Evaluation of cardiac function in patients with pemphigus vulgaris before and after rituximab infusion

Background Pemphigus is an autoimmune blistering disease of the skin and mucous membranes. Immunosuppressive drugs such as rituximab have been used as treatment of this possibly fatal disease. Rituximab infusion is associated with multiple complications such as cardiac side effects. Global strain measurement (GLS) has emerged as an important index of cardiac performance that adds incremental predictive value to standard measures such as the LVEF. Method This cross-sectional and prospective study was performed on patients with pemphigus vulgaris. To evaluate cardiac function, global longitudinal strain estimation, echocardiography


Introduction
Pemphigus vulgaris is an autoimmune blistering disease of the skin and mucous membranes [1].Traditionally, steroids have been the mainstay of treatment, usually used at high doses initially to control the disease and then in conjunction with a steroid-sparing agent for maintenance.Because of the side effects associated with long-term systemic corticosteroids such as hypertension, diabetes mellitus, osteoporosis, and ocular complications, recent research in pemphigus has been directed for nding the optimal steroid-sparing agent [2].Rituximab (RTX) is a monoclonal anti-CD20 antibody that is a very effective therapy for treatment of pemphigus, even in cases refractory to standard immunosuppressive therapy.This agent was approved by FDA for the treatment of pemphigus vulgaris in 2018 [3].Rituximab is an anti-CD20 chimeric antibody that selectively targets B lymphocytes [4].Many dermatologists currently use rituximab, as rst-or second-line therapy due to evidence from 2017 suggesting better outcomes when rituximab is used as a rst-line agent [5,6].Despite the high e ciency of this drug, it has several adverse effects such as allergic reactions, infections, and deep vein thrombosis of the leg and pelvis [7].Previous studies have reported a number of cardiac adverse effects of rituximab, arrhythmogenic effects being the most frequent one [8][9][10].
Additionally, several studies have revealed the association of auto immune bullous disease (AIBD) with cardiovascular side effects.According to a recent systematic review AIBD was associated with higher incidence rate of diabetes, hypertension, dyslipidemia and heart failure, but was not associated with, stroke,, obesity, arrhythmia, angina, and heart attack [11].Therefore, increased cardiovascular disease screening and prevention strategies are necessary in AIBD regardless of treatment.
Currently, estimation of left ventricular (LV) function performed by echocardiography is the most frequent method to evaluate cardiac function; however, this method is subjective and time-consuming [12].Recently, tissue doppler imaging (TDI) has been recommended as a useful echocardiographic technique to evaluate LV systolic and diastolic function with acceptable accuracy [13].Guidelines recommend using early to late diastolic transmitral ow velocity (E/A) to assess diastolic function, and E to early diastolic mitral annular tissue velocity (E/e') to estimate LV lling pressures [14,15].Global longitudinal strain (GLS) is an inexpensive marker for the estimation of global long-axis systolic function.Global longitudinal strain is a reliable index measured by 2D echocardiography exhibiting the function of subendocardial longitudinally oriented bers, that are susceptible to ischemic injury and wall stress [16].
Consequently, it can re ect anomalous contraction patterns despite seemingly normal LVEF [17] Several studies have shown that alterations in GLS is associated with drug induced cardiac toxicity particularly during cancer treatment [18].However, the results of these studies are inconsistent with regard to the GLS cutoff values and study population [19].
Another bene cial technique is global longitudinal strain (GLS), which has emerged as an important measure of cardiac performance that adds incremental predictive value to standard measures such as the LVEF.According to the current evidence, global strain measurement is bene cial in assessing the effect of cardiotoxic chemotherapies over time [12].This study was designed to evaluate the cardiac effects of rituximab in pemphigus patients.

