Primary Open Versus Closed Implantation Strategy for Totally Implantable Venous Access Ports: The Multicentre Randomized Controlled PORTAS-3 Trial (DRKS 00004900).

OBJECTIVES: PORTAS-3 was designed to compare the frequency of pneumothorax or haemothorax in a primary open versus closed strategy for port implantation. BACKGROUND DATA: The implantation strategy for totally implantable venous access ports with the optimal benefit/risk ratio remains unclear. METHODS: PORTAS-3 was a multicentre, randomized, controlled, parallel-group superiority trial. Adult patients with oncological disease scheduled for elective port implantation were randomized to a primary open or closed strategy. Primary endpoint was the rate of pneumothorax or haemothorax. Assuming a difference of 2.5% between the 2 groups, a sample size of 1154 patients was needed to prove superiority of the open group. A logistic regression model after the intention-to-treat principle was applied for analysis of the primary endpoint. RESULTS: Between November 9, 2014 and September 5, 2016, 1205 patients were randomized. Of these, 1159 (open n = 583; closed n = 576) were finally analyzed. The rate of pneumothorax or haemothorax was significantly reduced with the open strategy [odds ratio 0.27, 95% confidence interval (CI) 0.09-0.88; P = 0.029]. Operation time was shorter for the closed strategy. Primary success rates, tolerability, morbidity, dose rate of radiation, and 30-day mortality did not differ significantly between the groups. CONCLUSION: A primary open strategy by cut-down of the cephalic vein, if necessary enhanced by a modified Seldinger technique, reduces the frequency of pneumothorax or haemothorax after central venous port implantation significantly compared with a closed strategy by primary puncture of the subclavian vein without routine sonographic guidance. Therefore, open surgical cut-down should be the reference standard for port implantation in comparable cohorts. TRIAL REGISTRATION: German Clinical Trials Register DRKS 00004900.

Infection with an acanthocephalan manipulates an amphipod's reaction to a fish predator's odours.

Many parasites with complex life cycles increase the chances of reaching a final host by adapting strategies to manipulate their intermediate host's appearance, condition or behaviour. The acanthocephalan parasite Pomphorhynchus laevis uses freshwater amphipods as intermediate hosts before reaching sexual maturity in predatory fish. We performed a series of choice experiments with infected and uninfected Gammarus pulex in order to distinguish between the effects of visual and olfactory predator cues on parasite-induced changes in host behaviour. When both visual and olfactory cues, as well as only olfactory cues were offered, infected and uninfected G. pulex showed significantly different preferences for the predator or the non-predator side. Uninfected individuals significantly avoided predator odours while infected individuals significantly preferred the side with predator odours. When only visual contact with a predator was allowed, infected and uninfected gammarids behaved similarly and had no significant preference. Thus, we believe we show for the first time that P. laevis increases its chance to reach a final host by olfactory-triggered manipulation of the anti-predator behaviour of its intermediate host.