The consequences of phrenic nerve paralysis vary from a considerable reduction in respiratory function to an apparently normal state. Acoustic analysis of lung sound intensity (LSI) could be an indirect non-invasive measurement of respiratory muscle function, comparing activity on the two sides of the thoracic cage. Lung sounds and airflow were recorded in ten males with unilateral phrenic paralysis and ten healthy subjects (5 men/5 women), during progressive increasing airflow maneuvers. Subjects were in sitting position and two acoustic sensors were placed on their back, on the left and right sides. LSI was determined from 1.2 to 2.4 L/s between 70 and 2000 Hz. LSI was significantly greater on the normal (19.3±4.0 dB) than the affected (5.7±3.5 dB) side in all patients (p = 0.0002), differences ranging from 9.9 to 21.3 dB (13.5±3.5 dB). In the healthy subjects, the LSI was similar on both left (15.1±6.3 dB) and right (17.4±5.7 dB) sides (p = 0.2730), differences ranging from 0.4 to 4.6 dB (2.3±1.6 dB). There was a positive linear relationship between the LSI and the airflow, with clear differences between the slope of patients (about 5 dB/L/s) and healthy subjects (about 10 dB/L/s). Furthermore, the LSI from the affected side of patients was close to the background noise level, at low airflows. As the airflow increases, the LSI from the affected side did also increase, but never reached the levels seen in healthy subjects. Moreover, the difference in LSI between healthy and paralyzed sides was higher in patients with lower FEV1 (%). The acoustic analysis of LSI is a relevant non-invasive technique to assess respiratory function. This method could reinforce the reliability of the diagnosis of unilateral phrenic paralysis, as well as the monitoring of these patients.
Marfan syndrome (MFS) is a systemic connective tissue disorder caused by mutations in the fibrillin‐1 (FBN1) gene, and cardiovascular involvement is the leading cause of mortality. We sought to examine the genotype/phenotype realtionship in 61 consecutive patients with a phenotype and genotype compatible with MFS. The FBN1 gene was analyzed by massive sequencing using a hybridization capture‐based target enrichment custom panel. Forty‐three different variants of FBN1 were identified, of which 17 have not been previously reported. The causal variants of MFS were grouped into mutations resulting in haploinsufficiency (HI group; 23 patients) and mutations producing a dominant‐negative effect (DN group; 38 patients). Patient information was collected from electronic medical records and clinical evaluation. While no significant differences were found between the two groups, the HI group included more cases with aortic dissection and occurring at a younger age that the DN group (34.7% vs. 15.8%; p = 0.160). Irrespective of the mutation group, males presented with a higher probability of aortic involvement (4‐fold higher risk than females) and aortic dissections events occurred at younger ages. Patients with DN variants carrying a cysteine substitution had a higher incidence of ectopia lentis.
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