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Prediction of mortality risk by different methods of indexation for left ventricular mass
Y Liao1, R S Cooper, R Durazo-Arvizu
1Department of Preventive Medicine and Epidemiology, Loyola University Medical Center, Maywood, Illinois 60153, USA. YLIAO@LUCCPUA.IT.LUC.EDU
Insights
Left ventricular hypertrophy, regardless of how left ventricular mass is indexed to body size, predicts increased mortality risk. Different indexing methods for left ventricular mass show similar predictive value for all-cause and cardiac death.
Area of Science:
- Cardiology
- Clinical Medicine
- Diagnostic Imaging
Background:
- Discrepancies exist in optimal methods for indexing left ventricular mass to body size in clinical practice.
- Accurate assessment of left ventricular hypertrophy is crucial for risk stratification.
Purpose of the Study:
- To compare the predictive value of echocardiographically determined left ventricular hypertrophy on mortality.
- To evaluate various methods of indexing left ventricular mass for body size.
Main Methods:
- 988 patients with coronary angiograms and echocardiograms were followed for 7 years.
- Left ventricular mass was indexed using height, height squared, body surface area, and other metrics.
- Outcomes assessed included all-cause and cardiac mortality.
Main Results:
- Various left ventricular mass indexes were highly correlated (r=0.90-0.99).
- Increased left ventricular mass index was associated with similar risks of all-cause and cardiac death.
- Concordantly defined hypertrophy by body surface area and height indexes showed the highest risk.
Conclusions:
- Different methods for indexing left ventricular mass to body size show similar predictive value for mortality.
- Left ventricular hypertrophy, irrespective of the indexing method, confers an increased risk of death.
- This finding holds true for patients with and without coronary artery disease.
Objectives:
We sought to compare the predictive value of echocardiographically determined left ventricular hypertrophy on death from all causes and cardiac mortality using various methods of indexation for left ventricular mass.
Background:
Considerable controversy exists regarding the optimal method for indexing left ventricular mass to body size in the clinical setting.
Methods:
The study included 988 consecutive patients who had both coronary angiograms and echocardiographic examinations in an inner-city public hospital in Chicago, Illinois. Patients were followed up for a mean of 7 years (range 2 to 11).
Results:
Various left ventricular mass indexes (e.g., mass indexed for height, height2, height2.13, height2.7, body surface area and body surface area1.5 were highly correlated (r = 0.90 to 0.99). Used as a continuous measure, an increase in any left ventricular mass index was associated with similar risk of death from all causes and cardiac diseases. Although left ventricular hypertrophy assessed by mass indexed for body surface area using the published conventional partition values provided somewhat better prediction, the adjusted relative risk was in general not significantly different from hypertrophy based on other indexes. Patients with left ventricular hypertrophy defined concordantly by indexes based on both body surface area and height (or height2.7) had, by definition, the highest average mass indexes among all groups and experienced as much as a threefold greater risk of death than those without hypertrophy. A small proportion of patients (12%) who were classified into the hypertrophy group by height-based indexes alone, but not by body surface area, had a moderate increase in mass and showed no increase in risk, even though being overweight was extremely prevalent in this group.
Conclusions:
Because of the high correlation among various body size indexes, left ventricular hypertrophy, defined by different indexes for left ventricular mass, similarly confers increased risk of mortality in patients with or without coronary artery disease.