Using extracorporeal membrane oxygenation to rescue acute myocardial infarction with cardiopulmonary collapse: The impact of early coronary revascularization

Objectives

To investigate the therapeutic impact of combining extracorporeal membrane oxygenation (ECMO) and early coronary revascularization on acute myocardial infarction (AMI)-induced cardiopulmonary collapse.

Materials and methods

This retrospective study included 35 consecutive patients rescued by ECMO for AMI-induced cardiopulmonary collapse in a single institution between June 2003 and December 2011. Coronary revascularization was performed soon after ECMO initiation. Percutaneous coronary intervention (PCI) was the primary revascularization strategy. Coronary artery bypass grafting (CABG) was performed if an unsuitable anatomy or unsatisfactory result of PCI. Comparisons were performed in groups with different revascularization strategies and outcomes.

Results

Among the 35 patients, 16 underwent CABG and 1 was bridged to transplant after CABG. Compared to patients receiving PCI only, the CABG group showed similar results in ECMO weaning (58% vs. 69%, p = 0.51), hospital discharge (32% vs. 50%, p = 0.27), and left ventricular ejection fraction before discharge (45% vs. 49%, p = 0.92). Regardless of revascularization strategies, this protocol achieved an ECMO-weaning rate of 63% and a hospital discharge rate of 40%. Dialysis-dependent acute renal failure (OR 5.4, 95% CI: 1.1–27.5) and profound anoxic encephalopathy (OR 5.4, 95% CI: 1.1–27.5) predicted non-weaning of ECMO. Age > 60 years (OR 7.3, 95% CI: 1.1–51.0) and profound anoxic encephalopathy (OR 24.6, 95% CI: 2.3–263.0) predicted in-hospital mortality. The major cardiovascular adverse effect (MACE)–free survival was 77% in the first year after discharge.

Conclusion

Early revascularization on ECMO is practical to preserve myocardial viability and bridge patients collapsing with AMI to recovery.     

A Case of Spontaneous Coronary Artery Dissection: It is Not Always Plaque Rupture

Background

Spontaneous coronary artery dissection (SCAD) is an extremely rare cause of acute coronary syndrome (ACS). Patients may present with a broad spectrum of clinical scenarios, ranging from angina pectoris to myocardial infarction, cardiogenic shock, and sudden death. Standard therapy has not been established; current treatments range from conservative management to percutaneous revascularization or coronary artery bypass surgery.

Objective

SCAD greatly mimics ACS, and this diagnosis should be considered when evaluating young patients who present with ACS with or without classical risk factors for coronary artery disease.

Case Report

We report a case of a 45-year old man who presented with chest pain typical of ACS. He had no risk factors except for a smoking history of 2.5 pack-years. Once the clinical findings suggested acute inferolateral myocardial infarction, the patient underwent emergent cardiac catheterization, which revealed left anterior descending coronary artery dissection. This in itself is not a common cause of inferolateral ST elevation changes on electrocardiogram.

Conclusion

This case highlights the fact that although SCAD is a rare entity, it is increasingly being recognized as a significant cause of ACS. Urgent angiography should be considered if SCAD is suspected, because early diagnosis and appropriate management significantly improve the outcome in these patients.     

Coronary revascularization in multivessel disease. Which is better, stents or surgery?

Coronary artery disease (CAD) remains the major cardiovascular health issue in contemporary clinical practice. Treatment options for multivessel CAD include medical therapy, percutaneous coronary intervention (PCI), and coronary artery bypass grafting (CABG). Here, the authors review the most recent data that compare intracoronary stenting to CABG in multivessel disease. They address therapeutic issues surrounding proper selection of the optimal revascularization strategy and give special consideration to high-risk populations, such as patients with diabetes.     

Revascularization strategies in patients with Type 2 diabetes mellitus

This review aims to describe new developments in coronary revascularization strategies for patients with pre-existing Type 2 diabetes mellitus (DM). Recommended strategies for revascularization have been an active area of study with recent important developments. In patients with Type 2 DM and multivessel coronary artery disease (CAD), coronary artery bypass graft (CABG) surgery is the preferred method for revascularization. Patients with DM are at increased risk for diffuse cardiovascular disease due to the proinflammatory, prothrombotic effects of chronic hyperglycemia. In patients undergoing percutaneous coronary intervention, drug-eluting stents and more potent antiplatelet agents especially in those presenting with acute coronary syndromes should be employed.     

