Sodium Thiosulfate in Acute Myocardial Infarction

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SUMMARY
In this proof-of-principle trial, the hypothesis was investigated that sodium thiosulfate (STS), a potent antioxidant and hydrogen sulfide donor, reduces reperfusion injury.A total of 373 patients presenting with a first ST-segment elevation myocardial infarction received either 12.5 g STS intravenously or matching placebo at arrival at the hospital and 6 hours later.The primary outcome, infarct size, measured by cardiac magnetic resonance at 4 months after randomization, did not differ between the treatment arms.Secondary outcomes were comparable as well, suggesting no clinical benefit of STS in this population at relatively low risk for large M yocardial infarction is a common cause of disability and death worldwide. 1Infarct size is the major determinant for the future development of heart failure and reduced life expectancy. 2jor progress has been made to limit infarct size, mainly by thrombolysis and primary percutaneous coronary intervention (PCI) in combination with antiplatelet therapy.Despite this progress, death rate, heart failure, and recurrent cardiac events continue to remain substantial in patients presenting with acute myocardial infarction. 3,4[12] Sodium thiosulfate (STS) is a strong antioxidant and anti-inflammatory compound with vasoactive properties. 133][24][25][26] In an earlier dose-escalation pilot study, we demonstrated that STS was well tolerated in patients presenting with an acute coronary syndrome undergoing PCI. 27 this proof-of-principle trial, we tested the hypothesis that STS treatment reduces infarct size in patients presenting with ST-segment elevation myocardial infarction (STEMI).TRIAL OUTCOMES.CMR is the preferred method for the identification of potential benefits associated with new cardioprotective strategies. 29The primary outcome of this trial was infarct size expressed as percentage of LV mass.Infarct size was measured Glucose, mmol/L 5.7 (5.5, 6.
2][33]  The epicardial and endocardial borders were outlined in end-systolic and -diastolic images to measure left ventricular volumes and calculate LVEF.Infarct size was quantified using an automated method (full width at half maximum) with manual correction. 34,35l CMR scans were evaluated by an independent core laboratory (Radboud UMC) using dedicated software (QMass, Medis Suite 3.2.28.0).The core laboratory was blinded to treatment allocation and clinical patient data.All CMR measurements and calculations were performed, and data was locked before unblinding.
STATISTICAL ANALYSIS.This trial was designed as a proof-of-concept study.We considered a relative reduction of 33% in infarct size relevant. 33In the previous GIPS-III trial, the mean infarct size was 9.0% AE 7.9%. 36To have 85% power to detect a 3%  de Koning et al were performed according to a prespecified analysis plan that was finalized before database lock and unblinding.No formal interim analysis took place.
Missing data were not imputed.The primary outcome, infarct size, was analyzed with Beta regression on an intention-to-treat basis.
Treatment allocation, recruiting site, and anterior myocardial infarction were added to the model as fixed variables.The regression coefficient for treatment allocation is the primary outcome and is reported as the (marginal average) difference in infarct size between the STS and placebo group, together with a P value and 95% confidence interval (CI).As described in the design paper, 28 we used Beta regression for the primary analysis because it is the preferred method of analysis for proportional data with a non-normal distribution.Likewise, a Beta regression within the per-protocol population was performed, including all patients who received complete treatment with study medication, without major protocol deviations.Irrespective of the primary outcome reaching statistical significance, prespecified subgroup analyses were performed using regression analyses with a test for interaction for age (below vs above the median), gender, TIMI (Thrombolysis In Myocardial Infarction) flow pre-PCI (#1 vs >1), infarct location (anterior vs nonanterior myocardial infarction), ischemic time (below vs above the median), single vs multivessel disease, and the time from start of study medication to first coronary intervention (below vs above the median).
For analyses of secondary outcomes, when binary, treatment comparisons were performed using the Fisher exact or chi-square test.For continuous outcomes, independent samples Student's t-tests or Mann-Whitney U tests were used, as appropriate.
A 2-sided a of 0.05 was considered statistically significant.Analyses were performed with STATA version 14.0 (StataCorp).

