Keywords
COVID-19 - venous thromboembolism - bleeding - thromboprophylaxis
Introduction
After the diffusion of the acute respiratory illnesses caused by severe acquired respiratory
syndrome coronavirus-2 (SARS-CoV-2) in China, Italy was the first country severely
infected by the pandemic, with a widespread diffusion in Northern Italy.[1] The virus causes typical severe interstitial pneumonia, but several extrapulmonary
complications have also been reported. In particular, COVID-19 may predispose to both
venous and arterial thromboembolic diseases due to excessive inflammation, hypoxia,
and immobilization. Moreover, COVID-19-associated coagulopathy has been described
that may further increase the thrombotic risk.[2]
[3]
[4] In COVID-19 patients, the presence of strong inflammatory markers, endothelial dysfunction,
platelet activation, and hypercoagulability has been described.[5]
[6] The incidence of venous thromboembolism (VTE) was found to be elevated among patients
admitted to intensive care units (ICUs), in whom 31% of cases were complicated by
thrombotic events, mainly VTE.[3]
[7] Instead, among patients admitted to ordinary wards, the incidence of thrombotic
complications was lower, ranging from 5.8 to 9.2%.[7]
[8] In particular, the incidence was 6.6% among patients admitted to ordinary wards
and systematically treated with thromboprophylaxis.[8]
The aim of our study was to evaluate the incidence and the characteristics of the
thrombotic complications recorded in patients admitted to ordinary wards and included
in the Italian multicenter START-COVID-19 Register in the first wave of the pandemic
during the spring of 2020.
Methods
The START-COVID-19 Register started in May 2020 after the widespread of the COVID-19
pandemic in the frame of the START Register (NCT 02219984).[9] This is a retrospective, observational, nationwide, multicenter register aimed to
collect data on the clinical characteristics, laboratory findings, and drugs employed
from patients infected by COVID-19, hospitalized in ordinary wards. Patients requiring
ICU admission were excluded from the study. The registry was approved by the ethical
committee of the Institution of the Coordinating Member (Azienda Ospedaliero-Universitaria,
Policlinico S. Orsola-Malpighi, Bologna, Italy) and by all ethical committees of participating
centers. All procedures were in accordance with the ethical standards of the institutional
and/or national research committee and with the 1964 Helsinki declaration and its
later amendments or comparable ethical standards. All patients enrolled in the study
read and signed the informed consent. Thirty-one hospitals throughout Italy participated
in this data collection. Details of data collection have been reported in a previous
study.[10] The registry is aimed to record local practice; therefore, no specific tests or
treatments were mandated by the study protocol. All patients underwent nasopharyngeal
and oropharyngeal swab sampling on admission, and the presence of COVID-19 infection
was detected by the polymerase chain reaction method. A dedicated web-based case report
form (e-CRF) obtained with “electronic data capture” system, based on the “Research
Electronic Data Capture” online platform (REDCap, produced and distributed by Vanderbilt
University and “REDCap Consortium”)[11] was used. The e-CRF collected demographic data, clinical data related to associated
diseases, symptoms at admission, and type of treatment. The entity of associated comorbidity
was measured using the Charlson comorbidity index.[12]
VTE prevention strategies were defined as prophylactic when enoxaparin 4,000 to 6,000
U od, fondaparinux 2.5mg od, nadroparin 2,850 to 3,800 to 5,700 U od, or unfractionated
heparin (UFH) 5,000 U bid were used. Treatment was defined subtherapeutic/therapeutic
when enoxaparin 4,000 U bid, enoxaparin 6,000 U bid, enoxaparin 8,000 U bid, fondaparinux
5mg to 7.5mg od, or nadroparin 3,800 U bid or 5,600 U bid, or UFH 12.500 U bid were
used. Patients were followed-up during hospital stay, the follow-up ended when the
patients were discharged, transferred to ICU, or died. The outcome was defined as
being favorable when the patient was discharged, and severe when the patient was transferred
to ICU or died. Thrombotic and bleeding events occurring during follow-up were recorded.
Objective confirmation of thrombotic events was requested. The index event was objectively
confirmed by compression ultrasonography, ventilation-perfusion lung scan, or computed
tomographic pulmonary angiography. Major bleeding (MB) events were defined according
to the International Society of Thrombosis and Haemostasis.[13] Clinically relevant nonmajor bleeding (CRNMB) events were defined as those events
that are not major but require any kind of medical intervention.[14]
Statistical Analysis
Descriptive analysis was performed. Continuous variables were expressed as median
with interquartile range (IQR) or as mean plus or minus standard deviation. Categorical
variables were expressed as frequencies and percentages. Preliminary statistical analysis
was performed using Wilcoxon signed-rank test (continuous variables) or Fisher exact
test (categorical data). A p-value <0.05 was considered statistically significant.
