Metformin in Diabetic Patients Undergoing Coronary Angiography

Study Overview
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Brief Summary
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The present study aims to evaluate the strict application of the 2018 European Society of Cardiology guidelines on myocardial revascularization, that recommends to check renal function if patients have taken metformin immediately before angiography and withhold metformin if renal function deteriorates. The aim of this study is to assess the safety of metformin in diabetic patients undergoing coronary angiography in terms of risk of lactic acidosis and to individuate eventual predictors of augmented lactate after coronary angiography.

Detailed Description
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The study is designed as an open-label (both physician and participant know that metformin will not be discontinued before PCI and in the following 48 hours), prospective, single arm study. In our historical cohort of diabetic patients taking metformin, we observed a mean value of lactate of 1.2+0.7 mmol/l. A total of 150 patients will be enrolled. Patients with any deviations from the study protocol will be enrolled in a parallel observational registry. The study consists of a screening phase, a 30-day observational phase, and an end-of-follow-up visit or phone interview. The total duration of participation in the study for each participant is approximately 30 days.

Official Title
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Metformin Continuation Safety in Diabetic Patients Undergoing Coronary Angiography

Conditions
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Diabetes Mellitus, Coronary Artery Disease, Lactic Acidosis With Diabetes Mellitus, Contrast-induced Nephropathy, Metformin Associated Lactic Acidosis

Intervention / Treatment
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* Drug: Metformin


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diabetic patients treated with metformin undergoing coronary angiography. Exclusion Criteria: Known coronary anatomy with planned complex percutaneous coronary intervention with high probability of large amount of contrast use (3.7 * estimated glomerular filtration rate; e.g.: 167 ml in a patients with an eGFR of 45 ml/min/1.73m2). Moderate to severe impairment of renal function (eGFR<45 ml/min). Moderate to severe impairment of liver function (Child-Pugh class B or C). Severely impaired left ventricular ejection fraction (LVEF <35%). Patients undergoing primary percutaneous coronary intervention (i.e., patients presenting with ST elevation myocardial infarction). Severe to very severe chronic obstructive pulmonary disease (GOLD class 3 to 4). Patients scheduled for cardiac surgery in the following 5 days. Inability to provide informed consent.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Metformin continuation<br> | Drug: Metformin<br>* Diabetic patients treated with metformin undergoing coronary angiography will not suspend metformin before and after PCI.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Increase in lactate of 20% | Lactate will be measured from a venous sampling at three different time points, before coronary angiography, the day after (not mandatory) and 3 days after coronary angiography | From preprocedural values (same day of the coronary angiography) to 72 hours after coronary angiography | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Contrast-associated acute kidney injury after coronary angiography. | Contrast-associated acute kidney injury was defined according to the KDIGO definition: increase in serum creatinine of 0.3 mg/dl within 48 hours from coronary angiography or >50% within 7 days (if creatinine after 7 days is available) or urine output of <0.5 ml/kg/hour for at least 6 hours | From 0 to 7 days after coronary angiography | 
| Metformin associated lactic acidosis | Lactic acidosis was defined as pH less than or equal to 7.35 and lactatemia greater than 2.2 mmol/L | At 24 and 72 hours after coronary angiography | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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metformin, coronary angiography, diabetes mellitus, lactic acidosis