Ulrich Nellessen

Transesophageal two-dimensional echocardiography and color Doppler flow velocity mapping in the evaluation of cardiac valve prostheses.

To determine the value of transesophageal ultrasound in the assessment of cardiac valve prostheses, 14 patients with clinically suspected mitral prosthesis malfunction were studied by transthoracic and transesophageal two-dimensional imaging as well as by color Doppler flow velocity mapping (color Doppler). Patients underwent left ventricular angiography (n = 13), surgery (n = 11), or both angiography and surgery (n = 10). Nine patients had only mitral valve replacement, four patients had both mitral and aortic valve replacement, and one patient had mitral, aortic, and tricuspid valve replacement. There were 16 biological and four mechanical prostheses. The degree of mitral regurgitation was graded by both transthoracic and transesophageal color Doppler according to the area of the regurgitant jet visualized and was compared with a three-point classification of mitral regurgitation by left ventricular angiography judged by observers blinded to the echocardiographic results. All transesophageal studies were performed without complication and were well tolerated. The pathological morphology of the mitral prosthesis was additionally or more clearly visualized by transesophageal two-dimensional imaging and subsequently proven at surgery in three patients with flail leaflets and one patient with a vegetation compared with images obtained by the transthoracic approach. Valvular regurgitation was graded by the transthoracic approach as absent in four patients, mild in two patients, moderate in five patients, and severe in only three patients. The transesophageal assessment showed absence of mitral regurgitation in two patients, moderate regurgitation in two patients, and severe regurgitation in 10 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Impending paradoxical embolism from atrial thrombus: correct diagnosis by transesophageal echocardiography and prevention by surgery.

During recovery from a posterolateral myocardial infarction, a 56 year old patient developed signs of deep vein thrombophlebitis and subsequently of pulmonary embolism. After conventional echocardiography showed masses in both atria, transesophageal two-dimensional echocardiography clearly revealed an elongated mass overriding an atrial septal defect. Impending paradoxical embolism was confirmed at surgery.

Ultrasonic tissue characterization with a real time integrated backscatter imaging system in normal and aging human hearts

Experimental studies have shown that variation in the magnitude of integrated ultrasonic backscatter during the cardiac cycle represents acoustic properties of myocardium that are affected by pathologic processes; however, there are few clinical studies using integrated backscatter. Forty subjects without cardiovascular disease (aged 22 to 71 years, mean 41) were studied with use of a new M-mode format integrated backscatter imaging system to characterize the range of cyclic variation of integrated backscatter in normal subjects. Cyclic variation in integrated backscatter was noted in both the septum and the posterior wall in all subjects. The magnitude of the cyclic variation of integrated backscatter and the interval from the onset of the QRS wave of the electrocardiogram to the minimal integrated backscatter value were measured using an area of interest of variable size for integrated backscatter sampling and a software resident in the ultrasound scanner. The magnitude of cyclic variation was larger for the posterior wall than for the septum (6.3 +/- 0.8 versus 4.9 +/- 1.3 dB, p less than 0.01). The interval to the minimal integrated backscatter value was 328 +/- 58 ms for the septum and 348 +/- 42 ms for the posterior wall (p = NS). There was a weak correlation between the magnitude of cyclic variation of integrated backscatter and subject age for the posterior wall (r = -0.47, p less than 0.01), but this was not significant for the septum (r = -0.21) (partially because of inability to exclude specular septal echoes) and septal endocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Chronic aortic regurgitation: reassessment of the prognostic value of preoperative left ventricular end-systolic dimension and fractional shortening.

The prognostic significance of a preoperative echocardiographic left ventricular end-systolic dimension (ESD) greater than 55 mm and/or fractional shortening (FS) of 25% or less was evaluated retrospectively in 84 patients who had undergone aortic valve replacement for isolated chronic aortic regurgitation due to various causes. Postoperative survival, improvement in symptoms, and echocardiographic evidence of regression of left ventricular dilatation and hypertrophy were compared between patients with a preoperative ESD greater than 55 mm (category 1) and those with an ESD of 55 mm or less (category 2) and between patients with FS of 25% or less (category 3) and those with FS greater than 25% (category 4). Patients in categories 1 and 3 had a higher preoperative left ventricular end-diastolic dimension (EDD) and cross-sectional area than those in categories 2 and 4, respectively, but their preoperative functional impairment (NYHA class) was similar. There were 13 deaths, only two of which (one early, one late) could be attributed to left ventricular dysfunction. In both, FS was 25% or less and in one ESD was greater than 55 mm. There was a weak association without useful positive predictive value between the echocardiographic variables and postoperative death due to all causes. Among 42 patients with a preoperative ESD greater than 55 mm and/or FS of 25% or less, 33 (79%) were alive at a mean follow-up of 29.5 months. Symptoms improved in all categories of survivors, with the postoperative NYHA class being similar between categories 1 and 2 and between categories 3 and 4. Among 48 survivors with high-quality echocardiograms both before and after surgery, EDD fell in all groups but fell to a lesser extent in category 3 than in category 4. Postoperative cross-sectional area fell to the same level in all categories. Follow-up intervals were similar in all categories. We conclude that in patients undergoing aortic valve replacement for chronic aortic regurgitation, a preoperative ESD greater than 55 mm or an FS of 25% or less does not reliably predict early or late death, does not correlate with lack of improvement in symptoms, and does not preclude postoperative regression of left ventricular dilatation and hypertrophy. Thus these echocardiographic criteria alone cannot be used for the timing of surgical intervention in these patients.

