Myocardial perfusion by contrast echocardiography. Establishment of normal pattern of intracoronary injection and safety in humans

OBJECTIVE: To establish the normal pattern and safety of echocardiographic contrast in patients with no significant obstruction of epicardial coronary arteries. METHODS: 67 patients with normal coronary arteries or obstructions < 50% were selected from 277 patients who underwent coronary angiography (CA). Mean age was 56 ± 11years and 36 were males. At the end CA, echocardiographic contrast was selectively injected into each coronary artery. The parasternal short axis of the left ventricle (LV) was divided into six segments: anterior (A), antero-lateral (AL), postero-lateral (PL), posterior (P), infero-septal (IS) and antero-septal (AS). Anterolateral (ALPM) and posteromedial papillary muscles (PMPM) were also considered. The pattern and intensity of the appearance of the myocardial contrast was visually analyzed. RESULTS: The right coronary artery (RCA) was dominant in 60 patients. Contrast appearance was sudden and simultaneous in the 3 muscle layers. All segments could be contrasted after the injection in both coronary arteries. 100% of the AS, A and AL segments, 97% of the PL and 98% of the ALPM were perfused by the left coronary artery (LCA). P and IS segments were perfused by the RCA in 85% and 82%, respectively, and by a dominant LCA in 71% of the cases. The PMPM was perfused by a dominant RCA in 77% and by a dominant LCA in 86%. There were no symptoms. CONCLUSION: Intracoronary injection of the sonicated solution is a safe procedure that allows for an excellent opacification of the myocardium and can potentially be used during routine CA.

Study of Coronary Flow Reserve with Intravenous Use of Microbubbles (Contrast Echocardiography) and Adenosine: Protocol for Clinical Application in Patients Suspected of Having Coronary Heart Disease

OBJECTIVE: To test the feasibility, safety and accuracy of the adenosine protocol in the study of myocardial perfusion with microbubbles contrast echocardiography. METHODS: 81 pts (64 male, 60+11 years) were submitted to contrast echocardiography with PESDA (sonicated solution of albumin 20%-1ml, dextrose 5%-12ml and deca-fluorobutane gas-8ml) to study the myocardial perfusion at rest and after bolus injection of adenosine (6 to 18mg) and to coronary angiography within 1 month each other. For each patient 3 left ventricle perfusion beds were considered (total of 243 territories). 208 territories were analyzed and 35 territories were excluded. PESDA was continuously infused (1-2ml/min), titrated for best myocardial contrast. Triggered (1:1) second harmonic imaging was used. RESULTS: Coronary angiography showed 70 flow limiting (> 75%) lesions and 138 no flow limiting lesions. At rest an obvious myocardium contrast enhancement was seen in at least 1 segment of a territory in all patients. After adenosine injection an unquestionable further increase in myocardial contrast was observed in 136 territories (99%) related to no flow limiting lesions, lasting < 10 s, and a myocardial perfusion defect was detected in 68 territories (97%) related to flow limiting lesions. It was observed only 4 false results. There were no serious complications. CONCLUSION: Myocardial perfusion study with PESDA and adenosine protocol is a practical, safe and accurate method to analyze the coronary flow reserve.

Evaluation of stunned and infarcted canine myocardium by real time myocardial contrast echocardiography

