Data emerging from the general population suggests that COVID-19 is essentially an endothelial disease, with possible deleterious long-term effects that are currently incompletely understood. Therefore, our aim is to assess the CV risk in a CKD, dialysis and KTx population, following SARS-CoV-2 infection, by determining the long-term impact of this disease on CV and renal outcomes in the aforementioned population as compared to a control group of matched patients (see Figure 1).
Objectives
The objectives of this observational study are to determine:
-
the feasibility of flow mediated dilation (FMD), bioimpedance spectroscopy (BIS) fluid assessment, lung ultrasound (LUS) and pulse wave velocity (PWV) measurement in CKD patients following COVID-19 and matched CKD control-patients without a history of previous SARS-CoV-2 infection;
-
the long-term impact of the COVID-19 on markers of CV risk and ED in patients with CKD and KTx on a composite CV outcome (time to first non-fatal myocardial infarction, non-fatal stroke, hospitalization for heart failure or CV death) and on all-cause mortality;
-
the long-term impact of the COVID-19 on markers of CV risk and ED in patients with CKD and KTx on a composite renal outcome: doubling of creatinine or a 40% decline in eGFR or dialysis initiation.
Study design
This observational cohort study will include CKD (stage 3 to 5), dialysis and KTx patients from dialysis unit’s auxiliary to Dr. C.I. Parhon University Hospital, Iasi, Romania, diagnosed with COVID-19 according to the interim guidelines of the WHO [28] using the reverse transcriptase polymerase chain reaction (RT-PCR) assay from nasal or throat swab. Patients from North-East of Romania with a documented history of SARS-CoV-2 will be recruited into the CARDIO SCARS IN CKD observational cohort study. All participants must have recovered from acute illness due to SARS-CoV-2 virus infection.
Study population
We aim to enrol 250 patients, divided into two groups with minimum125 patients per group: COVID group and non-COVID group. Both groups will be monitored at 6, 12 and 24 months since the first procedure visit, defined as the baseline.
Inclusion criteria:
- Age>18 years;
- Patients with CKD stage 3-5, including dialysis or KTx with confirmed COVID-19, at minimum 2 weeks after the confirmed test;
- Age, sex and kidney disease (CKD stage 3-5, dialysis or KTx) matched patients without confirmed SARS-CoV-2 infection.
Exclusion criteria:
- Prior diagnosis of pulmonary fibrosis, pneumectomy or massive pleural effusion;
- Active malignancies;
- Pregnancy;
- Active systemic infections (due to difficulties in the interpretation of nonspecific inflammation biomarkers in this type of patients);
- Congenital heart disease.
Approval
All procedures performed in this study were in accordance with the ethics standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments. This study was approved by the Ethical Committee of Grigore T. Popa University of Medicine and Pharmacy of Iasi (no. 110/2021). The enrolled patients will receive a written informed consent approved by the Ethical Committee, that describes the nature of the trial, aims and expected advantages, as well as possible risks, and all study participants will provide signed consent prior to enrolment.
Screening and enrolment
All study procedures (as pointed in Table 1), including screening and enrolment, will be conducted by trained personnel with backgrounds in cardiology, nephrology, internal medicine and medical science. We will recruit participants from the investigators’ clinic patient panel at Dr CI Parhon Clinical Hospital of Iasi and dialysis units from Iasi. Investigators will also partner with other providers from nearby hospitals and/or dialysis centres for enrolment. We will approach participants during routine clinic visits. For retention, we will leverage the electronic medical record to track hospitalizations and scheduled clinic visits during the study period. All participants will first undergo a brief screening discussion, via telephone or in person, to determine eligibility and interest. Participants will be queried on their health history including the presence of other major medical illnesses, to ensure that no exclusion criteria are present. If eligible, participants will be invited to participate in a 1-hour baseline assessment, when each participant will undertake a detailed interview in order to summarize the patient datasheet, further included into the trial database. During the baseline assessment, informed consent will be presented by the study staff including a description and timing of the study procedures, potential risks and benefits of study involvement, rights to withdraw from the study, and details regarding protections against study risks. All participants will receive a copy of their signed informed consent form.
