Differences in hub and spoke vascular units practice during the novel Coronavirus-19 (COVID-19) outbreak in Lombardy, Italy

Background: To highlight differences in clinical practice among referral (hub, HH) or satellite (spoke, SH) hospital vascular surgery units (VSUs) in Lombardy, during the COVID-19 pandemic "phase 1" period (March 8 - May 3, 2020). Methods: The Vascular Surgery Group of Regione Lombardia Register, a real-word, multicenter, retrospective register was interrogated. All patients admitted with vascular disease were included. Patients' data on demographics, COVID-19 positivity, comorbidities and outcomes were extrapolated. Two cohorts were obtained: patients admitted to HH or SH. Primary endpoint was 30-day mortality rate. Secondary outcomes were 30-day complications and amputation (in case of peripheral artery disease [PAD]) rates. Univariate and multivariate analysis were used to compare HH and SH groups and predictors of poor outcomes. Results: During the study period, 659 vascular patients in 4 HH and 27 SH were analyzed. Among these, 321 (48.7%) were admitted to a HH. No difference in COVID-19 positive patients was described (21.7% in HH vs. 15.9% in SH; P=0.058). After 30 days from intervention, HH and SH experienced similar mortality and no-intervention-related complication rate (12.1% vs. 10.0%; P=0.427 and 10.3% vs. 8.3%; P=0.377, respectively). Conversely, in HH postoperative complications were higher (23.4% vs. 16.9%, P=0.038) and amputations in patients treated for PAD were lower (10.8% vs. 26.8%; P<0.001) than in SH. Multivariate analysis demonstrated in both cohorts COVID-19-related pneumonia as independent predictor of death and postoperative complications, while age only for death. Conclusions: HH and SH ensured stackable results in patients with vascular disease during COVID-19 "phase 1." Despite this, poor outcomes were observed in both HH and SH cohorts, due to COVID-19 infection and its related pneumonia.