The use of nitrates in the prevention of contrast-induced nephropathy in patients hospitalized after undergoing percutaneous coronary intervention

Inorganic nitrate benefits contrast-induced nephropathy after coronary angiography for acute coronary syndromes: the NITRATE-CIN trial

BACKGROUND AND AIMS

Contrast-induced nephropathy (CIN), also known as contrast-associated acute kidney injury (CA-AKI) underlies a significant proportion of the morbidity and mortality following coronary angiographic procedures in high-risk patients and remains a significant unmet need. In pre-clinical studies inorganic nitrate, which is chemically reduced in vivo to nitric oxide, is renoprotective but this observation is yet to be translated clinically. In this study, the efficacy of inorganic nitrate in the prevention of CIN in high-risk patients presenting with acute coronary syndromes (ACS) is reported.

METHODS

NITRATE-CIN is a double-blind, randomized, single-centre, placebo-controlled trial assessing efficacy of inorganic nitrate in CIN prevention in at-risk patients presenting with ACS. Patients were randomized 1:1 to once daily potassium nitrate (12 mmol) or placebo (potassium chloride) capsules for 5 days. The primary endpoint was CIN (KDIGO criteria). Secondary outcomes included kidney function [estimated glomerular filtration rate (eGFR)] at 3 months, rates of procedural myocardial infarction, and major adverse cardiac events (MACE) at 12 months. This study is registered with ClinicalTrials.gov: NCT03627130.

RESULTS

Over 3 years, 640 patients were randomized with a median follow-up of 1.0 years, 319 received inorganic nitrate with 321 received placebo. The mean age of trial participants was 71.0 years, with 73.3% male and 75.2% Caucasian; 45.9% had diabetes, 56.0% had chronic kidney disease (eGFR <60 mL/min) and the mean Mehran score of the population was 10. Inorganic nitrate treatment significantly reduced CIN rates (9.1%) vs. placebo (30.5%, P < .001). This difference persisted after adjustment for baseline creatinine and diabetes status (odds ratio 0.21, 95% confidence interval 0.13-0.34). Secondary outcomes were improved with inorganic nitrate, with lower rates of procedural myocardial infarction (2.7% vs. 12.5%, P = .003), improved 3-month renal function (between-group change in eGFR 5.17, 95% CI 2.94-7.39) and reduced 1-year MACE (9.1% vs. 18.1%, P = .001) vs. placebo.

CONCLUSIONS

In patients at risk of renal injury undergoing coronary angiography for ACS, a short (5 day) course of once-daily inorganic nitrate reduced CIN, improved kidney outcomes at 3 months, and MACE events at 1 year compared to placebo.

NITRATE-CIN Study: Protocol of a Randomized (1:1) Single-Center, UK, Double-Blind Placebo-Controlled Trial Testing the Effect of Inorganic Nitrate on Contrast-Induced Nephropathy in Patients Undergoing Coronary Angiography for Acute Coronary Syndromes

BACKGROUND

Contrast-induced nephropathy (CIN), an acute kidney injury resulting from the administration of intravascular iodinated contrast media, is a significant cause of morbidity/mortality following coronary angiographic procedures in high-risk patients. Despite preventative measures intended to mitigate the risk of CIN, there remains a need for novel effective treatments. Evidence suggests that delivery of nitric oxide (NO) through chemical reduction of inorganic nitrate to NO may offer a novel therapeutic strategy to reduce CIN and thus preserve long term renal function.

DESIGN

The NITRATE-CIN trial is a single-center, randomized, double-blind placebo-controlled trial, which plans to recruit 640 patients presenting with acute coronary syndromes (ACS) who are at risk of CIN. Patients will be randomized to either inorganic nitrate therapy (capsules containing 12 mmol KNO3) or placebo capsules containing potassium chloride (KCl) daily for 5 days. The primary endpoint is development of CIN using the Kidney Disease Improving Global Outcomes (KDIGO) criteria. A key secondary endpoint is renal function over a 3-month follow-up period. Additional secondary endpoints include serum renal biomarkers (e.g. neutrophil gelatinase-associated lipocalin) at 6 h, 48 h and 3 months following administration of contrast. Cost-effectiveness of inorganic nitrate therapy will also be evaluated.

SUMMARY

This study is designed to investigate the hypothesis that inorganic nitrate treatment decreases the rate of CIN as part of semi-emergent coronary angiography for ACS. Inorganic nitrate is a simple and easy to administer intervention that may prove useful in prevention of CIN in at-risk patients undergoing coronary angiographic procedures.

