Noninvasive Pulmonary Hemodynamic Evaluation in Athletes With Exercise-Induced Hypoxemia

Area of Science:

• Cardiovascular Physiology
• Pulmonary Medicine
• Sports Science

Background:

• Exercise-induced hypoxemia (EIH) in athletes may stem from pulmonary capillary stress failure.
• Specific pulmonary vascular properties in athletes with EIH are not well understood.

Purpose of the Study:

• To investigate pulmonary vascular function differences in endurance athletes with and without EIH.
• To explore the relationship between pulmonary vascular properties and exercise-induced oxygen desaturation.

Main Methods:

• Compared endurance athletes with EIH (n=10), without EIH (n=9), and untrained controls (n=10).
• Utilized incremental exercise stress echocardiography, lung diffusion capacity for carbon monoxide (Dlco) and nitric oxide (Dlno) testing.
• Assessed pulmonary vascular pressure, resistance, cardiac output, and distensibility (alpha).

Main Results:

• EIH athletes had a smaller decrease in pulmonary vascular resistance (PVR) during exercise and higher maximal mean pulmonary arterial pressure (mPAP).
• Pulmonary vascular distensibility (alpha) was lower in EIH athletes.
• Maximal mPAP, pulmonary capillary pressure (Pcap), and alpha correlated with the fall in oxygen saturation (Spo2).

Conclusions:

• EIH athletes exhibit distinct pulmonary vascular characteristics, including higher pressures and reduced distensibility.
• These findings support hypotheses of pulmonary capillary stress failure or intrapulmonary shunting in athletes with EIH.
• Pulmonary vascular function is a key factor in exercise-induced hypoxemia in endurance athletes.