ABSTRACT
Objective: Percutaneous ultrasound-guided creation of an arteriovenous fistula (pAVF) for hemodialysis access is a relatively novel procedure with promising technical success and patency rates. The vascular surgery departments of two collaborating Swiss hospitals had decided to introduce the technique to their services. A surgeon experienced in the technique (AM) was supposed to come to Switzerland and proctor the first four procedures. Due to the SARS-CoV-2 pandemic and travel restrictions, this was not possible and we decided to perform the first four pAVF procedures tele-proctored via a video conference system. We present the setup and our experience with tele-proctoring. Methods: The setup relied on an all-in-one live video production device, video encoder, video streamer and video recorder (Pearl-2, Epiphan), which made it possible to simultaneously transmit the live image from the ultrasound device (GE Logiq S8, linear probe 9L-D) and a live image from a video camera (JVC Camcorder G/-HM440E, Japan), both connected via HDMI (Figure). The live stream was shared with the proctor in France and the device support team in the US, using an encrypted Swiss video client (www.vitimway.ch). The setup was tested with all parties three days in advance. Results: All 4 procedures started with a verbal briefing and a live ultrasound scan. All steps of the procedures were taken under the proctor's instruction and supervision. The proctor gave on average 21 instructions per procedure. An average 4 were device-related but these became less frequent as we proceeded. The operators consulted the proctor on average 5 times per procedure. The average duration of the procedure was 34 min. The pAVF creation was successful in all 4 patients, with an average fistula flow measured at the end of the procedure of 600ml/min. Conclusion: Our experience showed us that pAVF creation, which is a procedure performed entirely under sonographic guidance lends itself particularly well to tele-proctoring. The simultaneous transmission of the live sonographic image and the live image of the operators' hands allowed the proctor to supervise and correct the key steps of the procedures. The simplicity of the set-up and the quality of proctor-operator interaction was such a positive experience that we can well envisage a much wider use of tele-proctoring in the future.
ABSTRACT
Clinical manifestations of COVID-19 affect many organs, including the heart. Cardiovascular disease is a dominant comorbidity and prognostic factors predicting risk for critical courses are highly needed. Moreover, immunomechanisms underlying COVID-induced myocardial damage are poorly understood. OBJECTIVE: To elucidate prognostic markers to identify patients at risk. RESULTS: Only patients with pericardial effusion (PE) developed a severe disease course, and those who died could be identified by a high CD8/Treg/monocyte ratio. Ten out of 19 COVID-19 patients presented with PE, 7 (78%) of these had elevated APACHE-II mortality risk-score, requiring mechanical ventilation. At admission, PE patients showed signs of systemic and cardiac inflammation in NMR and impaired cardiac function as detected by transthoracic echocardiography (TTE), whereas parameters of myocardial injury e.g. high sensitive troponin-t (hs-TnT) were not yet increased. During the course of disease, hs-TnT rose in 8 of the PE-patients above 16 ng/l, 7 had to undergo ventilatory therapy and 4 of them died. FACS at admission showed in PE patients elevated frequencies of CD3+CD8+ T cells among all CD3+ T-cells, and lower frequencies of Tregs and CD14+HLA-DR+-monocytes. A high CD8/Treg/monocyte ratio predicted a severe disease course in PE patients, and was associated with high serum levels of antiviral cytokines. By contrast, patients without PE and PE patients with a low CD8/Treg/monocyte ratio neither had to be intubated, nor died. CONCLUSIONS: PE predicts cardiac injury in COVID-19 patients. Therefore, TTE should be performed at admission. Immunological parameters for dysfunctional antiviral immunity, such as the CD8/Treg/monocyte ratio used here, supports risk assessment by predicting poor prognosis.