After the consent process, patients will undergo the study interventions as detailed below. At the completion of the baseline intervention, the patients will be scheduled for their second intervention session approximately 6 months later. Participants will be informed that they will continue to receive their usual medical care. After each intervention visit, the patients will receive a copy of their records, data that will be available to their physician if needed.
Table 1
Study procedures flowchart
Procedures/Timepoint
|
|
Study interventions
|
|
Enrolment
|
Baseline
|
6 months
|
12 months
|
24 months
|
Enrolment
|
Eligibility screen
|
X
|
|
|
|
|
Contact information
|
X
|
|
|
|
|
Informed consent
|
X
|
|
|
|
|
Interventions
|
FMD
|
|
X
|
X
|
X
|
X
|
Arterial stiffness
|
|
X
|
X
|
X
|
X
|
Assessment of intima media thickness
|
|
X
|
X
|
X
|
X
|
Echocardiography
|
|
X
|
X
|
X
|
X
|
LUS
|
|
X
|
X
|
X
|
X
|
BIS
|
|
X
|
X
|
X
|
X
|
Blood collection
|
|
X
|
X
|
X
|
X
|
Assessments
|
Clinical data
|
X
|
X
|
X
|
X
|
X
|
IL1, IL6, VCAM-1, endoglin, NO and ADMA
|
|
X
|
X
|
X
|
X
|
CV risk
|
|
|
X
|
X
|
X
|
Mortality rate
|
|
|
|
|
X
|
Renal outcome
|
|
|
X
|
X
|
X
|
ED
|
|
|
|
|
X
|
Study interventions
All the proposed performed procedures are described in Table 2 with a special attention on the used protocol and the obtained result.
Table 2
Protocol for the study procedures
Procedure
|
Protocol description
|
FMD
|
- use of Philips CX50 Ultrasound System with a 12-Mhz probe;
- the vasoactive medications removal for 24 h before the procedure;
- patient in supine position for at least 15 min before the examination;
- the right arm will be immobilized in the extended position for the brachial artery 2-4 cm above the antecubital fossa recording; the contralateral arm will be used if an arteriovenous fistula is present;
- 3 adjacent measurements of end-diastolic brachial artery diameter will be made from single 2D frames;
- the cuff will be inflated up to 50 mmHg higher value of systolic blood pressure and kept this way for 5 minutes;
- the maximum FMD diameters will be analysed from the average of the 3 consecutive maximum diameter measurements, and 1 minute after the cuff will be deflated;
- the FMD will be calculated as the percentage change in diameter compared with baseline resting diameters, in agreement with the criteria set by the International Brachial Artery Reactivity Task Force.
|
Arterial stiffness
|
- applanation tonometry using SphygmoCorTM; PWV Inc., Westmead, Sydney, Australia;
- the patient will be recumbent 10 minutes before the measures;
- measurements: sequentially pulse of the carotid and femoral, the transit time from the R-wave of the simultaneously acquired electrocardiogram to the foot of the carotid and femoral pulse, and the difference acquired electrocardiogram to the foot of the carotid and femoral pulse;
- the carotid-femoral PWV will be calculated from the difference between these 2 transit times divided by distances measured from the body surface (arterial path length).
|
IMT
|
- Philips CX50 Ultrasound System with a 12 MHz probe;
- high-resolution B-mode ultrasound of the common carotid arteries with scanning of the longitudinal axis until the bifurcation and of the transversal axis will be performed;
- two longitudinal measurements will be obtained for each carotid artery, by rotating the vessels at 180o increments along their axis;
- IMT will be measured at 1 cm proximal to the bifurcation on each side.
|
Echocardiography
|
- according to the American Society of Echocardiography recommendations by an observer unaware of the LUS and bioimpedance results;
- measurements: cardiac anatomy (e.g. volumes, geometry, mass) and function (e.g. left ventricular function, valvular function, right ventricular function, and pulmonary artery pressure);
- in patients with adequate acoustic windows, both left ventricular global longitudinal strain (LVGLS) and right ventricular free wall strain (RVFWS) will be calculated.
