Abstract
AimHuman Immunodeficiency Virus (HIV) patients commonly experience dyspnea for which an immediate cause may not be always apparent. In this prospective cohort study of HIV patients with exercise limitation, we use cardiopulmonary exercise testing (CPET) coupled with exercise cardiovascular magnetic resonance (CMR) to elucidate etiologies of dyspnea.Methods and resultsThirty-four HIV patients on antiretroviral therapy with dyspnea and exercise limitation (49.7 years, 65% male, mean absolute CD4 count 700) underwent comprehensive evaluation with combined rest and maximal exercise treadmill CMR and CPET. The overall mean oxygen consumption (VO2) peak was reduced at 23.2 ± 6.9 ml/kg/min with 20 patients (58.8% of overall cohort) achieving a respiratory exchange ratio > 1. The ventilatory efficiency (VE)/VCO2 slope was elevated at 36 ± 7.92, while ventilatory reserve (VE: maximal voluntary ventilation (MVV)) was within normal limits. The mean absolute right ventricular (RV) and left ventricular (LV) contractile reserves were preserved at 9.0% ± 11.2 and 9.4% ± 9.4, respectively. The average resting and post-exercise mean average pulmonary artery velocities were 12.2 ± 3.9 cm/s and 18.9 ± 8.3 respectively, which suggested lack of exercise induced pulmonary artery hypertension (PAH). LV but not RV delayed enhancement were identified in five patients. Correlation analysis found no relationship between peak VO2 measures of contractile RV or LV reserve, but LV and RV stroke volume correlated with PET CO2 (p = 0.02, p = 0.03).ConclusionWell treated patients with HIV appear to have conserved RV and LV function, contractile reserve and no evidence of exercise induced PAH. However, we found evidence of impaired ventilation suggesting a non-cardiopulmonary etiology for dyspnea.
Highlights
Unexplained dyspnea in patients with human immunodeficiency virus (HIV) can be multifactorial and may portend a poor prognosis especially with diagnoses such as HIV pulmonary arterial (PA) hypertension (PAH) [1,2,3]
We evaluated HIV patients with subjective exercise limitation, with no other obvious evidence of cardiopulmonary disease to comprehensively assess ventricular contractile reserve, PA velocities and cardiopulmonary ventilatory indices using a treadmill exercise cardiovascular magnetic resonance (CMR) imaging protocol combined with cardiopulmonary exercise testing (CPET)
Contractile reserve To assess contractile reserve, left ventricular ejection fraction (LVEF) and right ventricular (RV) ejection fraction (RVEF) and stroke volumes were quantified at rest and stress
Summary
Unexplained dyspnea in patients with human immunodeficiency virus (HIV) can be multifactorial and may portend a poor prognosis especially with diagnoses such as HIV pulmonary arterial (PA) hypertension (PAH) [1,2,3]. While the gold standard for evaluation of cardiopulmonary performance and assessment of PA pressure remains invasive right heart catheterization in combination with exercise, the use of such an approach for comprehensive screening is fairly involved [7, 8] Other tools such as stress echocardiography to evaluate for changes in tricuspid valve velocities, increase in E/e’ and contractile dysfunction are often used, but are limited by imaging windows that could be suboptimal in many patients, with exercise [8]. Coupling cardiovascular magnetic resonance (CMR) with cardiopulmonary exercise testing (CPET) may allow comprehensive noninvasive functional and structural analysis of patients with dyspnea of unclear etiology and could provide valuable prognostic and diagnostic information [9] In this prospective study, we evaluated HIV patients with subjective exercise limitation, with no other obvious evidence of cardiopulmonary disease to comprehensively assess ventricular contractile reserve, PA velocities and cardiopulmonary ventilatory indices using a treadmill exercise CMR imaging protocol combined with CPET
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