Value of multiple echocardiographic views in the evaluation of aortic stenosis in adults by continuous-wave Doppler

Diagnostic Contexts of Echocardiographic Nonapical Window

The long-established utility of multiwindow interrogation in echocardiography (suprasternal notch, right and left sternal border, apex, and subxiphoid) is sometimes not systematically implemented in routine practice. This case series emphasizes the pivotal importance of such practice for the systematic assessment of aortic valve stenosis and in the evaluation of left ventricular outflow tract and the aorta.

Additive value of the right parasternal view for the assessment of aortic stenosis

BACKGROUND

Although Doppler evaluation using a multiplanar method is recommended to assess the severity of aortic stenosis (AS) with transthoracic echocardiography, evidence on the diagnostic significance of a non-apical method is limited. This study aimed to compare the use of the apical with the use of the right parasternal view (RPV) method to evaluate AS severity and to examine the diagnostic significance of performing the RPV method in addition to the apical method during the evaluation.

METHODS

This retrospective observational study included 276 consecutive patients (mean age: 79 ± 10 years; women, 56%) with severe AS (aortic valve area [AVA] ≤1.0cm² ). The severity of AS according to the apical method and that according to the RPV for all subjects were compared, and the significance of performing the RPV method in addition to the apical method was examined. Furthermore, we compared the concordance group, in which the apical and RPV methods indicated matching in severity, and the discordant group, in which the apical and RPV methods did not indicate matching severity.

RESULTS

Peak velocity (V_max ), mean pressure gradient (MG) were significantly higher and the AVA, AVAi, and Doppler velocity index (DVI) were significantly smaller when the RPV was added to the apical view. Performing the RPV method in addition to the apical method significantly decreased the number of low PG AS cases (MG < 40 mmHg) from 69.9% to 65.0% and it increased the number of very severe AS cases (V_max ≥ 5 m/s) from 8.7% to 14.5%. Deviation of Doppler angle was significantly greater in the discordant group compared to the concordant group (22.5 ± .6 vs. 31.8 ± 1.7, p < .001).

CONCLUSIONS

By performing the RPV method in addition to the apical method to determine AS severity, the diagnosis of AS to be resolved in approximately 10% of cases. These results suggest that AS severity may be underestimated by using the apical method alone.

The right parasternal window: when Doppler-beam alignment may be life-saving in patients with aortic valve stenosis

: The need for multiple transducer positions, especially from right parasternal windows, is consistently mentioned in the recommendations for the accurate measurement of peak velocities across a stenotic aortic valve, but yet poorly adopted.We performed a subanalysis of the largest prospective series on the right parasternal acoustic windows in patients with aortic stenosis (330 consecutive) to calculate the degree of misalignment and estimate the potential outcome implication of this often-forgotten approach.The right parasternal view was highly feasible with an average estimated misalignment from the apical view of 14 ± 16 degree; in 10 cases, an estimated misalignment >40 degree. Right parasternal assessment (vs. apical alone) provided a significant reclassification from moderate to severe or even very-severe aortic valve stenosis. Considering a wellestablished survival benefit provided by either percutaneous or surgical valve replacement in patients with severe aortic stenosis the reclassification would result in approximately 1 life-year saved for every 30-35 patients in whom parasternal view were effectively utilized.

Usefulness of the Right Parasternal Echocardiographic View to Improve the Hemodynamic Assessment After Valve Replacement for Aortic Stenosis

Right-parasternal-view (RPV) often provides the best hemodynamic assessment of the aortic-valve-stenosis by echocardiography. However, no detailed study on patients with aortic prosthesis is available. Thus, RPV usefulness is left as an anecdotical notion in this context. We aimed to define feasibility and clinical-impact of RPV before and soon-after percutaneous implantation (TAVI) or surgical (SAVR) aortic-valve-replacement (AVR) for AS. Patients with severe-AS electively referred for AVR between September-2019 and February-2020 were prospectively evaluated. Echocardiographic examinations inclusive of apical and RPV to measure aortic-peak-velocity , gradients and area (AVA) were performed the day before AVR and at hospital discharge and compared by matched-pair-analysis. Forty-seven patients (mean age 79 ± 8 years, 63% female, ejection-fraction 61 ± 6%) referred for SAVR (24 [51%]) or TAVI (23 [49%]) were enrolled. RPV was feasible in 45 patients (96%) before-AVR but in only 32 after-AVR (68%), particularly after SAVR (50%) than TAVI (87% p = 0.005). RPV remained the best acoustic window after TAVI in 75% of cases. Hemodynamic assessment of TAVI, but not SAVR, invariably benefit from RPV versus apical evaluation (aortic-peak-velocity: 2.57 ± 0.39 vs 2.23 ± 0.47 m/sec, p = 0.002; mean gradient: 15 ± 5 vs 12 ± 5 mm Hg, p = 0.01). Five (11%) patients presented severe patient-prosthesis-mismatch, 4 of which were detectable only by RPV. This pilot-experience demonstrates that RPV feasibility is slightly reduced after AVR. RPV can improve the hemodynamic assessment of the prosthetic valve versus apical view, including the detection of patient-prosthesis-mismatch. Furthermore, when RPV is the best acoustic windows in patients with severe AS, it generally remains so after-TAVI.

Incremental value of right parasternal transthoracic echocardiographic examination over the left parasternal approach in assessing ascending aorta size: Additional benefit of three-dimensional echocardiography

BACKGROUND

The ascending aorta (AA) has not been well studied using two-dimensional right parasternal transthoracic echocardiographic examination (2DRPE).

AIM

The aim of the present study was to assess the incremental value of 2DRPE over two-dimensional left parasternal transthoracic echocardiographic examination (2DLPE) in evaluating the size of AA in adult patients (pts) and, secondly, to determine whether live/real time three-dimensional (3D) RPE provided any additional benefit over 2DRPE.

MATERIALS AND METHODS

The AA was successfully imaged by 2DLPE, 2DRPE, and 3D RPE in 87 of 141 (61.7%) pts which comprised of two groups of consecutive pts separated by an interval of 2 weeks.

