Glutamate for Metabolic Intervention in Coronary Surgery II

Heart Failure Clinical Trial

— GLUTAMICSII  

Official title:

Phase III Study of Metabolic Intervention With Glutamate in Coronary Surgery II

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02592824
• Other study ID #: EudraCT 2011-006241-15
• Secondary ID: Dnr 5.1-2015-773
• Status: Completed
• Phase: Phase 3
• Start date: November 15, 2015
• Est. completion date: October 30, 2020

Study information

• Verified date: February 2023
• Source: University Hospital, Linkoeping
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The aim of GLUTAMICS II is to evaluate whether intravenous glutamate infusion surgery reduces the risk of postoperative heart failure as measured by plasma NT-proBNP in patients undergoing moderate to high-risk coronary artery bypass graft surgery. Patients accepted for coronary artery bypass surgery of at least two vessel disease or left main stenosis with or without concomitant procedure and considered to be at moderate to high surgical risk preoperatively with regard to postoperative heart failure will be studied. The primary endpoint is postoperative increase of NT-proBNP from the day before surgery to the third postoperative day.

Description:

In spite of the progress in cardiac surgery and perioperative management postoperative heart failure remains the leading cause of death and organ failure. Although acknowledged as a major problem in cardiac surgery there are no generally accepted criteria for the diagnosis of postoperative heart failure. This in turn could explain why treatment for postoperative heart failure is poorly documented with regard to clinical outcome.

Ischemia prior to cardiopulmonary bypass is the main cause of myocardial infarction after CABG. Available data demonstrate that ischemia and evolving myocardial infarction account for a large proportion of patients with postoperative heart failure after CABG.

Conventional treatment of postoperative heart failure presents a therapeutic dilemma as inotropic drugs not only aggravate ischemia and increase the size of evolving myocardial infarction, but also stimulate apoptotic processes that may have adverse long-term consequences.

The role of inotropes in cardiac surgery is therefore controversial. Some authors claim that liberal use of inotropes and goal-directed haemodynamic therapy can improve outcome whereas other report that liberal use of inotropes is associated with increased morbidity and mortality.

Alternative measures that can enhance myocardial recovery and function without putting further strain on the heart are therefore desirable.

Glutamate could influence outcome after myocardial ischemia by two different biochemical mechanisms. First, glutamate improves myocardial tolerance to ischemia by facilitated anaerobic metabolism and substrate level phosphorylation during ischemia. The second mechanism is related to the anaplerotic role of glutamate. Glutamate plays a key role for replenishment of Krebs cycle intermediates lost during ischemia, which enhances post-ischemic recovery of myocardial oxidative metabolism and function.

Promoting metabolic and functional recovery with metabolic support represents a novel concept in the treatment of heart failure after acute ischemia. Animal experiments suggest that glutamate increases myocardial tolerance to ischemia and that glutamate promotes post-ischemic recovery. Intravenous glutamate improved metabolic and hemodynamic recovery in humans early after CABG. Early clinical experience with intravenous metabolic support showed that the need for inotropes could be substantially reduced while clinical outcomes with regard to postoperative mortality, postoperative renal dysfunction and long-term survival compared favourably with the literature. This encouraging experience contributed to the initiation of the first GLUTAMICS-trial.

The first GLUTAMICS-trial investigated if intravenous glutamate infusion given in association with surgery for acute coronary syndrome could prevent myocardial injury, postoperative heart failure and reduce mortality. The study was negative with regard to the primary endpoint, which was a composite of postoperative mortality, perioperative myocardial infarction and left ventricular failure at weaning from cardiopulmonary bypass.

However, the study included a high proportion of low risk patients. Furthermore, the design of the primary endpoint suffered from liberal preemptive use of inotropes in patients anticipated to have weaning problems. It became evident at clinical endpoint committee meetings that preemptive use of inotropes prevented detection of weaning problems in patients who later developed severe heart failure. The secondary endpoint severe circulatory failure discriminated mild short-lasting heart failure at weaning from cardiopulmonary bypass from clinically significant heart failure requiring substantial circulatory support and leading to prolonged ICU stay or death. In the glutamate treated patients the relative risk of developing severe circulatory failure was reduced by more than 50% in most risk groups undergoing isolated CABG.

