Volgens een presentatie van Betsy Keller op de recente IACFS-ME conferentie
kunnen we CVS-patiënten op basis van de dubbele fietstest in vier groepen indelen:
- patiënten waarvan de maximale zuurstofopname de tweede dag beduidend lager is (34%) en/of
- patiënten waarvan de zuurstofopname bij de verzuringsdrempel sterk afneemt (39%) en/of,
- patiënten die op een andere wijze abnormaal reageren op de dubbele fietstest, en
- patiënten die bij de tweede inspaningstest vergelijkbaar presteren/niet achteruit gaan (29%)
De vierde groep zou nader onderzocht moeten worden,
wellicht omdat deze CVS-patiënten wel normaal reageren op 'revalidatieprogramma's'.
Subsets of ME/CFS patient responses to a 2-day CPET
IACFS/ME Conference, 2016 October 27-30. Fort Lauderdale, Florida.
Betsy Keller.
Betsy Keller,
Professor,
Department of Exercise and Sport Sciences,
Ithaca College,
318 Center for Health Sciences,
Ithaca,
NY 14850
Background:
Studies to assess the efficacy of a two-day cardiopulmonary exercise test (2-d CPET) protocol
to identify post-exertion malaise (PEM) in ME/CFS
first revealed that ME/CFS patients often fail to reproduce peak VO2 (VO2peak) during test 2
due to PEM provoked with test 1.
Subsequent research indicated that a subset of patients
failed to reproduce VO2 at ventilatory/anaerobic threshold (VAT),
but did reproduce VO2peak,
suggesting that responses to exertion may distinguish subsets of patients.
Identifying subsets of ME/CFS patient responses to exertion
would enable us to further explore other potential correlates,
such as metabolic markers or bacterial microbiome of the gut.
Objectives:
To classify the responses of ME/CFS patients to a 2-d CPET protocol
to determine if ME/CFS patients demonstrate subsets of responses
in addition to failure to reproduce VO2peak or VO2@VAT.
Methods:
Responses to a 2-d CPET protocol were evaluated for 94 ME/CFS patients.
Patient responses were evaluated based on failure to reproduce VO2peak or VO2@VAT,
as well as failure to respond normally with regard to
autonomic parameters (heart rate, blood pressure),
ventilatory parameters,
as well as cases that reproduced CPETs within normal variation.
Results:
Of 97 cases,
34% comprised a subset of responders that failed to reproduce VO2peak, and
39% failed to reproduce VO2@VAT within normal variation.
Additionally, subsets were also described by
autonomic anomalies (43%), ventilatory anomalies (47%), and
normal reproduction of CPETs (29%).
Membership in more than one subset by several cases explained
the sum total of all subsets greater than 100%.
Conclusion:
Assessment of PEM using the 2-d CPET protocol
should consider abnormal responses to exertion that extend
beyond VO2peak or VO2@VAT and
consider disruption of autonomic and ventilatory responses
as indicators of inappropriate recovery, or PEM, following exertion.
Additionally, patients diagnosed with ME/CFS
who reproduce the 2-day CPET within normal parameters
may describe a unique subset that requires further study.
Preliminary data will be discussed
which indicates that this subset may correspond with other prognostic indicators.
http://iacfsme.org/ME-CFS-Primer-Education/News/IACFSME-2016-Program.aspx
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