Assessment of vascular disease by intravascular ultrasound.
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Animals↗
Biomedical subjects
J C Gurley
Publications and source records attributed to J C Gurley.
Application of a new phased-array ultrasound imaging catheter in the assessment of vascular dimensions. In vivo comparison to cineangiography.
Tomographic imaging techniques such as ultrasound can provide important information in the evaluation of vascular anatomy. Recent technical advances have permitted fabrication of a small (1.83 mm), phased-array, intravascular ultrasonic imaging catheter capable of continuous real-time, cross-sectional imaging of blood vessels. We used this imaging catheter to compare intraluminal ultrasound with cineangiography in the measurement of vascular dimensions in animals and to assess the intraobserver and interobserver variability of the technique. Segmental deformation of vessel anatomy was produced by stenoses created with a tissue ligature or by balloon dilation. The mean value for measurements of vessel diameter was 5.6 mm by cineangiography and 5.7 mm by intravascular ultrasound. The correlation between cineangiography and ultrasound was close (r = 0.98). Mean cross-sectional area by angiography was 28.8 mm2 and 29.6 mm2 (r = 0.96) by ultrasound. Percent diameter reduction produced by the stenoses averaged 48.4% by cineangiography and 40.1% by ultrasound, and the two methods correlated closely (r = 0.89). Correlation between cineangiography and ultrasound for vessel diameter and area before balloon dilation was closer (r = 0.92 and 0.88) than after balloon dilation (r = 0.86 and 0.81). This difference reflected an increase in measured vessel eccentricity following balloon dilation. These data demonstrate that intravascular ultrasound is an accurate and reproducible method for measurement of vascular diameter and cross-sectional area in vivo. Intravascular ultrasound is capable of accurately identifying and quantifying segmental deformation of vascular dimensions produced by either stenoses or balloon dilation.
Angioplasty, Balloon↗
Assessment of the functional significance of coronary stenoses. Is digital angiography the answer?
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Angiography↗
Usefulness of color Doppler flow imaging to distinguish ventricular septal defect from acute mitral regurgitation complicating acute myocardial infarction.
Several studies have found 2-dimensional echocardiography and conventional spectral Doppler ultrasound useful in the assessment of ventricular septal defect (VSD), but few data exist regarding the usefulness of color Doppler flow imaging in evaluating this problem. Thus, the results of color flow imaging performed in 14 patients who presented with a recent acute myocardial infarction (AMI), hemodynamic instability and a new systolic murmur were evaluated. All patients underwent cardiac catheterization for definitive diagnosis, which proved to be VSD in 7 and acute mitral regurgitation in 7. VSD, identified by turbulent flow traversing the ventricular septum during ventricular systole, was correctly identified in all 7 patients with septal rupture. In the remaining 7 patients with a new murmur after AMI, mitral regurgitation was demonstrated as turbulent systolic flow in the left atrium by both color flow imaging and cine ventriculography. In all 14 patients with new murmurs, color flow imaging was 100% accurate for the presence or absence of VSD. Color flow imaging localized the septal defect to the apical septum (3), inferior septum (3) or both inferior and apical septal regions (1), and was 100% concordant for location compared with cineangiography, surgery and conventional Doppler echocardiographic techniques. Color flow imaging was accurate in identifying the presence and location of VSD complicating AMI, and accurately differentiated VSD from mitral regurgitation. Color flow imaging provides safe, rapid diagnosis of VSD complicating AMI, and may alleviate the need for diagnostic right-sided heart catheterization and preoperative cine ventriculography in these seriously ill patients.
Aged↗
A new thrombolytic regimen for acute myocardial infarction using combination half dose tissue-type plasminogen activator with full dose streptokinase: a pilot study. KAMIT Study Group.
Because a previous study utilizing a combination of recombinant tissue-type plasminogen activator (rt-PA) and urokinase demonstrated reduced reocclusion rates compared with rates obtained with rt-PA alone, this study was conducted to determine whether the combination of rt-PA and streptokinase might achieve similar results at reduced cost. Forty patients with acute myocardial infarction were treated with a 1 h infusion of rt-PA (50 mg) and streptokinase (1.5 million U) administered within 6 h (mean 3.6 +/- 1.2) of symptom onset. Emergency coronary arteriography revealed patency of the infarct-related artery in 30 (75%) of 40 patients. With the addition of coronary angioplasty in those who had unsuccessful thrombolytic reperfusion, the early patency rate was increased to 98%. In-hospital mortality rate (2.5%) and the incidence of significant bleeding requiring transfusion (15%) were low. Angiographically documented reocclusion of the infarct vessel occurred in 3 (8%) of 37 patients by day 7. Regional wall motion of the infarct zone improved by 0.9 +/- 0.9 SD/chord (p less than 0.0005), and ejection fraction increased 3.6 +/- 8% units (p less than 0.05) between immediate and day 7 studies. In contrast to the price of full dose rt-PA ($2,300) or rt-PA with urokinase ($3,500), the cost of this regimen was $1,230. This pilot study demonstrates that at half the cost, a combination of half dose rt-PA with full dose streptokinase offers high infarct vessel patency, recovery of ventricular function, a low rate of reocclusion and few bleeding complications.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Pivotal role of aortic valve area calculation by the continuity equation for Doppler assessment of aortic stenosis in patients with combined aortic stenosis and regurgitation.
