Intertest variability of echocardiographic and chest X-ray measurements: implications for decision making in patients with aortic regurgitation

Specificity of Doppler echocardiography for the assessment of changes in valvular regurgitation: comparison of side-by-side versus serial interpretation

OBJECTIVES

We sought to determine the specificity of two different methods for assessing change in aortic (AR), mitral (MR) and tricuspid (TR) valvular regurgitation.

BACKGROUND

Echocardiographic imaging with Doppler is the standard noninvasive diagnostic tool for assessing valvular structure and function. Change can be assessed using either independent evaluations (serial) or using a side-by-side comparison.

METHODS

Subjects were from the placebo arm of a randomized, double-blind, clinical trial. Three echocardiograms over 10 months were performed. An initial and three-month echocardiogram were read as independent groups, blinded to all parameters except sequence. The initial and 10-month echocardiograms were read side-by-side, blinded to all parameters including sequence.

RESULTS

Two hundred nineteen predominantly healthy, obese, white, middle-aged women had initial and three-month echocardiograms (acquisition interval 105 +/- 28 days) evaluated by the serial method (mean 167 +/- 61 days between interpretations). The same subjects had the initial and 10-month studies (acquisition interval 303 +/- 27 days) compared side-by-side. The specificity of the serial versus side-by-side method for determining change in MR grade was 55.8% versus 93.2% (p < 0.001); TR: 63.8% versus 97.6% (p < 0.001) and AR: 93.7% versus 97.6 (p = 0.08). Notably, most of the change occurred in a range (none versus physiologic/mild) that has limited clinical significance. Furthermore, the percentage of echocardiograms interpreted as nonevaluable was lower with the side-by-side method for MR (5.0% vs. 16.0%, p = 0.06), TR (4.6% vs. 15.5%, p < 0.001) and AR (4.1% vs. 12.3%, p = 0.002).

CONCLUSIONS

The side-by-side method of assessing change in valvular regurgitation appears to be the more reliable method with a higher specificity and minimal data loss.

Prognostic implications of qualitative assessment of left ventricular function compared to simple routine quantitative echocardiography

OBJECTIVE

To compare the prognostic value of qualitative estimates of left ventricular function with that of routine simple quantitative indices used in echocardiography.

DESIGN

Retrospective follow up study.

SETTING

University hospital.

PATIENTS

The records of 2,964 patients who had undergone echocardiography and who could be traced on the family health services register were examined; 919 cases were included in the study, and a further 458 were used to validate the statistical models for prognostic assessment. There were 928 exclusions on the basis of referral for or diagnosis of alternative conditions, and 659 because of incomplete collection of the qualitative and quantitative data used in the study.

MAIN OUTCOME MEASURE

Survival over the study period.

RESULTS

A qualitative "eyeball" estimate of left ventricular function was of prognostic significance (relative risk of poor v good, 2.248; P << 0.001; 95% confidence interval 1.620 to 3.119). None of the quantitative echocardiographic indices was of independent prognostic significance when all variables were tested simultaneously in the regression model.

CONCLUSIONS

A qualitative echocardiographic estimate of left ventricular dysfunction is of prognostic value, supporting the view of many cardiologists who use their overall impression of left ventricular function at echocardiography as the basis for treatment decisions.

Aortic regurgitation complicated by extreme left ventricular dilation: long-term outcome after surgical correction

OBJECTIVES

This study sought to determine the outcome of aortic valve replacement for aortic regurgitation complicated by extreme left ventricular dilation.

BACKGROUND

Aortic valve replacement has been recommended in aortic regurgitation with extreme left ventricular dilation (diastolic dimension >/= 80 mm), but extreme left ventricular dilation raises concern about irreversible left ventricular dysfunction.

METHODS

Thirty-one patients with a preoperative echocardiographic diastolic dimension >/= 80 mm (group 1) undergoing operation for severe isolated aortic regurgitation between 1980 and 1989 were compared with 188 patients with a diastolic dimension <80 mm operated on during the same period (group 2).

