title: Pulmonary transit of agitated contrast is associated with enhanced pulmonary vascular reserve and right ventricular function during exercise.
abstract: Pulmonary transit of agitated contrast (PTAC) occurs to variable extents during exercise. We tested the hypothesis that the onset of PTAC signifies flow through larger-caliber vessels, resulting in improved pulmonary vascular reserve during exercise. Forty athletes and fifteen nonathletes performed maximal exercise with continuous echocardiographic Doppler measures [cardiac output (CO), pulmonary artery systolic pressure (PASP), and myocardial velocities] and invasive blood pressure (BP). Arterial gases and B-type natriuretic peptide (BNP) were measured at baseline and peak exercise. Pulmonary vascular resistance (PVR) was determined as the regression of PASP/CO and was compared according to athletic and PTAC status. At peak exercise, athletes had greater CO (16.0 ± 2.9 vs. 12.4 ± 3.2 l/min, P < 0.001) and higher PASP (60.8 ± 12.6 vs. 47.0 ± 6.5 mmHg, P < 0.001), but PVR was similar to nonathletes (P = 0.71). High PTAC (defined by contrast filling of the left ventricle) occurred in a similar proportion of athletes and nonathletes (18/40 vs. 10/15, P = 0.35) and was associated with higher peak-exercise CO (16.1 ± 3.4 vs. 13.9 ± 2.9 l/min, P = 0.010), lower PASP (52.3 ± 9.8 vs. 62.6 ± 13.7 mmHg, P = 0.003), and 37% lower PVR (P < 0.0001) relative to low PTAC. Right ventricular (RV) myocardial velocities increased more and BNP increased less in high vs. low PTAC subjects. On multivariate analysis, maximal oxygen consumption (VO(2max)) (P = 0.009) and maximal exercise output (P = 0.049) were greater in high PTAC subjects. An exercise-induced decrease in arterial oxygen saturation (98.0 ± 0.4 vs. 96.7 ± 1.4%, P < 0.0001) was not influenced by PTAC status (P = 0.96). Increased PTAC during exercise is a marker of pulmonary vascular reserve reflected by greater flow, reduced PVR, and enhanced RV function.
authors: Department of Medicine, St. Vincent's Hospital, University of Melbourne, Melbourne, Australia. Andre.LaGerche@svhm.org.au
authors: André
authors: A
authors: La Gerche
authors: Andrew I
authors: AI
authors: MacIsaac
authors: Andrew T
authors: AT
authors: Burns
authors: Don J
authors: DJ
authors: Mooney
authors: Warrick J
authors: WJ
authors: Inder
authors: Jens-Uwe
authors: JU
authors: Voigt
authors: Hein
authors: H
authors: Heidbüchel
authors: David L
authors: DL
authors: Prior
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure; D002302:Cardiac Output; D003287:Contrast Media / Q000378:metabolism; D015150:Echocardiography, Doppler; D018618:Echocardiography, Doppler, Color; D018619:Echocardiography, Doppler, Pulsed; D015444:Exercise; D005780:Gelatin / Q000097:blood; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006439:Hemodynamics; D006801:Humans; D008168:Lung / Q000098:blood supply*; D045423:Microbubbles; D009200:Myocardial Contraction; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D010313:Partial Pressure; D010807:Physical Endurance; D011237:Predictive Value of Tests; D011652:Pulmonary Circulation; D013386:Succinates / Q000097:blood; D014655:Vascular Resistance; D016278:Ventricular Function, Right
chemical_list: D015415:Biomarkers; D003287:Contrast Media; D013386:Succinates; D020097:Natriuretic Peptide, Brain; C060085:succinylated gelatin; D005780:Gelatin; D010100:Oxygen