Effect of transdermal nitroglycerin or N-acetylcysteine, or both, in the long-term treatment of unstable angina pectoris

Impact of N-Acetyl-Cysteine on Ischemic Stumps Following Major Lower Extremity Amputation: A Pilot Randomized Clinical Trial

OBJECTIVE

To evaluate the impact of N-acetyl-cysteine (NAC) on amputation stump perfusion and healing in patients with critical limb-threatening ischemia (CLTI).

BACKGROUND

Patients with CLTI are at increased risk of poor amputation site healing leading to increased procedure-associated morbidity.

METHODS

In a pilot, double-blind, placebo-controlled, randomized controlled trial, patients with CLTI undergoing major elective lower extremity amputation were randomized 1:1 to intravenous NAC (1200 mg twice-daily) or placebo for up to 5 days postoperatively. Primary outcomes were change in stump perfusion at postoperative day 3 (POD3) and POD5, and healing at POD30. Stumps were serially evaluated for wound healing, and tissue perfusion was evaluated using noninvasive laser-assisted fluorescent angiography.

RESULTS

Thirty-three patients were randomized to NAC (n = 16) or placebo (n = 17). Thirty-one patients were eligible for intent-to-treat analysis (NAC14; placebo17). Twenty patients (NAC7; placebo13) had amputation stump perfusion defects at POD0 and were considered high-risk for poor healing. Intent-to-treat analysis revealed no significant differences between treatment groups. Subgroup analysis of high-risk patients revealed differences in stump perfusion defect size (NAC-0.53-fold, placebo +0.71-fold; 95% confidence interval -2.11 to-0.35; P < 0.05) and healing (NAC [100%], placebo [46%]; P < 0.01) between study treatments.

CONCLUSIONS

Postoperative NAC administration may improve amputation stump perfusion and healing in patients with CLTI and tissue perfusion defects at the time of amputation. Intraoperative laser-assisted fluorescent angiogra-phy may help surgeons identify high-risk patients with stump perfusion defects and provide early adjunctive interventions. Future studies can further explore the therapeutic benefits of NAC in the healing and perfusion of other surgical operative sites in high-risk individuals.

TRIAL REGISTRATION

clinicaltrials.gov, Identifier: NCT03253328.

N-Acetyl Cysteine as a Neuroprotective Agent in Progressive Multiple Sclerosis (NACPMS) trial: Study protocol for a randomized, double-blind, placebo-controlled add-on phase 2 trial

INTRODUCTION

Patients with progressive multiple sclerosis (PMS) experience relentless disability worsening. Current approved therapies have very modest effects on disability progression and purely focus on immunomodulation. While some inflammatory processes exist in non-active PMS, other biological processes such as neuronal injury from oxidative stress are likely more critical. N-acetyl cysteine (NAC) directly scavenges free radicals and restores neuronal glutathione, a major endogenous antioxidant. Our group has recently evaluated the safety of high dose NAC in a pilot trial in PMS with no tolerability concerns. We aim now to assess the safety, tolerability, and effect of NAC on progression of several MRI, clinical and biological markers in PMS patients.

METHODS

The NACPMS trial is a multi-site, randomized, double-blind, parallel-group, placebo-controlled add-on phase 2 trial. Ninety-eight PMS patients with EDSS 3.0-7.0 and aged 40-70 years will be randomized to NAC 1200 mg TID or matching placebo (1:1) as an add-on to the standard of care stratified by site and disease type during a 15-month intervention period. It is hypothesized that a reduction in oxidative stress injury will lessen brain atrophy estimated by MRI. The primary outcome analysis will compare the percent change over 12 months (Month 15 vs Month 3) between treatment and control arms using multivariable linear regression adjusted by age, sex, and disease duration.

ETHICS

This study was approved by the Institutional Review Board at the University of California, San Francisco (IRB21-34143), and an Investigational New Drug approval was obtained from the FDA (IND127184).

TRIAL REGISTRATION

NCT05122559.

