Stress echocardiography: comparison of exercise, dipyridamole and dobutamine in detecting and predicting the extent of coronary artery disease.

OBJECTIVES: This study was designed to compare exercise, dipyridamole and dobutamine echocardiography in the same patients and to evaluate, by measuring physiologic and echocardiographic variables, the mechanisms by which exercise and dobutamine induce ischemia. BACKGROUND: The diagnostic value of stress echocardiography has been widely reported, but the specific effects of exercise, dipyridamole and dobutamine have not been directly compared. Furthermore, no echocardiography study has evaluated left ventricular volume changes at ischemic threshold during exercise and dobutamine administration. METHODS: One hundred patients with suspected (Group A, n = 60) or known (Group B, n = 40) coronary artery disease underwent all three tests in random order. RESULTS: In Group A, the sensitivities of exercise (mean 76%, 95% confidence interval [CI] 58% to 94%) and of dobutamine echocardiography (72%, 95% CI 53% to 91%) were higher than that of dipyridamole (52%, 95% CI 31% to 73%; p = 0.01 and p = 0.02, respectively). Specificity did not differ significantly among tests (94% for exercise [95% CI 86% to 100%] and 97% for dipyridamole and dobutamine [95% CI 91% to 100%]). Accuracy was identical for exercise and dobutamine (87%) and higher than that for dipyridamole (78%, p = 0.06). In Group B, the accuracy in predicting coronary disease extent was 71% for exercise, 33% for dipyridamole and 75% for dobutamine. At ischemic threshold, end-systolic volume index and the ratio of systolic blood pressure to end-systolic volume, a variable related to myocardial contractility, were significantly lower and higher, respectively, with dobutamine than during exercise (p < 0.05). CONCLUSIONS: In a clinical setting, exercise echocardiography should represent the first diagnostic approach because it has high diagnostic efficacy and provides additional information on exercise capacity; pharmacologic stress, particularly that of dobutamine, provides a pivotal diagnostic tool when exercise is not feasible or its results are nondiagnostic. Our preliminary data on echocardiographic evaluation at ischemic threshold support the view that myocardial contractility is a major factor in inducing ischemia during dobutamine infusion.

Transesophageal dipyridamole echocardiography for diagnosis of coronary artery disease.

The value of transthoracic dipyridamole echocardiography has been extensively documented. However, in some patients, because of a poor acoustic window, the rest transthoracic examination is not always feasible and the transesophageal approach is more convenient. Therefore, transesophageal echocardiography with high dose dipyridamole (up to 0.84 mg/kg body weight over 10 min) was performed in 32 patients in whom the transthoracic dipyridamole test either was not feasible (n = 29) or yielded ambiguous results (n = 3). The transesophageal echocardiographic test results were considered abnormal when new dipyridamole-induced regional wall motion abnormalities were observed. All 32 patients underwent coronary angiography; significant coronary artery disease was defined as greater than or equal to 70% lumen diameter narrowing in at least one major vessel. All patients also performed a bicycle exercise test 1 day before transesophageal dipyridamole echocardiography. Transesophageal stress studies were completed in all patients, with a maximal imaging time (in tests with a negative result) of 20 min. No side effects or intolerance to drug or transducer was observed. The left ventricle was always visualized in the four-chamber and transgastric short-axis views. High quality two-dimensional echocardiographic images were obtained in all patients both at rest and at peak dipyridamole infusion and were digitally analyzed in a quad-screen format. Coronary angiography showed coronary artery obstruction in 24 patients: 6 had single-, 9 double- and 9 triple-vessel disease. The transesophageal dipyridamole test showed a specificity of 100% and an overall sensitivity of 92%. The sensitivity of this test for single-, double- and triple-vessel disease was 67%, 100% and 100%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

IPO-V2: a prospective, multicenter, randomized, comparative clinical investigation of the effects of sulodexide in preventing cardiovascular accidents in the first year after acute myocardial infarction.

