PURPOSE: Pulmonary arterial hypertension (PAH) is a group of diseases characterized by an impressive increase in pulmonary vascular resistances (PVR) that causes severe right ventricular (RV) dysfunction. The prognosis is related to the severity of hemodynamic impairment. Because the pathophysiologic model is an afterload mismatch we hypotisize that the best RV adaption should be a “concentric” hypertrophy (i.e. high RV mass/volume ratio).
METHODS: We evaluated 49 consecutive patients with PAH (42 idiopathic, 7 associated to SSc) who underwent clinical (NYHA class) effort capacity (6MWT) hemodynamic and MR imaging evaluation as routine work-up at the time of diagnosis. Population was divided in two groups on the basis of median value of RV mass/diastolic volume ratio (Gr1 RV M/V< 0.62, Gr2 RV M/V>0.62) and followed-up for deaths (average of 2.3+1.2 years).
RESULTS: Patients with higher RV M/V ratio have lower RV systolic (Gr1 118+65 Gr2 77+25 ml;p=0,006) and diastolic volume (Gr1 171+63, Gr2 121+26 ml;p< 0,005) but similar RV mass (Gr1 88+28, Gr2 92+20 gr;p=ns ) compared to patients with RV M/V ratio below the median. Moreover, despite no significant differences in clinical status (NYHA class Gr1 2,3+0,5, Gr2 2,3+0,6;p=ns), effort capacity (6MWT, Gr1 400+116, Gr2 427+126;p=ns) and hemodynamics (RAP, mmHg Gr1 8+4, Gr2 6+3; p=ns; PAPm, mmHg Gr1 55+18, Gr2 48+10;p=ns. CI l/min/m2 Gr1 2,2+0,8, Gr2 2,4+0,7:p=ns, PVR, mmHg/l Gr1 13+9,8 Gr2 10,7+5,4;p=ns) between the two groups, Gr2 patients have a lower mortality (deaths Gr1 5/24, Gr2 1/25; p=0,007).
CONCLUSION: In PAH it is possible to identify patients with RV hypertrophy and mild diastolic volume increase (i.e. high mass/volume ratio) which has a low rate of deaths, suggesting a favorable prognostic role of this parameter. The low rate of events (deaths) in this preliminary study does not allow a Cox proportional hazard analysis, thus these results should be confirmed in a larger population.
CLINICAL IMPLICATIONS: The type of RV remodelling (concentric vs eccentric hypertrophy) could be the expression of adequacy of adaptation in PAH, and have significant prognostic impact.
DISCLOSURE: Carmine Dario Vizza, No Financial Disclosure Information; No Product/Research Disclosure Information