Oral N-acetylcysteine as an adjunct to standard medical therapy improved heart function in cases with stable class II and III systolic heart failure

BACKGROUND

This research attempted to assess whether N-acetylcysteine (NAC) as adjunctive therapy can be useful in the treatment of patients with heart failure (HF).

METHODS

Fifty-five cases with diagnosed systolic HF and stable symptomatic New York Heart Association (NYHA) functional class II and III and on optimal medical treatment of HF for at least 3 months were assigned for receiving oral NAC (600 mg twice daily) or placebo for 12 weeks. The outcomes were changes in the echocardiographic hemodynamic indices as well as the patients' functional capacity assessed by NYHA classification over a 12-week treatment.

RESULTS

Compared to placebo, NAC more significantly improved the systolic left ventricular (LV) function expressed as the ejection fraction and Tei index. These changes are accompanied by more improvement in other LV echocardiographic indices including LV end-diastolic volume index and LV global longitudinal strain in the patients receiving NAC in comparison with those receiving placebo. In parallel with the improvement of LV function, right ventricular (RV) function expressed as RV fractional area change and RV Tei-index also got more improvement in those receiving NAC than those receiving placebo. However, the change in RV global longitudinal strain did not show a significant difference between study groups. Additionally, at week 12, the distribution of the NYHA functional class also shifted toward a better outcome in the NAC group in comparison with the placebo group; however, it was not significant.

CONCLUSIONS

These preliminary data support experimental findings showing that NAC supplementation is able to improve heart function.

TRIAL REGISTRATION

The registration of the trial was done at the Iranian Registry of Clinical Trials ( www.irct.ir ). Identifier code: IRCT20120215009014N333. Registration date: 2020-01-11.

N-Acetylcysteine: A Review of Clinical Usefulness (an Old Drug with New Tricks)

OBJECTIVE

To review the clinical usefulness of N-acetylcysteine (NAC) as treatment or adjunctive therapy in a number of medical conditions. Use in Tylenol overdose, cystic fibrosis, and chronic obstructive lung disease has been well documented, but there is emerging evidence many other conditions would benefit from this safe, simple, and inexpensive intervention. Quality of Evidence. PubMed, several books, and conference proceedings were searched for articles on NAC and health conditions listed above reviewing supportive evidence. This study uses a traditional integrated review format, and clinically relevant information is assessed using the American Family Physician Evidence-Based Medicine Toolkit. A table summarizing the potential mechanisms of action for N-acetylcysteine in these conditions is presented. Main Message. N-acetylcysteine may be useful as an adjuvant in treating various medical conditions, especially chronic diseases. These conditions include polycystic ovary disease, male infertility, sleep apnea, acquired immune deficiency syndrome, influenza, parkinsonism, multiple sclerosis, peripheral neuropathy, stroke outcomes, diabetic neuropathy, Crohn's disease, ulcerative colitis, schizophrenia, bipolar illness, and obsessive compulsive disorder; it can also be useful as a chelator for heavy metals and nanoparticles. There are also a number of other conditions that may show benefit; however, the evidence is not as robust.

CONCLUSION

The use of N-acetylcysteine should be considered in a number of conditions as our population ages and levels of glutathione drop. Supplementation may contribute to reducing morbidity and mortality in some chronic conditions as outlined in the article.

Antioxidant effects of N-acetylcysteine on the male reproductive system: A systematic review

This study aimed to evaluate the effect of N-acetyl cysteine on the male reproductive system and consensus and classification of data found from previous studies. It is undeniable that N-acetyl cysteine as a powerful antioxidant compound can medicate many diseases such as cardiovascular, kidney, liver and reproductive system disorders. With the increasing environmental pollution that has a direct adverse effect on male fertility, the use of this compound is able to positively function on human fertility health. In this study, we have been collected the main data of scientific articles (1994-2020) about N-acetyl cysteine effects. By searching in the scientific databases of PubMed, Google Scholar, Science Direct, Wiley and Web of Science, related articles were extracted. As a result, all observations have confirmed that N-acetyl cysteine can improve and normalise the spermatogenesis in the male reproduction system.

