Maximal exercise oxygen pulse as a predictor of mortality among male veterans referred for exercise testing.
BACKGROUND
Maximal oxygen pulse (O(2) pulse) mirrors the stroke volume response to exercise, and should therefore be a strong predictor of mortality. Limited and conflicting data are, however, available on this issue.


METHODS
Nine hundred forty-eight participants, classified as those with cardiopulmonary disease (CPD) and those without (non-CPD), underwent cardiopulmonary exercise testing (CPX) for clinical reasons between 1993 and 2003. The ability of maximal O(2) pulse and maximal oxygen uptake (peak VO(2)) to predict mortality was investigated using proportional hazards and Akaike information criterion analyses. All-cause mortality was the endpoint.


RESULTS
Over a mean follow-up of 6.3+/-3.2 years, there were 126 deaths. Maximal O(2) pulse, expressed in either absolute or relative to age-predicted terms, and peak VO(2) were significant and independent predictors of mortality in those with and without CPD (P<0.04). Akaike information criterion analysis revealed that the model including both maximal O(2) pulse and peak VO(2) had the highest accuracy for predicting mortality. The optimal cut-points for O(2) pulse and peak VO(2) (<12; > or =12 ml/beat and <16; > or =16 ml/(kg.min) respectively) were established by the area under the receiver-operating-characteristic curve. The relative risks of mortality were 3.4 and 2.2 (CPD and non-CPD, respectively) among participants with both maximal O(2) pulse and peak VO(2) responses below these cut-points compared with participants with both responses above these cut-points.


CONCLUSIONS
These results indicate that maximal O(2) pulse is a significant predictor of mortality in patients with and without CPD. The addition of absolute and relative O(2) pulse data provides complementary information for risk-stratifying heterogeneous participants referred for CPX and should be routinely included in the CPX report.
Oliveira
Ricardo B
RB
Gama Filho University, Rio de Janeiro, Brazil. ricardobrandaorj@gmail.com
Myers
Jonathan
J
Araújo
Claudio Gil S
CG
Abella
Joshua
J
Mandic
Sandra
S
Froelicher
Victor
V
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D001835:Body Weight; D005080:Exercise Test; D006331:Heart Diseases / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality*; D006339:Heart Rate; D006801:Humans; D053208:Kaplan-Meier Estimate; D008171:Lung Diseases / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012017:Referral and Consultation; D018570:Risk Assessment; D013997:Time Factors; D014728:Veterans
D000319:Adrenergic beta-Antagonists