Differentiation between stunned and infarcted myocardium in the setting of acute ischemia is challenging. Real time myocardial contrast echocardiography allows the simultaneous assessment of myocardial perfusion and function. In the present study we evaluated infarcted and stunned myocardium in an experimental model using real time myocardial contrast echocardiography. Sixteen dogs underwent 180 min of coronary occlusion followed by reperfusion (infarct model) and seven other dogs were submitted to 20 min of coronary occlusion followed by reperfusion (stunned model). Wall motion abnormality and perfusional myocardial defect areas were measured by planimetry. Risk and infarct areas were determined by tissue staining. In the infarct model, the wall motion abnormality area during coronary occlusion (5.52 ± 1.14 cm²) was larger than the perfusional myocardial defect area (3.71 ± 1.45 cm²; P < 0.001). Reperfusion resulted in maintenance of wall motion abnormality (5.45 ± 1.41 cm²; P = 0.43 versus occlusion) and reduction of perfusional myocardial defect (1.51 ± 1.29 cm²; P = 0.004 versus occlusion). Infarct size determined by contrast echocardiography correlated with tissue staining (r = 0.71; P = 0.002). In the stunned model, the wall motion abnormality area was 5.49 ± 0.68 cm² during occlusion and remained 5.1 ± 0.63 cm² after reperfusion (P = 0.07). Perfusional defect area was 2.43 ± 0.79 cm² during occlusion and was reduced to 0.2 ± 0.53 cm² after reperfusion (P = 0.04). 2,3,5-Triphenyl tetrazolium chloride staining confirmed the absence of necrotic myocardium in all dogs in the stunned model. Real time myocardial contrast echocardiography is a noninvasive technique capable of distinguishing between stunned and infarcted myocardium after acute ischemia.

Bioeffects of albumin-encapsulated microbubbles and real-time myocardial contrast echocardiography in an experimental canine model

Myocardial contrast echocardiography has been used for assessing myocardial perfusion. Some concerns regarding its safety still remain, mainly regarding the induction of microvascular alterations. We sought to determine the bioeffects of microbubbles and real-time myocardial contrast echocardiography (RTMCE) in a closed-chest canine model. Eighteen mongrel dogs were randomly assigned to two groups. Nine were submitted to continuous intravenous infusion of perfluorocarbon-exposed sonicated dextrose albumin (PESDA) plus continuous imaging using power pulse inversion RTMCE for 180 min, associated with manually deflagrated high-mechanical index impulses. The control group consisted of 3 dogs submitted to continuous imaging using RTMCE without PESDA, 3 dogs received PESDA alone, and 3 dogs were sham-operated. Hemodynamics and cardiac rhythm were monitored continuously. Histological analysis was performed on cardiac and pulmonary tissues. No hemodynamic changes or cardiac arrhythmias were observed in any group. Normal left ventricular ejection fraction and myocardial perfusion were maintained throughout the protocol. Frequency of mild and focal microhemorrhage areas in myocardial and pulmonary tissue was similar in PESDA plus RTMCE and control groups. The percentages of positive microscopical fields in the myocardium were 0.4 and 0.7% (P = NS) in the PESDA plus RTMCE and control groups, respectively, and in the lungs they were 2.1 and 1.1%, respectively (P = NS). In this canine model, myocardial perfusion imaging obtained with PESDA and RTMCE was safe, with no alteration in cardiac rhythm or left ventricular function. Mild and focal myocardial and pulmonary microhemorrhages were observed in both groups, and may be attributed to surgical tissue manipulation.

Clinical impact of transesophageal echocardiography in patients with stroke without clinical evidence of cardiovascular sources of emboli

OBJECTIVE: The purpose of this study is to evaluate the impact of transeophageal echocardiography on management of patients at low-risk for cardiogenic embolism to prevent new potential cardiovascular sources of emboli. METHODS: We studied 69 patients with ischemic stroke at low-risk for cardiogenic embolism. Transeophageal echocardiography was performed to access: left atrium enlargement; communication or aneurysm of the interatrial septum; patent foramen ovale; spontaneous echo contrast or intracavitary thrombi; the presence of intraaortic atherosclerotic plaques or thrombi; significant valvar morphologic alteration or dysfunction; left ventricle enlargement, hypertrophy, or contractile abnormality. Transesophageal echocardiography altered clinical management, and we adopted anticoagulant therapy or another procedure apart from the use of acetylsalicylic acid. RESULTS: Transeophageal echocardiography detected at least one abnormality in 40 cases (58%). Clinical conduct was adjusted after the performance of transesophageal echocardiography in 11 patients (15.9%); anticoagulation was added in 10 cases and surgical correction in one patient. CONCLUSION: Transeophageal echocardiography was a very useful tool in the secondary prevention for stroke in patients at low risk for cardiogenic embolism.