Progression of heart failure is attenuated by antioxidant therapy with N-acetylcysteine in myocardial infarcted female rats

This study investigated the therapeutic potential of N-acetylcysteine (NAC) in the treatment of heart failure in female rats. Myocardial infarcted (MI) rats were given NAC (250 mg/kg/day p.o.) during 28 days after surgery (MI + NAC) or vehicle (MI + Placebo), and sham-operated rats received the same treatments (Sham + NAC and Sham + Placebo). Electrocardiographic and echocardiographic analyses were performed in the last week of treatment. Cardiac mRNA levels of types I and II superoxide dismutase (SOD), catalase, types I and III glutathione peroxidase (GPX), nerve growth factor (NGF), β1-adrenergic receptor (β1ADR), and type 2 muscarinic receptor (M2R) were assessed. Cardiac levels NADPH oxidase (NOX) activity_, total content of reduced thiols, and SOD, GPX, and catalase activity were assessed. Compared to MI + Placebo group, MI + NAC group exhibited decreased NOX activity, increased content of reduced thiols, increased GPX activity, and normalized GPX III mRNA levels (p < 0.05). Heart and lung weights, left ventricular (LV) end-diastolic volume and left atrium/aorta ratio were decreased, while LV posterior wall thickness and ejection fraction were increased in MI + NAC group versus MI + Placebo rats (p < 0.05). Power density of low frequency band was decreased, while power density of high frequency and the root mean square of the successive differences were increased in MI + NAC rats versus MI + Placebo (p < 0.05). These findings indicate that NAC promotes therapeutic effects in the progression of MI-induced heart failure in female rats.

Cysteine/Glutathione Deficiency: A Significant and Treatable Corollary of Disease

Glutathione (GSH) deficiency may play a pivotal role in a variety of apparently unrelated clinical conditions and diseases. Orally administered N-acetylcysteine (NAC), which replenishes the cysteine required for GSH synthesis, has been tested in a large number of randomized placebo-controlled trials involving these diseases and conditions. This chapter focused on developing a base of evidence suggesting that NAC administration improves disease by increasing cysteine and/or GSH in a variety of diseases, thereby implying a significant role for GSH deficiency in the clinical basis of many diseases. To develop this base of evidence, we systematically selected studies which considered the hypothesis that the therapeutic efficacy for NAC is an indication that cysteine and/or GSH deficiency is a pathophysiological part of the diseases studied. In this manner we focus this chapter on explaining the biological mechanisms of NAC therapy in a wide variety of disorders and demonstrate its ubiquitous role in improving disease that involves disrupted GSH and/or cysteine metabolism.

Advanced Oxidation Protein Products-Modified Albumin Induces Differentiation of RAW264.7 Macrophages into Dendritic-Like Cells Which Is Modulated by Cell Surface Thiols

Local accumulation of Advanced Oxidation Protein Products (AOPP) induces pro-inflammatory and pro-fibrotic processes in kidneys and is an independent predictor of renal fibrosis and of rapid decline of eGFR in patients with chronic kidney disease (CKD). In addition to kidney damage, circulating AOPP may be regarded as mediators of systemic oxidative stress and, in this capacity, they might play a role in the progression of atherosclerotic damage of arterial walls. Atherosclerosis is a chronic inflammatory disease that involves activation of innate and adaptive immunity. Dendritic cells (DCs) are key cells in this process, due to their role in antigen presentation, inflammation resolution and T cell activation. AOPP consist in oxidative modifications of proteins (such as albumin and fibrinogen) that mainly occur through myeloperoxidase (MPO)-derived hypochlorite (HOCl). HOCl modified proteins have been found in atherosclerotic lesions. The oxidizing environment and the shifts in cellular redox equilibrium trigger inflammation, activate immune cells and induce immune responses. Thus, surface thiol groups contribute to the regulation of immune functions. The aims of this work are: (1) to evaluate whether AOPP-proteins induce activation and differentiation of mature macrophages into dendritic cells in vitro; and (2) to define the role of cell surface thiol groups and of free radicals in this process. AOPP-proteins were prepared by in vitro incubation of human serum albumin (HSA) with HOCl. Mouse macrophage-like RAW264.7 were treated with various concentrations of AOPP-HSA with or without the antioxidant N-acetyl cysteine (NAC). Following 48 h of HSA-AOPP treatment, RAW264.7 morphological changes were evaluated by microscopic observation, while markers of dendritic lineage and activation (CD40, CD86, and MHC class II) and allogeneic T cell proliferation were evaluated by flow cytometry. Cell surface thiols were measured by AlexaFluor-maleimide binding, and ROS production was assessed as DCF fluorescence by flow cytometry. HSA-AOPP induced the differentiation of RAW264.7 cells into a dendritic-like phenotype, as shown by morphological changes, by increased CD40, CD86 and MHC class II surface expression and by induction of T cell proliferation. The cell surface thiols dose dependently decreased following HSA-AOPP treatment, while ROS production increased. NAC pre-treatment enhanced the amount of cell surface thiols and prevented their reduction due to treatment with AOPP. Both ROS production and RAW264.7 differentiation into DC-like cells induced by HSA-AOPP were reduced by NAC. Our results highlight that oxidized plasma proteins modulate specific immune responses of macrophages through a process involving changes in the thiol redox equilibrium. We suggest that this mechanism may play a role in determining the rapid progression of the atherosclerotic process observed in CKD patients.

