Society of cardiac angiography and interventions: suggested management of the no-reflow phenomenon in the cardiac catheterization laboratory

Development of Multi-Vessel Coronary No-Reflow Following Elective Percutaneous Intervention in One Vessel

Percutaneous coronary intervention (PCI) is a frequently performed procedure that can have minor or major complications. One of the more serious complications of PCI is the development of coronary no-reflow. No-reflow signifies reduced or absent coronary flow in the distal coronary circulation in the absence of flow-limiting lesions. We present a case of a middle-aged man who presented as an outpatient for elective coronary angiography due to angina pectoris and a high-risk exercise stress test. Coronary angiography demonstrated significant single-vessel disease with lesions in the proximal and mid-segments of the left anterior descending (LAD) coronary artery. Successful placement of drug-eluting stents in the LAD was followed by a severe drop in blood pressure, worsening chest pain, and ST elevation on telemetry. Immediate angiography showed the development of no-reflow in both the LAD and left circumflex coronary arteries. Ionotropic and intravenous anti-platelet agents were administered with simultaneous placement of an intra-aortic balloon pump, restoring normal flow in both arteries. No-reflow occurs most commonly following PCI in certain lesion subsets, and it is usually seen only in the vessel in which the PCI was performed (culprit vessel). It is important to realize that this phenomenon can occur in other circumstances since immediate recognition and treatment can be lifesaving.

Percutaneous coronary intervention of totally occluded coronary venous bypass grafts: An exercise in futility?

BACKGROUND

Percutaneous coronary intervention (PCI) of diseased saphenous vein grafts (SVG) continues to pose a clinical challenge. Current PCI guidelines give a class III recommendation against performing PCI on chronically occluded SVG. However, contemporary outcomes after SVG intervention have incrementally improved with distal protection devices, intracoronary vasodilators, drug-eluting stents, and prolonged dual antiplatelet therapy.

AIM

To reassess the procedural and long-term outcomes of PCI for totally occluded SVG with contemporary techniques.

METHODS

This was a retrospective observational study conducted at a single university hospital. The study population consisted of 35 consecutive patients undergoing PCI of totally occluded SVG. Post-procedure dual antiplatelet therapy was continued for a minimum of one year and aspirin was continued indefinitely. Clinical outcomes were assessed at a mean follow-up of 1221 ± 1038 d. The primary outcome was freedom from a major adverse cardiac event (MACE) defined as the occurrence of any of the following: death, myocardial infarction, stroke, repeat bypass surgery, repeat PCI, or graft reocclusion.

RESULTS

The study group included 29 men and 6 women with a mean age of 69 ± 12 years. Diabetes was present in 14 (40%) patients. All patients had Canadian Heart Classification class III or IV angina. Clinical presentation was an acute coronary syndrome in 34 (97%) patients. Mean SVG age was 12 ± 5 years. Estimated duration of occlusion was acute (< 24 h) in 34% of patients, subacute (> 24 h to 30 d) in 26%, and late (> 30 d) in 40%. PCI was initially successful in 29/35 SVG occlusions (83%). Total stent length was 52 ± 35 mm. Intraprocedural complications of distal embolization or no-reflow occurred in 6 (17%) patients. During longer term follow-up, MACE-free survival was only 30% at 3 years and 17% at 5 years.

CONCLUSION

PCI of totally occluded SVG can be performed with a high procedural success rate. However, its clinical utility remains limited by poor follow-up outcomes.

Management of Percutaneous Coronary Intervention Complications: Algorithms From the 2018 and 2019 Seattle Percutaneous Coronary Intervention Complications Conference

Complications of percutaneous coronary intervention (PCI) may have significant impact on patient survival and healthcare costs. PCI procedural complexity and patient risk are increasing, and operators must be prepared to recognize and treat complications, such as perforations, dissections, hemodynamic collapse, no-reflow, and entrapped equipment. Unfortunately, few resources exist to train operators in PCI complication management. Uncertainty regarding complication management could contribute to the undertreatment of patients with high-complexity coronary disease. We, therefore, coordinated the Learning From Complications: How to Be a Better Interventionalist courses to disseminate the collective experience of high-volume PCI operators with extensive experience in chronic total occlusion and high-risk PCI. From these conferences in 2018 and 2019, we developed algorithms that emphasize early recognition, effective treatment, and team-based care of PCI complications. We think that an algorithmic approach will result in a logical and systematic response to life-threatening complications. This construct may be useful for operators who plan to perform complex PCI procedures.

