Effect of intravenous contrast for left ventricular opacification and border definition on sensitivity and specificity of dobutamine stress echocardiography compared with coronary angiography in technically difficult patients.

BACKGROUND: The study evaluates whether Optison used during dobutamine stress echocardiography (DSE) will improve endocardial border definition and whether this will translate to an improvement in sensitivity and specificity of the test in patients with poor echocardiographic windows. DSE is extremely valuable in the workup of patients with coronary artery disease. The test is limited in patients with suboptimal endocardial border visualization. Frequent studies have demonstrated improved endocardial border visualization with intravenous contrast agents at rest. METHODS AND RESULTS: We studied 229 patients: 112 had good rest echocardiography with no contrast and 117 had poor rest echocardiography with Optison injection during DSE. Percentage of endocardial border visualization, wall thickening, sensitivity, and specificity were compared in both groups, as was interobserver variability. Both groups were matched with respect to age, percentage of previous myocardial infarctions, resting wall motion abnormality, percentage of coronary stenosis, and number of diseased coronary arteries. Optison significantly improved endocardial border visualization, especially at peak stress. The ability to measure wall thickening was significantly higher in the contrast DSE group with suboptimal images versus the noncontrast group with optimal images (89% ability to measure wall thickening vs 71%, P =.01). This resulted in a comparable sensitivity (79% vs 71%, P = not significant [NS]), specificity (76% vs 82%, P = NS), and diagnostic accuracy (80% vs 76%, P = NS). Agreement on test interpretation was higher among 3 observers in contrast DSE versus noncontrast DSE groups (79% vs 69%, P =.01). CONCLUSIONS: In patients with poor echocardiographic windows, the use of Optison during DSE improves endocardial border visualization, which translates to a comparable sensitivity and specificity to noncontrast DSE tests in patients with good echocardiographic windows.

Evolving role of echocardiography in the management of atrial fibrillation.

The most common cardiovascular arrhythmia is atrial fibrillation (AF), with an estimated prevalence of 2.5 million in 1994. The extent of this public health problem is enormous, particularly in its stroke sequelae. Routine management of this public health problem includes anticoagulation as the primary stroke-preventive measure. Echocardiography has been an important adjunctive tool in the evaluation of AF. More innovative and controversial is the putative role of transesophageal echocardiography in the treatment strategy of AF cardioversion to sinus rhythm. The standard of care for AF of less than 1-year duration is to attempt cardioversion to sinus rhythm. An alternative strategy is to utilize the assets of transesophageal echocardiography to visually screen the left atrium for thrombus, thereby playing an active role in the treatment strategy of AF. This review will discuss the role of echocardiography in AF as it was initially used as a diagnostic tool with weak prognostic features, and, more recently, as it can be used today as an adjunctive tool to guide therapy with excellent stroke risk-stratification features.

For left ventricular opacification and endocardial border definition: is it really important which contrast agent we use, or is it the imaging modality we choose?

AIMS: The purpose of this study was to prospectively compare the effect of three imaging modalities (fundamental, harmonics, and power harmonics) on left ventricular opacification and endocardial border definition with two different echo agents, Optison and Albunex. METHODS: A total of 84 patients who had suboptimal transthoracic images were studied with echo contrast agents Albunex (n=41) and Optison (n=43). Each contrast agent was examined with three different imaging modalities, fundamental, harmonics and power harmonics, respectively. Left ventricular opacification was obtained by videodensitometric analysis. Percentage of endocardial border visualization was determined by indexing circumference of visualized endocardium to total circumference. Variables were compared with respect to three imaging modalities between two different echo agents. RESULTS: Higher videointensities and higher percentages of endocardial visualization were achieved with Optison compared to Albunex with fundamental and harmonics. However, there was no significant difference between Optison and Albunex with respect to LV opacification and border visualization by power harmonics. CONCLUSION: These results indicate that left ventricular opacification and endocardial border visualization is significantly improved by using power harmonic imaging as compared to harmonics or fundamental imaging following both echo contrast agents. Furthermore, although Optison is clearly superior to Albunex in opacifying left ventricle, power harmonic imaging compensates for the less robust agent.

