title: Noninvasive monitoring of serial changes in pulmonary vascular resistance and acute vasodilator testing using cardiac magnetic resonance.
abstract: OBJECTIVE
  The study sought to evaluate the ability of cardiac magnetic resonance (CMR) to monitor acute and long-term changes in pulmonary vascular resistance (PVR) noninvasively.
  
  
  BACKGROUND
  PVR monitoring during the follow-up of patients with pulmonary hypertension (PH) and the response to vasodilator testing require invasive right heart catheterization.
  
  
  METHODS
  An experimental study in pigs was designed to evaluate the ability of CMR to monitor: 1) an acute increase in PVR generated by acute pulmonary embolization (n = 10); 2) serial changes in PVR in chronic PH (n = 22); and 3) changes in PVR during vasodilator testing in chronic PH (n = 10). CMR studies were performed with simultaneous hemodynamic assessment using a CMR-compatible Swan-Ganz catheter. Average flow velocity in the main pulmonary artery (PA) was quantified with phase contrast imaging. Pearson correlation and mixed model analysis were used to correlate changes in PVR with changes in CMR-quantified PA velocity. Additionally, PVR was estimated from CMR data (PA velocity and right ventricular ejection fraction) using a formula previously validated.
  
  
  RESULTS
  Changes in PA velocity strongly and inversely correlated with acute increases in PVR induced by pulmonary embolization (r = -0.92), serial PVR fluctuations in chronic PH (r = -0.89), and acute reductions during vasodilator testing (r = -0.89, p ≤ 0.01 for all). CMR-estimated PVR showed adequate agreement with invasive PVR (mean bias -1.1 Wood units,; 95% confidence interval: -5.9 to 3.7) and changes in both indices correlated strongly (r = 0.86, p < 0.01).
  
  
  CONCLUSIONS
  CMR allows for noninvasive monitoring of acute and chronic changes in PVR in PH. This capability may be valuable in the evaluation and follow-up of patients with PH.
authors: Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Imaging in Experimental Cardiology Laboratory (IExC Lab), Madrid, Spain; Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) Epidemiology, Atherothrombosis and Imaging Department, Madrid, Spain; Hospital Clínic, IDIBAPS, Barcelona, Spain.
authors: Ana
authors: A
authors: García-Álvarez
authors: Leticia
authors: L
authors: Fernández-Friera
authors: José Manuel
authors: JM
authors: García-Ruiz
authors: Mario
authors: M
authors: Nuño-Ayala
authors: Daniel
authors: D
authors: Pereda
authors: Rodrigo
authors: R
authors: Fernández-Jiménez
authors: Gabriela
authors: G
authors: Guzmán
authors: Damián
authors: D
authors: Sanchez-Quintana
authors: Angel
authors: A
authors: Alberich-Bayarri
authors: David
authors: D
authors: Pastor-Escuredo
authors: David
authors: D
authors: Sanz-Rosa
authors: Jaime
authors: J
authors: García-Prieto
authors: Jesús G
authors: JG
authors: Gonzalez-Mirelis
authors: Gonzalo
authors: G
authors: Pizarro
authors: Luis Jesús
authors: LJ
authors: Jimenez-Borreguero
authors: Valentín
authors: V
authors: Fuster
authors: Javier
authors: J
authors: Sanz
authors: Borja
authors: B
authors: Ibáñez
mesh_terms: D000818:Animals; D002407:Catheterization, Swan-Ganz / Q000379:methods; D008297:Male; D008991:Monitoring, Physiologic; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D010865:Pilot Projects; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000503:physiopathology*; D013552:Swine; D013997:Time Factors; D014655:Vascular Resistance / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*
keywords: CMR; PA; PCWP; PH; PVR; RHC; RV; WU; Wood units; cardiac magnetic resonance; magnetic resonance; monitoring; pulmonary artery; pulmonary capillary wedge pressure; pulmonary hypertension; pulmonary vascular resistance; right heart catheterization; right ventricular; vasodilator testing