Diana Rinkevich

Measurement of myocardial blood flow velocity reserve with myocardial contrast echocardiography in patients with suspected coronary artery disease: comparison with quantitative gated technetium 99m sestamibi single photon emission computed tomography

BACKGROUND The ability of high and low mechanical index (MI) imaging methods during myocardial contrast echocardiography (MCE) to assess the physiologic significance of coronary stenoses were compared with technetium 99m sestamibi single photon emission computed tomography (SPECT) in patients. METHODS Intermittent ultraharmonic imaging (high MI) and power modulation angio (low MI) were performed during continuous infusions of the echo-enhancing contrast agent, Optison, at rest and after dipyridamole stress in 39 patients. Technetium 99m sestamibi SPECT was performed simultaneously. Images from the 3 apical windows were divided into 6 walls. Myocardial blood flow (MBF) velocity and MBF velocity reserve were quantified from pulsing interval versus acoustic intensity MCE curves in each wall using postprocessed images. RESULTS Approximately 25% of the myocardial walls could not be analyzed from MCE because of artifacts. MBF velocity and MBF derived from both MCE methods increased significantly after dipyridamole in healthy patients (n = 143 and 129 walls for high and low MI, respectively), compared with those with either reversible (n = 11 and 10 walls for high and low MI, respectively) or fixed defects (n = 18 and 14 walls for high and low MI, respectively) on SPECT. Consequently, MBF velocity and MBF reserve were significantly greater for patients with normal perfusion. Receiver operator characteristic curves obtained for MBF velocity reserve provided a sensitivity and specificity of 82% and 87%, respectively, for high MI; versus 64% and 96%, respectively, for low MI imaging after uninterpretable images were excluded from analysis. CONCLUSIONS Both high and low MI MCE imaging techniques can be used to determine the presence of perfusion defects as identified by technetium 99m sestamibi SPECT. Low MI imaging methods have a number of drawbacks that limit its sensitivity compared with high MI techniques.

Prognostic Value of Dipyridamole Stress Myocardial Contrast Echocardiography: Comparison With Single Photon Emission Computed Tomography

BACKGROUND Dipyridamole stress myocardial contrast echocardiography (MCE) can be used to detect coronary artery disease (CAD). Because it measures myocardial blood flow velocity in addition to measuring myocardial blood volume, it was hypothesized that it should have greater prognostic utility than single photon-emission computed tomography (SPECT), which measures only myocardial blood volume. Because blood flow mismatch precedes wall thickening (WT) abnormalities during demand ischemia, it was also postulated that perfusion on MCE would be superior to WT abnormalities on echocardiography for this purpose. METHODS The incidence of nonfatal myocardial infarction and cardiac death was determined in 261 patients with known or suspected CAD over a mean follow-up period of 14 months who underwent simultaneous dipyridamole stress MCE and 99mTc-sestamibi SPECT. Comparisons of survival curves were conducted with stratified (and unstratified) log-rank tests. RESULTS Abnormal results on MCE were found to be the best predictor of an adverse outcome (odds ratio, 23; 95% confidence interval, 6-201; P<.0001) and provided incremental prognostic value over clinical variables (age>60 years, the presence of >or=3 cardiac risk factors, known peripheral vascular disease, prior myocardial infarction, and left ventricular systolic function), inducible WT abnormalities, and SPECT. Prognoses were worst in patients who had both abnormal results on MCE and inducible WT abnormalities and best in those who had neither. Patients with abnormal results on MCE but no inducible WT abnormalities had intermediate outcomes. CONCLUSION In patients with known or suspected CAD undergoing dipyridamole stress, MCE provides powerful prognostic information that is superior to clinical variables, electrocardiography, left ventricular systolic function, WT analysis, and SPECT. MCE may therefore serve as a method of choice for myocardial perfusion assessment in patients with known or suspected CAD. Larger studies are needed to confirm these findings.

Septal/Free Wall Curvature Ratio: A Noninvasive Index of Pulmonary Arterial Pressure

The leftward septal shift, a well-recognized feature of pulmonary hypertension, was used to quantify right ventricular pressure in 16 patients with pulmonary hypertension and 11 control patients, all with normal left ventricular function. Pulmonary pressure was calculated from the tricuspid regurgitation jet and left ventricular pressure was taken by arm cuff measurements. Short-axis echocardiographic images were obtained and the midwall curvatures of the septum and the left ventricular free wall were measured for each frame from end diastole to end systole and averaged. The septal/free-wall curvature ratio (CR) was 0.37 +/- 0.19 in the study group compared with 0.79 +/- 0.06 in the control group (p < 0.0001). A tight relationship between the CR and the transseptal/transmural pressure ratio (CR = 0.057 + 0.89 x transseptal/transmural pressure ratio; r = 0.98; p < 0.001) was obtained by linear regression. Given the systolic arterial pressure, the pulmonary systolic pressure is given by: systolic arterial pressure x (1.064-1.12 x CR). Therefore the CR can be used as a noninvasive index that reflects the level of pulmonary pressure in relationship to the systolic arterial pressure.

