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Prognosis

Echocardiographic left ventricular hypertrophy predicted mortality and cardiovascular events in hypertension

ACP J Club. 1991 Jul-Aug;115:26. doi:10.7326/ACPJC-1991-115-1-026


Source Citation

Koren MJ, Devereux RB, Casale PN, Savage DD, Laragh JH. Relation of left ventricular mass and geometry to morbidity and mortality in uncomplicated essential hypertension. Ann Intern Med. 1991 Mar 1;114:345-52.


Abstract

Objective

To investigate the prognostic value of left ventricular (LV) hypertrophy measured by echocardiography in patients with essential hypertension.

Design

A cohort study with follow-up of 7 to 12 years.

Setting

A hospital in New York, USA.

Patients

Patients were referred for hypertension research studies, including echocardiography, between 1976 and 1981. Patients with essential hypertension were followed for hypertensive complications through telephone interviews, which were corroborated by physicians and records, if possible. 412 consecutively referred patients with hypertension were evaluated. Patients with secondary hypertension, pre-existing cardiac disease, or pre-existing illnesses that affect longevity were excluded. 280 patients were eligible and 27 of these were lost to follow-up.

Assessment of prognostic factors

Baseline echocardiograms were evaluated blinded to clinical information. LV mass index was calculated by dividing ventricular mass by body surface area; 125 g/m2 corresponding to the 95th percentile of normal ventricular mass in men, was chosen as the cut-off point for both men and women. Age, sex, smoking habits, recent clinic blood pressure, and serum cholesterol levels were recorded.

Main outcome measures

All-cause mortality (confirmed through the National Death Index), cardiovascular deaths, and nonfatal cardiovascular events (new angina, myocardial infarction, coronary bypass or angioplasty, congestive heart failure, stroke, and carotid endarterectomy).

Main results

LV mass index was increased in 77 of 280 patients (28%). 8 deaths (4%) occurred among patients with normal LV mass and 11deaths (14%) occurred among patients with increased LV mass (P = 0.002). More cardiovascular deaths also occurred among the patients with LV hypertrophy, 10 (14%) compared with 1 (1%) (P < 0.001). 18 patients (26%) with left ventricular hypertrophy had at least 1 cardiovascular event compared with 22 patients (12%) without hypertrophy (P = 0.006). LV hypertrophy on electrocardiography was weakly related to cardiovascular events. In step-wise logistic regression analyses, only age and LV mass index were independent predictors of death or cardiovascular death or events P ≤ 0.01 for all comparisons. Concentric LV hypertrophy carried a worse prognosis than eccentric hypertrophy, concentric remodeling, or normal geometry.

Conclusion

Echocardiographic left ventricular hypertrophy in patients with essential hypertension was predictive of mortality and cardiovascular events.

Source of funding: In part, National Heart, Lung, and Blood Institute.

Address for article reprint: Dr. R.B. Devereux, Division of Cardiology, Box 222, The New York Hospital-Cornell Medical Center, 525 East 68th Street, New York, NY 10021, USA.


Commentary

This study provides further evidence that echocardiographically measured LV mass predicts adverse outcomes from hypertension. Age and echocardiographic LV hypertrophy independently predicted subsequent cardiovascular events.

There were limitations to the study design and execution that may have influenced the results. First, the patients' age range was wide, and the duration of hypertension at entry was variable, producing a rather diverse cohort. Second, the cohort consisted of volunteers for research studies and may not be representative of general populations. Third, patient and physician reporting of morbidity and causes of death may have been influenced by the knowledge of echocardiographic abnormalities. Fourth, the collection of outcome data was not preplanned and it is not stated how much of the telephone data was backed up by documentation from records.

Does echocardiography add prognostic information to that provided by readily available and less expensive diagnostic methods? LV mass reflects systolic blood pressure, so either of these 2 highly correlated variables may effectively substitute for the other. In the step-wise logistic analysis in this study, where LV mass was included first, systolic blood pressure no longer appeared to provide "independent" information; the clinically important question about the added value of echocardiography could have been answered by "forcing in" these standard items. Nevertheless, the regression analyses do establish that age and LV mass are the strongest independent predictors of morbidity from hypertension.

Richard A. Reeves, MD
University of TorontoToronto, Ontario, Canada


Author's Response

We were able to corroborate the reports of patients and family members with death certificates, doctors' reports, or hospital records for 33 of 40 patients with events. "Forcing in" systolic blood pressure, diastolic blood pressure, gender, or cholesterol did not change the independent predictive value of LV mass.

Michael J. Koren, MD