RESULTS

The maximum length of AA visualized by 2DRPE (4.98 ± 0.89) was larger than 2DLPE in 76/87(87%) pts (P < 0.001). Both the maximum systolic AA inner luminal width and leading edge-to-leading edge width by 2DRPE were greater than 2DLPE (P < 0.001). Similar to other noninvasive imaging modalities where mid-AA width is taken at level of right pulmonary artery, mid-AA width could also be taken at this level by 2DRPE in 79/87(91%) pts since this landmark was visualized during 2DRPE. However, this vessel could be visualized in only 2/87 (2%) pts with 2DLPE. 3DRPE conferred additional benefit over 2DRPE. The maximal AA length by 3DRPE was larger than 2DRPE in 60/87(69%) pts, and the maximal inner lumen and leading edge to leading edge widths were larger in 54/87(62%) and 66/87(76%) pts, respectively.

CONCLUSION

Our preliminary study demonstrates significant incremental value of 2DRPE over 2DLPE in the assessment of AA. 3DRPE confers an additional advantage over 2DRPE.

Feasibility and relevance of right parasternal view for assessing severity and rate of progression of aortic valve stenosis in primary care

BACKGROUND

Right parasternal view (RPV) is important in assessing the severity of aortic stenosis (AS). However, the feasibility and relevance of RPV in primary care is unresolved. Moreover, information regarding the role of RPV in the evaluation of the hemodynamic progression of AS is lacking.

METHODS

Consecutive patients with peak aortic valve velocity (V_max) ≥2.5m/s were prospectively enrolled in a primary care echocardiographic laboratory. Aortic Doppler parameters were evaluated from apical view and RPV.

RESULTS

The total number of enrolled patients was 330 (aged 81±11years, 47% female, left ventricular ejection fraction 64±9%). The RPV was feasible in 275 (83%). V_max and Mean Gradient were significantly higher and aortic valve area was significantly lower from RPV as compared to apical view (p<0.0001 for all). Reclassification of severity towards either moderate or severe AS occurred in 13-26% of patients, according to different criteria, when evaluated from RPV. Among 108 patients (40%) undergoing multiple examinations the rate of progression was lower from the apical approach than from the RPV (0.19±0.20m/s/year vs. 0.24±0.27m/s/year, respectively; p=0.03), and was fast (>0.3m/s/year) in 17 patients (16%) from the apical window vs. 26 patients (24%) from RPV (p<0.0001).

CONCLUSION

Implementing RPV is feasible in primary care and results in a substantial reclassification rate through the entire spectrum of AS severity. Our data also suggest a potential role of Doppler interrogation from multiple windows to improve AS progression assessment.

Doppler Imaging in Aortic Stenosis: The Importance of the Nonapical Imaging Windows to Determine Severity in a Contemporary Cohort

BACKGROUND

Although the highest aortic valve velocity was thought to be obtained from imaging windows other than the apex in about 20% of patients with severe aortic stenosis (AS), its occurrence appears to be increasing as the age of patients has increased with the application of transcatheter aortic valve replacement. The aim of this study was to determine the frequency with which the highest peak jet velocity (Vmax) is found at each imaging window, the degree to which neglecting nonapical imaging windows underestimates AS severity, and factors influencing the location of the optimal imaging window in contemporary patients.

METHODS

Echocardiograms obtained in 100 consecutive patients with severe AS from January 3 to May 23, 2012, in which all imaging windows were interrogated, were retrospectively analyzed. AS severity (aortic valve area and mean gradient) was calculated on the basis of the apical imaging window alone and the imaging window with the highest peak jet velocity. The left ventricular-aortic root angle measured in the parasternal long-axis view as well as clinical variables were correlated with the location of highest peak jet velocity.

RESULTS

Vmax was most frequently obtained in the right parasternal window (50%), followed by the apex (39%). Subjects with acute angulation more commonly had Vmax at the right parasternal window (65% vs 43%, P = .05) and less commonly had Vmax at the apical window (19% vs 48%, P = .005), but Vmax was still located outside the apical imaging window in 52% of patients with obtuse aortic root angles. If nonapical windows were neglected, 8% of patients (eight of 100) were misclassified from high-gradient severe AS to low-gradient severe AS, and another 15% (15 of 100) with severe AS (aortic valve area < 1.0 cm(2)) were misclassified as having moderate AS (aortic valve area > 1.0 cm(2)).

CONCLUSIONS

In this contemporary cohort, Vmax was located outside the apical imaging window in 61% of patients, and neglecting the nonapical imaging windows resulted in the misclassification of AS severity in 23% of patients. Aortic root angulation as measured by two-dimensional echocardiography influences the location of Vmax modestly. Despite increasing time constraints on many echocardiography laboratories, these data confirm that routine Doppler interrogation from multiple imaging windows is critical to accurately determine the severity of AS in contemporary clinical practice.

Relationship between cutoff values of peak aortic valve velocity and those of other Doppler echocardiographic parameters of severity in patients with aortic stenosis and normal flow

BACKGROUND

Previous studies have reported inconsistencies between echocardiographic parameters of severity in aortic valve stenosis (AS). Peak aortic valve velocity (Vmax ) strongly predicts outcome in AS patients. This study was therefore designed to identify the cutoff values of echocardiographic parameters of severity corresponding to a Vmax ≥ 3 m/sec, ≥4 m/sec, 5 m/sec, or 5.50 m/sec in a large cohort of patients with normal flow (NF) AS.

METHODS AND RESULTS

We retrospectively reviewed the echocardiograms of 528 consecutive patients with normal flow (NF) AS, left ventricular (LV) ejection fraction ≥0.50, and NF (stroke volume index > 35 mL/m²). The values of mean pressure gradient (MPG), aortic valve area (AVA), and indexed aortic valve area (IAVA) corresponding to Vmax ≥ 3 m/sec obtained from receiver operating characteristic (ROC) curves analysis were 22 mmHg, 1.15 cm(2) , and 0.60 cm(2) /m(2) , respectively. While a cutoff of Vmax ≥ 4 m/sec to define severe AS was consistent with a value of 39 mmHg for MPG, corresponding values for AVA and IAVA of 0.90 cm² and 0.48 cm²/m², respectively, were substantially different from those recommended in current guidelines. MPG ≥60 and 65 mmHg, AVA ≤0.76 and ≤0.68 cm², and IAVA ≤0.41 and ≤0.35 cm(2) /m(2) were related to a Vmax ≥5 and ≥5.5 m/sec (very severe AS), respectively.

CONCLUSIONS

Guidelines recommended cutoff values for AVA and IAVA are not consistent with those of Vmax and MPG. The results of this study may serve as safeguard in case of apparent inconsistencies between echocardiographic parameters of severity in NF AS.

