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Hypertension & LVH
Hypertension and Left Ventricular Geometry in the HOT trial
The Hypertension Optimal Treatment (HOT) trial randomised over eighteen thousand hypertensive patients, with a mean age of just over 61 years, and with diastolic blood pressures between 100 and 115 mmHg to three different strategies. The trial was designed to try to determine if it was possible to show a difference in outcome if the target diastolic pressure was less than 90mmHg vs 85mmHg vs 80mmHg.
A sub-study assessed the impact of treatment on echo assessment of left ventricular hypertrophy. An oral presentation at the NZ Regional Meeting of the Cardiac Society of Australia and New Zealand in 1999 described some of the findings.
Sixty percent of patients did not have left ventricular hypertrophy (LVH) at entry into the study. However, of those without LVH more than two thirds had concentric LV remodelling. The distribution of the geometric patterns is shown in the graphic below.
At the end of the study the proportion of patients without LVH had increased to only 72%, despite reduction of diastolic pressures of 20-24 mmHg in the overall study.
I do not know if we can expect to normalise LV mass with very good control of hypertension in an even higher percentage of patients than demonstrated in this study. One might wonder if a longer period of optimal control of hypertension is required to reverse these changes in an even greater proportion of patients. It is not certain that we should modify our treatment of hypertension simply based on assessment of LV mass by performing regular repeat echo examinations- ensuring good control of office or ambulatory blood pressure should remain the primary goal.
I suspect a single assessment for LVH with echocardiography may be valuable in some patients.
- Echo may help in confirming the need to initiate treatment for hypertension or emphasising the need to ensure good control of hypertension. This might particularly apply to patients that do not exceed the "treatment threshold" recommended by the NZ guidelines on prevention of cardiovascular disease. In other words, even though a particular patient may have a risk below the treatment threshold, we might decide that echo evidence of LVH should not be ignored and anti-hypertensive treatment started.
- There will be other patients in whom we may decide to try to ensure "optimal control of hypertension" rather than just try to reduce the calculated risk below 15% as recommended by the NZ guidelines.
Hitesh Patel, Cardiologist
5th August, 2004