RESULTS

Preoperatively, extreme left ventricular dilation was seen only in male patients and was associated with a reduced ejection fraction (43 +/- 12% vs. 53 +/- 11% [mean +/- SD], p < 0.0001). The postoperative outcome of group 1 was compared with that of male patients in group 2 (group 2M, n = 144). The operative mortality rates for groups 1 and 2M were 0% and 5.6%, respectively (p = 0.35). Late survival in operative survivors was similar in groups 1 and 2M, but compared with expected survival, an excess mortality was observed for group 1 (p = 0.024). Preoperative ejection fraction, but not diastolic dimension, independently predicted late survival and postoperative ejection fraction. Postoperatively, groups 1 and 2M showed a similar improvement in ejection fraction, but persistent left ventricular enlargement was more frequent in group 1.

CONCLUSIONS

Extreme left ventricular dilation due to aortic regurgitation is observed in male patients and is frequently associated preoperatively with a reduced ejection fraction but is not a marker of irreversible left ventricular dysfunction. Operative risk and late postoperative survival are acceptable in these patients, although a late excess mortality, predicted best by preoperative ejection fraction, is observed. Therefore, extreme left ventricular dilation is not a contraindication to operation, which should be performed before left ventricular dysfunction occurs.

Regression of left ventricular hypertrophy with long-term treatment of nifedipine in systemic hypertension

We investigated the regression of left ventricular (LV) hypertrophy with long-term treatment of nifedipine in patients with systemic hypertension. Echocardiograms of the LV were obtained in nine patients before and at a mean of 50 months (13-105 months) after nifedipine monotherapy (30-60 mg/day). Nifedipine significantly reduced both systolic and diastolic blood pressures (BP) by a mean of -46 mmHg and -21 mmHg, respectively. With systemic BP reduction, LV mass was significantly reduced by a mean of -15%, associated with a decrease in LV posterior wall thickness and end-diastolic dimension. There was no significant change in LV fractional shortening. We conclude that nifedipine may cause regression of LV hypertrophy in systemic hypertension, and that reversal of the increase in LV mass could be maintained during long-term nifedipine treatment.

Effects of long-term vasodilator therapy on electrocardiographic abnormalities in chronic aortic regurgitation

Electrocardiographic abnormalities develop in patients with chronic aortic regurgitation (AR). Although vasodilator drugs may reduce left ventricular (LV) volume overload, the effects of such therapy on electrocardiographic abnormalities have not been previously evaluated. Accordingly, electrocardiograms were analyzed before and after double-blind, randomized administration of either hydralazine or placebo in 54 patients with chronic AR. These patients were without limiting symptoms and had preserved ejection fraction on entry in the study. The magnitude of ST-segment depression and Romhilt-Estes point score for LV hypertrophy were assessed. Baseline ST depression and LV hypertrophy scores in the placebo and hydralazine groups were not significantly different. At follow-up, after a mean of 19 +/- 6 months, there was a significant reduction in ST depression in patients taking hydralazine (n = 28) compared with patients given placebo (n = 26): -0.023 +/- 0.044 vs 0.029 +/- 0.055 mV, respectively (p = 0.0001); and in the LV hypertrophy score (-1.1 +/- 2.2 vs 0.9 +/- 2.3 points, respectively; p = 0.002). Hydralazine-treated patients also had significant decreases in LV end-diastolic and end-systolic volume indexes, and a significant increase in ejection fraction. These results suggest that such vasodilator therapy may be beneficial in patients with chronic AR.

Management of asymptomatic chronic aortic regurgitation with left ventricular dysfunction: a decision analysis

STUDY OBJECTIVE

To determine the optimal strategy for the timing of aortic valve replacement in patients with chronic, severe aortic regurgitation with left ventricular dysfunction.

DESIGN

Decision analysis comparing early surgery (timed at the onset of left ventricular dysfunction) with delayed surgery (timed at the onset of symptoms) using data from the literature and expert opinion for variables in a representative case scenario (40-year-old man with bicuspid aortic valve disease).

SETTING

Tertiary care center doing valve replacement surgery.