New insights in the pathophysiology of acute myocardial infarction detectable by a contemporary troponin assay

Objectives

ST-elevation and non-ST-elevation myocardial infarction (STEMI, NSTEMI) are considered two distinct pathophysiologic entities. We evaluated cardiac troponin I (cTnI) release in STEMI and NSTEMI using a “contemporary” (CV > 10 to 20% at the 99th percentile concentration) cTnI assay for patients undergoing early percutaneous coronary intervention (PCI).

Design and methods

856 patients with suspected acute coronary syndrome consecutively admitted to the Emergency Department of the Maggiore Hospital of Novara (225 STEMI and 135 NSTEMI) were selected according to: 1) early (≤ 4 h from admission) and successful PCI; and 2) cTnI measurements at ED presentation and within 24 h. The influence of the MI type on cTnI concentrations at baseline and after PCI as well as the velocity of cTnI [cTnI V = absolute increase (after log conversion of cTnI measurements) / delay between the two measurements] was studied by multiple regression analysis, adjusting for patient parameters.

Results

A statistically significant interaction between MI type and time from symptoms was reported on cTnI concentrations (p < 0.0001): STEMI and NSTEMI differed for cTnI releases at admission and after revascularization. Higher cTnI V in STEMI was detectable in patients admitted within 6 h from symptoms. Baseline cTnI concentrations were lower in patients with a history of coronary artery disease (CAD) and increased with aging (p < 0.0001). In the elderly (> 75 years), the cTnI V was significantly increased.

Conclusion

STEMI and NSTEMI patients have different patterns and dynamics of cTnI release influenced by the interaction with time from symptoms, by aging and history of CAD.     

Reference chart of inspiratory muscle strength: a new tool to monitor the effect of pre-operative training

Objectives

To develop a reference chart to monitor inspiratory muscle strength during pre-operative inspiratory muscle training for patients at high risk of developing postoperative pulmonary complications awaiting coronary artery bypass graft (CABG) surgery.

Design

Secondary data analysis using patients from the intervention arm of a randomised clinical trial.

Setting

University medical centre.

Participants

Patients at high risk of developing postoperative pulmonary complications awaiting CABG surgery.

Interventions

Patients performed inspiratory muscle training seven times per week for at least 2 weeks before surgery.

Main outcome measures

Maximal inspiratory muscle strength.

Results

A new reference chart was produced using a non-linear time trend model with a normal error structure.

Conclusions

The chart is a novel tool for monitoring the progress of inspiratory muscle training for physiotherapy practice. Wider use of this chart is recommended.     

Predictive value of electrocardiogram in diagnosing acute coronary artery lesions among patients with out-of-hospital-cardiac-arrest

Aims

Acute coronary lesions are known to be the most common trigger of out of hospital cardiac arrest (OHCA). Aim of the present study was to assess the predictive value of ST-segment changes in diagnosing the presence of acute coronary lesions among OHCA patients

Methods

Findings of coronary angiography (CA) performed in patients resuscitated from OCHA were retrospectively reviewed and related to ST-segment changes on post-ROSC electrocardiogram (ECG)

Results

Ninety-one patients underwent CA after OHCA; 44% of patients had ST-segment elevation and 56% of patients had other ECG patterns on post-ROSC ECG. Significant coronary artery disease (CAD) was found in 86% of patients; CAD was observed in 98% of patients with ST-segment elevation and in 77% of patients with other ECG patterns on post-ROSC ECG (p = 0.004). Acute or presumed recent coronary artery lesions were diagnosed in 56% of patients, respectively in 85% of patients with ST-segment elevation and in 33% of patients with other ECG patterns (p < 0.001). ST-segment analysis on post-ROSC ECG has a good positive predictive value but a low negative predictive value in diagnosing the presence of acute or presumed recent coronary artery lesions (85% and 67%, respectively)

Conclusions

Electrocardiographic findings after OHCA should not be considered as strict selection criteria for performing emergent CA in patients resuscitated from OHCA without obvious extra-cardiac cause; even in the absence of ST-segment elevation on post-ROSC ECG, acute culprit coronary lesions may be present and considered the trigger of cardiac arrest     

Electrocardiographic algorithms for predicting the complexity of coronary artery lesions in ST-segment elevation myocardial infarction in ED

Objective

In reperfusion strategy for ST-elevation myocardial infarction (STEMI), emergency surgical bypass grafting might be considered for patients with significant multivessel coronary diseases complicated by cardiogenic shock. The culprit lesions in STEMI can be predicted from electrocardiographic (ECG) findings. However, whether the complexity of coronary artery lesions in STEMI can be predicted from characteristic ECG findings remained unclear.

