[Prognosis of primary pulmonary hypertension and its determinants]

Most patients with primary pulmonary hypertension (PPH) die within two to four years of the onsets of their symptoms. However, several reports have described patients with PPH who have lived more than 10 years including a case with regression. We studied prognoses and the various determinants in 21 patients (7 men and 14 women; 18 deceased and three living) with PPH to elucidate its pathophysiology. Age at the onset of the disease varied from 12 to 73 years, with a mean of 29 years. All causes of death were of right heart failure, except for two cases of non-cardiac deaths. The prognoses were as follows: less than one year, two cases; 1-2 years, seven (one living); 2-3 years, five; 3-4 years, two; 4-5 years, one; more than six years, four (two living), with a mean of three years and five months. Pulmonary artery pressure decreased 10 years later (mean pressure, from 54 to 41 mmHg) in one patient, who lived for 13 years, followed by a non-cardiac death. Various clinical and pathological factors, including age at the onset of disease, sex, relationship to pregnancy, immunological abnormalities (4, positive; 17, negative), patent foramen ovale (five, patent; 16, not patent), PaO2, hemodynamic parameters, treatments, pathological subtypes (10, plexogenic pulmonary arteriopathy; two, pulmonary micro-thromboembolism; one, pulmonary veno-occlusive disease) numbers of plexiform lesion/cm2 were examined for prognostic correlations. None of the above factors were found to correlate significantly with prognoses. The only significant correlation was between the cardiac index (r = 0.981, p less than 0.001, n = 6), and total pulmonary resistance (r = -0.894, p less than 0.02, n = 6) in patients with pregnancy-related PPH. There was variability in the state of progression, namely, from rapid progression to regression. Clinically as well as pathologically, PPH may consist of several subgroups. However, whether it is due to differences in etiology or reactions of the disease is not clear. The pregnancy-related cases may comprise a homogenous subgroup within PPH.