Effects of acetylcholine on epicardial coronary arteries after cardiac transplantation without angiographic evidence of fixed graft narrowing

The coronary response to acetylcholine was evaluated in 10 patients who had had cardiac transplantation 1 to 8 years earlier and in 4 patients who did not undergo transplantation. All 14 patients had no angiographic evidence of fixed coronary arterial narrowing. Acetylcholine was infused in 10-fold increasing concentrations (10(-6) to 10(-2) M) into the midpoint of the left anterior descending coronary artery by an infusion catheter. Administration was terminated when either vasoconstriction was noted at fluoroscopy or when the maximal acetylcholine concentration was reached. Vascular responses were evaluated by quantitative angiography. All 14 patients had a decrease in coronary lumen size in response to acetylcholine. The mean percentage of vasoconstriction was 37 +/- 24% (p less than 0.001). Combined infusion of nifedipine and the maximal vasoconstricting dose of acetylcholine did not result in a significant reversal of coronary vasoconstriction in all 10 cardiac transplantation patients. It was concluded that acetylcholine is a potent coronary vasoconstrictor in patients who had cardiac transplantation and possibly lacks vasodilating effects in most normal patients without angiographic evidence of coronary artery disease, thus suggesting that acetylcholine might not be a suitable pharmacologic agent for testing endothelial cell integrity.

Effects of Radiation Therapy on Myocardial Cell Integrity and Pump Function: Which Role for Cardiac Biomarkers?

Background: Radiation therapy to the mediastinum and breast can be associated with cardiac complications. Cardiac damage may manifest early during radiation therapy or occur late, years after radiation therapy has been finished. Hypothesis: Myocardial damage is associated with the release of both troponin I (TnI) and brain natriuretic peptide (BNP). The current study sought to determine whether radiation treatment to the mediastinum and breast leads to the release of cardiac biomarkers. Methods: The study comprised 23 patients: 18 with lung cancer and 5 with breast cancer. Radiation therapy was performed for up to 6 weeks. Total radiation dose was >45 Gy in each patient with a dose of 1.8 Gy per fraction. Blood samples to determine TnI and BNP were taken before and once a week during radiation therapy. Echocardiography was done before and after radiation had been finished. Results: Two patients died during the study. Both TnI and BNP levels increased significantly during the study (log10 scale); however, absolute and mean values remained on a relatively low level (mean preradiation and postradiation TnI: 0.007 ± 0.008, 0.014 ± 0.01 ng/ml; mean preradiation and postradiation BNP: 123 ± 147, 159 ± 184 pg/ml). Conclusion: Radiation therapy leads to cardiac cell damage and changes in the left ventricular loading conditions as suggested by a significant increase of the cardiac biomarkers TnI and BNP. Determination of serum levels seems to be superior to echocardiography in detecting radiation-induced cardiac damage. Serial measurements of cardiac biomarkers may facilitate the management of patients undergoing radiation therapy and may help to define subgroups at high risk of developing heart failure.

Flow Velocity Acceleration in the Left Ventricle: A Useful Doppler Echocardiographic Sign of Hemodynamically Significant Mitral Regurgitation

Doppler echocardiography is a sensitive method to detect mitral regurgitation in patients with both native and prosthetic valves. However, estimates of the amount of mitral regurgitation remain semiquantitative, and even severe mitral regurgitation may be underestimated in the presence of markedly eccentric regurgitant jets or acoustic shadowing of the left atrium by mitral or aortic prostheses. This report describes the Doppler findings in 10 patients with severe native valve mitral regurgitation (angiographic grade III or IV) and in 15 patients with severe bioprosthetic mitral regurgitation that required valve replacement. An increase in peak mitral flow velocity above normal values was seen in eight of 10 patients with severe native valve mitral regurgitation (greater than or equal to 130 cm per second) and 11 of 15 patients with severe prosthetic valve mitral regurgitation (greater than or equal to 210 cm per second). One of 10 patients with a native valve and four of 15 patients with a bioprosthetic valve appeared to have only a localized left atrial systolic flow disturbance, incorrectly suggesting that the mitral regurgitation was mild. However, in all patients with severe mitral regurgitation, a low velocity (less than 100 cm per second) flow signal could be recorded in the left ventricle that was directed toward the mitral valve in systole. This flow signal showed a gradual increase in velocity as the sample volume was moved toward the mitral valve, with an abrupt further increase on entry into the left atrium. This signal was continuous with antegrade mitral flow and had the same orientation as mitral regurgitation recorded by continuous wave technique from the apex. A similar flow signal was not recorded in the left ventricle of any individual in a control group of 30 patients who had no mitral regurgitation or who had angiographic grade I or II mitral regurgitation. These findings suggest that acceleration of left ventricle flow toward the mitral valve in systole is only recorded when there is hemodynamically significant mitral regurgitation that is approximately equal to angiographic grade III or IV. Recognition of this Doppler finding may help in the estimation of mitral regurgitation severity, especially in difficult diagnostic situations.

