Even Mild LVD Raises Ischemic Stroke Risk

Caroline Cassels

June 02, 2006

June 2, 2006 — Mild left ventricular dysfunction (LVD) raises the risk for ischemic stroke as much as moderate to severe reductions in ejection fraction, a new study suggests.

Conducted by researchers at New York University and Columbia University Medical Center in New York City, the study found patients with any degree of LVD had a 4-fold increased risk for ischemic stroke compared with matched controls. In those with mild LVD, the magnitude of the risk for ischemic stroke was still more than 3.5 times greater.

"The magnitude of stroke risk associated with mild left ventricular dysfunction, which in many cases is asymptomatic, was quite impressive. Based on these results, I think assessment of stroke risk, which includes consideration of classic risk factors such as hypertension, diabetes, and smoking, should also include mild LVD," senior author Marco Di Tullio, MD, told Medscape.

The lead investigator of the study, which was published online June 1 in Stroke, is Allison Hays, MD, from the Department of Medicine at New York University in New York City.

Previous studies, including an analysis from the Study of Left Ventricular Dysfunction (SOLVD) and the Survival and Ventricular Enlargement (SAVE) trial, have established a link between heart failure and increased stroke risk primarily among patients with previous myocardial infarction, the researchers point out.

"The literature shows an increased risk of stroke in people who have cardiac disease, especially among those surviving myocardial infarction. But not much is known about the association between LVD — particularly mild or asymptomatic LVD — and stroke risk in the general population," Dr. Di Tullio said.

This case control study assessed the role of LVD as an independent risk factor for ischemic stroke in the multiethnic population of the Northern Manhattan Study (NOMAS).

A total of 270 patients with first-time ischemic stroke and 288 age-, sex-, and race-matched community controls were included in the analysis.

Control subjects were eligible to participate if they had no prior diagnosis of stroke, were older than 39 years, and had lived in northern Manhattan for more than 3 months. Transthoracic echocardiography was performed in all subjects within 3 days of stroke onset in stroke patients and on enrollment in control subjects.

LVD was diagnosed in 24.1% of stroke patients and 4.9% of controls. Regardless of its severity, LVD was significantly more common in stroke patients than in controls. Moderate to severe LVD was present in 13.3% of stroke patients vs 2.4% of controls, and mild LVD was detected in 10.7% of stroke patients vs 2.4% of controls.

After researchers controlled for other risk factors, including hypertension, atrial fibrillation, and smoking status, LVD remained a statistically significant predictor of increased stroke risk and had a significant effect across the entire spectrum of patients.

Adjusted Risk for Ischemic Stroke Associated With Degrees of LVD

LVD Degree
Odds Ratio
95% Confidence Interval
Mild
3.96
1.56 – 10.0
Moderate/severe
3.88
1.45 – 10.39

According to the study, LVD of any degree increased the risk for stroke more than 3-fold in men and almost 5-fold in women. Patients younger than 70 years and olders than 70 years with LVD had a 3- and 5-fold increased risk, respectively.

Radical Change Warranted?

At this point, said Dr. Di Tullio, the implications for clinical practice are not entirely clear. Because mild LVD is often asymptomatic, widespread screening, in the absence of other predisposing conditions such as hypertension or advanced age, may not be warranted.

Furthermore, Dr. Di Tullio said, even if mild LVD were detected, it is not yet clear how it should be managed. Although there is some preliminary evidence that angiotensin-converting enzyme (ACE) inhibitors may delay the onset of clinically evident heart failure, at this point there is no evidence to suggest they or any other medications are effective in reducing stroke in patients with mild LVD.

Nevertheless, Dr. Di Tullio said, the study's findings do warrant a radical change in the way practicing physicians view LVD and its relationship to stroke risk. "At this point we shouldn't necessarily act on these findings, but I definitely think that left ventricular dysfunction should be considered as a potential risk factor for stroke," he said.

A prospective follow-up study, involving more than 1500 stroke-free subjects with baseline echocardiograms, is currently under way. Subjects are being followed over time to determine whether LVD at baseline confers increased stroke risk and the actual stroke risk per year for different levels of LVD severity. Results of the study are expected sometime in 2007.

Stroke. Published online June 1, 2006. Available at: http://stroke.ahajournals.org .

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