OBJECTIVES: This study was conducted to assess the efficacy of sulodexide, a glycosaminoglycan compound with antithrombotic properties, in preventing death and thromboembolic events after acute myocardial infarction. BACKGROUND: Antithrombotic therapy has been found to play an important role in the prevention of cardiovascular events and death after acute myocardial infarction. Glycosaminoglycan-containing compounds, including sulodexide, show profibrinolytic and antithrombotic properties that render them suitable for use in patients after infarction. METHODS: A total of 3,986 patients who had recovered from acute myocardial infarction were randomized to receive either the standard therapy routinely administered at each study center, excluding antiplatelet and anticoagulant drugs (control group, 1,970 patients), or the standard therapy plus sulodexide (treated group, 2,016 patients). Between 7 and 10 days after the episode of acute myocardial infarction, sulodexide was administered as a single daily 600-lipoprotein-lipase-releasing unit (LRU) intramuscular injection for the 1st month, followed by oral capsules of 500 LRU twice daily. Patients were evaluated for > or = 12 months. RESULTS: At the end of the study, 140 deaths (7.1%) were recorded in the control group and 97 (4.8%) in the sulodexide group (32% risk reduction, p = 0.0022, chi-square test). A total of 90 patients (4.6%) in the control group had a further infarction, compared with 66 (3.3%) in the sulodexide group (28% risk reduction, p = 0.035). Furthermore, a reduction in left ventricular thrombus formation (evaluated by echocardiography) was observed in the sulodexide group (n = 12; 0.6%), compared with values in the control group (n = 25; 1.3%) (53% risk reduction, p = 0.027). Sulodexide was well tolerated and devoid of significant adverse events. All significant results were confirmed by "actual treatment" analyses. CONCLUSIONS: The study provides evidence that long-term therapy with sulodexide started early after an episode of acute myocardial infarction is associated with reductions in total mortality, rate of reinfarction and mural thrombus formation.

Influence of residual perfusion within the infarct zone on the natural history of left ventricular dysfunction after acute myocardial infarction: a myocardial contrast echocardiographic study.

OBJECTIVES: This study used myocardial contrast echocardiography to investigate the extent of residual perfusion within the infarct zone in a select group of patients with recently reperfused myocardial infarction and evaluated its influence on the ultimate infarct size. BACKGROUND: Limited information is available on the status of myocardial perfusion within postischemic dysfunctional segments at predischarge and on its influence on late regional and global functional recovery. METHODS: Twenty patients with acute myocardial infarction were selected for the study. Patients met the following inclusion criteria: 1) single-vessel coronary artery disease; 2) patency of infarct-related artery with persistent postischemic dysfunctional segments at predischarge; 3) stable clinical condition up to 6 months after hospital discharge. All selected patients underwent coronary angiography and myocardial contrast echocardiography before hospital discharge and repeated the echocardiographic examination 6 months later. Patients were grouped according to the pattern of contrast enhancement in predischarge dysfunctional segments. RESULTS: In nine patients (group I), the length of segments showing abnormal contraction coincided with that of the contrast defect segments. In the remaining 11 patients (group II), postischemic dysfunctional segments were partly or completely reperfused. There was no difference between the two groups in asynergic segment length at predischarge (7.3 +/- 2.5 vs. 7.2 +/- 4.3 cm, p = NS). At follow-up study, asynergic segment length was significantly reduced in group II patients, whereas no changes were observed in group I patients (from 7.2 +/- 4.3 to 4.7 +/- 3.7 cm, p < 0.005; and from 7.3 +/- 2.5 to 7.5 +/- 2.9 cm, p = NS, respectively). CONCLUSIONS: Among patients with a predischarge patent infarct-related artery, further improvement in regional and global function may be expected during follow-up when residual perfusion in the infarct zone is present.

Tissue-type plasminogen activator therapy versus primary coronary angioplasty: impact on myocardial tissue perfusion and regional function 1 month after uncomplicated myocardial infarction.

OBJECTIVES: This study sought to compare the impact of primary coronary angioplasty and thrombolytic therapy for acute myocardial infarction (AMI) on 1-month infarct size and microvascular perfusion. BACKGROUND: The effect of the reperfusion strategies of primary coronary angioplasty and thrombolytic therapy on microvascular integrity still remains to be determined. METHODS: Sixty-two consecutive patients with a first AMI, undergoing intravenous tissue-type plasminogen activator (t-PA) therapy (32 patients, Group I) or primary angioplasty (30 patients, Group II), were studied. Only patients with 1-month Thrombolysis in Myocardial Infarction (TIMI) flow grade 2 or 3 were selected for the study. Patients in whom primary angioplasty was unsuccessful or those with clinical evidence of failed reperfusion were excluded. Microvascular perfusion was assessed at 1 month by intracoronary injection of sonicated microbubbles. Contrast score index (CSI) and wall motion score index (WMSI) were derived using qualitative methods. RESULTS: At baseline there were no significant differences between groups for age, risk factors, time to hospital presentation, Killip class on admission, prevalence of multivessel disease or anterior infarct site, infarct area extension before reperfusion, peak creatine kinase levels and postinfarction treatment. Conversely, significant differences between groups were found at follow-up for percent residual infarct related-artery (IRA) stenosis (70 +/- 12 vs 36 +/- 14 [mean +/- SD], p = 0.0001), CSI (1.02 +/- 0.4 vs. 1.49 +/- 0.5, p = 0.0003) and WMSI (1.67 +/- 0.3 vs. 1.45 +/- 0.3, p = 0.015). In particular, in the subset of patients with TIMI grade 3 flow, a perfusion defect occurred in one or more segments subtended by the IRA in 72% of Group I versus 31% of Group II patients (p < 0.00001) and in 27% of Group I versus 8% of Group II segments (p < 0.00001). CONCLUSIONS: The present study shows, in a highly selected cohort with successful IRA recanalization, that primary angioplasty is more effective than thrombolysis in preserving microvascular flow and preventing extension of myocardial damage at 1-month after AMI.