The first GLUTAMICS trial also included a substudy consisting of a blinded evaluation of NT-proBNP as a marker for postoperative heart failure.

Due to the lack of generally accepted criteria for postoperative heart failure, the evaluation of treatment is difficult. Consequently, comparative studies on different treatment strategies of heart failure after cardiac surgery are sparse given the magnitude of the problem.

Natriuretic peptides have been extensively studied in cardiology. In patients with chronic heart failure markedly increased BNP and NT-pro BNP levels are associated with poor prognosis. The response of natriuretic peptides to heart failure treatment has significant prognostic implications, and non-responders have a poor prognosis.

In cardiac surgery NT-proBNP increase was more pronounced in patients requiring inotropes. High postoperative levels of BNP and NT-proBNP were associated with worse outcome, both in the short- and long-term.

The first GLUTAMICS-trial permitted a blinded prospective evaluation of NT-proBNP by a clinical end-points committee relying on strict prespecified criteria with regard to postoperative heart failure. Data to be published demonstrate that postoperative NT-proBNP (day 1 and day 3) levels were strong predictors for severe heart failure associated with extended ICU stay or death. This implies that postoperative NT-proBNP could serve as a measure to assess efficacy of treatment and preventive strategies for postoperative heart failure. Albeit, a surrogate marker for postoperative heart failure it provides the advantage of a standardized and objective analysis, which makes the study reproducible.

AIM

The aim is to confirm findings in subgroups from the first GLUTAMICS-trial that intravenous glutamate infusion reduces the risk of postoperative heart failure in moderate to high risk patients undergoing coronary artery surgery by showing a reduced increase of NT-proBNP postoperatively.

PATIENTS

Patients accepted for coronary artery bypass surgery of at least two vessel disease or left main stenosis with or without concomitant procedure considered to be at moderate to high surgical risk preoperatively with regard to postoperative heart failure.

310 patients are planned to be included after informed written consent.

Exclusion criteria: patients with ambiguous food allergies that trigger shortness of breath, headache or flushing; patients> 85 years, previous cardiac surgery, patients who are in such bad condition that they cannot be asked to participate, patients who for linguistic or other reasons are unable to provide informed consent, severe renal failure with preoperative dialysis or calculated GFR <30 mL / min, patients requiring inotropic drugs or mechanical circulatory support (intra-aortic balloon pump) due to circulatory failure even before they enrolled in the study, patients who undergo surgery without the heart-lung machine (off-pump), patients who undergo concomitant Maze-procedure or surgery of ascending aorta.

STUDY DESIGN

The GLUTAMICS II is an investigator initiated prospective, randomized, placebo controlled, double-blind trial with parallel assignment to glutamate or placebo (saline). The trial is externally randomized and randomization is stratified for patients undergoing isolated CABG and for those having CABG with concomitant procedure.

INTERVENTION

Patients are randomly allocated to blinded intravenous infusion of 0.125M L-glutamic acid solution or saline at a rate of 1.65 ml/kg and hour commencing at or up to 20 minutes before the release of aortic cross-clamp. The infusion is continued for two hours after declamping the aorta after which an additional 50 ml is given at a halved infusion rate.

PRIMARY ENDPOINT

The primary endpoint is a postoperative increase of NT-proBNP from the day before surgery to the third postoperative day.

SECONDARY ENDPOINTS

Secondary endpoints are the absolute postoperative plasma levels of NT-proBNP day 1 and day 3.

SAFETY VARIABLES

Postoperative mortality (30 days + hospitals), stroke within 24 hours and SUSARs

SAMPLE SIZE

Sample size is based on available results from the first GLUTAMICS study. In that study, the following increase of NT-proBNP from the preoperative value to third postoperative day (mean ± SD) were observed in patients with LVEF ≤ 0.30 or EuroSCORE II ≥ 3.0 undergoing coronary artery surgery for with or without concomitant procedure.

Glutamate (n=71): 5261 ± 4409

Placebo (n=62): 7112 ± 6454

Sample size assessment by external statistical expertise (80% power, 5% risk level; two-sided test) suggests 141 patients in each group. To account for failed sampling and other loss we plan a total of 310 patients.

