Effects of nonionic versus ionic contrast media on complications of percutaneous transluminal coronary angioplasty

Intra-procedural arrhythmia during cardiac catheterization: A systematic review of literature

BACKGROUND

Cardiac catheterization is among the most performed medical procedures in the modern era. There were sporadic reports indicating that cardiac arrhythmias are common during cardiac catheterization, and there are risks of developing serious and potentially life-threatening arrhythmias, such as sustained ventricular tachycardia (VT), ventricular fibrillation (VF) and high-grade conduction disturbances such as complete heart block (CHB), requiring immediate interventions. However, there is lack of systematic overview of these conditions.

AIM

To systematically review existing literature and gain better understanding of the incidence of cardiac arrhythmias during cardiac catheterization, and their impact on outcomes, as well as potential approaches to minimize this risk.

METHODS

We applied a combination of terms potentially used in reports describing various cardiac arrhythmias during common cardiac catheterization procedures to systematically search PubMed, EMBASE and Cochrane databases, as well as references of full-length articles.

RESULTS

During right heart catheterization (RHC), the incidence of atrial arrhythmias (premature atrial complexes, atrial fibrillation and flutter) was low (< 1%); these arrhythmias were usually transient and self-limited. RHC associated with the development of a new RBBB at a rate of 0.1%-0.3% in individuals with normal conduction system but up to 6.3% in individuals with pre-existing left bundle branch block. These patients may require temporary pacing due to transient CHB. Isolated premature ventricular complexes or non-sustained VT are common during RHC (up to 20% of cases). Sustained ventricular arrhythmias (VT and/or VF) requiring either withdrawal of catheter or cardioversion occurred infrequently (1%-1.3%). During left heart catheterizations (LHC), the incidence of ventricular arrhythmias has declined significantly over the last few decades, from 1.1% historically to 0.1% currently. The overall reported rate of VT/VF in diagnostic LHC and coronary angiography is 0.8%. The risk of VT/VF was higher during percutaneous coronary interventions for stable coronary artery disease (1.1%) and even higher for patients with acute myocardial infarctions (4.1%-4.3%). Intravenous adenosine and papaverine bolus for fractional flow reserve measurement, as well as intracoronary imaging using optical coherence tomography have been reported to induce VF. Although uncommon, LHC and coronary angiography were also reported to induce conduction disturbances including CHB.

CONCLUSION

Cardiac arrhythmias are common and potentially serious complications of cardiac catheterization procedures, and it demands constant vigilance and readiness to intervene during procedures.

Coronary Angioplasty Using a Low Osmolar Nonionic Contrast Medium

This study was performed to investigate the occurrence of acute angiographic and clinical complications following PTCA using a low osmolar nonionic contrast medium. Five hundred consecutive PTCA procedures were analyzed retrospectively. The incidence of acute in-laboratory complications during PTCA as well as complications occurring during the hospital stay 24 to 48 hours after the procedure were recorded. Occlusion of the dilated artery or a side branch was observed in 19 (3.8%) of the procedures, major dissection in 34 (6.8%), and thrombus in 14 (2.8%). One patient died, 6 (1.2%) required emergency coronary artery bypass grafting (CABG), 4 (0.8%) required an emergency PTCA, and 7 (1.4%) suffered myocardial infarction (MI). Our results show that angiographic findings of thrombus, major dissection and occlusion were serious conditions that related to the clinical complications MI, emergency CABG and re-PTCA. Patients with unstable angina were risk patients for both angiographic and clinical complications. Low rates of intraarterial thrombus formation and coronary artery occlusion indicate good angiographic technique and anticoagulant and antiplatelet medication.

Dopamine-1 Receptor Agonist: Renal Effects and Its Potential Role in the Management of Radiocontrast-Induced Nephropathy

Radiocontrast-induced nephropathy remains the third leading cause of hospital-acquired acute renal failure. Once established, this syndrome is associated with increased morbidity and mortality as well as increased health care costs. Recently, studies have been initiated to evaluate the potential of a selective dopamine-1 receptor agonist (fenoldopam) in ameliorating radiocontrast-induced renal failure. Selective dopamine-1 receptor agonists exhibit many desirable renal effects that support their use for the prophylaxis of radiocontrast-induced nephropathy, including decreases in renal vascular resistance and increases in renal blood flow, glomerular filtration, and sodium and water excretion. Several reports have documented a beneficial effect of fenoldopam administration in attenuating radiocontrast-induced nephropathy. In contrast, a recent multicenter, randomized study did not demonstrate a renoprotective effect of fenoldopam against radiocontrast-induced nephropathy. The presence of multiple confounders, however, precludes a definitive conclusion regarding the ability of fenoldopam to protect against radiocontrast-induced nephropathy. Additional studies are needed to properly evaluate the role of fenoldopam in radiocontrast-induced nephropathy prophylaxis.