Use of transesophageal echocardiography during implantation of aortic endoprosthesis (stent). Initial experience

OBJECTIVE: To report the role played by transesophageal echocardiography during implantation of self-expanding aortic endoprostheses (stent) at a hemodynamics laboratory. METHODS: Thirteen patients underwent stent implantation in the descending thoracic aorta with the aid of transesophageal echocardiography during the entire procedure. Indications for stenting were as follows: 8 aortic dissections, 2 true aneurysms, 2 penetrating atherosclerotic ulcers, and 1 traumatic pseudoaneurysm. RESULTS: No complications resulting from the use of transesophageal echocardiography were observed. In 12 patients, the initial result was considered appropriate, with total or partial resolution of the major lesion confirmed by a posterior examination. In 1 patient, the procedure was suspended after transesophageal echocardiography and angiography showed that the proximal aortic diameter was inappropriate. Transesophageal echocardiography contributed to clarifying relevant points, such as aortic diameter, anatomic detail of the intimal lesion, and location and size of the communicating orifice. In addition, it facilitated placing the stent in the target lesion, reduced the time of exposure to radiation and the use of contrast medium, and provided rapid identification of intercurrent events, possibly reducing the total duration of the procedure. CONCLUSION: The use of transesophageal echocardiography during placement of aortic stents seems appropriate. The actual advantages of the procedure will be defined in a comparative prospective study.

Chagas disease: morbidity profile in an endemic area of Northeastern Brazil

Abstract: INTRODUCTION : This study evaluated the clinical forms and manifestation severities of Chagas disease among serologically reactive individuals from Western Rio Grande do Norte (Northeastern Brazil). METHODS : This cross-sectional study included 186 adults who were evaluated using electrocardiography, echocardiography, chest radiography, and contrast radiography of the esophagus and colon. A clinical-epidemiological questionnaire was also used. RESULTS : The indeterminate, cardiac, digestive, and cardiodigestive clinical forms of Chagas disease were diagnosed in 51.6% (96/186), 32.2% (60/186), 8.1% (15/186) and 8.1% (15/186) of the participants, respectively. Heart failure (functional classes I-IV) was detected in 7.5% (14/186) of the participants, and 36.4% (24/66), 30.3% (20/66), 15.2% (10/66), 13.6% (9/66), and 4.5% (3/66) of the patients were at stage A, B1, B2, C, and D, respectively. Dilated cardiomyopathy and electrocardiographic changes were detected in 10.2% (19/186) and 48.1% (91/186) of the participants, respectively. Apical aneurysm was diagnosed in 10.8% (20/186) of the participants, and other changes in the segmental myocardial contractility of the left ventricle were diagnosed in 33.9% (63/186) of the participants. Megaesophagus (groups I-IV) was observed in 7% (13/186) of the participants, megacolon (grades 1-3) was detected in12.9% (24/186) of the participants, and both organs were affected in 29.2% (7/24) of the megacolon cases. CONCLUSIONS : We detected various clinical forms of Chagas disease (including the digestive form). Our findings indicate that clinical symptoms alone may not be sufficient to exclude or confirm cardiac and/or digestive damage, and the number of patients with symptomatic clinical forms may be underestimated.