Contrast-induced neurotoxicity after coronary angiography

BACKGROUND

Contrast-induced neurotoxicity (CIN) is a very rare complication of coronary angiography. Clinical presentations include encephalopathy, seizures, cortical blindness, and focal neurological deficits. An inherent difficulty in understanding the natural history of the condition as well as its risk factors and prognosis is the rarity of its occurrence. To date, there are only case reports published on this complication.

PATIENTS AND METHODS

This was a retrospective analysis of 9 patients with CIN (8 men, 1 woman; mean age, 64.6 ± 7.8 years; range, 47-72 years) and coronary artery disease who were administered iopromide contrast agent.

RESULTS

In the last 3 years, we diagnosed 9 patients with CIN. Of these, 8 patients (89 %) had hypertension. The clinical presentations of the patients were different on admission: 6 patients had acute coronary syndrome and 3 patients had stable angina pectoris. One patient had history of previous contrast agent exposure. All patients underwent coronary angiography with a low-osmolar nonionic monomer contrast agent (iopromide; Ultravist®-300, Bayer Healthcare). The mean volume of contrast injected was 177 ± 58 ml. The mean time between contrast agent administration and clinical symptoms was 100 ± 71 min (range, 30-240 min). While in 5 of the patients (56 %) the clinical sign of CIN was confusion, 2 had ophthalmoplegia, 1 had cerebellar dysfunction, and 1 had monoplegia. In 8 of 9 patients (89 %), neurological symptoms resolved after giving supportive medication and hydration. Only 1 female patient, who had bilateral ophthalmoplegia, did not recover. Neurological recovery occurred at a mean time of 14.2 ± 6.7 h (range, 8-30 h).

CONCLUSION

CIN is a very rare condition. Advanced age, male gender, and hypertension are the greatest risk factors for CIN. Although the prognosis of CIN is benign, it can potentially cause permanent neurological deficits or death. We found that patients with ophthalmic involvement had a higher propensity for persistent deficit. On the basis of the current data, we propose 170 ml as the maximal recommended dose for coronary procedures.

N-acetylcysteine-induced headache in hospitalized patients with acute acetaminophen overdose