Materials and Methods

The initial 12-lead ECG parameters in each lead recording from patients with STEMI receiving primary percutaneous coronary intervention within 12 hours were retrospectively analyzed. A sequential ECG algorithm was developed to predict the complexity of coronary artery lesions.

Results

In patients with inferior wall STEMI, the presence of the following 2-step criteria indicated 3-vessel disease (3VD), with a sensitivity of 92.1% and a specificity of 81.8%: (1) ST depression or flat T wave in leads V₅ or V₆; and (2) ST elevation of more than 2 mm in at least 1 of II, III, aVF, or Q (loss of septal r) without ST elevation in aVR. In patients with anterior wall STEMI, the following criteria indicated 3VD: (1) ST elevation of more than 4 mm in at least 1 of the precordial leads and combined with QRS interval of more than 120 ms; then (2) a flat T wave over aVR, or aVL combined with flat T wave ST depression over lead I or Q wave over all leads II, III, and aVF. This algorithm detects patients with 3VD with a sensitivity of 76.5% and a specificity of 100%. However, when the whole algorithm is completed, the sensitivity can reach up to 88.4% and the specificity can still be 100%.

Conclusion

By using this ECG algorithm, 3VD might be distinguished early from single-vessel disease in patients with STEMI for appropriate reperfusion strategy.     

Pros,Cons, and Organization of Prehospital Thrombolysis

Background

Early initiation of reperfusion therapy in ST-segment elevation myocardial infarction improves outcome. Prehospital thrombolysis (PHT) is 1 strategy to deliver earlier reperfusion.

Objective

The goal of this study was to discuss the pros and cons of PHT and to describe the implementation of a program of PHT in the Hunter Region of Australia.

Methods

Recent literature on PHT was reviewed to present a critical assessment of the evidence to support PHT. Different models of PHT are presented including the experience of the introduction of the Hunter program.

Results

Meta-analyses of clinical trials and registries have shown that PHT significantly decreases the time to thrombolysis, with reduction in the incidence of cardiogenic shock and a trend to a mortality benefit. The STREAM study reinforces current policy, which favors primary percutaneous coronary intervention (PCI) over thrombolysis, providing that PCI can be performed within an appropriate time interval; emphasizes that timely thrombolysis linked to an early invasive strategy provides an equivalent outcome when timely primary PCI is not possible; and supports other published experience that early-rescue PCI can be performed safely after administration of PHT. Although PHT can be implemented by trained paramedics working with on-board physicians, the Hunter Region has successfully used paramedics and ECG telemetry in consultation with hospital-based physicians. When the time to open the artery is ≤90 minutes, primary PCI is preferred. When the time to open the artery is >90 minutes, PHT with immediate transport postthrombolysis to a PCI-capable hospital is feasible and effective.

Conclusions

PHT delivered by trained paramedics with telemetery backup to assist ECG interpretation is feasible and delivers the prospect of early reperfusion.     

Spontaneous Coronary Artery Dissection in a 27-Year-Old Woman

Background

Spontaneous coronary artery dissection (SCAD) causes acute coronary syndromes or sudden death in young patients who are often lacking classic coronary disease risk factors. Systemic inflammatory and connective tissue diseases have been suggested as risk factors for SCAD.

Objective

To review the risk factors, diagnosis, and management of this uncommon but life-threatening disease.

Case Report

We report a case of a 27-year-old woman with a history of an ill-defined inflammatory arthropathy who presented with an acute ST-elevation myocardial infarction. SCAD was diagnosed by coronary angiography. Percutaneous coronary intervention was attempted but was unsuccessful. The patient recovered uneventfully with medical management and was ultimately diagnosed with systemic lupus erythematosus.