Mitral prosthesis malfunction. Comparative Doppler echocardiographic studies of mitral prostheses before and after replacement.

To assess the influence of mitral prosthesis malfunction on various Doppler echocardiographic indexes, we studied the changes in the peak mitral flow velocity during early diastolic filling phase (Vmax), the mean transprosthesis pressure drop from the simplified Bernoulli equation, the mitral valve area by the pressure half-time method, and the left ventricular isovolumic relaxation time in 15 patients before and after replacement of the malfunctioning mitral prosthesis using continuous wave Doppler echocardiography. Examination of the 15 replaced prostheses revealed a torn or perforated leaflet in 12 valves and a sewing ring dehiscence in one valve. Additional restricted leaflet motion (classified as mild obstruction) was seen in three of these 13 valves. In the remaining two valves, severe prosthesis obstruction was noted. Changes in the Doppler indexes between the preoperative and postoperative study were present in all patients regarding Vmax (mean, 2.2 +/- 0.3 versus 1.6 +/- 0.2 m/sec; p less than 0.001), mean gradient (mean, 9 +/- 5 versus 5 +/- 0.8 mm Hg; p less than 0.001), and isovolumic relaxation time (mean, 47 +/- 12 msec versus 80 +/- 13 msec; p less than 0.001). The mean mitral valve area remained virtually unchanged (2.3 +/- 0.9 versus 2.6 +/- 0.3 cm2; p = NS) but increased postoperatively in each patient with preoperative mild or severe prosthesis obstruction without concomitant aortic regurgitation. Our conclusion is that the peak mitral flow velocity, the mean gradient, and the isovolumic relaxation time are useful parameters in the differentiation of normal and abnormal mitral prosthesis function but may not define the underlying lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Features of the angiographic evaluation of the INTACT study

SummaryINTACT (International Nifedipine Trial on Antiatherosclerotic Therapy) is a prospective, placebo-controlled, randomized, double-blind, multicenter trial analyzing the influence of 80 mg nifedipine/day on the angiographic progression of early stage coronary atherosclerosis. Coronary angiograms were taken in identical projections before and after a treatment period of 3 years. Quantitative analysis of the angiograms was performed with the computer-assisted contour detection system CAAS. For definition purposes, the coronary artery system was subdivided into 25 different segments, including all anatomic variants. Measurement parameters of segments were mean and minimal diameter, and of stenoses minimal diameter, percentage diameter reduction (at least 20%), length, and plaque area. The variable extent of the changes of these parameters in the different projections analyzed per patient in the two study angiograms was considered by separate computation of the maximal, mean, and minimal changes over these projections; the comparison of the parameter changes between the two treatment groups was performed separately according to these three modes.For all parameters, this comparison was performed on the basis of the individual 25 segments, as well as after aggregation of individual segments to arteries (RCA, LAD, and LCX), to groups of large and small segments, and to the entire coronary artery system.Assessment of changes of the coronary (patho)morphology by quantitative analysis of coronary angiograms is associated with a number of methodical limitations, which may lead to a certain variability of the results. However, due to the doubleblind feature of INTACT, this variability should be comparable in the two groups of this study, allowing for a conclusive comparison.

Improvement in Left Ventricular Diastolic Filling by Septal Myectomy in Hypertrophic Cardiomyopathy

Abnormalities in left ventricular diastolic function or filling are considered to be responsible for some of the symptoms in patients with hypertrophic cardiomyopathy. To clarify whether the abnormalities in left ventricular diastolic filling are improved by septal myectomy, 13 patients with hypertrophic cardiomyopathy and intracavitary pressure gradient were studied preoperatively and postoperatively by use of pulsed Doppler echocardiography. Peak early diastolic filling velocity (E), the ratio of peak early diastolic filling to peak atrial filling velocities (E/A ratio), and deceleration time were measured from the transmitral flow velocity pattern before and after septal myectomy. Although E and E/A ratio did not change after septal myectomy, deceleration time significantly shortened from 314 +/- 72 to 271 +/- 53 milliseconds (n = 10; p less than 0.05). Further, if seven patients with significant changes in heart rate (greater than 30%) or in the Doppler-determined severity of mitral regurgitation (more than one degree) were excluded (because these parameters may effect E and E/A ratio), there were also significant changes in E (81 +/- 21 versus 98 +/- 25 cm/sec, p less than 0.05) and in E/A ratio (0.84 +/- 0.17 versus 1.14 +/- 0.33, p less than 0.05). Because left ventricular systolic function has been demonstrated to remain constant or to decrease by most measures after septal myectomy, relief of some symptoms may be largely the result of the improvement in diastolic filling suggested by these criteria.