The effect of high-dose nitroglycerin on the cerebral saturation and renal function in cardiac surgery: A propensity score analysis

BACKGROUND

The aim of the study was to evaluate the effects of high-dose nitroglycerine administered during cardiopulmonary bypass on the intraoperative cerebral saturation and postoperative serum creatinine concentration in cardiac surgery.

METHODS

In a retrospective cohort study, a total of 239 patients undergoing cardiac surgery with cardiopulmonary bypass at a tertiary medical center were included. General anesthesia consisted of volatile anesthetic and either intravenous loading of high-dose nitroglycerin (infusion rate 10 to 20 mg·h with a total dose of ≥0.5 mg·kg) starting from rewarming of cardiopulmonary bypass throughout the end of the surgery (NTG group; N = 96) or without high-dose nitroglycerin (control group; N = 143). Data for intraoperative cerebral saturation and serum creatinine concentrations before and after cardiac surgery were collected. Propensity score method was used to adjust for potential confounders.

RESULTS

Patients receiving high-dose nitroglycerin had significantly lower mean arterial pressure and hematocrit levels during and after cardiopulmonary bypass. The risk of intraoperative cerebral desaturation was left-sided 23.9% versus 38.5% (p = 0.023), right-sided 28.1% versus 35.7% in the NTG and control groups, respectively. The risk of new-onset stroke and postoperative dialysis was 2.1% versus 6.3% and 1.0% versus 3.5% in the NTG and control groups, respectively.

CONCLUSION

An infusion of high-dose nitroglycerin initiating at rewarming of cardiopulmonary bypass and throughout the postbypass interval may induce hypotension and hemodilution in cardiac surgical patients. Cerebral saturation and renal function were well maintained without increasing the risk of stroke and renal replacement therapy after cardiac surgery with cardiopulmonary bypass.

Prevention of contrast-induced nephropathy by adequate hydration combined with isosorbide dinitrate for patients with renal insufficiency and congestive heart failure

BACKGROUND

Adequate hydration remains the mainstay of contrast-induced nephropathy prevention, and nitrates could reduce cardiac preload.

HYPOTHESIS

This study aimed to explore the adequate hydration with nitrates for patients with chronic kidney disease (CKD) and congestive heart failure (CHF) to reduce the risk of contrast-induced nephropathy (CIN) and at the same time avoid the acute heart failure.

METHODS

Three hundred and ninty-four consecutive patients with CKD and CHF undergoing coronary procedures were randomized to either adequate hydration with nitrates (n = 196) or to routine hydration (control group; n = 198). The adequate hydration group received continuous intravenous infusion of isosorbide dinitrate combined with intravenous infusion of isotonic saline at a rate of 1.5 mL/kg/h during perioperative period. The definition of CIN was a 25% or 0.5 mg/dL rise in serum creatinine over baseline. This trial is registered with www.clinicaltrials.gov, number NCT02718521.

RESULTS

Baseline characteristics were well-matched between the two groups. CIN occurred less frequently in adequate hydration group than the control group (12.8% vs 21.2%; P = 0.018). The incidence of acute heart failure did not differ between the two groups (8 [4.08%] vs 6[3.03%]; P = 0.599). Cumulative major adverse events (death, myocardial infarction, stoke, hospitalization for acute heart failure) during the 90-day follow-up were lower in the adequate hydration with nitrates group (P = 0.002).

CONCLUSIONS

Adequate hydration with nitrates can safely and effectively reduce the risk of CIN in patients with CKD and CHF.

Renal-related adverse effects of intravenous contrast media in computed tomography

Renal-related adverse effects of intravascular contrast media (CM) include contrast-induced nephropathy in computed tomography and angiography. While large retrospective studies have been published, the exact pathogenesis of this condition is still unknown. We review the main international guidelines, including the American College of Radiology white paper and the guidelines of European Society of Urogenital Radiology, Royal College of Radiologists and Canadian Association of Radiologists, as well as their references, regarding this subject. We present a simplified, concise approach to renal-related adverse effects of CM, taking into consideration the basis for each recommendation in these published guidelines. This will allow the reader to better understand the rationale behind appropriate patient preparation for cross-sectional imaging.

Renal protection: preconditioning for the prevention of contrast-induced nephropathy

As the numbers of interventional procedures are rising exponentially, identification of those patients at risk for renal complications has become even more important. Renal complications have been associated with increased morbidity and mortality after interventions. Risk factors have been studied to help identify those patients at increased risk for developing contrast-induced nephropathy. Hydration and medications have been studied as protective measures to decrease risk of renal complications. Preconditioning patients with intravenous hydration has been found to be the most helpful in circumventing postprocedural contrast-induced nephropathy.