Contrast media and clotting: what is the evidence?

The rapid development of percutaneous coronary and peripheral vascular interventional technologies and also noninvasive imaging systems has led to a dramatic increase in the number of patients receiving contrast media (CM). Although relatively uncommon, adverse events can occur following administration of contrast, including nuisance reactions (e.g., nausea and urticaria) and potentially severe complications, such as contrast-induced nephropathy and thrombotic events. In this report, we review the evidence regarding the occurrence of thrombotic effects following iodinated CM administration during percutaneous coronary intervention.

MR contrast agents: Physical and pharmacologic basics

Since approval of the first magnetic resonance (MR) contrast agent was granted in 1988, there has been remarkable growth in the utilization of intravenous gadolinium (Gd)-based agents. Currently it is estimated that nearly half of all MR studies performed are contrast-enhanced. Despite containing a toxic heavy metal, these agents have proven to be not only an effective diagnostic adjunct to non-enhanced MRI, but also remarkably well tolerated and safe. As a result, conventional wisdom has been that MR contrast media are "biologically inert," a notion that is clearly false. Ultimately, it is the radiologist's responsibility to understand the potential adverse effects of Gd-based agents and the special situations in which they are likely to occur; however, the basic pharmacology of contrast agents is generally not included in medical school curricula or formally taught in residency. The purpose of this review is to discuss the mechanism of action of MR contrast agents and relevant aspects of their clinical pharmacology, including effects on the cardiovascular and renal systems, potential laboratory errors, and special situations involving women and children. We also briefly discuss the issue of nephrogenic systemic fibrosis (NSF).

Cardiac events after low osmolar ionic or isosmolar nonionic contrast media utilization in the current era of coronary angioplasty

OBJECTIVES

Our study aimed to compare the isosmolar nonionic dimer iodixanol and the low osmolar ionic agent ioxaglate in the current era of percutaneous coronary intervention (PCI), using clopidogrel, enoxaparine, direct stenting, and drug eluting stent.

BACKGROUND

Previous studies have suggested an association between thrombus-related events and type of contrast media.

METHODS

Our prospective single-center study included 498 consecutive patients who were assigned to receive either iodixanol (n = 231) or ioxaglate (n = 267). The primary endpoint was the cumulative rate of in-hospital major adverse clinical events (MACE). A secondary endpoint was the rate of angiographic or procedural complications.

RESULTS

Clinical and angiographic baseline characteristics and procedural data were similar in the 2 groups. A peak anti-Xa > 0.5 IU/ml was obtained in 97% in both groups. Glycoprotein IIb/IIIa inhibitors were used in 42% of patients. Coronary stenting was performed in 91% of patients, with direct stenting in 70%, and drug-eluting stent in 28% of patients. In-hospital MACE was more frequent in patients receiving iodixanol compared with those receiving ioxaglate (4.8% vs. 0.3%, P < 0.005). This difference was mainly related to the appearance of a large thrombus during PCI (6% with iodixanol vs. 0.3% with ioxaglate, P < 0.0001). In multivariate analysis, independent predictors of in-hospital MACE were use of iodixanol (P < 0.01), the higher number of stent used (P < 0.008), bifurcation/ostial lesion (P < 0.01), and balloon dilation before stenting (p < 0.001).

CONCLUSIONS

In our study reflecting the current era of PCI, thrombus-related events are more frequent with the isosmolar nonionic dimer iodixanol than with the low osmolar ionic agent ioxaglate.

Adverse Reactions of Low Osmolar Non-Ionic and Ionic Contrast Media When Used Together or Separately During Percutaneous Coronary Intervention

BACKGROUND

Due to perceived advantages in the use of non-ionic contrast agents for diagnostic angiography and ionic agents for percutaneous coronary intervention (PCI), patients often receive various combinations of both types of agents.

AIM

To assess potential adverse effects of non-ionic and ionic contrast media when used together or separately during percutaneous coronary intervention.