Patients and methods
This prospective-cross sectional study was conducted on 36 patients with PV who were referred to Shohada Tajrish Hospital dermatology department in Tehran, Iran during 2018-2019, who were eligible for rituximab infusion whether as the rst-line treatment or as a part of their treatment protocol.The study protocol was approved by our institutional ethics committee (IR.SBMU.MSP.REC.1399.345).Adult PV patients with no history of heart disease and non-pregnant patients were included in the study.Diagnosis of the disease was performed by dermatologist based on clinical manifestations, pathology, and direct immuno uorescence studies.
Before admission, medical history was obtained and a complete physical examination was performed.Echocardiography, GLS measurement, ECG examination, and laboratory examinations were done for all our patients and only patients with normal results were candidates for rituximab infusion included in the study [20,21].Rituximab was administered in 4 consecutive weekly infusions with a dosage of 500mg in 500 cc normal saline slow infusion over 4 hours, with premedication of oral acetaminophen 500 mg, chlorphenamine 10 mg IM, and hydrocortisone 100 mg IV [22,23].During infusion, patients were closely monitored by cardiac monitoring and checking their vital signs every 15 minutes.Any new sign or symptom led to drug discontinuation and patient re-evaluation.Two hours after completion of each infusion, all patients underwent ECG examination to asses any ECG alterations.A day after the last infusion in the fourth week, the same cardiologist performed echocardiography and GLS measurements for all patients to compare them with baseline data.Echocardiography including tissue doppler index (E/ è, E/A) and GLS measurement were performed using a GE Vivid T8 ultrasound machine by the same expert cardiologist.The demographic information, such as age and gender, underlying diseases, drug history, echocardiographic, and GLS ndings, were recorded in a standard pre-prepared checklist.Descriptive statistics were reported using frequencies, percentages, and mean ± standard deviation.A normality examination was performed with Shapiro-Wilks.The paired sample T-test was performed to compare parameters before and after rituximab infusion.A Pearson test (r) was applied to measure the correlations between the variables.All analyses were performed using Statistical Package for Social Science (SPSS) version 26 (IBM crop Released 2016, NY, USA) and P value less than 0.05 was considered statistically signi cant.

Result
Thirty-six pemphigus vulgaris patients with a mean age of 47.86 ± 12.02 years were enrolled in this study.
Male to female ratio was 11(30.55%)/25(69.45%).Nineteen (38.9%) patients had at least one comorbidity.The most prevalent comorbidity was hypertension followed by diabetes, and hypothyroidism (Table 1).In this study, 19(52.8%)patients had received infusion for the rst time and 16(47.2%)patients had a previous history of rituximab infusion cycle for treatment of pemphigus, during the last few years.Low-dose oral prednisolone and azathioprine consumption, as maintenance therapy were reported by 22 (61.1%) and 6 (16.6%) patients respectively.One patient reported sore throat and dyspnea, and one patient reported mild chest discomfort during the rst cycle of infusion.These side effects were improved by slowing down the infusion rate and administration of antihistamines.None of the patients had changes in 2 hours ECG examination after the rituximab infusion completion.
In our study, the spearman correlation showed signi cant inverse association between age and LVEF changes (r=-0.378,p-value = 0.023).Correlation between age and PASP changes was signi cantly positive (r = 0.398, p-value = 0.002), but the correlation between age and GLS change was not statistically signi cant.

