Intravenous nitroglycerin reduces ischaemia in unstable angina pectoris: a double-blind placebo-controlled study

2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes" incorporates new evidence since the "2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction" and the corresponding "2014 AHA/ACC Guideline for the Management of Patients With Non-ST-Elevation Acute Coronary Syndromes" and the "2015 ACC/AHA/SCAI Focused Update on Primary Percutaneous Coronary Intervention for Patients With ST-Elevation Myocardial Infarction." The "2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes" and the "2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization" retire and replace, respectively, the "2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease."

METHODS

A comprehensive literature search was conducted from July 2023 to April 2024. Clinical studies, systematic reviews and meta-analyses, and other evidence conducted on human participants were identified that were published in English from MEDLINE (through PubMed), EMBASE, the Cochrane Library, Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline.

STRUCTURE

Many recommendations from previously published guidelines have been updated with new evidence, and new recommendations have been created when supported by published data.

2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The "2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes" incorporates new evidence since the "2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction" and the corresponding "2014 AHA/ACC Guideline for the Management of Patients With Non-ST-Elevation Acute Coronary Syndromes" and the "2015 ACC/AHA/SCAI Focused Update on Primary Percutaneous Coronary Intervention for Patients With ST-Elevation Myocardial Infarction." The "2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes" and the "2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization" retire and replace, respectively, the "2016 ACC/AHA Guideline Focused Update on Duration of Dual Antiplatelet Therapy in Patients With Coronary Artery Disease."

METHODS

A comprehensive literature search was conducted from July 2023 to April 2024. Clinical studies, systematic reviews and meta-analyses, and other evidence conducted on human participants were identified that were published in English from MEDLINE (through PubMed), EMBASE, the Cochrane Library, Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline.

STRUCTURE

Many recommendations from previously published guidelines have been updated with new evidence, and new recommendations have been created when supported by published data.

Mnemonic to assist in the treatment of NSTE-ACS

Acute care NPs are in an ideal position to diagnose and manage non-ST-segment elevation (NSTE)-acute coronary syndrome (ACS) by implementing guideline-driven medical interventions. Utilizing mnemonics improves efficiency of clinicians in practice. This article introduces a mnemonic to assist NPs in their response to patients with NSTE-ACS.

Non-ST-Segment Acute Coronary Syndromes

Acute coronary syndrome (ACS) represents an umbrella of ischemic myocardial disease and diagnoses encompassing unstable angina (UA), non-ST-elevation myocardial infarction (NSTEMI), and ST-elevation myocardial infarction (STEMI). UA and NSTEMI for all intents and purposes, share similar pathophysiology, but at increasing severity. This article focuses on the diagnosis, risk stratification, management, and strategies that impact outcomes in NSTEMI.

2018 Guidelines of the Taiwan Society of Cardiology, Taiwan Society of Emergency Medicine and Taiwan Society of Cardiovascular Interventions for the management of non ST-segment elevation acute coronary syndrome

In Taiwan, the incidence of non-ST segment elevation acute coronary syndrome (NSTE-ACS) continues to increase in recent years. The purpose of this guideline is to help health care professionals in Taiwan to use adequate tests and treatments for management of NSTE-ACS. For rapid diagnosis, in addition to history and physical examination, 0/3 h rapid diagnosis protocol with high sensitivity cardiac troponin assay is recommended in this guideline. Dual antiplatelet and anticoagulation therapies are important parts in the initial treatment. Risk stratification should be performed to identify high risk patients for early coronary angiography. Through evaluation of the coronary anatomy and other clinical factors, the decision for coronary revascularization, either by percutaneous coronary intervention or coronary artery bypass grafting, should be decided by the heart team. The duration of dual antiplatelet therapy should be given for at least 12 months after discharge. Other secondary preventive medications are also recommended for long term use.