METHODS

We retrospectively evaluated the outcomes of 532 patients undergoing percutaneous coronary intervention in our institution. Patients were divided into two groups: those that underwent diagnostic angiography and "follow on" PCI; and those that underwent "planned" PCI. The groups were subdivided on the basis of the use of the ionic agent ioxaglate or the non-ionic agent iopromide during PCI. The frequency of allergic reactions and major adverse cardiac events (MACE) were noted.

RESULTS

With respect to the "follow on" group, allergic reactions occurred in 9 of 150 patients (6.0%) who received the combination of ioxaglate and iopromide versus 1 of 93 (1.1%) who only received iopromide (p=0.094). There was no difference with respect to MACE [6 (4.0%) ioxaglate and iopromide versus 4 (4.3%) iopromide alone, p=1.00]. In the "planned" group, 7 of 165 patients (4.2%) receiving ioxaglate had an allergic reaction as opposed 0.0% (0 of 124 patients) in the iopromide group (p=0.021). All contrast reactions were mild. The incidence of a MACE was similar in both groups [1 (0.6%) ioxaglate versus 2 (1.6%) iopromide, p=0.579]. The incidence of allergic reactions was similar if ioxaglate was used alone or in combination with iopromide (p=0.478).

CONCLUSIONS

Whilst combining ionic and non-ionic contrast agents in the same procedure was not associated with any more adverse reactions than using an ionic contrast agent alone, the ionic contrast agent ioxaglate was associated with the majority of allergic reactions. With respect to choice of contrast agent, using the non-ionic agent iopromide alone for coronary intervention is associated with the lowest risk of an adverse event.

Comparative tolerability of contrast media used for coronary interventions

Radiographic contrast media (CM) are necessary to provide x-ray absorption of the bloodstream; all other observed effects need to be regarded as adverse. Four types of CM are currently used in diagnostic and interventional cardiology: ionic high-osmolar CM (HOCM), either ionic or non-ionic low-osmolar CM (LOCM), and non-ionic iso-osmolar CM (IOCM). Focusing on the potential cardiovascular effects caused by the CM, there is a clear difference between HOCM and the LOCM or IOCM. HOCM have a poorer profile due to a higher incidence of hypotension and electrophysiological effects. To prevent contrast-induced nephropathy, HOCM should be avoided and patients should receive the minimal dose of LOCM or IOCM with intravenous hydration before and after the procedure. Clinical hyperthyroidism has been detected after CM use, but the condition appears, ultimately, to be self-limited and to occur mainly in elderly patients. When assessing the need for a CM in terms of improved patient safety, preventing serious complications should be the major factor determining the choice. CM should not be selected on the basis of minor adverse effects since these are, ultimately, of low clinical relevance. Thrombotic events, in contrast, carry a high clinical relevance and we consider that these should be the main issue governing current choice. Ionic LOCM appear to have better profile than other CM with respect to interaction with platelet function and coagulation. In relation to thrombotic events in randomised clinical studies, ionic CM have been associated, mainly, with favourable and some neutral results compared with non-ionic agents. Only one trial indicated a more pronounced antithrombotic effect of the non-ionic IOCM relative to the ionic LOCM. The antithrombotic advantages of ionic over non-ionic LOCM are, in part, balanced by a greater frequency of minor adverse effects such as nausea, vomiting or cutaneous rashes. A matter of concern is the delayed adverse effects observed with non-ionic IOCM. However, severe and life-threatening reactions are exceptional and there are probably no significant differences between IOCM and LOCM whether ionic or non-ionic. However, in patients with known allergies, non-ionic CM are to be recommended. On the basis of the available pre-clinical and clinical data, the ionic LOCM or the non-ionic IOCM are the agents to be recommended in percutaneous coronary interventions because of their antithrombotic advantages over non-ionic LOCM.