Clinical impact of echocardiography in prognostic stratification after acute myocardial infarction.

Risk stratification is mandatory in the management of the postinfarction period. The identification of high-risk patients, on the basis of clinical data (recurrent angina, overt heart failure, etc.), is quite easy, whereas stratification of uncomplicated subjects needs an accurate noninvasive strategy. In the last 20 years, echocardiography has been gaining an increasing role, allowing increasingly precise evaluation of infarct size. This detection of the extent of infarct size has a definite prognostic value. Since 1980, we have observed that a dysfunctioning left ventricular myocardium >40% marked patients with a poor prognosis. These observations are most important in asymptomatic infarct patients, in whom clinical features may not reflect the amount of left ventricular dysfunction. Our recent results on a large series of patients with acute myocardial infarction (MI) without overt heart failure have shown that the extension of wall motion abnormalities at 2-dimensional (2D) echocardiography was highly predictive of cardiac death or new coronary events in a 3-year follow-up (univariate analysis; p <0.0005). Echocardiography also plays an important role in detecting postinfarct ischemia, as seen by its wide use during stress tests. In our experience, the response to exercise echocardiographic testing has a high prognostic value. In fact, in our series, univariate analysis (Kaplan-Meier) showed that the best predictors of coronary events were the number of markers of ischemia during exercise (p <0.00001), the work load (p <0.00001), a positive exercise echo (p <0.0005), and the echo score at rest (p <0.0005). Multivariate analysis (Cox) confirmed these data: number of markers of ischemia: odds ratio (OR) 4.45, 95% confidence interval (CI) 1.5-13.1; work load: OR 2.46, CI 1.3-4.5; positive exercise echo OR 1.88, CI 1.1-3.2. Thus, serial echocardiography together with predischarge stress echocardiography is recommended for risk stratification after acute MI. In particular, in thrombolytic-treated patients, echo examinations allow the detection of functional recovery of viable reperfused myocardium whereas stress echo may show exercise-induced worsening in the region supplied by the infarct-related vessel, a predictor of a higher rate of coronary events.

Assessment of regional left ventricular function during exercise test with pulsed tissue Doppler imaging.

To investigate whether mitral annular velocity, measured by tissue Doppler imaging (TDI), is able to get a feasible quantitative evaluation of global and regional left-ventricular function during exercise test, 29 patients with previous uncomplicated myocardial infarction were studied by exercise echocardiography. All patients underwent coronary arteriography within 10 days of stress echocardiography. All of them were in sinus rhythm and had no right or left bundle branch block or significant mitral regurgitation as observed by left ventriculography. A total of 12 patients had anteroseptal and/or posteroseptal wall asynergies and left anterior descending involvement; 9 patients had lateral and/or posteroinferior asynergies and left circumflex coronary artery involvement; 8 patients had inferior and posteroseptal wall asynergies and right coronary artery involvement. Twelve subjects of same age and sex with normal cardiovascular findings were selected as a control group. TDI sample volumes were set on the mitral annuli corresponding to anteroseptal, posterior, posteroseptal, lateral, anterior, and inferior wall in 4-chamber, 2-chamber, and long-axis views. There was a significant correlation between the left-ventricular ejection fraction (0.41 +/- 0.8) and the means of the systolic (S) values (6.1 +/- 0.9 cm/sec, r = 0.83, p < 0.01). The mean S at the sites corresponding to the infarct regions (5.5 +/- 0.4 cm/sec) was significantly lower than the control group (11 +/- 0.8 cm/sec, p < 0.001). After stress, in patients with multivessel disease, S values corresponding to remote regions were significantly lower (p < 0.01) compared with control subjects. Thus, the parameters obtained from mitral annular velocities with pulsed TDI in patients with previous myocardial infarction reflect left ventricular asynergy corresponding to the infarct regions and reversible regional dysfunction after exercise.