The Role of Nitroglycerin and Other Nitrogen Oxides in Cardiovascular Therapeutics

The use of nitroglycerin in the treatment of angina pectoris began not long after its original synthesis in 1847. Since then, the discovery of nitric oxide as a biological effector and better understanding of its roles in vasodilation, cell permeability, platelet function, inflammation, and other vascular processes have advanced our knowledge of the hemodynamic (mostly mediated through vasodilation of capacitance and conductance arteries) and nonhemodynamic effects of organic nitrate therapy, via both nitric oxide-dependent and -independent mechanisms. Nitrates are rapidly absorbed from mucous membranes, the gastrointestinal tract, and the skin; thus, nitroglycerin is available in a number of preparations for delivery via several routes: oral tablets, sublingual tablets, buccal tablets, sublingual spray, transdermal ointment, and transdermal patch, as well as intravenous formulations. Organic nitrates are commonly used in the treatment of cardiovascular disease, but clinical data limit their use mostly to the treatment of angina. They are also used in the treatment of subsets of patients with heart failure and pulmonary hypertension. One major limitation of the use of nitrates is the development of tolerance. Although several agents have been studied for use in the prevention of nitrate tolerance, none are currently recommended owing to a paucity of supportive clinical data. Only 1 method of preventing nitrate tolerance remains widely accepted: the use of a dosing strategy that provides an interval of no or low nitrate exposure during each 24-h period. Nitric oxide's important role in several cardiovascular disease mechanisms continues to drive research toward finding novel ways to affect both endogenous and exogenous sources of this key molecular mediator.

Clinical effect of ticagrelor administered in acute coronary syndrome patients following percutaneous coronary intervention

The aim of the present study was to retrospectively analyze the clinical effect and safety of ticagrelor administration in acute coronary syndrome (ACS) patients following percutaneous coronary intervention (PCI). In total, 203 patients were enrolled, who were confirmed with ACS between March 2013 and May 2013, and had successfully undergone PCI. The patients were randomly divided into two groups, including the clopidogrel (group A, n=108) and ticagrelor groups (group B, n=95). Patients in group A were treated with a 600 mg loading dose of clopidogrel followed by 75 mg/day clopidogrel plus 100 mg/day aspirin. Patients in group B received a 180 mg loading dose of ticagrelor followed by 90 mg ticagrelor twice daily plus 100 mg/day aspirin. Light transmission aggregometry was performed to measure the platelet aggregation rate prior to and following 4 weeks of anti-platelet drug treatment. In addition, the rate of cardiovascular events and the adverse drug reactions were recorded within a 1-year treatment period. Compared with the clopidogrel group, the rate of recurrent angina in the ticagrelor group was significantly lower (P=0.05). However, the rate of dyspnea in the ticagrelor group was significantly higher when compared with that in the clopidogrel group (P=0.03). After 4 weeks of treatment, the reduction in the platelet aggregation rate was significantly different between the two groups (P<0.05). Therefore, ticagrelor, which is a novel antiplatelet aggregation drug, may reduce the rate of the adverse cardiovascular events in ACS patients following PCI, but a higher incidence of side-effects, such as dyspnea, may be observed.

Concomitant nitrates enhance clopidogrel response during dual anti-platelet therapy

BACKGROUND

Despite advances in modern anti-platelet strategies, clopidogrel still remains the cornerstone of dual anti-platelet therapy (DAPT) in patients undergoing percutaneous coronary interventions (PCI). There is some inconclusive evidence that response after clopidogrel may be impacted by concomitant medications, potentially affecting clinical outcomes. Sustained released nitrates (SRN) are commonly used together with clopidogrel in post-PCI setting for mild vasodilatation and nitric oxide-induced platelet inhibition.

METHODS

We prospectively enrolled 458 patients (64.5 ± 9.6 years old, and 73.4% males) following PCI undergoing DAPT with clopidogrel and aspirin. Platelet reactivity was assessed by the VerifyNow™ P2Y12 assay at the maintenance outpatient setting.

