title: A novel expression of exercise induced pulmonary hypertension in human immunodeficiency virus patients: a pilot study.
abstract: BACKGROUND
  Patients with the human immunodeficiency virus (HIV) are at risk for multiple pulmonary complications including pulmonary hypertension. Exercise induced pulmonary hypertension (EIPH) has been previously described in patients with scleroderma, sickle cell disease and chronic obstructive pulmonary disease, yet has not been associated with the HIV population.
  
  
  METHODS
  A prospective case-control study design was implemented. Four HIV patients with unexplained dyspnea and four healthy controls underwent symptom-limited stationary bicycle exercise. Transthoracic Doppler Echocardiography was used to measure tricuspid regurgitation velocity which was used to calculate the right ventricular to right atrial pressure (RV-RA) gradient at rest and at peak exercise using the simplified Bernoulli's equation. Change in RV-RA gradient between rest and peak exercise was calculated and considered to represent change in pulmonary arterial systolic pressure.
  
  
  RESULTS
  The mean age was 41.25 years (±8.7) for patients and 33.5 years (±6.0) for controls. The mean CD4 count of patients was 191.5 cells/μL (±136.2). Patients had a significantly higher increase in RV-RA gradient as compared to controls (180.2% vs. 27.5%, p = 0.03).
  
  
  CONCLUSIONS
  This pilot study suggests that it is feasible to use recumbent bicycle and transthoracic Doppler echocardiography for the evaluation of EIPH among HIV patients with dyspnea of unknown etiology. The study is too small to draw any broad conclusion. Further evaluation of this concept with a larger study is warranted.
authors.affiliation: Rush University Medical Center, Department of Medicine, Section of Cardiology, 1653 W. Congress Pkwy, Jelke 1015, Chicago, IL 60612, USA.
authors.forename: Rami
authors.initials: R
authors.lastname: Doukky
authors.forename: Won Y
authors.initials: WY
authors.lastname: Lee
authors.forename: Mahindhar
authors.initials: M
authors.lastname: Ravilla
authors.forename: Omar B
authors.initials: OB
authors.lastname: Lateef
authors.forename: Victor
authors.initials: V
authors.lastname: Pelaez
authors.forename: Audrey
authors.initials: A
authors.lastname: French
authors.forename: Rajive
authors.initials: R
authors.lastname: Tandon