Pulmonary vascular reactivity and prognosis in patients with chronic thromboembolic pulmonary hypertension: a pilot study.

BACKGROUND: Surgical pulmonary endarterectomy is the preferred treatment for chronic thromboembolic pulmonary hypertension. Persistent pulmonary hypertension after pulmonary endarterectomy has been recognized as a major determinant of poor outcome. We tested whether acute vasoreactivity identifies chronic thromboembolic pulmonary hypertension patients prone to develop persistent/recurrent pulmonary hypertension after pulmonary endarterectomy and whether the degree of acute vasoreactivity affects survival or freedom from lung transplantation. METHODS AND RESULTS: Right-sided heart catheterization at baseline and after inhalation of 40 ppm nitric oxide for 20 minutes was performed in 103 patients (56.3+/-15.3 years old, 53 women). Reductions in mean pulmonary arterial pressure (DeltamPAP; -8.8+/-12.6%; P<0.0001) and pulmonary vascular resistance (-16.1+/-18.1%; P<0.0001) and an increase in mixed venous saturation during inhaled nitric oxide (9.1+/-11.6%; P<0.0001) were observed. Sixty-two patients underwent pulmonary endarterectomy after a median of 49 days (25th and 75th percentiles: 24 and 123 days). Operated patients were followed up for a median of 70.9 months (25th and 75th percentiles: 14 and 97 months). Change in mPAP during inhaled NO was identified as a predictor of persistent/recurrent pulmonary hypertension after pulmonary endarterectomy. Patients experiencing a reduction in mPAP >10.4% with nitric oxide inhalation had a better postoperative outcome. A significant correlation was found between DeltamPAP and immediate postoperative pulmonary vascular resistance (r=0.5, P<0.0001). CONCLUSIONS: A total of 80 (77.7%) of 103 patients demonstrated acute pulmonary vascular reactivity of some degree. A decrease in mPAP >10.4% under inhaled nitric oxide is a predictor of long-term survival and freedom from lung transplantation in adult patients with chronic thromboembolic pulmonary hypertension who are undergoing pulmonary endarterectomy.

Mechanical properties of the Schneiderian membrane in vitro.

OBJECTIVES: Perforation of the Schneiderian membrane (maxillary sinus mucosa) is a common complication of maxillary sinus graft procedures. Membrane perforation increases the chance of postoperative sinusitis and endangers graft as well as implant survival. The aim of the present study was to explore the mechanical properties of the Schneiderian membrane. MATERIAL AND METHODS: Three test methods were performed on sinus specimen of 20 fresh human cadavers: one- and two-dimensional membrane elongation as far as perforation, as well as membrane detachment from the adherent bone. RESULTS: Perforation of the Schneiderian membrane (mean thickness: 90 mum) occurred at a mean tension of 7.3 N/mm(2). The membrane could be stretched to 132.6% of its original size in one-dimensional elongation, and to 124.7% in two-dimensional elongation. Thicker membranes demonstrated significantly higher load limits (P<0.001). The mean modulus of elasticity accounted 0.058 GPa, the mean adhesion force between sinus membrane and bone surface was 0.05 N/mm. CONCLUSIONS: Respecting the mechanical properties of the Schneiderian membrane may help reducing the complication rates and thus patient morbidity in minimally invasive maxillary sinus floor elevation.