Usefulness of echocardiography in the prognostic evaluation of non-Q-wave myocardial infarction.

Patients with non-Q-wave myocardial infarction (MI) are a heterogeneous population with a wide range of coronary disease severity and extent of myocardial necrosis, showing, therefore, different electrocardiographic findings and different outcomes. To evaluate the role of echocardiography in the management of non-Q-wave MI patients, 192 consecutive patients without previous MI were studied (78 with ST segment elevation, 56 with ST depression and 58 without ST modifications). All patients underwent 2-dimensional echocardiography (16-segment model) within 24 hours of admission to the coronary care unit. Wall-motion abnormalities, wall-motion score index, ejection fraction, and end-diastolic and end-systolic volumes were evaluated. In 35 patients, death, reinfarction, recurrent angina, or severe heart failure occurred during the in-hospital phase, whereas the remaining 157 patients had a good outcome. Patients with a poor prognosis were older (68 +/- 6 vs 59 +/- 5 years, p < 0.01), had a worse left-ventricular function (wall-motion score index 1.4 +/- 0.4 vs 1.25 +/- 0.3, p < 0.05; end-systolic volume 54 +/- 25 vs 38 +/- 12 mL/m2, p < 0.01; ejection fraction 50 +/- 10 vs 58 +/- 8%, p < 0.01), and presented more frequently with ST segment depression (49 vs 25%, p < 0.01). The positive and negative predictive values for early clinical events were, respectively: ST segment depression 0.30 and 0.87; wall-motion abnormalities in > 3 segments 0.28 and 0.86; wall-motion score index > 1.33 = 0.28 and 0.87; end-diastolic volume > 46 mL/m2 = 0.49 and 0.91; ST segment depression and wall-motion abnormalities in > 3 segments 0.60 and 0.88. These results underline the usefulness of echocardiography in the early risk stratification of non-Q-wave MI patients, together with electrocardiographic data. Patients with ST segment depression and more extensive wall-motion abnormalities are at higher risk and their management needs a more aggressive approach.

Influence of reperfusion induced by thrombolytic treatment on natural history of left ventricular regional wall motion abnormality in acute myocardial infarction.

Although several studies have investigated left ventricular (LV) function after reperfusion interventions, it is still unclear whether benefits result from successful therapy or whether such benefits only reflect the natural history of a subgroup of patients with acute myocardial infarction (AMI). This study evaluates the unique effect of thrombolytic therapy on the natural history of regional LV wall motion dysfunction. One hundred seventy-six patients with AMI were studied: 82 patients (group A) underwent conventional treatment and 94 (group B) thrombolytic therapy. LV regional improvement, evaluated by changes in echo score between admission and predischarge examination, was present more frequently in group B (28%) than in group A (17%). Furthermore, improved patients in group B had higher admission echo scores (7.5 +/- 3.5 vs 6.3 +/- 3.1), a prevalence of anterior AMI (68 vs 30.1%) and a higher rate of coronary patency (92 vs 58% in patients who had no improvement). In group A patients the rate of coronary patency was similar in those who did (46.1%) and did not have (36.1%) improvement. Observations at 12 to 18 months showed similar data in group A patients and in group B patients without improvement, whereas a marginal additional improvement was observed in group B patients who had in-hospital improvement. These observations demonstrate that LV function recovery is more frequent and marked in treated than in untreated patients. Follow-up results suggest a prolonged beneficial effect of thrombolytic treatment on LV function. The highest rate of coronary patency in improved group B patients underline the role of reperfusion on natural history of LV dysfunction after AMI.

Clinical application of exercise stress echocardiography: supine bicycle or treadmill?