INTERIM ANALYSIS

Interim analysis will be performed by an external independent statistician after 160 patients by an adaptive design as reported in detail to the Swedish Medical Product Agency.

Update August 30, 2020: Interim analysis in December 2017 supported the original sample size assessment and the aim was set to reach 300 patients with complete data for the primary endpoint. The original goal of 280 patients with complete data has been reached and the study is approaching 300 but as study solutions will expire September 30, 2020 this will be the last date for inclusion of patients into the trial.

ETHICAL CONSIDERATIONS

A concern with the use of glutamate is that it may act as an excitotoxin under certain conditions and participate in events leading to neurological damage. However, brain tissue concentrations of glutamate are more than fifty-fold higher than in blood whereas the dosage used only elevates blood levels three-fold. Neurological outcome has been carefully monitored when intravenous infusions have been used in clinical practice without evidence of adverse effects. No evidence of subclinical neurological injury associated with intravenous glutamate infusion could be detected by the S-100B measurements and no differences in neurological outcome or other adverse events were found in the GLUTAMICS trial.

After written informed consent eligible patients will be enrolled in the study. The study will be performed according to the Helsinki Declaration of Human Rights and is approved by the Regional Ethical Review Board in Linköping (Dnr 2011/498-31; Dnr 2015/333-32).

The Swedish Medical Products Agency requests surveillance and unblinding in cases of CT-verified stroke within 24 hours of surgery, mortality and suspected unexpected serious adverse reactions (SUSAR). External monitoring of all key data, written informed consent and unblinding procedures will be done.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 321
• Est. completion date: October 30, 2020
• Est. primary completion date: October 30, 2020
• Accepts healthy volunteers: No
• Gender: All
• Age group: 20 Years to 85 Years

Eligibility

Inclusion Criteria:

Patients accepted for coronary artery bypass surgery of at least two vessel disease or left main stenosis with or without concomitant procedure considered to be at moderate to high surgical risk preoperatively with regard to postoperative heart failure due to:

• EuroSCORE II = 3.0 with at least one of the following cardiac or procedure related risk factors:

• LVEF = 0.50

• CCS class IV

• Recent Myocardial Infarct (= 90 days)

• Emergency / Urgent procedure (as defined in EuroSCORE II)

• CABG with aortic or mitral valve procedure

OR

• LVEF = 0.30 regardless of EuroSCORE II

Exclusion Criteria:

• age > 85 years

• ambiguous food allergies that trigger shortness of breath, headache or flushing

• previous cardiac surgery

• patients who are in such bad condition that they cannot be asked to participate

• patients who because of linguistic or other reasons are unable to provide informed consent

• severe renal failure with preoperative dialysis or calculated GFR <30 mL / min

• patients requiring mechanical circulatory support (intra-aortic balloon pump) due to circulatory failure before they are enrolled in the study

• surgery without heart-lung machine (off-pump)

• concomitant Maze-procedure

• surgery of ascending aorta

• surgery of both aortic and mitral valve

Related Conditions & MeSH terms

• Coronary Artery Bypass Surgery
• Heart Failure
• Postoperative Complications

Intervention

Drug:
• glutamate infusion
Intravenous infusion of 0.125M L-glutamic acid solution at a rate of 1.65 ml/kg BW and hour commencing at or up to 20 minutes before the release of aortic cross-clamp. The infusion is continued for two hours after declamping the aorta after which an additional 50 ml is given at a halved infusion rate.
• saline infusion
Intravenous infusion of saline at a rate of 1.65 ml/kg BW and hour commencing at or up to 20 minutes before the release of aortic cross-clamp. The infusion is continued for two hours after declamping the aorta after which an additional 50 ml is given at a halved infusion rate.

