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.).

Functional G894T (rs1799983) polymorphism and intron-4 VNTR variant of nitric oxide synthase (NOS3) gene are susceptibility biomarkers of obesity among Tunisians.

OBJECTIVE: The endothelial nitric oxide synthase (NOS3) has been shown to play a role in the modulation of lipolysis. The goal of this study was to examine the impact of the G894T (rs1799983) and a 27 bp variable number of tandem repeats (VNTR 4a/b) of NOS3 gene on obesity in a sample of the Tunisian population. RESEARCH METHODS AND PROCEDURES: The study included 211 normal weight subjects and 183 obese patients. NOS3 G894T and 4a/b variants were determined by PCR analysis and examined for association with obesity-related traits. The effect of obesity on forearm skin blood flow (FSBF) response to acetylcholine, an endothelium-dependent vasodilator was determined by laser Doppler iontophoresis. RESULTS: In case-control studies, both G894T and 4a/b variants were associated with obesity. A significantly increased risk of obesity was found with the NOS3(G894T) TT genotype (OR:2.62, P=0.04). This association remains significant after adjustments for age and gender (OR: 2.93, P=0.03). A higher risk was also observed for carriers of the G894T allele (OR: 1.72, P=0.001). Stratified analysis by gender revealed that obese men (but not women) had significantly higher frequency of TT genotypes compared to controls (9.9% vs. 2.9%, P=0.01). Carriers of the 4b allele presented a significantly higher risk of obesity than non-carriers even after adjustments for age and gender (OR (95%CI): 1.72 (1.16-2.56), P=0.004). Correlations with anthropometric parameters revealed that carriers of TT and bb genotypes had significantly higher body mass index compared to those homozygous for the G and a alleles (P=0.0004). CONCLUSION: This study provides the first evidence for the association of G894T and 4a/b variants with body mass index and the risk of obesity in Tunisians. These polymorphisms did not exhibit, however any significant association with both metabolic traits and vascular function.