Disfunção Diastólica - by theheart

LV diastolic dysfunction, even in healthy people, linked to heart failure

Rochester, MN - Signs of left ventricular diastolic dysfunction that may eventually lead to heart failure can be detected even in healthy patients, new data from the Olmsted County Heart Function Study show [1].

This study "documents that, with the passage of time, there is a tendency for diastolic dysfunction in middle-aged and older people to worsen. That occurs not only in people who have risk factors for heart failure . . . but also in people who have no evidence for any sort of underlying cardiovascular disease," study coauthor Dr Richard Rodeheffer (Mayo Clinic, Rochester, MN) told heartwire. "It supports the general idea that the aging process just all by itself is probably associated with some deterioration of diastolic function of the left ventricle, and then if you add onto that problems like hypertension, cardiovascular disease, diabetes, and obesity, the probability of developing heart failure with preserved ejection fraction goes up quite substantially as people get older."

The National Institutes of Health-sponsored study, led by Dr Garvan Kane (Mayo Clinic), examined 2042 patients 45 years or older with echocardiography and clinical examination between 1997 and 2000 and graded their diastolic left ventricular function, from normal to severely dysfunctional, by validated Doppler techniques. The researchers reexamined study participants four years later, and they were then followed through 2010 for ascertainment of new-onset heart failure. A total of 1402 of the 1960 surviving patients came in for the second evaluation.

Between the first exam and the four-year follow-up exam, the prevalence of diastolic dysfunction in the study group increased from 23.8% to 39.2% (p<0.001). Nearly a quarter of study participants' diastolic function grade worsened during this period, while it improved in about 9% and stayed the same in just over two-thirds of the participants.

Worsened diastolic dysfunction was associated with age 65 years or older (odds ratio 2.85), and after a mean of 6.3 years of additional follow-up, 12.2% of patients whose LV diastolic dysfunction was moderate to severe developed heart failure. By contrast, during the follow-up period, only 2.6% of people with normal diastolic dysfunction showed heart failure, and 7.8% of participants with mild diastolic dysfunction developed heart failure (p<.001). The study also showed that diastolic dysfunction was associated with incident heart failure after adjustment for age, hypertension, diabetes, and coronary artery disease (hazard ratio 1.81).

"We have known for some time that hypertension and cardiovascular disease and diabetes all predispose one to the development of heart failure with preserved ejection fraction, and it's been presumed that part of the reason that those risk factors contributed to the development of heart failure with preserved ejection fraction had something to do with diastolic dysfunction, but nobody had ever really made measurements to show that that was the case," Rodeheffer said.

This study adds a longitudinal "change-within-individual" dimension to a previous analysis of the Olmsted study that provided cross-sectional estimates of left ventricular dysfunction prevalence in the community and described the relationship between ventricular dysfunction and clinical status, Kane and colleagues explain."This age-related progression of diastolic dysfunction in the population contributes to the pathophysiologic substrate from which overt heart failure emerges, [but] the biological pathways leading to heart failure with preserved LVEF are manifold, and understanding its pathophysiology remains a work in progress," Kane et al explain. Contributing factors may include changes in the myocardial relaxation and elastic recoil, ventricular load and diastolic stiffness, external constraint, or abnormal systolic function; the loss of peripheral vascular elasticity with age may affect ventricular load and stiffness, the authors point out.