Conclusions

SCAD is a rare but important cause of acute coronary syndromes and sudden death. It commonly occurs in young women. Although pregnancy is the most well-established risk factor, systemic inflammatory and connective tissue diseases have also been suggested as risk factors.     

Identifying False-positive ST-elevation Myocardial Infarction in Emergency Department Patients

Background

In a push to treat ST-elevation myocardial infarction (STEMI) patients with primary percutaneous coronary intervention (PCI) within 90 min of door-to-balloon time, emergency cardiac catheterization laboratory activation protocols bypass routine clinical assessments, raising the possibility of more frequent catheterizations in patients with no culprit coronary lesion.

Objective

To determine the incidence, predictors, and prognosis of false-positive STEMI.

Methods

We followed a prospective cohort of patients diagnosed with STEMI by usual criteria receiving emergency cardiac catheterization with intention of primary PCI between January 2005 and December 2007 at a tertiary care center. False-positive STEMI was defined as absence of a clear culprit lesion on coronary angiography.

Results

Of 489 patients who received emergency cardiac catheterization indicated for STEMI, 54 (11.0%, 95% confidence interval [CI] 8.3–13.8) had no culprit lesion on coronary angiography. Independent predictors of false-positive STEMI were absence of chest pain (odds ratio [OR] 18.2, 95% CI 3.7–90.1), no reciprocal ST-segment changes (OR 11.8, 95% CI 5.14–27.3), fewer than three cardiovascular risk factors (OR 9.79, 95% CI 4.0–23.8), and symptom duration longer than 6 h (OR 9.2, 95% CI 3.6–23.7); all p < 0.001. Using predictors, we modeled a risk score that achieved 88% (95% CI 81–94%) accuracy in identifying patients with negative coronary angiography. Among the false-positive STEMI patients, 48.1% had other serious diagnoses related to their electrocardiographic findings.

Conclusion

When the diagnosis of STEMI is in doubt, clinicians may use predictors to quickly reassess the likelihood of an alternative diagnosis.     

Effects of Aggressive Statin Therapy on Patients With Coronary Saphenous Vein Bypass Grafts: A Systematic Review and Meta-Analysis of Randomized,Controlled Trials

Objectives

The aim of this study was to investigate the effectiveness and safety of aggressive statin versus moderate statin therapy on patients with saphenous vein grafts (SVGs) in randomized, controlled trials (RCTs).

Methods

We searched MEDLINE (1980–June 2012), the Cochrane Controlled Trials Register, EMBASE, Science Citation Index, and PubMed (to June 2012), and found 10 relevant RCTs, including 7 substudy analyses from a Post-CABG trial, and 1 pooled analysis of the PROVE-IT TIMI 22 trial (Pravastatin or Atorvastatin Evaluation and Infection Therapy-Thrombolysis in Myocardial Infarction 22 Investigators) and A to Z trial. Early intensive vs a delayed conservative simvastatin strategy in patients with acute coronary syndromes; phase Z of the A to Z trial.

Results

A total of 6645 of participants, ages ranging from 21 to 75 years old, were treated with coronary artery bypass graft (CABG) and were followed for 2 to 5 years. Eight studies showed that aggressive statin therapy had lower LDL-C levels and a decrease of 39% in graft atherosclerotic progression, 12% in new occlusions, and 19% in new lesions more than moderate statin therapy. Three reports indicated that aggressive statin therapy lowered the risk of repeated myocardial infarction more than moderate statin therapy for coronary revascularization (95% CI, 0.66–0.95; risk ratio [RR] = 0.80; and 95% CI, 0.66–0.85; RR = 0.75) and lowered the risk of cardiac death as well (95% CI, 0.64–1.08; RR = 0.83). Aggressive statin therapy had safety similar to that of moderate statin therapy except for a slight increase in myopathic events and aminotransferase levels. Seventy percent to 90% of patients took statin treatment as prescribed in long-term.

Conclusions

Compared with moderate statin therapy, long-term aggressive statin lowered the LDL-C level significantly, further decreased the atherosclerotic progression of SVG, reduced the risks of repeated myocardial infarction and coronary revascularization after CABG, and revealed similar patient compliance and statin-related adverse effects but slightly increased myopathy events and aminotransferase levels.     