Transesophageal echocardiography and unexplained cerebral ischemia: a multicenter follow-up study. The STEPS Investigators. Significance of Transesophageal Echocardiography in the Prevention of Recurrent Stroke.

BACKGROUND: Transesophageal echocardiography (TEE) continues to play a prominent role in the evaluation of patients with unexplained cerebral ischemia. The STEPS Study Group (Significance of Transesophageal Echocardiography in the Prevention of Recurrent Stroke) was established to further examine the clinical significance of TEE findings in patients with suspected cardiac source of embolus and to assess the impact of these findings with respect to specific therapy and the prevention of recurrent events. METHODS: A total of 242 patients from 15 institutions within the United States underwent TEE study for evaluation of unexplained cerebral ischemia. Over a 1-year period, detailed follow-up was obtained with respect to recurrent stroke, transient ischemia attacks, or documented embolic events as well as detailed information concerning nonrandomized antithrombotic therapy. RESULTS: Recurrent stroke occurred in 17 of 132 (13%) of the patients in the aspirin group versus 5 of 110 (5%) of the patients receiving warfarin therapy (P <.02). This decrease in cerebral ischemic events in the warfarin group was noted, despite the higher prevalence of atrial fibrillation and impaired ventricular function in the warfarin group. The selection of antithrombotic therapy appears, at least in part, to have been influenced by the TEE findings. Among patients receiving aspirin, a higher recurrent stroke rate was noted in those with left ventricular enlargement and atherosclerotic aortic plaque. CONCLUSION: Abnormalities are commonly found by TEE in patients with unexplained cerebral ischemia. Patients with left ventricular enlargement and demonstrable aortic plaque on TEE study are at increased risk for recurrent stroke when receiving aspirin therapy alone. Empiric therapy with systemic anticoagulation may be indicated in patients with stroke unexplained by carotid atherosclerotic disease.

Mitral valve replacement: randomized trial of St. Jude and Medtronic Hall prostheses.

BACKGROUND: This study was designed to better define the merits of the bileaflet and tilting-disc valves. METHODS: We prospectively randomized 156 patients (mean age, 59 years) to receive either the St. Jude (n = 80) or the Medtronic Hall (n = 76) mitral valve prosthesis between September 1986 and December 1997. The two groups were not significantly different with respect to preoperative New York Heart Association class, left ventricular ejection fraction, incidence of mitral stenosis or insufficiency, extent of coronary artery disease, completeness of revascularization, or cross-clamp or bypass time. RESULTS: The operative mortality (11.2% versus 13.1%, St. Jude versus Medtronic Hall, respectively) and late mortality (27% versus 22%, St. Jude versus Medtronic Hall, respectively) were not significantly different. Follow-up was complete in all hospital survivors with a mean of 60.7 months (range, 1 to 133 months). The analysis of 10-year actuarial survival and freedom from valve-related events demonstrated no significant differences between the cohorts. Freedom from reoperation was higher in the St. Jude group (p < 0.01). Comparisons of patient functional status and echocardiographic hemodynamic parameters obtained at the time of follow-up demonstrated no significant differences between the two prostheses. CONCLUSIONS: This study suggests that there is no difference between the St. Jude and Medtronic Hall prostheses with respect to late clinical performance or hemodynamic results and therefore does not support the preferential selection of either prosthesis.

Prognostic significance of late-peaking left ventricular velocity contour in patients with aortic stenosis undergoing valve replacement.