Although exercise stress echocardiography is currently used to evaluate coronary artery disease (CAD) patients, the best exercise methodology is still undefined. The objectives of the study were: (1) to compare supine bicycle stress echocardiography (SBSE) and treadmill in the evaluation of CAD; and (2) to define, in normal subjects, the different behavior of factors determining MVO2 with treadmill and SBSE. We selected 10 male patients with CAD (group A), and 10 male control subjects (group B). Each patient underwent SBSE and treadmill testing in random order. We studied heart rate, systolic blood pressure, heart rate x systolic blood pressure, and end-diastolic and end-systolic volume indexes. In group A, we also studied wall motion score index (according to the American Society of Echocardiography) and in group B, systolic blood pressure/end-systolic volume index. The results were as follows: Group A: SBSE resulted in significantly lower work load, heart rate, and significantly higher systolic blood pressure, heart rate x systolic blood pressure, end-diastolic volume index, end-systolic volume index, and wall motion score index. SBSE showed wall motion abnormalities in each patient, whereas treadmill did not detect wall motion abnormalities in 4 patients (3 single-vessel; 1 multivessel); of the other 6 patients, 2 showed a lower wall motion score index and 4 did not show any difference in left ventricle kinetics with the 2 methodologies of exercise. Mean acquisition time for postexercise images was 72 +/- 6 seconds. Group B: SBSE resulted in lower work load, heart rate, heart rate x systolic blood pressure, systolic blood pressure/end-systolic volume index, and higher end-diastolic volume index and end-systolic volume index. Systolic blood pressure was similar with SBSE and treadmill testing. In conclusion, our experience suggests SBSE is a highly accurate diagnostic tool for evaluating CAD compared with treadmill testing; the maximum cardiovascular performance can be achieved with lower values of heart rate, suggesting the echo test is more feasible. Treadmill testing could lose important information about the existence, extension, and location of CAD; in contrast, SBSE detects even small, quickly reversible wall motion abnormalities.

Assessment of left ventricular dyssynergy by color kinesis.

Color kinesis is a new echocardiographic technique based on acoustic quantification. It has been developed to facilitate the ability to identify contraction abnormalities and has been incorporated into a commercially available ultrasound imaging system. The potential of this technique to improve the qualitative and quantitative assessment of wall motion abnormalities is described. Evaluation of color-encoded images allows detection of decreased amplitude of endocardial motion in abnormally contracting segments as well as a shorter time of endocardial excursion in segments with severely decreased motion. Compared with off-line quantitative studies, color kinesis has the advantage to be used on-line, without time-consuming manual tracing of endocardial boundaries. In addition, a single end-systolic color image contains the entire picture of spatial and temporal contraction and can be digitally stored and retrieved. In patients with proven coronary artery disease, color kinesis had a sensitivity of 88%, a specificity of 77%, and an overall accuracy of 86% in identifying the presence of segmental dysfunction. The practical application of color kinesis might be to improve our ability to distinguish normal from hypokinesis, something that has always been difficult in clinical echocardiography. Segmental analysis of color kinesis images allows objective detection of dobutamine-induced regional wall motion abnormalities in agreement with conventional visual interpretation of the corresponding 2-dimensional views. A method for objective assessment of wall dynamics during dobutamine stress echocardiography would be of particular clinical value, because these images are even more difficult to interpret than conventional echocardiograms. Quantitative assessment of diastolic function may allow objective evaluation of segmental relaxation abnormalities, especially under conditions of pharmacologic stress testing. Acquisition of color kinesis images during dobutamine stress echocardiography, both transthoracic and transesophageal, may facilitate the assessment of hybernating but viable myocardium and enhance the sensitivity in the detection of coronary artery disease.

Echocardiography in the coronary care unit: diagnostic and prognostic impact in comparison with clinical and other indicators.

The clinical arena in which we must consider the role of echocardiography is characterized by 2 fundamental findings: (1) most patients with chest pain and suspected acute myocardial infarction (MI) do not present diagnostic electrocardiograms; and (2) an early and correct diagnosis is necessary to match the patient with the most adequate treatment. Echocardiography may be very useful in the coronary care unit, allowing a correct diagnosis of ischemic heart disease when electrocardiography is unclear, even before the rise of cardiac enzymes is detected. It may also play a role in decision-making for thrombolytic therapy. In addition, echocardiography provides useful information for early risk stratification. In fact, although high-risk patients are well identified by simple clinical or instrumental variables (i.e., Killip classification, enzymatic data, blood-gas analysis, electrocardiogram, etc.), most patients (>60%) are identified as low risk, and several subjects classified into the low-risk groups have a poor prognosis and are not detected using a single variable. In our experience, 2-dimensional echocardiography was able to further stratify between patients of low-risk classes. Therefore, echocardiography plays an important role in the early stratification of acute MI patients, especially in those without signs or symptoms of heart failure.

The complex relation between myocardial viability and functional recovery in chronic left ventricular dysfunction.

Preserved myocardial viability and recurrent symptomatic ischemia are the most widely accepted criteria indicating that coronary revascularization should take place in patients with postischemic left ventricular dysfunction. However, the presence of viable myocardium within the infarct zone does not necessarily imply recovery of function after coronary revascularization. The complex relation between the extent of transmural necrosis and the degree of residual perfusion within the infarct area plays an important role. However, independently of functional recovery, cell viability may have important clinical implications, since it may improve long-term prognosis by attenuating left ventricular remodeling processes. Several different methods are used to detect hibernating myocardium. Mounting evidence suggests that thallium-201 scintigraphy is most sensitive in identifying tissue viability, whereas dobutamine echocardiography is most specific in predicting functional recovery after revascularization. In between, myocardial contrast echocardiography is the only technique able to evaluate the microvascular integrity that is a condition sine qua non for both cell viability and later functional recovery. Combined information derived from these 3 different approaches might be considered as the best way to understand how the combination of contractile, viable but noncontractile, and dead tissue affect resultant function and prognosis.