Usefulness of the right parasternal view and non-imaging continuous-wave Doppler transducer for the evaluation of the severity of aortic stenosis in the modern area

AIMS

Evaluation of the severity of the aortic stenosis (AS) is based on echocardiographic assessment of peak velocity/mean transaortic pressure gradient (MPG) by continuous-wave Doppler and calculation of the aortic valve area (AVA) using the continuity equation. Pioneering echocardiographic studies have shown that MPG should be measured from the apical and right parasternal views using non-imaging continuous-wave Doppler transducer (NI-CWD). Nowadays, ultrasound systems are often sold without NI-CWD due, at least partially, to the improvement of two-dimensional continuous-wave Doppler transducers (2D-CWD). Whether this evolution translated into misevaluation of AS severity was uncertain. Our aim was to evaluate the additional diagnostic value of the use of NI-CWD and the right parasternal view for the evaluation of AS severity in the modern area.

METHODS AND RESULTS

We prospectively evaluated MPG and AVA using the 2D-CWD (apical view) and the NI-CWD (right parasternal view) in 100 patients (78 +/- 5 years, 65% male) consecutively enrolled in an ongoing prospective study. Aortic stenosis severity was graded as mild (AVA > or = 1.5 cm(2)), moderate (1-1.5 cm(2)), or severe (AVA < 1 cm(2)). Misclassification was defined as at least a one grade difference and DeltaAVA > 0.15 cm(2) (twice the intra-observer variability). Feasibility of the 2D-CWD was 100%, MPG 20 +/- 13 mmHg, and AVA 1.52 +/- 0.45 cm(2). Fifty-three per cent had a mild AS, 34% a moderate AS, and 13% a severe AS. Using the NI-CWD, feasibility was 85%, MPG 25 +/- 16 mmHg, AVA 1.33 +/- 0.41 cm(2) (both P < 0.005 compared with 2D-CWD). Thirty-five per cent (n = 30) had a mild AS, 46% (n = 39) a moderate AS, and 19% (n = 16) a severe AS. Using only the 2D-CWD and the apical view, 21 patients (21%) would have been misclassified: 17 as mild instead of moderate AS and 4 as moderate instead of severe AS. In those misclassified patients, MPG was 9 +/- 6 mmHg higher with the NI-CWD and 33% had an MPG difference >10 mmHg.

CONCLUSION

The use of the NI-CWD and the right parasternal view must be performed to evaluate AS severity, especially in case of discrepancy between symptoms and AS severity or for precise evaluation of AS progression.

Clinical usefulness of intravenous albunex for the Doppler assessment of aortic stenosis

Optimal Doppler recordings of stenotic aortic flow are not always easy to obtain. Therefore, the present study investigated how useful intravenous Albunex injections were for improving the Doppler assessment of pressure gradients for aortic stenosis in 20 consecutive patients who underwent Doppler and left-heart catheterization studies within a 1-week period. Continuous-wave Doppler echocardiography was performed using both a 2.5 MHz duplex and a 1.9MHz independent transducer before and after Albunex injections. The maximum and mean pressure gradients were calculated from the highest Doppler velocity tracings using the simplified Bernoulli equation. Pullback catheterization pressure tracings from the left ventricle to the ascending aorta were superimposed for determination of the maximum instantaneous and mean pressure gradients. The Doppler-derived peak and mean pressure gradients showed significant underestimation compared with the catheterization gradients (23+/-17 mmHg and 11+/-7 mmHg, respectively). However, this underestimation disappeared with Albunex injection (-2+/-7 mmHg and -1+/-4mmHg, respectively). Although the Doppler-derived instantaneous and mean pressure gradients correlated well with the catheterization gradients (r=0.909 and r=0.879, respectively), they became much closer with Albunex (r=0.987 and r=0.963, respectively). The improvements in the Doppler-derived peak pressure gradients were significant from an apical window (n=12, 84-120mmHg, p<0.001). but less so from non-apical windows (n=8, 84-91 mmHg, p=0.0146). Accordingly, Albunex is most useful for Doppler recordings of stenotic aortic flow available from the apical window, but not less so from other acoustic windows.

Postoperative exercise tolerance after aortic valve replacement by small-size prosthesis: functional consequence of small-size aortic prosthesis

OBJECTIVES

The objective of this study was to determine whether a small-size valve prosthesis contributes to exercise intolerance, as assessed by VO2 measurement during an exhaustive cycle ergometer exercise.

BACKGROUND

The determinants of exercise capacity after mechanical aortic replacement are not well known. The selection of small valve sizes has, however, been described as an independent predictor of exercise intolerance as assessed by exercise duration. Maximal oxygen uptake (VO2max) is a good index of exercise tolerance.

METHODS

Fourteen patients were eligible, with a mean age of 62 +/- 6 years. Before surgery, the mean left ventricular ejection fraction (LVEF) was 73 +/- 8%. Two valve types with small diameter (19 to 21 mm) were used: Medtronic Hall and St Jude Medical. A healthy sedentary control group (n = 14) paired for age, weight and size was constituted. After one year of follow-up, cardiorespiratory tests were performed. In addition, the gradients through the prostheses were determined by continuous pulse Doppler at rest and immediately after the cardiorespiratory test. RESULTS The exercise tolerance was not significantly different between the control group and patient group: VO2 peak (21.7 vs. 20.4 ml/kg/min; p = 0.42), workloads (115 vs. 93 W; p = 0.13) and ventilatory parameters were similar. The mean and peak gradients at rest and during exercise were not correlated with VO2max.

CONCLUSIONS

Valve replacement by small aortic prosthesis does not seem to be a factor of exercise intolerance as assessed by VO2max in patients without LVEF dysfunction before surgery.

Multiplane transesophageal echocardiographic acquisition of ascending aortic flow velocities: A comparison with established techniques

Acquisition of ascending aortic flow velocities with monoplane transesophageal echocardiography (TEE) have been problematic because of limitations of available imaging planes and alignment of the Doppler beam with aortic flow. The rotatable imaging array of multiplane TEE (Multi TEE) may provide improved alignment with ascending aortic blood flow. The purpose of this study was to establish the validity of maximal aortic flow velocities (VMax) and velocity time integrals (VTI) obtained by a Multi TEE continuous wave Doppler technique by comparison with those obtained by established echocardiographic techniques, suprasternal Doppler (SSD), and monoplane TEE (Mono TEE). Forty-five patients scheduled for elective surgery were prospectively studied. Multi TEE-obtained VMax and VTI were significantly greater (P <.05), 120 +/- 28.9 cm/s and 25.8 +/- 7 cm, than those obtained by the SSD method, 100.2 +/- 28.6 cm/s and 19.8 +/- 6.8 cm, respectively. Bias analysis revealed that Multi TEE better assessed VMax (mean difference -19.7, SD of the difference of 28 cm/s) and VTI (mean difference -5.9, SD of the difference of 6.4 cm) than the SSD method. Multi TEE exhibited values for VMax 10% or greater than those obtained by SSD in 18 (48. 6%) of 37 patients, and Multi TEE was 10% or greater than SSD in 23 (67%) of 37 patients for VTI determination. Values obtained by Multi TEE and Mono TEE showed close agreement. Multi TEE provides a favorable alignment for continuous wave Doppler interrogation of aortic flow and compared favorably to established techniques. This technique expands the utility of TEE to evaluate aortic valvular function and cardiac performance.