Color Doppler sonography with contrast in the differentiation of ovarian tumors

The objective of this study was to differentiate benign ovarian tumors from malignant ones before surgery using color and pulsed Doppler sonography, and to compare results obtained before and after use of contrast medium, thereby verifying whether contrast results in an improvement in the diagnostic sensitivity. METHODS: Sixty two women (mean age 49.9 years) with ovarian tumors were studied, 45 with benign and 17 with malignant tumors. All women underwent a transvaginal color Doppler ultrasonographic exam. A study of the arterial vascular flow was made in all tumor areas, as well as an impedance evaluation of arterial vascular flow using the resistance index. RESULT: Localization of the vessels in the tumor revealed a greater proportion of malignant tumors with detectable internal vascular flows (64%) than benign tumors with such flows (22%). There was a considerable overlap of these findings. The use of contrast identified a greater number of vessels with confirmation in the totality of tumors, but did not improve the Doppler capacity in tumoral differentiation. Malignant tumors presented lower values of resistance index than the benign ones, whether or not contrast was used. The cutoff value for resistance index that better maximized the Doppler sensitivity and specificity was 0.55. Through this value, an increase of the sensitivity after contrast use was obtained, varying from 47% to 82%, while specificity remained statistically unchanged. CONCLUSION: Although the injection of a microbubble agent improved the sensitivity of the method detecting vascularization of tumors, a positive finding for vascularization by this method was not clinically useful in the differentiation of benign and malignant ovarian tumors.

Percutaneous closure of atrial septal defects. The role of transesophageal echocardiography

PURPOSE: Evaluation of the role of transesophageal echocardiography in percutaneous closure of atrial septal defects (ASD) with the Amplatzer septal occluder. METHODS: Patients were selected for percutaneous closure of ASD by transesophageal echocardiography (TEE), which was also used to monitor the procedure, helping to select the appropriate size of the Amplatzer device, to verify its position, and to access the immediate results of the procedure. During the follow-up, TEE was used to evaluate the presence and magnitude of residual shunt (RS), device position, and right cardiac chamber diameters. RESULTS: Twenty-two (40%) of a total of 55 studied patients were selected. Thirteen underwent Amplatzer device implantation, eight are still waiting for it, and one preferred the conventional surgical treatment. All procedures were successful, which was mainly due to proper patient selection. Six (23%) patients acutely developed RS, which spontaneously disapeared at the three-month follow-up examination in three patients. There was a significant reduction in the right ventricle diastolic diameter, from 27mm (average) to 24mm and 20mm, one and three months after the procedure, respectively (p<0.0076). CONCLUSION: With the aid of TEE, percutaneous closure of ASD can be successfully, safely, and effectively performed.

Comparative study for the identification of myocardial ischemia by contrast ventriculography under the effect of isosorbide mononitrate and by perfusional myocardial scintigraphy in patients with ischemic heart disease

OBJECTIVE: To evaluate and compare the usefulness of cineventriculographies, before and after nitrate use, to technetium-99m sestamibi scintigraphy for the identification of myocardial ischemia. METHODS: Twenty-six patients were studied at basal conditions and 5 minutes after intravenous administration of isosorbide mononitrate (0.3mg/kg), to evaluate the performance and regional wall motion of the left ventricle (LV). The results were compared to those obtained with technetium-99m sestamibi scintigraphy. RESULTS: Before nitrate, contrast ventriculography identified 30 normal segments, 62 hypokinetic segments, 28 dyskinetic segments, and 14 akinetic segments. After drug administration, 99 segments were normal, 11 hypokinetic, 11 dyskinetic, and 13 akinetic. Myocardial scintigraphy revealed 110 ischemic segments and 18 fibrotic segments (p<0.005). After drug administration, the ventriculography showed increase in the velocity of circumferential fiber shortening (p=0.0142), the ejection fraction (p=0.0462), decrease in the end-systolic volume (p=0.0031) and no change in end-diastolic volume. CONCLUSION: Contrast ventriculography using nitrate proved to be similar to perfusional myocardial scintigraphy in the identification of myocardial ischemia.

Dynamic three-dimensional reconstruction of the heart by transesophageal echocardiography