Intracoronary Nicorandil and the Prevention of the No-Reflow Phenomenon During Primary Percutaneous Coronary Intervention in Patients with Acute ST-Segment Elevation Myocardial Infarction

Background

This study aimed to investigate intracoronary nicorandil treatment on the no-reflow phenomenon (NRP) during primary percutaneous coronary intervention (PCI) in patients with acute ST-segment elevation myocardial infarction (STEMI) and to compare nicorandil with sodium nitroprusside.

Material/Methods

Patients with sustained acute STEMI who underwent primary PCI (N=120) were randomly assigned to three groups: the nicorandil-treated group (N=40) had 2 mg of nicorandil injected into the coronary artery at 2 mm beyond the occlusion with balloon pre-dilation; the sodium nitroprusside-treated group (N=40) underwent the same procedure, but with 200 μg of sodium nitroprusside; the control group (N=40) received PCI and balloon pre-dilation only. Coronary angiography, incidence of NRP, hypotensive episodes, ST-segment resolution (STR) rate, levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), creatine kinase-MB (CK-MB), cardiac troponin I (cTnI), wall motion score index (WMSI), and left ventricular ejection fraction (LVEF) were measured before and after primary PCI. Major adverse cardiovascular events (MACEs) post-PCI and at three-month follow-up were recorded.

Results

Patients in the sodium nitroprusside and nicorandil groups had significantly improved thrombolysis in myocardial infarction (TIMI) scores, TIMI myocardial perfusion grade (TMPG), and ST-segment elevation resolution (STR) (P<0.05), and a significantly lower incidence of NRP (P=0.013). The incidence of intraoperative hypotension in the sodium nitroprusside group was significantly greater than the nicorandil and control groups (P=0.035).

Conclusions

Patients with sustained acute STEMI undergoing primary PCI, treated with intracoronary nicorandil had a reduced incidence of the NRP, improved myocardial perfusion and cardiac function.

Coronary artery ectasia - A sample from Saudi Arabia

INTRODUCTION

Coronary artery ectasia is an uncommon disease that has been increasingly noticed as the increase in utilization of coronary angiograms. The aim of this study is to characterize coronary artery ectasia in the population of Saudi Arabia.

METHODS

This is a retrospective study involved all patient with invasive coronary angiogram that was done at a tertiary hospital in Saudi Arabia from January 2011 to December 2013.

RESULTS

A total of 1115 coronary angiograms were reviewed. Coronary artery ectasia was found in 67 patients (6% of all coronary angiograms). The right coronary artery was involved in 73% of cases. And 43% of the cases had severe ectasia.

CONCLUSION

The prevalence of coronary artery ectasia in Saudi Arabia among patient who went for coronary angiography is higher than what has been published in previous studies and a significant number of patients have severe disease.

Acute Profound Thrombocytopenia after Using Abciximab for No-Reflow during Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction

Glycoprotein IIb/IIIa antagonists are well established for their effectiveness in improving clinical outcomes in acute coronary syndrome patients undergoing percutaneous coronary intervention. Acute profound thrombocytopenia is a rare complication of abciximab. We present a case which was managed successfully for the rare complication of acute profound thrombocytopenia after using abciximab and an intra-aortic balloon pump for the treatment of a no-reflow phenomenon and consecutive cardiogenic shock during primary percutaneous coronary intervention.

Thrombus extraction catheters vs. angiojet rheolytic thrombectomy in thrombotic lesions/SV grafts

Primary percutaneous coronary intervention, (pPCI), of native coronaries and saphenous vein grafts (SVGs), is the recommended reperfusion strategy for STEMI, and an early invasive approach is recommended for high risk patients with UA/NSTEMI. Although PCI effectively restores flow in the infarct related artery/culprit vessel in both situations, myocardial perfusion often remains suboptimal due to microvascular obstruction, partly attributed to distal embolization of thrombus. Hence, thrombectomy (manual or mechanical), prior to stenting may further reduce hard clinical end points in patients with ACS. This article discusses accumulated evidence regarding the safety and effectiveness of thrombectomy in culprit native coronaries and SVGs in such patients, as well as possible strategies for maximizing its benefits relative to the size of the thrombotic burden.

Complications of coronary intervention: device embolisation, no-reflow, air embolism

The introduction of drug-eluting stents, better equipment, stronger antiplatelet drugs, and higher levels of operator experience has led to markedly improved patency rates for complex percutaneous coronary interventions (PCIs). The evolving techniques of contemporary PCI have been unable to completely eliminate complications. However, rigorous preventive measures pre-empt the appearance of complications. During traversal of severely diseased coronary arteries and manipulating equipment, particularly devices with detachable components, the opportunity for loss or embolisation of material in the coronary circulation presents itself. Device embolisation is associated with periprocedural myocardial infarction and emergent referral to surgery, particularly if the device is not retrieved. The coronary no-reflow phenomenon is a feared complication of PCI. It is associated with a worse prognosis and has been shown to be an independent predictor of death, myocardial infarction and impaired left ventricular function. Air embolism can be prevented by flushing of catheters during equipment exchanges.

