Endothelin-1, vascular endothelial growth factor and systolic pulmonary artery pressure in patients with Chuvash polycythemia.

BACKGROUND AND OBJECTIVES: Endothelin-1 has been associated with development of hypoxia-related pulmonary hypertension and vascular endothelial growth factor (VEGF) with protection from this complication. In Chuvash polycythemia, homozygous germline von Hippel-Lindau (VHL) 598C->T leads to up-regulation during normoxia of hypoxia inducible factor-1a and several hypoxia-controlled genes including erythropoietin and VEGF. We postulated that endothelin-1 and pulmonary artery pressure may be elevated in Chuvash polycythemia. DESIGN AND METHODS: Systolic pulmonary artery blood pressure was estimated by Doppler echocardiography and plasma concentrations of endothelin-1, VEGF and erythropoietin were determined in 14 patients with Chuvash polycythemia and 14 controls. Results. Plasma endothelin-1 (p=0.010), VEGF (p=0.022) and erythropoietin (p<0.0005) concentrations and Doppler-estimated systolic pulmonary artery pressures (p<0.0005) were higher in the patients while systolic systemic blood pressures were lower (p=0.001). Five (36%) patients and no controls had mild pulmonary hypertension defined as systolic pulmonary artery pressure (c) 35 mmHg. Among the patients with Chuvash polycythemia, the trends of association of estimated pulmonary artery pressure with plasma concentrations of endothelin-1 (R = +0.236), VEGF (R = -0.389) and erythropoietin (R = +0.220) were not statistically significant. INTERPRETATIONS AND CONCLUSIONS: Estimated systolic pulmonary artery pressure and plasma concentrations of endothelin-1 and VEGF are increased in patients with Chuvash polycythemia patients. The lack of significant associations of estimated systolic pulmonary artery pressure with plasma endothelin-1 and VEGF levels could conceivably be due to the small sample size. Further studies are indicated, especially in view of the reported efficacy of endothelin-1 receptor blockers in treating hypoxia-associated pulmonary hypertension.

Small Steps in Impacting Clinical Auscultation of Medical Students.

The objective of this study was to determine if a training module improves the auscultation skills of medical students at the University of Maryland School of Medicine. Second-year medical students completed pretests on 12 heart sounds followed by a 45-minute training module on clinical auscultation, with retesting immediately after the intervention and during their third-year pediatrics clerkship. The control group consisted of third-year medical students who did not have the intervention. There was a 23% improvement in the identification of heart sounds postintervention (P < .001). Diastolic and valvular murmurs were poorly identified pre- and post intervention. There was a 6% decline in accuracy of the intervention group in the following academic year. The intervention group was superior to the control group at identifying the tested heart sounds (49% vs 43%, P = .04). The accuracy of second-year medical students in identifying heart sounds improved after a brief training module.