CHICAGO — Tissue Doppler imaging of the heart may be a way to safely and noninvasively screen asymptomatic people who are at risk of dying from heart failure, according to results from an initial study with 1,100 people.
In this pilot study, people in the lowest tertile of left ventricular motion had a 2.6-fold increased risk of dying over the next 5 years, compared with patients with the highest level of ventricular wall motion, in an analysis that controlled for age and gender, Dr. Rasmus Mogelvang said at the annual meeting of the American College of Cardiology.
Although the finding suggested that tissue Doppler imaging (TDI) may be effective for the early detection of heart failure and an increased risk of death due to heart failure, the data collected so far are preliminary and did not allow Dr. Mogelvang and his associates to calculate a threshold value for increased risk.
“This is a first step toward showing that TDI has promising significance,” said Dr. Mogelvang, a cardiologist at Gentofte Hospital in Copenhagen. “Before we can start to use this in daily practice, we need to set cutoff values.”
TDI can “clearly measure systolic and diastolic function in the heart. Putting them together [as a single measure of ventricular performance] is novel,” commented Dr. Scott D. Solomon, director of noninvasive cardiology at Brigham and Women's Hospital in Boston, and an expert on TDI. “If the results [from Dr. Mogelvang's study] are validated in another dataset, then TDI could become an important screening test,” he said.
Dr. Mogelvang and his associates used TDI data collected on 1,100 apparently healthy people (average age, 60 years) enrolled in the Copenhagen City Heart Study. They all underwent ventricular assessment using both TDI and conventional echocardiography, and were then followed for an average of 5.1 years. During follow-up, 90 people died.
Three TDI measurements were made for each subject: s', which corresponds to left ventricular wall motion at peak systole; e', which is wall motion between systole and diastole; and a', wall speed at end diastole. People with slower ventricular wall motion had worse survival. Older people have reduced wall-motion speed.
In a series of multivariate analyses that adjusted for baseline differences in age and gender, a combined wall-speed assessment that included readings for s', e', and a' was the best correlate of survival, Dr. Mogelvang reported. In absolute terms, 5-year survival was about 96% among people in the tertile with the greatest wall motion, about 92% among those in the middle tertile, and about 85% among those in the tertile with the lowest level of wall motion. The combined TDI value, which integrated s', e', and a', was a powerful predictor of survival even in people who had normal ventricular function based on their conventional echocardiogram, he said.