Secretome of apoptotic peripheral blood cells (APOSEC) attenuates microvascular obstruction in a porcine closed chest reperfused acute myocardial infarction model: role of platelet aggregation and vasodilation

Although epicardial blood flow can be restored by an early intervention in most cases, a lack of adequate reperfusion at the microvascular level is often a limiting prognostic factor of acute myocardial infarction (AMI). Our group has recently found that paracrine factors secreted from apoptotic peripheral blood mononuclear cells (APOSEC) attenuate the extent of myocardial injury. The aim of this study was to determine the influence of APOSEC on microvascular obstruction (MVO) in a porcine AMI model. A single dose of APOSEC was intravenously injected in a closed chest reperfused infarction model. MVO was determined by magnetic resonance imaging and cardiac catheterization. Role of platelet function and vasodilation were monitored by means of ELISA, flow cytometry, aggregometry, western blot and myographic experiments in vitro and in vivo. Treatment of AMI with APOSEC resulted in a significant reduction of MVO. Platelet activation markers were reduced in plasma samples obtained during AMI, suggesting an anti-aggregatory capacity of APOSEC. This finding was confirmed by in vitro tests showing that activation and aggregation of both porcine and human platelets were significantly impaired by co-incubation with APOSEC, paralleled by vasodilator-stimulated phosphoprotein (VASP)-mediated inhibition of platelets. In addition, APOSEC evidenced a significant vasodilatory capacity on coronary arteries via p-eNOS and iNOS activation. Our data give first evidence that APOSEC reduces the extent of MVO during AMI, and suggest that modulation of platelet activation and vasodilation in the initial phase after myocardial infarction contributes to the improved long-term outcome in APOSEC treated animals.

Management of the no-reflow phenomenon

The lack of reperfusion of myocardium after prolonged ischaemia that may occur despite opening of the infarct-related artery is termed "no reflow". No reflow or slow flow occurs in 3-4% of all percutaneous coronary interventions, and is most common after emergency revascularization for acute myocardial infarction. In this setting no reflow is reported to occur in 30% to 40% of interventions when defined by myocardial perfusion techniques such as myocardial contrast echocardiography. No reflow is clinically important as it is independently associated with increased occurrence of malignant arrhythmias, cardiac failure, as well as in-hospital and long-term mortality. Previously the no-reflow phenomenon has been difficult to treat effectively, but recent advances in the understanding of the pathophysiology of no reflow have led to several novel treatment strategies. These include prophylactic use of vasodilator therapies, mechanical devices, ischaemic postconditioning and potent platelet inhibitors. As no reflow is a multifactorial process, a combination of these treatments is more likely to be effective than any of these alone. In this review we discuss the pathophysiology of no reflow and present the numerous recent advances in therapy for this important clinical problem.

New method of intracoronary adenosine injection to prevent microvascular reperfusion injury in patients with acute myocardial infarction undergoing percutaneous coronary intervention

The aim of our study was to examine the role of a new, simple protocol of intracoronary adenosine administration performed during primary angioplasty on the immediate angiographic results and clinical course. A prospective, single-center, randomized, placebo-controlled trial of 70 consecutive patients (64 ± 14 years, 54 men) with acute myocardial infarction with ST-segment elevation undergoing primary percutaneous coronary intervention (PCI) was conducted. Patients were randomized to 2 groups. Group 1 (n = 35) received intracoronary adenosine (1 to 2 mg) with a hand injection through the guiding catheter 2 times: immediately after crossing the lesion of the infarct-related artery with guidewire and then after the first balloon inflation. Group 2 (n = 35) received placebo. The baseline clinical and angiographic characteristics of the 2 groups were similar. Percutaneous coronary intervention resulted in Thrombolysis In Myocardial Infarction grade 3 flow after PCI in 32 patients (91.4%) in the adenosine group and 27 patients (77.1%) in the placebo group (p = 0.059). Myocardial blush grade 3 was observed at the end of PCI in 23 patients (65.7%) in the adenosine group and 13 (37.1%) in the placebo group (p < 0.05). Resolution of ST-segment elevation (> 50%) was more frequently observed in the adenosine than in the placebo group: 27 (77%) versus 15 (43%), respectively (p < 0.01). In conclusion, intracoronary adenosine administration improved the angiographic and electrocardiographic results in patients with acute myocardial infarction with ST-segment elevation undergoing PCI. Adenosine administration seemed to be associated with a more favorable clinical course.