RESULTS
From July 16, 2018, through March 2, 2021, a total of 1,650 patients presenting with suspected STEMI in 1 of the 3 recruiting centers were screened for eligibility (Supplemental Figure 1).A total of 380 patients   1 and 2) and at discharge (Supplemental Table 1).The mean age in the overall population was 62 AE 12 years, and 23.1% of the patients were women.The median time from onset of complaints to wire passage was 141 minutes (Q1, Q3: 102, 177 minutes).Before primary PCI, 371 (99.5%) patients received aspirin, and all patients received a loading dose of a P2Y 12 inhibitors and heparin.TIMI 0 or 1 flow before PCI was observed in 245 (65.7%) patients, and the left anterior descending artery was identified as the culprit lesion in 152 (40.8%).After PCI, a TIMI flow grade 0 or 1 was observed in 14 (3.8%) patients.
PRIMARY OUTCOME.CMR was completed in 238 patients 4 months after randomization (median 4.0 months [Q1, Q3: 3.8, 4.5 months], full range 3.4 to 8.2 months).The primary outcome parameter, infarct size on CMR, could be determined in 116 patients in the STS group and 110 in the placebo group (Supplemental Figure 1).The baseline, procedural, and discharge characteristics were also well balanced between the STS and placebo-treated patients of the CMR population (Supplemental Tables 2 to 4).
Infarct size at 4 months after randomization did not differ between the STS and placebo-treated patients.Mean infarct size in the STS group was 8.0% AE 7.0% and was 8.9% AE 7.4% in the placebo group.The marginal average change in infarct size in the STS group was À0.6%; 95% CI: À2.4% to 1.2%; P ¼ 0.55, compared with participants treated with placebo (Figure 1, Table 3).1.
de Koning et al

PER-PROTOCOL ANALYSIS AND SUBGROUP ANALYSES.
The results of the per-protocol analysis were consistent with the intention to-treat analysis (Supplemental Table 5).The results of the primary endpoint were also consistent across prespecified subgroups (Figure 2).

DISCUSSION
Among patients presenting with STEMI, intravenous STS treatment initiated before primary PCI did not reduce myocardial infarct size compared with placebo.There was also no effect on LVEF.Patients in the STS group were more likely to experience nausea and vomiting than those in the placebo group.
Patients presenting with STEMI are routinely treated with primary PCI to treat myocardial ischemia with reperfusion.Reperfusion to an ischemic area has been associated with cellular injury, which may substantially contribute to the final infarct size. 8,10The current proof-of-concept study was developed to clinically translate the plethora of preclinical studies providing strong mechanistic and functional evidence that STS and H 2 S can substantially reduce Sodium Thiosulfate in Myocardial Infarction reperfusion injury. 14,40[42][43][44] STS has also been shown to be beneficial in several other clinical settings associated with cellular toxicity (eg, cyanide intoxication, calciphylaxis, reduction of cisplatin-related toxicity).In our study, STS induced the known side-effects such as nausea and vomiting, but did not reduce myocardial infarct size.
Several findings may explain the lack of benefit of STS in our patient cohort.First, the final infarct size of our patients was relatively small.This is a consequence of the well-organized STEMI network in the Netherlands with short ischemic time (2-2.5 hours vs 3 hours in other recent studies) [45][46][47] and pretreatment by the ambulance service with a loading dose of a P2Y 12 inhibitor, aspirin, and intravenous heparin.
Moreover, we also included patients with TIMI 2 to 3 flow pre-PCI, because the study treatment was initiated before performing the coronary angiogram to reach therapeutic levels before reperfusion, bearing in mind that early administration of study medication might increase the likelihood of cardioprotection, 48 and that the majority of detrimental effects of ischemia-reperfusion injury already occur during the first moments after reperfusion. 8Potential benefit of STS cannot be excluded in the absence of pretreatment with antiplatelets or in a certain subgroup of patients-eg, those presenting with completely closed arteries for extended time, combined with high Killip class, and large area at risk, who thus are patients with higher probability of possible additional myocardial salvage. 49Also, in setting of low availability or unavailability of primary PCI, resulting in delayed reperfusion, STS might reduce myocardial injury.Second, the required cardioprotective concentrations of STS might be higher than could be achieved in this trial.However, the dosage was based on prior efficacy data in humans and was limited by the known side effects. 20,50,51Furthermore, the amount of STS and H 2 S released in the heart during reperfusion remains unknown.Future substudies in stored blood samples might provide insight in concentrations and effects on oxidative stress and inflammation.Finally, the duration of treatment was limited to the first hours after reperfusion (T 1/2 z 3 hours), whereas reperfusion injury lasts longer. 21,52velopment of oral preparations might enable continued treatment for an extensive period of time, potentially allowing the reported anti-inflammatory, antioxidant, and proangiogenic properties of H 2 S/ STS, to modify outcomes. 25,53Finally, failure to translate preclinical studies into clinical benefit might originate from the absence of comorbidities and comedications in animal models. 49e incidence of adverse side effects, mainly nausea and vomiting, was comparable to STS use in other conditions. 19,20The emetogenic effect of STS did not result in discontinuation of study medication, and the additional use of prophylactic antiemetic agents, as was recommended by the DSMB, appeared to reduce the incidence of nausea and vomiting.Potential effects of antiemetics on cardioprotection could not be ruled out. 54However, the preemptive administration in both treatment groups minimized this potential bias.The change in blood pressure that we observed in both groups after the first dose of study medication was likely caused by administration of vasodilators, required for the radial PCI procedure, because between-group differences were not observed and no change in blood pressure occurred after the second dose of study medication.
STUDY LIMITATIONS.First, partly because of the national COVID-19 pandemic restrictions to visit the hospital for non-essential care and fear of patients to acquire a COVID-19 infection, the actual percentage of patients who underwent randomization who were available for the primary outcome measure was 59% instead of the anticipated 66%.This led to a reduction de Koning et al of statistical power from the desired 85% to the actual 80%.Post-hoc, it seems unlikely that adding w10 more participants to each arm would have substantially modified our findings.Also, the studied number of patients with CMR remains in line with recommendations for the evaluation of cardioprotective strategies. 29Second, our study was also not powered to detect clinical outcomes such as all-cause mortality or hospitalization for heart failure.However, CMRdetermined infarct size has been the recommended primary outcome for early assessment of potential cardioprotective therapies. 29The relevance of our primary outcome is also supported by the reported strong graded response with subsequent mortality and hospitalization for heart failure. 2 We did not take into account area at risk when determining infarct sizes.
However, the comparable percentages of proximal culprit lesions (also within each culprit vessel) in both treatment arms (41%) suggest balanced areas at risk.
Finally, women were under-represented, and very few patients were non-Caucasian.

