Background: Unexplained pulmonary hypertension is assumed to occur mainly in young adults.
Objectives: To describe the features of the disease in older patients and compare them to those in PHT patients of all ages.
Methods: We conducted a retrospective evaluation of the files of patients over 65 years of age in whom UPHT was diagnosed between 1987 and 1999 at two PHT centers serving a population of 4 million. Patients were followed for survival until March 2003. Clinical variables of the study patients were compared to those in PHT patients of all ages.
Results: The study group included 14 patients, 10 females and four males, with a mean age of 70.5 ± 6.7 years. The calculated mean annual incidence of UPHT for the study population was one new case per year per million persons. Seven patients (50%) had systemic hypertension. The mean interval from onset of symptoms to diagnosis was 8.3 months. At diagnosis, 64% of patients had functional capacity of III-IV according to the New York Heart Association classification, and 43% had right heart failure. Mean systolic pulmonary artery pressure was 80 ± 21 mmHg, peripheral vascular resistance 11.7 ± 7 mmHg/L/min, cardiac index 2.16 ± 0.81, and mean right atrial pressure 10.5 ± 5.9 mmHg. Median survival time was 43 months; survival rates for 1 year, 3 years and 5 years were 92.6%, 50%, 40%, respectively. Compared to data from the U.S. National Institute of Health Registry, UPHT in older patients is more common in females, but the incidence as well as clinical, hemodynamic and survival parameters are similar to those in PHT patients at any age.
Conclusions: UPHT occurs in the elderly more frequently than previously thought, with similar features in PHT patients of all ages. The coexistence of systemic and pulmonary hypertension warrants further investigation.