Intravenous N-acetylcysteine (IV-NAC) is usually regarded as a safe antidote to acetaminophen overdose. However, during infusion of the loading dose, adverse drug reactions such as a headache may occur. The objectives of this study were to investigate the prevalence of headache in patients presenting to hospital after acetaminophen overdose and to determine which clinical findings are most predictive of headache among these patients. This is a retrospective cohort study of hospital admissions for acute acetaminophen overdose that was conducted over a period of 4 years from January 1, 2005 to December 31, 2008. Demographic data, clinical characteristics, and predictors of headache were analyzed. spss 15 was used for data analysis. Two-hundred and fifty-five patients were studied; their mean age was 23.1 ± 1.6; 83.9% of them were women and 14.9% had a headache during hospitalization. Headache among patients was significantly associated with IV-NAC administration (P = 0.001), intentional ingestion of drug (P = 0.04), acetaminophen concentration above 'possible toxicity' treatment line (P = 0.04), a high acetaminophen concentration (P = 0.04), and a long hospital stay (P = 0.03). Multiple logistic regression showed a significant risk factor for headache in patients administered IV-NAC (P = 0.04). We recorded a high frequency of headache in patients with acute acetaminophen overdose in our geographical area. This study suggests that among those patients, the use of IV-NAC is associated with an increased risk of headache.

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.

Attenuated severity of new acute ischemic events in patients with previous coronary heart disease receiving long-acting nitrates

BACKGROUND

Platelet aggregation and secondary vasoconstriction are key events in the genesis of acute coronary syndromes.

HYPOTHESIS

Since nitrates have vasodilatory and antiaggregant effects, treatment with long-acting nitrates at the time of onset of acute coronary syndromes could be associated with attenuation of their severity.

METHODS

A consecutive series of 533 patients with acute coronary syndrome and past history of coronary artery disease admitted to the Cardiology Service of a general hospital was studied. A specific questionnaire assessed the use of nitrates and other relevant drugs, as well as other clinical variables. The diagnosis of unstable angina or acute myocardial infarction (MI) was established according to clinical, electrocardiographic, and enzymatic criteria.

RESULTS

In the whole cohort, 169 patients had MI and 364 had unstable angina. Previous use of long-acting nitrates was significantly more common in patients with unstable angina (56%) than in those with MI (37%) (p < 0.0001). Multivariate analysis identified being a nonsmoker [odds ratio: 95%, confidence limits (CL) 0.37, 0.23-0.59], previous unstable angina (CL 0.62, 0.41-0.92), use of aspirin (CL 0.58, 0.41-0.92), and use of long-acting nitrates (CL 0.61, 0.40-0.93) as the independent predictors of the development of unstable angina rather than MI; of these the combination of nitrates and aspirin was the strongest predictor.

CONCLUSIONS

Long-acting nitrates as well as aspirin are suggested to have a protective or modifying effect on the development of acute coronary syndromes, favoring unstable angina rather than acute MI.

N-acetylcysteine improves microcirculatory flow during smoking: new effects of an old drug with possible benefits for smokers

BACKGROUND

Cigarette smoking provokes marked acute changes in the microcirculatory vasculature, including a reduced blood flow velocity. In accordance with the hypothesis that the reduced blood flow is due to an imbalance between pro-oxidants and oxidants, we recently showed that most of the reduction could be reversed by a high dose of vitamin C.

HYPOTHESIS

In the present work we tested the hypothesis that N-acetylcysteine, a mucolyticum and an antioxidant, may have an effect on the smoking-induced changes observed by vital capillary microscopy of the nailfold.

METHODS

In all, 37 healthy volunteers of both genders and with varied smoking habits were treated with N-acetylcysteine 200 mg t.i.d. for 2 weeks. In vivo investigation of the microcirculation by capillaroscopy was performed before and after treatment.

RESULTS

Treatment with N-acetylcysteine significantly reduced the smoking-induced relative decrease in capillary blood flow velocity in a group of volunteers with varied smoking habits (p = 0.0016). The preventive effect was clearly significant in smokers (p = 0.003).

CONCLUSION

Treatment with N-acetylcysteine has a positive impact on microcirculatory flow during smoking, particularly in habitual smokers.

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.

N-Acetylcysteine in nephrology; contrast nephropathy and beyond

PURPOSE OF REVIEW

Since the first publication appeared in 2000 showing that prophylactic oral administration of the antioxidant acetylcysteine, along with adequate hydration, can prevent the reduction in renal function induced by non-ionic, low-osmolality contrast agents, acetylcysteine has rapidly become widely used in clinical practice. Meanwhile, other applications of acetylcysteine in nephrology have been reported. This review analyses recent literature on the effects of acetylcysteine on radiocontrast-induced nephropathy, on plasma homocysteine concentrations, and on cardiovascular events in patients with end-stage renal failure.