A randomized prospective trial of ioxaglate 320 (Hexabrix) vs. iodixanol 320 (Visipaque) in patients undergoing percutaneous coronary intervention

We performed a randomized, prospective, double blind trial comparing the use of the ionic dimer contrast agent ioxaglate 320 (Hexabrix) with the nonionic dimer contrast agent iodixanol 320 (Visipaque) in 618 patients undergoing percutaneous coronary intervention (PCI) for stable or unstable coronary artery syndromes. The aim was to determine whether the different anticoagulant and antiplatelet properties of these two contrast agents resulted in a significant difference in the incidence of a combined endpoint comprising the major complications of PCI. Procedural success rates were marginally higher in the Visipaque group compared to the Hexabrix group, although this did not reach statistical significance (96.7% vs. 93.9%; P = 0.09). There was a borderline statistically significant higher requirement for bailout stenting in the Visipaque group compared to the Hexabrix group (6.8% vs. 3.2%; P = 0.05), although this was not a predefined endpoint. The incidence of the combined primary endpoint of failed catheter laboratory outcome/requirement for bailout stenting/requirement for abciximab/myocardial infarction/death before hospital discharge was higher in the Visipaque group compared to the Hexabrix group (17.9% vs. 14.8%), although this did not reach statistical significance (P = 0.29). When subgroup analysis was performed, the incidence of the combined endpoint in patients with stable coronary artery disease randomized to receive either Visipaque or Hexabrix was identical (13.7%). In patients with an acute coronary syndrome, there was a trend toward a reduced incidence of the combined endpoint in the Hexabrix compared to the Visipaque group, although this did not reach statistical significance (17.2% vs. 24.8%; P = 0.17). More adverse reactions occurred in the Hexabrix group compared to the Visipaque group (8.7% vs. 4.9%; P = 0.06). We conclude that there is no clear advantage with the use of an ionic contrast agent in a large population of patients undergoing PCI for both stable and unstable coronary artery disease. Although the study was underpowered to detect significant differences with the use of either agent when patients with either stable or unstable coronary disease were studied, it is highly unlikely that the ionicity of the contrast agent confers any advantage for patients with stable coronary disease. There remains a possibility that ionic agents do have advantages for patients with unstable coronary artery disease undergoing PCI, although a larger study than ours would be required to confirm or refute this.

Do clinically relevant circulating concentrations of radiographic contrast agents inhibit platelet-dependent arterial thrombosis?

OBJECTIVES

The purpose of this study was to determine if radiographic contrast agents (RCAs) inhibit thrombosis in a rat carotid artery injury model.

BACKGROUND

Whether ionic and nonionic RCAs differentially affect thrombus formation during coronary artery angioplasty is controversial. Although there are numerous in vitro studies and clinical trials addressing this issue, it is unknown whether clinically relevant plasma concentrations of RCA inhibit platelet-dependent thrombosis after injury of medium-sized arteries.

METHODS

Rats received RCA or control solution by bolus (0.7 ml/kg) and constant (0.04 ml/kg/min) intravenous infusion. Carotid arteries were injured with ferric chloride. Blood flow was monitored for 1 h. In vitro platelet aggregation and plasma clotting were studied.

RESULTS

After injury, mean times free from formation of an occlusive, platelet-rich thrombus were 16.2+/-2.3, 49.6+/-18.9, 47.9+/-21.0, and 37.1+/-22.8 min for rats (n=5/group) that received saline, diatrizoate (P<.002 vs. saline), ioxaglate (P<.002 vs. saline), and iohexol (P=.06 vs. saline), respectively. Reperfusion after initial occlusion did not occur in saline-treated animals, but was common in rats that received RCA. The antithrombotic properties of RCA were not explained by their high osmolarities or by detectable effects on in vitro platelet aggregation and plasma clotting. Plasma concentrations of RCA were <1%.

CONCLUSIONS

Systemic administration of RCA at doses that achieve low, clinically relevant plasma concentrations can inhibit platelet-rich thrombus formation after arterial injury. Antithrombotic properties of ionic RCA appear to be greater than those of nonionic RCA.

Computer-assisted continuous ST-segment analysis for clinical research: methodological issues

Continuous ST-segment monitoring has been used to detect acute myocardial ischemia, determine the success of the reperfusion therapy, and predict outcomes in both research and a variety of clinical settings. However, analyzing the abundant electrocardiography (ECG) data recorded using continuous multilead ST-segment monitoring techniques is time consuming and requires expertise. Experienced data interpreters in dedicated ECG core laboratories handle many continuous ECG data records from large clinical trials. Little information on measurement issues for computer-assisted ST-segment analysis is available for individual investigators. Unsupervised or inexperienced computer analysis of ST-segment deviations can, under certain circumstances, yield invalid or unreliable summary indices. The goal of this article is to discuss basic ST-segment measurement principles in evaluating acute myocardial ischemia and methodological issues surrounding the use of computer-assisted ST-segment analysis for continuous ECG data. Variables affecting ST-segment measurements will be examined. Sources and examples of variability for these potential errors will be identified.