Association between angiographic culprit lesion and out-of-hospital cardiac arrest in ST-elevation myocardial infarction patients

Background

Factors related to the occurrence of out-of-hospital cardiac arrest (OHCA) in ST-elevation myocardial infarction (STEMI) are still poorly understood. The current study sought to compare STEMI patients presenting with and without OHCA to identify angiographic factors related to OHCA.

Methods

This multicenter registry consisted of consecutive STEMI patients, including OHCA patients with return-of-spontaneous circulation. Patients were treated with primary percutaneous coronary intervention (PCI) and therapeutic hypothermia when indicated. Outcome consisted of in-hospital neurological recovery, scored using the Cerebral Performance Categories (CPC) scale, and 1-year survival. Logistic regression was used to identify factors associated with OHCA and survival was displayed with Kaplan–Meier curves and compared using log rank tests.

Results

In total, 224 patients presented with OHCA and 3259 without OHCA. Average age was 63.3 years and 75% of patients were male. OHCA occurred prior to ambulance arrival in 68% of patients and 48% required intubation. Culprit lesion was associated with OHCA: risk was highest for proximal left coronary lesions and lowest for right coronary lesions. Also, culprit lesion determined the risk of cardiogenic shock and sub-optimal reperfusion after PCI, which were strongly related to survival after OHCA. Neurological recovery was acceptable (CPC ≤ 2) in 77.1% of OHCA patients and did not differ between culprit lesions.

Conclusions

In the present STEMI population, coronary culprit lesion was associated with the occurrence of OHCA. Moreover, culprit lesion influenced the risk of cardiogenic shock and success of reperfusion, both of which were related to prognosis of OHCA patients.     

Extracorporeal membrane oxygenation–assisted primary percutaneous coronary intervention may improve survival of patients with acute myocardial infarction complicated by profound cardiogenic shock

Purpose

The aim of this study was to evaluate the impact of extracorporeal membrane oxygenation (ECMO) assistance on the clinical outcome of patients with acute myocardial infarction (AMI) that is complicated by profound cardiogenic shock (CS) who received primary percutaneous coronary intervention (PCI).

Materials and Methods

We collected patients from January 2004 through December 2006 (stage 1); 25 patients who presented with AMI and received primary PCI and had profound CS were enrolled in the study. Intraaortic balloon counterpulsation (IABP) was the only modality for extracorporeal support in our hospital. From January 2007 through December 2009 (stage 2), 33 patients who presented with AMI and received primary PCI and had profound CS were enrolled; for this stage; both intra-aortic balloon counter-pulsation and ECMO support were available in our facility.

Results

A Kaplan-Meier survival analysis displayed significantly improved survival for patients in stage 2 (P = .001; 1-year survival in stage 1 vs 2; 24% vs 63.64%). Patients presenting with either STEMI (ST segment elevation myocardial infarction) or NSTEMI (Non-ST segment elevation myocardial infarction) benefited from ECMO-assisted PCI (P < .05). In stage 1, patients with refractory ventricular tachycardia/ventricular fibrillation had a very low survival rate; however, in stage 2, the survival rate of patients with and without refractory ventricular tachycardia/ventricular fibrillation was similar (P = .316).

Conclusion

Extracorporeal membrane oxygenation–assisted PCI for patients with AMI that is complicated by profound CS may improve the 30-day and 1-year survival rates.     

Primary Angioplasty in Patient with St-Segment Elevation Myocardial Infarction in the Setting of Intentional Carbon Monoxide Poisoning

Background

ST-segment elevation myocardial infarction (STEMI) due to coronary artery occlusion in the setting of acute carbon monoxide (CO) poisoning is a very rare presentation.

Objective

Our aim was to report on the use of primary angioplasty in a patient with STEMI in the setting of CO poisoning.