MEASUREMENTS AND MAIN RESULTS

The early-surgery approach was preferred based on quality-adjusted life years. Sensitivity analysis showed that the result was not affected by the following variables within their derived ranges: rate of symptom development after onset of left ventricular dysfunction for the delayed-surgery approach, perioperative mortality for both approaches, and occurrence of major nonfatal stroke or congestive heart failure for both approaches. Although the decision was sensitive to the yearly postoperative mortality rates, the delayed-surgery operative mortality rate had to be almost as low as the early-surgery rate to change the preference to the delayed-surgery approach. The preference could also change if survival were much more important to the patient in the first five years than after five years or if the patient disliked living on anticoagulants enough to value a year on anticoagulants as worth only 80% of a year not on anticoagulants.

CONCLUSION

This decision analysis provides quantitative support for the impression that patients similar to the case scenario do better with surgery timed at the onset of ventricular dysfunction than with surgery delayed until symptoms develop. It thus supports the practice of following these patients noninvasively in order to time surgery.

Left ventricular hypertrophy reversal with labetalol and propranolol: a prospective randomized, double-blind study

Hypertensive patients with left ventricular hypertrophy (LVH) have increased cardiovascular morbidity and mortality. Experimental studies indicate the importance of both the alpha and beta components of the adrenergic nervous system in the development and reversal of LVH. Therefore labetalol (L), a combined alpha and beta blocker, and propranolol (P), a nonselective beta blocker, were evaluated in a randomized, double-blind study of 35 hypertensive patients with echocardiographic evidence of LVH. Following 2 weeks of placebo, L or P was titrated as needed and tolerated to maximum total daily doses of 1600 mg and 640 mg, respectively. A thiazide diuretic was added if necessary for blood pressure control. M-mode echocardiograms were performed at baseline and after 1, 3, 6, and 12 months of blood pressure control. The echocardiograms were read independently by two blinded observers for end-diastolic dimension and wall thicknesses, and left ventricular mass. Fractional shortening, cardiac output, and peripheral vascular resistance were derived using standard formulas. Both drugs reduced blood pressure significantly and comparably. Significant changes in the echocardiographic measurements were observed as early as 1 month and usually persisted throughout the study. Both drugs decreased posterior wall thickness; however, only the decrease in propranolol group achieved statistical significance. Septal wall thickness was reduced by L at 3 and 12 months. End-diastolic dimension increased significantly in the L-treated group at 3, 6, and 12 months of therapy, whereas P had no effect on this measurement.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk reduction following regression of cardiac hypertrophy

Cardiac hypertrophy in essential hypertension is documented to be an independent risk factor for congestive heart failure, coronary heart disease and cardiac sudden death. Reduction of left ventricular hypertrophy therefore emerged as a new challenge of antihypertensive treatment. Sympatholytic agents, calcium entry blockers, and angiotensin converting enzyme inhibitors have been found to reduce left ventricular hypertrophy, whereas vasodilators (and most likely also diuretics) are unable to reduce left ventricular mass despite good control of arterial hypertension. Several studies indicated that reduction of left ventricular hypertrophy is not detrimental to cardiac pump function: systolic and diastolic function were found to be maintained at rest and during exposure to increased pressure load. In hypertensive patients with left ventricular hypertrophy ventricular arrhythmias have been reported to be increased and to be the pathophysiological link for the increased risk of cardiac sudden death. Reduction of cardiac hypertrophy was found to be accompanied by a reduction of prevalence and severity of ventricular arrhythmias if treated with betablockers, calcium entry blockers or converting enzyme inhibitors. Whether reduction of cardiac hypertrophy indeed decreases the cardiovascular risk attributed to left ventricular hypertrophy is unknown at present, although clinical studies support such a viewpoint.

Reversal of left ventricular dilatation, hypertrophy, and dysfunction by valve replacement in aortic regurgitation