BACKGROUND: The presence of an abnormal late-peaking left ventricular velocity contour, detected by Doppler echocardiography, has been reported in patients with hypertrophic cardiomyopathy, left ventricular hypertrophy, and aortic stenosis. METHODS AND RESULTS: To evaluate the clinical and prognostic significance of this characteristic Doppler finding, we studied a group of patients (n = 57) with isolated AS undergoing aortic valve replacement. Patients were divided into two groups according to the presence (n = 28) or absence (n = 29) of a hypertrophic late-peaking left ventricular velocity pattern. There were no differences between the groups with respect to age, sex, and presence of coronary artery disease. Peak preoperative aortic valve gradients were similar in both groups (70 vs. 67 mm Hg; p = not significant). The postoperative course of patients with abnormal late-peaking ventricular velocity contour was complicated by a higher incidence of arrhythmias (80% vs. 38%; p = 0.0002). Hypotension and the use of inotropic support were significantly more common in the group with abnormal late-peaking ventricular velocity contour (79% vs. 24%; p = 0.0001 and 76% vs. 26%; p = 0.0001, respectively). Hemodynamically, patients with a late-peaking velocity pattern exhibited a higher pulmonary diastolic pressure (16+/-3 vs 12+/-2 mm Hg; p = 0.0003), wedge pressure (12+/-4 vs 10+/-2; p < 0.05), and systemic vascular resistance (2126+/-459 vs 1553+/-199; p = 0.0001) and lower cardiac index (2.4+/-0.3 vs 2.9+/-0.4; p = 0.0001). CONCLUSIONS: An abnormal late-peaking ventricular velocity contour pattern appears to be a high risk marker for postoperative complications in patients undergoing aortic valve replacement. Routine Doppler evaluation in patients undergoing valve replacement for AS may therefore identify these patients.

Increasing the dose and rate of Albunex infusion leads to superior left ventricular contrast effect.

In routine clinical use, the efficacy of Albunex in producing clinically useful opacification may be lower than in initial clinical studies. We hypothesized that increasing either the rate of injection or amount of Albunex administered would increase left ventricular opacification. Fifty adult volunteers were each injected with Albunex in five volume/rate combinations. Blinded reviewers evaluated left ventricular opacification and endocardial border delineation compared with the baseline (noncontrast) echocardiogram. In addition, captured digitized images were analyzed with video-densitometric techniques. Injected at the highest volume/rate tested (20 ml at 3.0 ml/sec), Albunex provided the greatest improvement in left ventricular opacification, endocardial border delineation, and quality of the echocardiogram. The administration of Albunex caused no serious adverse events at any volume/rate regimen tested. Our data indicate that faster injection rates and larger dose volumes than those currently recommended by the package insert significantly improve Albunex ultrasound contrast without compromising safety.

Effect of treatment of isolated systolic hypertension on left ventricular mass.

CONTEXT: Left ventricular (LV) hypertrophy is a common problem among elderly patients with isolated systolic hypertension (ISH), but the effect of treatment of ISH on LV mass is not known. OBJECTIVE: To assess the ability of antihypertensive drug treatment to reduce LV mass in ISH. DESIGN: Echocardiographic Substudy of the Systolic Hypertension in the Elderly Program (SHEP). PATIENTS: A total of 104 participants at the St Louis SHEP site who had interpretable baseline echocardiograms, 94 of whom had 3-year follow-up echocardiograms. INTERVENTION: The SHEP participants were randomized to placebo or active treatment with chlorthalidone (12.5-25 mg/d), with atenolol (25-50 mg/d) added if necessary to maintain goal blood pressure. MAIN OUTCOME MEASURE: Change in LV mass assessed by echocardiography. RESULTS: Minimum follow-up was 3 years. In the active treatment group, 91% and 80% of subjects were receiving treatment with chlorthalidone alone by the end of years 1 and 3, respectively. The LV mass index was 93 g/m2 in the active treatment group and 100 g/m2 in the placebo group (P<.001). The LV mass index declined by 13% (95% confidence interval, - 3% to - 23%) in the active treatment group compared with a 6% increase (95% confidence interval, - 3% to + 16%) in the placebo group over 3 years (P=.01). CONCLUSION: Treatment of ISH with a diuretic-based regimen reduces LV mass.

Mobile aortic atheroma and systemic emboli: efficacy of anticoagulation and influence of plaque morphology on recurrent stroke.

