Reliability and limitations of echocardiographic measurement of left ventricular mass for risk stratification and follow-up in single patients: the RES trial. Working Group on Heart and Hypertension of the Italian Society of Hypertension. Reliability of M-mode Echocardiographic Studies.
OBJECTIVE
To investigate the clinical reliability of repeated measurements of left ventricular mass in a single patient.


METHODS
We used test-retest reliability analysis, within-class correlation and interval of agreement measures.


METHODS
Two M-mode tracings (three consecutive cycles) were recorded in the same session and 3-10 days apart (5+/-2 days; mean +/- SD) in 261 participants (age 45+/-13 years, body mass index 24.7+/-3.6 kg/m2; 131 hypertensive and 130 normotensive; 50% of each group women) in 16 centres in Italy. The two tracings were read by two observers in each centre, after classification by a three-order quality score (1 = poor, 2 = sufficient, 3 = optimal).


RESULTS
The average quality score was 2.11+/-0.71 (21% poor, 50% sufficient, 29% optimal). Left ventricular mass values ranged from 56 to 419 g (170+/-61 g). On the same day, within-observer 90% interval of agreement between tracing 1 and tracing 2 was -28 to +22 g (-17 to +11% of tracing 1). For day-to-day test-retest within-observer variability (average three cycles), the 90% interval of agreement was -30 to +35 g (-18 to +18%). This variability decreased to -13 to +12% at the 80% interval of agreement and -12 to +11% at the 75% interval of agreement. The 90% interval of agreement of test- retest between-observer variability was -26 to 30 g (-19 to +15%). A negligible regression toward the mean was identified. Categorical consistency of retest in the identification of hypertensive patients with left ventricular hypertrophy, classified in the first study, was 87% (k = 0.87).


CONCLUSIONS
Measurement of left ventricular mass in single patients allows reliable risk stratification on the basis of the presence of left ventricular hypertrophy. The probability of a true change in left ventricular mass over time is maximized for a single-reader difference greater than 18% of the initial value, although differences of 10-13% might also have clinical relevance.
de Simone
G
G
Department of Clinical and Experimental Hypertension, Federico II University Hospital, Naples, Italy. simogi@unina.it
Muiesan
M L
ML
Ganau
A
A
Longhini
C
C
Verdecchia
P
P
Palmieri
V
V
Agabiti-Rosei
E
E
Mancia
G
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004452:Echocardiography / Q000592:standards*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012307:Risk Factors