Although aortic valve replacement for aortic regurgitation relieves left ventricular volume overload, ventricular geometry does not consistently normalize. To assess the extent, determinants, and functional consequences of reversal of left ventricular dilatation and hypertrophy, 38 patients with severe aortic regurgitation were studied pre- and postoperatively by serial echocardiography and radionuclide cineangiography. Left ventricular end-diastolic dimension normalized in 58% of patients by 9 +/- 6 months postoperatively, at which time 50% of patients had normalized mass; cumulative normalization rose to 66% for end-diastolic dimension and 68% for left ventricular mass during further follow-up. All patients who had normalized end-diastolic dimension also had normal postoperative ejection fractions (mean 61 +/- 8%). In contrast, patients in whom the left ventricle remained dilated had a 42% prevalence of subnormal postoperative left ventricular ejection fraction. Preoperative left ventricular end-systolic dimension less than or equal to 55 mm identified 86% of patients in whom end-diastolic dimension normalized, whereas end-systolic dimension exceeded 55 mm in 81% of those with persistent dilatation; other proposed preoperative predictors of operative outcome correctly identified lower proportions (from 59% to 71%) of patients in whom left ventricular size did or did not normalize. In conclusion, aortic valve replacement resulted in normalized left ventricular chamber size and mass in two thirds of the patients selected for operation by current criteria; favorable geometric outcome is associated with persistence or recovery of normal left ventricular function.

Hemodynamic progression of aortic stenosis in adults assessed by Doppler echocardiography

Doppler echocardiography was used to follow the hemodynamic severity of aortic stenosis. First, the reproducibility of repeat recordings (mean interval 28 +/- 36 days) of aortic jet velocity, made by two independent observers, was tested in 38 adults with aortic stenosis and unchanged clinical status. The two recordings of maximal velocity correlated well (r = 0.96, y = 0.88x + 0.46m/s, SEE = 0.21 m/s) with a mean coefficient of variation of 3.2%. Repeat recording of left ventricular outflow tract velocity by two independent observers in 10 other patients with aortic stenosis also correlated well (r = 0.94, y = 1.06x + 0.0 m/s, SEE = 0.06 m/s) with a mean coefficient of variation of 4.6%. Next, Doppler echocardiography was used to study 42 patients with aortic stenosis (mean age 66 years) over a follow-up interval of 6 to 43 months (mean 20). Maximal aortic jet velocity increased by 0.36 m/s per year (range -0.3 to +1.0 m/s per year). Mean transaortic pressure gradient changed by -7 to +23 (mean 8) mm Hg/year. Aortic valve area by the continuity equation (n = 25) decreased by 0 to 0.5 cm2/year (mean decrease 0.1 cm2/year). Some patients had a worsening of stenosis (decrease in valve area) even though they had no change or a decrease in pressure gradient, because of concurrent decreases in transaortic volume flow. Twenty-one patients (50%) developed new or progressive symptoms of aortic stenosis necessitating valve replacement.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of diltiazem on left ventricular mass and diastolic filling in mild to moderate hypertension

It is still uncertain whether antihypertensive therapy with calcium antagonists in general, and diltiazem in particular, can reduce left ventricular (LV) mass index and improve LV diastolic filling in hypertension. Therefore, 24 patients with mild to moderate hypertension (diastolic blood pressure 95 to 114 mm Hg before therapy) were randomly assigned to receive either a sustained-release preparation of diltiazem (n = 13) or placebo (n = 11) for 16 weeks in a double-blind, parallel-group protocol. M-mode and pulsed Doppler echocardiograms were performed at baseline and at the end of monotherapy. Echocardiograms were read blindly by 2 independent observers. The patients who received placebo exhibited no change in blood pressure, cardiac dimensions or LV function. Diltiazem significantly reduced both systolic pressure (151 +/- 14 to 139 +/- 12 mm Hg) and diastolic pressure (101 +/- 4 to 90 +/- 7 mm Hg, both p less than 0.05). Posterior wall and septal wall thicknesses decreased, but the changes were not statistically significant. End-diastolic dimension was reduced by diltiazem from 53 +/- 5 to 51 +/- 5 mm (p less than 0.05). LV mass index decreased significantly with diltiazem by 10%, from 125 +/- 21 to 113 +/- 23 g/m2 (p less than 0.05). The LV wall thickness to radius ratio remained unchanged during both diltiazem and placebo treatments. Changes in LV mass index and blood pressure did not correlate, suggesting that this response is influenced by factors other than pressure reduction alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term vasodilator therapy of chronic aortic insufficiency. A randomized double-blinded, placebo-controlled clinical trial