OBJECTIVES: We sought to determine the influence of plaque morphology and warfarin anticoagulation on the risk of recurrent emboli in patients with mobile aortic atheroma. BACKGROUND: An epidemiologic link between aortic atheroma and systemic emboli has been described both in pathologic and transesophageal studies. Likewise, a few studies have found an increased incidence of recurrent emboli in these patients. The therapeutic implications of these findings has not been studied. METHODS: Thirty-one patients presenting with a systemic embolic event and found to have mobile aortic atheroma were studied. The height, width and area of both immobile and mobile portions of atheroma were quantitated. The dimensions of the mobile component was used to define three groups: small, intermediate and large mobile atheroma. The patients were followed up by means of telephone interview and clinical records, with emphasis on anticoagulant use and recurrent embolic or vascular events. RESULTS: Patients not receiving warfarin had a higher incidence of vascular events (45% vs. 5%, p = 0.006). Stroke occurred in 27% of these patients and in none of those treated with warfarin. The annual incidence of stroke in patients not taking warfarin was 0.32. Myocardial infarction occurred in 18% of patients also in this group. Taken together, the risk of myocardial infarction or stroke was significantly increased in this group (p = 0.001). Forty-seven percent of patients with small, mobile atheroma did not receive warfarin. Recurrent stroke occurred in 38% of these patients, representing an annual incidence of 0.61. There were no strokes in patients with small, mobile atheroma treated with warfarin (p = 0.04). Likewise, none of the patients with intermediate or large mobile atheroma had a stroke during follow-up. Only three of these patients had not been taking warfarin. CONCLUSIONS: Patients presenting with systemic emboli and found to have mobile aortic atheroma on transesophageal echocardiography have a high incidence of recurrent vascular events. Warfarin is efficacious in preventing stroke in this population. The dimension of the mobile component of atheroma should not be used to determine the need for anticoagulation.

Valve replacement in the small aortic annulus: prospective randomized trial of St. Jude with Medtronic Hall.

OBJECTIVE: The ideal prosthesis for aortic valve replacement in patients with small annuli remains controversial and has yet to be identified. The purpose of this report is to compare the St. Jude (SJ) Medical and Medtronic Hall (MH) valves for aortic valve replacement in the small aortic root. METHODS: From 1986 to 1994 we prospectively randomized 456 patients to receive either the SJ or the MH valve. From this population, 80 patients (SJ, 42 patients; MH 38 patients) had a 19 or 21 mm aortic prosthesis inserted without annulus enlarging procedure. RESULTS: Follow-up was complete in all 80 patients for 270 patient years (mean 40.5 months). Analysis showed that the SJ and MH groups were similar with respect to age, gender, body surface area, valve area, NYHA class, ventricular function, prosthesis size, frequency of revascularization, bypass and global ischemic time. There were two operative deaths (1 SJ, 1 MH). Clinical performance and Dobutamine stress transesophageal doppler echocardiography could not demonstrate a significant advantage of one prosthesis over the other in this population. The change in aortic valve gradient, and left ventricular mass index measured preoperatively and within 12 months postoperatively were not different in both cohorts. CONCLUSION: The study could not detect a difference in the performance of the SJ and MH heart valves for aortic valve replacement in patients with small aortic annuli.

Pharmacologic stress-induced regional myocardial blood flow heterogeneity and left ventricular wall thickening abnormality: comparison of intravenous adenosine with dipyridamole in a model of critical coronary stenosis.

Variations in reported sensitivity of myocardial perfusion scans or wall motion abnormalities during pharmacologic stress with intravenous adenosine and dipyridamole may be caused by differences in myocardial oxygen demand or myocardial blood flow redistribution induced by each agent. To investigate the physiologic correlates of functional abnormalities during pharmacologic stress testing, regional myocardial blood flow (radiolabeled microsphere technique) and left ventricular segmental wall thickening (quantitative two-dimensional echocardiography) were measured in 9 dogs with an open chest model of critical stenosis of the left circumflex coronary artery. Data were obtained at baseline and peak drug infusion for intravenous adenosine (0.42 mg/kg over a 3-minute period) and for intravenous dipyridamole (0.56 mg/kg over a 4-minute period). Adenosine and dipyridamole induced regional flow abnormality in 7 (77%) of 9 dogs. Myocardial segments with decreased endocardial/epicardial flow ratio were similar for both agents (2.9 +/- 1.8 vs 2.7 +/- 1.3, p = [NS]). Segments with myocardial flow heterogeneity (ratio of endocardial flow to control left anterior descending/left circumflex endocardial flow) were similar for both agents (2.7 +/- 0.9 vs 2.3 +/- 1.0, p = NS). Adenosine-induced wall thickening abnormality (77% vs 55% with dipyridamole) correlated with regional flow abnormality. Significantly lower mean arterial pressure (53 +/- 1.7 mm Hg vs 64 +/- 1.9 mm Hg, p < 0.01) and more prolonged drug effect (18 +/- 6.4 min vs 3 +/- 1.4 min, p < 0.001) were seen for dipyridamole compared with adenosine. Adenosine induces regional flow abnormality similar to dipyridamole but with less hemodynamic perturbation, and adenosine-induced wall thickening abnormality more closely parallels regional flow abnormality.