Dobutamine Stress Test to Evaluate Different Sizes of Prosthetic Aortic Valves

Dobutamine stress testing and Doppler echocardiography were used to assess hemodynamics in 27 patients aged 16 to 54 years with various sizes and types of aortic valve prosthesis. All patients underwent a symptom-limited treadmill exercise test within two days of the dobutamine test. There was no significant difference in ejection fractions and transvalvular gradients at rest and during dobutamine stress between St. Jude Medical, Medtronic-Hall, and Carbomedics valves. Exercise duration did not differ significantly among the different types of valve. When patients were classified by their underlying lesion, those with aortic stenosis and those with aortic insufficiency had similar ejection fractions and transvalvular gradients at rest and during dobutamine stress. The mean and peak transvalvular gradients at rest and during dobutamine stress were significantly different in patients with different valve sizes but the extent of the increase in gradients during stress was not significant. Linear regression analysis revealed that both peak and mean gradients during dobutamine stress could be predicted by the resting gradients. There was a negative correlation between valve size and gradients at rest and during stress, while there was a significant correlation between exercise duration and valve size. Dobutamine stress echocardiography was useful for studying hemodynamics in patients with aortic valve prostheses and the findings show that valvular size was the main determinant of exercise capacity.

Doppler transesophageal echocardiographic determination of aortic valve area in adults with aortic stenosis

Two-dimensional transesophageal echocardiography has been shown to be an accurate method of measuring aortic valve area in patients with aortic stenosis. The accuracy of Doppler transesophageal echocardiography for this purpose is unknown. Thus 86 consecutive adult patients (mean age 68 +/- 11 years) with calcific (n = 79) or congenital bicuspid (n = 7) AS were studied by biplane or multiplane transesophageal echocardiography. From the transgastric long-axis view, continuous wave Doppler of peak aortic valve velocity and pulsed Doppler of left ventricular outflow tract velocity were determined. Left ventricular outflow tract diameter was measured from a transesophageal echocardiography long-axis view, and cross-sectional area was calculated. Aortic valve area was calculated by the continuity equation. Two-dimensional transesophageal echocardiography was used to directly measure aortic valve area by planimetry of the minimal orifice from a short-axis view. Aortic valve area determination was less feasible by Doppler (62 of 86 patients, or 72%) versus two-dimensional transesophageal echocardiography (81 of 86 patients, or 94%; p < 0.0025) because of the inability to align the continuous wave Doppler beam with the aorta in 24 patients. The feasibility of obtaining aortic valve area by Doppler transesophageal echocardiography improved from the first 43 patients (24 of 43 patients, or 56%) to the latter 43 patients (38 of 43 patients, or 88%; p < 0.0025) and suggests a significant learning curve. In 62 patients, aortic valve area by Doppler and two-dimensional transesophageal echocardiography did not differ (1.30 +/- 0.54 cm2 vs 1.23 +/- 0.46 cm2, p = not significant) and correlated well (r = 0.88; standard error of the estimate = 0.26 cm2; intercept = 0.02 cm2; slope = 1.04; p = 0.0001). Absolute and percent differences between aortic valve area measured by Doppler and two-dimensional transesophageal echocardiography were small (0.18 +/- 0.20 cm2 and 15% +/- 15%, respectively). Mild, moderate, and severe aortic stenosis by two-dimensional transesophageal echocardiography was correctly identified in 93% (28 of 30), 79% (15 of 19), and 77% (10 of 13) of patients by Doppler transesophageal echocardiography, respectively. Doppler transesophageal echocardiography is an accurate method to measure aortic valve area in patients with aortic stenosis and should complement two-dimensional transesophageal echocardiography. The feasibility of Doppler transesophageal echocardiography for aortic valve area determination has a significant learning curve.

Comparison of catheterization and Doppler-derived pressure gradients in a canine model of subaortic stenosis

The relationship between Doppler-estimated and catheterization-measured pressure gradients was examined by repeated-measures linear regression analysis and difference plots in 15 dogs with naturally occurring subvalvular aortic stenosis. Thirty left ventricular outflow tract gradients were compared during sinus rhythm and 142 gradients during premature or postextrasystolic beats for the following pairs of data: (1) mean catheterization gradient versus mean Doppler gradient, (2) maximal instantaneous catheterization gradient versus maximal Doppler gradient, and (3) peak-to-peak catheterization gradient versus maximal Doppler gradient. The correlation between Doppler-derived and catheterization-derived pressure gradients was excellent (r = 0.99; p < 0.001) for the maximal instantaneous (sinus rhythm: standard error of the estimate [SEE] = 5.7 mm Hg; premature and postextrasystolic beats: SEE = 6.7 mm Hg) and mean gradients (sinus rhythm: SEE = 3.6 mm Hg; premature and postextrasystolic beats: SEE = 4.5 mm Hg). There was also a strong correlation between the peak-to-peak catheterization gradient and the maximal Doppler gradient (sinus rhythm: r = 0.99, p < 0.001, SEE = 5.3 mm Hg; premature and postextrasystolic beats: r = 0.97, p < 0.001, SEE = 7.2 mm Hg). Agreement between the two techniques was best for mean gradients and most disparate for the comparisons of maximal Doppler gradients and peak-to-peak catheterization gradients.

Right ventricular apical view--a new window for Doppler echocardiography of aortic valve stenosis

We studied a new Doppler echocardiographic approach in 56 patients with valvular aortic stenosis from the right ventricular apex (AS-RV) and compared the transvalvular gradients with the results of the standard view from the left ventricular apex (AS-LV). AS-RV resulted in good or acceptable velocity curves in 59% of patients. The correlation between the two apical views for the peak/mean gradients were close (r = 0.95/0.96). Using all typical positions for Doppler investigation of aortic stenosis, highest peak gradients were best recorded in five cases by AS-RV. In one woman with a narrow left ventricular cavum and severe aortic stenosis, only AS-RV yielded a technically good spectral curve. Thus, in selected patients--probably those with a small left ventricular cavity or an enlarged right ventricle--AS-RV may be the best window or even the only possibility in Doppler investigation of aortic valve stenosis.