Although vasodilator drugs acutely reduce regurgitation and improve cardiac performance in aortic insufficiency, their long-term effects on left ventricular size and function are uncertain. Consequently, we performed a double-blinded, placebo-controlled trial using hydralazine in 80 minimally symptomatic patients who had clinically stable, moderate-to-severe aortic insufficiency. Patients randomized to hydralazine displayed a progressive reduction in left ventricular end-diastolic volume index (LVEDVI) measured by radionuclide angiography, the predetermined end point of the study. At 24 months, mean LVEDVI had been reduced by 30 +/- 38 ml/m2, an 18% reduction from baseline. In contrast, LVEDVI changed minimally in patients randomized to placebo, and the intergroup differences over time were statistically significant (p less than 0.03). The hydralazine group also experienced reductions in left ventricular end-systolic volume index and increases in ejection fraction that were significantly different (both p less than 0.01) from changes in placebo-treated patients. These findings show that long-term treatment with hydralazine reduces the volume overload in aortic insufficiency and suggest that such therapy may have a beneficial effect on the natural history of the disease.

Chronic aortic regurgitation: indications for operation--1988

Timing of operation in a patient with severe aortic regurgitation is a difficult and controversial decision, especially when the patient is asymptomatic or minimally symptomatic. A rational decision can be made when the pathophysiologic features of aortic regurgitation and the natural history of medically treated patients are understood and the benefits and risks associated with aortic valve replacement are known. Proper interpretation of the literature involving echocardiography and nuclear cardiology is essential, as is consideration of the constantly changing surgical techniques and results. Aortic valve replacement should be recommended for those patients with chronic aortic regurgitation who are severely symptomatic (New York Heart Association Functional Class III or IV), in order to ameliorate symptoms and increase longevity. In asymptomatic or minimally symptomatic patients, close continued serial follow-up is necessary in order to detect the onset of resting left ventricular dysfunction and to recommend the optimal timing for surgical intervention.

Reproducibility of rest and exercise left ventricular ejection fraction and volumes in chronic aortic regurgitation

To assess the variability of rest and exercise radionuclide ventriculography in patients with aortic regurgitation (AR), 22 patients in stable condition with chronic AR underwent radionuclide ventriculography at rest and during exercise for measurement of left ventricular volumes and ejection fraction (EF) on 2 occasions 3 months apart. For the group, there were no significant differences between the findings of the 2 studies except for a slightly lower exercise end-systolic volume on the second study. The inter-study differences and variabilities (expressed as the standard deviation of differences) for rest and exercise EF and change in EF were 0 +/- 0.04, +0.02 +/- 0.05 and +0.01 +/- 0.05, respectively. Thus, although mean differences were minor, considerable individual variability occurred, the magnitude of which was similar to that reported for other patient populations. In 3 patients who had an initial normal response to exercise (increase in EF greater than or equal to 0.05), the response became abnormal and in 2 who initially had an abnormal response, the response normalized. This variability must be considered in clinical decision-making or in research study design for patients with chronic AR.

Reproducibility of echocardiographic left ventricular measurements

Serial echocardiograms with acceptable reproducibility of measurements may be produced by careful performance and interpretation of the studies. The following recommendations have been shown to enhance reproducibility. Strict adherence to quality control is necessary to generate echocardiograms of the highest technical quality. Sonographers should be aware of the definition of a technically adequate study--including correct beam or plane angulation and continuous visualization of interfaces--and seek this ideal in every study. Participation by the sonographer in performance of measurements enhances recognition of the requirements for accurate quantitative echocardiography. Regular machine calibration is a prerequisite to accurate quantitative echocardiography. Considerable effort must be made to standardize the position of each acoustic window and angulation from which the patient is imaged--with deviation from these norms being recorded for future reference. If at all possible, measurements should be taken at end expiration. If that is not possible, measurement of several consecutive beats will limit the impact of respiratory variation. A uniform convention of measurement should be adopted. The best candidates for M-mode measurements are the American Society of Echocardiography recommendations for general measurement and the Penn convention for calculation of M-mode left ventricular mass. Further data is needed to determine which approaches to two-dimensional measurements best combine accuracy and reproducibility. Interpretation of echocardiograms may be made most reproducible by measuring pertinent parameters from multiple beats and using the mean as the result and by having at least two readers interpret each echocardiogram, possibly with two separate readings by each reader.