Locations

Country	Name	City	State
Sweden	Sahlgrenska University Hospital	Gothenburg
Sweden	University Hospital Linköping	Linköping
Sweden	University Hospital Örebro	Örebro
Sweden	University Hospital Umeå	Umeå

Sponsors (4)

Lead Sponsor	Collaborator
University Hospital, Linkoeping	Region Örebro County, Sahlgrenska University Hospital, Sweden, University Hospital, Umeå

Country where clinical trial is conducted

Sweden, 

References & Publications (33)

Aya HD, Cecconi M, Hamilton M, Rhodes A. Goal-directed therapy in cardiac surgery: a systematic review and meta-analysis. Br J Anaesth. 2013 Apr;110(4):510-7. doi: 10.1093/bja/aet020. Epub 2013 Feb 27. — View Citation

Dahlin LG, Olin C, Svedjeholm R. Perioperative myocardial infarction in cardiac surgery--risk factors and consequences. A case control study. Scand Cardiovasc J. 2000 Oct;34(5):522-7. doi: 10.1080/140174300750064710. — View Citation

de Lemos JA, McGuire DK, Drazner MH. B-type natriuretic peptide in cardiovascular disease. Lancet. 2003 Jul 26;362(9380):316-22. doi: 10.1016/S0140-6736(03)13976-1. — View Citation

Engelman RM, Rousou JA, Flack JE 3rd, Iyengar J, Kimura Y, Das DK. Reduction of infarct size by systemic amino acid supplementation during reperfusion. J Thorac Cardiovasc Surg. 1991 May;101(5):855-9. — View Citation

Fellahi JL, Parienti JJ, Hanouz JL, Plaud B, Riou B, Ouattara A. Perioperative use of dobutamine in cardiac surgery and adverse cardiac outcome: propensity-adjusted analyses. Anesthesiology. 2008 Jun;108(6):979-87. doi: 10.1097/ALN.0b013e318173026f. — View Citation

Fox AA, Nascimben L, Body SC, Collard CD, Mitani AA, Liu KY, Muehlschlegel JD, Shernan SK, Marcantonio ER. Increased perioperative b-type natriuretic peptide associates with heart failure hospitalization or heart failure death after coronary artery bypass graft surgery. Anesthesiology. 2013 Aug;119(2):284-94. doi: 10.1097/ALN.0b013e318299969c. — View Citation

Giglio M, Dalfino L, Puntillo F, Rubino G, Marucci M, Brienza N. Haemodynamic goal-directed therapy in cardiac and vascular surgery. A systematic review and meta-analysis. Interact Cardiovasc Thorac Surg. 2012 Nov;15(5):878-87. doi: 10.1093/icvts/ivs323. Epub 2012 Jul 24. — View Citation

Gillies M, Bellomo R, Doolan L, Buxton B. Bench-to-bedside review: Inotropic drug therapy after adult cardiac surgery -- a systematic literature review. Crit Care. 2005 Jun;9(3):266-79. doi: 10.1186/cc3024. Epub 2004 Dec 16. — View Citation

Haas GS, DeBoer LW, O'Keefe DD, Bodenhamer RM, Geffin GA, Drop LJ, Teplick RS, Daggett WM. Reduction of postischemic myocardial dysfunction by substrate repletion during reperfusion. Circulation. 1984 Sep;70(3 Pt 2):I65-74. — View Citation

Karlstrom P, Alehagen U, Boman K, Dahlstrom U; UPSTEP-study group. Brain natriuretic peptide-guided treatment does not improve morbidity and mortality in extensively treated patients with chronic heart failure: responders to treatment have a significantly better outcome. Eur J Heart Fail. 2011 Oct;13(10):1096-103. doi: 10.1093/eurjhf/hfr078. Epub 2011 Jun 29. Erratum In: Eur J Heart Fail. 2012 May;14(5):563. von den Luederer Tomas [corrected to von Lueder, Thomas G]. — View Citation

Khoynezhad A, Jalali Z, Tortolani AJ. Apoptosis: pathophysiology and therapeutic implications for the cardiac surgeon. Ann Thorac Surg. 2004 Sep;78(3):1109-18. doi: 10.1016/j.athoracsur.2003.06.034. — View Citation

Lazar HL, Buckberg GD, Foglia RP, Manganaro AJ, Maloney JV Jr. Detrimental effects of premature use of inotropic drugs to discontinue cardiopulmonary bypass. J Thorac Cardiovasc Surg. 1981 Jul;82(1):18-25. — View Citation

Lazar HL, Buckberg GD, Manganaro AJ, Becker H, Maloney JV Jr. Reversal of ischemic damage with amino acid substrate enhancement during reperfusion. Surgery. 1980 Nov;88(5):702-9. — View Citation