Discussion
Our study revealed that rituximab may have potential cardiotoxic side effect in pemphigus patients as we observed mean GLS decreased signi cantly after rituximab infusion (p-value = 0.0001).Rituximab an anti-CD20 monoclonal antibody is an effective treatment for pemphigus patients and has recently been recommended as rst-line treatment [24,25].However, it has been associated with a variety of side effects including infusion reactions and cardiac side effects.The majority of currently published reports on cardiac side effects of rituximab have been limited to reported cases of arrhythmias, angina, and ACS in non-pemphigus patients [26].
We did not observe any ECG alteration 2 hours after infusion completion in each cycle, but according to the results of a study conducted by Sheila Aidi et al, on Adverse electrocardiographic effects of rituximab infusion in pemphigus patients, in 2020, the mean corrected QT (QTc) interval, premature atrial contraction (PAC), and premature ventricular contraction (PVC) counts increased signi cantly after rituximab infusion (P value ≤ 0.05) [27].
To our knowledge, no previous study has applied GLS to assess cardiac function after rituximab infusion, but there are reports about using GLS to evaluate cardiac function after other medication (31)(32)(33).A study by Shahidi-Dadras et al showed a statistically signi cant reduction in GLS value after the administration of methylprednisolone pulse therapy in pemphigus patients [28].Several studies have suggested GLS measurement as bene cial marker for evaluation of cardiac function during cancer treatment due to being less operator dependent compared to LV ejection fraction [28,29].This measure is also helpful in identifying subclinical cardiac dysfunction, as Guerra et al, observed that subclinical systolic dysfunction of both LV and RV in myositis can be detected by GLS [30].
A study designed by Cheratato et al, to assess right ventricular systolic function in cancer patients mentioned GLS as a valuable method for identifying subclinical right ventricular dysfunction appearing in the course of cancer treatment [31].Also, there are multiple studies demonstrating GLS measurement would be the ideal strategy to reduce mortality in patients at high risk for developing cardiotoxic wellestablished side effect of several antineoplastic drugs, particularly anthracyclines [32,33].According to the current evidence the relative GLS alteration more than 10-15% is related to subclinical myocardial dysfunction but it is unclear whether this is a sensitive or speci c threshold [19,34].The mean early reduction of GLS was 6.8% compared to pretreatment values.The reduction in GLS was > 10% in 8 patients (22.2% of cases).Long-term follow up is needed to evaluate how GLS change could affect longterm LVEF.
Signi cant reduction of EF was observed a day after the last cycle of rituximab infusion in three patients who had underlying HTN (one female and two males).None of them were symptomatic nor had ECG alterations, but overall analysis showed LVEF change was not statistically signi cant.Our nding is consistent with multiple studies that used echocardiography to examine rituximab cardiotoxicity [35][36][37].In a study conducted by Coi er et al, complications such as grade 3 or 4 cardiac failure or left ventricular dysfunction occurred with the same frequency after the administration of CHOP plus rituximab or CHOP alone.These results suggest that rituximab does not affect cardiac functions [8].Rabinovitz et al examined the cardiotoxicity of rituximab, which was de ned as a decrease in LVEF to < 50% or hospital admission for congestive heart failure.Their study showed rituximab therapy, was not associated with an increased occurrence of cardiotoxicity in cancer patients [36].
Elwazir et al reviewed seven patients with active cardiac sarcoidosis who were treated with rituximab.According to their study, the mean left ventricular ejection fraction increased after rituximab treatment [37].In contrast to these studies, Kanamori et al reported 3 cases of non-Hodgkin's lymphoma patients who were treated with rituximab.These patients experienced a statistically signi cant reduction in ejection fraction after the administration of rituximab, the authors believed that the cardiac side effects were caused by the persistent elevation of TGF-β levels after treatment with rituximab [38].
In our study, mean pulmonary artery systolic pressure was stabilized before and after rituximab infusion which was consistent with the result of the study recorded by Garzanova et al, that assessed changes in the signs of heart involvement in systemic sclerosis patients one year after initiation of rituximab therapy [39].
There are some limitations to our study.First of all the sample size was rather small.We performed thisstudy during COVID-19 pandemic which affected data gathering.Secondly all of our patients received rituximab with dose of 500 mg weekly while the current consensus recommend infusion of 1 gr rituximab 2 weeks apart.The optimal protocol for rituximab administration in PV patients is yet to be investigated.

Conclusion
Our study showed that rituximab may have cardiac side effects in patients with pemphigus vulgaris measured by a decrease in GLS.The interval for follow up should be individualized based on cardiovascular risk factors.According to the wide use of rituximab as rst-line treatment in patients with pemphigus, dermatologists should be aware of possible cardiac complications and monitor their patients for these side effects.The optimal treatment protocol for rituximab is yet to be identi ed.Further studies are recommended to shed light on the exact interaction of rituximab with cardiovascular system Ghalamkarpour participated in data gathering, Zohreh Tehranchinia participated in data gathering , Fahimeh Abdollahimajd participated in data gathering, Hamideh Moravvej participated in data gathering, Reza Robati edited the main manuscript, Nikoo Mozafari edited the manuscript and participated in data gathering , Nastaran Namazi participated in data gathering, Reem Diab documented the data, Zahra Razzaghi help with statistical analysis, Kimia Karimi Toudeshki participated in data gathering, Sahar Dadkhahfar participated in data gathering, proposing the main idea and writing the manuscript , Soheila Nasiri ata gathering, proposing the main idea and writing the manuscript.All authors reviewed the manuscript.

Figure 2 of
Figure 2