Diffusion capacity and haemodynamics in primary and chronic thromboembolic pulmonary hypertension

Abstract

The transfer factor of the lung for carbon monoxide (TL,CO) is decreased in patients with pulmonary hypertension. The pulmonary membrane diffusion capacity (Dm) and pulmonary capillary blood volume (Vc), were studied to establish: 1) the relative contribution of the components of the transfer factor to the decrease in TL,CO; 2) whether differences exist between primary pulmonary hypertension (PPH) and chronic thromboembolic pulmonary hypertension (CTEPH); and 3) the relationship between these parameters and haemodynamic parameters.Dm and Vc were determined in 19 patients with PPH and in eight patients with CTEPH. The patients had been referred for consideration for lung transplantation. Haemodynamic parameters were assessed by heart catheterization.In the PPH group, Vc was reduced in 12 of 19 patients (mean SD Vc 72 14% of the predicted value) and Dm in 17 of 19 patients (60 22% pred). In the CTEPH group, Vc was reduced in six of eight patients and Dm in seven of eight patients. The mean TL,CO Dm and Vc values were similar to those in the PPH group.The reduction in pulmonary membrane diffusion capacity was significantly greater than that in pulmonary capillary blood volume. No differences in pulmonary and cardiovascular functional values were found between the groups. Right atrial pressure showed a significant negative correlation with pulmonary capillary blood volume and an increased pulmonary vascular resistance was associated with a decrease in pulmonary membrane diffusion capacity. These results suggest pronounced functional impairment of the alveolocapillary membrane in these patients. Eur Respir J 2000; 16: 276±281.

Impairment of pulmonary function and changes in the right cardiac structure of pneumoconiotic coal workers in China

“…Pulmonary vascular remodeling resulted in PASP, inducing changes to the right cardiac structure. Abbreviations as in Tables 1-3. causes poor alveolar perfusion [15,16]. Our findings were in agreement with Wang's study revealing that the miners with coal workers' pneumoconiosis had lower values of pulmonary function and higher prevalence of respiratory symptoms than did those without it, and a significant relationship was found between coal workers' pneumoconiosis and decrements in FVC and diffusing capacity.…”

Prognostic and aetiological factors in chronic thromboembolic pulmonary hypertension

“…It is therefore possible that the increased perioperative mortality observed by the present authors in patients with lower TL,CO was due to a higher degree of distal vasculopathy. STEENHUIS et al [15] were, however, unable to demonstrate a difference in DM or Vc in patients with idiopathic pulmonary arterial hypertension and CTEPH [15]. Furthermore, there was no significant difference in the TL,CO of patients in the present study with either operable or nonoperable disease (69.1 versus 68.4%; p50.72) [2].…”

Effects of Balloon Pulmonary Angioplasty on Oxygenation in Patients With Chronic Thromboembolic Pulmonary Hypertension – Importance of Intrapulmonary Shunt –

“…9,10,25 Because CTEPH is less associated with ventilation abnormalities, there should be no unventilated alveoli. 27 Indeed, in the present study, lung function tests and computed tomography of the lung showed no evidence of respiratory disease. Thus, intrapulmonary shunt, such as preexisting arterial-venous anastomoses and low ventilationperfusion units, is likely involved.…”