RESULTS

Concomitant SRN (n=266) significantly (p=0.008) enhanced platelet inhibition after DAPT (251.6 ± 80.9PRU) when compared (232.1 ± 73.5PRU) to the SRN-free (n=192) patients. Multivariate logistic regression analysis with the cut-off value of 253 PRU for defining heightened platelet reactivity confirmed independent correlation of more potent platelet inhibition during DAPT and use of SRN (Relative risk=1.675; Odds ratio [1.059-2.648]; p=0.027). In contrast, statins, calcium-channel blockers, beta blockers, angiotensin receptor blockers, ACE-inhibitors, diuretics, and anti-diabetic agents did not significantly impact platelet inhibition following DAPT.

CONCLUSION

The synergic ability of SRN to enhance response during DAPT may have important clinical implications with regard to better cardiovascular protection, but extra bleeding risks, requiring further confirmation in a large randomized study.

The use of regional cerebral oximetry monitoring during controlled hypotension: a case series

Regional cerebral oximetry monitoring was used to guide nitroglycerin infusion and IV fluid administration during controlled hypotension in order to optimize each individual patient's mean arterial pressure in a series of 20 consecutive patients who underwent major open urological or abdominal surgery. Although controlled hypotension offers a definite benefit in patients undergoing complex surgery where blood loss will be elevated or would severely compromise the surgical field, it is not without risk as low arterial pressure may compromise tissue perfusion and promote ischemia. In this case series, despite an average mean arterial pressure decrease of 19.5 % (p < 0.001), cerebral oximetry values increased by an average of 22.7 % (p < 0.001) after the nitroglycerin infusion had been initiated (220 mcg/min average). Patients received an average of 3.15L crystalloid and 437 ml albumin in fluid resuscitation.

Effect of early treatment with anti-hypertensive drugs on short and long-term mortality in patients with an acute cardiovascular event

BACKGROUND

Acute cardiovascular events represent a therapeutic challenge. Blood pressure lowering drugs are commonly used and recommended in the early phase of these settings. This review analyses randomized controlled trial (RCT) evidence for this approach.

OBJECTIVES

To determine the effect of immediate and short-term administration of anti-hypertensive drugs on all-cause mortality, total non-fatal serious adverse events (SAE) and blood pressure, in patients with an acute cardiovascular event, regardless of blood pressure at the time of enrollment.

SEARCH STRATEGY

MEDLINE, EMBASE, and Cochrane clinical trial register from Jan 1966 to February 2009 were searched. Reference lists of articles were also browsed. In case of missing information from retrieved articles, authors were contacted.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing anti-hypertensive drug with placebo or no treatment administered to patients within 24 hours of the onset of an acute cardiovascular event.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data and assessed risk of bias. Fixed effects model with 95% confidence intervals (CI) were used. Sensitivity analyses were also conducted.

MAIN RESULTS

Sixty-five RCTs (N=166,206) were included, evaluating four classes of anti-hypertensive drugs: ACE inhibitors (12 trials), beta-blockers (20), calcium channel blockers (18) and nitrates (18). Acute stroke was studied in 6 trials (all involving CCBs). Acute myocardial infarction was studied in 59 trials. In the latter setting immediate nitrate treatment (within 24 hours) reduced all-cause mortality during the first 2 days (RR 0.81, 95%CI [0.74,0.89], p<0.0001). No further benefit was observed with nitrate therapy beyond this point. ACE inhibitors did not reduce mortality at 2 days (RR 0.91,95%CI [0.82, 1.00]), but did after 10 days (RR 0.93, 95%CI [0.87,0.98] p=0.01). No other blood pressure lowering drug administered as an immediate treatment or short-term treatment produced a statistical significant mortality reduction at 2, 10 or >/=30 days. There was not enough data studying acute stroke, and there were no RCTs evaluating other acute cardiovascular events.