Value of transesophageal dobutamine stress echocardiography in assessing coronary artery disease.

The introduction of digital echocardiography has significantly enhanced our ability to select the best set of frames for analysis. However, despite the beneficial attributes of transthoracic dobutamine stress echocardiography, poor quality 2-dimensional images continue to be a significant limiting factor in patients with chest deformities, severe chronic obstructive lung disease, marked obesity, and previous chest surgery. Transesophageal echocardiography provides a new window to monitor left ventricular contractility without the interference of bone and air-filled structures of the thoracic cage. The transesophageal dobutamine stress test is a logical but poorly explored modality to image/stress the heart in certain patients with known or suspected myocardial ischemia. Overall sensitivity (< or = 85%) and specificity (< or = 95-100%) of transesophageal dobutamine stress echocardiography appear to be similar to that of previous transthoracic studies, although no direct comparison has been accomplished between transthoracic and transesophageal stress images. False negative transesophageal dobutamine stress echocardiography results have been described in patients with single-vessel disease in whom ischemic regions may not have been visualized throughout the entire study. False positive study results may be present in patients with hypertension and myocardial hypertrophy that may have signs and symptoms of myocardial ischemia in absence of obstructive disease of the epicardial coronary arteries, presumably related to either microvascular disease or impaired vasodilatory reserve. The proportion of patients with coronary artery disease who need a transesophageal examination for reliable assessment of echocardiographic response to stress varies depending on the operators' skills, the interpreters' experience, and the use of videotape or digitizing systems for image analysis. Although clinically useful in its present transthoracic and transesophageal form, a major limitation of dobutamine stress echocardiographic study is the subjective visual interpretation of endocardial motion and wall thickening, which is only semiquantitative. Color kinesis and tissue Doppler imaging (TDI) are 2 novel echocardiographic techniques that color code endocardial motion and myocardial velocity online and have the potential to objectively quantify regional left ventricular function. Quantitative standardization of transthoracic and transesophageal data interpretation, such as establishing endocardial motion by color kinesis or velocity thresholds by TDI for an abnormal segmental response to stress, has the potential to decrease interobserver variability and increase interinstitutional agreement.

Usefulness of the dipyridamole-Doppler test for diagnosis of coronary artery disease.

Two-dimensional and Doppler echocardiographic studies and a hemodynamic investigation were performed during dipyridamole testing in 42 subjects (13 control subjects and 29 patients with coronary artery disease [CAD]), to evaluate the ability of dipyridamole Doppler echocardiography in identifying patients with ischemic left ventricular dysfunction. In the control group, after dipyridamole infusion, Doppler-derived parameters increased significantly from baseline (p less than 0.001). In patients with CAD, peak flow velocity, flow velocity integral and stroke volume failed to increase after dipyridamole infusion (0.89 +/- 0.21 to 0.85 +/- 0.18 m/s, difference not significant; 14 +/- 3 to 12 +/- 4 cm, difference not significant, and 56 +/- 13 to 50 +/- 14 ml/beat, p less than 0.05, respectively). Heart rate, rate pressure product, systemic vascular resistance and mean right atrial pressure had similar variations in the 2 groups. Changes in the 3 Doppler-derived parameters are closely related to the variations of peak positive dP/dt, stroke volume (thermodilution) and left ventricular end-diastolic pressure and are closely related to the coronary angiography jeopardy score and to the appearance of wall motion abnormalities. Thus, by combining Doppler and 2-dimensional echocardiography, dipyridamole-induced myocardial ischemia may be detected in a high percentage of CAD patients, providing a sensitive tool for identifying patients with high-risk coronary artery anatomy.

Assessment of severity of coronary narrowings by quantitative exercise echocardiography and comparison with quantitative arteriography.