Emerging drugs for acute myocardial infarction

IMPORTANCE OF THE FIELD

The present review is aimed at going over the pharmacological profile (and the clinical impact) of the emerging drugs involved in the management of patients with ST-elevation myocardial infarction (STEMI) in order to provide the cardiologists who deal with these patients in the early phase with the most recent evidence on this topic.

AREAS COVERED IN THIS REVIEW

Anticoagulant and antiplatelet drugs are the main cornerstones of therapy in the treatment of STEMI patients undergoing primary percutaneous coronary intervention (PCI). The main issues that clinicians have to deal with are represented by balancing thrombotic and bleeding risks. In tailoring therapy, variables such as age, sex and previous disease should be taken into account, as well as ongoing complications (such as acute renal failure) that could affect hemostasis. Despite the well-established clinical benefits of antiplatelet agents, questions remain, mainly surrounding potential for variable platelet response, which are strictly related to non-genetic (i.e., diet, drug-drug interaction, clinical factors such as obesity, diabetes mellitus, and inflammation) and genetic determinants.

WHAT THE READER WILL GAIN

In their daily practice, cardiologists cannot abstract from the knowledge and updating on the ongoing research fields as well as the newly developed drugs, which they should frame in the very patient in the attempt to the develop a personalized medical strategy. These include also the pharmacological option(s) in the treatment of the reperfusion injury, the metabolic aspects and the stem cell therapy. TAKE HOME MASSAGE: In our opinion, the goal of ongoing research on the pharmacological approach to STEMI patients is a personalized medical strategy that relies on critical clinicians who merge newly developed acquisitions on this topic and a more complete, systemic and critical approach to the patient.

The pathogenesis and treatment of no-reflow occurring during percutaneous coronary intervention

No-reflow is one of the major causes of postinterventional rise of cardiac enzyme and myocardial infarction (MI). This complication is associated with substantial morbidity and mortality after percutaneous coronary intervention (PCI). During and after a no-reflow episode, the patient can suffer from severe chest pain, hypotension, bradycardia, hemodynamic collapse, MI, congestive heart failure, and death. Every effort should be taken to reduce the incidence of this complication. The distal embolic protection device has been shown to decrease this risk in saphenous vein graft (SVG) interventions but not in native coronaries. On the other hand, the use of glycoprotein IIb/IIIa receptor antagonists have been effective in reducing the occurrence of no-reflow during PCI of native coronaries but not during SVG interventions. The treatment of no-reflow is based on the intracoronary administrations of medications that induce maximal vasodilatation in small distal coronary vasculature. The most commonly used drugs in this setting are adenosine, nitroprusside, and verapamil. The goal of this study was to review the pathogenesis and treatment of no-reflow in patients undergoing PCI.

Management of 'no-reflow' complicating reperfusion therapy

No-reflow phenomenon, defined as inadequate myocardial perfusion of the adequately dilated target vessel without evidence of angiographic mechanical obstruction. It is a multifactorial, well-recognised, secondary phenomenon following reperfusion therapy such as thrombolysis or percutaneous coronary interventions (PCI). The pathophysiological mechanisms leading to the no-reflow state are incompletely understood. Embolization of the atheromatous material to the distal vasculature and intense arteriole vasospasm caused by microembolization of platelet-rich thrombi that release vasoactive agents resulting in microvascular obstructions are likely mechanisms. Current prophylaxis and management strategies are derived from limited clinical data. Intracoronary verapamil, adenosine and nitroprusside have been most frequently studied and administered for angiographic no-reflow during PCI for acute myocardial infarction or saphenous vein graft (SVG) lesions and have been shown to improve epicardial flow and microvascular perfusion. The use of distal embolic protection devices in SVG interventions also provide microvascular protection and improve clinical outcomes. However, by far the most important measures are prevention and anticipation during PCI as once no-reflow established, complete reversal of the situation may not be possible.

Intracoronary Vasodilators for the No-Reflow Phenomenon

Objective:

To review the literature relating to the use of intracoronary vasodilators to prevent and/or treat the no-reflow phenomenon in patients undergoing percutaneous coronary intervention (PCI).

Data Sources:

A literature search was conducted using MEDLINE (1966–March 2008) and Science Citation Index (1945–March 2008) using the search terms vasodilators, no-reflow, and intracoronary.

Study Selection and Data Extraction:

English-language clinical trials and case series were selected from articles retrieved. References of reviewed articles were examined for additional sources. Studies relating to the use of intracoronary vasodilators in the prevention and/or treatment of no-reflow in PCI were evaluated for safety and efficacy data. Articles relating to agents not available in the US were excluded.