Comparison of Doppler echocardiographic methods with heart catheterisation in assessing aortic valve area in 100 patients with aortic stenosis

OBJECTIVE

To examine the practicability and accuracy of Doppler echocardiographic methods in determining aortic valve area.

METHODS

Aortic valve areas determined by three methods using Doppler echocardiography (applying the continuity equation and the modified Gorlin formula using data from Doppler echocardiography and right heart catheterisation) were compared with values obtained by heart catheterisation.

PATIENTS

100 consecutive patients with aortic stenosis aged between 34 and 83 years (mean (SD) 66 (10)).

RESULTS

Differences in individual patients' measurements of aortic valve area by the three Doppler techniques varied by up to 0.56 cm2 compared with values obtained by heart catheterisation. On average, values obtained from Doppler echocardiographic methods lay up to 51% below and 78% above those obtained by heart catheterisation.

CONCLUSIONS

All three Doppler echocardiographic methods were practicable in routine clinical practice for patients of all ages, but they were of limited accuracy when compared with the aortic valve areas found invasively using the invasive Gorlin equation. However, these deviations may not always be due to inadequacies of the Doppler methods: they could also be caused by limitations in the Gorlin formula. Doppler methods can be repeated if required, they allow examination of the morphology of the valve, and they subject the patient to considerably fewer risks than the invasive procedure. An adequate strategy in determining the severity of aortic valve stenosis would be to calculate the valve area by Doppler echocardiography as well as considering the valvar aortic pressure gradient. The valve area alone should not be relied on exclusively, as has been the increasing practice in the past few years.

Accuracy and precision of MR velocity mapping in measurement of stenotic cross-sectional area, flow rate, and pressure gradient

Reliability of magnetic resonance (MR) velocity mapping to assess severity of stenosis was assessed in vitro. Steady flow at different flow rates through five stenoses with a central orifice area ranging from 17 to 176 mm2 was measured with velocity mapping performed perpendicular to the stenotic jet. Besides determination of the stenotic cross-sectional area and flow rate, the pressure gradient was calculated with the modified Bernoulli equation and compared with manometer measurements. Cross-sectional areas were measured with an accuracy of > or = 76%, a precision of > or = 91%, and an error of < or = 19 mm2. Flow rates had an accuracy of > or = 72%, a precision of > or = 94%, and an error of < or = 1.4 L/min. The modification of the Bernoulli equation limited its reliability to stenoses with areas of 35-113 mm2. Pressure gradients were calculated with an accuracy of > or = 80%, a precision of > or = 88%, and an error of < or = 15 mm Hg. The method was applied in a single patient with aortic stenosis and gave estimates that agreed with those obtained by heart catheterization.

Prolongation of isovolumetric relaxation time as assessed by Doppler echocardiography predicts doxorubicin-induced systolic dysfunction in humans

A reasonably sensitive and specific noninvasive test for doxorubicin cardiotoxicity is needed. In addition, few data exist on the short- and long-term effects of doxorubicin on diastolic filling. To determine if pulsed Doppler indexes of diastolic filling could predict doxorubicin-induced systolic dysfunction, 26 patients (mean age 48 +/- 12 years) were prospectively studied before receiving chemotherapy (control) and 3 weeks after obtaining cumulative doses of doxorubicin. In nine patients developing doxorubicin-induced systolic dysfunction (that is, a decrease in ejection fraction by greater than or equal to 10 ejection fraction units to less than 55%), the isovolumetric relaxation time was prolonged (from 66 +/- 18 to 84 +/- 24 ms, p less than 0.05) after a cumulative doxorubicin dose of 100 to 120 mg/m2. This prolongation preceded a significant decrease in ejection fraction. Other Doppler indexes of filling were impaired after doxorubicin therapy but occurred simultaneously with the decrease in ejection fraction. A greater than 37% increase in isovolumetric relaxation time was 78% (7 of 9) sensitive and 88% (15 of 17) specific for predicting the ultimate development of doxorubicin-induced systolic dysfunction. In 15 patients studied 1 h after the first treatment, doxorubicin enhanced Doppler indexes of filling and shortened isovolumetric relaxation time. In 22 patients, indexes of filling remained impaired and isovolumetric relaxation time was prolonged 3 months after the last doxorubicin dose. In conclusion, doxorubicin-induced systolic dysfunction is reliably predicted by prolongation of Doppler-derived isovolumetric relaxation time. Early after administration, doxorubicin enhances filling and isovolumetric relaxation time. The adverse effects of doxorubicin on both variables persist at least 3 months after cessation of treatment.

Subclavian artery stenosis masquerading as prosthetic aortic stenosis: a potential source of confusion in Doppler evaluation of aortic valve disease

In this case report we describe a patient with a prosthetic aortic valve in whom a high-velocity signal from a right subclavian artery stenosis initially was mistaken for the aortic jet signal. Differences in the shapes of the jets obtained from an apical and right supraclavicular position suggested different origins of these two high-velocity systolic signals. Correct identification of the origin of each signal was possible with pulsed Doppler recordings of the subclavian artery and high pulse-repetition-frequency pulsed Doppler interrogation of the aortic valve.

Mitral and aortic valvular flow: quantification with MR phase mapping

When magnetic resonance phase mapping is used to quantitate valvular blood flow, the presence of higher-order-motion terms may cause a loss of phase information. To overcome this problem, a sequence with reduced encoding for higher-order motion was used, achieved by decreasing the duration of the flow-encoding gradient to 2.2 msec. Tested on a flow phantom simulating a severe valvular stenosis, the sequence was found to be robust for higher-order motion within the clinical velocity range. In eight healthy volunteers, mitral and aortic volume flow rates and peak velocities were quantified by means of phase mapping and compared with results of the indicator-dilution technique and Doppler echocardiography, respectively. Statistically significant correlations were found between phase mapping and the other two techniques. Similar studies in patients with valvular disease indicate that phase mapping is also valid for pathologic conditions. Phase mapping may be used as a noninvasive clinical tool for flow quantification in heart valve disease.