Case Report

A 36-year-old man with retrosternal chest pain was admitted after exposure to CO. The initial electrocardiogram (ECG) showed ST depression in I, aVL, and V3−V4 with slight ST elevation in II, III, aVF leads. Toxic carboxyhemoglobin level of 22% and troponin I of 2.19 μg/L were confirmed. After oxygen therapy the chest pain diminished, but after about 15 h it returned. The repeat ECG revealed normalization of previous ST depression with persistent ST elevation in II, III, aVF leads. The troponin I concentration was 5.94 μg/L. An echocardiogram demonstrated an apex hypokinesia involving the adjacent segments of the anterior and lateral wall. On the coronary angiogram, an acute occlusion of the distal left anterior descending coronary artery was confirmed. Primary percutaneous coronary intervention (PCI) of the infarct-related artery was performed. After PCI, the patient was symptom free and had partial ST-segment elevation resolution. The patient was discharged home after 7 days, with persistent ST-T changes and mild hypokinesia of the apex suggesting myocardial injury.

Conclusions

Patients with toxic CO exposure who have symptoms of STEMI should be carefully evaluated with serial ECG, cardiac necrosis marker measurements, and an echocardiogram. When there is evidence of myocardial injury, a wider use of coronary angiography can identify patients who could benefit from PCI.     

Patients with coronary disease fail observation status at higher rates than patients without coronary disease

Background

Few studies have evaluated emergency department (ED) observation unit chest pain protocols for optimal patient characteristics and admission rates. At our 35?000-visits/y ED, we implemented a chest pain protocol for our observation unit that allowed emergency physicians to admit patients with known coronary artery disease (CAD).

Methods

We performed a retrospective chart review of all observation unit patients admitted under the chest pain protocol from April 1, 2006, to May 31, 2007. We compared the outcomes of patients who had a history of CAD with those who did not.

Results

Five hundred thirty-one patients were admitted to the observation unit under the chest pain protocol for the 14-month study period. Of these patients, 125 (23.5%) had a history of CAD. Patients with a history of CAD had a higher inpatient admission rate ( 24% vs 8.6%; P < .001), higher rate of a positive stress test or positive coronary computed tomographic scan (32.3% vs 6.9%; P < .001), a higher rate of cardiac catheterization (12% vs 5.9%; P = .02), and a higher rate of stent placement or coronary artery bypass graft (CABG) (7.2% vs 2.2%; P = .007). In multivariate analysis, patient history of CAD was an independent predictor of hospital admission (P = .005) and stent placement or CABG (P = .030).

Conclusion

Patients with known CAD who were admitted to the ED observation unit failed observation status (ie, required hospitalization) and had higher rates of positive testing than those without CAD.     

Comparative effectiveness of revascularization strategies in stable ischemic heart disease: current perspective and literature review

Percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) are established strategies for coronary revascularization in the setting of ischemic heart disease. Multiple randomized controlled trials and observational studies have compared the impact of the two modalities on the patients’ quality of life, mortality and morbidity, as well as the cost–effectiveness of these modalities in different clinical setting. CABG is the preferred strategy for revascularizations in patients with multi-vessel disease, especially in those with higher risk secondary to associated diabetes, left ventricular dysfunction or more complex lesions. PCI is a reasonable revascularization modality in patients with ischemia and single or low-risk multi-vessel disease and those with unprotected left main with low complexity anatomy. Compared with PCI, CABG is associated with less repeat revascularization, better quality of life and improved survival in high-risk patients. Although CABG is associated with higher cost, it is probably associated with a reasonable cost per quality-adjusted life-year gained in many patients. Therefore, CABG will often be a cost-effective strategy, especially in patients with high angiographic complexity and/or diabetes.     

The use of exercise stress testing for the management of low-risk patients with chest pain

Objective

This retrospective study assessed the contribution of exercise stress testing (EST) in the evaluation of patients with low risk for coronary heart disease who presented to the emergency department (ED) with chest pain.

Basic Procedures

The study included 175 patients who presented to the ED with chest pain and underwent EST between January 1, 2005, and November 30, 2006.

Main Findings

After the EST, 113 patients were discharged, and 62 were admitted. Exercise stress testing's positive predictive value for coronary artery disease among admitted patients was 35.7%, and sensitivity was 95.2%.Exercise stress testing's negative predictive value among discharged patients was 99.1%. None of the 113 discharged patients returned to the ED for cardiac reasons during the 30-day follow-up period.

Principal Conclusion

A chest pain unit or a parallel facility for evaluating patients with chest pain and with low risk for active coronary disease is necessary for detecting low-risk patients who eventually need cardiac intervention.     