Impact of contrast agent type (ionic versus nonionic) used for coronary angiography on angiographic, electrocardiographic, and clinical outcomes following thrombolytic administration in acute myocardial infarction

The goal of this study was to examine the relationship between contrast agent type (ionic vs. nonionic) and angiographic, electrocardiographic, and clinical outcomes after thrombolytic administration. Ionic or nonionic contrast agents were selected in a nonrandomized fashion for 90-min angiography and percutaneous coronary intervention (PCI) following thrombolytic administration in the TIMI 14 trial [tissue plasminogen activator (tPA) or reteplase (rPA) vs. low-dose lytic + abciximab]. There was no relationship between contrast agent type and overall patency, rate of TIMI grade 3 flow, or corrected TIMI frame counts (CTFCs) in open culprit arteries and in post-PCI patency rates or post-PCI CTFCs. In patients treated with ionic contrast, ejection fractions at 90 min were slightly but significantly lower (56.2 +/- 16.5, n = 122, vs. 59.8 +/- 14.4, n = 322; P = 0.02), chest pain duration was longer (2.8 +/- 4.1 hr, n = 255, vs. 1.7 +/- 3.6, n = 550; P = 0.0003), and complete ST segment resolution was less frequent (41.5% vs. 50.8%; P = 0.04). While there was no difference in epicardial blood flow, ionic contrast agent use was associated with poorer ST segment resolution, longer chest pain duration, and poorer ejection fractions, perhaps as a result of microvascular dysfunction.

A comparison of ionic versus nonionic contrast medium during primary percutaneous transluminal coronary angioplasty for acute myocardial infarction (GUSTO IIb). Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes

The clinical impact of contrast medium selection during primary percutaneous transluminal coronary angioplasty for acute myocardial infarction (AMI) has not been studied. We compared the clinical outcomes of patients who received ionic versus nonionic low osmolar contrast medium in the setting of primary percutaneous transluminal coronary angioplasty for AMI in the second Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes (GUSTO IIb) trial. Univariable and multivariable analyses were performed to assess the relation between contrast medium selection and clinical outcome (death, reinfarction, or refractory ischemia) at 30 days. Although baseline clinical and angiographic characteristics were generally similar between the 2 groups, patients who received ionic, low osmolar contrast were less likely to have been enrolled at a US site (23% vs 43%, p = 0.001) and less likely to have occlusion of the left anterior descending coronary artery (34% vs 47%, p = 0.03) or a history of prior AMI (8% vs 16%, p = 0.02). The triple composite end point of death, reinfarction, or refractory ischemia occurred less frequently in the ionic group, both in the hospital (4.4% vs 11%, p = 0.018) and at 30 days (5.5% vs 11%, p = 0.044). Although the trend favoring ionic contrast persisted, the differences were no longer statistically significant after adjustment for imbalances in baseline characteristics using a risk model developed from the study sample (n = 454, adjusted odds ratio for ionic contrast 0.48 [0.22 to 1.02], p = 0.055), and using a model developed from the entire GUSTO IIb study cohort (n = 12,142, adjusted odds ratio for ionic contrast 0.50 [0.23 to 1.06], p = 0.072). The results of this observational study warrant further elucidation by a randomized study design in this setting.

A comparison of the efficacy and safety of ioxaglate and iobitridol in renal angioplasty

PURPOSE

To compare ioxaglate and iobitridol for percutaneous transluminal renal angioplasty (PTRA) as regards thromboembolic complications, the quality of diagnosis, and renal and general safety.

METHODS

One hundred and eighty-nine patients were prospectively studied, 98 of whom received ioxaglate, and 91, iobitridol. Twenty-two were secondarily excluded from the evaluation of thromboembolic complications as they did not undergo PTRA.

RESULTS

Two hundred and two PTRAs were performed. The total volumes of contrast medium administered and the procedure durations were the same for each patient. In the ioxaglate group, four dissections (3 stents), one occlusive dissection, and two spasms occurred; in the iobitridol group, there were three dissections (all stented), one occlusive dissection (stented), and two spasms. The final angiograms showed four renal infarctions with ioxaglate (2 of which were in patients who were not anticoagulated), two with iobitridol. No significant difference was seen in the incidence of thromboembolic complications when the PTRA was performed after anticoagulation (n = 150; 3.9% vs 4%, p = 0.78); in the whole population, thromboembolic complications were more frequent in the ioxaglate group but the difference was not significant (5.7% vs 3.7%, p = 0.74). The quality of the diagnosis and the general and renal safety were the same in the two groups.