To determine the correlation of quantitative assessment of coronary narrowings with left ventricular functional impairment induced by exercise, 57 patients with 1-vessel coronary artery disease and without evidence of collateral flow were studied. A significant relation was observed between minimal cross-sectional area, percent area stenosis, minimal lumen diameter, percent diameter stenosis and the percentage of segmental area change from rest to peak exercise in a vascular distribution territory (r = 0.76, p less than 0.001; r = -0.55, p less than 0.001; r = 0.56, p less than 0.001; r = -0.75, p less than 0.001, respectively). For minimal cross-sectional area, the best cut-off value to separate significantly patients who had a decrease in contractility at peak exercise testing from those who had a normal response was 2 mm2 (p less than 0.001); for percent cross-sectional area stenosis, it was 75% (p less than 0.001); for minimal lumen diameter, it was 0.7 mm (p less than 0.001); and, for percent diameter stenosis, it was 85% (p less than 0.001). High cut-off values for angiographic variables are necessary to separate significantly patients who have a decrease in contractility at peak exercise testing from those who have a normal response. Several patients with mild coronary stenoses may have either normal or abnormal wall motion during exercise. Thus, exercise echocardiography is a useful tool in detecting the presence of fairly severe anatomic narrowing, whereas it is of limited clinical use in the assessment of intermediate coronary atherosclerotic lesions.

Usefulness of transesophageal echocardiography in the assessment of aortic dissection.

The acute dissection of the ascending aorta requires prompt and reliable diagnosis to reduce the high risk of mortality; in addition, prognosis is influenced by long-term complications. The aim of this article is to discuss transesophageal echocardiography (TEE) and (1) its diagnostic accuracy in the presurgical evaluation of patients, (2) its role in reducing time of diagnosis and surgery, and (3) its ability to reduce hospital mortality. TEE has also been tested as a screening method in the postsurgical follow-up of these patients. The retrospective investigation concerns a sample of 80 cases of acute dissection of the aorta, submitted for surgical intervention from April 1986 to February 1999. TEE has allowed a precise estimation of aortic diameters and optimal visualization of intimal flap and tear entry with a fine distinction between true and false lumen. A direct comparison of the results of TEE and of transthoracic echocardiography has demonstrated that some elements (visualization of flap and diameters in descending aorta, sites of entry and reentry, direction of jet trough intimal tears, phasic intimal flap movement, diastolic collapse of flap on the valvular plane, false lumen thrombosis, coronary involvement, intramural hematoma, and aortic fissuration) were identified only by TEE, whereas other additional diagnostic elements (cardiac tamponade, aortic valve insufficiency, left ventricular function) show a similar pattern of significance. Routine employment of this method has confirmed a reduction of hospitalization time (about 1.5 hours of waiting time), and hospital mortality has changed from 42.8% to 17.3%. In the follow-up of patients operated on for aortic dissection, fundamental information may be obtained from TEE (assessment of the progression of thrombosis in the false lumen with its complete obliteration and modifications in aortic diameter with a consequent, possible worsening of aortic valve insufficiency). In conclusion, our study demonstrated that TEE may provide fast and efficient detection of acute aortic dissection. In the postsurgical follow-up, TEE has confirmed detection of major complications that can influence long-term prognosis and may be proposed as a method with easy access-one that is repeatable and inexpensive for the screening of aortic dissection surgical patients.

Effectiveness of thrombolysis is associated with a time-dependent increase of malondialdehyde in peripheral blood of patients with acute myocardial infarction.

By using a highly sensitive, high-performance liquid chromatographic technique, plasma values of malondialdehyde (MDA), adenosine and oxypurines were determined in 10 healthy subjects, 10 patients with noncardiac illness, and 20 patients with acute myocardial infarction (AMI) observed within 6 hours from the onset of symptoms. Patients with AMI received fibrinolytic treatment. Peripheral blood was obtained before and serially after thrombolysis (1, 2, 3, 6 and 24 hours). Coronary patency was assessed by timing of peak creatine phosphate kinase and by predischarge angiography. MDA (mean +/- SD) in healthy subjects, noncardiac patients, and immediately before thrombolytic treatment in patients with AMI was 0.051 +/- 0.013, 0.066 +/- 0.020 and 0.397 +/- 0.326 mumol/liter of plasma, respectively. A progressive increase in plasma MDA after thrombolysis was observed only in reperfused patients, whose values at the third, sixth and 24th hours were also significantly greater than those of nonreperfused patients. Time-dependent variations of xanthine and adenosine were also observed in the same group after thrombolysis. The data appear to indicate that a relevant increase in plasma MDA, mostly originating due to phospholipid derangement of postischemic myocytes, occurs only in patients with successful thrombolysis, thus suggesting that if properly assayed, it may represent reliable biochemical evidence of tissue injuries after myocardial reperfusion in humans.

Assessment of diastolic left ventricular filling by echocardiographic automated border detection and comparison with radionuclide ventriculography.