CONCLUSIONS
We assessed the effect of STS in a proof-of-concept study of patients with STEMI undergoing primary PCI.The administration of STS at time of reperfusion did not lead to a reduction in infarct size.The studied STS dose was not associated with significant adverse events.E-mail: p.vanderharst@umcutrecht.nl.@profpim, @MarieSophiedeK1.Sodium Thiosulfate in Myocardial Infarction

FUNDING SUPPORT AND AUTHOR DISCLOSURES
infarction.(J Am Coll Cardiol Basic Trans Science 2023;8:1285-1294) © 2023 The Authors.Published by Elsevier on behalf of the American College of Cardiology Foundation.This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
TRIAL DESIGN AND OVERSIGHT.GIPS-IV (Groningen Intervention Study for the Preservation of CardiacFunction with STS after STEMI) is an investigatordriven, randomized, controlled, double blind trial conducted in 3 high-volume PCI centers in the Netherlands: University Medical Centre Groningen, Groningen, the Netherlands; University Medical Centre Utrecht, Utrecht, the Netherlands; and Treant Hospital, Emmen, the Netherlands.Details of the trial design have been previously published.28All studyA B B R E V I A T I O N S A N D A C R O N Y M S CK-MB = creatinekinase myocardial band CMR = cardiac magnetic resonance DSMB = data and safety monitoring board H2S = hydrogen sulfide LVEF = left ventricular ejection fraction NT-proBNP = N-terminal pro-B-type natriuretic peptide PCI = percutaneous coronary intervention STEMI = ST-segment elevation myocardial infarction STS = sodium thiosulfate From the a Department of Cardiology, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands; b Department of Cardiology, Division of Heart and Lungs, University Medical Centre Utrecht, Utrecht, the Netherlands; c Department of Cardiology, Treant Hospital, location Scheper, Emmen, the Netherlands; d Department of Methodology and Statistics, Utrecht University, Utrecht, the Netherlands; e Optentia Research Programme, North-West University, Vanderbijlpark Campus, Vanderbijlpark, South Africa; f Department of Radiology, University Medical Centre Utrecht, Utrecht, the Netherlands; g Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA; h University of Groningen, University Medical Centre Groningen, Cognitive Neuroscience Centre, Groningen, the Netherlands; i Department of Pathology and Medical Biology, University of Groningen, University Medical Centre Groningen, Groningen, the Netherlands; and the j Department of Cardiology, Radboud University Medical Centre, Nijmegen, the Netherlands.The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors' institutions and Food and Drug Administration guidelines, including patient consent where appropriate.For more information, visit the Author Center.Manuscript received February 22, 2023; revised manuscript received June 7, 2023, accepted June 8, 2023.de Koning et al J A C C : B A S I C T O T R A N S L A T I O N A L S C I E N C E V O L .8 , N O . 1 0 , 2 0 2 3 Sodium Thiosulfate in Myocardial Infarction O C T O B E R 2 0 2 3 : 1 2 8 5 -1 2 9 4 procedures were in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines.The conduct of the trial was supervised by the trial steering committee.An independent data and safety monitoring board (DSMB) oversaw the safety of the trial.The authors designed and coordinated the trial, oversaw the study conduct and reporting, managed the database, and wrote all drafts of the paper.All of the authors vouch for the accuracy and completeness of the reported data and analyses.The contents of this paper are consistent with the research protocol, which was approved by the ethics committee (Ref.2016.381;Groningen, the Netherlands) and national authority.Before commencing enrollment, the trial was registered in a clinical trial registry under number (NCT02899364).Detailed information about the trial organization is available in Supplemental Appendix.STUDY POPULATION.Adults who presented