RECENT FINDINGS

At least 19 randomized trials evaluating acetylcysteine for the prevention of radiocontrast-induced nephropathy, at least five meta-analyses, and several reviews on that topic have been published within the past 4 years. The studies on radiocontrast-induced nephropathy showed remarkably mixed results, probably as a result of study heterogeneity. One study recently indicated that the administration of acetylcysteine during a haemodialysis session significantly lowered plasma homocysteine concentrations. Another study indicated that long-term antioxidative treatment with acetylcysteine significantly reduced cardiovascular events in patients with end-stage renal failure.

SUMMARY

Although there are controversies on dosing and timing, the use of acetylcysteine together with hydration should be considered to protect patients from radiographic contrast media-induced nephropathy. Long-term antioxidative treatment with acetylcysteine in patients with end-stage renal failure may also be useful to prevent adverse cardiovascular events.

Association between vascular tolerance and platelet upregulation: comparison of nonintermittent administration of pentaerithrityltetranitrate and glyceryltrinitrate

Enhanced formation of oxygen-derived radicals O plays a dominant role in the development of nitrate tolerance. In 18 healthy subjects, this study tested the effect of additional vitamin C (Vit-C) administration (1 g three times daily) on glyceryltrinitrate (GTN)-induced hemodynamic changes during 3 days of nonintermittent transdermal administration of GTN (0.4 mg/h) in comparison with administration of pentaerithrityltetranitrate (PETN, 40 mg three times daily, orally). GTN caused an immediate significant rise in arterial conductivity (a/b ratio of dicrotic pulse pressure, from 2.33 +/- 0.06 to 2.52 +/- 0.06). Within 2 days of GTN administration, the a/b ratio progressively decreased and reached pre-GTN control levels, documenting tolerance. However, the administration of GTN along with Vit-C or with PETN alone induced changes in the a/b ratio and in the orthostatic reaction, which were fully maintained for the period of treatment. This vascular tolerance seen after GTN treatment was paralleled by an upregulation of ex vivo platelet activity, which was evident from a rise in aggregation from 29.2 +/- 2.8% at control day to 85.4 +/- 8.5% at day 3, and additionally from thrombin-induced increases of intracellular Ca concentration from 494 +/- 60 nM at control day to 741 +/- 37 nM at day 3. This upregulation was not observed during PETN or GTN; with additional Vit-C administration. Administration of PETN or GTN, the latter supplemented by Vit-C, induced neither vascular tolerance nor the upregulation of washed platelet activity during nonintermittent administration, in contrast to GTN without Vit-C. This is explained by a diminished formation of reactive oxygen species when PETN or when GTN along with Vit-C is used.

Acetylcysteine and contrast media nephropathy

PURPOSE OF REVIEW

Radiographic contrast media are used at an increasing rate for several diagnostic and therapeutic applications. Therefore, contrast agent-induced nephropathy will become more important, including the risk of patient impairment and costs. The prevention of radiographic contrast-induced nephropathy is mandatory. Radiographic contrast agent-induced nephropathy is caused by vasoconstriction-mediated renal medullary ischaemia and direct toxic damage to renal tubular epithelial cells. These effects may be partly mediated by the generation of reactive oxygen species. Data from experimental studies indicate that antioxidants, e.g. acetylcysteine, may prevent radiocontrast-induced nephropathy.

RECENT FINDINGS

Two prospective, randomized, placebo-controlled studies in patients with moderate renal insufficiency confirmed that the prophylactic oral administration of acetylcysteine, at a dose of 600 mg twice a day along with hydration, prevents the reduction in renal function after radiocontrast administration.

SUMMARY

The use of acetylcysteine together with hydration is the treatment of choice to protect against radiographic contrast media-induced nephropathy.

[Tolerability and efficiency of a new transdermic nitroglycerin patch in outpatients with chronic stable angina. The PATRICH Trial]

OBJECTIVE

To obtain data on local and systemic tolerability of three different doses (5 mg/24 h, 10 mg/24 h, and 15 mg/24 h) of a new model of nitroglycerin patch (Trinipatch, Sanofi-Synthelabo, S. A.) in patients with chronic stable angina.

