left ventricular volumes and EF in normal subjects. MATERIALS AND METHODS Fifteen subjects with no cardiovascular disease were investigated by MRI using a 1.5 Tesla scanner. Images were acquired with a gradient-echo sequence with steady-state free precession (SSFP) using the standard short-axis method for volume and EF measurements. Images were acquired with 6-mn-thick slices using both prospective triggering and retrospective gating. Left and right ventricular volumes (EDV, ESV, SV) and EF were determined with a commercially available software package (Argus, Siemens). RESULTS EDV and SV calculated from short-axis images were significantly smaller with the prospectively triggered SSFP sequence (mean difference: EDV left: 13.9 +/- 4.4 mL, p < 0.0001; SV left: 13.5 +/- 4.8 mL, p < 0.0001; EDV right: 14.2 +/- 3.9 mL, p < 0.0001; SV right: 14.7 +/- 5.9 mL, p < 0.0001). EF was significantly smaller for the right ventricle (mean difference -3.6 +/- 3.3%, p = 0.0008) and the left ventricle (mean difference -2.3 +/- 3.3%, p = 0.02). ESV remained unchanged (mean difference: ESV left: 0.47 +/- 3.5 mL, p = 0.6179; right ESV: 0.5 +/- 3.7 mL, p = 0.6083). CONCLUSION The gating method has a significant impact on volume and EF measurements. The global ventricular EF is underestimated by using the prospective triggering technique. However, the difference in the left ventricle is small and might not be of clinical relevance.

Randomized comparison of effects of suture-based and collagen-based vascular closure devices on post-procedural leg perfusion

BackgroundVascular closure devices (VCD) are well established to facilitate hemostasis after cardiac catheterization procedures. However, impairment of flow due to the reduction of femoral artery diameter remains a major concern. The present study aims to evaluate leg perfusion before and after application of collagen- and suture-based vascular closure devices.MethodsA total of 366 patients (age: 64.3 years±10.7, male: 71.3%) were randomized to receive femoral access site closure with either a collagen-based closure device (group A) (n=214) or a suture-mediated device (group B) (n=152), immediately following coronary catheterization procedures. In all patients, the anklebrachial- index (ABI) was measured before and the day after closure device application.ResultsIn group A, mean ABI at baseline was 1.09±0.2, in group B 1.11±0.2. In both groups, there was a significant, albeit clinically not relevant, reduction in post-procedural ABI (group A: 1.04±0.2, p<0.01 vs baseline, group B: 1.06±0.2, p<0.01 vs baseline). ΔABI was not different between both VCD groups (p=0.55). In patients with peripheral vascular disease (PVD), neither the Angioseal device (mean ABI at baseline 0.76±0.1) nor the Perclose-device (mean ABI at baseline 0.79±0.1) induced a remarkable impairment of leg perfusion (Angioseal: 0.77±0.1, p=0.9 vs baseline, Perclose: 0.78±0.1, p=1.0 vs baseline). Clinically, no aggravation of claudication was observed in the PVD patient group.ConclusionBoth vascular closure devices are not associated with clinically relevant reduction in ABI. There was no difference between the two groups with respect to the level of flow impairment. Both devices may be safely used in patients with reduced ABI.