AUTHORS' CONCLUSIONS

Nitrates reduce mortality (4-8 deaths prevented per 1000) at 2 days when administered within 24 hours of symptom onset of an acute myocardial infarction. No mortality benefit was seen when treatment continued beyond 48 hours. Mortality benefit of immediate treatment with ACE inhibitors post MI at 2 days did not reach statistical significance but the effect was significant at 10 days (2-4 deaths prevented per 1000). There is good evidence for lack of a mortality benefit with immediate or short-term treatment with beta-blockers and calcium channel blockers for acute myocardial infarction.

Side effects of using nitrates to treat heart failure and the acute coronary syndromes, unstable angina and acute myocardial infarction

Nitrates are potent venous dilators and anti-ischemic agents. They are widely used for the relief of chest pain and pulmonary congestion in patients with acute coronary syndromes and heart failure. Nitrates, however, do not reduce mortality in patients with acute coronary syndromes. Combination of nitrates and hydralazine when given in addition to beta-blockers and angiotensin-converting enzyme (ACE) inhibitors reduce mortality and heart failure hospitalizations in patients with heart failure due to left ventricular systolic dysfunction who are of African-American origin. Side effects during nitrate therapy are common but are less well described in the literature compared with the reported side effects in patients with stable angina pectoris. The reported incidence of side effects varies highly among different studies and among various disease states. Headache is the most commonly reported side effect with an incidence of 12% in acute heart failure, 41-73% in chronic heart failure, 3-19% in unstable angina and 2-26% in acute myocardial infarction. The reported incidence of hypotension also differs: 5-10% in acute heart failure, 20% in chronic heart failure, 9% in unstable angina and < 1-48% in acute myocardial infarction, with the incidence being much higher with concomitant nitrate therapy plus angiotensin-converting enzyme inhibitors. Reported incidence of dizziness is as low as 1% in patients with acute myocardial infarction to as high as 29% in patients with heart failure. Severe headaches and/or symptomatic hypotension may necessitate discontinuation of nitrate therapy. Severe life threatening hypotension or even death may occur when nitrates are used in patients with acute inferior myocardial infarction associated with right ventricular dysfunction or infarction, or with concomitant use of phosphodiesterase-5 inhibitors or N-acetylcysteine. Despite the disturbing observational reports in the literature that continuous and prolonged use of nitrates may lead to increased mortality and recurrent myocardial infarction in patients with stable coronary artery disease, no such adverse effects of nitrates have been reported in the large randomized trials in patients with acute myocardial infarction or chronic heart failure.

Usefulness of carvedilol in unstable angina pectoris

The safety and efficacy of adding oral carvedilol (25 mg twice daily) to standardized treatment of unstable angina was assessed in a multicenter, randomized, double-blind, placebo- controlled trial on 116 patients with acute unstable angina. Patients were monitored in an intensive care unit and underwent 48-hour Holter monitoring to assess transient ischemia. Carvedilol as adjunctive therapy resulted in a significant reduction of median heart rate (65 vs 75 beats/min, p <0.05), mean systolic blood pressure (133 vs 130 mm Hg, p <0.05), and mean rate-pressure product (8,337 vs 10,042, p <0.05). Carvedilol reduced the ischemic burden during 48 hours of treatment by 75% (49 vs 204 minutes), including a 36% reduction of patients with ischemic episodes (p <0.05), a 66% reduction of the mean number of ischemic episodes (8 vs 24, p <0.05), and a 76% reduction in the mean duration of ischemic episodes (50 vs 205 minutes, p <0.05). Side effects occurred in 8 of 59 patients (13.6%) in the carvedilol group and in 5 of 54 patients (8.8%) given placebo. Although not significant, the early onset of maximal blood pressure reduction and the delayed effect on heart rate were closely correlated to drug-induced hypotension and bradycardia in the carvedilol group. Thus, carvedilol as an adjunctive to standardized treatment effectively reduces heart rate and blood pressure, and thus the ischemic burden in patients with unstable angina pectoris, but requires close monitoring of patients at risk for bradycardia or hypotension.