We used the SPSS version 26 software (SPSS Inc, Chicago, IL, United States) for Windows
for data processing.
Results
Patients
From March 1st and June 30th 2020, 1,135 patients hospitalized for COVID-19 infection
were included in the START-COVID-19 Register; 1,091 patients hospitalized in ordinary
wards were included in the study, 653 being males (59.9%) with a median age of 71
years (IQR 59–82 years). Characteristics of patients have been previously described.[10] In brief, hypertension was present in 570 (52.2%) patients, the median Charlson's
index of the cohort was 3 (range 2–5), and 406 (37.2%) patients had no associated
comorbidities. At admission, fever was present in 796 patients (73.0%), dyspnea in
581 (53.3%), and cough in 450 (41.2%).
Thrombotic Complications
During the observation, two (0.2%) patients had acute coronary syndrome episodes and
1 patients (0.1%) had stroke; no other arterial thrombotic events were recorded. Fifty-nine
patients had VTE (5.4%), 18 (30.5%) patients had deep vein thrombosis (DVT), 39 (66.1%)
patients had pulmonary embolism (PE), and 2 (3.4%) patients had DVT+PE. Two patients
(0.2%) had superficial vein thrombosis ([Table 1]). Among patients with DVT, eight (44.4%) were isolated distal DVT and two cases
were jugular thrombosis. Among patients with PE, seven (17.9%) events were limited
to subsegmental arteries. No fatal PE was recorded. PE was diagnosed by CT angiography
in 25 cases and by CT scan in 9 cases, and no information was available for 7 cases.
Table 1
Thrombotic events occurred during follow-up
|
N (%)
|
|
Venous thromboembolism
|
59 (5.4)
|
|
Deep vein thrombosis
|
18 (30.5)
|
|
Proxymal
|
10 (55.6)
|
|
Isolated distal
|
8 (44.4)
|
|
Jugular vein thrombosis
|
2 (5.5)
|
|
Pulmonary embolism
|
39 (66.1)
|
|
Principal artery
|
8 (20.5)
|
|
Segmentary artery
|
22 (56.4)
|
|
Subsegmentary artery
|
7 (17.9)
|
|
Not available
|
2 (5.1)
|
|
Deep vein thrombosis+Pulmonary embolism
|
2 (3.4)
|
|
Superficial vein thrombosis
|
2 (0.2)
|
|
Stroke
|
1 (0.1)
|
|
Acute coronary syndrome
|
2 (0.2)
|
Characteristics of patients with VTE are reported in [Table 2], they presented on the whole a significantly lower number of comorbidities with
respect to patients without VTE, even if the median Charlson comorbidity index was
similar to patients without VTE. Instead, among VTE patients, median D-dimer levels
were significantly higher. The mortality rate was low among patients who had VTE during
hospital stay (2 out of 59 patients, 3.4%) with respect to patients without VTE (198
out of 1,032 patients, 19.2%).
Table 2
Characteristics of patients with and without venous thromboembolism
|
No. of patients with VTE
|
No. of patients without VTE
|
p-Value
|
|
Patients
|
59
|
1,032
|
|
|
Males
|
37 (62.7)
|
616 (59.7)
|
0.7
|
|
Median age (IQR), years
|
69 (58–79)
|
71 (59–82)
|
0.6
|
|
Body mass index median (IQR)
|
26.8 (25.2–30.1)
|
26.0 (24.0–29.1)
|
0.3
|
|
Hypertension
|
20 (33.9)
|
550 (53.3)
|
0.005
|
|
Atrial fibrillation
|
2 (3.4)
|
81 (8.0)
|
0.3
|
|
Venous thromboembolism
|
3 (5.1)
|
33 (3.3)
|
0.4
|
|
Coronary artery disease
|
3 (5.1)
|
107 (10.5)
|
0.3
|
|
Heart failure
|
–
|
22 (2.1)
|
–
|
|
Peripheral arterial disease
|
–
|
16 (1.6)
|
–
|
|
Cerebrovascular disease
|
2 (3.4)
|
63 (6.1)
|
0.5
|
|
Neurological disease
|
7 (11.9)
|
138 (13.4)
|
0.8
|
|
Chronic obstructive pulmonary disease
|
4 (6.8)
|
108 (10.5)
|
0.5
|
|
Rheumatologic disease
|
–
|
21 (2.0)
|
–
|
|
Diabetes mellitus
|
12 (20.3)
|
178 (17.2)
|
0.6
|
|
Cancer
|
4 (6.8)
|
137 (13.3)
|
0.2
|
|
Renal failure (eGFR<30mL/min)[a]
|
4 (14.8)
|
92 (14.7)
|
1.0
|
|
Charlson score, median (IQR)
|
3 (2–4)
|
3 (2–5)
|
0.3
|
|
No comorbidities
|
34 (57.6)
|
372 (36.3)
|
0.001
|
|
Median D-dimer (mg/dL) (IQR)
|
1,668 (505–4,385)
|
779 (407–1,611)
|
0.03
|
|
Prothrombin time ratio, median (range)
|
1.2 (1.1–1.3)
|
1.1 (1.0–1.2)
|
0.1
|
|
Thromboprophylaxis
|
45 (76.3)
|
724 (70.1)
|
0.4
|
Abbreviations: eGFR, estimated glomerular filtration rate; IQR, interquartile range;
VTE, venous thromboembolism.