To determine whether indexes obtained from a newly developed echocardiographic automated border detection (ABD) technology provide a reliable estimate of left ventricular (LV) diastolic filling, ABD variables of LV filling were compared with volumetric measurements determined by radionuclide angiography. Forty-two patients with a variety of heart diseases (age range, 11 to 76 years) underwent ABD echocardiographic studies on the same day as the radionuclide examination. Technically adequate ABD data could be obtained in 31 patients (74%). Nineteen healthy subjects served as normal controls. Area-time and volume-time waveforms for echocardiographic measurements were obtained from LV short-axis views at the level of the papillary muscles and four-chamber apical views. Both the diastolic indexes derived from the waveform of area change (short-axis view) and volume change (four-chamber apical view) correlated with radionuclide variables. Values measured from the ABD area-time waveform showed the following correlations: peak filling rate (r = 0.86; standard error of the estimate [SEE] = 0.62), time to peak filling rate (r = 0.85; SEE = 23.11), rapid filling phase fractional change (r = 0.79; SEE = 5.51), and atrial filling phase fractional change (r = 0.71; SEE = 5.82). Correlations of indexes derived from the ABD volume-time waveform were as follows: peak filling rate (r = 0.87; SEE = 0.50), time to peak filling rate (r = 0.90; SEE = 22.03), rapid filling fractional change (r = 0.83; SEE = 5.33), and atrial filling fractional change (r = 0.77; SEE = 4.68). ABD LV filling parameters in patients with heart disease and normal control subjects were significantly different. Thus ABD data from short-axis and apical views have a strong linear relation with radionuclide ventriculographic measurements and may be used as a method to assess LV diastolic filling.

On-line quantitative assessment of left ventricular filling during dobutamine stress echocardiography: a useful addition to conventional wall motion scoring.

In order to determine whether the diastolic rate of ventricular volume change obtained on-line with an automatic border detection (ABD) system during dobutamine stress echocardiography (DSE) would provide an interpretation of the diastolic ventricular response to the drug in quantitative terms in the assessment of coronary artery disease, we studied, with ABD and DSE, 59 patients who underwent coronary arteriography within 2 months of the stress test. Eleven patients had normal coronary findings or non-significant coronary lesions. Significant (> or =70% diameter stenosis) coronary artery disease (CAD) was present in 48 patients (81%). Dobutamine stress echocardiography (DSE) to a maximal dose of 50 microg/kg per min was performed in all patients. ABD images were acquired at rest and at the peak of infusion along with conventional two-dimensional images. The following measurements were evaluated: left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), slope of rapid filling segment (RFS), peak filling rate (PFR), rapid filling phase fractional change (RFFC). Patients with non-significant coronary artery lesions exhibited a hyperdynamic response with an LVEF increment of at least 20% from baseline to peak drug infusion. In these patients the effect of dobutamine produced an increase of RFS from 35.5+/-5.6 to 86.5+/-10.5 ml/s, an increase of PFR from 4.4+/-0.6 to 6.8+/-0.6 EDV/s, and an increase of RFFC from 74+/-8 to 92+/-5% (P<0.001). Of the 48 patients with coronary artery disease, 27 had <20% LVEF increase at peak dobutamine infusion. Four of 22 patients with single vessel disease and 23 of 26 patients with multivessel disease had an abnormal systolic response. After dobutamine infusion single vessel CAD patients showed a decrease of RFS from 33.4+/-5.3 to 26.7+/-5.9 ml/s, a decrease of PFR from 3.8+/-0.7 to 3.0+/-0.7 EDV/s, and a decrease of RFFC from 73+/-6 to 59+/-4% (P<0.001). Multivessel CAD patients showed a decrease of RFS from 32.0+/-5.9 to 23.1+/-4.1 ml/s, a decrease of PFR form 3.8+/-0.6 to 2.8+/-0.6 EDV/s, and a decrease of RFFC from 71+/-5 to 54+/-8% (P<0.001). The overall sensitivity of detecting CAD was 85% for conventional DSE and 90% for ABD-DSE (P=NS). The sensitivities of detecting patients with single vessel and multivessel CAD with conventional DSE were 68 and 92%, respectively, and with ABD-DSE were 91% (P<0.01) and 96% (P=NS), respectively. Our results show that an abnormal diastolic as well as systolic response during on-line quantitative assessment of dobutamine stress echocardiography is a sensitive marker of coronary artery disease and is predictive for the detection of extensive lesions. The described measurements can be utilized to improve the DSE sensitivity in identifying coronary artery disease. On-line quantitation of diastolic indexes with ABD can represent another step toward obtaining uniform results after stress echocardiography.