Myocardial toxoplasmosis complicating cardiac transplant.

The increase in numbers of immunocompromised patients has been reflected by an increasing frequency of opportunistic infections. Of these, Toxoplasma gondii has been reported as a significant human pathogen following cardiac transplantation. In this setting, quiescent toxoplasma myocardial cysts may become active after implantation into a therapeutically immunosuppressed host. The consequences of infection are significant and carry a high morbidity and mortality. We present the clinical and pathologic characteristics of a patient with toxoplasma infection complicating cardiac transplant and review previously reported cases of this entity.

Relation between pulmonary venous flow and pulmonary wedge pressure: influence of cardiac output.

Multiple factors affect the systolic and diastolic components of pulmonary venous flow. It has been suggested that left ventricular function might influence the effects of filling pressures on indexes of pulmonary venous flow. The present study was designed to evaluate the effect of the pulmonary wedge pressures, left ventricular function, and cardiac output on the pulmonary vein flow pattern. Forty-five patients undergoing cardiac surgery were included in this study. Pulmonary venous flow and mitral flow variables were obtained by transesophageal echocardiography with hemodynamic variables obtained simultaneously. In the total group, there was no consistent relation between the pulmonary venous flow or the mitral flow parameters and the capillary wedge pressures. When patients were grouped according to normal (> 2.2 L/min/m2) or low (< 2.2 L/min/m2) cardiac index, a significant and positive relation was found between the systolic component of the pulmonary venous flow and the pulmonary wedge pressure in patients with normal cardiac index (r = 0.69; p = 0.003). Conversely, in patients with low cardiac index there was also a significant although negative correlation between the systolic velocity integral and the pulmonary wedge pressure (r = -0.58; p < 0.001). In conclusion, the systolic component of the pulmonary venous flow correlates closely and significantly with the capillary wedge pressures. The direction of this relation depends to a large extent on the total cardiac output and to a lesser extent on the left ventricular systolic function as assessed by the ejection fraction.

Differential characterization of blood flow, velocity, and vascular resistance between proximal and distal normal epicardial human coronary arteries: analysis by intracoronary Doppler spectral flow velocity.

To characterize coronary blood flow velocity parameters and to determine the relation among velocity, volumetric flow, and vascular resistance in awake human beings, we performed paired proximal and distal velocity measurements in 28 angiographically normal coronary arteries. Mean velocity, peak velocity, diastolic-to-systolic velocity ratio, and diameter and cross-sectional area of proximal and distal arteries were determined and coronary flow and vascular resistance computed. Mean velocity and coronary vasodilator reserve were similar for all three native arteries and were preserved from proximal to distal segments. Volumetric flow decreased from proximal to distal segments. The demonstrated inverse and curvilinear (polynomial) relation between volumetric flow and vascular resistance agrees with theoretical and animal models of coronary physiologic characteristics and suggests a nadir of coronary vascular resistance below which coronary flow no longer increases.

Quantitation of aortic regurgitation by Doppler echocardiography: a practical approach.