with a first STEMI were eligible if their symptoms started within 12 hours before presentation and their symptoms were ongoing and/or ST-segment elevation was persistent upon arrival at the cardiac catheterization laboratory.Patients with a history of prior myocardial infarction, coronary artery bypass grafting or cardiomyopathy, a malignancy treated with chemotherapy and/or radiotherapy (chest region), or any condition that did not allow the patient to successfully undergo cardiac magnetic resonance (CMR) or participate in the study were excluded.Details of the inclusion and exclusion criteria are provided in the trial protocol.TRIAL PROCEDURES.The study procedures were designed not to delay primary PCI.Immediately after arrival at the cardiac catheterization laboratory, witnessed oral consent was obtained by the interventional cardiologist, and patients directly received the next-in-sequence randomized kit of either STS 12.5 g or matching placebo.Study medication was dissolved in 250 mL of normal saline and administered intravenously in 20 to 30 minutes before and during PCI.Six hours after the first dose, a second dose of study medication was administered.The rationale behind the timing and dosage of study medication has been previously published. 28Known side effects of STS include nausea, vomiting, and hypotension, 20 which were specifically monitored before and after each dose of study medication.Due to high incidences of nausea and vomiting observed during the execution of the trial, the DSMB recommended to preventively administer antiemetics (metoclopramide 10 mg intravenously) before each dose of study medication.The trial protocol was amended accordingly.During hospitalization, written informed consent was obtained, and creatine kinase MB (CK-MB) was measured to determine enzymatic infarct size.Four months after randomization, participants were scheduled for a hospital visit to obtain CMR and to assess adverse events and N-terminal pro-B-type natriuretic peptide (NT-proBNP).In case a participant declined CMR, adverse events were assessed by telephone.Study medication was produced, randomized, and labelled according to Good Manufacturing Practice by A15 Pharmacy.Randomization was performed in a 1:1 ratio in permuted blocks of 4, with stratification by recruiting site and for anterior vs nonanterior myocardial infarction.The patient, interventional cardiologist, all caregivers, data collectors, and the CMR core laboratory were blinded to treatment allocation.
Secondary outcome parameters included the effect of STS on peak CK-MB during index hospitalization, left ventricular ejection fraction (LVEF) on CMR at 4 months, and NT-proBNP concentration at 4 months follow-up.Clinical events were also assessed up to 4 months after randomization and included all-cause mortality, the combined incidence of major adverse cardiovascular events (cardiovascular death, reinfarction, unscheduled reintervention), stent thrombosis, stroke, implantable cardioverter-defibrillator implantation, and hospitalization for chest pain or heart failure.All potential clinical endpoints were adjudicated by an independent endpoint adjudication committee blinded to treatment allocation.The endpoint definitions are available in Supplemental Methods II.CMR PROTOCOL.All CMR studies were performed on a 3-T clinical MR scanner (multivendor Siemens, Philips), using a phased array cardiac receiver coil.Electrocardiogram-gated balanced steady-state free precession cine images were acquired during repeated breath holds in the standard long-axis views (4-, 3-, and 2-chamber views) and contiguous shortaxis slices covering the entire left ventricle.Using identical slice locations, late gadolinium enhanced images were acquired at least 10 minutes after intravenous administration of a gadolinium-based contrast agent (0.2 mmol/kg) with a single shot inversion recovery gradient-echo pulse sequence.