Two-dimensional transesophageal echocardiographic determination of aortic valve area in adults with aortic stenosis

To determine if aortic stenosis severity could be accurately measured by two-dimensional transesophageal echocardiography (TEE), 62 adult subjects (mean age 66 +/- 12 years) with aortic stenosis had their aortic valve area (AVA) determined by direct planimetry using TEE, and with the continuity equation using combined transthoracic Doppler and two-dimensional echocardiography (TTE). Eighteen subjects had AVA calculated by the Gorlin method during catheterization. An excellent correlation (r = 0.93, SEE = 0.17 cm2) was found between AVA determined by TEE (mean 1.24 +/- 0.49 cm2; range 0.40 to 2.26 cm2) and TTE (mean 1.23 +/- 0.46 cm2; range 0.40 to 2.23 cm2). The absolute (0.13 +/- 0.12 cm2) and percent (10.8 +/- 8.9%) differences between AVA determined by TEE versus TTE were small. Excellent correlations between AVA by TEE and TTE were also found in subjects with normal systolic function (r = 0.95, SEE = 0.14 cm2; n = 38) and impaired function (r = 0.91, SEE = 0.21 cm2; n = 24). AVA determined by catheterization correlated better with AVA measured by TEE (r = 0.91, SEE = 0.15 cm2) than AVA measured with TTE (r = 0.84, SEE = 0.19 cm2). These data demonstrate that AVA can be accurately measured by direct planimetry using TEE in subjects with aortic stenosis. TEE may become an important adjunct to transthoracic echocardiography in the assessment of aortic stenosis severity.

Two-Dimensional Doppler Echocardiographic Derived Aortic Valve Area in Aortic Stenosis

Two-dimensional Doppler echocardiography provides qualitative and quantitative information in patients with aortic stenosis. An illustrative case is presented that describes the use of combining these techniques: two-dimensional echo for valve morphology, left ventricular outflow tract area and left ventricular systolic function, pulsed Doppler for estimating cardiac output, and continuous wave Doppler to derive peak and mean systolic gradients. In this patient, continuous-wave Doppler underestimated the severity of stenosis, based on the systolic peak and mean gradient due to reduction in the cardiac output. Patients who have aortic stenosis and ventricular dysfunction should also have the severity of the stenosis determined by estimating the valve orifice area with the continuity equation.

Doppler echocardiography in aortic stenosis: feasibility and clinical impact

The clinical utility of Doppler echocardiography for the assessment of aortic stenosis was prospectively studied in 425 consecutive patients referred to the echocardiography laboratory over 1 year with the clinical diagnosis of aortic stenosis. Optimal peak Doppler velocities were obtained in 405 (95%) patients of all ages. In 108 patients, the severity of aortic stenosis as determined by subsequent cardiac catheterization was compared with that found by Doppler assessment. Categorization of severity was concordant in 8 (89%) of 9 cases of mild aortic stenosis and in 28 (78%) of 36 cases of severe aortic stenosis, but there was considerable diagnostic overlap in cases of moderate stenosis. Forty-nine patients with mild aortic stenosis as determined clinically had moderate or severe stenosis as assessed by Doppler; 7 (14%) of these patients underwent subsequent replacement of the aortic valve. Increased aortic velocity, as determined by Doppler, was associated with a significant incidence of subsequent (mean follow-up period, 22 months) cardiac events (cardiac death, aortic valvar replacement, New York Heart Association functional class III or IV). Patients with mild aortic stenosis as assessed by Doppler (peak aortic velocity less than 2.5 m/sec) had greater than 95% event-free survival at 1 year and rarely required cardiac catheterization. Conversely, only 45% of patients with severe aortic stenosis as determined by Doppler were free of a cardiovascular event at 1 year. Although the noninvasive assessment of aortic stenosis should ideally include determination of the area of the aortic valve and the mean aortic gradient by Doppler echocardiography, this is not always possible. Prognostic information derived from peak aortic velocity alone is clinically useful. It has the additional advantage that it is much less laborious and time-consuming to obtain and is obtainable in almost all (99%) patients.

Immediate and short-term effects of aortic balloon valvuloplasty on left ventricular diastolic function and filling in humans

The effect of aortic balloon valvuloplasty on left ventricular diastolic function and filling was investigated in 44 adult patients with severe aortic stenosis. Two-dimensional and Doppler echocardiography was performed in all patients before and 24 h after valvuloplasty. In 19 patients (short-term group) repeat studies were performed at 3 (n = 2) and 6 (n = 17) months. Left ventricular relaxation, chamber stiffness and filling were assessed in 16 patients (immediate post-valvuloplasty group) before and immediately after valvuloplasty by simultaneous micromanometer left ventricular pressure tracings and echocardiograms. Immediately after valvuloplasty, relaxation was slightly impaired in the immediate post-valvuloplasty group, as reflected by the isovolumic relaxation time constant (56 +/- 26 to 68 +/- 39 ms; p less than 0.01) and maximal negative dP/dt (2,063 +/- 640 to 1,767 +/- 495 mm Hg/s; p less than 0.001). The chamber stiffness constants and diastolic filling dynamics were unchanged immediately after valvuloplasty. Twenty-four hours after valvuloplasty, patients without mitral regurgitation (n = 24) showed increases in the peak early filling velocity (72 +/- 31 to 83 +/- 28 cm/s; p less than 0.05) and peak early to atrial filling velocity ratio (0.8 +/- 0.6 to 1.0 +/- 0.7; p less than 0.05). However, in patients with mitral regurgitation (n = 20), the diastolic filling dynamics were not significantly changed. In the short-term group at the 3 to 6 month follow-up period, patients without mitral regurgitation (n = 12) showed striking increases compared with pre-valvuloplasty values in the peak early filling velocity (66 +/- 21 to 93 +/- 31 cm/s; p less than 0.02), peak early to atrial filling velocity ratio (0.6 +/- 0.2 to 0.9 +/- 0.4; p less than 0.02) and early time-velocity integral (9 +/- 4 to 16 +/- 6 cm; p less than 0.002). In patients with mitral regurgitation (n = 7) decreases occurred in the peak early filling velocity (123 +/- 32 to 106 +/- 28 cm/s; p less than 0.05) and peak early to atrial filling velocity ratio (1.5 +/- 0.7 to 1.1 +/- 0.6; p less than 0.05). Functional class in hospital improved after valvuloplasty (3.1 +/- 1.0 to 2.6 +/- 0.9; p less than 0.001) and correlated modestly with the percent decrease in Doppler-derived peak gradient (rs = 0.41, p less than 0.02) and mean gradient (rs = 0.36, p less than 0.05), but did not correlate with changes in aortic valve area, left ventricular ejection fraction or diastolic filling variables.(ABSTRACT TRUNCATED AT 400 WORDS)

