Sex Profile and Risk Assessment With Cardiopulmonary Exercise Testing in Heart Failure: Propensity Score Matching for Sex Selection Bias.

BACKGROUND: In heart failure (HF), women show better survival despite a comparatively low peak oxygen consumption (V˙o2): this raises doubt about the accuracy of risk assessment by cardiopulmonary exercise testing (CPET) in women. Accordingly, we aimed to check (1) whether the predictive role of well-known CPET risk indexes, ie, peak V˙o2 and ventilatory response (V˙e/V˙co2 slope), is sex independent and (2) if sex-related characteristics that impact outcome in HF should be considered as associations that may confound the effect of sex on survival. METHODS: The study population consisted of 2985 patients with HF, 498 (17%) of whom were women, from the multicentre Metabolic Exercise Test Data Combined with Cardiac and Kidney Indexes (MECKI): the end point was cardiovascular death within a 3-year period. RESULTS: During the follow-up, 305 (12%) men and 39 (8%) women (P = 0.005) died, and female sex was linked to better survival on univariate analysis (P = 0.008) and independent of peak V˙o2 and V˙e/V˙co2 slope on multivariate analysis. According to propensity score matching for female sex to exclude a sex selection bias and sample discrepancy, 498 men were selected: the standardized percentage bias ranged from 20.8 (P < 0.0001) to 3.3 (P = 0.667). After clinical profile harmonizing, female sex was predictive of HF at univariate analysis. CONCLUSIONS: The low peak V˙o2 and female association with better outcome in HF might be counterfeit: the female prognostic advantage is lost when sex-specific differences are correctly taken into account with propensity score matching, suggesting that for an effective and efficient HF model, adjustment must be made for sex-related characteristics.

Assessment of cardiac resynchronization therapy response.

The present study was performed to evaluate how to assess cardiac resynchronization therapy (CRT) efficacy in chronic heart failure (CHF) through clinical, echocardiographic and exercise analysis. We analyzed 41 stable CHF (NYHA III) patients with: left bundle-branch-block, ejection fraction <35%, left-ventricular dissynchrony (by tissue-Doppler), peak oxygen consumption (VO2) <16 ml/kg/min, suitable cardiac vein (by multislice computed tomography) and no anemia or kidney failure. Patients were evaluated before and after (7+/-3 months) CRT. Two patients died. CRT responders to none of the evaluated criteria were 19.5%. The best agreement (90%) with clinical response was obtained using the presence/absence of either left-ventricular systolic volume (LVSV) or peakVO2 response. In less severe CHF (peakVO2 12-16 ml/kg/min), peakVO2 and work-load didn't change after CRT, despite echocardiographic, ventilation/carbon dioxide relationship and clinical improvement. Echocardiography and CPET are complementary for the evaluation of CRT, but not in less severe CHF patients, where the role of CPET remain uncertain.