Value of Plethysmographic Pulse Amplitude Ratio With Valsalva Maneuver in Identifying Left Ventricular Dysfunction During COPD Exacerbation

BACKGROUND: Left-ventricular dysfunction associated with COPD exacerbation is frequently underestimated. We tested whether finger plethysmography waveform change during the Valsalva maneuver could aid in the distinction between patients with COPD exacerbation with and without left ventricular dysfunction. METHODS: We included 102 subjects with COPD exacerbation and 51 subjects with acute heart failure admitted to the emergency department for acute dyspnea. Measurements of the plethysmographic pulse amplitude ratio under the Valsalva maneuver were obtained. The value of the plethysmographic pulse amplitude ratio in diagnosing left-ventricular dysfunction in COPD exacerbation subjects was quantified using the area under the receiver operating characteristic curves. Diagnostic performance of the plethysmographic pulse amplitude ratio was compared with the Boston score, and the net reclassification improvement was calculated to determine the incremental value in detecting left-ventricular dysfunction. RESULTS: Values of the plethysmographic pulse amplitude ratio were higher in COPD exacerbation subjects with left-ventricular dysfunction compared with those without left-ventricular dysfunction (0.78 vs 0.38, P = .01) but not significantly different from those of the acute heart failure group (0.78). There was a significant correlation between plethysmographic pulse amplitude ratio values and brain natriuretic peptide serum levels. The area under the receiver operating characteristic curve for the plethysmographic pulse amplitude ratio to detect left-ventricular dysfunction among subjects with COPD exacerbation was significantly higher compared with that of the Boston score (0.92 vs 0.76, P = .02). Exposure to plethysmographic pulse amplitude ratio values increased the overall accuracy from Boston score-based predictions of left-ventricular dysfunction and provided a net reclassification improvement of 17.3 %. CONCLUSIONS: An increased plethysmographic pulse amplitude ratio associated with COPD exacerbation is a good predictor of left-ventricular dysfunction. This simple and noninvasive index could help emergency department physicians to detect or rule out left ventricular dysfunction in patients with COPD exacerbation who are able to perform the Valsalva maneuver. (ClinicalTrials.gov registration NCT01619540.)