Doppler echocardiographic evaluation of congenital cardiac disease. An introduction

M-mode and two-dimensional echocardiography have greatly enhanced the evaluation of animals with congenital cardiac disease. Structural abnormalities can be seen and hemodynamic alterations inferred, e.g., ventricular wall concentric hypertrophy indicating pressure overload to the respective ventricle. Interrogation of the diseased heart by Doppler echocardiography allows acquisition of more direct hemodynamic information without cardiac catheterization, which enables the clinician to give a more precise description of a congenital abnormality. The purpose of this study is to illustrate and describe abnormal blood-flow patterns in selected congenital cardiac defects in animals. Basic background information concerning Doppler echocardiographic principles, flow patterns, and calculations will be briefly discussed. For more detailed descriptions other references should be sought. Interpretation of Doppler echocardiography in animals is based primarily on data derived from human studies since studies involving measurable numbers of veterinary patients have not yet been completed.

Doppler ultrasound evaluation of valvar pulmonary stenosis from multiple transducer positions in children requiring pulmonary valvuloplasty

The modified Bernoulli equation has been used to determine the peak pressure difference across stenotic pulmonary valves. The direction of the poststenotic jet may be eccentric in relation to the axis of the pulmonary artery. Consequently, the maximal velocity obtained from the parasternal transducer position may inaccurately estimate peak pressure difference. Thus, Doppler-derived estimates of pressure difference from the parasternal, subcostal, apical, and suprasternal notch transducer positions were compared with peak-to-peak pulmonary artery to right ventricle catheter withdrawal pressure differences in 24 patients admitted for pulmonary valvuloplasty. Suprasternal, subcostal or apical transducer positions produced higher maximal velocities than the parasternal transducer position in 12 of 24 patients when the studies were performed before cardiac catheterization and in 8 of 12 patients when performed during cardiac catheterization. The Doppler-derived estimates using the highest maximal velocity predicted catheterization pressure difference accurately when the measurements were not performed simultaneously (y = 1.05x - 3.3, r = 0.86, standard error of the estimate +/- 18.7 mm Hg) and the correlation was closer when the measurements were performed simultaneously (y = 1.09x - 2.7, r = 0.97, standard error of the estimate +/- 9.4 mm Hg). The transducer position that yielded the highest maximal velocity in an individual patient was the same before and after valvuloplasty. In all groups, the correlation with pressure at cardiac catheterization was improved by using the highest maximal velocity rather than the parasternal maximal velocity.

Noninvasive maternal stroke volume and cardiac output determinations by pulsed Doppler echocardiography

Sixteen obstetric patients with pulmonary artery catheters were studied by two-dimensional and pulsed Doppler echocardiography to compare prospectively pulsed Doppler-and thermodilution-derived estimations of left ventricular stroke volume and cardiac output. Systolic aortic flow velocity waveforms were obtained by pulsed Doppler ultrasound from the apical five-chamber echocardiographic window. Aortic diameters were obtained by two-dimensional echocardiography from the left parasternal long axis view. The mean (+/- SEM) aortic diameter averaged 2.1 +/- 0.1 cm, with a mean calculated aortic valve area of 3.6 +/- 0.2 cm2. The mean aortic flow velocity integral was 21.8 +/- 0.8 cm. This information was used to calculate aortic stroke volume and cardiac output. Thermodilution- and Doppler-derived estimations for maternal stroke volume (r = 0.86) and cardiac output (r = 0.94) were significantly correlated when aortic diameter measurements based on a leading vessel edge method were used. Our findings verify the accuracy of an important noninvasive technique for quantitating maternal stroke volume and cardiac output by pulsed Doppler echocardiography. This methodology should provide an alternative approach to invasive monitoring in the study of normal and abnormal maternal circulatory hemodynamics.

Quantitative applications of Doppler cardiography in congenital heart disease

Doppler ultrasound has rapidly become a valuable tool in the noninvasive investigation of cardiac hemodynamics. Although based on secure principles, accurate application of this methodology to quantitative measurements necessitates a thorough understanding of both Doppler physics and instrumentation. Over the past several years a large body of clinical and animal data verifying the accuracy of Doppler determination of pressure and flow data at various sites in the cardiovascular system, as well as the potential sources of error in acquisition and interpretation of blood velocity recordings, has been published. Quantitative use of Doppler in congenital heart disease, with emphasis on limitations of existing studies and issues particular to this patient population, is reviewed.

Echocardiographic assessment of aortic valve area in elderly patients with aortic stenosis and of changes in valve area after percutaneous balloon valvuloplasty

Echocardiographic studies, adequate for analysis of aortic valve area using the continuity equation, were obtained in 31 patients aged greater than or equal to 60 years who were undergoing catheterization for assessment of suspected aortic stenosis. Catheterization-determined aortic valve area was 0.74 +/- 0.30 cm2 (mean +/- SD) and Doppler-determined aortic valve areas were 0.68 +/- 0.27 and 0.65 +/- 0.27 cm2, depending on whether peak or mean velocities, respectively, were entered into the continuity equation. There were significant correlations between both of the Doppler-derived and the catheterization-determined aortic valve areas (r = 0.86, p less than 0.001 for both the continuity equation employing peak velocities and the continuity equation employing mean velocities) which were demonstrated to be linear by F test (catheterization area = -0.03 + 1.13 X Doppler area determined using peak velocities, SEE = 0.163 cm2, p less than 0.001; and catheterization area = -0.02 + 1.16 X Doppler area determined using mean velocities, SEE = 0.165 cm2, p less than 0.001). Both sets of correlations had linear regression parameters meeting the conditions for identity. Significant linear correlations were also noted between the non-invasive measurements of aortic valve excursion, ventricular ejection time, time to one-half carotid upstroke, maximal Doppler velocity and maximal Doppler gradient and catheterization aortic valve area, but the correlations were less tight than those between valve areas determined by catheterization and by Doppler continuity equation. Ten of the patients underwent percutaneous balloon aortic valvuloplasty. There were significant linear correlations between aortic valve areas determined by Doppler and catheterization methods both before valvuloplasty (r = 0.77, p = 0.01; p less than 0.001 by F test, SEE = 0.134 cm2) and after valvuloplasty (r = 0.85, p less than 0.01; p = 0.0001 by F test, SEE = 0.161 cm2). Linear regression parameters met the conditions for identity. There was also a significant linear correlation between catheterization and Doppler measurements of absolute change in aortic valve area (r = 0.79, p less than 0.01; p less than 0.001 by F test, SEE = 0.11 cm2). Aortic valve area can be determined reliably by continuity equation in elderly patients. In addition, results of balloon valvuloplasty, measured by changes in catheterization-determined aortic valve area, are accurately reflected by changes in aortic valve area determined using the continuity equation.

