Safety of Percutaneous Transmesenteric and Transsplenic Access for Portosystemic Shunt Creation in Patients with Portal Vein Obstruction: Single-Center Experience and Review of Literature

PURPOSE

To evaluate the safety of ultrasound-guided percutaneous mesenteric vein access compared to transsplenic portal vein access for portosystemic shunt placement in patients with portal vein obstruction.

MATERIALS AND METHODS

Eight patients underwent portosystemic shunt creation through either a transsplenic (n = 4) or transmesenteric (n = 4) approach. The superior or inferior mesenteric vein was percutaneously accessed under ultrasound guidance using a 21G needle and a 4F sheath. Hemostasis at the mesenteric access site was achieved with manual compression. For transsplenic access, sheath sizes between 6 and 8F were used and tract embolization with gelfoam was performed.

RESULTS

Portosystemic shunt placement was successful in all patients. While there were no bleeding complications with transmesenteric access, hemorrhagic shock requiring splenic artery embolization occurred in one patient in which the transsplenic approach was used.

CONCLUSION

Ultrasound-guided mesenteric vein access seems feasible and a valid alternative to the transsplenic access in case of portal vein obstruction. Level of Evidence Level 4, case series.

Postinterventional Patient Comfort After Uterine Artery Embolization and Superior Hypogastric Nerve Block

PURPOSE

To evaluate the duration and effect of superior hypogastric nerve block (SHNB) with ropivacaine and clonidine on postinterventional pain levels and opioid requirements in patients undergoing uterine artery embolization.

MATERIALS AND METHODS

Postinterventional pain levels (numeric rating scale, NRS 0-10) and opioid doses were retrospectively analyzed in 53 patients undergoing transfemoral uterine artery embolization and intraprocedural superior hypogastric nerve block during 24 h. A mixture of 150 mg of ropivacaine and 150 µg of clonidine was used for the block.

RESULTS

Postinterventional pain averaged between 1.4 and 2.0 during the first 9 h, after which a small but significant increase was observed (NRS 1.7 ± 1.6 vs. NRS 2.6 ± 2.2, p < 0.001). 70% of patients did not exceed a tolerable pain threshold of NRS 4 during the first 9 h after the intervention. Thirty-three patients (62%) did not require any opioid medication. Mean iv morphine dose was 3.1 ± 4.7 mg, whereas 71% of opioid doses were administered after 9 h.

CONCLUSION

Superior hypogastric nerve block using a mixture of ropivacaine and clonidine provides good pain relief for 9 h after uterine artery embolization requiring only very low amounts of additional opioids.

"Apical thinning": Relations between myocardial wall thickness and apical left ventricular tracer uptake as assessed with positron emission tomography myocardial perfusion imaging

BACKGROUND

A reduction in left ventricular apical tracer uptake (apical thinning) is frequently observed in myocardial perfusion imaging (MPI), yet its cause remains a matter of debate, particularly in perfusion emission tomography (PET). This analysis sought to determine whether apical thinning in PET-MPI is attributable to true anatomical thinning of the left ventricular apical myocardium.

METHODS AND RESULTS

We retrospectively analyzed 57 patients without any history or signs of apical myocardial infarction who underwent rest PET-MPI with 13N-ammonia and contrast-enhanced cardiac computed tomography (CT). Semi-quantitative normalized percent apical 13N-ammonia uptake at rest, myocardial blood flow (MBF), and k2 wash-out rate constants were compared to apical myocardial wall thickness measurements derived from CT and base-to-apex gradients were calculated. Apical thinning was found in 93% of patients and in 74% when analysis of normalized apical tracer uptake was confined to end-systole. No significant correlation was found between apical myocardial thickness and apical tracer uptake (r = - 0.080, P = .553), MBF (r = - 0.211, P = .115), or k2 wash-out rate (r = - 0.023, P = .872), nor between apical myocardial thickness and any gradients. A statistically significant but small difference in apical myocardial thickness was observed in patients with moderately to severely reduced apical tracer uptake vs patients with normal to mildly reduced uptake (4.3 ± 0.7 mm vs 4.7 ± 0.7 mm; P = .043).

CONCLUSIONS

Apical thinning is a highly prevalent finding during 13N-ammonia PET-MPI that is not solely attributable to true anatomical apical wall thickness or the partial volume effect. Other factors that yet need to be identified seem to have a more prominent impact.

Balloon-borne ion sampling package

A mass filter package for atmospheric sampling in the stratosphere has been designed and constructed so that ambient positive ions can be detected in one mode of operation (PI) and ambient negative ions in a second mode of operation (NI). The range of the quadrupole mass filter is 1-150 amu. Any one of the 150 mass positions can be selected for a fixed peak operation, or the total range can be covered in a continuous sweep at the rate of 300 amu/s. Filtered ions are individually counted. The atmosphere is sampled through a valved 0.03-cm-diam orifice which has a conductance of about 9 x (10(-3)) l/s and width-to-thickness ratio greater than 10. Ambient temperature, ambient pressure, atmospheric electrical conductivity, and cosmic ray ionization detectors are also part of the package. An on-board clock and logic circuitry control the gathering of data. However, the mass filter operations can also be preferentially controlled via telemetry. Data are concurrently recorded with an on-board digital tape recorder and telemetered to earth for real-time data analysis. The entire package has been designed and constructed to minimize contamination of the atmosphere being sampled. Preliminary results from a recent flight show evidence for the presence of hydrated protons in the stratosphere.