Cannabis-associated Myocardial Infarction in a Young Man with Normal Coronary Arteries

Background

The use of cannabis is not usually regarded as a risk factor for acute coronary syndrome. However, several cases of myocardial infarction (MI) associated with cannabis use have been reported in the scientific literature. The etiology of this phenomenon is not known.

Objectives

To present a case of cannabis-associated MI in which atherosclerotic coronary disease was excluded as a potential etiology by intravascular ultrasound examination, and briefly review the other possible mechanisms by which this effect may be mediated.

Case Report

We present the case of a previously healthy 21-year-old man who regularly smoked cannabis and presented to the Emergency Department with ST-elevation myocardial infarction after participating in a sport. He was also a cigarette smoker, but had no other conventional cardiovascular risk factors. At coronary angiography, a large amount of thrombus was found in the left anterior descending coronary artery. He recovered with medical treatment, and subsequent intravascular ultrasound examination showed no evidence of atherosclerosis at the site of the thrombus.

Conclusion

Cannabis-associated MI is increasingly recognized. The etiology is unclear, but we believe this is the first report of the phenomenon where atherosclerotic plaque rupture has been excluded as the cause with a high degree of confidence.     

Use of Drug-Eluting Stents in Patients With Coronary Artery Disease and Renal Insufficiency

Renal insufficiency (RI) has been shown to be associated with increased major adverse cardiovascular events after percutaneous coronary intervention. We reviewed the impact of RI on the pathogenesis of coronary artery disease and outcomes after percutaneous coronary intervention in the form of drug-eluting stent (DES) implantation in these high-risk patients. We searched the English-language literature indexed in MEDLINE, Scopus, and EBSCO Host research databases from 1990 through January 2009, using as search terms coronary revascularization, drug-eluting stent, and renal insufficiency. Studies that assessed DES implantation in patients with various degrees of RI were selected for review. Most of the available data were extracted from observational studies, and data from randomized trials formed the basis of a post hoc analysis. The outcomes after coronary revascularization were less favorable in patients with RI than in those with normal renal function. In patients with RI, DES implantation yielded better outcomes than did use of bare-metal stents. Randomized trials are needed to define optimal treatment of these high-risk patients with coronary artery disease.ADMA = asymmetric dimethylarginine; BMS = bare-metal stent; CAD = coronary artery disease; CIN = contrast agent—induced nephropathy; DES = drug-eluting stent; DM = diabetes mellitus; MACE = major adverse cardiac event; MI = myocardial infarction; PCI = percutaneous coronary intervention; PES = paclitaxel-eluting stent; RI = renal insufficiency; SES = sirolimus-eluting stent; ST = stent thrombosis; TLR = target lesion revascularization; TVR = target vessel revascularizationRenal insufficiency (RI), defined as creatinine clearance lower than or equal to 60 mL/min, is prevalent in patients with coronary artery disease (CAD).^1-5 In patients with acute coronary syndrome undergoing percutaneous coronary intervention (PCI), even mild RI is an independent predictor of worse outcomes.¹ Renal insufficiency is a potent risk factor for CAD and qualifies as a coronary risk equivalent. Chronic RI not only increases cardiovascular event risk but also is associated with worse outcomes if an event occurs.⁶ Diagnostic coronary angiography and PCI are used less frequently in patients with reduced renal function; risk of complications from these procedures is increased in the presence of RI.^7,8 This increased risk has been shown to occur at even moderate levels of RI, despite the use of advanced stent technology and optimal adjunctive medical therapy.⁹Best et al¹⁰ reported an RI prevalence of 49.1% in patients undergoing elective PCI. In that study, RI had a negative impact similar to that of diabetes mellitus (DM) on cardiovascular outcomes.¹⁰ One year after PCI, chronic RI was associated with a doubling of mortality in patients with mild RI, a 5-fold increase in patients with moderate RI, and a 12-fold increase in patients with severe RI.¹⁰ In primary PCI for myocardial infarction (MI), a notable incremental reduction in survival was evident for each decline of 10 mL/min in creatinine clearance.¹¹ Unfortunately, most randomized trials of patients undergoing PCI have excluded patients with severe RI.^12,13 This narrative review aims to identify the impact of a drug-eluting stent (DES) in the performance of PCI in patients with RI.