Estimation of outflow tract pressure gradients by continuous wave Doppler in children

Continuous wave Doppler echocardiography was used to estimate pressure gradients in 27 children with right or left ventricular outflow tract obstruction. The pressure gradients predicted by Doppler were compared to peak-to-peak and instantaneous gradients measured at cardiac catheterization. When the Doppler study was performed the pressure gradient obtained at catheterization was not known to the examiner. A correlation coefficient of 0.76 was found for the comparison between the Doppler predicted gradient and the peak-to-peak gradient and 0.78 for the comparison with the instantaneous pressure gradient. Clinically significant obstructions could be reliably separated from insignificant obstructions by the Doppler technique.

Cardiac Doppler

Doppler echocardiography, when used alone and in conjunction with two-dimensional echocardiography, provides information pertaining to intracardiac blood flow dynamics. Pulsed Doppler techniques have the ability to localize intracardiac blood flow velocity patterns. This allows for the interrogation of specific cardiac chambers for both normal and abnormal flow. Disorders such as intracardiac shunts, valvular regurgitation, and stenotic lesions can be detected and evaluated with this technique. The location, duration, and timing of flow velocity information can be assessed, allowing diagnoses to be made with this technique that could not be made with imaging alone. Continuous-wave Doppler allows for evaluation of maximal velocity information, which can be used to quantitate intracardiac pressure information such as the gradient across a stenotic valve or the pressure drop across a regurgitant valve. A new twodimensional color flow mapping system provides a noninvasive method for evaluating intracardiac blood flow in ways that previously could only be accomplished through the use of angiographic techniques. This technique has shown promise in allowing evaluation of blood flow dynamics never before available with noninvasive techniques. When combined with two-dimensional echocardiography, Doppler echocardiographic techniques provide information which allow for a more complete and accurate noninvasive evaluation of cardiovascular disorders.

Estimation of the peak-to-peak pressure gradient in aortic stenosis by Doppler echocardiography

The present study was designed to develop a new Doppler method to estimate noninvasively the peak-to-peak pressure gradient in patients with aortic stenosis. It was carried out in two steps. In the first study, left heart catheterization data were analysed in 58 patients with aortic stenosis. The peak pressure gradient correlated highly with (r = 0.98) but overestimated significantly the peak-to-peak pressure gradient. The averaged pressure gradient (average of the peak gradient and the gradient at the peak aortic pressure) was found to approximate closely the peak-to-peak pressure gradient (r = 0.99) with a good separation between significant and insignificant aortic stenosis. The ratio of the left ventricular ejection time over the aortic pressure descending time was studied and the beginning of the late one-third systole was chosen as the point for determining the late systolic gradient by the Doppler technique. In the second study, Doppler echocardiography and cardiac catheterization were performed in 35 patients with aortic stenosis. The Doppler-determined peak pressure gradient correlated highly with catheterization-measured peak pressure gradient (r = 0.95) but overestimated significantly the peak-to-peak pressure gradient. The Doppler-determined averaged pressure gradient (average of the peak and the late systolic gradients) estimated accurately the peak-to-peak gradient (r = 0.97) with a good separation between significant and insignificant aortic stenosis. These results demonstrate the limitations of the peak pressure gradient measurement and the reliability of the Doppler-determined averaged pressure gradient for estimation of the peak-to-peak pressure gradient.

Continuous-wave Doppler in children with ventricular septal defect: noninvasive estimation of interventricular pressure gradient

Continuous-wave Doppler was used to estimate the pressure gradient between the right and left ventricles in 28 children with ventricular septal defect (VSD). Doppler measurement of maximal velocity was performed during cardiac catheterization and the Doppler-predicted gradient was compared with the peak-to-peak gradient measured simultaneously by catheter. Doppler gradients ranged from 10 to 71 mm Hg and correlated well with measured gradient (r = 0.97, p greater than or equal to 0.001). Fourteen patients had isolated VSD, and in these patients Doppler measurements of gradient allowed accurate estimation of right ventricular pressure (r = 0.93). There was an inverse correlation between the ratio of pulmonary to systemic resistance and maximal velocity (r = -0.77). Thus, continuous-wave Doppler is an accurate means of measuring instantaneous VSD pressure gradient in children with congenital heart disease and can be used to estimate the right ventricular and pulmonary artery pressure in children with isolated VSD. This noninvasive method can be used to distinguish restrictive from nonrestrictive VSD.

Doppler hemodynamic evaluation of prosthetic (Starr-Edwards and Björk-Shiley) and bioprosthetic (Hancock and Carpentier-Edwards) cardiac valves

One hundred thirty-four patients with prosthetic or bioprosthetic heart valves were investigated with Doppler echocardiography to determine normal values for commonly used prosthetic valves and to test the specificity of abnormal Doppler findings. In 70 patients the aortic valves had been replaced and in 64 the mitral valves had been replaced. Gradients across prostheses in the aortic position were calculated from maximal velocity. Peak calculated aortic transvalvular gradients in normal subjects were 22 +/- 10 mm Hg in 33 Björk-Shiley valves, 23 +/- 10 mm Hg in 27 porcine valves and 29 +/- 13 mm Hg in 6 Starr-Edwards valves. Mild aortic regurgitation was seen in 42% of Björk-Shiley valves, 26% of porcine valves and 2 of 6 Starr-Edwards valves. Mitral valve orifice was calculated by the pressure half-time method. In clinically normal patients with mitral valve prostheses, the effective mitral valve orifice was 2.5 +/- 0.8 cm2 in 35 Björk-Shiley valves, 2.1 +/- 0.7 cm2 in 17 porcine valves, and 2.0 +/- 0.3 cm2 in 10 Starr-Edwards valves. Mitral regurgitation was found in 11% of Björk-Shiley valves, 19% of porcine valves and 30% of Starr-Edwards valves. Repeat studies at 2 weeks to 14 months revealed no difference in 8 aortic and 14 mitral prostheses. Seven aortic and 4 mitral valves functioned abnormally as determined by Doppler, and the abnormal function was confirmed in each at surgery or at cardiac catheterization.(ABSTRACT TRUNCATED AT 250 WORDS)