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Pulmonary hypertension often goes undiagnosed in patients with scleroderma and mixed connective tissue disease despite being a major complication and leading cause of death, according to a study reported October 17 at the American College of Rheumatology annual meeting in San Antonio.
Another study presented at the same meeting found that the experimental drug sitaxsentan for pulmonary hypertension may improve the quality of life for such patients.
Scleroderma and mixed connective tissue disease are two types of rheumatic autoimmune diseases that cause inflammation, damage and scarring in the skin and internal organs, including the lung and its blood vessels. Pulmonary hypertension (high blood pressure in the lungs) is a common and devastating complication of these diseases, resulting in death in half the cases within two to three years after diagnosis.
However, the onset of pulmonary hypertension may be without signs and symptoms, like tiredness or shortness of breath. Therefore, diagnosis is often difficult and very little information exists on the prevalence of pulmonary hypertension in patients followed in community practice, according to the study.
To assess the prevalence of pulmonary hypertension in people with scleroderma and mixed connective tissue disease, researchers studied 669 patients who had no previous diagnosis of pulmonary hypertension. Patients underwent a Doppler echocardiogram of the heart and exercise tolerance questioning.
Pulmonary hypertension was considered present if the echocardiogram showed an estimated right ventricular systolic pressure of greater than 40mmHg. Eighty-nine or 13.3 percent of the participants were deemed to have pulmonary hypertension.
According to researchers, this significant number of pulmonary hypertension cases suggests that an echocardiogram evaluation of patients with scleroderma or mixed connective tissue disease should be conducted regularly. Only a minority of these patients had ever had a workup to look for pulmonary hypertension.
"Pulmonary hypertension is a silent killer of these patients, difficult to detect by simple bedside examination until the late irreversible stage is present," said researcher Fredrick Wigley, MD, of Johns Hopkins University in Baltimore. "Patients should be screened regularly because early detection with (echocardiogram) technology provides the opportunity to treat with new available vasoactive medications that potentially can prevent progression to severe life-threatening disease."
In the second study, researchers studied whether sitaxsentan, a once-daily oral endothelin receptor antagonist that blocks the action of endothelin on blood vessels, could improve the ability of pulmonary hypertension patients to exercise without difficulty.
The study involved 178 patients with pulmonary hypertension, including 42 with pulmonary hypertension related to a connective tissue disease. Patients received either 100 milligrams or 300 milligrams of sitaxsentan or a placebo for 12 weeks.
All patients participated in a six-minute walk test before the treatment began and again at the end of the study. Those with pulmonary hypertension related to connective tissue disease taking either dosage of sitaxsentan significantly improved their walking distance as compared to those taking placebo. The time of those taking a placebo actually worsened.
Sitaxsentan was also shown to significantly improve the cardiac index and pulmonary vascular resistance of patients with pulmonary hypertension related to connective tissue disease.
Lead researcher Vallerie McLaughlin, MD, University of Michigan Hospital, said once-daily oral therapy with sitaxsentan sodium appears to represent an important treatment advance since an existing therapy, epoprostenol, is often difficult for patients to tolerate as it requires a central catheter and continuous intravenous infusion.
Source:
Medical Week staff,
week of October 23, 2004
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