Long-term follow-up of patients with severe rheumatic tricuspid stenosis

BACKGROUND Tricuspid stenosis is a part of the chronically rheumatic heart. Although rare, when tricuspid stenosis does occur, it occurs in the setting of coexistent mitral and aortic valve disease. The natural course of patients with severe tricuspid stenosis is not well defined. The aim of this study is to present close follow-up of patients with chronic rheumatic heart disease and severe tricuspid stenosis. METHODS AND RESULTS We retrospectively studied 13 patients (11 women and 2 men) with severe tricuspid stenosis who were followed closely for 6 to 31 years. The mean tricuspid pressure gradient ranged from 3 to 9 mm Hg. Twelve patients underwent surgery for mitral and/or aortic valve lesions without complications. Concomitant tricuspid valve surgery was performed on six patients: two De Vega procedures, two Kay plications, and two implantations of Carpentier rings. All these also had leaflet commissurotomy. After surgery, the mean tricuspid gradient decreased in three patients, did not change in two, and increased in one. All 13 patients were treated with diuretics, digoxin, warfarin, and spirinolactone or ACE inhibitors. On their last follow-up visit, every patient had increased jugular venous pressure. Hepatomegaly was found in 6 of 13, leg edema in 4 of 13, and ascites in 1 of 13. CONCLUSIONS Most tricuspid stenos patients are women with severe mitral and aortic valve disease. After successful repair of the mitral or aortic valve, and regardless of the type of tricuspid valve surgery, severe tricuspid stenosis was found to be very well tolerated by all the patients over many years of follow-up.

Missed diagnosis of severe symptomatic aortic stenosis.

Patients with angina pectoris and congestive heart failure with a systolic murmur should be suspected of having significant AS. These patients are frequently women with atrial fibrillation and no left ventricular hypertrophy criteria on the electrocardiogram. Echocardiography with calculation of the aortic valve area is indicated in all these patients.

Cost-Efficiency of Myocardial Contrast Echocardiography in Patients Presenting to the Emergency Department With Chest Pain of Suspected Cardiac Origin and a Nondiagnostic Electrocardiogram

Assessment of patients presenting to the emergency department (ED) with suspected cardiac chest pain and a nondiagnostic electrocardiogram (ECG) is lengthy and costly. It was hypothesized that myocardial contrast echocardiography (MCE) can be cost-efficient in such patients by detecting those with chest pain that is noncardiac in nature. Accordingly, cost-efficiency was evaluated in 957 patients presenting to the ED with suspected cardiac chest pain, but no ST-segment elevation on the ECG, who underwent MCE. Economic outcome calculations were based on costs estimated from national average Medicare charges adjusted by a cost-charge ratio. Based on routine clinical criteria, 641 patients (67%) were admitted to the hospital, whereas 316 (33%) were discharged directly from the ED. The average cost per patient using routine evaluation was

Coronary Autoregulation Is Abnormal in Syndrome X: Insights Using Myocardial Contrast Echocardiography

5,000. Patients with normal MCE results (n = 523) had a very low primary event rate (death, acute myocardial infarction) of 0.6% within 24 hours after presentation, making it relatively safe to discharge patients directly from the ED with a normal MCE result. Hence, if MCE had been used for decision making, 523 patients (55%) would have been discharged directly from the ED and 434 (45%) would have been admitted to the hospital. Preventing unnecessary admissions and tests would have saved an average of

Digital Subtraction Myocardial Contrast Echocardiography: Design and Application of a New Analysis Program for Myocardial Perfusion Imaging

900 per patient, in addition to reducing their ED stay. In conclusion, by excluding cardiac causes in patients presenting to the ED with chest pain and a nondiagnostic ECG, MCE can prevent unnecessary admissions and downstream resource utilization, making it a cost-efficient tool in the evaluation of these patients.

Consensus development and application of ICD-9-CM codes for defining chronic illnesses and their complications

BACKGROUND Syndrome X in women is thought to be caused by coronary microvascular dysfunction, the exact site of which is unknown. The aim of this study was to characterize the microvascular site of dysfunction in these patients using myocardial contrast echocardiography. METHODS Women with exertional angina, positive test results on stress imaging, but no coronary artery disease (the study group, n = 18) and age-matched control women also with no coronary artery disease (n = 17) were enrolled. Myocardial contrast echocardiography was performed at rest and during dipyridamole-induced hyperemia. Mean microbubble velocity (β) and myocardial blood volume (A) were measured, and myocardial blood flow (A · β) was computed. In addition, plasma concentrations of eicosanoids, female sex hormones, and C-reactive protein were measured. RESULTS Rest β and myocardial blood flow (A · β) were higher in the study compared with the control women (1.61 ± 0.68 vs. 0.74 ± 0.44, P = .0001, and 157 ± 121 vs. 54 ± 54, P = 0.0001, respectively) despite similar heart rates and systolic blood pressures. After the administration of dipyridamole, whereas the changes in A and A · β were not significantly different between the two groups, β reserve (the ratio of stress β to rest β) was markedly lower in the study group (1.48 ± 0.62 vs. 2.78 ± 0.94, P = .0001). Blood hematocrit, eicosanoids, female sex hormones, glucose, and C-reactive protein were not different between the two groups. CONCLUSIONS Coronary autoregulation is abnormal in patients with syndrome X (higher resting β and myocardial blood flow and lower β reserve), which suggests that the coronary resistance vessels are the site of microvascular abnormality.

A predictive instrument using contrast echocardiography in patients presenting to the emergency department with chest pain and without ST-segment elevation.

Myocardial contrast echocardiography may provide important physiologic information on myocardial perfusion. Most current analysis programs use manual frame grabbing and selecting of the area of interest. This is time-consuming and not highly reproducible. A system for automatic analysis of myocardial contrast echocardiographic studies was developed and evaluated. The program acquires an electrocardiographically gated sequence of end-diastolic images with a frame grabber in a personal computer. The baseline image is subtracted and the videodensity versus time contrast curve parameters are calculated on-line. Fast color-coded analysis is done automatically with a running square window that covers the entire image. A second mode of contrast analysis allows manual selection of multiple regions of interest. The program was evaluated with contrast echo data from open-chest dogs and two demonstrative patients. This myocardial contrast analytic package is an inexpensive, rapid, flexible, convenient, and reproducible on-line method that facilitates myocardial contrast echocardiographic analysis.