Data Synthesis:

Evidence of intracoronary adenosine's utility in no-reflow treatment is limited. Its use in no-reflow prevention was associated with outcomes ranging from no difference to nearly an 88% reduction in no-reflow development; the drug was generally well tolerated. No-reflow treatment with intracoronary verapamil improved flow in 87–100% of cases. Preventive trials with verapamil failed to demonstrate efficacy. Atrioventricular block requiring treatment was the most commonly reported adverse event with intracoronary verapamil. Literature on intracoronary diltiazem and intracoronary nicardipine is limited. Both agents produced greater than 95% efficacy in no-reflow treatment, while prevention studies found no-reflow developing in less than 4% of patients. Although adverse event reporting was limited, hemodynamic instability was noted in patients receiving diltiazem. Response rates ranged from 73% to 100% when intracoronary nitroprusside was studied as treatment for no-reflow associated with acute myocardial infarction (AMI). Systemic hypotension was noted with nitroprusside administration.

Conclusions:

The available data are predominately from case series and retrospective reviews. Prevention of no-reflow with intracoronary vasodilators in elective PCI is not warranted. Nitroprusside should be considered first-line treatment in no-reflow associated with AMI.

Efficacy of intracoronary nicardipine in the treatment of no-reflow during percutaneous coronary intervention

OBJECTIVES

The goal of this study was to evaluate the safety and efficacy of nicardipine in reversing no-reflow during percutaneous coronary intervention (PCI).

BACKGROUND

No-reflow is a common complication of PCI in patients with acute coronary syndromes or venous bypass graft disease. Although nicardipine has an attractive pharmacological profile and has been used clinically to treat no-reflow, there is a paucity of published data regarding its effectiveness in this setting.

METHODS

We conducted a retrospective analysis of 72 consecutive patients who received intracoronary nicardipine to reverse no-reflow during coronary intervention. Qualitative TIMI flow grade and quantitative TIMI frame count methods were used to assess the efficacy of nicardipine.

RESULTS

A mean of 460 +/- 360 mcg of intracoronary nicardipine was used. No-reflow was successfully reversed with complete restoration of TIMI 3 flow in 71 of 72 patients (98.6%). TIMI flow grade improved from 1.65 +/- 0.53 prior to nicardipine to 2.97 +/- 0.24 after treatment (P < 0.001). TIMI frame count decreased from 57 +/- 40 at the time of no-reflow to 15 +/- 12 after nicardipine administration (P < 0.001). Nicardipine therapy was well tolerated without adverse hemodynamic or chronotropic effects.

CONCLUSIONS

In this largest series to date, intracoronary nicardipine was demonstrated to be a safe and highly effective pharmacological agent to reverse no-reflow during PCI.

Assessment of intermediate severity coronary lesions in the catheterization laboratory

The management of intermediate coronary lesions, defined by a diameter stenosis of 40% to 70%, continues to be a therapeutic dilemma for cardiologists. The 2-dimensional representation of the arterial lesion provided by angiography is limited in distinguishing intermediate lesions that require stenting from those that simply need appropriate medical therapy. In the era of drug-eluting stents, some might propose that stenting all intermediate coronary lesions is an appropriate solution. However, the possibility of procedural complications such as coronary dissection, no reflow phenomenon, in-stent restenosis, and stent thrombosis requires accurate stratification of patients with intermediate coronary lesions to appropriate therapy. Intravascular ultrasound (IVUS) and fractional flow reserve index (FFR) provide anatomic and functional information that can be used in the catheterization laboratory to designate patients to the most appropriate therapy. The purpose of this review is to discuss the critical information obtained from IVUS and FFR in guiding treatment of patients with intermediate coronary lesions. In addition, the importance of IVUS and FFR in the management of patients with serial stenosis, bifurcation lesions, left main disease, saphenous vein graft disease, and acute coronary syndrome will be discussed.

Imaging microvascular obstruction and its clinical significance following acute myocardial infarction

Obstruction of the coronary microvasculature contributes to the pathophysiology of MI and adversely affects post-MI recovery. This "no-reflow" phenomenon resulting from microvascular obstruction is an indicator of lack of adequate tissue perfusion within the infarcted myocardium, even after restoration of epicardial blood flow. Regions of microvascular obstruction can be detected and quantifed because of rapid advances in and refinement of imaging technologies over the past decade. This article focuses on the non-invasive imaging modalities used to assess MO, discusses the prognostic implications of MO, and briefly addresses strategies for reducing MO.

