Pulmonary vascular resistance and compliance stay inversely related during treatment of pulmonary hypertension.
OBJECTIVE
Pulmonary arterial compliance (C) is increasingly being recognized as an important contributor to right ventricular afterload, but for monitoring of treatment of pulmonary hypertension (PH) most often still only pulmonary vascular resistance (R) is used. We aimed at testing the hypothesis that R and C are coupled during treatment of PH and that substantial changes in both R and C would result in more haemodynamic improvement than changes in R alone.


RESULTS
Data were analysed of two right-heart catheterizations of 52 patients with pulmonary arterial hypertension and 10 with chronic-thromboembolic PH. The product of R and C (= stroke volume over pulse pressure) did not change during therapy (P = 0.320), implying an inverse relationship. Changes in cardiac index correlated significantly (P < 0.001) with changes in R (R(2) = 0.37), better with changes in C (R(2) = 0.66), and best with changes in both (R(2) = 0.74).


CONCLUSIONS
During therapy for PH, R and C remain inversely related. Therefore, changes in both R and C better explain changes in cardiac index than either of them alone. Not only resistance but also compliance plays a prominent role in PH especially in an early stage of the disease.
Lankhaar
Jan-Willem
JW
Department of Physics and Medical Technology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands.
Westerhof
Nico
N
Faes
Theo J C
TJ
Gan
C Tji-Joong
CT
Marques
Koen M
KM
Boonstra
Anco
A
van den Berg
Fred G
FG
Postmus
Pieter E
PE
Vonk-Noordegraaf
Anton
A
D000328:Adult; D000368:Aged; D006328:Cardiac Catheterization; D002317:Cardiovascular Agents / Q000627:therapeutic use*; D003187:Compliance; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000188:drug therapy* / Q000503:physiopathology; D014655:Vascular Resistance / Q000502:physiology
D002317:Cardiovascular Agents