Aortic regurgitation is most frequently assessed noninvasively by Doppler echocardiography by use of continuous wave and Doppler color flow mapping. To compare both Doppler methods, 161 patients who had undergone cardiac catheterization and complete echocardiographic studies were studied. The continuous wave parameters analyzed included the slope of the diastolic deceleration and the pressure half-time of the regurgitant jet. From color flow Doppler, conventional parameters such as JH and its ratio to LVOH, JASA and its ratio to LVOA, and the regurgitant JA and its ratio to the LVA were obtained. The JH/LVOH was the color flow parameter that best correlated with angiography (r = 0.91). A ratio of < or = 25% was used to predict mild aortic regurgitation with 96% accuracy. A ratio of > or = 40% was also used to predict severe aortic regurgitation (3 to 4+) with 96% accuracy. Absolute JH at the origin of the regurgitant jet was the second best color flow parameter that correlated with angiography (r = 0.89). When continuous wave-derived slope was used, a significant overlap among different degrees of aortic regurgitation was observed. Predictive accuracy for mild aortic regurgitation was 70% by using a slope < 2 m/sec2 and 86% for severe aortic regurgitation when using a slope > 3 m/sec2. In conclusion, color flow Doppler appears to be superior to continuous wave Doppler in the assessment of aortic regurgitation. The JH/LVOH appears to be the best color parameter for quantifying aortic regurgitation. The measurement of the absolute JH at its origin appears to be the simplest and most practical method for assessing the degree of aortic regurgitation.

Hemodynamic significance of coronary jet velocity in patients: limitations of the Bernouilli equation in small conduits.

The objective of this study was to assess the use of coronary stenosis velocity in the determination of translesional pressure gradients. In the physiologic assessment of coronary stenosis, the accelerated intracoronary flow velocity within a narrowing has correlated with minimal lesion cross-sectional area according to the continuity equation. In large conduits the jet velocity can determine pressure gradients when used in the Bernouilli equation. However, the use of intralesional flow velocity for calculation of translesional pressure gradients by the simplified Bernouilli equation (delta P = 4V2) may be inaccurate in small (< 5 mm diameter) conduits. Translesional pressure (2.2F catheter) and flow velocity (0.018-inch guidewire) were measured in a single coronary artery in 23 patients undergoing diagnostic angiography or angioplasty. The electronically determined mean of phasic proximal and distal pressure and planimetry of the instantaneous phasic pressure gradient were used and compared with the instantaneous velocity calculations of pressure by the simplified Bernouilli formula with both maximal jet velocity and a modified formula including proximal velocity. The mean measured translesional pressure gradient was 18 +/- 13 mm Hg (range 0 to 50 mm Hg) and was equivalent to the instantaneous average pressure gradient by planimetry. The maximal jet velocity was 125 +/- 40 cm/sec (range 63 to 250 cm/sec), yielding a calculated pressure gradient of 3 +/- 3 mm Hg. The calculated pressure gradient by the simplified Bernouilli equation correlated poorly with the measured translesional gradient (r = 0.27, F = 1.63, p = 0.21).(ABSTRACT TRUNCATED AT 250 WORDS)

Prosthetic valves for the small aortic root.

Mechanical aortic valves (AVs) are frequently implanted in small (19 and 21 mm) aortic roots because bioprosthetic valves have unacceptably high gradients and many surgeons do not implant allograft valves. Three mechanical valves in common use today in the United States are the Starr-Edwards (SE), St. Jude Medical (SJ), and the Medtronic-Hall (MH). Clinical hemodynamic studies reveal that the 21-mm SE valve (size 8A) has peak systolic gradients of 13 to 58 mmHg (N = 6) with a calculated effective orifice of 0.7 to 1.4 cm2. The 19-mm SJ valve has a gradient at peak pressure of 17 mmHg and a mean gradient of 22 mmHg (N = 6) with respective exercise gradients of 32 and 38 mmHg (N = 5). For the 21-mm SJ valve the mean gradient was 5.2 +/- 5.3 (N +/- 12) and the gradient at peak pressure was 6.0 mmHg (N = 15). The 21-mm MH valve had resting gradients at peak pressure of 10.5 (N = 3) and 12.4 mmHg (N = 9) and exercise gradients of 15.8 mmHg (N = 9). Six months after AV replacement with small SJ or MH (N = 14) or large (23 mm or greater) (N = 83) valves, cardiac output was 4.7 versus 6.4 L/min (p < 0.03), percent reduction in left ventricular mass index (LVMI) was -8% versus -21% (p < 0.01), exercise duration was 370 versus 555 seconds, and congestive heart failure (CHF) class was 1.9 versus 1.1 (p < 0.0001). Change in LVMI and valve size were the only independent predictors of CHF class.(ABSTRACT TRUNCATED AT 250 WORDS)