FIGURE 1
FIGURE 1 Primary and Secondary Outcomes by Allocated Treatment

J
A C C : B A S I C T O T R A N S L A T I O N A L S C I E N C E V O L .8 , N O . 1 0 , 2 0 2 3 de Koning et al O C T O B E R 2 0 2 3 : 1 2 8 5 -1 2 9 4 Sodium Thiosulfate in Myocardial Infarction underwent randomization and received a first dose of study medication.Seven patients withdrew informed consent resulting in a study population of 373 participants: 186 participants assigned to the STS group and 187 to the placebo group.The characteristics of the patients were well balanced in the 2 treatment groups at baseline (Tables SECONDARY OUTCOMES.Enzymatic infarct size was available for 248 patients: 124 in the STS and 124 in the placebo group.Missing values were caused by early transfer to referring hospital or hemolytic sample.The median peak creatine kinase MB value was 191 U/L (Q1, Q3: 81, 315 U/L) in the STS group compared with 168 U/L (Q1, Q3: 84, 289 U/L) in the placebo group (P ¼ 0.64) (Figure 1, Table3

FIGURE 2 3 de
FIGURE 2 Effect of Sodium Thiosulfate on Infarct Size Across Prespecified Subgroups

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A C C : B A S I C T O T R A N S L A T I O N A L S C I E N C E V O L .8 , N O . 1

R
E F E R E N C E S 15.Osipov RM, Robich MP, Feng J, et al.Effect of hydrogen sulfide in a porcine model of myocardial ischemia-reperfusion: Comparison of different administration regimens and characterization of PERSPECTIVES COMPETENCY IN MEDICAL KNOWLEDGE: In this proof-ofconcept study, administration of the hydrogen sulfide donor STS did not reduce infarct size, as measured by cardiac magnetic resonance, in patients presenting with acute STEMI.STS was also not associated with important harmful effects.TRANSLATIONAL OUTLOOK: Future clinical trials in populations at higher risk for large myocardial infarction may potentially uncover clinical benefit from STS or other hydrogen sulfide-donating compounds.J A C C : B A S I C T O T R A N S L A T I O N A L S C I E N C E V O L .8 , N O . 1

TABLE 1
Characteristics of the Patients at Baseline
). LVEF at 4month follow-up was determined by CMR in 230 patients.The average LVEF was 56.1% AE 7.6% in the STS group compared with 54.9% AE 8.7% in the placebo medication.A 23 AE 23 mm Hg decline in systolic blood pressure was observed after administration of the first dose of study medication in both treatment arms (P ¼ 0.55).Blood pressure remained constant after the second dose of study medication in both groups.Other adverse effects were mild and transient.No severe adverse events were observed that were considered to be related to STS treatment.

TABLE 3
Outcomes and Clinical Events at 4 Months Values are mean AE SD, median (Q1, Q3), or n (%). a Analyzed with Beta Regression adjusted for site, treatment, and anterior MI location.bResults only shown for CK-MB activity (University Medical Centre Groningen), other sites measured CK-MB mass (n ¼ 43); these results were consistent with results for CK-MB activity (data not shown).cDefinitions are available in the Supplemental Appendix.dCardiovascular death, reinfarction, reintervention.CABG ¼ coronary artery bypass graft surgery; ICD ¼ Implantable cardioverter-defibrillator; NSTEMI ¼ non-STsegment elevation myocardial infarction; STEMI ¼ ST-segment elevation myocardial infarction; STS ¼ sodium thiosulfate; other abbreviations as in Table
This study is supported by a grant of the Netherlands Organization for Health Research and Development and the Dutch Heart Foundation (ZonMW; project No: 95105012), Siemens health care GmbH (Push project IPA No.10), and the University Medical Centre Groningen.The subsidizers had no role in the design and conduct of the study, study analyses, drafting or editing of the manuscript, and its final contents.Dr Anthonio has received a Biotronic Teaching Grant, a Sanofi CTCue license for 1 year, and payment for Abiomed Impella Webcast; and Amgen paid for attendance at the New York Cardiovascular Symposium 2019.Dr van der Meer has received consultancy fees and/or grants from Novartis, Novo Nordisk, Vifor Pharma, AstraZeneca, Pfizer, Pharmacosmos, Pharma Nord and Ionis.Dr Nijveldt has received unrestricted research grants from Biotronik and Philips; and has received speaker fees from Sanofi Genzyme and Bayer.Dr Lipsic has received an educational grant from Abbott Medical.All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.ADDRESS FOR CORRESPONDENCE: Dr Pim van der Harst, Department of Cardiology, Division of Heart and Lungs, University Medical Centre Utrecht, P.O.Box 85500, 3508 GA Utrecht, the Netherlands.