Pulmonary haemodynamic and respiratory mechanics in patients with chronic heart failure

Introduction: Abnormalities in respiratory muscle function and central haemodinamic have been described in chronic heart failure (CHF) patients (pts). Purpose: We evaluated the relationship between pulmonary haemodinamic and respiratory mechanics in these pts. Methods: Seventeen CHF pts (age 62+10; 6 in II, 8 in III, 2 in IV NYHA class) underwent right heart catheterization and simultaneous assessment of respiratory mechanics: PAPtm=pulmonary arterial trasmural pressure, Pwdtm=wedge transmural pressure, occlusion pressure=PO.1, dynamic compliance=CLdyn, pressure time product inspiratory muscles=PTP, max inspiration pressure=MIP, breathing work=WOB, pressure time index=PTI, were assessed at rest and during maximal incremental bycicle exercise test. Results: As expected pts showed, at exercise peak, a significant increase in PWdtm (30±2.5→56±2.5), PAPtm (41±3→72±2), PO.1 (1.1±0.8→3.5±2.1), PTP (164±86→470±134), CLdyn (134±73→97±55), MIP (58±17→44±20), PTI (0.07±0.05→0.2±0.1), WOB (0.7±0.3→2±.08). The relationship between haemodynamic and mechanic parameters are reported in the table. Finally, CLdyn and MIP were significantly related to VO2 peak (r=0.48, p<0.05; r=0.67, p<0.004 respectively). PWdtm PAPtm r p< r p< PO.1 0.52 0.05 0.50 0.03 PTP 0.60 0.01 0.61 0.01 CLdyn -0.42 ns -0.38 ns MIP -0.64 0.001 -0.59 0.01 PTI 0.70 0.002 0.69 0.003 WOB 0.56 0.02 0.56 0.02 Conclusions: These preliminary data show that in CHF pts baseline haemodynamic parameters are heavly influenced by respiratory mechanic. This seems to be related with functional capacity in this pts. Clinical implications: This impairment in respiratory mechanic could contribute to explain the exercise limitation in CHF pts.