Coronary Arterial Plaque Characterized by Multislice Computed Tomography Predicts Complications Following Coronary Intervention

BACKGROUND

A reliable, noninvasive assessment of plaque configuration would constitute an important step forward for predicting complications following percutaneous coronary intervention (PCI). Multislice computed tomography (MSCT) holds promise with respect to allowing for differentiation of coronary lesion configuration. However, it has not yet been clarified whether the characteristics of coronary artery plaque measured by MSCT predict complications after PCI. The aim of this study was to investigate the relationship between plaque configuration and complications after coronary intervention in patients with stable angina pectoris.

METHODS

MSCT was performed in patients with angina pectoris who were scheduled for PCI prospectively, and 26 patients (70 +/- 11 years, 18 males) with coronary artery plaque in a stenotic coronary artery measured by MSCT were recruited for this study. Thirty-five plaques in the stenotic coronary lesions were divided into 3 groups based on the CT density as soft, intermediate, and hard, and were compared with the complications after PCI.

RESULTS

The soft plaque group before PCI (n = 11) was significantly associated with the appearance of slow flow (n = 4) or a compromised side branch (n = 1) after PCI, whereas the hard plaque group before PCI (n = 17) was associated with the appearance of dissection (n = 2) or perforation (n = 1) after PCI (P = 0.004). The intermediate plaque group (n = 7) had only one complication, a compromised side branch (n = 1).

CONCLUSION

Coronary arterial plaque characterized by MSCT can predict intervention-related complication. It may be important for the risk stratification of the patients scheduled to undergo PCI to investigate plaque configuration by MSCT.

Comparison of coronary arterial finding by intravascular ultrasound in patients with "transient no-reflow" versus "reflow" during percutaneous coronary intervention in acute coronary syndrome

Previous studies have shown that transient no-reflow during coronary intervention but with Thrombosis in Myocardial Infarction (TIMI) grade 3 flow at the completion of the procedure is associated with increased in-hospital and 6-month mortality. We hypothesized that the use of intravascular ultrasound before intervention could identify morphologic features that were predictive of transient no-reflow in patients who had acute coronary syndrome (ACS). We analyzed 220 patients with ACS who had suitable intravascular ultrasound images that were acquired before intervention. We defined "transient no-reflow" as TIMI grade 0, 1, or 2 flow during the procedure and TIMI grade 3 flow at the completion of the procedure. We defined "reflow" as good coronary flow (TIMI grade 3 flow) during and after the procedure. Patients were categorized to a transient no-reflow group (n = 20) or a reflow group (n = 200). In the transient no-reflow group, vessel area and amount of plaque burden in the culprit lesion were significantly greater than in the reflow group (vessel 20.8 +/- 5.4 vs 16.4 +/- 6.2 mm(2), p < 0.01; plaque burden 0.90 +/- 0.03 vs 0.83 +/- 0.08, p < 0.001). The presence of ruptured plaque, lipid pool-like images, and thrombus formation were significantly higher in the transient no-reflow group than in the reflow group. Multivariate analysis identified the presence of thrombus formation (odds ratio 4.53, 95% confidence interval 1.03 to 20.0, p = 0.04) and larger plaque burden (odds ratio 1.79, 95% confidence interval 1.01 to 3.23, p = 0.05) as independent predictors of transient no-reflow. In conclusion, lesion morphologies are different for transient no-reflow and reflow. These findings suggest that the presence of thrombus formation and large plaque burden increase the risk for developing transient no-reflow during coronary intervention for ACS.

Large tube section is the key to successful coronary thrombus aspiration: Findings of a standardized bench test

Thrombus removal by aspiration is one of the adjunctive techniques used to avoid embolization during PCI for acute myocardial infarction. Numerous devices are now available, but little is known about the mechanical rationale used in comparing them. The aim of the present study was to determine parameters to obtain optimal thrombus aspiration (TA). Heparin- and antiplatelet-free blood samples were aspirated into 3 mm diameter standardized glass tubes to create a 30 mm long thrombus. Thrombus formation took place at room temperature over a period of 6 or 12 hr. Various catheters were tested using a variable vacuum device: three with right-angle distal tip (0.038'', 0.067'', and 0.070'') and one with a beveled distal (length of the beveled, 0.054''; inner diameter catheter, 0.040''). The single endpoint was complete thrombus aspiration. A total of 103 TAs were presented for the four catheters. For 6- or 12-hr-old thrombus for a given catheter, there was no significant difference in vacuum pressure required to succeed TA (P = 0.47). For 6- or 12-hr-old thrombus, the larger the contact area is, the lower the pressure needed to aspirate the thrombus. Moreover, a beveled distal tip length (0.054'') does not make it possible to succeed TA at a lower pressure. The main factor for successful TA for thrombi > or = 6 hr is inner diameter and not immediate thrombus contact area.