Maroko PR, Kjekshus JK, Sobel BE, Watanabe T, Covell JW, Ross J Jr, Braunwald E. Factors influencing infarct size following experimental coronary artery occlusions. Circulation. 1971 Jan;43(1):67-82. doi: 10.1161/01.cir.43.1.67. No abstract available. — View Citation

Mebazaa A, Pitsis AA, Rudiger A, Toller W, Longrois D, Ricksten SE, Bobek I, De Hert S, Wieselthaler G, Schirmer U, von Segesser LK, Sander M, Poldermans D, Ranucci M, Karpati PC, Wouters P, Seeberger M, Schmid ER, Weder W, Follath F. Clinical review: practical recommendations on the management of perioperative heart failure in cardiac surgery. Crit Care. 2010;14(2):201. doi: 10.1186/cc8153. Epub 2010 Apr 28. — View Citation

Nozohoor S, Nilsson J, Algotsson L, Sjogren J. Postoperative increase in B-type natriuretic peptide levels predicts adverse outcome after cardiac surgery. J Cardiothorac Vasc Anesth. 2011 Jun;25(3):469-75. doi: 10.1053/j.jvca.2010.07.002. Epub 2010 Sep 9. — View Citation

O'Connor GT, Birkmeyer JD, Dacey LJ, Quinton HB, Marrin CA, Birkmeyer NJ, Morton JR, Leavitt BJ, Maloney CT, Hernandez F, Clough RA, Nugent WC, Olmstead EM, Charlesworth DC, Plume SK. Results of a regional study of modes of death associated with coronary artery bypass grafting. Northern New England Cardiovascular Disease Study Group. Ann Thorac Surg. 1998 Oct;66(4):1323-8. doi: 10.1016/s0003-4975(98)00762-0. — View Citation

Peuhkurinen KJ. Regulation of the tricarboxylic acid cycle pool size in heart muscle. J Mol Cell Cardiol. 1984 Jun;16(6):487-95. doi: 10.1016/s0022-2828(84)80637-9. — View Citation

Pisarenko OI, Lepilin MG, Ivanov VE. Cardiac metabolism and performance during L-glutamic acid infusion in postoperative cardiac failure. Clin Sci (Lond). 1986 Jan;70(1):7-12. doi: 10.1042/cs0700007. — View Citation

Pisarenko OI, Novikova EB, Serebryakova LI, Tskitishvili OV, Ivanov VE, Studneva IM. Function and metabolism of dog heart in ischemia and in subsequent reperfusion: effect of exogenous glutamic acid. Pflugers Arch. 1985 Dec;405(4):377-83. doi: 10.1007/BF00595691. — View Citation

Pisarenko OI. Mechanisms of myocardial protection by amino acids: facts and hypotheses. Clin Exp Pharmacol Physiol. 1996 Aug;23(8):627-33. doi: 10.1111/j.1440-1681.1996.tb01748.x. — View Citation

Rau EE, Shine KI, Gervais A, Douglas AM, Amos EC 3rd. Enhanced mechanical recovery of anoxic and ischemic myocardium by amino acid perfusion. Am J Physiol. 1979 Jun;236(6):H873-9. doi: 10.1152/ajpheart.1979.236.6.H873. No abstract available. — View Citation

Reyes G, Fores G, Rodriguez-Abella RH, Cuerpo G, Vallejo JL, Romero C, Pinto A. NT-proBNP in cardiac surgery: a new tool for the management of our patients? Interact Cardiovasc Thorac Surg. 2005 Jun;4(3):242-7. doi: 10.1510/icvts.2004.101576. Epub 2005 Mar 30. — View Citation

Safer B. The Metabolic Significance of the Malate-Aspartate Cycle in Heart. Circ Res. 1975 Nov;37(5):527-33. doi: 10.1161/01.res.37.5.527. No abstract available. — View Citation

Shahin J, DeVarennes B, Tse CW, Amarica DA, Dial S. The relationship between inotrope exposure, six-hour postoperative physiological variables, hospital mortality and renal dysfunction in patients undergoing cardiac surgery. Crit Care. 2011 Jul 7;15(4):R162. doi: 10.1186/cc10302. — View Citation