Aortic regurgitation (AR) may result in overestimation of the aortic pressure gradient by continuous wave Doppler in patients with mixed aortic valve disease. However, few data are available regarding the effect of AR on noninvasive estimates of aortic valve area by the continuity equation. Therefore, 25 patients with angiographically documented severe AR and peak systolic aortic velocities of greater than 2.5 m/s were studied by continuous wave Doppler to determine the accuracy of pressure gradient and aortic valve area calculations in assessing the severity of aortic stenosis (AS) in this patient population. Peak instantaneous pressure gradient showed a general correlation to but was overestimated by Doppler (r = 0.78, Doppler = 0.70 catheter + 19.9) and did not predict aortic valve area. Mean pressure gradient by Doppler correlated more closely with catheter mean gradient (r = 0.86, Doppler = 0.79 catheter + 6.1) but was a poor predictor of the severity of AS. In contrast, the continuity equation accurately predicted the aortic valve area by catheterization (r = 0.92, Doppler = 0.89 catheter -0.08). Thus, the continuity equation provides a reliable estimate of aortic valve area in patients with severe AR and should be used to evaluate the extent of AS in such patients when high systolic aortic velocities are present.
Aortic Valve↗
A practical application of Doppler echocardiography for the assessment of severity of aortic stenosis.
This study evaluated a strategy that makes optimal use of Doppler echocardiography for estimating the severity of valvular aortic stenosis (AS). Fifty-eight patients with no more than moderate aortic insufficiency who underwent cardiac catheterization were evaluated with two-dimensional echocardiography and Doppler velocimetry to determine the peak velocity across the stenotic valve and aortic valve area (AVA) by means of the continuity equation. All 33 peak Doppler velocities of greater than or equal to 4 m/sec had critical AS (AVA less than or equal to 0.8 cm2 at catheterization). Conversely, six of seven patients with Doppler velocities of less than or equal to 3 m/sec had noncritical AS. The patient with a falsely low peak velocity had severely depressed left ventricular function. Doppler velocity alone was inadequate in determining severity of AS for patients with velocities between 3 and 4 m/sec. The continuity equation proved accurate in estimating AVA in the 46 patients for whom catheterization and ultrasound data were sufficient to compare calculated AVA (r = 0.81), and was also accurate for those patients with peak Doppler velocities between 3 and 4 m/sec (r = 0.90). These results suggest that Doppler velocimetry alone is adequate in determining critical vs noncritical AS in many patients, while the continuity equation should be applied for patients with peak velocities between 3 and 4 m/sec as well as in patients with severely depressed cardiac function.
Adult↗
Comparison of simultaneously performed digital and film-based angiography in assessment of coronary artery disease.
This study compared digital angiography (Digital) to conventional cineangiography (Cine) for the diagnosis and quantification of coronary artery disease. Digital and Cine were obtained simultaneously under identical radiographic conditions during routine coronary arteriography. Using visual inspection and manual calipers, four independent observers identified 131 stenoses in 18 patients with multivessel coronary disease. There was no difference in interobserver variability between Digital and Cine during multiple subgroup analyses. Overall, Digital yielded significantly greater estimates of stenosis severity than did either of two separate Cine observations (p less than 0.0001; average difference, 6.25%), but the differences fell below the level of statistical significance when only the group of stenoses 50% or greater were considered. Digital and Cine correlated well for the assessment of stenosis severity (r = 0.88), but linear regression comparisons of multiple subgroups consistently indicated modest overestimation of Cine by Digital. Smaller vessels, branch vessels, and mild lesions increased the likelihood of overestimation by Digital. Digital was highly sensitive for identification of clinically relevant stenoses, but less specific and less predictive than a second observation of Cine. Our results indicate that Digital and Cine are not interchangeable imaging techniques and that potential differences must be considered when Digital is used for clinical decision making.
Angiography↗
Effect of aortic regurgitation on the assessment of mitral valve orifice area by Doppler pressure half-time in mitral stenosis.
Evaluation of the severity of mitral stenosis by continuous-wave Doppler pressure half-time measurement is now well established. However, few data exist regarding the effect of aortic regurgitation (AR) on the validity of this method. Therefore, 73 patients were studied in whom cardiac catheterization and Doppler echocardiographic examinations were performed. Mitral valve orifice area was determined by the Gorlin equation, 2-dimensional echocardiography and Doppler pressure half-time. Doppler pressure half-time and catheterization estimates of mitral valve area correlated well (r = 0.85) in patients without significant mitral regurgitation. This correlation was maintained in patient subgroups with and without significant (at least 2+) AR (r = 0.86 and 0.83, respectively). Similarly, Doppler and 2-dimensional echocardiographic assessment of mitral valve area showed a strong correlation (r = 0.84). Again, the correlation between the 2 methods was similar in patients with and without significant AR (r = 0.86 and 0.82, respectively). Thus, Doppler pressure half-time estimates of mitral valve orifice area are accurate even in patients with AR.
Adult↗
Massive air embolus to the left ventricle: diagnosis and monitoring by serial echocardiography.
Air embolization is an unusual but potentially dangerous complication in left heart catheterization. Microbubbles can be detected with two-dimensional echocardiography, which is often used for this purpose during open heart and bypass surgeries. Permanent neurologic sequelae and hemodynamic collapse can result from embolization of air bubbles to the cerebral and coronary circulations, respectively. Hyperbaric oxygen is the treatment of choice for cerebral air embolization. We present a 39-year-old man who had air embolization during left ventriculography in the form of a large pocket of "pooled" air. The patient was treated with conservative therapy successfully. Two-dimensional transthoracic echocardiography was used to document the presence of the air and follow its dissolution.
Adult↗