a Available for 653 patients.
At the time of admission, 70.5% of patients of the entire cohort received thromboprophylaxis,
mainly with prophylactic doses of enoxaparin. The percentage of treatment was similar
among patients who develop and patients who did not develop VTE (p-value=0.4).
Bleeding Complications
During hospital stay, nine (1.2%) patients had MB events and nine (1.2%) patients
CRNMB events. All bleeding events occurred among patients treated with antithrombotic
drugs. MBs and CRNMBs occurred more frequently among patients treated with subtherapeutic/therapeutic
dosage with respect to patients treated with prophylactic dosage (5 [3.1%] and 6 [3.7%]
vs. 4 [0.7%] and 3 [0.5%], respectively).
Discussion
The principal finding of our study is the confirmation of the rate of thrombotic events
reported among patients admitted to ordinary wards for COVID-19 infection. Our results
are consistent with those reported by other authors in hospitalized medical patients
who are not critically ill,[15] frequency ranging from 5.8 to 9.2%.[7]
[8] In particular, in an Italian single-center retrospective cohort study, the proportion
of COVID-19 patients with VTE was found to be 6.6% in ward patients. The thrombotic
events reported are mainly VTE, in particular PE. Our data are in keeping with these
findings. In our cohort, 66.1% of VTE events were PE, with a large number of episodes
confined to segmental and subsegmental arteries, whereas one-fifth of the episodes
involved the main or lobar arteries. None of the events was fatal. Isolated DVT was
present in 30% of patients with VTE, and 8 out of 18 (44.4%) DVT cases were limited
to the distal veins, this frequency being consistent with that found by other authors[7]
[16] as was that of PE and overall DVT.[3]
[8] The mortality rate of VTE patients was impressively lower with respect to that recorded
among patients who did not develop VTE during the hospital stay. This unexpected result
could be explained by the lower number of comorbidities detected among this group
of patients. As a matter of fact, the number of total comorbidities is significantly
lower among patients with VTE with respect to patients without, and a trend of lower
incidence of diseases associated with higher mortality (coronary artery disease, atrial
fibrillation, heart failure, peripheral obstructive arterial disease, cerebrovascular
disease, and cancer) is detected among patients without VTE.
The high prevalence of isolated PE (66.1%) found in our cohort is somewhat surprising,
as it is in contrast with approximately 20% that was reported in different cohorts
of VTE patients without COVID-19 infection.[17]
[18] We speculate that pulmonary vessel occlusions that are seen in COVID-19 patients
are due to the development of local thrombi rather than arising from peripheral veins.[19]
A huge number of patients who require hospitalization in the widespread of the pandemic
end up limiting the diagnosis of VTE, in particular in those with few or no symptoms.
Whenever a systematic leg veins ultrasonography has been performed, a relevant rate
of (mainly) asymptomatic episodes has been reported.[20] Therefore, we cannot exclude that an underdiagnosis of VTE in our patients has occurred.
In our cohort, 70.5% of patients received thromboprophylaxis, in the great majority
enoxaparin at prophylactic dosage. We confirmed the presence of COVID-19-associated
coagulopathy, with elevated median D-dimer levels, higher levels among patients suffering
from thrombotic complications. The role of heparin treatment in reducing mortality
has been reported by several studies; on the contrary, a clear role in the thromboembolism
prevention has not been demonstrated.
We acknowledge the limitations of our study. First, it is a retrospective observational
study, and no standardized diagnostic procedure for the detection of thrombotic events
was indicated by the study protocol. The severity of patients enrolled, as indicated
by the elevated number of patients with fatal outcomes, may have determined underdiagnosis
of thrombotic events particularly in the case of pauci- or asymptomatic episodes.
The strength of the study lies in the multicentric design and the accuracy and completeness
of follow-up for all patients enrolled.