Peri-procedural myocardial injury: 2005 update

During the past three decades, percutaneous coronary intervention has become one of the cardinal treatment strategies for stenotic coronary artery disease. Technical advances, including the introduction of new devices such as stents, have expanded the interventional capabilities of balloon angioplasty. At the same time, there has been a decline in the rate of major adverse cardiac events, including Q-wave acute myocardial infarction, emergency coronary artery bypass grafting, and cardiac death. Despite these advances, the incidence of post-procedural cardiac marker elevation has not substantially decreased since the first serial assessment 20 years ago. As of now, these post-procedural cardiac marker elevations are considered to represent peri-procedural myocardial injury (PMI) with worse long-term outcome potential. Recent progress has been made for the identification of two main PMI patterns, one near the intervention site (proximal type, PMI type I) and one in the distal perfusion territory of the treated coronary artery (distal type, PMI type II) as well as for preventive strategies. Integrating these new developments into the wealth of clinical information on this topic, this review aims at giving a current perspective on the entity of PMI.

Impact of Reversibility of No Reflow Phenomenon on 30-Day Mortality Following Percutaneous Revascularization for Acute Myocardial Infarction-Insights from a 1,328 Patient Registry

BACKGROUND

Occurrence of no reflow phenomenon during percutaneous coronary intervention (PCI) is associated with increased mortality. Although intracoronary medications can improve coronary flow, the effect on mortality is not known.

METHODS

Patients who had PCI for myocardial infarction (MI) at the Singapore National University Hospital from January 2000 to March 2004 were studied. Our analysis stratified patients into three groups according to the occurrence and persistence of no reflow during PCI. (1) Adequate reflow: without no reflow occurrence; (2) Reversible no reflow: no reflow occurred, but final thrombolysis in myocardial infarction (TIMI) 3 flow restored after intracoronary medications; and (3) Refractory no reflow: no reflow occurred and persisted, final TIMI flow < 3 despite medications. Thirty-day mortality was determined for each group.

RESULTS

A total of 1,328 patients (82% male), 703 (53%) underwent primary PCI and 625 (47%) rescue PCI were analyzed. Among the study patients, no reflow (including reversible and refractory) occurred in 135 patients (10.2%). Intracoronary verapamil, adenosine, nitroprusside, or a combination of drugs were used to treat the no reflow in 70.0%, 17.7%, 3.5%, and 8.8% of cases, respectively. Intracoronary medications successfully restored final TIMI 3 in 108 patients (80%, reversible no reflow). The remaining 27 patients (20%) have final TIMI < 3 (refractory no reflow). In comparison with the adequate reflow and reversible no reflow groups, those with refractory no reflow had an increased 30-day mortality (3.7% vs 2.8% vs 32.0%, P < 0.001). Logistic regression analyses showed that patients with refractory no reflow had a significantly higher 30-day mortality compared to patients with adequate reflow (P < 0.001) and reversible no reflow (P = 0.001), but no significant differences in the 30-day mortality between patients with adequate reflow and reversible no reflow (P = 0.157) were detected after adjusting for relevant covariates.

CONCLUSION

Among patients undergoing PCI for MI, reversible no reflow was associated with a significantly lower 30-day mortality compared with the refractory counterpart.

Initial thrombosuction with subsequent angioplasty in primary coronary intervention—comparison with conventional strategy

BACKGROUND

Large thrombus burden remains challenging in the setting of acute myocardial infarct. Initial thrombosuction (IT) followed by actual angioplasty may be advantageous over conventional strategy in primary percutaneous coronary intervention (PCI).

METHODS

With a case-control design, 22 consecutive patients receiving primary PCI with IT were designated as group 1. Another 22 well-matched patients undergoing primary PCI with conventional strategy in the same period were enrolled as group 2. Clinical and angiographic outcomes, procedural parameters and resource usage were compared.

RESULTS

Baseline characteristics were comparable, including the symptom onset-to-needle time (250+/-101 vs. 261+/-149 min, p = NS). Total procedure time (33+/-14 vs. 47+/-20 min, p = 0.011), fluoroscopy time (10+/-6 vs. 16+/-10 min, p = 0.014) and contrast medium consumption (140+/-40 vs. 170+/-50 ml, p = 0.024) were all significantly reduced with group 1. No-reflow occurred less frequently with group 1 (5% vs. 32%, p = 0.046) during intervention, and TIMI 3 flow was established more quickly (19+/-10 vs. 30+/-20 min, p = 0.024). Final TIMI 3 flow rates and stent rates were similar. The time to myocardial enzyme peak was shorter with group 1 (9.7+/-3.1 vs. 12.8+/-6.3 h, p = 0.048), but no difference was found in 3 months cumulative major cardiac adverse event rates.