METHODS

A total of 954 patients were studied for a follow-up period of 12 weeks. Patients were distributed as follows: 132 to the 5 mg/24 h patch, 727 to the 10 mg/24 h patch, and 95 to the 15 mg/24 h patch. The local tolerability was evaluated by using the Draize scale and the systemic tolerability by recording the adverse reactions and assessing the effect on blood pressure. Furthermore, the efficiency of therapy was evaluated by means of the variations observed in the number and severity of angina crises, as well as the weekly use of sublingual nitroglycerine.

RESULTS

Ninety-four patients (9.8%) showed signs of cutaneous irritation. Thirty-two patients (3.3%) showed erythema, and one patient (0.1%) showed erythema and induration. Thirty-nine patients (4.1%) had some type of systemic adverse reaction during the study. A total of 44 adverse reactions were recorded, headache being the most common (79.5%). Only one severe adverse reaction was observed (mild heart failure), which in the opinion of the researcher was not related to the medication. No dropouts were recorded on account of adverse reactions. The number of patients with angina crises and the number of weekly angina crises decreased significantly with therapy.

CONCLUSIONS

The transdermic nitroglycerin patch was demonstrated to be a safe and well tolerated therapy for chronic stable angina, both in terms of local and systemic tolerability. Moreover, its efficiency was demonstrated as the number of angina crises decreased significantly.

N-acetylcysteine in acute cardiology: 10 years later: what do we know and what would we like to know?!

N-acetylcysteine (NAC) is known in a variety of branches of medicine. This paper addresses in detail the action of NAC as it is emerging from research and clinical trials over the past decade in cardiology, giving rise to new concepts. The result is a process resembling creation of a mosaic from individual pieces. Also, the role of NAC in acute cardiology, during acute reperfusion in particular, is defined.

Coagulation indicators in chronic stable effort angina and unstable angina: relationship with acute phase reactants and clinical outcome

The aim of the study was to evaluate which pattern of coagulation indicators characterizes unstable angina and, particularly, its relationship with short-term prognosis. Forty patients with unstable angina (UA Group) at admission in the intensive care unit, 40 patients with chronic stable effort angina (SEA Group), and 20 age- and sex-matched healthy controls were studied. Blood coagulation indicators were fibrinogen, prothrombin fragment F1 + 2 (F1 + 2), thrombus precursor protein (TpP), and D-dimer. C reactive protein (CRP) and cardiac Troponin I (cTnI) have also been determined and compared. Patients in the UA Group were followed for in-hospital adverse events (sudden death, acute myocardial infarction and angina refractory to medical therapy). CRP, D-dimer and cTnI plasma levels were significantly lower in the SEA Group than in the UA Group; the same trend was found for fibrinogen and F1 + 2 plasma levels, although not statistically significant. The TpP was similar in all groups. The control group showed the lowest levels for all indicators. Within the UA Group, 17 patients developed adverse events during hospitalization; F1 + 2, D-dimer, cTnI and CRP plasma levels were higher in these patients than in those with good outcome. Relative risks for adverse events associated with the highest tertile of D-dimer, cTnI, and CRP plasma levels were 8.4 (95% confidence interval, 1.5-48.9), 6.7 (95% confidence interval, 1.1-38.6) and 5.2 (95% confidence interval, 1.1-25.2), respectively. D-Dimer is significantly increased in patients with unstable angina and, in particular, in those who develop an adverse event.

Platelet-dependent thrombin generation in patients with unstable angina pectoris

Platelet-dependent thrombin generation was assessed during both unstable and stable periods in 59 patients with unstable angina and at rest in 31 healthy controls. Thrombin generation during the unstable period was significantly greater than that at rest in the healthy control group (p < 0.0001) and that during the stable period (p < 0.0001). Changes in thrombin generation were related to the time after onset of unstable angina, not to degree of improvement in the severity of coronary stenosis.