Slogoff S, Keats AS. Does perioperative myocardial ischemia lead to postoperative myocardial infarction? Anesthesiology. 1985 Feb;62(2):107-14. doi: 10.1097/00000542-198502000-00002. — View Citation

Svedjeholm R, Huljebrant I, Hakanson E, Vanhanen I. Glutamate and high-dose glucose-insulin-potassium (GIK) in the treatment of severe cardiac failure after cardiac operations. Ann Thorac Surg. 1995 Feb;59(2 Suppl):S23-30. doi: 10.1016/0003-4975(94)00918-w. — View Citation

Svedjeholm R, Vanhanen I, Hakanson E, Joachimsson PO, Jorfeldt L, Nilsson L. Metabolic and hemodynamic effects of intravenous glutamate infusion early after coronary operations. J Thorac Cardiovasc Surg. 1996 Dec;112(6):1468-77. doi: 10.1016/S0022-5223(96)70005-3. — View Citation

Svedjeholm R, Vidlund M, Vanhanen I, Hakanson E. A metabolic protective strategy could improve long-term survival in patients with LV-dysfunction undergoing CABG. Scand Cardiovasc J. 2010 Feb;44(1):45-58. doi: 10.3109/14017430903531008. — View Citation

Thackray S, Easthaugh J, Freemantle N, Cleland JG. The effectiveness and relative effectiveness of intravenous inotropic drugs acting through the adrenergic pathway in patients with heart failure-a meta-regression analysis. Eur J Heart Fail. 2002 Aug;4(4):515-29. doi: 10.1016/s1388-9842(02)00041-7. — View Citation

Vanky F, Hakanson E, Maros T, Svedjeholm R. Different characteristics of postoperative heart failure after surgery for aortic stenosis and coronary disease. Scand Cardiovasc J. 2004 Jun;38(3):152-8. doi: 10.1080/14017430410029734. — View Citation

Vanky FB, Hakanson E, Svedjeholm R. Long-term consequences of postoperative heart failure after surgery for aortic stenosis compared with coronary surgery. Ann Thorac Surg. 2007 Jun;83(6):2036-43. doi: 10.1016/j.athoracsur.2007.01.031. — View Citation

Vidlund M, Hakanson E, Friberg O, Juhl-Andersen S, Holm J, Vanky F, Sunnermalm L, Borg JO, Sharma R, Svedjeholm R. GLUTAMICS--a randomized clinical trial on glutamate infusion in 861 patients undergoing surgery for acute coronary syndrome. J Thorac Cardiovasc Surg. 2012 Oct;144(4):922-930.e7. doi: 10.1016/j.jtcvs.2012.05.066. Epub 2012 Jun 19. — View Citation

* Note: There are 33 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Other	Copeptin Substudy	Exploratory assessment of plasma-Copeptin related to NT-proBNP	preoperative, first and third postoperative day
Primary	Postoperative Increase of Plasma NT-proBNP	Postoperative increase of NT-proBNP reflects postoperative myocardial dysfunction sustained in association with surgery. NT-proBNP usually peaks on the third to fourth postoperative day after coronary artery bypass surgery.; In the first GLUTAMICS trial a good agreement between hemodynamic criteria for postoperative heart failure and postoperative NT-proBNP was found.	from the day before surgery to the third postoperative day
Secondary	Postoperative Plasma Level of NT-proBNP	Postoperative NT-proBNP reflects postoperative myocardial dysfunction.	first postoperative day
Secondary	Postoperative Plasma Level of NT-proBNP	Postoperative NT-proBNP reflects postoperative myocardial dysfunction.	third postoperative day
Secondary	Number of Participants With Incidence of Stroke	Postoperative stroke was defined as neurological or cognitive deficit with a cerebral injury verified on (Computed Tomography) CT-scan. All suspected cases of stroke underwent CT-scan.; Stroke within 24 h of surgery was defined as a stroke that occurred within 24 h of surgery or signs of a stroke, when first assessable in deeply sedated patients on a ventilator.	within 24 hours from surgery
Secondary	Incidence of Mortality	Postoperative mortality was defined as mortality within 30 days of surgery.	up to 30 days
Secondary	Incidence of Unexpected Adverse Events	suspected unexpected serious adverse reaction	within 24 hours from infusion