Case Report: Intrapulmonary Arteriovenous Anastomoses in COVID-19-Related Pulmonary Vascular Changes: A New Player in the Arena?

Up to now, COVID-19-related vascular changes were mainly described as thrombo-embolic events. A handful of researchers reported another type of vascular abnormality referred to as “vascular thickening” or “vascular enlargement,” without specifying whether the dilated vessels are arteries or veins nor providing a physiopathological hypothesis. Our observations indicate that the vascular dilatation occurs in the venous compartment, and underlying mechanisms might include increased blood flow due to inflammation and the activation of arteriovenous anastomoses.

Influence of blood Po2 on the stability of agitated saline contrast

Hyperoxic blood has a small stabilizing effect on agitated saline contrast compared with mixed venous blood, lending support to studies that show the reversal of exercise-induced blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) with hyperoxia. These data support the possible presence of a local O2-dependent regulatory mechanism within the pulmonary vasculature that may play a role in Q̇IPAVA regulation.

Experience of repeated fetoscopic laser coagulation of placental anastomoses in case of recurrence of twin-to-twin transfusion syndrome

Recurrence of twin-to-twin transfusion syndrome (TTTS) after fetoscopic laser coagulation (FLC) of placental anastomoses is unfavorable complication. Multiparous woman 34 years old in TTTS stage 2 was performed FLC of 8 arteriovenous anastomoses of the placenta followed by amnioreduction of 1000 ml on the gestational age of 22 weeks and 2 days. At gestational age of 24 weeks 6 days was revealed a recurrence of the TTTS, with considerable polyhydramnion of recipient and anhydramnion of the donor, a repeated FLC of 5 residual placental anastomoses was performed and amnioreduction of 2000 ml at 25 weeks 1 day of gestation. On the fifth day was normalized the amount of amniotic fluid of both fetuses. At 32 weeks of gestation spontaneously was began the birth, the weights of newborns were 1560 and 1600 g, both had Apgar score 8/9. Respiratory therapy continued for 7 hours at the second newborn and for 13 hours at the first newborn girl after transferring to the ICU. The signs of the respiratory failure were not observed. There were no differences between complete blood counts. This clinical case confirms the possibility of effective correction of recurrence TTTS with the help of repeated FLC of placental anastomoses.

PS01.171: DOUBLE-PEDICLED FREE JEJUNAL TRANSFER FOR RECONSTRUCTION OF PHARYNGOLARYNGOESOPHAGECTOMY

Background We recently selected double-pedicled free jejunal transfer for reconstruction of pharyngolaryngoesophagectomy to reduce the vascular thrombosis-induced necrosis in free jejunal transfer. We herein report our experience with this procedure. Methods Single-pedicled free jejunal transfer for reconstruction of pharyngolaryngoesophagectomy was performed from January 2006 to November 2013, and double-pedicled free jejunal transfer (i.e. two pairs of jejunal arteriovenous anastomoses) was performed from December 2013 to December 2016 in Kansai Medical University Hospital. We compared the perioperative outcomes and complications between these two procedures. Results Sixty-two patients (58 men, 4 women; median age, 66 years; age range, 51–83 years) underwent single-pedicled free jejunal transfer. Twenty-eight patients (25 men, 3 women; median age, 70 years; age range, 47–84 years) underwent double-pedicled free jejunal transfer. Twenty-eight patients received preoperative treatments. Table 1 shows the perioperative outcomes and complications. Conclusion No thrombus of the free jejunum occurred, no anastomotic leakage occurred, and all flaps survived in the double-pedicled free jejunal transfer group. We believe that double-pedicled free jejunal transfer for reconstruction of pharyngolaryngoesophagectomy is a reliable and useful procedure. Disclosure All authors have declared no conflicts of interest.

AltitudeOmics: effect of reduced barometric pressure on detection of intrapulmonary shunt, pulmonary gas exchange efficiency, and total pulmonary resistance

Blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA) occurs in healthy humans at rest and during exercise when breathing hypoxic gas mixtures at sea level and may be a source of right-to-left shunt. However, at high altitudes, QIPAVA is reduced compared with sea level, as detected using transthoracic saline contrast echocardiography (TTSCE). It remains unknown whether the reduction in QIPAVA (i.e., lower bubble scores) at high altitude is due to a reduction in bubble stability resulting from the lower barometric pressure (PB) or represents an actual reduction in QIPAVA. To this end, QIPAVA, pulmonary artery systolic pressure (PASP), cardiac output (QT), and the alveolar-to-arterial oxygen difference (AaDO2) were assessed at rest and during exercise (70–190 W) in the field (5,260 m) and in the laboratory (1,668 m) during four conditions: normobaric normoxia (NN; [Formula: see text] = 121 mmHg, PB = 625 mmHg; n = 8), normobaric hypoxia (NH; [Formula: see text] = 76 mmHg, PB = 625 mmHg; n = 7), hypobaric normoxia (HN; [Formula: see text] = 121 mmHg, PB = 410 mmHg; n = 8), and hypobaric hypoxia (HH; [Formula: see text] = 75 mmHg, PB = 410 mmHg; n = 7). We hypothesized QIPAVA would be reduced during exercise in isooxic hypobaria compared with normobaria and that the AaDO2 would be reduced in isooxic hypobaria compared with normobaria. Bubble scores were greater in normobaric conditions, but the AaDO2 was similar in both isooxic hypobaria and normobaria. Total pulmonary resistance (PASP/QT) was elevated in HN and HH. Using mathematical modeling, we found no effect of hypobaria on bubble dissolution time within the pulmonary transit times under consideration (<5 s). Consequently, our data suggest an effect of hypobaria alone on pulmonary blood flow. NEW & NOTEWORTHY Blood flow through intrapulmonary arteriovenous anastomoses, detected by transthoracic saline contrast echocardiography, was reduced during exercise in acute hypobaria compared with normobaria, independent of oxygen tension, whereas pulmonary gas exchange efficiency was unaffected. Modeling the effect(s) of reduced air density on contrast bubble lifetime did not result in a significantly reduced contrast stability. Interestingly, total pulmonary resistance was increased by hypobaria, independent of oxygen tension, suggesting that pulmonary blood flow may be changed by hypobaria.