CONCLUSIONS

Primary PCI with IT achieves earlier reperfusion and is more efficient in terms of time and resource, comparing to conventional strategy.

Treatment of slow/no-reflow phenomenon with intracoronary nitroprusside injection in primary coronary intervention for acute myocardial infarction

Slow/no-reflow phenomenon is a serious problem complicating primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) and is associated with a poor prognosis. From January 2002 to November 2002, 11 of the 70 consecutive patients with ST elevation AMI who were subjected to primary PCI using balloon angioplasty and/or stenting developed slow/no-reflow phenomenon (TIMI 1 flow in 2, TIMI 2 in 8, and TIMI 2.5 in 1). They were 10 men and 1 woman, aged 64 +/- 11 years (range, 46-81). The culprit vessels were six in the left anterior descending coronary artery, three in the right coronary artery, one in the left circumflex coronary artery, and one in saphenous vein graft. Multiple bolus doses (100 microg) of nitroprusside were injected into the index artery through the guiding catheter using a 3 ml syringe until the TIMI flow grade improved by at least one grade or the systolic pressure decline below 80 mm Hg (one patient). The total drug dose varied from 100 to 700 microg. Following the drug treatment, angiographic TIMI flow grade improved by at least one grade in 9 (82%) of the 11 patients (P = 0.007). The TIMI frame counts significantly decreased from 36 +/- 17 frame counts to 16 +/- 11 frame counts (P = 0.012). All patients were discharged without major adverse cardiovascular events. Intracoronary bolus injection of nitroprusside using a 3 ml syringe appears to be a feasible, safe, and effective technique for the management of slow/no-reflow phenomenon complicating primary PCI.

Incidence and Management of "No-Reflow" Following Percutaneous Coronary Interventions

No-reflow is a complex condition associated with inadequate myocardial perfusion of the coronary artery in the absence of epicardial obstruction. It can occur in several settings, including percutaneous coronary intervention, especially in complex thrombotic lesions of native arteries and vein grafts and in primary angioplasty. The causes of no-reflow are not completely understood, and current treatments consist of intracoronary vasodilators, antithrombotic therapies, and mechanical devices (including aspiration thrombectomy catheters and embolic protection devices).

Coronary Blood Flow Assessment After Successful Angioplasty for Acute Myocardial Infarction Predicts the Risk of Long-Term Cardiac Events

Background— Analysis of coronary flow velocity (CFV) in the recanalized infarct-related coronary artery (IRA) with a Doppler guidewire is useful for predicting recovery of regional left ventricular function, in-hospital complications, and survival. We postulated that the CFV pattern after IRA reperfusion for acute myocardial infarction (AMI) would predict long-term adverse cardiac events.

Methods and Results— Sixty-eight consecutive patients with a first AMI underwent CFV measurement with a Doppler guidewire after successful reopening of the IRA by coronary angioplasty. At the end of follow-up, 3.8±1.7 years after AMI, 44 of the 65 surviving patients (67.7%) were free of long-term cardiac events. Univariate analysis showed that the following factors were predictive of an end point combining cardiac death, recurrent MI, and congestive heart failure: hypertension, age ≥65 years, time from onset of chest pain to PTCA ≥6 hours, peak creatine kinase >4000 IU/L, ejection fraction ≤50%, proximal left anterior descending artery occlusion, resting average peak velocity ≤10 cm/s, average systolic peak velocity ≤5 cm/s, a rapid diastolic deceleration time (≤600 ms), and early retrograde systolic flow. In the final multivariate model, only age ≥65 years (OR, 3.6; 95% CI, 1.1 to 11.8; P =0.03), time to PTCA ≥6 hours (OR, 2.9; 95% CI, 1.0 to 8.3; P =0.04), and a rapid diastolic deceleration time (OR, 5.4; 95% CI, 1.5 to 19.3; P =0.01) were independent predictors.

Conclusions— The CFV pattern appears to be an accurate predictor of long-term cardiac events in patients having undergone successful reopening of the IRA after AMI, identifying a subset of at-risk patients.

The no-reflow phenomenon in coronary arteries

No reflow occurs when there is inadequate myocardial perfusion of a given segment of the coronary circulation without evidence of epicardial vessel obstruction. It is a rare but clinically significant condition associated with myocardial infarction and coronary interventions. Diagnosis is usually based on clinical signs of myocardial ischemia (symptoms and/or ECG changes) combined with coronary angiography. Management can be difficult and primarily consists of intracoronary administration of vasodilators. One interesting etiology is thromboembolism and this has become the focus for new potential treatments, including distal embolic protection devices.