Cardiopulmonary exercise testing demonstrates maintenance of exercise capacity in patients with hypoxemia and pulmonary arteriovenous malformations

BACKGROUND: Patients with pulmonary arteriovenous malformations (PAVMs) are unusual because hypoxemia results from right-to-left shunting and not airway or alveolar disease. Their surprisingly well-preserved exercise capacity is not generally appreciated.

METHODS: To examine why exercise tolerance is preserved, cardiopulmonary exercise tests were performed while breathing room air in 21 patients with radiologically proven PAVMs, including five restudied 3 to 12 months after embolization when their PAVMs had regressed. Where physiologic matching was demonstrable, comparisons were made with 12 healthy control subjects.

RESULTS: The majority of patients achieved their predicted work rate despite a resting arterial oxygen saturation (SaO₂) of 80% to 96%. Peak work rate and oxygen consumption (VO₂) were no lower in patients with more hypoxemia. Despite higher SaO₂ following embolization (median, 96% and 90%; P = .009), patients achieved similar work rates and similar peak VO₂. Strikingly, treated patients reset to virtually identical peak oxygen pulses (ie, VO₂ per heart beat) and in many cases to the same point on the peak oxygen pulse/work rate plot. The 21 patients had increased minute ventilation (VE) for given increases in CO₂ production (VE/VCO₂ slope), but perceived dyspnea was no greater than in the 12 control subjects or in the same patients before compared to after embolization comparison. Overall, work rate and peak VO₂ were associated not with oxygenation parameters but with VE/VCO₂ slope, BMI, and anaerobic threshold.

CONCLUSIONS: Patients with hypoxemia and PAVMs can maintain normal oxygen delivery/VO₂ during peak exercise. Following improvement of SaO₂ by embolization, patients appeared to reset compensatory mechanisms and, as a result, achieved similar peak VO₂ per heart beat and peak work rates.

Medienart:

E-Artikel

Erscheinungsjahr:

2014

Erschienen:

2014

Enthalten in:

Zur Gesamtaufnahme - volume:146

Enthalten in:

Chest - 146(2014), 3 vom: 07. Sept., Seite 709-718

Sprache:

Englisch

Beteiligte Personen:

Howard, Luke S G E [VerfasserIn]
Santhirapala, Vatshalan [VerfasserIn]
Murphy, Kevin [VerfasserIn]
Mukherjee, Bhashkar [VerfasserIn]
Busbridge, Mark [VerfasserIn]
Tighe, Hannah C [VerfasserIn]
Jackson, James E [VerfasserIn]
Hughes, J Michael B [VerfasserIn]
Shovlin, Claire L [VerfasserIn]

Links:

Volltext

Themen:

142M471B3J
Carbon Dioxide
Journal Article
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 13.01.2015

Date Revised 03.06.2017

published: Print

Citation Status MEDLINE

doi:

10.1378/chest.13-2988

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM236832387