OBJECTIVE: To evaluate echocardiography accuracy in performing and obtaining images for dynamical three-dimensional (3D) reconstruction. METHODS: Three-dimensional (3D) image reconstruction was obtained in 20 consecutive patients who underwent transesophageal echocardiography. A multiplanar 5 MHz transducer was used for 3D reconstruction. RESULTS: Twenty patients were studied consecutively. The following cardiac diseases were present: valvar prostheses-6 (2 mitral, 2 aortic and 2 mitral and aortic); mitral valve prolapse- 3; mitral and aortic disease - 2; aortic valve disease- 5; congenital heart disease- 3 (2 atrial septal defect- ASD - and 1 transposition of the great arteries -TGA); arteriovenous fistula- 1. In 7 patients, color Doppler was also obtained and used for 3D flow reconstruction. Twenty five cardiac structures were acquired and 60 reconstructions generated (28 of mitral valves, 14 of aortic valves, 4 of mitral prostheses, 7 of aortic prostheses and 7 of the ASD). Fifty five of 60 (91.6%) reconstructions were considered of good quality by 2 independent observers. The 11 reconstructed mitral valves/prostheses and the 2 reconstructed ASDs provided more anatomical information than two dimensional echocardiography (2DE) alone. CONCLUSION: 3D echocardiography using a transesophageal transducer is a feasible technique, which improves detection of anatomical details of cardiac structures, particularly of the mitral valve and atrial septum.

Structural and functional characteristics of rat hearts with and without myocardial infarct. Initial experience with doppler echocardiography

OBJECTIVE: To assess by Doppler echocardiography the structural and functional alterations of rat heart with surgical induced extensive myocardial infarction. METHODS: Five weeks after surgical ligature of the left coronary artery, 38 Wistar-EPM rats of both sexes, 10 of them with extensive infarction, undergone anatomical and functional evaluation by Doppler echocardiography and then euthanized for anatomopathological analysis. RESULTS: Echocardiography was 100% sensible and specific to anatomopathological confirmed extensive miocardial infarction. Extensive infarction lead to dilatation of left ventricle (diastolic diameter: 0.89cm vs.0.64cm; systolic: 0.72cm vs. 0.33cm) and left atrium (0.55cm vs. 0.33cm); thinning of left ventricular anterior wall (systolic: 0.14cm vs. 0.23cm, diastolic: 0.11cm vs. 0.14cm); increased mitral E/ A wave relation (6.45 vs. 1.95). Signals of increased end diastolic ventricle pressure, B point in mitral valve tracing in 62.5% and signs of pulmonary hypertension straightening of pulmonary valve (90%) and notching of pulmonary systolic flow (60%) were observed in animals with extensive infarction. CONCLUSION: Doppler echocardiography has a high sensitivity and specificity for detection of chronic extensive infarction. Extensive infarction caused dilatation of left cardiac chambers and showed in Doppler signals of increased end diastolic left ventricular pressure and pulmonary artery pressure.

Congestive heart failure. Correlation between functional class and systolic and diastolic functions assessed by Doppler echocardiography

OBJECTIVE: To evaluate the influence of systolic or diastolic dysfunction, or both on congestive heart failure functional class. METHODS: Thirty-six consecutive patients with a clinical diagnosis of congestive heart failure with sinus rhythm, who were seen between September and November of 1998 answered an adapted questionnaire about tolerance to physical activity for the determination of NYHA functional class. The patients were studied with transthoracic Doppler echocardiography. Two groups were compared: group 1 (19 patients in functional classes I and II) and group 2 (17 patients in functional classes III and IV). RESULTS: The average ejection fraction was significantly higher in group 1 (44.84%±8.04% vs. 32.59%±11.48% with p=0.0007). The mean ratio of the initial/final maximum diastolic filling velocity (E/A) of the left ventricle was significantly smaller in group 1 (1.07±0.72 vs. 1.98±1.49 with p=0.03). The average maximum systolic pulmonary venous velocity (S) was significantly higher in group 1 (53.53cm/s ± 12.02cm/s vs. 43.41cm/s ± 13.55cm/s with p=0.02). The mean ratio of maximum systolic/diastolic pulmonary venous velocity was significantly higher in group 1 (1.52±0.48 vs. 1.08±0.48 with p=0.01). A predominance of pseudo-normal and restrictive diastolic patterns existed in group 2 (58.83% in group 2 vs. 21.06% in group 1 with p=0.03). CONCLUSION: Both the systolic dysfunction index and the patterns of diastolic dysfunction evaluated by Doppler echocardiography worsened with the evolution of congestive heart failure.