|
LUS
|
- patient in the supine position;
- measurements of the anterior and lateral chest on both sides of the chest, from the second to the fourth (on the right side to the fifth) intercostal spaces, at parasternal to mid-axillary lines;
- B-lines will be recorded in each intercostal space and were defined as a hyperechoic, coherent US bundle at narrow basis going from the transducer to the limit of the screen; - B-lines starting from the pleural line can be either localized or scattered to the whole lung and be present as isolated or multiple artifacts;
- the sum of B-lines produces a score reflecting the extent of lung water accumulation (0 being no detectable B-line).
|
BIS
|
- portable whole-body multi-frequency bioimpedance analysis device (BCM®Body Composition Monitor – Fresenius Medical Care D GmbH);
- electrodes will be attached to the patient’s forearm and ipsilateral ankle, with the patient in a supine position;
- measurements: body resistance and reactance to electrical currents of 50 discrete frequencies, ranging between 5 and 1000 kHz;
- calculations: ECW, ICW and TBW, to determine the amount of fluid overload;
- AFO is defined as the difference between the expected patient’s ECW under normal physiological conditions and the actual ECW, whereas RFO is defined as the absolute fluid overload AFO to ECW ratio.
|
Blood collection for biomarker evaluation
|
- whole blood will be collected in gel & clot activator tubes (minimum 3.5 mL tube) at each intervention visit for each patient;
- serum will be collected by centrifugation and frozen in aliquots at -80° C until further analysis;
- IL1, IL6, VCAM-1, endoglin, NO and ADMA in serum samples will analysed by specific enzyme linked immunosorbent assay (ELISA) kits on Biochrom EZ Read 400 Microplate Reader.
|
Data collection and follow-up
Data will be collected on paper-based forms and in a secure electronic database for further analysis.
Clinical data
Personal data (age, sex, height); CV risk factors (smoking, alcohol use, weight, body mass index); comorbidities (diabetes, hypertension, coronary artery disease, heart failure etc); physical examination (blood pressure, heart rate, crackles, pedal edema etc); type of renal disease; renal function (urea, creatinine, proteinuria, etc); medication; inflammation evaluation: CRP; complete blood count will be collected.
For the dialysis population: dialysis vintage and for the transplantation population: dialysis vintage before transplantation; date of transplantation, type (living or cadaveric donor), mismatch number, type of induction therapy; type of chronic immunosuppression therapy, will be also collected. Supplementary, for the COVID arm, we will assess also the severity of the infection, administered treatment, use of oxygen therapy, vaccination status.
Outcome data
The primary outcomes of this study will be all-cause mortality rate, a composite CV outcome (time to first non-fatal myocardial infarction, non-fatal stroke, and hospitalization for heart failure or CV death) and long-term impact of the COVID-19 on markers of CV risk and ED in all included patients.
Secondary outcomes are defined as a composite of renal outcome: doubling of creatinine or a 40% decline in eGFR or dialysis initiation in CKD or KTx patients.
Strategies to ensure adequate enrolment and protocol compliance
Report forms will be uploaded into a secure database in a timely manner. This will allow periodical checks for enrolment rates, data accuracy and protocol compliance.
Statistical analysis
The statistical analyses will be performed using the SPSS for Windows, version 19.0.1, R (version 3.1.2) package for statistical analysis and STATA 13. Non-normally distributed variables will be expressed as median with interquartile range and normally distributed variables as mean ± SD, as appropriate. Between-group comparisons will be assessed for nominal variables with the Chi-square test, and by Kruskal-Wallis test or one-way ANOVA for the rest of the variables. In order to comply with the assumptions for regression analysis, logarithmic conversion will be performed for non-normally distributed variables. Pearson correlation coefficient will be used to determine correlations between variables. Stepwise multivariate regression analysis including all univariate associates (p<0.05) will be used to assess the independent associations between variables. Survival and time-to-event analysis of outcomes will be performed using Kaplan-Meier cumulative survival plots and Cox proportional hazards model, including adjustment for potential confounding factors. In the multivariate Cox models, we will adjust for all variables that will be correlated to the study outcomes with P<0.05 at univariate Cox analyses.
Sample size power calculation
We assume that including 125 patients in each group will provide us enough statistical power to adjust for all possible confounders. Our assumption is based on a 20% risk of mortality in patients with ESKD as reported by the preliminary analysis of ERACODA dataset.