CONCLUSION

Regarding the clotting phenomenon, we recorded as many thromboembolic complications with ioxaglate as with iobitridol.

Influence of a nonionic, iso-osmolar contrast medium (iodixanol) versus an ionic, low-osmolar contrast medium (ioxaglate) on major adverse cardiac events in patients undergoing percutaneous transluminal coronary angioplasty: A multicenter, randomized, double-blind study. Visipaque in Percutaneous Transluminal Coronary Angioplasty [VIP] Trial Investigators

BACKGROUND

The potential merits and disadvantages of the use of ionic or nonionic contrast media in patients undergoing percutaneous transluminal coronary angioplasty (PTCA) have been the subjects of controversy. The present study was designed to evaluate the possible influence of both types of contrast media on major adverse cardiac events (MACE) in patients undergoing PTCA.

METHODS AND RESULTS

In a randomized, parallel-group, double-blind study, 1411 patients received either iodixanol (a nonionic, iso-osmolar contrast medium) or ioxaglate (an ionic, low-osmolar contrast medium) during PTCA. A standardized anticoagulation regimen was followed. Patients were monitored in the hospital for 2 days and followed-up at 1 month. The primary end point, a composite of MACE (death, stroke, myocardial infarction, coronary artery bypass grafting, and re-PTCA) after 2 days, occurred in 4.3% of the total population, with no statistically significant difference between groups (iodixanol, 4.7%; ioxaglate, 3.9%; P=0.45). Further, between 2-day and 1-month follow-ups, no significant difference (P=0.27) existed between the groups in the rates of MACE. Hypersensitivity reactions (P=0.007) and adverse drug reactions (P=0.002) were significantly less frequent in the iodixanol group. The only significant predicting factors for the occurrence of MACE were dissection/abrupt closure and country.

CONCLUSIONS

No significant differences were observed between the iodixanol and ioxaglate groups with regard to MACE, although hypersensitivity and adverse drug reactions were significantly less frequent in patients who received iodixanol.

Thrombotic risk associated with the use of iodinated contrast media in interventional cardiology: pathophysiology and clinical aspects

A review of the current knowledge of the anti-thrombotic properties of iodinated contrast media (CM) has been conducted. CM are classified according to their chemical structure, either ionic or non-ionic (monomeric or dimeric). Numerous in vitro and in vivo data show that, although all CM have anti-coagulant properties, ionic molecules are more potent than non-ionic and, furthermore, do not activate resting platelets, unlike non-ionic agents. These properties may lead to a decrease in thrombus formation during interventional procedures. Several clinical trials have shown that CM may play a role in the occurrence of acute thrombotic complications but also in delayed ischaemic events during interventional procedures. A recent meta-analysis showed that, compared to non-ionic monomers, ionic low-osmolar CM reduce the rate of coronary artery abrupt closure, but no significant difference was found with respect to ischaemic complications. Ionic CM lead to a lower deposit of thrombotic materials on catheters and guide-wires. To date, clinical data comparing ionic CM and non-ionic dimers are scarce, significantly heterogeneous and, unlike experimental data, they do not show differences between both classes of CM. Further studies are required to better understand the precise mechanisms of such interactions and to analyse the effect of CM when new antiplatelet agents or new procedures (stenting) are used, to comply with new clinical strategies.

A randomized trial comparing the impact of a nonionic (Iomeprol) versus an ionic (Ioxaglate) low osmolar contrast medium on abrupt vessel closure and ischemic complications after coronary angioplasty

OBJECTIVES

To assess the effect of nonionic versus ionic contrast media on abrupt vessel closure and major ischemic complications after coronary angioplasty.

BACKGROUND

There is a continuous debate about the "thrombogenic potential" of nonionic contrast media. The results of both in vitro and in vivo investigations are incongruent.

METHODS

We prospectively evaluated the outcomes of 2,000 patients undergoing percutaneous transluminal coronary angioplasty (PTCA). According to a randomized, double-blind protocol, they received either iomeprol (nonionic; n = 1,001) or ioxaglate (ionic; n = 999). Intracoronary thrombus before PTCA was found more often in the iomeprol group (4.2% vs 2.7%, p = 0.04). No other significant differences between both groups were observed with regard to pre-PTCA clinical and angiographic characteristics.