In conclusion, we confirmed that patients admitted to ordinary wards for COVID-19
infection are at high risk for thromboembolic events. VTE recorded among these patients
is mainly isolated PE, differently from the incidence of isolated PE commonly observed
in the cohorts of VTE patients without COVID-19 infection, suggesting a peculiar characteristic
of VTE in these patients.
List of Participating Centers
List of Participating Centers
-
Daniela Poli, Rossella Marcucci, SOD Malattie Aterotrombotiche, Azienda Ospedaliero
Universitaria-Careggi, Firenze
-
Walter Ageno, Giovanna Colombo, UOSD Degenza Breve e Internistica, Centro trombosi
Ospedale di Circolo, Varese
-
Chiara Ambaglio, UOSD SIMT Servizio di Immunoematologia e Medicina Trasfusionale,
Ospedale di Treviglio – Caravaggio, ASST Bergamo Ovest, Bergamo
-
Guido Arpaia, U.O. Medicina Interna Carate Brianza ASST-Vimercate
-
Giovanni Barillari, SOS di Dipartimento “Malattie Emorragiche e Trombotiche, ASUGI,
Udine
-
Giuseppina Bitti, Giuseppe Pio Martino Medicina Interna Ospedale Civile di Fermo
-
Eugenio Bucherini, Dipartimento Cardiovascolare - Azienda USL di Ravenna, Faenza
-
Antonio Chistolini, Alessandra Serrao, Dipartimento di Biotecnologie Cellulari ed
Ematologia, Azienda Ospedaliero Universitaria Policlinico Umberto I, Roma
-
Egidio De Gaudenzi, SOC Medicina Interna Ospedale San Biagio – Domodossola
-
Valeria De Micheli, Ambulatorio Emostasi - Azienda Ospedaliera Di Lecco
-
Anna Falanga, Teresa Lerede, Luca Barcella, Laura Russo, USC SIMT, Centro Emostasi
e Trombosi, Ospedale Papa Giovanni XXIII, Bergamo
-
Vittorio Fregoni, U.O.C. Medicina Generale, ASST Valtellina e Alto Lario Ospedale
di Sondalo.
-
Silvia Galliazzo, UOC Medicina Generale, Ospedale San Valentino, Montebelluna (TV)
-
Alberto Gandolfo, Valentina Trapletti, Gianni Biolo, Clinica Medica, Azienda Sanitaria
Universitaria Giuliano Isontina (ASU GI) –Ospedale di Cattinara, Trieste
-
Giorgio Ghigliotti, Clinica Delle Malattie Dell'apparato Cardiovascolare Policlinico
San Martino Genova
-
Elisa Grifoni, Medicina Interna 2, Ospedale San Giuseppe, Empoli (Fi)
-
Egidio Imbalzano, UOC Medicina Interna, Policlinico di Messina
-
Gianfranco Lessiani, Unità Angiologica, Dipartimento di Medicina e Geriatria, Ospedale
“Villa Serena,” Città Sant'Angelo, Pescara
-
Giuliana Martini, Sara Merelli, Nicola Portesi Centro Emostasi, Spedali Civili Di
Brescia,
-
Franco Mastroianni, Giovanni Larizza, Covid Unit Subintensiva, EE Ospedale Generale
F.Miulli, Acquaviva delle Fonti (Ba)
-
Serena Panarello, Chiara Fioravanti, SC Medicina Interna, EO Galliera, Genova
-
Simona Pedrini, Servizio di Laboratorio, Istituto Ospedaliero Fondazione Poliambulanza,
Brescia
-
Raffaele Pesavento, Davide Ceccato, UO Clinica Medica 3 AOU Padova
-
Pasquale Pignatelli, Daniele Pastori, I Clinica Medica, Medicina Interna Covid e Centro
Trombosi
-
Sapienza, Università di Roma
-
Paola Preti, Centro Emostasi e Trombosi, IRCCS Fondazione Policlinico S. Matteo, Pavia
-
Girolamo Sala, Fabrizio Foieni, Michela Provisone, Ospedale di Circolo Busto Arsizio
(Va)
-
Luca Sarti, Antonella Caronna, Paolo Vita, Medicina Interna e Area Critica, Ospedale
di Baggiovara (Mo)
-
Federico Simonetti, Ilaria Bertaggia, UOC Ematologia Aziendale – Ospedale Versilia
–Lido di Camaiore (Lucca)
-
Piera Sivera, Carmen Fava, S.C.D.U. Ematologia e terapie cellulari, AO Ordine Mauriziano
Umberto 1° Torino
-
Adriana Visonà, Beniamino Zalunardo, UOC Angiologia, Ospedale San Giacomo Apostolo,
Castelfranco Veneto (Treviso)
-
Sabina Villalta, UOC Medicina Generale, Ospedale San Giacomo Apostolo, Castelfranco
Veneto (Treviso)