RESULTS

The frequency of reocclusions necessitating repeat angioplasty occurring either in laboratory (2.9% with iomeprol and 3.0% with ioxaglate) or out of laboratory (3.1% vs 4.1%) was not significantly different. The rate of major ischemic complications was also comparable after both contrast media (emergency bypass surgery: 0.8% vs 0.7%, myocardial infarction: 1.8 vs 2.0%, cardiac death during hospital stay: 0.2% vs 0.2%). In the iomeprol group, more patients had dissections post-PTCA (30.2% vs 25.0%, p = 0.01) and more patients received intracoronary stents (31.6% vs 25.7%, p = 0.004). Allergic reactions requiring treatment occurred only in the ioxaglate group (0.0% vs 0.9%, p = 0.002).

CONCLUSIONS

The nonionic contrast medium was not associated with a higher rate of abrupt vessel closure requiring repeat angioplasty, or major ischemic events. These data suggest that nonionic contrast media do not increase the risk of thrombotic complications in patients undergoing coronary interventions.

Comparison of ionic and nonionic low osmolar contrast media in relation to thrombotic complications of angioplasty in patients with unstable angina

BACKGROUND

Acute complications of percutaneous transluminal coronary angioplasty (PTCA) are more common in patients with unstable coronary syndromes. The objective of this study was to prospectively determine the differences between ionic and nonionic low osmolar contrast media (LOCM) on potential risk of acute complications, particularly abrupt vessel closure, in patients with unstable angina undergoing PTCA.

METHODS

A total of 210 patients with 278 lesions were randomized to receive either ionic or nonionic LOCM during PTCA. Quantitative coronary angiographic measurements and assessment of filling defects were made by experienced observers who were blinded to the type of contrast media used.

RESULTS

The baseline clinical and angiographic characteristics, the immediate postangioplasty results, and clinical outcome were similar in both groups. Subacute recoil, defined as the difference between minimal luminal diameter (in millimeters) at 0 and 15 minutes after angioplasty, was significantly greater in patients receiving nonionic LOCM (0.17 +/- 0.36 mm vs 0.07 +/- 0.18 mm, p = 0.004). A filling defect abnormality attributable to dissection, thrombus, or a combination of the two was noted in similar proportions of the two groups. Although nonsignificant, more thrombus was noted in the nonionic group (21 of 129 vs 15 of 141, p = NS). The abrupt vessel closure rate was similar in the two groups and was only 1.9% in the first 24 hours. However, 17 (8.3%) patients had a repeat PTCA at 15 minutes (9 ionic vs 8 nonionic).

CONCLUSION

In patients with unstable angina the choice of ionic or nonionic LOCM does not appear to significantly affect the clinical outcome of PTCA.

Physicians' judgments of the risks of cardiac procedures. Differences between cardiologists and other internists

OBJECTIVES

The authors compared judgments of the population risks of invasive cardiac procedures made by cardiologists and other internal medicine physicians. Our main hypotheses were that cardiologists' judgments would differ from those made by the other physicians and that cardiologists' judgments would be more accurate than those of other physicians.

METHODS

This was a cross-sectional survey of senior staff and physician-trainees at two teaching hospitals affiliated with a US medical school, Emergency Department physicians at a community hospital in the same metropolitan area, and senior staff and trainees at two teaching hospitals affiliated with a UK school. Judgments of the risks of severe morbidity and death due to Swan-Ganz catheterization, cardiac catheterization, percutaneous coronary angioplasty, and coronary artery bypass grafting were assessed.

RESULTS

Nineteen cardiologists judged the risks of severe morbidity due to all procedures and the risks of death due to all procedures except coronary artery bypass grafting to be significantly lower than did the 78 other internists. Cardiologists more frequently made accurate judgments of the rates of morbidity and death due to cardiac catheterization than did the other internists; other internists more frequently made accurate judgments for the rates of morbidity due to Swan-Ganz catheterization.

CONCLUSIONS

Disagreements about the risks of procedures may arise from a paucity of published data, or from an over-supply of confusing data.

A randomized trial of low osmolar ionic versus nonionic contrast media in patients with myocardial infarction or unstable angina undergoing percutaneous transluminal coronary angioplasty

OBJECTIVES

The purpose of this study was to determine prospectively whether the differences in anticoagulant and antiplatelet effects of ionic and nonionic contrast media after angiographic or clinical outcomes in patients with unstable ischemic syndromes undergoing percutaneous transluminal coronary angioplasty.

BACKGROUND

The interaction of platelets and thrombin with the endothelium of injured vessels contributes to thrombosis and restenosis after coronary angioplasty. Case reports and retrospective observations have reported an increased risk of thrombosis with the use of nonionic contrast media.

METHODS

A total of 211 patients with acute myocardial infarction or unstable angina undergoing coronary angioplasty were randomized to receive nonionic or ionic low osmolar contrast media. Coronary angiograms were assessed by a technician blinded to the study contrast media, and clinical events were monitored by an independent nurse for 1 month.

RESULTS

Patients receiving the ionic media were significantly less likely to experience decreased blood flow during the procedure (8.1% vs. 17.8%, p = 0.04). After the angioplasty, residual stenosis, vessel patency, the incidence of moderate to large thrombi and use of adjunctive thrombolytic therapy were similar between the two groups. However, patients receiving ionic media had fewer recurrent ischemic events requiring repeat catheterization (3.0% vs. 11.4%, p = 0.02) and repeat angioplasty during the initial hospital stay (1.0% vs. 5.8%, p = 0.06). One month after angioplasty, patients receiving ionic contrast media reported significantly fewer symptoms of any angina (8.5 vs. 20.0%, p = 0.04) or of angina at rest (1.4% vs. 11.8%, p = 0.01) and a reduced need for subsequent bypass surgery (0% vs. 5.9%, p = 0.04), compared with patients receiving the nonionic media.

CONCLUSIONS

These findings demonstrate that in patients with unstable ischemic syndromes undergoing coronary angioplasty, the use of ionic low osmolar contrast media reduces the risk of ischemic complications acutely and at 1 month after the procedure. Therefore, low osmolar ionic contrast media should be strongly considered when performing interventions in patients with unstable angina or myocardial infarction.

Effects of an ionic versus a nonionic low osmolar contrast agent on the thrombotic complications of coronary angioplasty

An increasing body of evidence suggests that the potential for thrombotic complications is greater with nonionic than with ionic contrast agents. This is a particularly important consideration in the highly thrombogenic setting of percutaneous transluminal coronary angioplasty (PTCA). To explore this issue further, 500 consecutive patients undergoing PTCA were prospectively randomized to receive the low osmolality ionic ioxaglate or the nonionic agent iohexol. The number of acute thrombotic in-laboratory events was significantly less in the ioxaglate than in the iohexol group (8 versus 18; P < 0.05), but there was no significant difference between the 2 groups as regards the number of out-of-laboratory acute rethrombotic events. With multivariate analysis, use of the nonionic agent rather than the ionic agent emerged as an independent predictor of acute in-laboratory rethrombosis. These data suggest that, in the performance of PTCA, an ionic, rather than a nonionic, should be the preferred contrast agent.

Use of nonionic or low osmolar contrast agents in cardiovascular procedures. American College of Cardiology Cardiovascular Imaging Committee

Low osmolar contrast agents produce less adverse electrophysiologic and hemodynamic alterations during cardiac catheterization. The nonionic agents probably reduce the risk of provoking myocardial ischemia during coronary arteriography or ventriculography. Patients also report less subjective sensation of discomfort during administration of low osmolar agents for cardiovascular procedures. However, nonionic agents have not been proved to reduce the incidence of several serious complications of cardiac catheterization, including acute renal failure and anaphylactoid reaction. Although evidence is inconclusive, there may be an increased risk of thromboembolic complications during cardiac catheterization when certain low osmolar nonionic agents are administered. Nonionic contrast agents have not been definitely proved to reduce the risk of death after cardiac catheterization.

Relationship of anticoagulation and radiographic contrast agents to thrombosis during coronary angiography and angioplasty: are there real concerns?

Radiographic contrast agents are essential for the performance of coronary angiography and angioplasty. Historical data show that thrombosis-related events have occurred since coronary angiography has been performed. Newer non-ionic agents have been shown to be safer than conventional high osmolar ionic agents especially in high risk patients, but concern has been raised about a potentially increased risk of thrombosis with the use of these agents. A review of basic and clinical evidence for this perception does not support the view that an increase in thrombosis-related events has occurred as a results of non-ionic contrast media use in coronary angiographic procedures.